after sir balandra for binding

7/23/2019 After Sir Balandra for Binding

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CHAPTER 1: INTRODUCTION

Construction of a building involves the use of corrugated bars or rods to make and

support columns and to create reinforcing bars to form the skeleton of a building.

Reinforcing bar is nothing but a square, rectangular or trapezoidal shaped rod which is

tied with the structural rod together at specific distance for strength improvement

purpose. Presently, these reinforcing bars are produced manually in small construction

sites in the Philippines. In the manual procedure, the operator makes all five bends

giving the corresponding strength for making one stirrup which results to less

productivity due to repetition. his kind of practice causes fatigue to labors which lowers

the efficiency of labors that in turn lowers the working efficiency of rod bending

operation.

o overcome this problem, the researchers aimed to provide a comfortable

production of stirrups which is cheaper. he pro!ect works on the mechanism of belts

powered by motor with a reducer connected to crank"rocker mechanism that will actuate

a shaft to cause motion on an oscillating table and bend the rod.

1.1 Statement of the Problem

#tirrup and lateral ties are important reinforcing elements for columns and beams

in buildings. Presently, these reinforcing elements are made manually which leads to

many drawbacks like lack of accuracy, low productivity and severe fatigue to the steel

man.

1



$ence, the researchers designed a machine that could lessen the hassle of the

manual process and increase the productivity.

1.2 Signifiane of the St!"#

he study was done to find solution on the problems encountered in the manual

production of the reinforcing bars. he pro!ect was designed based on the principle of

crank"rocker mechanism that would provide convenience to the steel man in forming the

stirrups and lateral ties in construction areas. he operator will !ust feed the rod to the

machine without applying e%treme force and e%posing the muscles in strenuous work.

he realization of the study would benefit the steel man who makes reinforcing bars

manually. he rectangular stirrup bending machine would lessen the hassle of the

manual process and increase the productivity.

1.$ Ob%eti&e' of the St!"#

1.$.1 (eneral Ob%eti&e

he researchers aimed to design and fabricate a rectangular stirrup bending

machine.

1.$.2 S)eifi Ob%eti&e'

&. 'esign a rectangular stirrup bending machine powered by an electric motor

utilizing a crank rocker mechanism(). *ake reinforcing bars with &).+ cm % )) cm and & cm % -& cm dimensions and

lateral ties of ) cm % ) cm and )) cm % )) cm out of &) mm rod.-. /valuate the performance of the designed rectangular stirrup bending machine in

terms of productivity compared to the manual making process.

2



1.* So)e an" Delimitation

his study covered the design and fabrication of the rectangular stirrup bending

machine including the testing of its performance through the determination of the average

time elapsed in completing one stirrup out of three trials. he specified dimensions are

&).+ cm % )) cm, & cm % -& cm, ) cm % ) cm and )) % )) cm. he ma%imum

diameter of the rod is &) mm for all dimensions. he special feature that guides the

length of the stirrup is fi%ed on the table. he ma!or components include an electric

motor, ) pulleys, belt, speed reducer, crank plate mechanism, oscillating round table and

the frame.

CHAPTER 2: RE+IE, O- REATED ITERATURE

2.1 Rebar

3



Rebar 0short for reinforcing bar1, also known as reinforcing steel, reinforcement

steel and colloquially in 2ustralia as reo, is a steel bar or mesh of steel wires used as a

tension device in reinforced concrete and reinforced masonry structures to strengthen and

hold the concrete in tension. Rebar3s surface is often patterned to form a better bond with

the concrete 0*errit, 4., et. al., &55+1.

2ccording to Padole in )&, stirrups or lateral"ties are rectangular, square or

circular shaped reinforced element made out of mm, 6 mm or & mm steel bar. In order

to safeguard the structure against failure by diagonal tension, reinforcement is required.

his reinforcement is called #hear reinforcement which is provided by the stirrups.

he important functions of a stirrup are "

&. to hold and support horizontal and vertical mild steel plain bar(

). to provide reinforcement and rigidity to column and beams(

-. to take shear force in horizontal beam structures as well as vertical columns(7. to avoid buckling of long slender column or avoid sagging of horizontal beam(

and,+. to provide proper anchorage which in turn safeguards the structure against

horizontal forces occurring due to wind, earthquake, etc.

2.2 /en"ing

2.2.1 0an!al Stirr!) /en"ing

Presently, stirrups are made manually as shown in figure ).).&. In this process

initially, as per the required size of the stirrup i.e. perimeter, stirrup wire or *.#. round

bar of mm or 6 mm are cut. he operator uses a wooden block as a platform for

4



bending on which three nails are fi%ed, around which the bending takes place. he

stirrup wire is passed horizontally between the nails up to the chalk mark and then the

operator bends the bar using a lever like hand"tool 3daag3, about the nail through an angle

of 5 degree. he chalk marks are made as per the size of the stirrups. 2fter completing

one bend, the operator lifts and repositions the bar for the ne%t bending. In this way the

operator makes all five bends to make one stirrup 08analkar, 2.8. 9 Padole, P.*., &5551.

he manual stirrup making process suffers from the drawbacks like lack of

accuracy, low productivity and severe fatigue in the operator. he construction worker

not only sub!ects his hands to hours of repetitive motion 0i.e. performing bending

operation to produce stirrup1 but also sometimes suffers internal in!ury in his body organ

i.e. disorder carpal tunnel syndrome C#, slipped disc problem etc. 0#heth #., et. al.,

)&-1.

Figure 2.2.1 Manual stirrup bending

2.2.2 0ehaniation

2ccording to 8analkar on &555, mechanization is providing human operators with

machinery that assists them with the muscular requirements of work or displaces

muscular work. In some fields, mechanization includes the use of hand tools. In modern

usage, such as in engineering or economics, mechanization implies machinery more

5



comple% than hand tools and would not include simple devices such as an un"geared

horse or donkey mill. 'evices that cause speed changes or changes to or from

reciprocating to rotary motion, using means such as gears, pulleys or sheaves and belts,

shafts, cams and cranks, usually are considered machines. 2fter electrification, when

most small machinery was no longer hand powered, mechanization was synonymous

with motorized machines.

2.$ Relate" St!"ie' of Stirr!) /en"ing

he system that was proposed by the #ri :rishna College of /ngineering 9

echnology is the bending of square and circular stirrups. he rod is bent with the help

of hydraulic force, because the power of hydraulics is very large the main aim of the

pro!ect is to increase the productivity so with the help of hydraulic force it can bend -"

rods depending upon the diameter. he drawbacks in the older machines are rectified. If

the rod is placed for bending in the e%isting system, the operator repositions the rod for

every bend, but in this system once the rod is placed it does not need to be repositioned

for all bends. his is done by a special attachment by coupling the pinion wheel of a rack

and pinion set to a freewheel, the function of the freewheel is to change the position of

the table to 5 degrees. ;hen the hydraulic cylinder is in the forward stroke the

freewheel slips and holds the fi%ture table at the time the rod is bent. In return, the stroke

of the cylinder rotates the pinion which is connected to the freewheel turns the table to 5

degrees 0$anoof, et. al., )&71.

2utomatic #tirrup <ending *echanism 02#<*1 using the principles of hydraulic

and electronics has been developed. 2#<* system was incorporated with piston

6



cylinder arrangement, arrangement of feed rotors run by wiper motor to feed the rods

automatically and an IR 0Infrared1 sensor to sense the presence of rod under the

controlling action of microcontroller. In this mechanism, bending of the rod has been

taken by piston"cylinder arrangement while progressing of the rod in the forward

direction with the aid of two rollers using a wiper motor. his process continues until the

complete stirrup was made and the sensor is activated as per the necessity 0#heth,#., et.

al., )&-1.

