59 terms

Construction Equipment Power Trains

CM-36 #859
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Does a power shift transmission use a torque converter?
Yes; It is designed to provide for high-speed shifting through hydraulically actuated clutches
What are the 4 shafts of a power shift transmission?
1. Reverse clutch shaft
2. Forward clutch shaft
3. Spline shaft
4. Bevel pinion shaft
What does the forward clutch shaft of a power shift transmission consist of?
Of first and second speed drive gears riding on bushings; It is welded to dual hydraulic clutch pad assemblies
Where are the 2 straight roller bearing located on which the spline shaft rotates?
The rear bearing is mounted in the transmission case and the front bearing is mounted in the transmission cover
What does the bevel pinion shaft consist of?
High and low range gears keyed to the shaft
What are the 2 pistons which make up the core of a forward and reverse hydraulic clutch?
1. Accelerator piston
2. Force piston
What valve in a modern power shift transmission directs main oil pressure to the range selector valve and thus causes it to direct main oil pressure to the desired clutch assembly?
A spool valve, or pilot control valve, which is actuated by the gearshift lever
What 3 members compose the planetary gearset in some types of power shift transmission?
1. Sun gear
2. Ring gear
3. Planetary carrier
Are the planetary pinion gears in the planetary steering system composed of 2 gears of different sizes, which are machined into 1 piece?
Yes, and 2 sun gears are also included in the system
What type of pivot brakes are used on tracked equipment?
Multiple disc type
How are the steering brake levers for pivot brakes operated?
By pulling them fully to the rear
What is a hydrostatic drive?
An automatic fluid drive that uses fluid under pressure to transmit engine power to drive wheels or tracks
What are the 2 basic hydrostatic principles of the hydrostatic drive?
1. Liquids have no shape of their own
2. Liquids are incompressible
Are several pistons used in a hydrostatic drive to transmit power?
Yes, 1 group in the pump that sends power to another group in the motor
What is a pump or motor with a movable swash plate called?
A variable-displacement unit
What is a pump or motor with a FIXED swash plate called?
Fixed displacement unit
What are the 3 fundamental factors that control the operation of a hydrostatic drive?
1. Rate of oil flow, which provide speed; 2. The direction of oil flow (direction); 3. Oil pressure (power)
What are the principal advantages of a hydrostatic drive?
1. Unlimited speeds and torque; 2. easy on-lever control 3. Smooth shifting 4. High torque availability 5. Shifts "on the go" 6. Flexible location (no drive lines) 7. Low maintenance 8. Reduced shock loads 9. Compact size 10. Elimination of clutches and large gear units
What is another name for the FNR valve in a hydrostatic drive?
The displacement control valve
What determines the distance that the pistons reciprocate in and out of the cylinder block in a hydrostatic forward drive operation?
The angle of the swash plate of the pump, which regulates the volume of oil displaced per pump revolution
What devices keep trapped oil in the cylinder block of the pump, in the motor, and in the connecting lines between the pump and motor, when the speed control lever in is neutral?
2 check valves located in the pump end capability
What controls the pump pressure when the hydrostatic drive system is in neutral? - The high charge pressure control vavle, which is located at the charge pump
When the speed control valve is moved into reverse, what happens?
The spool in the FNR valve moves out of neutral, allowing pressure oil to flow into the lower servo cylinder, so that the swash plate is tilted forward
Does the pump drive shaft in a hydrostatic drive always rotate clockwise?
Yes
What are the 2 major components of the undercarriage of crawler-mounted equipment?
The track assembly and the track frame
What is track pitch?
The length of the track
What is the most common type of track shoe?
The grouse shoe
What type of track shoe is mainly used in rocky areas, such as on coral beaches or in rock quarries?
The extreme service track shoe
What are the 2 types of track frame roller?
Carrier rollers and track rollers
What is the front idler?
A spring-loaded track chain support, which is mounted on guides or slides allowing it to move back and forth inside the track frame as the tractor passes over any uneven terrain
What is the purpose of the recoil spring, which is a large coil spring located in the track frame?
To absorb shock from the front idler
What are the 3 types of track guiding guards?
Front guiding guards, rear guiding guards, and center guiding guards
How can the proper track tension be determined?
By placing a straightedge ruler over the front carrier roller and idler with all slack removed from the rest of the track, and measuring from the top of the track shoe to the bottom edge of the straightedge
Do track pins and bushings require periodic lubrication?
No, because they are hardened
How is the track tension released prior to track removal?
Either by manually backing off of the track adjuster, or by loosening the vent screw on the hydraulic track adjuster
How is the track master pin identified?
By means of a locking device or by a hole that is drilled in its end that distinguished it from other pins in the chain.
What is the usual type of front-mounted winch used on tactical equipment?
A jaw-clutch worm-gear winch
What is the purpose of the shear pin in the universal joint yoke of a jaw-clutch worm-gear winch?
The shear pin has a predetermined breaking strength allowing for it to shear whenever the winch becomes overloaded
What are the 2 brakes that provide for control of the winch drum?
The worm brake shaft and the shifter bracket brake
What type of wire rope is manufactured by shaping the strands, or wires, to conform the curvature of the finished rope before laying up?
Preformed wire rope
How many strands and wires are in a ½-inch 6 x 37 wire rope?
Six strands with 37 wires per strand
What does Seale construction of wire rope consist of?
It refers to the design arrangement of a strand where larger diameters wires are used on the outside of the strand in order to resist abrasion, and smaller wires are used on the inside to yield flexibility
What does Warrington construction of wire rope consist of?
It refers to the design arrangement of a strand where alternate wires are large and small in order to combine exceptional flexibility with resistance to abrasion

