Belt, Chain, Gear Test Flashcards
What length of belt is required if the c to c distance is 51”, small pulley is 10” big pulley is 30”?
Formula:
((D+d) /2) x pi(3.1416) + 2 x c
13’9”
A variable speed drive changes belt position from the top of the driver sheave to the bottom. This results in a speed_________
Decrease
A v-belt code marked 5v 250 means?
5/8” wide 25” long
The term used to describe the tension needed on a belt to transmit power without slippage is?
Effective tension
V belt drives achieve a tighter belt grip than flat belts do to the?
Wedging action
Positive drive belts (similar to chain drives) must be used with?
Pulleys of the same pitch
Polly V belts are constructed by adding a cover backing to the top of two or more standard belts with a backing.
True or false
False : banded belts are built by adding backing to two or more standard belts
The standard crown put into a flat pulley is?
1/8” per foot
Or
1/96
Same thing
The width of a pulley for a flat belt of a 7” width would be _______.
1 inch extra on each side.
=
9”
A sheave that has both A and B section grooves on it is known as a ________
Combination sheave
Variable speed sheaves are adjusted while the Machine is ________?
Running
Belt storage for synthetic belts should be in a _________ and _______ place?
Cool and humid
If the V belt inside diameter is cracked, the most likely cause is?
Pulley diameter to small
Or
Burning caused by slippage
If an idler is needed to increase the arc contact on the drive pulley, you need to put the idler where?
Outside near the driver
Linked v belts are used when?
Emergency
On sheaves mounted inside bearings
Depending on manufacture can be same power rating
Chirping in belts is caused by?
Dust
The pitch line of a v belt is at the?
Pitch line
If an idler is placed on the inside of a v belt to tension it, the idler would:
Decrease the arc of contact
Be a grooved or a flat pulley
Be put on the slack side at a point that produces equal arc of contact on the sheaves
What could happen when you use anti seize on the tapered bushing and a CAST sheave when mounting on a shaft?
Break the pulley
Why should you NOT depend on feel when tensioning a belt?
Everyone has a different feel for tension
Tensile members have a different strengths and require different tensions
Different belt manufactures have different standards
The amount of power that a v belt can transmit depends on the arc of contact, tension applied and coefficient of friction.
True or 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 or false
True
Cogged raw edge belts:
Designated by an x at the end
Have good flexibility
Have high coefficient of friction
Banded belts help stop belt turn over.
True or false
True
Open ended v belts have a carrying capacity of _______ that of an endless v belt.
1/3 the capacity
If a new v belt runs down the groove of the sheave it is time to?
Replace the sheave
If a v belt has a cut bottom and side wall this indicates the belt was __________?
Pried onto the sheave
If a v belt is found to be swollen in size, this is an indication of the belt exposed to _________?
Oil
If you find a banded belt having cuts thru the backing and running in the bottom of the sheave grooves, you should?
Replace sheaves and belts
When using a straight edge to check sheave alignment, you should make sure the maximum misalignment does not exceed __________ per foot of belt span
1/16”
You are checking for _________ when you have a dial indicator reading off of one of the sheave groove faces.
Sheave runout
When using a deflection gauge to check for proper belt tension, you need to set the force applied o-ring and the other o- ring to the proper deflection distance for that belt.
True or false
True
Before checking the belt for proper tension, you should always rotate the belt and sheaves a few turns.
True or false
True
Quarter turn belts :
A maximum speed ration of 2.5:1
A centre distance of 5.5 times the sum of the large sheave diameter plus its face width
It’s centre line of the horizontal shaft above the centre line of the vertical shaft
All of the above
All of the above
If a belt is snaking from one sheave to the other while running it indicates?
Sheave runout
Sheave misalignment
Shaft runout
All of the above
All of the above
Standard belts are designed to run at a maximum temp of ______ degrees C
60
Synchronous belts are timing belts.
True or false
True
Synchronous belts are about 98% efficient and need less tension then the standard v belts.
True or false
True
Synchronous belts need _____ degrees of arc contact on the sprocket and ______ teeth engaged
60 degree arc contact
6 teeth engaged
If you are using plastic sheaves you are in a ?