2.* THE CO0PONENTS

2.*.1 /elt'

<elts made of leather, rubber, or woven fabrics are flat and thin, and run on

pulleys nearly cylindrical with smooth surfaces. 4lat belts are used to connect shafts as

much as - ft apart. <elts may be run economically at speeds as high as 7+ fpm. <elts

are also made with 8"shaped cross section to be used on grooved pulleys. 8"belts are

usually used for connecting shafts which are less than &+ ft apart. #peed ratios up to = to

& and belt speeds up to + fpm may be used 0'oughtie and >ames, &5+71.

2.*.2 0otor' an" Dri&er'

?nless manually operated, a mechanism will require some type of driver device to

provide the input motion and energy. If the design requires a continuous rotary input

motion, such as @rashof linkage, a slider"crank or a cam"follower, then a motor or engine

is the logical choice. *otors come in wide variety of types. he most common energy

7



source of a motor is electricity, but compressed air and pressurized hydraulic fluid are

also used to power air and hydraulic motors, gasoline or diesel engines are also good

alternative. If the input motion is translational, as is common in earth"moving equipment,

then a hydraulic or pneumatic cylinder is usually needed 0Robert A. Borton, )&1.

CHAPTER $: CONCEPTUA -RA0E,OR

$.1 in3age

2 linkage consists of a number of pairs of elements connected by links. If the

combination is such that relative motion of the links is possible, and the motion of each

8



piece relative to the others is definite, the linkage becomes a kinematic chain. If one of

the links of a kinematic chain is fi%ed, then the chain becomes a mechanism.

In order that a linkage may constitute a kinematic chain, the number of fi%ed

points whose motions are determined by means outside the particular linkage in question,

it must bear such a relation to the total number of links that the linkage may form a four"

bar linkage 0'oughtie and >ames &5+71.

$.2 -o!r4bar in3age

In studying the motion of a mechanism by applying the laws of the four"bar

linkage the first step is always to identify the four"bar linkage or chain of four"bar

linkages. It must be borne in mind that each line representing a link is a part of some

rigid body. he line of centers is on a body assumed to be fi%ed( the center lines of the

cranks are on rigid bodies turning about a%es attached to the fi%ed body, and the center

line of the coupler is on a rigid body connected to each crank by either a turning pair or a

sliding pair.

o identify the links it is best, usually, to start at the driving member and to find

the fi%ed a%is about which this member is turning. his member, being a rigid piece

turning about a fi%ed a%is, is a crank. 'etermine the fi%ed a%is and the rigid piece turning

about it which receives its motion from the driver either by direct contact or through one

intermediate connector. hus the two cranks of a four"bar linkage are found. he

member to which the fi%ed a%es are attached is the fi%ed link, and the straight line !oining

the two fi%ed a%es is the line of centers. If the driving crank imparts motion to the driven

crank through an intermediate connector, the connector is the coupler or connecting rod,

9



its center line being the line !oining the a%es of the pin !oints by which the coupler is

connected to the cranks. he center line of each crank is the line !oining the fi%ed a%is to

the point of connection with the coupler 0'oughtie and >ames &5+71.

$.$ Relati&e 0otion of the in3' in a -o!r4/ar in3age

#ince the motion of the links( relative to some links assumed to be fi%ed, is not

changed if motion is imparted to that link, it follows that the motion of any link, relative

to any other link of the linkage, is the same whichever link is fi%ed. In other words, the

relative motions of the links of a four"bar linkage are independent of the fi%edness of the

link 0'oughtie and >ames, &5+71.

$.* Ang!lar S)ee" Ratio of in3'

<ecause of its importance in the analysis of linkages, the law applying to the

angular speed of the cranks should be restated as follows the angular speeds of the two

cranks of a four"bar linkage are inversely as the lengths of the perpendicular or any two

parallel lines drawn from the fi%ed centers to the center line to the connecting rod( also,

inversely as the distances from the fi%ed centers to the point of intersection of the center

line of the connecting rod and the line of centers 0'oughtie and >ames, &5+71.

$.5 Re'earh De'ign

<elts and chains represent the ma!or types of fle%ible power transmissionelements. his study illustrates where belts, gear drives, and chains are

each used to best advantage. Rotary power is developed by the electric

motor, but motors typically operate at too high speed and deliver too lowtorque to be appropriate for the final drive application. Remember, for a

given power transmission, the torque is increased in proportion to the

amount that rotational speed is reduced. #o, some speed reduction is

desirable. he high speed of the motor makes belt drives somewhat ideal

10



for that first stage of reduction. 2 smaller drive pulley is attached to the

motor shaft, while a larger diameter pulley is attached to a parallel shaft

that operates at a correspondingly lower speed. Pulleys for belt drives arealso called sheaves. $owever, if very large ratios of speed reduction are

required in the drive, gear reducers are desirable because they can

typically accomplish large reductions in a rather small package. heoutput shaft of the gear"type speed reducer is generally at low speed and

high torque. If both speed and torque are satisfactory for the application,

it could be directly coupled to the driven machine. $owever, because gear reducers are available only at discrete reduction ratios, the output must

often be reduced more before meeting the requirements of the machine.

2t the low"speed and high"torque condition, chain drives become

desirable. he high torque causes high tensile forces to be developed inthe chain. he elements of the chain are typically metal, and they are

sized to withstand the high forces. he links of chains are engaged in

toothed wheels called sprockets to provide positive mechanical drive,

desirable at the low"speed, high"torque conditions. In general, belt drivesare applied where the rotational speeds are relatively high, as on the first

stage of speed reduction from an electric motor or engine. he linear speed of a belt is usually )+ to + ftDmin which results in relatively

low tensile forces in the belt. 2t lower speeds, the tension in the belt

becomes too large for typical belt cross sections, and slipping may occur between the sides of the belt and the sheave or pulley that carries it. 2t

higher speeds, dynamic effects such as centrifugal forces, belt whip, and

vibration reduce the effectiveness of the drive and its life. 2 speed of 7

ftDmin is generally ideal. #ome belt designs employ high"strength,reinforcing strands and a cogged design that engages matching grooves in

the pulleys to enhance their ability to transmit the high forces at low

speeds 0*ott, )71.

he design of the rectangular stirrup bending machine uses the power of a motor

as its driving force. he rod is bent by a bender fi%ed to a circular oscillating table with

the help of a stationary post at the center of the table. he oscillating motion is caused by

the crank mechanism in which the linkage is connected beneath the roundtable. he

crank that is pinned with a connecting rod that holds the linkage is fi%ed at a plate which

is connected to a pulley by a shaft. he speed of the pulley is designed based on the

operatorEs comfort. his is to create enough pacing of the bending procedure for the

11



operator to reposition the rod. his is done with the use of a pulley connected from a

motor coupled to a reducer as shown in figure -.+.&.

&" *otor )" Pulley0driver1

-" Pulley0driven17" Reducer

+" Crank plate" Fscillating table

7- Figure 3.5.1 Machine main parts with label

12



64 $.7 De'ign Cal!lation

84

194 $.7.1 Cal!lation of the 0aim!m /en"ing -ore

&&" he design is based on the grade 7 2&+ reinforce bar, &)mm in

diameter minimum yield strength of 7, psi 0)=+ *Pa1.

&)" 4rom G#trength of *aterialsH by Pytel and #inger, &56=, page &-+

&-"

&7" σ b=

M × y

I

&+";here

&" σ b=Bending Stress

&=" M = Moment = F ×l

&6" y= Distancce=

d

2

&5"

d¿¿¿4π ¿

I = Inertia=¿

)"hus,

)&"

d

¿¿¿4π ¿¿

σ b= F × l ×

d

2

¿

))" aken minimum yield strength of 7, psi 0)=+ *Pa1 and a length equal to 7=

mm, from enter to center distance between the post and bender.

