Belts, Chain, Gears test teacher Flashcards
what length of belt is required if the centre to centre distance is 51” and the small pulley is 10” and big pulley is 30 “ formula –( (D+d)/2 ) x pi + 2xc pi=3.1416 c=centre to centre distance
19’ 6”
17’ 8”
20’ 4”
13’ 9”
13’ 9”
a variable speed drive changes belt position from the top of the driver sheave to the bottom. this results in a
speed increase
speed decrease
no speed change
reverse of direction
speed decrease
.a v-belt code marked 5V 250 on the outside means
5/8” wide by 25” long
5/8” wide by 250” long
3/8” wide by 25 “ long
3/8” wide by 250” long
Option 5
5/8” wide by 25” long
the term used to describe the tension needed on a belt to transmit power without slippage is
effective tension
installed tension
equal tension
free tension
effective tension
v-belt drives achieve a tighter belt grip than flat belts due to the
area of contact
wedging action
efficiency of friction
arc of contact
weddgng action
positive drive belts (similar to chain drives) and must be used with
low loads and speeds
pulleys of the same pitch
small pulleys
all the above
pulls of the same pitch
polly v-belts are constructed by adding a cover backing to the top of 2 or more conventional belts
true
False
false
the standard crowm built into the a flat pulley is
1/8”/ft
1/16”/ft
1/3 of the belt width
1/96
both the first and 4th answers are correct
both the first and 4th answers are correct
the width of a pulley for a flat belt of a 7” width would be
8”
9”
10”
7”
9”
chirping is caused by
dust
over-tightened belts
idler pulleys
cocky students
dust
a sheave that has both A and B section grooves on it is known as a ______________
variable sheave
adjustable sheave
combination sheave
none of the above
combination sheave
belt storage for synthetic belts should be in a
cool and dry place
cool and humid place
damp and dark place
it does not matter
cool and humid place
variable speed sheaves are adjusted
slowly while stopped
while running
at rest
stopped and locked out
while running
linked v-belts are
used in an emergancy
used on sheaves that are mounted inside bearings
available in the smae power rating as standard belts by some manufacturers
all the above
all the above
if an idler is needed to increase the arc of contact on the drive pulley, you need to put the idler
inside near the driver
inside near the driven
outside near the driver
outside near the driven
outside near the driver
if the v-belt inside diameter is cracked, the most likely cause/s is
misalignment
the pulley diameter is to small
burning caused by excessive slip
both the 2nd and 3rd answers are correct
both the 2nd and 3rd answers are correct
the pitch line of a v-belt is at the
insulation area
tensile member
cushion layer
cover
tensile member
if an idler is added to the inside of a v-belt to tension it, the idler would
decrease the arc of contact
be a grooved or flat pulley
be put on the slack side at a point that produces equal arcs of contact on the sheaves
all the above
all the above
what could happen if you use never seize on the tapered surfaces of a tapered bushing and a cast sheave being mounted on a shaft
seize on the shaft
cause less friction on the shaft
break the pulley
nothing, this is what you are suppost to do
break the pully
why should you not depend on feel when checking the tension of the belt
everyone has a different feel for tension
tensile members of different strengths require different tensions
different belt manufactureres have differne standards
all the above
all the above
the amount of power that a v-belt can transmit depends on the arc of contact, tension applied and the coefficient of friction between the belt and pulley
true
false
true
slip is when creep of the belt increases to extend all the way around the pulley because of an increase in load
true
false
true
cogged raw edged belts
are designated by an x at the end
have good flexibility
have a high coefficient of friction
all the above
all th above
banded belts help stop belt turn-over
true
false
true
open-ended v-belts have a carrying capacity of__________ of that of an endless v-belt
1/4
1/3
3/4
there is no marked difference
1/3
if a new v-belt runs down in the groove, it is time to
change the hub
change the sheave
both the first and 2nd answers are correct
none of the above
change the sheave
if a v-belt has a cut bottom and side-wall, this indicates that the
belt was pried onto the sheave during installation
belt was oil-soaked
belt had a back-side idler
sheave was to large
belt was pried onto the sheave during installation
if a v-belt is found to have swollen in size, this is an indication of
belt exposed to water
belt exposed to oil
belt running in hot conditions
All the above
belt exposed to oil
when using a straight edge to check for sheave alignment, you should make sure the maximum misalignment does not exceed
1/16” per 6” of belt span
1/16” per foot of belt span
1/4” per 6” of belt span
1/4” per foot of belt span
1/16” per foot of belt span
