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US 4,069,718 AGranted
Speed change device
AssigneeThe United States of America as represented by the Secretary of the Army
InventorErwin F'Geppert
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AssigneeThe United States of America as represented by the Secretary of the Army
InventorErwin F'Geppert
Estimating the term…
A mechanical speed change device designed to occupy minimum space in the ial direction. In operation, a ball type cam follower simultaneously tracks sinuous cam grooves in the drive and driven members. The lead angles of the respective cam grooves are different so that a given axial displacement of the cam follower requires different rotational movements of the drive and driven members. Therefore a given rotational speed of the drive member produces a different rotational speed of the driven member.
A speed change device comprising drive and driven members arranged on a common rotational axis;
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
For conveying rotary motion: with intermediate members guided along tracks on both rotary members
Gearing
Term ended 24 Jan 1995 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
Conventional speed change devices somtimes employ spur gears carried on parallel shafts. Such shaft-gear arrangements require consideralbe radial space for the gears and considerable axial space for the shaft bearings. The present invention seeks to provide a speed change device that minimizes the radial space requirement without unduly increasing the axial space requirement.
FIG. 1 is a longitudinal sectional view taken through one embodiment of the invention.
FIG. 2 is longitudinal sectional view taken through another embodiment of the invention.
The device shown in FIG. 1 comprises a stationary member 10 that includes a sleeve 12 defining a central rotational axis 14 for a shaft-type drive member 16. Shaft member 16 connected at its left end to any suitable powered device (not shown). The illustrated portion of shaft member 16 is provided with an endless sinuous cam groove 36 and an endless radial groove 37. The sinuous groove acts as a track for a cam follower ball 32 trapped within an axial slot 40 in sleeve section 12 of stationary member 10; rotation of shaft member 16 around axis 14 produces axial motion of ball 32 back and forth along slot 40. The aforemention radial groove 37 register with a second radial groove 39 formed in the interior surface of driven member 18; closely-spaced anti-friction balls 24 are arranged in grooves 37 and 39 to form an anti-friction connection between members 16 and 18. Member 18 is able to move rotationally on member 16 but not axially.
Anti-friction balls 24 absorb axial thrust forces that might otherwise tend to produce relative axial displacement of members 16 and 18. Initial loading of balls 24 into the raceway (i.e. grooves 37 and 39) may be accomplished by first removing a plug 26 that is suitably threaded or otherwise secured in sleeve section 22 of member 18.
Drive forces are transmitted from drive member 16 to driven member 18 by means of the cam follower ball 32. As seen in FIG. 1, the ball has its outer segmental portion disposed in a sinuous cam-forming groove 34 in member 18, and its inner segmental portion disposed in a sinuous cam-forming groove 36 in member 16. The ball may be loaded into the cam grooves through an opening that is subsequently closed by a plug 38.