4646 4650.output

* GB785053 (A)

Description: GB785053 (A) ? 1957-10-23

Improvements in or relating to the production of alkylene oxide polymers

Description of GB785053 (A)

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BE544935 (A) DE1109901 (B) FR1146098 (A) US2870099 (A) US2870100 (A) BE544935 (A) DE1109901 (B) FR1146098 (A) US2870099 (A) US2870100 (A) less Translate this text into Tooltip

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

( Po EATEGN c W al Dc ATIDO S Tnwontors: EDWARD TEGGIN BORROWS and DAVID GORDON STEWART Date of filing Complete Specification Dec 30, 1955. Application Date Feb 4, 1955. Complete Specification Published Oct 23, 1957. 785,05 t No 3455/55 Index at Acceptance:-Class 2 ( 5), R 27 K 2 C( 9: 10: 12), R 27 K 2 F. International Classification: -C 08 g. COMPLETE SPECIFICATION Improvements in or relating to the Production of Alkylene Oxide Polymers We, PETROCHEMICALS LIMITED, a British Company, of 170, Piccadilly, London, W 1, do hereby declare the invention, for which we pray that a patent may be grantedto us, and the method by which it is

to be performed, to be particularly described in and by the following statement:- This invention relates to the production of alkylene oxide polymers and is particularly but not exclusively applicable to the production of ethylene oxide polymers and propylene oxide polymers. It is an object of the present invention to provide an improved process for the production of polymers of aikylene oxides and particularly polymers of high molecular weight. According to the present invention a process for the production of alkylene oxide polymers comprises bringing an alkylene oxide into contact with a polymerisation catalyst of the general formula:w i Me Me(OR) wherein Me is a metal selected from Groups II and III of the Periodic Table, OR is an alkoxy radical, and x is the valency of the metal Me. The preferred catalysts for use in the process of the present invention are the allkoxides of aluminium, zinc and magnesium Other Group II and III metals, such as scandium, gallium, indium and thallium may also be used in the process of the present invention but their higher cost generally precludes their wide employment The alkoxides can be derived from primary, secondary or tertiary alcohols. The polymerisation reaction of the present invention may be carried out in the presence of a solvent, e g an aromatic or an aliphatic hydrocarbon, a chlorinated hydrocarbon or an ether, or without a solvent; and the reaction time may vary from a few hours to several days The temperature at which the reaction is carried out can be between 0 C and 2000 C or higher, and the pressure under which the reaction is carried out can be from atmospheric to 40 atmospheres or higher The choice of catalyst and temperature at which the reaction is carried out are an effective 50 means of controlling the viscosity of the resulting polymer. In carrying out the process of the present invention the alkylene oxide is generally added to the catalyst or more conevniently to a solu 55 tion of the catalyst in e g benzene, but the addition may be in the reverse order if desired The resulting mixture is then allowed to reach, or if necessary is heated to, the desired reaction tempeiature at which it is maintained for 60 the required time, usually with constant or intermittent stirring In some cases external cooling may be necessary to remove excess heat of reaction in the initial stages The reaction is exothermic, but the reaction mix 65 ture can, if necessary, be heated to ensure completion Preferably the reaction is carried out under pressure in an autoclave. At the end of the reaction, the excess oxide is recovered by distillation or by distillation 70 combined with precipitation by means of a suitable non-solvent, e g a paraffinic solvent, and the

resulting polymeric product purified by washing with a liquid (e g an aliphatic hydrocarbon) in which the polymer is insol 75 uble, or by dissolving the polymeric product in a solvent and slowly precipitating the polymer by the addition of a liquid which is a non solvent for the polymer but which is miscible with the original solvent Concentration of 80 the filtrate from this latter operation usually yields low molecular weight oils, the amount of which depends on the catalyst used. The polymer may be freed from catalyst by dissolving in water, preferably water contain 85 ing a small amount of ammonium hydroxide, filtering off metal hydroxide and evaporating the solution, or if insoluble in water, by extraction with a dilute mineral acid. The polymers produced by the process of 9 Q 785,053 the present invention are yaluable as thicken: ing agents The high molecular weight polymers from ethylene oxide may be processed into thin water soluble films. The following examples illustrate the process of the present invention The parts are parts by welght unless otherwise stated: EXAMPLE 1 Gaseous ethylene oxide -( 88 7 parts) was added to a solution of aluminium n-butoxide ( 0.5 parts) in benzene ( 88 parts) After maintaining the mixture at 20 C for 10 days, the excess ethylene oxide was distilled off and the resulting benzene solution was then added slowly to petroleum ether ( 100 parts) with stirring -A colourless solid ( 3 5 parts) was precipitated and was filtered off and dried The relative viscosity (fr) of this polymer in 0 1 %trichl oroethylene solution was 1 468 Concentration of the filti ate gave no other product. The solidcwas dissolved in water ( 500 parts, containing 1 part of concentrated ammonia) and refluxed for two hours A white precipitate of inorganic material was obtained, which was filtered off The polymer which was recovered from the aqueous solution by disllng off the water, was dissolved in benzene and precipitated with petroleum as described above The intrinsic viscosity of the polymer was 2 844. X EXAMPLE 2 Liquid ethylene oxide ( 88 7 parts) was rapidly run into a cooled solution of aluminium n-butoxide ( 0 5 parts) in benzene ( 8 8 parts): in an autoclave which was then heated at 100 C for 65 hours The pro= -duct was diluted with benzene ( 100 parts), excess ethylene oxide distilled off and the resulting solution precipitated with petroleum ether as described in Example 1 A colourless solid ( 16 parts), of nir= 1 148, was obtained and concentration of the filtrate yielded an Qily residue ( 2 7 parts). e EXAMPLE 3 Using the procedure described in Example 2, a mixture of ethylene

oxide ( 88 1 parts), benzene ( 8 8 parts) and aluminium iso-propoxide ( 0 7 parts) was heated at 100 C for hours A colourless polymer ( 31 4 parts), of /r= 1 228, and an oily residue ( 1 6 parts) were obtained _ EXAMPLE 4 : Following the procedure described in Example 2, a mixture of ethylene oxide ( 88 7 parts), benzene ( 8 8 parts) and magnesium tert-butoxide ( 05 parts) was heated at 107 C for 17 hours A colourless polymer ( 8 4 parts), of r 1 3311, and an oily residue ( 2 0 parts) were obtained. EXAMPLE 5 Following the procedure described in Example' 2, 'amixtire of ethylene oxide ( 88 7 parts), benzene ( 8 8 parts) and zinc kertbutoxide ( 0 5 parts), was heated at 100 C. for 16 hours A colourless polymer ( 3 8 parts), of /r= 1 5132, and an oily residue ( 0 8 parts) were obtained. EXAMPLE 6 A mixture of 1,2-propylene oxide ( 80 parts) and aluminium tert-butoxide ( 0 5 parts) was 70 heated in an autoclave at 130 C for 40 hours. After removing excess oxide from the product by distillation, the polymeric product was extracted with hot dilute hydrochloric acid, and then dried A colourless solid ( 5 0 parts), 75 of r= 1 3574, was obtained which was soluble in most organic solvents but insoluble in water. The polymers produced as described above have molecular weights above 20,000 as deter 80 mined by intrinsic viscosity measurements of solutions thereof A sample of known molecular weight of 20,000 having an intrinsic viscosity of 0 5 in solution was used as a basis fot comparison 85