Light duty environment
Chain sprockets are described by letters A B C D. These letters refer to the hub ______
Class
The minimum amount a roller chain can be shortened is _____ pitch?
1
A modified leaf chain that forms a tooth pattern when assembled is a _______?
Silent chain
A type d sprocket means what?
Split hub
A chain designated #120-2 has a pitch of _______?
1 1/2”
The recommended lubrication system for drives of moderate speed and load are_______?
Oil bath
When ever possible, install horizontal chain so that it runs with which strand tight? Top or bottom
Top strand tight
Idler sprockets should ________?
Increase the tension in the slack side of the chain
A type B should be mounted with the hub less face next to the ______?
Bearing
What is the installed sag in the bottom strand for a 125” centre to centre distance and running at high speed?
Sag in “ = c to c distance x % of sag allowed
2.5” to 3.75”
A chain drive with misalignment would have noticeable wear on the chain ______?
Side plates (insides)
A #2080 chain is a
Double strand chain with a 2” pitch
A drive has a sprocket with 24 teeth and a driven sprocket with 32 teeth. The c to c is 33” . What is the approximate length of chain needed for the drive, if the chain size is 100 roller chain?
C to C x 2
Count half teeth on each sprocket. Add together and multiply by chain pitch
Add c to distance and sprocket wrap
33 x 2 = 66
24/2= 12 32/2= 16
12+16 x 1.25 (100p) = 35
66 + 35 = 101”
A double pitch chain with a regular pitch sprocket (single pitch), how would you get even wear on all teeth?
Use 2 odd numbered tooth sprockets
Sintered bushing chain has what characteristic?
Last 5 times longer than standard chain
Rollerless chain has a designation of _____ when chain is above a 1/2” pitch?
5
When selecting a chain you should consider which of the following?
Horse power
Driver and driven shaft speeds
Operating environment
All of the above
All of the above
When ordering a sprocket you need to know:
Class of hub and size of chain
The pitch and number of teeth
Of teeth need to be hardened
Weakest link in a roller chain is the ______?
1 pitch offset link
Multiple strand chain is used when ______ and _______ for single chain?
Speed is to high
Or
Load is to great
O-ring chain keeps out contaminants, sealed for life and last about 10 times that of standard chain.
True or false
True
Silent chain is used in high horse power applications and where there is limited space for the drive.
True or false
True
Alignment of chain drive shafts and sprockets must be corrected in the horizontal and vertical planes which include offset and angular misalignment
True or false
True
The split in a master link spring clip should face against the direction of travel.
True or false
True
Forced lubrication is used on heavily loaded drives operating above the speed limits of the bath lubrication system.
True or false
True
If the teeth on a sprocket are hooked or thinned down and / or the chain has been exposed to excessive loading, you must:
Change the sprocket
Change the chain
Check for misalignment
All of the above
All of the above
A chain drive should have 120 degrees of contact with the small sprocket or a speed ratio of 3:1
True or false
True
A double single sprocket is designed to be used with a 2 strand chain.
True or false
False
A double single sprocket is used for 2 single chains moving separate parts
Keyless bushings are used in places where good balance is needed of the drive sprocket and also where there is no keyway.
True or false
True
When installing a cylindrical bore sprocket hub, you need to keep the dial readings to _______ for runout?
.002” or less
Broken roller chains or sprockets are a sign of ______ or _______
Shock or overloading.
A stiff chain is a sign of:
Faulty lubrication
Rust or corrosion
Misalignment
Ideally join the roller chain on the sprocket.
True or false
True
If you pull the chain on the backside of the sprocket and it pulls away from the sprocket, this is a sign of?
Worn pins and bushings
Align parallel shafts In a chain drive with a feeler bar.
True or false
True
Silent chain needs to be held on sprockets with guide plates or a flanged sprocket.
True or false
True
On roller chain, the roller diameter is approximately 5/8 of the pitch.