)-" σ b=275 N

mm2

)7" l=47mm

13



)+"

12mm¿¿¿ 4π ¿¿

275 N

mm2=

F ×47mm × 12mm2

¿

)"

)=" F =982.1611 N

)6" *ultiply the load by three thus,

)5" F =982.1611 N ×3

-" F =2946.4833 N

-&"

$24 $. 7. 2 Cran3 Ro3er 0ehani'm

--" <ased from the book of Robert A. Borton, 'esign of *achinery, )&,

-7" #cale & cm ) cm

-+" Futput angle J 5⁰

-"

14

.24



-="

-6"

-5"

7"

7&"

7)"

43-

44- Figure 3.6.2.1 Crank !cker Mechanism "iagram

15

980



& he output linkO

4B

in both e%treme positions,B

1 9 B

2 were drawn to

subtend the desired angle of motion which is 5⁰. Aink 7 is drawn such that the

two e%treme positions each make an angle of 7+⁰ to the vertical.) Chord

B1

B2 is then traced and e%tended to the left.

- 'istance A

1B

1 along the e%tended lineB

1B

2 is then laid out equal to the

length of link -.

7 Aine segmentB

1B

2 is bisected and the length of the bisected line is then laid

out from point A

1 along the e%tended line B

1B

2 . he endpoint is marked

O2 and a circle is drawn with radius

O4 A

1 with center at O

2 .

+ he line is then e%tended connecting the link - to the radius O

4 A

2 .

7+" aken dimensions

7" Crank Plate hickness,

T cp=12.7mm

7=" Crank Plate 'iameter, Dcp=17.96 cm

76"

$.7.$ Conneting Ro"

*84 he coupler is designed to withstand a ma%imum load of

2946.4388 N . Its length is equal to -.76 cm 0refer to design calculation of

crank"rocker mechanism1 and is made of 2I#I &7 $ot"Rolled #teel with a yield

strength of )5 *Pa, modulus of elasticity / J )= @Pa, and is pinned"pinned

end fi%ity :J&. 0refer to *achine /lements in *echanical 'esign, - rd /dition by

Robert A. *ott, &555, 2ppendi% - 'esign Properties of Carbon and 2lloy #teels,

16



fig."+ ransition #lenderness ratio vs. Kield #trength for #teel on page &51. ?se

factor of safety BJ-.+" he design of the connecting rod is adopted from *achine

/lements in *echanical 'esign, -rd

/dition by Robert A. *ott, &555.+&" 'esign he connecting rod is designed as a column because it is a relatively long,

slender compression member.

+)" aken the allowable load Pa equal to 2946.4388 N

+-" C!lumn c!nstant# C c , /quation "7, page &5- 0*ott, R.A., &5551,

+7" C c=√ 2π 2

S y

++";here

+" =207×109 Pa

+=" S y=290×106 Pa

+6" C c=√ 2π 2(207×10

9 Pa)

290×106 Pa

+5" C c=119

" 2ssume column is long thus,&" $uler%s $&uati!n# /quation "6, page ) 0*ott, R.A., &5551,

)" I = N Pa( !")2

π 2

-";here

7" I =B #

3

12 02ppendi% &, Rectangular cross"section1

+" aken the value of < is twice the value of $ in equation,

" B=2 # ##

="$ence,

6" I =2 # 4

12

5" #o,

17



="

!"¿¿

N Pa ¿¿

12¿

¿ # =4√ ¿

71- $''ecti(e )ength# *)# /quation "), page &5) 0*ott, R.A., &5551,

72- !"=1.0×0.3048m

73- !"=0.3048m

=7" 2nd,

=+"

0.3048m ¿2

3×(2946.4388 N )¿¿

12¿¿ # = 4√ ¿

=" # =7×10−3

m

==" # =7mm

=6" herefore,

=5" B=2 #

6" B=2 (7mm )

6&" B=14mm

6)" he final cross"sectional dimension is taken to be,

6-" # =12.7mm

67" B=30mm

6+" adius !' +,rati!n# r# /quation "&, page &5& 0*ott, R.A., &5551,

6" r=√ I

A

6=";here

66" I = Inertia

65" A=Cross sectional area

90-

5&"

18

B=30mm

# =12.7mm



5)"

5-"

57"

5+" I =B #

3

12 02ppendi% &, Rectangular cross"section1

5" I =0.030m×(0.0127)3m

3

12

5=" I =5.12×10−9

m4

56" A=B × #

55" A=0.030m×0.0127m

&" A=3.81×10−4

m2

&&" hus

&)" r=√ 5.12×10−9

m4

3.81×10−4

m2

&-" r=3.6658×10−3

m

&7" lenderness ati!# !"

r , /quation "-, page &5- 0*ott, R.A., &5551,

&+" !"

r =

0.3048m

3.6658×10−3

m

&" !"

r =83.1469

&=" #ince !"

r <C

cthus the column is short. ?se the >.< >ohnson formula to

compute the critical load.

&6"&5" ./ !hns!n F!rmula# /quation "=, page ) 0*ott, R.A., &5551,

&&" Pcr= A s y 1−s

y

( !"

r )

2

4 π 2

&&&" Pcr=(3.81×10

−4m

2 )(290×106 Pa)[1−(290×10

6 Pa)(83.1469)2

4 π 2(207×10

9 Pa) ]

&&)" Pcr=83,382.9028 N

19



&&-" his is the critical buckling load. #ince Pa< Pcr the connecting rod is

safe against critical buckling load.

114-

$.7.* /en"er an" Po't

&&+" @iven

&&" F =2946.4833 N

&&=" aken a deflection of &mm

&&6" $ =¿

& mm

&&5" "=50mm

&)" 4rom *achine /lements in *echanical 'esign 7 th /dition by

Robert A. *ott, &555, able 2&7")

&)&" $ =−% "

3

8 I

&))" ;here

&)-" %=

F

"

&)7" I =π D

4

64&or circ'lar section

&)+"$ = −% "

3

8 π D

4

64

&)" 1mm=

−2946.4833 N

50mm (50mm)3

8(207×106 Pa)

π D4

64

&)=" D=0.070mm

&)6"&)5" 2 diameter of 0.070mm will cause a deflection of &mm

therefore a design to prevent deflection of the rod and bender post diameter of

DB=¿ -6 mm and

D PO=¿)+.7 mm will be used respectively.

20



&-"

131-

132-133-

134-

135-136-

137-

130-13-

14- Fi

gu

re

3.6.4 hear and m!ment diagram !' bender and p!st

1*14 $.7.5 S)ee" Cal!lation

1*24 he designed speed of the oscillating table is &=.) rpm. he

designed speed was based on the human capacity to feed the rod continuously for

the bending process. hus, in order to achieve the designed speed, from the

speed of the motor which is &=) rpm, speed ratio of -+ of pulleys and &

speed reducer were used.

&7-" #olving the angular speeds at the end and start of the gear trains,

&77" N p1

=1720 rpm

&7+" N p2

=1032 rpm

&7"

&7="

21



&76" able -..+ ypical Power ransmission /fficiencies

1*84

1594 0ahine

1514

1524

15$4 T#)ial

Effiien#

&+7" 8"belt 'rives &++" 5+L

&+" iming <elt 'rives &+=" 56L&+6" Poly"8 or Ribbed <elt 'rives &+5" 5=L

&" 4lat <elt drives, Aeather or Rubber

&&" Bylon Core

&)" 56L

&-" 56L to

55L

&7" 8ariable #peed, spring loaded, wide range

&+" 8"belt 'rives

&" Compound drive

&="

&6" 6L to

5L&5" =+L to

5L

&=" Cam"reaction drive &=&" 5+L

&=)" $elical @ear Reducer &=-" #ingle"stage

&=7" wo"stage

&=+"&=" 56L

&==" 5L

&=6" ;orm @ear Reducer &=5" && ratio

&6" & ratio

&6&"&6)" 6L

&6-" 6)L

&67" Roller Chain &6+" 56L

&6" Aeadscrew, deg heli% angle &6=" +L to6+L

&66" 4le%ible Coupling, shear"type &65" 55LM

1894 $.7.7 De'ign of P!lle# an" /elt ength

1814

&5)" he force required to the rod is2946.4833 N based on the

ma%imum bending solved above.