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* GB785054 (A)

Description: GB785054 (A) ? 1957-10-23

An improved device for measuring distance along a line on a map, or the like


COMPLETE SPECIFICATION An improved Device for Measuring Distance along a Line on a Map, or the alike We, TBAIZ LIMITED, a British Company, of 2, Broad Street Place, London, E.C.2, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to devices for measuring distance along a line on a map, chart, graph or the like, and has for an object to provide a device which is both compact and capable of directly indicating long distances. The invention may be broadly defined as a device for measuring distance along a line on a map, chart, graph or the like (hereinafter, for convenience, termed a map measurer) wherein a plurality of drums are rotatably enclosed end-to-end in a rigid holder, such as a tubular housing, in one end of which is journalled a maD-engaging wheel geared to the adjacent drum whilst the pairs of adjacent drums are interconnected by lost-motion couplings whereby the second drum of a pair is picked up and rotated by the first drum only after a predetermined angular rotation of the latter, each drum bearing on its cylindrical surface calibration or scale markings adapted to register with a window or slit in the holder. Preferably, the drums carry numerals, on the decimal scale, which successively register with the window or slit in the holder, thus giving a direct reading of distance. Alternatively, however, each drum may carry an oblique line around its circumference to register with a scale or scales engraved along the window or slit. This latter arrangement enables one device to be used for maps of different scalese.g. 2" and 1" to the mile. Conveniently, the abutting ends of the drums have narrow, short projections extending in the axial direction from their circumferential surfaces, each located with respect to the calibrations on the respective drums so that, as the first drum of a pair moves from the ninth to the tenth digit position, its projection engages that on the adjacent drum and moves it from the zero to the

succeeding digit position. Alternative practical embodiments of the invention will now be particularly described by way of example only with reference to the accompanying drawings in which: Figure 1 is a general elevation of an instrument according to the invention; Figure 2 is a part-sectional elevation, to a larger scale, of one arrangement of drums; Figure 3 is a section on the line III--III of Figure 2; Figure 4 is an axial section through a drum showing an alternative construction to that of Figure 1; -fi;igure 5 is an axial section through a modified construction of instrument; Figure 6 is an elevation - of a two-drum assembly having an alternative transfer mechanism to that of Figure 2; Figure 7 is a part-sectional elevation similar to Figure 2 of the alternative shown in Figure 6; Figure 8 is a fragmentary view of an alternative drive from the map wheel; Figures 9 and 10 are fragmentary elevation and plan views, respectively, of another form of transfer mechanism, and Figure 11 is an elevation of a modified construction. Referring first to Figures 1-4, a map measuring device comprises a tubular holder 1 of about the same proportions as an ordinary fountain pen. That portion 2 of the holder which corresponds to thenib section of a pen has a transverse slot 3 through its end through which projects a part of the circumference of a knurled, toothed or serrated map wheel 4 journalled on a transverse pin 5. If the wheel 4 itself is toothed, it may mesh with an elongated pinion - (not shown) carried within the holder on an axis parallel to the pin 5. If, however, the wheel is knurled or serrated-or even, as shown, has a double-coned circumfer ence-then a gear wheel 6 is mounted beside the map wheel 4 and fixed thereto for rotation in unison with the wheel as it traverses the map surface. The gear 6 meshes with a similar gear 7 on a shaft 8 parallel with the shaft 5 and carrying a drum driving pinion 9. Within the holder is a series of relatively short cylindrical drums 10 mounted end to end, the centres of their mutually abutting end surfaces being domed at 11 so that only the

very small areas of the crests of the domes 11 -are in physical contact, thus reducing to a minimum the frictional drag between drums. At each end of a drum 10 is a short projec tion or nib 12, the two nibs being aligned on a generatrix of the cylindrical surface of the drum. -The length of a nib is slightly less than the distance between the circumferential edges of the adjacent drums 10 to avoid undesirable frictional drag-between thenib 12 and the end surface of the drum. - The cylindrical surface -of each drum 10 carries 10 numerals-O-9; 10-19; 20-29, and so on, respectivelyequally spaced on a circumferential zone, there being as many drums as the desired maximum distance to bey vindicated. The lowest order drum, carrying the- lowest series of numerals, ls mounted nearest the map wheel 4, - the - others being mounted above it in the order of their numeral calibrations. The lowest -drum 10 is prefer ably positively coupled to a contrate wheel 13 driven by the gearing 6, 7, 9 fromsthe map wheel 4. All the drums 10 are both positively located axially - and frictionally restrained against inadvertent rotation by springs (not shown) or by grub screws 14 threaded through the wall of the tubular-housing 1 and engag ing at their tips in -circumferential grooves 15 near one end of each drum. Rotation of a drum can thus only e effected by- positive drive -from - the map wheel 4 or from the adjacent~ lower order ~drum through inter engagement of the nibs 12. ~ The distance measured is read through whichever of the windows 28 aligned along a generatrix of the holder wall shows the highest -order calibration other than zero, the indications visible through the lower order windows being; -ignored. Thus, ~47 miles measured on the map is indicated in the fourth -window, whilst 9 miles is indicated in the first window. In both cases, higher order windows show 0, whilst in the case of 47 miles

measured all lower order windows show their respective- seventh calibration numerals. In order to facilitate resetting of the instru ment to zero, a knurled cap or ring 16 is rotat ably mounted on the end of the tubular holder 1 remote from the map wheel 4. The ring is captive in the upper-end of the holder 1, and is axially slidable against a biasing spring 17, which is located between the ring 16 and the highest order drum 10. In its normal posi tion, it is locked against rotation by engage ment of a pin 18 in the holder with a slot 19 in a skirt 20 of the ring. When the ring 16 is depressed, this locking pin 18 moves out of the slot 19 into a circumferential groove 21 in the skirt 20 (dotted lines in Figure 2). At the same time, a resilient detent 22 locked in a central recess 23 in the ring moves down into the path of a radial pin 24 on the upper end of a central resetting rod 25, so that as the depressed ring 16 is rotated, the detent picks up the pin 24 and rotates the rod 25 with the ring The latter end of the rod 25 is clamped in the contrate wheel 13, so 'that rotation thereof through the rod 25 by the depressed ring 16 eventually returns all the drums 10 to zero. An alternative zeroising drive is shown in Figure 5 in which the ring 16 also has a nib 12 located internally of the housing 1 to engage the upper nib 12 on the topmost drum 10. By rotating this ring 16 backwards all the- drums 10can be returned to zero. - - 1n -Figure t the- map wheel 4 and its associated gearing 6, 7, 9 is mounted in an internal sleeve 26 which can slide within the housing 1 sufficiently to bring the pinion 9 into or out of mesh with the contrate wheel -13, this sleeve 26 being biased by a light spring 27 to the out-of-mesh position, so that the zeroising effort on the knurled ring or cap 16 is relieved of the frictional drag of the gearing 6, 7, 9. The pressure necessary to cause the map wheel 4 to move without slipping over

the map surface is sufficient to cause re-mesh ing of the pinion 9 with the contrate wheel 13. The calibrated zone of each drum is prefer ably slightly recessed at-l0a to reduce fric tional drag in the holder 1 and to prevent wearing off of the calibrations during use of the device. - The holder l-described above is made~ of an opaque material and has the windows 28 - cut in its wall. Alternatively, the holder 1 may be of a transparent material, -all but the window areas of which is rendered opaque. In the modification shown in Figures 6 and 7, each pair of adjacent rotary drums 10 are separated by a fixed cylindrical spacer 29, which is a press fit within the tubular holder 1, and whose~ circumference is recessed at one point 30 to accommodate a star wheel 31 hav ing, say, four teeth 32 of equal height and dis posed at right angles to each other. This star wheel 31 is journalled on a pin 33 extending diagrammatically across the spacer 29, and the tips of its teeth 32 sweep a circle of greater diameter than the axial thickness of the spacer 29 and symmetrically centred with respect thereto. Thus, at a given stage of the rota tion of the star wheel 31, any one tooth 32 will project above or below one or other end face of the spacer by the same amount as any other tooth, as indicated in chain lines 321 in Figure 9. Considering the holder 1 in its vertical position with the map wheel 4 resting on a map surface, the underside of each drum 10 is toothed, there being preferably 10 or 20 teeth 12 or 13 (units drum) arranged around the circumference thereof. The teeth project in a generally axial direction. The upper surface of each drum-with the possible exception of the uppermost-has a pin 12a projecting in the axial direction at a point close to the periphery of the drum. This pin is dimerisioned and located so as to strike a tooth 32 of the star wheel 31 above it and carry it round through substantially 90" as the pin 12a moves past the wheel 31. While a tooth 32 of the star wheel is being thus driven, the diametrically opposite tooth engages a tooth gap on the underside of the next higher order drum 10 and steps the latter round by one tooth

pitch-i.e. one tenth or one twentieth of a complete revolution, depending on the number of teeth 12 on the drum. The star wheel 31 thus acts as a transfer mechanism for advancing a higher order drum stepwise. The assembly thus constitutes a decimal system counter, the drum 10 nearest the may wheel 4 being the units drum. In order to ensure minimum friction between the drums 10 and spacers 29, each has a central boss 11, 34, respectively, to engage the other on the axis of the tubular holder 1.- Such bosses also serve to control the depth of mesh of the driving pin 12a on a drum 10 with the star wheel 31, and of the star wheel 31 with the teeth 12 on a higher order drum. Resetting to zero is achieved by means of a central rod 25 which is both axially slidable and rotatable in the spacers 29 and which extends through the whole assembly. By pulling the rod out, or pushing it in, against spring pressure, pegs or like projections thereon (not shown) are brought into engagement with arcuate recesses in the numeral drums, and rotation of the rod 25 picks up each drum and rotates it back to zero. The units drum is preferably driven step wise through a mutilated gear 9a on the map wheel spindle 5, although a bevel gear drive may be used if preferred. It is also preferred to mount the map wheel 4 externally of the tubular holder 1 so that its spindle 5 extends diametrically across the holder below the units drum. In order to lock the units drum after each successive increment of rotation, it is preferred to select the diameter and position of the mutilated gear 9a so that two adjacent teeth 13 on the drum straddle and rest against the circumference of the mutilated gear (see Figure 6), in the manner of a Geneva clock escapement. The mutilated gear 9a is then notched at 35 radially inwards from its circumference immediately behind l-he or each driving tooth to permit clearance of the tip of the next operative tooth 13. As shown in Figure 8, the driving tooth on the mutilated gear 9a may be constituted by the leading end of a leaf spring 36 which wraps around a portion of the circumference of the mutilated gear and is anchored thereto at its trailing end 37. The circumference is preferably relieved over the portion occupied by the spring 36 and the leading end of the latter is preferably bent inwards at 38 to rest in a clearance slot 39. The spring 36 is given a radially outward set so that this leading end 38 normally stands proud of the circumference of the mutilated gear 9a to act as a pawl when it engages the trailing tooth of a pair straddling the gear. When, however, the gear has rotated through a sufficient angle to advance the units drum by one calibration, the next succeeding trailing tooth on the drum strikes

the smooth circumference of the mutilated gear and prevents further drum rotation. Continued rotation of the mutilated gear causes the leading end 38 of the leaf spring 36 to ride down the flank of the previously driven tooth 13 so as to pass beneath the tip thereof. The units drum is now again locked until the pawl 38 engages the now trailing tooth. A similar arrangement (see Figures 9 and 10) may be adopted for the transfer drive through the star wheel 31, except that the leaf spring 40 is now generally fiat, but of arcuate shape in plan to fit into a hollow partcircumferential recess 41 on the upper end of the lower order drum of the pair. The parts are arranged so that two teeth 32 of the star wheel 31 simultaneously rest on the plane end surface of the lower drum so that the rotation of the star wheel is positively prevented until the clearance recess 41 immediately in advance of the spring pawl end 42 is brought beneath the trailing tooth 12 and the latter is engaged by the proud leading or pawl end 42 of the arcuate leak spring 40. This end 42 is later depressed, as before, by riding down the flank of the lately driven tooth 12 when the star wheel 31 is locked by the engagement of the next succeeding tooth 12 with the end surface of the lower order drum 10. By doubling the number of teeth on the gear 9 or the mutilated gear 9a, the size of the map wheel 4 can be doubled for the same scale of the drum calibrations. In a further modified arrangement, shown in Figure 11, the drums 10 each have an oblique line 43 drawn from one end to the other of the circumferential calibration zone at a constant angle to a generatrix of the cylindrical surface of the drum. The edge of each window 28 is calibrated at 44, 45 in the appropriate units of distance, or alternatively each window is longitudinally bisected by a hair line carrying the appropriate scale markings. The distance measured by the map wheel 4 is then read off at the intersection of the oblique line 43 with this hair line. The drums 10 may be of any suitable material--wooa, pIastic, light alloy-and may be solid or hollow as preferred. Figures 1 and 7 show constructions suitable for wood or plastic drums- 10, whilst Figure 4 shows a con -struction suitable for metal drums. Where the same instrument is used on maps having different scales,-the readings must be multiplied by a factor depending on the change of scale-for example if the instrument is calibrated for maps having a scale of 1" to the mile, readings must be multiplied by four when it is used on x" to the mile maps. Alteinatively the map wheel 4 may be inter