True or false
True
Speed ratio can be:
high speed shaft rpm/low speed shaft rpm
Or
Number of teeth on driven sprocket. /
Number of teeth on drive sprocket
True or false
True
A gear system that is exposed to overhung loads are?
Gears with bearings on only one side
A floating gear or shaft is?
On that floats axially to find it’s centre
Bevel gears are cut out of blanks like cones and ________?
Used on intersecting shafts
Hypoid gears are used in shafts crossing over, can be straddle mounted and need _____ lube?
E.P
Worm and wheels that are double throated have more _____________ with each other ( more depth)
Engagement
When setting up a worm and wheel reducer for contact between the worm and wheel, it should be slightly off centre toward the _________ side of the worm wheel?
Leaving
Planetary gears have the four main parts:
Sun
Carrier
Ring
And _________ gears
Planet
What cannot be held in a planetary gear system?
The planets
If you see pitting on the gears of a drive unit, this is an indication of:
Wrong lubricants
Heavy loads and low speeds
And __________ lubes
Contaminated
In gear reducer, lubrication is diverted to all areas needing lubrication by :
Scrappers
Dams
And _________?
Baffles
When using lead wire to check backlash, you should measure the wire on both sides of the tooth at the _______ line
Pitch
SM cycloid reducers must have the sheave mounted where?
As close to the bearing as possible
Backstops on conveyors are used to?
Stop reverse motion of the conveyor
When installing a idler between the 2 gears, you know that the final gear will turn the same direction as the first gear and the idler will not _________ the speed ratio of the gear system.
Change
When adjusting the correct preload of the worm and wheel tapered roller bearings you ________ shims between the bearing caps and reduction unit housing to increase the preload
Take out
All gear tooth profiles are involute form.
True or false
False
Can be involute or straight
The addendum is a greater length length than the dedendum.
True or false
False
Dedendum included clearance
Correct meshed gears always have pitch circles that coincide at the pitch point.
True or false
True
The shaft centre distance between a pair of meshing gears is the sum of their individual pitch circle diameters
True or false
False
When the revolutions of the driven gear increase, the Torque of that gear increases.
True or false
False speed increases
Rack and pinion gears have one gear with a straight pitch line while the other has a circular pitch line
True
False
True
Bevel gears develop both axial and radial thrust loads and need bearings that can accommodate both types of load.
True or false
True
2 meshing single helical gears of the same hand will only connect shafts that are parallel
True or false
False must be of opposite hand
Shafts crossing over at 90 must be same hand
When shaft mounted drives provide only part of the total reduction needed, the remainder will be reduced by ____________
V belts and sheaves
What is the primary type of lubrication system used in worm and wheel reducers?
Splash
What shaft conditions prevent shaft mounted reducers from being properly installed:
Out of round
Misaligned
And _______
Bent
The space between the gear sets mating teeth and the root is called the ________
Clearance
Double helical gears do not have what feature that the herringbone gear teeth have ?
A formed tooth at the tooth profile centre
Which gear type reduces the thrust?
Double helical
The outside diameter of a gear is equal to the root circle diameter plus _____ addendums
2
An 8 DP refers to a gear that has _______
8 teeth per inch of the gears pitch circle diameter
Backlash can be checked within a helical gear box by using the lead wire procedure which is?
Run lead wire between the mating teeth
Recover the wire and measure the thickness at the deformed regions at the pitch line
To ensure correct mesh pattern between worm and wheel reduction you must :
Assemble and install worm shaft and bearings with proper shim pac to get correct pre load
Add light coat of pursion blue to WORM
Mount worm wheel and bearings. Use proper shim pack for bearing clearance
Rotate worm in proper direction wile applying resistance to the worm wheel
Check contact pattern and adjust with shims moving from side to side until contact pattern slightly toward leaving side of worm wheel
True or false
True
Is a stainless steel chain in wet and corrosive areas.
True or false
True
Adding a jack shaft to a system will help:
Increase the arc contact on the small sprocket
Reduce the overall ratio of the original drive by dividing it up
And _________
Decrease chain and sprocket wear
A slip fit master link decreases the strength by ______%
30
