The ClutchAndrew HannaDan TaubDanny Zirkel
Que es clutch?O Is it:
O A: a firm grasp?O B: a handbag without handles?O C: A group of eggs fertilized at the same
time, typically laid in a single session and (in birds) incubated together?
O D: a device that enables two revolving shafts to be joined or disconnected as required, esp one that transmits the drive from the engine to the gearbox in a vehicle ?
O E: all of the above?
Exploded!
Our Exploded
Back Plate / HubO Purpose:
O Connected to main shaft; transfer rotational energy from clutch basket to transmission.
BasketO Purpose:
O House the clutch plates; connected to the primary chain.
O Specs:O 48 teeth (engine sprocket has 18 teeth)O Gear ratio of 2.67/1
Friction Plate / Smooth Plates
O Purpose:O Friction plate: connected to clutch basketO Smooth plate: connected to inner hubO When clutch engaged: both spin freelyO When clutch not engaged: prevent
slippage with surface friction between plates (allow transfer of energy between basket and hub)
O Specs:O Plate thickness: 1/8 inO Plate diameter: 4.95 in
Primary ChainO Purpose:
O Transfer rotational energy from engine sprocket to clutch basket.
O Specs: O 3/8 x 7/32 inO 62 linksO Duplex
Cups / SpringsO Purpose:
O Compress the clutch plates together when clutch is not engaged.
O Specs:O Free length: 1.4 inO Compressed length (for testing): .77
inO Force applied during testing:
40lbs=177.93NO Spring constant: 761lbs/ft =
11,120.55 N/m
LeverO Purpose:
O Utilize mechanical advantage to lower the force needed on the handle.
O Specs: O Distance from pivot to push rod: .25
inO Distance from push rod to applied
force from cable: 2.5 inO Mechanical advantage: 5:1
Push Rod / Adjustment Screw
O Purpose: O Transfer of mechanical energy from
the lever to the pressure plate.O Specs:
O Length: 7.01 inO Diameter: .156 in
The Science BehindO How much force is required to depress
the clutch?O (Measurements based on ’58)O Force to release clutch without any
mechanical advantage: ~200lbsO Divide by mechanical advantage of lever
(5:1): ~40lbsO Divide by mechanical advantage of
clutch handle (2.5/.6 =4.2:1): ~9.5lbs (with no friction)
SlippageO Symptoms: Engine revs but no
corresponding acceleration.O How: Clutch slippage is when the clutch
plates are slipping across each other, rather than engaging and transferring engine torque to the drive train.
O Why: The cause can be a poorly adjusted clutch, or worn springs, or worn plates.
O Our clutch slips at between 6 and 9 ft lbs with well-compressed springs.
’58: The Devil’s DanceO Clutch was heavy, noisyO During testing, clutch cable
“snapped”O Solution 1: We used emory paper to
smooth out the teeth on the driven clutch plates, then buttoned up and attached new cable
O Consequences: “Oh, well that’s just awful.”
‘58 (continued)O Solution 2: We lubed cable to stop
noise; tightened adjustment screw for better push-rod connection
O Consequences: “…still worse than it’s ever been.”
O Solution 3: Run cable along a straighter path (reduce friction)
O Consequences: “The best this clutch has ever felt!”
‘59: Re-assemblyO Original parts:
O Back plate / hubO LeverO PushrodO Springs/cups/screwsO Adjustment screws
O New parts:O BasketO Friction platesO Driven platesO Cable
Re-assembly
Clutch Photoshoot ‘13
Dis wus the best present-A-tion ah eva
did see!
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