changeable with wheels of different diameters in order to accommodate changes of scale of the map, and its periphery may be calibrated in fractions of the unit of distance indicated by the drums 10. Thus, as the scale of the map increases, the diameter of the map wheel 4 must be reduced in proportion. What -we claim is 1. A map measurer comprising a series of drums enclosed end-to-end in a rigid holder in one end of which is journalled a mapengaging wheel; a drive between the wheel and the adjacent drum; and lost-motion connections between pairs of adjacent drums whereby the second drum of a pair is picked up and rotated by the first drum only after a predetermined angle of rotation of the latter, each drum bearing on its cylindrical surface a scale or calibration mark- adapted to register with and be viewed through a window aper ture in the holder for indicating length or dis tance on the map. 2. A map measurer according to Claim 1 wherein each drum has a narrow short projection extending in the axial direction from an end thereof adjacent the circumference of the drum for transmitting the drive derived from the map wheel to the next adjacent drum. 3. A map measurer according to Claim 2 wherein a pair of adjacent drums have similar interengageable projections on their adjacent ends each located with respect to the calibration mark or marks on its associated drum so that interengagement occurs as the driving drum reaches its angular position of maximum indication while the driven drum is still in its zero position. 4. A map measurer according to Claim 2 wherein each drum has a number (say, ten) of discrete angular positions for stepwise indi cation of length or distance, and each drum except the last or highest order drum in the series-is at its end adjacent the next higher - order drum provided with a single projection whilst the said higher order drum has uniformly spaced projections equal in number to the number of the -discrete angular posi tions thereof, and a transfer element is inter posed between the drums to simultaneously engage projections on both drums and trans mit to the driven drum an increment of rota--non on each engagement by the projection on the driving drum.

5. A map measurer according to Claim 4 wherein the transfer element is constituted by a star wheel journalled on a fixed axis extend ing diametrally of the cylindrical surfaces of the drums. 6. A map measurer according to any pre ceding claim wherein each drum is lightly restrained against random rotation in the holder. 7. A map measurer according to any pre ceding claim wherein each drum is axially located by means of an inward projection on the holder which is engaged in a circumferen tial groove in the drum. 8. A map measurer according to any pre ceding claim wherein means is provided for manually resetting the drums to their zero positions. 9. A map measurer substantially as des cribed with reference to Figures 1S, Figure 5, Figures 6 and 7, Figure 8, Figures 9 and 10; or Figure 11 of the accompanying drawings. PROVISIONAL SPECIFICATION No. 4185, A.D. 1955. An improved Device for Measuring Distance along a Line on a Map, or the like We, TIDAL LIMITED, a British Company, of 2, Broad Street Place, London, E.C.2, England, do hereby declare this invention to be described in the following statement: - This invention relates to devices for measur ing distance along a line on a map, chart, graph or the Iike, and has for an object to provide a device which is both compact and capable of directly indicating long distances. The invention may be broadly defined as a device for measuring distance along a line on a map, chart, graph or the like wherein a plurality of drums are rotatably enclosed end-to end in tubular housing in one end of which is journalled a map-engaging wheel geared to the adjacent drum whilst the pairs of adjacent drums are interconnected by lost-motion coup lings whereby the second drum of a pair is picked up and rotated by the first drum only

after a predetermined angular rotation of the

* GB785055 (A)

Description: GB785055 (A) ? 1957-10-23

Photopolymerisation process



US2902421 (A) US2902421 (A) less Translate this text into Tooltip



& PATENT SPECIFICATION Date of filing Complete Specification: Feb 1, 1956. Application Date: Feb18, 1955 No 4857/55. ' Complete Specification Published: Oct 23, 1957. Index at acceptance:-Class 2 ( 6), P 2 D 1 A, P 2 K( 4: 7: 8), P 2 P( 2 X: 3: 5: 6 C), P 4 D 3 B 1, P 4 K( 2: 7: 8), P 4 P( 2 X: 3: 5: 6 C), P 7 D 2 A 1, P 7 K( 2: 4: 8), P 7 P( 2 X: 3: 5: 6 C), P 8 D( 21 82; 3 A), P 8 K( 2: 4: 7), P 8 P( 2 X: 3: 5: 6 C). International Classification: CO 08 f. : XCOMPLETE SPECIFICATION Photopolymerisation Process We, THE DISTILLERS COMPANY LIMITED, a British Company, of 12, Torphichen Street, Edinburgh, 3, Scotland, and

RONALD GEORGE WREYFORD NORRISH, a British Subject, of the Departmnent -of Physical Chemistry, Free School Lane, Cambridge, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present application relates to the polymerisation of ethylenically unsaturated organic monomeric compounds In particular it relates to the production of polymeric material from such compounds by bringing about their polymerisation by the action of ultra-violet light. It is known that polymerisable ethylenically unsaturated organic compounds may be polymerised by-the action of light of a suitable wave length, particularly ultra-violet light In such polymerisation reactions the rate of polymerisation and also the length of the polymer chain produced are dependent on the nature and concentration of the monomeric material and also on the intensity and wave length of the light. An object of the present invention is to provide a process for the production of polymeric material by the photopolymerisation of polymerisable ethylenically unsaturated compounds in which the rate of polymerisation is increased for a given light intensity of the appropriate wave length A further object is to provide a new class of photopolymerisation accelerators for use in such a process Accordingly, the present invention is a process for the production of polymeric material which comprises irradiating a polymerisable ethylenically unsaturated compound with ultra-violet light in the presence therein of a polynuclear aromatic hydrocarbon as photopolymerisation initiator and isolating the polymeric material so produced The term ultra violet light is employedi m its usual sense to dnote radiation having a wave-length less than about 4,000 A. The practical lower limit of the wave length of the radiation used is governed by the transmitting power of the material from which the reaction vessels etc are made For instance, soft glass will not transmit below about 3,500 A, pyrex glass will not transmit below about 3,000 A, and quartz will not transmit below about 2,000 A Pyrex is a registered Trade Mark For most purposes radiation having a wave length beitween about 2,000 A and 4,000 A is suitable. A wide range of polymeric materials can be produced according to the process of the present invention It is particularly useful when applied to the production of polymeric material from polymerisable ethylenically unsaturated compounds which possess one or more unsaturated groups having the following structural formula in their molecules CH 12 = C< Examples of such compounds are vinyl acetate, styrene, acrylonitrile, methyl methacrylate and butadiene Mixtures of one or more suitable ethylenically unsaturated compounds may be

copolymerised according to the present invention. The polymerisation of the unsaturated compounds in the process of the present invention canbe brought about under both homogeneous and heterogeneous conditions. By heterogeneous polymerisation conditions is meant polymerisation in which the reaction mixture consists of -two distinct phases Such polymerisations are of two types, namely emulsion polymerisations and suspension polymerisations In emulsion polymerisation the monomer is dispersed throughout the second phase, which is -usually aqueous, in the form of a fine emulsion which will not separate out on standing; the resultant polymeric product is in the form of a colloidal suspension 185,055 55(often loosely called an emulsion) which has through suitable windows or the like Ordinary to be coagulated or "broken" Ibefore the sunlight may be used but it is preferred to use polymer can be isolated in the solid -form In an artificial source of ultra-violet light which suspension p Iym isation the moncmei is gives an, abundance of radiation within the persed throughout the second phase, which desired wave length range Suitable sources 70 again is usually water, in the form of discrete are, for example, a mercury vapour lamp or a particles which have to be maintained in sus carbon electrode arc lamp It is usually prepension by mechanical means A polymer pro ferred to screen the light used for the photoduced by a suspension, prcoess in the form of polymerisation by means of suitable filters so particles or beads which are isolated directly that only light having the desired wave length 75 from the reaction mixture-by, for example, acts upon the polymerisation mixture. settling, filtration or centrifuging By homo Thep olymerisation according to the present geneous polymerisation is meant polymerisa invention may be initiated by using ultra tion in which the reaction mixture consists violet light containing radiation having a wide solely of one phase Such polymerisations are range of wave lengths but in practice it is 80 carried out either on the unsaturated com found that only a comparatively small portion pound alone, or on a solution of the-' com-n of the light is, in fact, initiating the polypound in a suitable inert solvent merisation The actual wave length range of It should be noted that in all types of poly this desired radiation depends primarily on merisation according to the present invention the ultra-violet light absorption of the poly 85 it is important:that any diluent used in the nucleai aromatig-hydocarbon used as photoprocess, for instance, either as dispersing polymerisation initiator and, if possible, it is medium in -heterogeneous polymerisation -or preferred to use a source of radiation which solvent in homogeneous poiymerisati 6 ion, should gives ultra-violet light of a wave length cornot absorb the ultra-violet radiation, which is responding to the maximum

absorption of the 90 being used to induce the polymerisationfi, to polymerisation initiator employed For many such an extent that the polyinerisation is-initiators the maximum absorption occurs seriously retarded or even prevented within the wave length range 2,400 to 3,000 The photopolymerisation initiators of the angstrom units and, for-instance, in the case present invention are polyfificlear aromatic of naphthalene the maximum absorption 95 hydrocarbons such as, for exaniple, naphtha occurs between 2,600 and 2,800 angstrom lene, anthracene, phenanthrene, triphenylene, units. chrysene, pyrene, 3,4-benzphenanthrehe, 1,2 The choice of suitable ultra-violet light and benzanthracene, 1,2,5,6 dibenzanthfacene, a suitable photopolymerisation initiator for the perylenie, rubrene and cofonene The readily polymerisation of any given ethylenically un 100 available polynuclear aronmatic hydrocarbons saturated compound will depend to some such as naphthalene and anthracene are useful extent upon the absorption of the monomeric polymerisation initiators It is known that such compound or compouftds employed and that hydrocarbons are transitionally formed into of the polymer or copolymer produced In excited triplet-states by irradiation with ultra order to benefit fully from the controlled poly 105 vi Olet-lig-ght-of suitable waveleigth-and it is merisation process of the present invention it believed that the po Fymerisia-on according to is important that the-absorption coefficient of the present invention is initiated -by the the ethylenically unsaturated compound or of preseice in -the reaction miixture of these the polymeric material produced should be activated ar 6 omatic moleules Th quantit of considerably less than the absorption: co 110 polynuclear aromatic hydrocarbon present in efficient of the polynuclear photopolynierisathe polymerisation ni mixtite may vary widely tion initiator, all coefficients being measured according to the nature of the polymerisabld with light of the particular wave length ranges compound and the conditions under which relied on to bring about the polymerisation. the polymerisation is brought about Qilanti By suitable selection of the wave length of 115 ties down to a few parts per million bf the the ultraviolet light emiployed and by suitable aromatic hydrocarbon serve to initiate -the choice of the photopolymerisation initiator the polymerisation, but much higher quantities polymerisation of most ethylenically ufisaturamay be employed if desired Care should also ted polymerisable compounds may be brought beitaken to ensure that the initiator chosen for about under-optimum conditions 120 any particular polymerisation reaction is not The conditions of the polymerisation proalso an inhibitor for that reaction, because cess according to the present invention may under such conditions the polymerisation rate be widely varied as is well known in the art will be slow: of

pclymerisatio D For instance the tempera'The irradiation of the polymerisable ture of the polymerisation reaction mixture is 125 ethylenically unsaturated comnpound is carried not at all critical although variations may out-under conclitii 6 ns which are well known in cause the molecular weight of the produced the art The sourceo-6 f light may be within the polymer and the rate of polymerisation to polymerisation vessel or placed outside so alter If the polymerisation isto becaried out that its rays reach the polymerisation mixture under heterogeneous conditions, the usual 130 785,055 tion are similar to polymers produced by conventional methods, i e with the aid of a peroxy catalyst, but they can have the advantage that they are not contaminated with any of the conventional polymerisation catalysts. The following examples illustrate the polymerisation of various ethylenically unsaturated compounds according to the present invention. EXAMPLES 1 TO 4 Samples of acrylonitrile containing varying amounts of anthracene as photopolymerisation initiators were placed in turn in a reaction vessel fitted with a stirrer and containing quartz windows and were subjected to the radiation from a mercury lamp after it had been filtered by passage through two glass plates These optical filters remove most of the radiation having a wave length less than about 3,000 angstrom units The temperature of the acrylonitrile was about 20 C The relative amounts of polyacrylonitrile obtained after given polymerisation times are shown in the following table, expressed as parts by weight In all cases the polymer was recovered by the addition of methanol to the reaction mixture, followed by -filtration of the precipitated polymer. emulsifying agents or suspension stabilisers may be added as required and similarly other compounds known to effect polymerisation reactions or the nature of the products may be present For instance, although an advantage of the present invention is that it provides a means of producing polymers entirely free from polymerisation catalysts such as peroxides and the like, it may, in certain cases, be advantageous to carry out the polymerisation process of the present invention on polymerisation reaction mixtures containing small proportions of any of the standard polymerisation catalysts It is important, however, that any compounds added to the polymerisation mixture should not absorb the ultra-violet light which is causing the polymerisation to such an extent that the controlled polymerisation of the process of the present invention is impaired. The polymeric material produced in the process of the present invention is in the form of a solid, i e a precipitate, a suspension or an emulsion, or in the form of a solution and it can readily be isolated by conventional procedures whidch ae well known fii the art

Such methods include precipitation, filtrations, centrifugation and the like. Polymers produced according to the invenExample No 1 2 3 4 Percentage by weight 0 0014 0 004 0 016 0 017 of anthracene Time of irradiation 9 3 5 4 5 5 0 (hours) Polymer-produced 15 1 16 4 25 42 6 In a comparative experiment the irradiation of acrylonitrile in the absence of the anthracene produced no polymerisation. EXAMPLE 5. A similar process to that described in Examples 1 to 4 was carried out, but the acrylonitrile contained 0 094 % by weight of naphthalene as photopolymerisation initiator and the unscreened radiation from the mercury lamp was employed After irradiation for 1 hour at 30 C, 200 parts by weight of polyacrylonitrile were recovered by the addition of methanol to the reaction mixture In the absence of the initiator only 83 parts by weight of polymer -were produced under identical conditions EXAMPLE 6. Two portions of vinyl acetate, one of which contained 0 011 % by weight of naphthalene, were irradiated at room temperature in similar reaction vessels fitted with pyrex glass windows Pyrex is a registered Trade Mark. These effectively remove radiation with wave lengths less than about 3000 angstrom units. The degree of polymerisation was followed by dilatometric means After four hours the sample containing the naphthalene contained approximately 1 5 times as much polyvinylacetate as the sample of pure vinyl acetate. The polymer was recovered by precipitation with methanol and isolated by filtration. EXAMPLE 7. A quartz cell was charged with monomeric styrenes contraining varying amounts, of anthracene The cell was maintained at 700 C and irradiated with light of wave length 3,500 to 4,200 A In the absence of radiation the styrene polymerised at-a slow rate-the dark reaction. When the monomer was irradiated, the polymerisation rate increased and continued at the higher rate for a time dependent on the amount of anthracene present As the polymerisation proceeds under irradiation, the 40. 785,055anthracene is -consumed and its fluorescence disappears from the reaction mixture. The results obtained are shown in the following table: Amount of anthracene present in parts by weight 2 33 4; 65 9 30 18 6 Total polymerisation to: disappearance of anthracene 2 3 3 O 5 3 7 3 % by weight Total polymerisation due to the dark reaction-% by 0 4 0 5 _ 1 1 1 6 weight

Total polymerisation due to irradiation -% by weight 1 9 2 5 4 2 5 7 Intrinsic viscosity of product 2 32 2 13 1 80 1 70 A series of different initiators were added' to samples of acrylonitrile: (A) and methyl methacrylate (M) and the solutions-irradiated for varying times and the amount of polymer formed determined by filtering off the produced polymer and washing it with ether All solutions were maintained under nitrogenduring the polymerisation which was carried out at 50 C Except where indicated the ultra-violet light used was screened by passage through a Chance O x 1 filter The results obtained are given in-the following table: Time of %Wof Initiator Monomer % of irradiation polymer = initiator _hours produced Anthracene M 0 0195 4 2 5 _ zA:: _ 0 018 3 '1 1 : Naphihalene M 0 048 4 1- 5 : =, A O 0493 4 _ 4 6 9-ethyl anthracene _ A-, 0 016 f: 4 4 2 Pyrene A 0 0245 3 75 8 5 = Chrysene -A 0 036 -3 75 8 5 1:2-benzanthracene A 0 029 3 75 5 2 :: No optical filter used The percentage of the initiator:in the unpolymerised monomer is-expressed on a molar basis, and that of the polymer produced on a weight basis Attempts to polymerise the acrylonitrile and the methyl methacrylate under the conditions described above but in the absence of any protopolymerisation initiaE tors only gave rise to a very small proportion of polymer, ie less than 1 %, in the case of methyl methacrylate and no polymer at all in the case of acrylonitrile Under similar conditions very-good photopolymerisation initiation was obtained, using 1, 2, 5, 6-dibenzanthracene -


* GB785056 (A)

Description: GB785056 (A) ? 1957-10-23

Sealing arrangement for telescopic shock absorbers



DE1115535 (B) FR1118033 (A) US2808277 (A) DE1115535 (B) FR1118033 (A) US2808277 (A) less Translate this text into Tooltip



PATENT SPECIFICATION Date of Application and filing Co 785,056 replete Specification: March 4, 1955. No 6443/55 ' Application made in Germany on March 12, i 954. Complete Specification Published: Oct 23, 1957. Index at Acceptance Classes 108 ( 3), 58 M 2 A; and 122 ( 5), B 13 (B 3 A 7 A: B 3 B 1 A: C 12). International Classification:-F 06 f, j COMPLETE SPECIFICATION Sealing Arrangement for Telescopic Shock Absorbers. e, FICHTEL & SACHES Aktiengesellschaft, the edge face 2 a, are compressed between two erman Body Corporate, of Schweinfurt am' annular plate members 8 and 9 The cornn, Germany, do hereby declare the inven pressed annular portion of the sealing member for which we pray that a patent may be 2 located between side face portions 2 b, 2 c ted to us, and the method by which it is to thickens toward the outer sealing face 2 a A 50 Derformed, to be particularly described in pressure member 6 has an annular portion by the following statement: engaging the pressure plate 9 and pressing the his inveintion relates to a sealing arrange s'ame'against the annular sealing member 2 and t for telescopic shock absorbers 'toward the pressure plate 8 which abuts is the object of the present invenition to -'againsi the inner flange 10 of the tubular con 55 ide -a: sealing arrangementfor a shock tainer member 5 ' -rber which permits a particularly C The'ainular pressure member is formed comical manufacture with a peripheral groove 7 which is engaged by t is a further object of the present invention an annular bead 11 in the tubular container )rovide in a shock absorber an annular member 5 and has an inner portion 6 a provided 60 ing means which tightly seals' along one with a bearing face on which