&5-" 4rom G#trength of *aterialsH by Pytel and #inger, &56=, /quation -"-,

page 5

&57" P=2 πTN

&5+" T = F × d

22



&5" ;hered=distance¿ t(e radi's o& t(e center post ¿t(e radi's0.047m

&5=" hus,

&56"

0.047m

T =(2946.4833 N )¿ 1

&55" T =138.485 N ) m

)" hen,

)&" P=2 πTN

))"

1min

60sec

P=2 π (138.485 N * m)(17.2 re+

min )¿

1

)-" P=249.4364,

)7" P=249.4364, ×

1(p

746,

)+" P=0.3344 (p

)" o get the power transmitted in the reducer,

)=" &&iciency= Po't

P¿

)6" ;here,

)5" &&iciencyred'cer=82

)&"

)&&" hus,

23



)&)" P -=

P

&&iciency

)&-" P -=

249.4364,

0.82

)&7" P -=304.1907, =0.4078(p

)&+" he power transmitted by the reducer is equal to the power at the

Pulley ),

)&" o get the power transmitted in the pulley &,

)&=" &&iciency= Po't

P¿

)&6" ;here,

)&5" &&iciency. −belt =95

))"

))&" hus,

)))" P P1=

P P2

&&iciency

))-" P P1=

304.1907,

0.95

))7" P -=320.2007, =0.4292(p

))+" N p1=1720 rpm

))" N p2

=1032 rpm

))=" 4rom able &="&), 0<udynasNBisbett #higleyEs *echanical

/ngineering 'esign, 6th /dition, ), page 66&1, <elt #ection 2 with a sheave

diameter of - inches is best for 0.4292 horsepower rating.

))6" hen,

D P1

D P2

=3

5

24



))5" D P2

= D P1 ( -atio )

)-" D P2

=3∈( 53 )

)-&" D

P2

=5∈¿

)-)" hus, the diameter of pulley & is =.) cm and pulley ) is &).= cm.

)--" #olving for the length of belt, 0<udynasNBisbett #higleyEs

*echanical /ngineering 'esign, 6th /dition, ), page 661

)-7" ;here, C J &7

)-+" "c=2C +π ( D P1+ D P2)

2+( D P2− D P1)

2

4C

)-"

3∈+5∈¿¿

5∈−3∈¿¿¿2¿¿

π ¿ "c=2(14)+¿

)-=" "c=40.6378∈¿

)-6" ?se the standard value for the belt length, "c=41∈¿

J &7.&7

cm

)-5"

2*94 $.7.; Shaft "e'ign

2*14 Shaft <ith o'illating table

)7)" *aterial 2I#I &7 $ot"rolled

)7-" he properties of the specified steel are from the 2ppendi% - of the book

of Robert A. *ott *achine /lements in *echanical 'esign, &555.

)77" s'=496 MPa

)7+" s y=290 MPa

25



)7" elongation=18

)7=" he /ndurance #trength from 4igure +"5, page &+& 0*ott, R.A, &5551,

sn=175 MPa

)76" he size factor from 4igure +"6, page &+& 0*ott, R.A, &5551 /

C S=0.8

)75" he design reliability is . 55 then the reliability factor

)+" from able +"), page &+7 0*ott, R.A, &5551 / C r=0.81

)+&" Computing for the modified /ndurance #trength

)+)" s0 n=sn C SC -

)+-" s0 n=175 MPa(0.8)(0.81)

)+7" s0 n=113.4 MPa

)++" he 'esign 4actor is taken to be BJ)

)+" 'esigned #tresses, page & 0*ott, R.A, &5551

)+=" σ d=s

0 n

N

26



)+6" 1 d=0.577 s y

N

)+5" hen,

)" σ d=

113.4 MPa

2

)&" σ d=56.7 MPa

))" 2nd,

)-" 1 d=0.577(290 MPa)

2

)7" 1 d=83.665 MPa

)+" hen is ! t taken to be 1.5

)" Computing for the torque in the shaft,

)=" P=2 πTN

)6" T =

P

2 πN

)5" T =

249.4364,

2 π (17.2/60)

)=" T =138.485 N −m

27



)=&" #olving for *oment, *

)=)" 4rom equation &)"), page 766 0*ott, R.A, &5551,

)=-" σ = M

S

)=7" M =σS

)=+" ;here the rectangular section modulus #,

)=" S=2 p2

)==" 2nd from equation &)")&, page 766 0*ott, R.A, &5551,

)=6" 1 d=

T

2 p

)=5" hen the polar section modulus 2 p ,

)6" 2 p=

T

1 d

)6&"

2 p=138485 N −mm

83.665 N

mm2

)6)" 2 p=1655.232mm3

)6-" 2nd section modulus is,

28



)67" S=

1655.232

2

)6+"

S=827.616 mm3

)6" hen,

)6=" M =σS

)66" M =56.7 MPa(827.616mm3)

)65" M =46925.832 N −mm

)5" hus from equation &)")7, page 765 0*ott, R.A, &5551,

)5&" D={32 N

π √( ! t M

s0 n )

2

+3

4 ( T

s y )2}

1 /3

)5)" D=[ 32(2)π √( 1.5(46925.832)113.4 )2

+3

4 ( 138485290 )2

]1 /3

)5-" D=24.768mm

)57" 4rom Chapter &7 of the book of @upta and :hurmi, )+, page

+-&, the standard size of transmission shaft starts from )+ mm.

)5+" hen the shaft diameter is considered to be,

2874 DS=25.4mm

29



28;4

2864 -or 'haft <ith the ran3 )late: Same material

)55" 4rom *achine /lements in *echanical 'esign by Robert A. *ott, &555.

-" s'=496 MPa

-&" s y=290 MPa

-)" elongation=18

--" sn=175 MPa

-7" he torque is equal to &-6.76+ N −m

-+" #olving for *oment, *

-" 4rom equation &)"), page 766 0*ott, R.A, &5551,

-=" σ =

M

S

-6" M =σS

-5" ;here the rectangular section modulus #,

-&" S=2 p

2

30



-&&" 2nd from equation &)")&, page 766 0*ott, R.A, &5551,

-&)" 1 d=

T

2 p

-&-" hen the polar section modulus 2 p ,

-&7" 2 p=

T

1 d

-&+" 2 p=

138485 N −mm

83.665 N

mm2

-&" 2 p=1655.232mm3

-&=" 2nd section modulus is,

-&6" S=1655.232

2

-&5" S=827.616 mm3

-)" hen,

-)&" M =σS

-))" M =56.7 MPa(827.616mm3)

31



-)-" M =46925.832 N −mm

-)7" hus from equation &)")7, page 765 0*ott, R.A, &5551,

-)+" D={32 N

π √( ! t M

s0 n )

2

+3

4 ( T

s y )2}

1 /3

-)" D=[ 32(2)π √( 1.5(46925.832)113.4 )2

+3

4 ( 138485290 )2

]1 /3

-)=" D=24.768mm

-)6" 4rom Chapter &7 of the book of @upta and :hurmi, )+, page


-)5" hen the shaft diameter is considered to be,

$$94 DS=25.4mm

$$14

$$24 Sol&ing for the 'haft "iameter at the 5 inhe' )!lle#: Same material

---" 4rom *achine /lements in *echanical 'esign by Robert A. *ott, &555

--7" s'=496 MPa

--+" s y=290 MPa

32



--" elongation=18

--=" sn=175 MPa

--6" 4rom the calculation of power between reducer considering the efficiency

of reducer

--5" 4rom the ypical power transmission table,

-7" he reducer efficiency is 6)L then,

-7&" P -=

P

&&iciency

-7)" P -=

249.4364,

0.82

-7-" P -=304.1907,

-77" hen solving for the torque at the + inches pulley,

-7+" P=2 πTN

-7" T =

P

2 πN

-7=" T =

304.1907,

2 π (1032/60)

-76" T =2.8147 N −m

-75" #olving for *oment, *

33



-+" 4rom equation &)"), page 766 0*ott, R.A, &5551,

-+&" σ =

M

S

-+)" M =σS

-+-" ;here the rectangular section modulus #,

-+7" S=2 p

2

-++" 2nd from equation &)")&, page 766 0*ott, R.A, &5551,

-+" 1 d=

T

2 p

-+=" hen the polar section modulus 2 p ,

-+6" 2 p=

T

1 d

-+5"

2 p=2814.7 N −mm

83.665 N

mm2

-" 2 p=33.6425mm3

-&" 2nd section modulus is,

34



-)" S=

33.6425

2

--"

S=16.8213mm3

-7" hen,

-+" M =σS

-" M =56.7 MPa(16.8213mm3)

-=" M =953.7677 N −mm

-6" hus from equation &)")7, page 765 0*ott, R. A, &5551,

-5" D={32 N

π √( ! t M

s0 n )

2

+3

4 ( T

s y )2}

1 /3

-=" D=[ 32(2)π √( 1.5 (953. 7677)113. 4 )2

+3

4 (2814.7

290 )2

]1/3

-=&" D=6.7594mm

-=)" 4rom Chapter &7 of the book of @upta and :hurmi, )+, page


-=-" hen the shaft diameter is considered to be,

$;*4 DS=25.4mm

35



-=+"

$;74 Sol&ing for the 'haft "iameter at the motor: Same material

-==" 4rom *achine /lements in *echanical 'esign by Robert A. *ott, &555.

-=6" s'=496 MPa

-=5" s y=290 MPa

-6" elongation=18

-6&" sn=175 MPa

-6)" 4rom the ypical power transmission table,

-6-" he pulley efficiency is 5+L then,

-67" P P1=

P P2

&&iciency

-6+" P P1=

304.1907,

0.95

-6" P -=320.2007,

-6=" hen solving for the torque at the motor,

-66" P=2 πTN

36



-65" T =

P

2 πN

-5" T =

3202007,

2 π (1720/60)

-5&" T =1.7777 N −m

-5)" #olving for *oment, *

-5-" 4rom equation &)"), page 766 0*ott, R.A, &5551,

-57" σ =

M

S

-5+" M =σS

-5" ;here the rectangular section modulus #,

-5=" S=2 p

2

-56" 2nd from equation &)")&, page 766 0*ott, R.A, &5551,

-55" 1 d=

T

2 p

7" hen the polar section modulus 2 p ,

37



7&" 2 p=

T

1 d

7)"2 p=

1777.7 N −mm

83.665 N

mm2

7-" 2 p=21.2313mm3

77" 2nd section modulus is,

7+" S=

21.2313

2

7" S=10.6257mm3

7=" hen,

76" M =σS

75" M =56.7 MPa(10.6257mm3)

7&" M =602.4772 N −mm

7&&" hus from equation &)")7, page 765 0*ott, R.A, &5551,

7&)" D={32 N

π √( ! t M

s0 n )

2

+3

4 ( T

s y )2}

1 /3

38



7&-" D=[ 32(2)π √( 1.5(602.4772)113.4 )2

+3

4 ( 1777.7290 )2

]1 /3

7&7" D=5.7996mm

7&+" 4rom Chapter &7 of the book of @upta and :hurmi, )+, page


7&" hen the shaft diameter is considered to be,

*1;4 DS=25.4mm

7&6"

*184 $.7.6 O'illating Table

7)" he dimension of the rotating table is based on the length of the

rocker and the diameter of the post.

7)&" hus

7))" Fscillating able 'iameter, Dro=20cm

7)-" Fscillating Rotating able hickness, T ro=1

2∈¿1.27 cm

*2*4

*254 $.7.8 -rame

7)" he dimensions of the frame is taken to be,

7)=" 4rame hickness,T & =

1

4∈¿

¿0.635 cm

7)6" 4rame Aength, "& =¿ ++ cm

7)5" 4rame ;idth,, & J 7+ cm

39



7-" 4rame $eight, # & J 6) cm

7-&"

7-)"

7--"7-7"

7-+"

7-"7-="

7-6"

7-5"77"

77&"

77)"

77-"777"

77+"

77"77="

776"

775"7+"

7+&"7+)" able -. *aterial #pecifications 04rom the calculation1

7+-"

7+7" 0

ATERI

AS

7++"

*574

*5;4 SPE

CI-ICATI

ONS

*564

*584

*794

S=0

/

O

*714

*724

U

*7$4

*7*4 C

ACU

ATED

+AUE

S

*754

*774

*7;4

STAND

ARD

+A

UES

76" *

otor

75" Pow

er Rating

7="

P

7=&"

h

7=)"

0.5289

7=-"

)

7=7" P

ulley &

7=+" 'ia

meter

7="

D1

7=="

c

7=6" =

.)

7=5"

=.)

76" Pulley )

76&" 'iameter

76)" D

2

76-"c

767" &).=

76+"&).=

76" <

elt

76=" <elt

Aength

766"

"B

765"

c

75" &

.6

75&"

&.6

75)" R 75-" #pee 757" 75+" 75" " 75="

40



educer d ratio " &

756" C

rank

755" Cran

k hickness

+"

T cr

+&"

m

+)"

1

+-"

&

++" Cran

k Aength

+"

"cr

+="

c

+6"

8.98

+5"

8.98

+&" C

rank

Plate

+&&" Cran

k Plate

hickness

+&)"

T cp

+&-"

m

+&7"

12.7

+&+"

&).=

+&=" Cran

k Plate

'iameter

+&6"

Dcp

+&5"

c

+)"

17.96

+)&"

17.96

+))" C

oupler

+)-" Cou

pler

hickness

+)7"

#

+)+"

m

+)"

7

+)="

&).=

+)5" Cou

pler Aength

+-"

"co

+-&"

m

+-)"

0.3048

+--"

0.3048

+-+" Cou

pler ;idth

+-"

B

+-="

m

+-6"

14

+-5"

-

+7" <

ender

+7&" <en

der

'iameter

+7)"

Db

+7-"

m

+77"

0.07

+7+"

38

+7=" <ender Aength

+76"

"b

+75"m

++"

50

++&"

50

++)"

++-" P

F#

++7" Post

'iameter

+++"

D p

++"

m

++="

0.07

++6"

25.4

+" Post

Aength

+&"

" p

+)"

m

+-"

50

+7"

50

++"

+" F

#CIAA

2IB@

2<A/

+=" Rota

ting able

'iameter

+6"

Dro

+5"

c

+="

20

+=&"

20

+=-" Rota

ting able

hickness

+=7"

T ro

+=+"

c

+="

1.27

+=="

1.27

+=6"

+=5" 4

+6" hic

kness

+6&" +6)"

c

+6-" +67"

41



R2*/

+6" Aeng

th

587-

"&

+66"

c

+65" +

+

+5"

++

+5)" ;idt

h

593-

, &

+57"

c

+5+" 7

+

+5"

7+

+56" $eig

ht

599-

# &

"

c

&" 6

)

)"

6)

79$4

79*4

7954 CHAPTER *: 0ETHODOO(=

7974

79;4 *.1 Data (athering

6" he necessary data were obtained from the results of the

performance evaluation. hese data included the time elapsed in making one

stirrup with the specified dimension using the designed rectangular stirrup

bending machine and using the manual process.

7984 *.2 0aterial Seletion

&" he material selection was based on the material properties,

availability, cost and ease of fabrication.

&&" <ased on the designed rectangular stirrup bending machine,

electric motor must have a capacity of ) $p. Pulleys having a diameter of

5.08 cm and 12.7cm were used. o decrease the rotary motion of the

electric motor, a & speed reducer was used.

7124 *.2.1 Eletri 0otor

42



&-" he electric motor as shown in figure 7.).&a was purchased

in Cagayan de Fro City. 2s shown in figure 7.).&b, its power rating is ) $p and

rotates at &=) rpm. It is also a #ingle Phase Induction *otor.

614-

a

a

a

aa

a

aa

a

b615- Figure 4.2.1 a $lectric m!t!r and b M!t!r speci'icati!n

&"

71;4 *.2.2 P!lle# an" /elt

&6"

&5"

7294

7214

))"

)-"

624- Figure 4.2.2 ulle,s 5 in and 3 in and belt

7254

)" he Pulleys as shown in figure 7.).) has an outer diameter of +

inches and - inches with an inner diameter of & inch. he length of the belt is 7&

inches.

43



72;4

7264 *.2.$ Re"!er

)5" he reducer as shown in figure 7.).- is a surplus unit thus only few

specifications are available. It is a worm gear reducer and has a speed ratio of

&.

-"

7$14

7$24

7$$4

634- Figure 4.2.3 educer with a speed rati! !' 16

7$54

7$74 *.2.* S<ith Unit an" Cir!it /rea3er

7$;4

7$64

-5"

7"

7&"

642-643-

644-645-

646-

647-

648-

a

b64- Figure 4.2.4 a witch and b Circuit breaker

+"

44



+&" he #witch ?nit as shown in figure 7.).7a is an improvised foot

switch. It is a push button switch which is connected to an improvised foot

switch. In this mechanism, the machine will turn on when the switch is stepped

and automatically turn off when the foot is lifted.

+)"

75$4 *.$ -abriation an" In'tallation

+7" he designed rectangular stirrup bending machine was fabricated

and installed with the help of Remegio G:uya *ioH #alvador at $agkol, 8alencia

City as shown in figure 7.-.& and figure 7.-.). he fabrication of the machine

started on 4ebruary &, )&+ and was completed on 4ebruary )7, )&+.

655- Figure 4.3.1 Fabricati!n !' the machine656-

+="

+6"

+5"

"

&"

)"

-"

7"

665- Figure 4.3.2 nstallati!n !' the machine

45



7774 *.* Proe'' De'ri)tion

="

6"

5"

="

671- Figure 4.4.1 /elt checking

& Check if all the parts of the rectangular stirrup bending machine are

properly installed as shown in figure 7.7.&. 0<elt is not sagging. Bote

*ake sure the machine is not plugged on before checking and grounded

before using. ;ear personal protective equipment 0i.e. gloves, hardhat and

safety goggles1 during operation.

=)" ). 2d!ust the length and width guide to the desired length and

width of the stirrup as shown in figure 7.7.).

673-

674-

675-676-

677-

670-

46



67- Figure 4.4.2 )ength and width guide ad8usment

6"

6&"

6)"

6-"

604- Figure 4.4.3 t!pper and bender guide ad8usment

6+" -. 2d!ust the stopper and bender with respect to the size of the

rod to be bent as shown in figure 7.7.- 0&) mm1.

6" 7. est if the bender is properly ad!usted as shown in figure 7.7.7.

his is done by bending a rod and checking if the rod was bent to 90 3 )

If not, ad!ust the bender and check again. If the rod was bent to90

3

already, the machine is now ready for use.

47



6="

66"

65"6-

61-62-

63-

694- Figure 4.4.4 ⁰ 9ngle !' the r!d 695-696-697-

56"

55"

="

=&"

72- Figure 4.4.5 F!!t switch

p!siti!n

=-" +. Plug in the machine. Place the foot switch to its

position as shown in figure 7.7.+.

=7" . Place the rod at the initial position with the constant length of = cm

that serves as the lock for the stirrup as shown in figure 7.7.. <end first

the two ends of the rod and proceed to the ma!or four bendings.

48



=+"

="

=="

=6"

=5"

71-

Figure 4.4.6 !d%s initial p!siti!n

=&&"

=&)"

=&-"

=&7"

=&+"

716- Figure 4.4.7 /ending r!d

49



=&="

718- =. ;ait until the rod is perfectly bent to 903 and push it slightly

forward ready for the ne%t bending process as shown in figure 7.7.=.

=&5" 6. Repeat the procedure until all the 7 bends are completed as shown

in figure 7.7.6.

720-

;214

722- Figure 4.4.0 !d%s 'inal p!siti!n

;2$4 *.5 Performane Te't

;2*4 *.5.1 Ro" Pre)aration

50



725-

725-

725-

725-

725- Figure 4.5.1 !d preparati!n

726- 'ifferent lengths of rod were cut for the testing of the machine.

he lengths of the rod were as follow 6- cm, &6 cm, 57 cm and &) cm as

shown in figure 7.+.&. hese were used for the making of stirrups with the

dimensions of &).+ cm % )) cm, & cm % -& cm, ) cm % ) cm and )) cm % ))

cm, respectively.

;2;4 *.5.2 Ro" /en"ing

=)6" he stirrup with the dimension of &).+ cm % )) cm, & cm % -&

cm, ) cm % ) cm and )) cm by )) cm were made using the rectangular stirrup

bending machine. he process description was followed strictly in order to avoid

accidents. he performance testing of the designed machine was done in the

/ngineering laboratory, *usuan, <ukidnon last *arch -, )&+.

=)5"

730-

;$14 CHAPTER 5: RESUTS AND DISCUSSION

51



;$24

;$$4 5.1 E&al!ation an" Te't

=-7" he performance of the rectangular stirrup bending machine was

tested in terms of productivity and was compared to the conventional way of

bending rods with the specified dimensions. he data for the traditional manual

bending were gathered by taking the time elapsed in completing one stirrup

without the knowledge of the operator but with the permission of the supervisor.

his was done by making stirrups with four different dimensions specifically,

&).+ cm % )) cm, & cm % -& cm, ) cm % ) cm and )) cm % )) cm for three

trials and the time elapsed was then recorded as shown in the following table.

=-+" he comparative time elapsed in completing one &).+ cm % )) cm

stirrup is shown in able +.&.&. he manual bending procedure achieved an

average time of .+ seconds out of three trials while the rectangular stirrup

bending machine attained )+.-& seconds. It can be observed in 4igure +.&.& that

the performance of the fabricated machine is faster by 7&.-7 seconds compared to

the manual bending process.

=-" able +.&.& /valuation Result for &).+ cm % )) cm

;$;4;$64 Stirr!)

Dimen'ion

739- >12. 5 m 22 m?

;*94

;*14 Ela)'e" Time in Com)leting One

Stirr!)

;*24 in 'eon"'743-

;*54 0an!al ;*74 Retang!lar

Stirr!) /en"ing

0ahine

=7=" RI2A & =76" -. =75" ).6+

=+" RI2A ) =+&" +.& =+)" )+.

=+-" RI2A - =+7" =&.66 =++" )-.75

52



=+" 28/R2@/

I*/

=+=" .+ =+6" )+.-&

=+5"

76-

0

10

20

30

40

50

60

70

80

63.06 65.0171.88

66.65

26.85 25.6 23.49 25.31

12.5 x 22 cm Stirrup

Manual

Rectangular Stirrup

Bending Machine i!e" #ec$nd#

Figure 5.1.1 9ssessment '!r the time !' c!mpleti!n !' the 12.5 cm : 22 cm

stirrup in sec!nds# s# using the bending machine c!mpared t! manual

bending 761-

=)" 2s shown in table +.&.), the average time in completing a & cm %

-& cm stirrup is =.+ seconds for the manual operation and -.&) for the

rectangular stirrup bending machine. ;ith these data, it is very obvious that the

fabricated machine is faster by -.5- seconds than the manual performace. o

help visualize the result, figure +.&.) is presented below.

=-"

=7" able +.&.) /valuation Result for & cm % -& cm

;754;774 Stirr!)

Dimen'ion

;764

;784 Ela)'e" Time in Com)leting One

Stirr!)

;;94 in 'eon"'

53



767- >17 m

$1 m?

771-

;;$4 0an!al ;;*4 Retang!lar

Stirr!) /en"ing

0ahine

==+" RI2A & ==" &.-6 ===" )=.5&

==6" RI2A ) ==5" =7.) =6" )5.5)

=6&" RI2A - =6)" +.& =6-" -).+)

=67" D

28/R2@/ I*/

=6+" =.+ =6" -.&)

707-

0

10

20

30

40

50

60

70

80

61.38

74.62

65.16 67.05

27.91 29.92 32.52 30.12

16 x 31 cm Stirrup

Manual

Rectangular Stirrup


Figure 5.1.2 9ssessment '!r the time !' c!mpleti!n !' the 16 cm : 31 cm stirrup in sec!nds# s# using the bending machine c!mpared t! manual

bending

=66"

=65" In able +.&.- shows the results gathered in making the )) cm % ))

cm stirrup. ;ith this dimension, the rectangular stirrup bending machine was

able to record an average time of -+.5 seconds while the recorded average time

in the manual operation was 6-.-& seconds. he fabricated machine performed an

advantageous time of -6.5- seconds compared to the manual bending process.

4igure +.&.- will help in the assesment of the results.

54



=5" able +.&.- /valuation Result for )) cm % )) cm

;814;824 Stirr!)

Dimen'ion

793- >22 m

22 m?

;8*4

;854 Ela)'e" Time in Com)leting One

Stirr!)

;874 in 'eon"'

797-;884 0an!al 6994 Retang!lar

Stirr!) /en"ing

0ahine

6&" RI2A & 6)" 6.&- 6-" +7.7=

67" RI2A ) 6+" 66.++ 6" 7-.+6

6=" RI2A - 66" 6&.)+ 65" -+.5

6&" 28/R2@/

I*/

6&&" 6-.-& 6&)" 77.-6

013-

0

10

20

30

40

50

60

70

80

90

100

80.1388.55

81.25 83.31

54.47

43.58

35.09

44.38

22 x 22 cm Stirrup

Manual

Rectangular Stirrup


Figure 5.1.3 9ssessment '!r the time !' c!mpleti!n !' the 22 cm : 22 cm stirrup in sec!nds# s# using the bending machine c!mpared t! manual

bending

014-

6&+" ;ith the ) cm by ) cm stirrup , the rectangular stirrup bending

machine completed the operation with an average time of -&.=& seconds while

=7.7= seconds was the average time of completion in the manual bending process

as shown in table +.&.7. 2s shown in figure +.&.7, the rectangular stirrup bending

machine is 7).= seconds faster compared to the manual bending operation.

55



6&"

6&=" able +.&.7 /valuation Result for ) cm % ) cm

6164

6184 Stirr!)Dimen'ion

820- >29 m

29 m?

6214

6224 Ela)'e" Time in Com)leting One Stirr!)

62$4 in 'eon"'824-

6274 0an!

al

62;4 Retang!lar Stirr!)

/en"ing 0ahine

6)6" RI2A

&

6)5" =.67 6-" )5.-7

6-&" RI2A

)

6-)" 6.+ 6--" -&.-+

6-7" RI2A

-

6-+" .) 6-" -7.7+

6-=" 28/R2

@/ I*/

6-6" =7.7= 6-5" -&.=&

04-

041-

042-

0

10

20

30

40

50

60

7080

90

100

70.84

86.56

66.0274.47

29.34 31.35 34.45 31.71

20 x 20 cm Stirrup

Manual

Rectangular Stirrup


Figure 5.1.4 9ssessment '!r the time !' c!mpleti!n !' the 2 cm : 2 cm

stirrup in sec!nds# s# using the bending machine c!mpared t! manual

bending 043-

044-

045-

56



046-

047-

040-

04-

05-

051-

052-

053-

054-

055-

056-

65;4 CHAPTER 7: SU00AR=@ CONCUSIONS AND

RECO00ENDATIONS

65646584 SU00AR=

6794

6&" he study was conducted to design, fabricate and test the

performance of the rectangular stirrup bending machine in terms of productivity.

6)" he rectangular stirrup bending machine is composed of an electric

motor, improvised foot switch, pulleys and belt, reducer, measuring device and

steel plate in various dimensions for the crank"rocker mechanism, oscillating

table, stopper, and frame for the whole support of the machine.

6-" he machine is operated with the help of an electrical power, when

the foot switch is stepped on, powering the motor, rotating the pulley and then the

57



reducer which oscillates the table with the help of the crank"rocker mechanism

and bends the rod placed on top of the support.

67" <efore operating the rectangular stirrup bending machine, its

conditions were carefully checked and necessary ad!ustments were made. he

machine was tested in the /ngineering #ervices building with the aid of >uanito

G:uya BitoyH Cabahug. he necessary data were then gathered and recorded.

6+" he average time performance for the rectangular stirrup bending

machine with each stirrup dimension is relatively faster than the manual bending

operation as shown in previous chapter, hence it increases productivity and

requires less human power.

6774 CONCUSION

67;466" he analysis and evaluation of the gathered data is an important

parameter in attaining the ob!ectives of the study. he rectangular stirrup bending

machine is of no e%ception. he machine had underwent and passed a series of

tests on four different stirrup dimensions 0&).+ cm % )) cm, & cm % -& cm, ) cm

% ) cm and )) cm % )) cm1 to evaluate its performance that was then compared

to the manual bending operation. Comparing the manual bending operation to the

rectangular stirrup bending machine, the rectangular stirrup bending machine is

faster by 7&.-7 seconds for the &).+ cm % )) cm, -.5- seconds for the & cm % -&

cm, -6.5- seconds for the )) cm % )) cm, and 7).= seconds for the ) cm % )

cm stirrup dimensions compared to the manual operation. he rectangular stirrup

bending machine when used could increase the productivity of the stirrup

58



production in construction sites, which requires less human energy than the

manual bending operation. he rectangular stirrup bending machine attained its

purpose of innovation since it could improve the productivity, and provides

comfort to the steel men.

6784

6;94

6;14

6;246;$4

6;*4

6;54

6;74

6;;4 RECO00ENDATIONS

6;646=5" In the operation of the rectangular stirrup bending machine, it is

strongly recommended that the operator must be knowledgeable and have enough

e%perienced in order to bring out the best of the machine. he speed may be

altered to a faster or slower pace by changing the size of the pulley which is

connected to the reducer. ;hen testing the machine, the setting of the machine

must be checked to make sure it conforms to the 5 degree angle bend output.

2d!ustments to the stopper and bender must be done before doing an operation.

4or safety purposes, changing and covering of the footswitch is highly

recommended to avoid unnecessary stepping thus powering the machine without

the will of the operator.

66" 4or further improvement, the accessories of the rectangular stirrup

bending machine like the measuring tool can be improved by changing its

material and adding a calibration fi%ed on the machine in order to ease the

ad!ustments with the said device. 2ddition of an improved locking system for the

bender to ease the ad!ustment is recommended. *aking the table wider for large

59



dimensions stirrup is also a good improvement. It can also be considered to add a

platform on the right part of the machine which levels the mounting table to place

the rods ready for bending for ease and comfort of the operator and an automatic

cutter which operates with the same motor as the machine for the rods is

recommended to solve the problem in manual cutting and could increase

production. 2 cart for the machine is also recommended for easy transport from

place to place. 2ddition of sensors is highly recommended to automatically stop

the machine and improve its safety features to eliminate possible accidents.

66&" Referene'

662466-" <udynasNBisbett. 0)1. #higleyEs *echanical /ngineering 'esign, 6th

/dition, *c@rawN$ill Companies, Inc. Bew Kork.667"

66+" 'oughtie 8.A., >ames ;.$. 0&5+71. /lements of *echanism, >ohn ;iley

and #ons Inc.66" Bew >ersey.

66="

666" $anoof *., 8ishwanth R., #ureshkumar P., #aravanan B. 0)&71. 'esign and4abrication of $ydraulic Rod <ending *achine, I>IR#/, 8olume -, #pecialIssue ). India.