if you find a banded belt having cuts thru the backing and the running in the bottom of the seave grooves, you should
add more backing
loosen off the tension
replace the sheaves and belt
check for proper belt material
replace the sheaves and belt
you are checking for _________ when you have a dial indicator reading off of one of the sheave groove faces
sheave rim runout
sheave damage
sheave runout
proper alignment of the sheave to the other sheave
sheave run out
when using a deflection gauge to check for proper telt tension, you need to set the force applied o-ring to 0 and the other o-ring to the proper deflection distance for that belt
true
false
true
quarter turn belts
a maximum speed ratio of 2.5 to 1
centre distance of 5.5 times the sum of the large sheave diameter plus its face width
its centre line of the horizontal shaft abov the centre line of the vertical shaft
all the above
all the above
before checking the belt for proper tension, you should always rotate the belt and sheaves a few turns
true
false
true
synchronous belts are timing belts
true
False
true
synchronous belts need _______ degrees of arc contact on the sprocket and _____ teeth engaged
120, 6
60, 8
60, 6
100, 8
60,6
if a belt is snaking from one sheave to the other while running indicates
sheave runout
sheave misalignment
shaft runout
all the above
all the above
standard belts are designed to run at a maximum of ____degrees Celsius
50
60
80
100
60
synchronous belts are about 98% efficient and need less tension then the standard v-belts
true
false
true
if you are using plastic sheaves, you are in a/an
highly abrasive environment
light duty installation
a high temperature environment
all the above
light duty installation
chain sprockets are describe by letters A,B,C,D. these refer to the hub_________
bore
class
size
diameter
class
the minimum amount a roller chain can be shortened is
1 link
1 pitch
1/2 pitch
2 links
1 pitch
a modified leaf chain that forms a tooth pattern when assembled is a
wrench chain
silent chain
vise chain
oil field chain
silent chain
a type D sprocket is of a___________ design
steel plate
split hub
hub 1 side
hub both sides
split hub
a chain designated #120-2 has a pitch of
3/4”
1 1/4”
1”
1 1/2”
1,1/2
the recommended lubrication system for drives of moderate speed and load is
manual
bath
pump with a stream flow
drip
bath
when ever possible, install horizontal chain so that it runs with the
top strand tight
bottom strand tight
top and bottom strand loose
idler loose
top strand tight
idler sprockets should
always be placed inisde the chain
have at least 3 teeth engaged
have at least 5 teeth engaged
increase the tension on the slack side of the chain
increase the tension on the slack side of the chain
a type B hub should be mounted with
the hub next to the bearing
hubless face next to the bearing
a clearnace of 0.008” from the end of the shaft
none of the above
hubless face next to the bearing
what is the installed sag in the bottom strand for a 125” centre to centre distance and running at a high speed sag(in inches)= c to c distance x % of sag allowed
1” to 2”
1.5” to 2”
2.5” to 3.75”
4” to 5.75”
2.5” to 3.75”
a # 2080 chain is a
double pitch chain with a 2” pitch
double strand chain with a 2” pitch
a double strand chain with a 1” pitch
a double pitch chain with a 1” pitch
double pitch chain with a 2” pitch
a chain drive with misalgnment would have noticable wear on the chain
side plates (inside)
pins
rollers
side plates (outside)
side plates (inside)
a drive has a sprocket with 24 teeth and a driven sprocket with 32 teeth. the c to c distance is 33”. what is the approximate length of the chain needed for the drive, if the chain size is 100 roller chain
99”
101”
103”
89”
101
a double pitch chain with a regular pitch sprocket (single pitch), how would you get even wear on all teeth
use 2 even numbered tooth sprockets
use 1 even and 1 odd numbered tooth sprockets
use 2 odd numbered tooth sprockets
all of the above
use 2 odd numbered tooth sprockets
sintered bushing chain has what follwoing characteristics
has 0-rings
10 % stronger than standard chain
lasts 5 times longer than standard chain
lasts 5 times longer than standard chain
rollerless chain has a designation of ___ when chain is below a 1/2” pitch
1
5
0
25
5
when selecting a chain, you should find which of the following
horse power
driver and driven shaft speeds
operating environment
all the above
all the above
when ordering a sprocket, you need to know
the class of hub and size of chain
the pitch and number of teeth
if the teeth need to be hardened
all the above
all the above
the weakest link in roller chain is the
2 pitch offset link
1 pitch offset link
the press fit master link
all are equally weak
1 pitch offset link
multiple strand chain is used when ________ for a single chain
the speed is to high
the load is to great
the load is minimal
both the 1st and 2nd answers are correct
both the 1st and 2nd answers are correct