the piston rod 1 thereof but permits sliding of a piston rod is slidably mounted The annular pressure g another sealing edge thereof member 6 has an inner chamber 6 b comccording to the present invention a tele municating through a bore 6 c with the interior ic shock absorber having a sealing of the tubular container member 5 Members 65 ngement is provided wherein the seal for a 6, 8, 9 and 10 constitute pressure means for on rod consists of a sealing member of compressing the sealing member 2. lient material, the external diameter of During the assembly of the parts, the inner ch is smaller, before installation, than the flange 10 and the bead 11 are simultaneously rnal diameter of a tubular container mem formed by roller dies while the pressure mem 70 therefor, and, in the installed state, is en her 6 compresses the sealing member 2 The ed by pressure acting upon its faces and outer diameter of the outer edge face 2 a is rs in sealing fashion on the inner wall of slightly smaller than the inner surface of the tubular container member The thickness tubular -container member 5 as long as the he sealing member may increase radially sealing member 2 is not compressed, and, con 75 k piston rod guide may have a peripheral sequently, the sealing member can be easily ove into which the tubular container mem inserted After the outer annular portion of the wall is inserted by rolling or pressing The sealing member is compressed, the outer sealing ention will be best understood from the face 2 a is firmly pressed against the inner surowing description, by way of example, face of the tubular container member 5 and 80. an embodiment thereof, illustrated in the provides a tight seal. ompanying drawing The bead 11 and the groove 7 provide an eferring now to the drawing, the elongated axial support of the annular member 6 which on rod member 1 is sealed by an annular constitutes a bearing for the piston rod 1 so ling member 2 which has an inner annular that axial forces occurring during operation of 85 e face comprising two lips 3 and 4, and an the shock absorbers are taken up by the bead er annular edge face 2 a engaging the inner ndrical surface of the tubular container mber 5 The transverse annular side face tions 2 b and 2 c which are located adjacent Price 3 s 6 d l 11. Two lips 3 and 4 are illustrated, but it will be understood that a single inner edge face could be provided on the sealing member An 90 Price 33 p Ai a Ge Maii tion, gran be p and T men It prov abso econ It to I seali edge alon A scop arra pistc resil whii inte: her larg beai said of t A groo ber jnve folli of; acc pist seal edg out cyli men por l. 2 785,056 annulaimminilber 3 a holds the lip 3 in position rod consists of a sealing member of resilient The drawing further shows a tubular mem material, the external diameter of whikh -is bet 12

engaging the annular member 6 and smaller, before installation, than the 'interial forming a dampening chamber, an outer pro diameter of a tubular container member there-' 30 tective casing 13, a cap 14 fixedly connected for, and, in the installed state, is enlarged by to the protective casing 13, an annular member pressure acting upon its faces and bears in-sealfor attaching the telescbpicd shock-absorber ing fashion on 'the inner wall of said tubular to a vehicle and engaging the, unit: 1, 14, 13, a container member ' rubber sleeve 16, and a steel sleeve 17 tension 2 A telescopic shock absorber as-claimed in 35 ing the rubber sleeve 16 claim 1, wherein the thickness of the sealing It will be understood that each of the member increases radially. elements described above, or -two or more 3 A telescopic shock absorber as claimed in together, may also find a useful application in either of claims 1 or 2, wherein a piston rod other types of sealing arrangements differing guide has a peripheral groove into which the 40 from the types described above tubular container member wall is inserted by While the invention has been illustrated and rolling or pressing. described as embodied'in' a' sealing arrange-' 4 A telescopic shock absorber having a ment for a telescopic shock-absorber, it is not sealing arrangement substantially as described intended to be limited to the details shown, with reference to and as illustrated in the 45 since various modifications and structural accompanying drawing. changes may be made without departing in any way from the scope of the present invention For the Applicants, defined in the claims MATTHEWS, HADDAN & CO,


* GB785057 (A)

Description: GB785057 (A) ? 1957-10-23

Improvements relating to mounting arrangements for thermostats in ovens orother heated enclosures


PATENT SPECIFICATION 78 C Inventor:-ANTHONY MICHAEL HICKS. i K S Date of filing Complete Specification: March 19, 1956. Application Date: March 19, 1955 No 8071/55. Complete Specification Published: Oct 23, 1957. Index at Acceptance:-Classes 64 ( 2), T 13; and 126, B 18 A 1. International Classification:-F 24 b G Olk. COMPLETE SPECIFICATION. Improvements relating to Mounting Arrangements for Thermostats in Ovens or other Heated Enclosures. We, SIMPLEX ELECTRIC COMPANY LIMITED, a British Company, of Broadwell, Oldbury, in the County of Worcester, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention relates to mounting arrangements for thermostats in the ovens or other heated enclosures (hereinafter termed ovens) of cooking stoves Such oven being heated either electrically or by means of gas. The invention refers specifically to thermostats of the kind having a tube and rod or other thermally sensitive elongated bi-metal structure which at one end affords a mechanical output by virtue of differential expansion of the tube and rod or equivalent components of the structure and which at this end is provided with electrical contacts or valves actuated by this mechanical output, these contacts or valves usually being contained within a housing also accommodating adjusting mechanism for adjusting the operating point of the thermostat. The contacts and terminals or valves and adjustment mechanism are usually mounted in a ihousing to which the tube or outer member of the bi-metal structure is connected by means of a bush afid whilst this bush is normally of standard cross sectional dimensions for varying diameters or cross section dimensions of the tube and rod or other bi-metal structure the bush cannot be directly mounted in an aperture in the wall of the oven concerned in a manner effecting vapour tight seal, for example by welding or brazing the bush in such aperture, belPrice 3 s 6 d l cause firstly, the thermostat would not be able to survive finishing operations (such as vitreous enamelling) that would be necessary after such welding or brazing and secondly because it is

necessary that the thermostat should be removable for replacement should it not operate in a correct manner. Further, the whole thermostat cannot be accommodated bodily in the oven, and to effect a vapour tight seal with the different diameters or cross sections of the tube and rod or other bi-metal structure, different sealing components are required thereby rendering thermostats differing in respect of these diameters or cross sectional dimensions not interchangeable between one oven and another although otherwise they would be interchangeable. This appreciably complicates maintenance and supply problems as well as increasing the number of components which it is necessary to manufacture in order to enable use to be made of thermostats which merely differ in respect of diameters or cross sectional dimensions of their tube and rod or other bi-metal structures. The object of the present invention is to obviate or reduce this disadvantage. According to the present invention an entry through the oven wall of a cooking stove for the tube and rod or other thermally sensitive elongated bi-metal structure of the thermostat, effective for different cross sectional dimensions of such structure, is provided by a sleeve of internal diameter sufficient to accommodate the largest cross section of bi-metal structure required to be used, such sleeve forming a substantially gas tight extension of the oven wall and projecting from the hole in said oven wall 057 to the exterior to an extent sufficient to allow the head assembly of the thermostat to be disposed beyond a heat barrier embodied in or associated with the oven wall, and closed at its outer end by a bush or like formation of cross sectional dimensions common to thermostats having bi-metal structures of different cross sectional dimensions aforesaid. In combination with the aforesaid arrangement according to the invention the bi-metal structure may be secured internally of the oven at or near its inner end by a bracket which has a plurality of holes, sockets or like formations of different diameters or cross sectional dimensions corresponding to those of the different cross sections of bi-metal structure required to be used, and such bracket is movably mounted in the oven, or the portion thereof provided with said holes, sockets or formations is movable to present selectively the appropriate sized hole, socket or formation to the inner end of the bi-metal structure and to support same. The bracket may have a portion which partly encloses the inner end of the bi-metal structure or is interposed between this end and the mouth of the oven thereby protecting the thermostat against damage by being knocked or jarred with dishes during insertion or placement on the oven shelf adjacent to the thermostat.

The invention is now more particularly described with reference to the accompanying drawings, showing by way of example, a preferred embodiment In the drawings: Figure 1 represents a part sectional side elevation of a thermostat mounted in an oven in accordance with the present invention; Figure 2 shows, on an enlarged scale, a plan view of the mounting of the inner end of the thermostat; and Figure 3 is a sectional end elevation taken on line 3-3 of Figure 1. In this particular construction according to the present invention, a thermostat of the kind wherein the thermally sensitive structure 10 is in the form of a bi-metal tube and rod assembly which at one end is connected by means of a standard diameter bush 11 to a head assembly comprising a housing 12 containing electrical contacts, terminals or valves and adjusting mechanism for varying the operating point of the thermostat, is mounted in an oven in a cooking stove in a horizontal or approximately horizontal plane closely adjacent to the top wall 13 of the oven, the tube and rod assembly extending in a direction fore and aft of the oven at a convenient position, for example midway between the side walls of the oven. The thermostat may be provided with alternative diameters of tube for the bi-metal rod and tube assembly, for example the tube may be of half an inch diameter in some cases and of %/ of an inch diameter in other cases 70 To permit the housing 12 to remain outside the back wall 14 of the oven whilst sufficiently isolated thermally from the heat transmitted from this wall and to provide a vapour tight seal between the tube and rod 75 assembly and the back wall 14 of the oven, the latter is formed with a hole which is somewhat larger than the largest diameter of tube which is required to be used, e g. somewhat larger than i' inch diameter, and 80 a sleeve 15 preferably of copper, brass or other non-ferrous metal of an external diameter to fit within this hole is assembled around the tube and sealed to the back wall 14 of the oven conveniently by the provision S 5 of an outwardly projecting flange 16 at the inner end of the sleeve which is mechanically held against the interior face of the back wall of the oven so as to prevent the egress of hot gases or vapours from the 90 oven interior. Alternatively the flange 16 of the sleeve could be welded, brazed or otherwise united by fusion to the wall of the oven. At its rearward end the internal diameter 95 of the sleeve 15 is such as to be a close sliding-fit over the bush 11 and conveniently the sleeve is of the same diameter from end to end Ordinarily the diameter of the bush 11 may be about 50 % greater than that 100 of the tube of the tube and rod assembly so that there exists an annular clearance spaced between the tube and the inner surface of the sleeve where the

tube passes through the same 105 At its outer end the bush 11 with the end portion of the sleeve 15 encircling same, passes through an aperture in an exterially mounted bracket, 17 for the thermostat, said aperture receiving the rearward end 110 of the bush and assembled sleeve as a close sliding fit, this bracket 17 being preferably provided with a radially extending pinch screw 18 which serves to not only hold the thermostat in position but also in the case 115 of an electric cooking stove (as opposed to a gas stove) to form an earth continuity connection from the bush and the tube and rod assembly to the body of the cooking stove with which such bracket is electrically 120 connected. The rearward end of the sleeve 15 is held against one limb of the bracket 17 by means of a tongue cut from the end of the sleeve and bent back against the bracket as indi 125 cated at 19 in Figure 1. The length of the sleeve 15 is selected to enable the housing 12 of the thermostat to be spaced rearwardly from the back wall 14 of the oven which has an external heat 1330 785,057 i 735,057 barrier 20 (e g of thermal insulation) to any required extent sufficient to maintain the temperature within the housing below the desirable upper limit For example a sleeve length of about 2 inches will be found satisfactory in most cases. Furthermore, conductive transmission of heat from the wall of the oven to the bush through the material of the sleeve itself can be reduced by making the sleeve of thin metal for example 20 S W G so that the cross section of the conductive path is small. The forward end of the tube and rod assembly 10 is supported from the top wall I 1 of the oven by means of a "U" shaped bracket 21 of which the base, 22 is secured to the top wall 13 by means permitting it to be reversed end-to-end so as to position one dependent limb or the other nearer to the back 14 of the oven This is achieved by securing the base 22 of the bracket to the top wall 13 by self tapping screws 23 which pass through open-ended-slots 24 in the bracket 21 and which thus permit of reversal :5 of the bracket 21 after the thermostat has been removed by slackening off the screws 23 without completely removing them. The dependent limbs of this bracket are formed with respective holes 25 and 26 of differing appropriate diameters for example an inch and 5/1 of an inch End-to-end reversal of this enables the forward extremity of the thermostat tube 10 to be inserted into the holes of corresponding diameter and to be effectively supported by the bracket 21. The remaining limb of the bracket i e. that limb not supporting the particular thermostat tube in use constitutes a guard shielding the forward end of the tube and rod

assembly from inadvertent damage by contact with dishes as these are put into or taken out of the oven or are changed from one shelf to another within the oven.


4646 4650.output

Law