Martin Sprocket & Gear Variable Pitch Sheaves - Manual (Page 2)

Martin
Mounting and Adjusting Procedure
Variable Pitch Sheaves
Double Groove Sheaves With External Key:
Mounting:
1. Make sure that the shaft, sheave bore, keys and keyways are free of burrs and paint.
2. Remove key “H” from sheave. Unscrew flanges until setscrew “R” is visible. If setscrew “R” is at an angle, flange may have to be
removed in order to tighten it.
3. All sheaves should be mounted on the motor or driving shaft with the end containing the setscrew “R” toward the motor. If
setscrew “R” is at an angle, mount away from motor.
4. Fit shaft key “C” between sheave and shaft, and lock setscrew “R” in place. Wrench
torque 110 in.-lb. minimum - 130 in.-lb. maximum. Replace outboard flange.
5. Be sure the center flange of both the driving and driven sheaves are in alignment
and shafts are parallel.
6. Total axial and parallel misalignment must not exceed 1⁄4°.
Adjusting:
Each flange of the sheave has a small notch on the O.D. of the flange. This mark is
located directly over the keyway on the two adjustable flanges and over one of the
keyways on the non-adjustable (center) flange. To obtain proper adjustments:
1. Loosen setscrews “V” in moving flanges and pull out key “H”. (This key projects a
small amount to provide a grip for removal.)
2. Rotate both movable flanges inward until they touch the center flange.
3. Locate the notch over the keyway on the center flange.
4. Open each movable flange until its notch is adjacent to the notch on the center flange. Be certain that neither movable flange is
opened more than one full turn.
5. From the position obtained in Step 4, open each movable flange the same number of full or half turns until the desired number of
turns is obtained. Do not open more than five full turns for “A” belts or six full turns for “B” belts. (Except 2VP36 - 5 turns.)
6. Replace key “H” and tighten setscrews “V”. Wrench torque 110 in.-lb. minimum to 130 in.-lb. maximum.
7. Put on belts and adjust belt tension. (Do not force belts over flanges.)
8. Future adjustments should be made by loosening the belt tension and increasing or decreasing the pitch diameter of the sheave by
half or full turns as required. Readjust belt tension before starting drive.
9. Two groove sheaves must have both halves adjusted by the same number of turns from the position established in Step 4 to ensure
the same pitch diameter.
10. Be sure that all keys are in place and that all setscrews are torqued properly before starting drive. Check setscrews and belt
tension after 24 hours service.
WARNING: Because of the possible danger to person(s) or property from accidents which may result from
the improper use of products, it is important that correct procedures be followed: Products must be used in
accordance with the engineering information specified in the catalog. Proper installation, maintenance and
operation procedures must be observed. The instructions given above must be followed. Inspections should
be made as necessary to assure safe operation under prevailing conditions. All rotating power transmission
products when used in a drive are potentially dangerous and must be guarded by the user as required by
applicable laws, regulations, standards, and good safety practice. (Refer to ANSI Standard B15.1.)
DOUBLE GROOVE WITH EXTERNAL KEY
R
V V
H
OD Notched
Here
C
Key “H” projects to provide a grip for removal.
Do not operate sheave with flange projecting
beyond the hub end.