US3874253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Waddington drive
Assignee: Individual
•
Filing: 1973-05-31
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Granted: 1975-04-01
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Expires: 1993-05-31
Abstract
Abstract An improved Waddington drive is positioned within a hub, such as a bicycle hub, and connected between the hub and an operatorpowered sprocket. A series of planet gears are journaled for rotation in the rotating hub and all engage a fixed sun gear on a mounting shaft. The planet gears are connected by means of oneway clutches to a series of followers which engage a cam mounted on the sprocket so that it has a variable eccentricity. A coiled spring connected between the input sprocket and the cam varies the eccentricity in response to the torque reaction forces between the cam and the followers. This maintains the inputoutput ratio of the hub at a value enabling constant input torque irrespective of variations in output torque requirements.
Inventors
- 👤 Clive Waddington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:43
CPC Classifications
F; F16; F16H; F16H29/00; F16H29/22
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
181 words
A stepless variable-stroke drive comprising: an input element journaled for rotation and having a generally cylindrical cam means displaceable between a first position wherein its effective center is eccentric with respect to the axis of rotation of said input element and a second position wherein the effective center is closer to said axis; an output element journaled for rotation; at least one planet gear journaled in said output element; a nonrotatable gear engaging said planet gear for providing a torque reaction therewith; crank arm means having a follower at one end engageable with said cam means for pivoting cyclic movement of the crank arm means about the other end thereof; a one-way clutch connecting the other end of said crank arm means to said planet thereby causing said planet to revolve about the rotational axis of said output element at an inputoutput speed ratio generally proportional to the distance of the effective center of the cam means from the axis of said input element; and means responsive to the torque across said drive for displacing said cam means between said positions.
Claim 2
Dependent Claim
181 words
A stepless variable-stroke drive comprising: an input element journaled for rotation and having a generally cylindrical cam means displaceable between a first position wherein its effective center is eccentric with respect to the axis of rotation of said input element and a second position wherein the effective center is closer to said axis; an output element journaled for rotation; at least one planet gear journaled in said output element; a nonrotatable gear engaging said planet gear for providing a torque reaction therewith; crank arm means having a follower at one end engageable with said cam means for pivoting cyclic movement of the crank arm means about the other end thereof; a one-way clutch connecting the other end of said crank arm means to said planet thereby causing said planet to revolve about the rotational axis of said output element at an inputoutput speed ratio generally proportional to the distance of the effective center of the cam means from the axis of said input element; and means responsive to the torque across said drive for displacing said cam means between said positions.
Claim 3
Dependent Claim
47 words
A stepless variable-stroke drive as in claim 1 wherein said cam means is contoured around its periphery to produce a first rate of pivoting cyclic movement of the crank arms for said first position and a second lower rate of pivoting cyclic movement for said second position.
Claim 4
Dependent Claim
96 words
A stepless variable-stroke drive as in claim 1 wherein said input element comprises: an input element rotatable about a central axis having an integral cylindrical disc at one end, the axis of said disc being offset from said central axis; and a generally cylindrical cam having a circular opening by which said cam is journaled over said disc. the axis of said circular opening being offset from the effective center of said cam whereby rotation of said cam relative to said disc varies the distance of the effective center of said cam from said central axis.
Claim 5
Dependent Claim
64 words
A stepless variable-stroke drive as in claim 3 wherein the effective center of said cam is offset from the axis of said disc an amount equal to the offset between the axis of said disc and said central axis whereby said cam may be pivoted so that its effective center moves through a circular arc to a position of eccentricity with said central axis.
Claim 6
Dependent Claim
45 words
A stepless variable-stroke drive as in claim 3 wherein the exterior surface of said cam has first and second contours, the first contour acting to pivot said follower during positions of minimum eccentricity and the second contour pivoting said follower for positions of greater eccentricity.
Claim 7
Dependent Claim
58 words
A stepless variable-stroke drive as in claim 5 wherein said second contour is semicircular having its axis coincident with the effective center of said cam and the first contour being semicircular and having a radius greater than the radius of said second contoured surface, said contoured surfaces each extending for approximately 180* of the periphery of said cam.
Claim 8
Dependent Claim
39 words
A stepless variable-stroke drive as in claim 3 further comprising means for damping the rotation of said cam relative to said disc whereby variations in input-output ratio in response to rapid cyclic changes of input torque are effectively damped.