665"

65" :hurmi R.#., @upta >.:. 0)+1. 2 e%t <ook of *achine 'esign, /urasiaPublishing $ouse 0Pvt.1 Atd, India.

65&"

65)" *erritt, 4rederic #., *. :ent Aoftin and >onathan . Ricketts. 0&55+1. tandard ;andb!!k '!r Ci(il $ngineers# F!urth $diti!n, *c@raw"$ill <ook Company.

Bew Kork.

65-"

657" Bilson 2. $. 0&55=1. 'esign of Concrete #tructures, *c@raw"$ill International/ditions, &)th /dition. Bew Kork.

65+"

65" Padole P. *., 8analkar 2.8. 0)&1. Fptimal 'esign of *echanism for #tirrup*aking *achine" 2 Computer 2pproach. India.

65="

656" Pytel, 2. and #inger, 4. 0&56=1. #trength of *aterials, $arperCollins PublishersInc., 7th /dition. Bew Kork.

60



655"

5" Robert A. *ott. 0&5551. *achine /lements in *echanical 'esign, -rd

/dition, Prentice" $all Inc., Inc. Bew >ersey.5&"

5)" Robert A. Borton. 0)&1. 'esign of *achinery 2n Introduction to the

#ynthesis and 2nalysis of *echanism and *achines, )nd

edition, *c@rawhill. Bew Kork.

5-"

57" #heth #., amboli :., 8ekariya >., 8irani *. 0)&-1. 'esign and'evelopment of 2utomatic #tirrup <ending *echanism, IB2CF**.

India.

5+"

5" 8analkar 2.8. , et. al. 0&5551. 'esign 'evelopment and 4abrication of #tirrup *aking *achine, Proceeding, 5th Bational Conference on

*achines and *echanisms, B2CF** &555, I. I. . , Powai, *umbai, India.

5="

56"

55"

5&" 2ppendi% 2

8114 Definition of term'

5&)" /elt Dri&e O a mechanism in which power is transmitted from engine bymeans of a moving belt.

5&-"

5&7" /en"ing Stre'' the normal stress that is induced at a point in a body

sub!ected to loads that cause it to bend.

5&+"

5&" Defletion the degree to which a structural element is displaced under a load. It may refer to an angle or a distance.

81;4

5&6" -o!r bar lin3age a four bar linkage or simply a 7 bar or four bar is the

simplest movable linkage. It consists of 7 rigid bodies 0called bars or links1, eachattached to two others by single !oints or pivots to form a closed loop.

5&5"

61

http://en.wikipedia.org/wiki/Force


http://en.academic.ru/dic.nsf/enwiki/708934/Four

http://en.academic.ru/dic.nsf/enwiki/708934/Four




5)" 0oment a combination of a physical quantity and a distance. *oments

are usually defined with respect to a fi%ed reference point or a%is( they deal with

physical quantities as measured at some distance from that reference point or a%is.

5)&"

5))" P!lle# is a wheel on an a%le or shaft that is designed to supportmovement and change of direction of a cable or belt along its circumference.

82$4

5)7" Re"!er a train of gears placed between a motor and machinery which it

will drive, to reduce the speed with which power is transmitted.

5)+"

5)" Ultimate Strength the ma%imum stress that a material can withstand

while being stretched or pulled before failing or breaking.

5)="

5)6" =iel" Strength the stress at which a material begins to plasticallydeform.

5)5"

5-" 2ppendi% <

8$14 A))arat!' an" EB!i)ment U'e"

5-)" A"%!'table <renh an ad!ustable tool for gripping he%agonal nuts, with

an ad!ustable crew in the head of the implantation.

5--"

5-7" Allen 3e# an A"shape tool consisting of a rod having a he%agonal cross

section, used to turn a screw with a he%agonal recess in the head.

5-+"

8$74 Chal3 'tone used to write on metal surface.

8$;4

5-6" Ha3'a< a fine"tooth hand saw with a blade held under tension in a

frame, used for cutting materials such as metal or plastic.

5-5"

57" 'B!are instrument for drawing or testing right angles.

62



8*14

57)" 0etal ta)e mea'!re a tape measure that is made of steel and is markedoff in a linear scale. he scale could be in inches andDor centimeters. he steel

tape is used for taking measurements and it is also referred to as a tapeline.

57-"

577" San"er a power tool used to smooth surfaces by abrasion withsandpaper.

57+"

57" T <renh is a tool used to provide grip and mechanical advantage in

applying torque to turn ob!ectsusually rotary fasteners, such as nuts and bolts

or keep them from turning.

57="

576" +i'e gri) a small instrument with two handles and two grasping !aws,

usually long and roughened, working on a pivot( used for holding small b!ects and

cutting, bending, and shaping wire.

575"

5+" ,el"ing mahine equipment used to perform the welding operation.

5+&" 2ppendi% C

8524 EECTRIC CIRCUIT

953-

63

http://en.wikipedia.org/wiki/Tool

http://en.wikipedia.org/wiki/Mechanical_advantage

http://en.wikipedia.org/wiki/Torque

http://en.wikipedia.org/wiki/Fastener

http://en.wikipedia.org/wiki/Nut_(hardware)


http://en.wikipedia.org/wiki/Screw

http://en.wikipedia.org/wiki/Tool

http://en.wikipedia.org/wiki/Mechanical_advantage

http://en.wikipedia.org/wiki/Torque

http://en.wikipedia.org/wiki/Fastener


http://en.wikipedia.org/wiki/Screw



954-

955-

5+" Aegend

5+=" * J *otor

5+6" C< J Circuit <reaker

5+5"

5" 2ppendi% '

8714 0aterial' U'e" in Performane Te't

5)"

64



5-"

57"

5+"

66-

67-

Figure 6.1 Materials used in the per'!rmance test

56"

55"

5="

5=&"

5=)" 2ppendi% /

8;$4 De'ign of the Retang!lar Stirr!) /en"ing 0ahine

65



5=7"

5=+"

5="

5=="

5=6"

7-

0- a b

56&"

56)"

56-"

567"

05-

06-

07- c

566" Figure 6.2 a Fr!nt (iew< b /ack (iew< c =rimetric (iew !' the ectangular tirrup /ending Machine

66



565"

55"

55&"

55)"

55-"

557"

55+"

6- a

7-

556"

555"

&"

19914&)"

&-"

&7"

15- b

16- Figure 6.3 a =!p (iew !' the ectangular tirrup /ending Machine and

b ectangular tirrup /ending Machine&="

&6" 2PP/B'IQ 4

19984 Sam)le Pro"!t' of Retang!lar Stirr!) /en"ing 0ahine

19194

111-

67



112- a

113-

1014-

115- b

1016- Figure 6.4 a 12.5 cm : 22 cm tirrup and b 16 cm : 31 cm tirrup

117- a

68



19164

19184

19294

19214

19224

192$4

192*4

19254

19274

192;4

19264

19284

19$94

19$14

132- b

1033- Figure 6.5 a 2 cm : 2 cm tirrup and b 22 cm : 22 cm tirrup

&-7" 2PP/B'IQ @

19$54 /I O- 0ATERIAS AND -A/RICATION COST

19$74 19$84 19*24 19**4

69



19$;4

!anti

t#

19$64 19*94 0aterial

19*14

Prie

Un

it

19*$4

Total

Pri

e

19*54

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Ph

p

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Php

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&+)"

&+

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&+7"&

&++" C. I Pulley -3 % )< &+"))

Ph p

&+=")) Php

&+6"&

&+5" Push <utton #witch &"

-)

Ph p

&&"-) Php

&)"7 &-" Cord &7 0/lectrical ;ire1

&7"+5 Php

&+")- Php

&"& &=" Plug $p

&6"-+ Php

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&="

&

&=&" Circuit <reaker &=)"

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p

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) &=+" +D6 % & &D) <olt

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) &=5" -D6 % & &D) <olt

&6"

& Php

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&66"

&65"))7 Php

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70



&&)"

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