What are the 3 types of wire core? - Fiber, wire strand, and independent wire rope
What are the characteristics of plow steel wire rope?
It is strong and tough, with a tensile strength of 220,000 to 240,000 psi, suitable of hoisting, hauling, and logging operations
What does a left long lay refer to?
A wire rope lay in which the wire in the strands and the strands in the rope are laid to the left
What are the 2 most common types of wire rope?
6 x 19 and 6 x 37
What is the tensile strength of a wire rope?
The strength is required to withstand a certain maximum load applied to the rope
What is the SWL (Safe working load) for a wire rope? - The load can be applied yet still gain the most efficient service, and prolong the working life of the rope
What is the correct direction of coiling for right lay wire rope?
Clockwise (left lay counterclockwise)
On which type of hoist drum is there a sufficient control to wind wire rope properly, whether it is right or left lay rope?
On a grooved drum
How is the fleet angle formed?
By running the wire rope between a sheave and a hoist drum whose axles are parallel to one another
How is the correct number of seizing to be applied on wire rope determined?
It is equal to approximately 3 times the diameter of the rope
How far appart should the seizing be placed on a 2 x ¾-inch-diameter wire rope?
1 ½ inch
When should wire rope be replaced due to deterioration?
When is has 1/3 of the original diameter of the outside individual wires
How many grades does Type II, Protective Lubricating Oil for Chain, Wire Rope, and Exposed Gear come in?
3: Grade A for cold weather (under 60F), Grad B for warm weather (60F to 80F), Grade C for hot weather (80F and up)
Which attachment is most commonly used to attached dead ends of wire ropes to pad eyes or similar fitting on cranes and earthmoving equipment?
A wedge socket
What is "spelteirng"?
Attaching a socket to a wire rope by pouring hot zinc around it
What is the formula for caculating how many rope clips are needed to make and eye in a wire rope?
X= 3 x diameter + 1
How much of a wire rope's strength can be held by wire rope eyes with thimbles and by wire rope clips?
Approximately 80 percent of the wire rope strength
How is a swaged connection made in wire rope?
By compressing a steel sleeve over the rope using a hydraulic press.
How many wraps should be made around both sides of a hook when mousing the open part of a hook?
8-10