0-ring chain keeps out contaminants, sealed for life and lasts about 10 times that of standard chain
true
false
true
silent chain is used in high horse power applications and where there is limited space for the drive
true
false
true
the split on the master link spring clip should face the direction of travel
true
false
false
alignment of chain drive shafts and sprockets must be corrected in the horizontal and vertical planes which includes offset and angular misalignment
true
false
true
when lubricating roller chain, you must oil the chain with high grade petroleum oil with proper additives and add the oil between the side plates on the inside of the chain
true
false
false
forced lubrication is used on heavily loaded drives operating above the speed limits of the bath lubrication system
true
false
true
if the teeth on a sprocket are hooked or thinned down (face and / or depth) and / or the chain has been exposed to excessive loading, you must
change the sprocket
change the chain
check for misalignment
all the above
all the above
a chain drive should have the chain have 120 degrees of contact with the small sprocket or a speed ratio of 3 to 1
true
False
true
.a double single sprocket is designed to be used with a 2 strand chain
true
false
fasle
keyless bushings are used in places where good balance is needed of the drive sprocket and also where there is no keyway
true
false
true
when installing a cylindrical bore sprocket hub, you need to keep the dial readings to _______ for runout
0.010”
0.005”
0.002” or less
0.000”
0.002” or less
broken roller chains or sprockets are a sign of shock or overload
true
false
true
a stiff chain is a sign of
faulty lubrication
rust or corrosion
misalignment
all the above
all the above
ideally, join the roller chain on the sprocket teeth
true
False
true
if you pull on the chain on the back side of the sprocket and it pulls away from the sprocket, this is a sign of
worn side plates
worn locking devices
worn pins and bushings
wrong pitch
worn pins and bushings
align parallel shafts in a chain drive with a feeler bar
true
false
true
silent chain needs to be held on the sprockets with guide plates or a flanged sprocket
true
false
true
on roller chain, the roller diameter is approximately 5/16 of the pitch of the chain
true
false
fALSE
speed ratio can be high speed shaft rpm/low speed shaft rpm or # of teeth on driven sprocket/#of teeth on the drive sprocket. ( / = divide )
true
false
true
a gear system that is exposed to over hung loads are
gears with bearings on both sides
gears with bearings on only one side
gears on parallel shafts
double helical gears
gears with bearings on only one side
a floating gear or shaft is
one that floats axially to find its centre
one that floats radially to find its centre
one that has prelaod in the bearings that support it
either a worm or wheel gear
one that floats axially to find its centre
bevel gears are
used on intersecting shafts
cut out of blanks shaped like cones
used at 90 degree angles only
both the first and 2nd answers are correct
used on intersecting shafts
cut out of blanks shaped like cones
hypoid gears
are used in shafts crossing over
can be straddle mounted
need extreme pressure lubes
all the above
all the above
when setting up a worm and wheel reducer for contact between the worm amd wheel, it should be
acrossl the face or the entire tooth
slightly off centre toward the leaving side of the worm whee;
contacting the top of the teeth only
contacting the bottom of the teeth only
slightly off centre toward the leaving side of the worm whee;
worms and wheels that are double throated
have more contact because of the prelaod in the bearings
have adjustments for backlash
have more engagement with each other (more depth)
have less power transfer in the reducer than non-throated
have more engagement with each other (more depth)
.planetary gears have the following 4 main parts
sun, carrier, ring and bearings
sun, carrier, ring and planet gears
sun, carrier, moon , planet gears
sun, carrier, ring and bushings
sun, carrier, ring and planet gears
with planetary gear systems, which cannot be held
the ring
the sun
the carrier
the planets
the planets
if you see pitting on the gears of a drive unit, this would be caused by
wrong lubricant
heavy loads and low speeds
contaminated lubes
all the above
all of the above
in a gear reducer, lubrication is diverted to all areas needing lubrication by
scrappers
dams
baffles
all the above
all the above
when using lead wire to check backlash, you should measure the wire on
one side of the tooth and double it
both sides of the tooth at the outside diameter
both sides of the tooth at the pitch line
the back side and the top
both sides of the tooth at the pitch line
all gear tooth profiles are of the involute form
true
false
false
SM cycloid reducers must have
shims put between the housing haves to set the backlash
extreme pressure lubes
the sheave mounted as close to the bearing as possible
blueing to check gear contact
