VARIABLE SPEED DRIVE MECHANISMS
First Claim
1. A variable speed drive mechanism including a rotatable drive member;
- a series of rotary elements rotatably engaging the drive member to be rotated thereby along a substantially circular engagement zone of variable diameTer on the drive member; and
a driven member rotatable in response to rotation of the rotary elements, at least said zone on the drive member being resiliently flexible in a direction transversely of its plane of rotation.
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Accused Products
Abstract
A variable speed drive mechanism is disclosed wherein a rotatable drive member imparts movement to a driven member through a cage containing a series of rotary elements sandwiched between the two members, at least one of which is resiliently flexible. The elements engage a circular track comprising grooves of concave cross-sectional configuration disposed on the members. The grooves are of slightly larger diameter than the elements so that on flexing one of the members the effective radius of contact between the elements and the groove walls may be varied and the rotational speed imparted to the other member varied accordingly. A single directional variable speed unit is thus provided. In another unit two sets of rotary elements of the aforesaid kind are linked in back to back relationship with their cages interconnected to provide a variable speed unit with a greater speed range which passes through zero and is reversible. These units not only require fewer components than the conventional comparable unit, but the components are also relatively simple and cheap to manufacture.
179 Citations
15 Claims
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1. A variable speed drive mechanism including a rotatable drive member;
- a series of rotary elements rotatably engaging the drive member to be rotated thereby along a substantially circular engagement zone of variable diameTer on the drive member; and
a driven member rotatable in response to rotation of the rotary elements, at least said zone on the drive member being resiliently flexible in a direction transversely of its plane of rotation.
- a series of rotary elements rotatably engaging the drive member to be rotated thereby along a substantially circular engagement zone of variable diameTer on the drive member; and
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2. The mechanism of claim 1 wherein the rotary elements are barrel shaped or similarly contoured rollers and their track defined between two substantially flat or slightly curved surfaces.
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3. The mechanism of claim 1 including a second engagement zone located on a stationary member which together with the drive member defines a track along which the rotary elements may move.
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4. The mechanism of claim 3 wherein the engagement zones comprise circular grooves of concave cross-sectional configuration located on the drive and stationary members respectively, in which grooves the rotary elements are confined to move.
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5. The mechanism of claim 1 wherein the rotary elements are spheres of slightly smaller diameter than that of the grooves.
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6. The mechanism of claim 1 wherein the rotary elements are rotatably carried in a cage or carriage.
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7. The mechanism of claim 1, wherein the driven member is resiliently flexible in a direction transversely of its plane of rotation.
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8. The mechanism of claim 1, wherein at least those parts of the drive and driven member which define the track between them are in the form of resiliently flexible discs.
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9. The mechanism of claim 8 wherein the flexible discs are Belville springs.
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10. The mechanism of claim 3 wherein the rotary elements are contained between two discs of convex configuration in cross section in back to back relationship to define a circular track which becomes progressively flatter in the direction of the mid-points of the discs.
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11. The mechanism of claim 1 wherein at least one of the flexible elements is flexible in a direction parallel to its plane of rotation.
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12. The mechanism of claim 6 including a second carriage and series of said rotary elements, the second carriage being connected to the first carriage for rotation therewith and the rotary elements of the second carriage being rotatable in a substantially circular track of which the diameter is variable, the track being defined between a second drive member which is flexible and which is connected to the first drive member for rotation therewith and a second member adapted for rotation in response to rotation of the rotary elements of the second carriage.
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13. The mechanism of claim 12, wherein the initial driving force may be applied to any one of the parts which are referred to as the first drive member, the carriages, the second drive member, or the second driven member.
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14. The mechanism of claim 12 wherein the carriages comprise conventional ball races.
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15. The mechanism of claim 12 wehrein at least one of the carriages is pre-loaded.
Specification