Basic Specification

The brakes have been designed for heavy industrial duty, and they comply with AISE requirements. They are suitable for use with the 400, 600 or 800 range of mill motors and they may also be used in conjunction with other equipment.

There are three types of brake, electro-magnetic, electro-hydraulic and hydraulic, each of which is available in six sizes to suit the following wheel diameters: 8, 10, 13, 16, 19 and 23 inches. The output torques range from 50 Ibf ft (68 Nm) to 4000 Ibf ft (5400 Nm).

The electro-magnetic and the electro-hydraulic brakes are spring applied and electrically released, which means they are inherently fail safe. Shunt brakes are available, with the nec-essary ancillary equipment, for operation on voltage ranges from 100V to 550V D.C. and 200V to 550V A.C. Series brakes are available for use in series with D.C. motor armatures for motor full load currents between 10 amperes and 928 amperes.

Features of Design

1. DustproofingMinimisesMaintenance • Outer armature strap seats on full sealing area • Inner dust seal is located between the inner armature and coil casting • Bellows type seal fitted to torque adjuster nut is effective when brake is ON or OFF

2. FrictionLinings Moulded lining material gives greater resistance to wear and fade without loss in brake efficiency. Longer life if bonded linings are used.

3. LiningAdjustments Positive locking of inner shoe adjustment ensures setting is not disturbed by vibration during use.

4. EasyTorqueAdjustment Simple torque adjustment to ease maintenance and eliminate maladjustment. Set by turning nut clockwise to positive stop and then anti-clockwise to required torque setting.

5. MagnetGapAdjustment Stops for ultra rapid application and reduces frequency of adjustment.

6. FastApplication Permanent air gap within armature improves application time of brake and ensures constant operation. Air gap requires no adjustment.

7. Terminals Sealed glands ensures coil remains dust-proof

8. LockedShoeBolts Shoe bolts are wired locked, in addition to spring washers to hold fast after installation and setting.

9. ArmatureHinge Well proven, rigid angle support and shoulder bolts mean greater reliability.

Drum Brakes / Type SM

8

2

3 4 6

1 1 1

9 5 7

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Brake Construction

The following description is mainly applicable to the electro-magnetic and electro-hydraulic types, but where relevant it also applies to the more simple hy-draulic version.

The design is robust and simple to provide a reliable brake requiring a minimum of maintenance.

Structural MembersThese are all made of iron or steel castings. The base has four plain hole fixings close to the shoe lever pivots. The electro-magnetic and electro-hydraulic brakes have a tapped hole in a machined pad to the rear of the magnet to provide additional support for the magnet assembly. The shoe levers pivot in knuckle joints which extend the width of the base and provide a large bearing surface to absorb braking thrust. The shoes are supported in cradles which allow them to align to the wheel rim during installation but they are then rigidly clamped to the lever to eliminate knuckle wear.

MagnetThe magnet consists of two similar cast steel arma-tures which, in conjunction with the coil, provide a powerful short stroke magnet system. The armatures pivot at their base in well proven rigid angle supports

Brake Operation

Electro-Magnetic BrakesWith the coil de-energised the torque spring forces the armatures apart. The outer shoe is pulled inwards onto the wheel via the pull rod connected to the outer armature. The inner shoe is pressed onto the wheel by the inner armature acting through the adjusting wedge. When the magnet is energised the two arma-tures are attracted together allowing both shoes to be lifted off the wheel.

The coils of shunt brakes are designed to release the brake at 80% of the line voltage and to hold the brake released down to at least 50% of the line volt-age. These figures apply when the coils are used with the required ancillary control gear. The coils of series brakes are designed to release the brake at 40% of the motor full load current and to hold the brake released down to at least 10% of the motor full load current.

Electro-hydraulic BrakesThe information given above for electro-magnetic brakes also applies to the electro-hydraulic brake, but these brakes have the additional feature of either hydraulic brake actuation or hydraulic release.

Hydraulic ApplicationThis version has a hydraulic cylinder incorporated in

the pull rod which allows the brake to be applied hydraulically when the brake is in the electrically released condition. The torque loading, applied hydraulically from a manually operated master cyl-inder, is variable depending on the force applied to the operating pedal, and this version of the brake is particularly useful on the long travel motion of cranes where close control of crane position is required. It is normally only fitted to continuously rated shunt brakes. Should the electrical power fail, the brake will be automatically applied.

Hydraulic ReleaseThis version also has a hydraulic cylinder incorporated in the pull rod. With the magnet de-energised, it al-lows the brake to be manually released. This is useful in the event of a power failure when a hoisted load needs to be lowered and for maintenance.

Hydraulic BrakesThese brakes do not have a magnet but have a hy-draulic cylinder incorporated in the tie bar. The brakes are for hydraulic application from a manually oper-ated master cylinder and therefore the brake torque is dependent on the manual force applied.

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Fig. 1

and shoulder bolts. Adjustable stops are provided which allow the residual magnetic gap to be in-creased to reduce brake application time. The adjust-able torque spring is contained between the two armatures and the torque is adjusted by the torque adjusting nut. The magnet is effectively protected against the ingress of dust by a wide strap across the machined outer surface of the armatures, ring seals between the coil and the inner poles of the armatures and a bellows seal beneath the torque adjustment nut.

CoilThe coil, of class B construction, is encapsulated in a sheet steel casing and is mounted separate from and between the two armatures.

LiningsLinings are bonded to the shoes as standard. They are made from non-asbestos base material which has a high coefficient of friction, low rate of wear and anti-face characteristics,

Lining Wear AdjustmentEach shoe is adjusted independently. The outer shoe is adjusted by a nut. The inner shoe is adjusted by a bolt operated sliding wedge. Both adjustments are locked by lock-nuts.

Dust Seal Strap

Armature

Torque Adjusting Nut

Bellows Seal

Terminal Cover

Torque Spring

CoilRingsealOiled Pads

Knuckle Joint

Base

Outer Shoe Lever

Shoe

Friction Lining

Outer Shoe Adjustment Nut Pull Rod Adjusting Bolt Wedge

Residual Magnetic Gap Adjustment Bolts

Electrical Control Equipment for Shunt Brakes

Resistance PanelsThese are fitted in series with coils operated from a D.C. supply to reduce the supply voltage to the rated voltage of the brake coil. Intermittently rated brakes operated from 100/115 volts do not require a series resistance. 19 and 23 in brakes (excepting those fit-ted with 100/115 volt coils) are controlled by a quick release relay panel which incorporates the necessary series resistances.

The wire-wound resistances are enclosed in a sheet steel ventilated wall fixing enclosure.

Rectifier PanelsThese are required for all shunt brakes operated from an A.C. supply. The panel incorporates a selenium bridge rectifier, a brake relay which switches the brake coil on the A.C. and D.C. side of the bridge rectifier and two rewirable fuses. Where necessary series dropper resistances are included on the panel except when a quick release relay is used.

The equipment is enclosed in a ventilated, sheet steel, wall fixing enclosure.

Metrosil UnitAs an optional extra an enclosed panel can be pro-vided to protect external insulated cables. The metrosil is rated at up to 600V D.C. and should be connected across the coil terminals.

Hydraulic Control Equipment

The hydraulic control equipment for hydraulic and electro-hydraulic brakes is normally arranged to operate one brake only and consists of:

• A master cylinder which may be of either 1 ¼” or 1 ½” diameter depending on the application. The master cylinder is attached to and operated by a foot pedal assembly which may have either a foot pedal or hand lever. The assembly may be mounted in a variety of ways as shown in Fig 4. All necessary pipe fittings are supplied with the assembly.

• A reservoir tank; which should be mounted above the master cylinder and the brake slave cylinder. The tank will be supplied complete with pipe fittings.

(Note: Brakes will also have all the necessary fittings sup-plied for them to be connected to the hydraulic tubing).5/16” outside diameter ‘Bundy’ hydraulic tubing is avail-able and should be ordered separately , noting that wherever a join in pipework is necessary a straight con-nector is required.

Effective bleeding of hydraulic systems is vital and if pipework has to be taken over obstacles, an inline bleeder assembly should be fitted at the highest point of potential air traps. Other versions are available as stand-ard as follows:• One brake operated from two pedals as shown in

Fig 5. The extra foot pedal and the auto changeover valve are included in the catalogue number.

• Two brakes operated from one pedal, as shown in Fig 6. The additional pipe fittings required are included on the master cylinder.

When operating two large brakes from one cylinder the brakes must be kept adjusted or the operating pedal movement will be excessive.

If the operator force required is considered excessive a small bore master cylinder is available to special order which will reduce the force by up to 50% of the figures quoted in the table, but the operator will need to be pumped.

To special order, up to four brakes may be operated from one pedal, but as above the operator will need to be pumped. Use hydraulic fluid Lockheed Super 105.

Ancillary Equipment

Hand ReleaseA hand release lever may be fitted to all electro-magnetic and electro-hydraulic application brakes. The hand release lever allows the brake to be released when no power is available for electrical release.

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Fig. 4 Alternative ways of mounting foot pedal assembly

Fig. 2

Fig. 3

Fig. 5 One brake, two pedals

Fig. 6 Two brakes, one pedal

B

R

RR BR1

BR2To brake solenoidcoil or QR relay

(Registor not required when used with QR relay)

B2R2 R1

C3 C1

C2 BB

QRR coil

Brake coilQRR

Economyresistance

D.C.supply

Use either ofthese interlockcircuits, not both

2

2

21

B1

21

CA.C.supply

B

R

RR BR1

BR2To brake solenoidcoil or QR relay

(Registor not required when used with QR relay)

B2R2 R1

C3 C1

C2 BB

QRR coil

Brake coilQRR

Economyresistance

D.C.supply

Use either ofthese interlockcircuits, not both

2

2

21

B1

21

CA.C.supply

Quick Release Relay PanelsThese are supplied with 19 in and 23 in shunt brakes. The circuit reduces the brake release and application times. At switch on, the full voltage input to the panel is applied to the brake coil to smartly release the brake. When the current has built up to a preset level above the brake release current the quick release re-lay contact opens and inserts the economy resistance, which reduces the brake coil current to a holding level and ensures that the brake is quickly applied when the supply is switched off.

The equipment is enclosed in a ventilated, sheet steel, wall fixing enclosure.

Electrical Control Equipment for Series Brakes

Series brake coils are connected directly in series with the armature of D.C. motors. No separate control equipment is required.

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Dimensions (mm) Dimensions (mm)

Size/wheel dia.A B C D E F G H J K8203 (8in)

178 83 73 284 17.5 5/8 BSF 94 98 392

10254 (10in)

213 102 79 306 17.5 5/8 BSF 100 122 433

13330 (13in)

251 146 114 325 20.6 3/4 BSF 140 171 498

16406 (16in)

308 191 137 321 27.0 1 BSF 165 222 543

19483 (19in)

337 235 165 375 27.0 1 BSF 200 270 645

23584 (23in)

403 298 203 397 33.3 1¼ BSF 241 337 737

Size/wheel dia.A B C D F H J L M N P S Weight (kg)203 (8in) 178 83 73 17.5 94 98 198 168 178 367 76 18

254 (10in) 213 102 79 17.5 100 122 243 203 211 422 89 30

330 (13in) 251 146 114 20.6 140 171 262 254 254 500 140 60

406 (16in) 308 191 137 27.0 165 222 306 311 308 583 165 80

483 (19in) 337 235 165 27.0 200 270 354 368 372 687 216 135

584 (23in) 403 298 203 33.3 241 337 416 457 435 797 279 195

M N Q R S T U V Weight (kg)168 399 354 240 76 400 464 3/4 in

Conduit64

203 441 408 271 89 456 462 1¼ in Conduit

91

254 514 494 329 140 545 598 1¼ in Conduit

173

311 565 576 379 165 624 675 1½ in Conduit

236

368 683 662 456 216 691 795 1½ in Conduit

397

457 803 772 519 279 816 968 2 in Conduit

595

Electro-magnetic and electro-hydraulic brakes Hydraulic brakes

Hand Release When Fitted

Hydraulic Cylinder When Fitted

G Hole

Conduit HoleV

FRONT VIEW SIDE VIEW PLAN

Min. headroom req. to operate

4 Holes F Dia.U

RNM

B

CFixings Fixings

C ED D

H HJ K

A. Dia

Common Terminals

19 & 23 inch Brakes Series Coils

Width of Shoes

S

Width of Shoes

S

Fixings

B approx.

152

91.4

A

102

11438

21 73 149 21

171

17.5

318

159

83

8364

137

Foot Pedal Size 203 305A 254 356B 305 368

47.6

47.6

3 Fixing Bolts

Reservoir Tank

73

67

38

4 Bolts 6.4

36.5

76

31.8 Master Cylinder

31.8 Master Cylinder Centre Line

222 fixings

38

Fixings 4 Holes F Dia.D

H H

D C

M N

P

B

J L

C

A. Dia

FRONT VIEW SIDE VIEW PLAN

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