the sheave mounted as close to the bearing as possible
when installing an idler between the 2 gears, you know that
the final gear will turn in the same direction as the first gear
the final gear will turn in the opposite direction as the first gear
the idler will not change speed ratio of the gear system
both the 1st and 3rd answers are correct
both the 1st and 3rd answers are correct
backstops on inclined conveyors are used to
set up the sheave alignment
stop reverse rotation of the conveyor
protect the drive from damage
all the above
stop reverse rotation of the conveyor
when adjusting for correct preload of the worm and wheel tapered roller bearings
add shims between the bearing caps and reduction unit housing to increase the preload
take out shims between the bearing caps and reduction unit housing to decrease the prelaod
take out shims between the bearing caps and reduction unit housing to increase the preload
add shims between the bearing caps and reduction unit housing to take out axial float
take out shims between the bearing caps and reduction unit housing to increase the preload
the addendum is a greater length than the dedendum
true
false
false
the shaft centre distance between a pair of meshing gears is the sum of their individual pitch circle diameters
true
False
false
when the revolutions of the driven gear increase, the torque of that gear increases
true
False
false
correct meshed gears always have pitch circles that coincide at the pitch point
true
False
true
when shaft mounted drives provide only part of the total reduction needed, the remainder will be furnished by a
geared coupling
mitre gear box
second reducer
set of v-belts and sheaves
set of v-belts and sheaves
what is the primary type of lubrication system used in worm and wheel reducers
forced feed
circulating pump
splash
dry sump
splash
rack and pinion gears have one gear with a striaght pitch line while the other has a circular pitch line
true
false
true
2 meshing single helical gears of the same hand will only connect shafts that are parallel
true
false
false
which of the following shaft conditions will prevent a shaft mounted reducer from being properly installed
out of round
misaligned
bent
all the above
all the above
bevel gears develop both axial and radial thrust loads and need bearings that can accomadate both types of loads
true
False
true
the space between the gear sets mating teeth at the root is called the
backlash
working depth
clearance
pressure angle
clearance
double helical gears do not have what feature that herringbone gear teeth have
slight interference between gears
a helix angle close to 20 degrees
a formed point at the tooth profile centre
less clearance in the teeth
a formed point at the tooth profile centre
which of the following gear type reduces the thrust
simple helical
miter
double helical
spiral bevel
double helical
the outside diameter of a gear is equal to
the root circle diameter plus 2 dedendums
the pitch circle diameter plus 2 dedendums
th pitch circle diameter plus 2 addendums
the root circle diameter plus 2 working depths
th pitch circle diameter plus 2 addendums
to ensure correct mesh pattern between a worm and wheel reduction unit, you must
1-assemble and install worm shaft and bearings with proper shim pack to get correct preload
2- add light coat of prussion blue to worm
3-mount worm wheel and bearings, use proper shim pack for bearing clearances
4-rotate worm in proper direction with applying resistance to the worm wheel
5-check contact pattern and adjust with shims moved from one side to the other to get a contact pattern slightly toward the leaving side of the worm wheel
true
false
true
an 8 DP refers to a gear that has
8 teeth per inch of the gears outside diameter
8 teeth per inch of the gears root circle diameter
8 teeth per inch of the pitch circle circumference
8 teeth per inch of the gears pitch circle diameter
8 teeth per inch of the gears pitch circle diameter
backlash can be checked within a helical gearbox by using the lead wire procedure which is
place the lead wire into the gears and bolt down cover to squeeze the lead wire
run lead wire between the mating teeth, then recover the wire and measure the thickness at the deformed regions at the pitch line
place the lead wire at the root of one gear and turn gears until a mating tooth deforms the wire than measure wire at deformed section
stretch the lead wire till it can fit between mating teeth. than measure wire thickness
run lead wire between the mating teeth, then recover the wire and measure the thickness at the deformed regions at the pitch line
use a stainless steel chain for wet and corrosive conditions
true
false
true
adding a jackshaft to a drive system will help
increase the arc of contact on the small sprocket
reduce the overall ratio of the original drive by dividing it up
decrease chain and sprocket wear
all the above
all the above
a slip fit master link decreases the strength of the chain by ____%
10
20
30
40
30