Claim 9
Dependent Claim
71 words
A stepless variable-stroke drive as in claim 7 wherein said damping means comprises: an arcuate groove formed in the periphery of said disc; a pin secured to said cam and extending inward into said groove; means for sealing the periphery of said groove, said groove being fillable with a viscous material thereby damping movement of said cam through said groove in response to rotation of said cam relative to said disc.
Claim 10
Dependent Claim
44 words
A stepless variable-stroke drive as in claim 8 wherein said sealing means comprises circumferential grooves in the periphery of said disc on both sides of said arcuate groove and resilient O-rings received in said grooves for sealingly engaging the circular opening in said cam.
Claim 11
Dependent Claim
58 words
A stepless variable-stroke drive as in claim 3 wherein said torque-responsive means comprises: an element nonrotatable with respect to said rotatable input element; a second element journaled on said input element and relatively rotatable with said cam; and yieldable urging means connected between said first and second elements for urging said cam to a position of maximum eccentricity.
Claim 12
Dependent Claim
93 words
A stepless variable-stroke drive as in claim 10 wherein said cam has a tab extending in an axial direction, said second element comprises a generally cylindrical element having a central opening for journaling about said input element and a notch on the periphery for receiving one end of said yieldable urging means, said second element having a radially extending slot receiving said tab, whereby said second element rotates with said cam irrespective of the variation in the distance of the tab on said cam from the axis of rotation of said second element.
Claim 13
Dependent Claim
71 words
A stepless variable-stroke drive as in claim 11 wherein said first element comprises a disc with an outer flange having a notch for receiving the opposite end of said yieldable urging means and wherein said yieldable urging means comprises a coiled spring with a rectangular cross section having a first end connected to the notch in said second element and a second end connected to the notch in said first element.
Claim 14
Dependent Claim
32 words
A stepless variable-stroke drive as in claim 12 wherein said first element comprises means for adjustably positioning said spring-receiving notch of said first element relative to the axis of said input element.
Claim 15
Dependent Claim
108 words
A stepless variable-stroke drive in claim 13 wherein: said first element comprises a flange secured to said input element and an outer ring supported by and rotatable around said flange, said outer ring having said spring-receiving notch; sAid adjustable means comprises a peripheral surface formed on said flange, an arm pivotally secured to an element on said ring, the distance from the pivotal mounting of said arm to the end thereof being greater than the distance from the pivotal mounting radially inward to said peripheral surface, and means yieldably urging said arm into engagement with said peripheral surface thereby holding said ring relative to said flange by friction.
Claim 16
Dependent Claim
37 words
A stepless variable-stroke drive as in claim 14 wherein said peripheral surface on said flange comprises an integral ring having a plurality of spaced notches around its periphery providing a detent for the end of said arm.
Claim 17
Dependent Claim
57 words
A stepless variable-stroke drive as in claim 1 wherein: said cam means has a generally cylindrical outer follower engaging surface; said followers comprise rollers journaled to said crank arm means and engaging said cam surface whereby movement of said cam means pivots said followers; and means for maintaining said followers in engagement with said cylindrical cam surface.
Claim 18
Dependent Claim
47 words
A stepless variable-stroke drive as in claim 16 wherein said means for maintaining said rollers in engagement with said cam surface comprises a circular ring enclosing the periphery of said rollers and having a predetermined diameter which maintains the rollers in engagement with said cylindrical cam surface.
Claim 19
Dependent Claim
21 words
A stepless variable-stroke drive as in claim 17 further comprising a one-way clutch between said input sprocket and said input element.
Claim 20
Dependent Claim
64 words
A stepless variable-stroke drive as in claim 18 wherein said driving means comprises: a first gear concentric with an fixed to said input element; and a second gear concentric with and fixed to said inertia wheel and meshing with said first gear, the diameter of said first gear being substantially greater than the diameter of said second gear thereby providing a substantial speedup ratio.
Claim 21
Dependent Claim
48 words
A stepless variable-stroke drive as in claim 16 wherein said means for maintaining the rollers in engagement with said cam surface comprises torsion springs connected to one end of said crank arm means and to said output element for pivoting said followers into engagement with said cam surface.
Claim 22
Dependent Claim
35 words
A stepless variable-stroke drive as in claim 1 wherein said input element comprises a drive sprocket adaptable to engage an operator-driven chain and wherein said output element comprises the hub of a spoked vehicle wheel.
Claim 23
Dependent Claim
42 words
A stepless variable-stroke drive as in claim 1 further comprising: an inertia wheel journaled for rotation; and means connected to said input element for driving said inertia wheel at a high rate of speed in response to rotation of said input element.
References Cited (Backward Citations)
US2168600A
Cited
US3324746A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |