US3479887A - Repeat cycle release mechanism - Google Patents

Description

Nov. 25, 1969 s, oss 3,479,887

REPEAT CYCLE RELEASE MECHANISM Filed April 10, 1968 INVENTOR. SHELDON I. ROSS ATTORNEYS United States Patent 3,479,887 REPEAT CYCLE RELEASE MECHANISM Sheldon I. Ross, Moline, lll., assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Ohio Filed Apr. 10, 1968, Ser. No. 720,132 Int. Cl. F16h 5/74 US. Cl. 743.52 8 Claims ABSTRACT OF THE DISCLOSURE A release mechanism having a support and a shaft adapted to be rotated in opposing first and second directions. First and second rotatable members are located on the shaft in axially spaced relationship therewith, with the first member being fixed to the shaft for rotation therewith and with the second rotatable member being loosely mounted on the shaft for rotation with respect to the shaft. A coil spring loosely surrounds the shaft between the rotatable members, with the coil spring having each of its opposing ends mechanically coupled to a different one of the rotatable members, and being arranged so as to resiliently bias the second member for rotation in the first direction and to resiliently bias the first member for rotation in the second direction. Locking means normally locks the second member against rotation in the first direction so that as the first member is rotated in the first direction the energy stored in the coil spring increases to increasingly bias the second member in the first direction. A lock release carried by the first member releases the locking means after a predetermined angular rotation of the first member in the first direction, whereupon the energy stored in the coil spring is released to drive the second member in the first direction. Stop members prevent more than 360 of respective angular rotation between the rotatable members in either of the two directions.

The present invention relates to a release mechanism that provides specific timed cycles for associated timing devices, and, more particularly, to the release thereof for automatically and periodically providing repetitive cycles. The present invention is particularly adapted for operation with timers and it will be discussed with particular reference thereto; however, the invention has somewhat broader applications and it may be used wherever the need arises for a specific timed cycle, repeatable from a predetermined starting point.

Timing devices for providing specifically timed cycles have become an important component in a wide variety of control applications. Because of their importance and Wide spread use, simplification and ease of manufacture are prime requisites.

Typical of such timing devices are those that are driven by a Inechaical means such as a motor or a ratchet wheel. The motor is a continuous drive in one direction with the torsion spring being wound as the motor drives in the one direction. The ratchet wheel is stepped intermittently in one direction with a detent preventing movement in the opposite direction so as to gradually wind the torsion spring. At any time the motor or ratchet Wheel may be decoupled and the torsion spring drives the device in the opposite direction to a home position.

There are no provisions in such timing devices for repeating the cycle without first decoupling the drive mech- Patented Nov. 25, 1969 anism allowing the torsion spring to reset or return the mechanism to the start or home position. Only when the device is at the start position can the drive mechanism be restarted to provide a second cycle or program. This resetting requires additional devices to restart the drive for the subsequent timing cycles, or a time delay is required to guarantee that the mechanism has completely returned to its starting point.

In brief, the release mechanism, which will be thoroughly described hereinafter, comprises a compact repeat cycle release mechanism which features simplicity of operation and ease of manufacture. The release mechanism provides, in a single structure, recycling of the structure from a predetermined starting point; (1) upon the loss of energizing driving power to the device; (2) upon a manual interruption in the timing cycle before the completion thereof; and (3) upon a completion of such a timing cycle. Thus, the timing cycle duration of this mechanism is measured from the same prescribed point of time for all conditions of operation.

In accordance with the present invention, there is provided a release mechanism comprising: a shaft adapted to be rotated in opposing first and second directions; first and second rotatable members located on said shaft in axially spaced relationship therewith, said first member being fixed to said shaft for rotation therewith and said second member being loosely mounted on said shaft for rotation with respect to said shaft; a coil spring loosely surrounding said shaft between said rotatable members, said coil spring having each of its opposing ends mechanically coupled to a different one of said rotatable members and being arranged so as to resiliently bias said second member for rotation in said first direction and to resiliently bias said first member for rotation in said second direction; locking means for normally locking said second member against rotation in said first direction so that as said first member rotates in said first direction the energy stored in said coil spring increases to increasingly bias said second member in said first direction; and, lock release means carried by said first member for releasing said locking means after a predetermined angular rotation of said first member in said first direction, whereupon the energy stored in said coil spring is released to drive said second member in said first direction.

The principal object of the present invention is to provide a repeating cycle release.

Another object of the present invention, is to provide a release that permits a timing mechanism to repeat a timing cycle upon the completion of such a timing cycle.

Another object of the present invention is to provide a release that permits a timing mechanism to repeat a timing cycle from a predetermined starting point.

Another object of the present invention is to provide a release that permits a timing mechanism to start a timing cycle from a predetermined starting point upon the loss of energizing power to the timing mechanism.

Another object of the present invention is to provide a release that permits a timing mechanism to start a timing cycle from a predetermined starting point upon the manual interruption of the preceding timing cycle before the completion thereof.

These and other objects and advantages of the invention will become apparent from the following description of a specific example embodying the invention and the attached claims when taken in connection with the accompanying drawings illustrating the described speclfic example embodying the invention in which:

FIGURE 1 is an end view of the disclosed release mechanism in partial cut-away to more distinctly show the concepts of this invention, illustrating a partial completion of a timing cycle; and,

FIGURE 2 is a front view of the disclosed release mechanism also illustrating a partial completion of a timing cycle of this invention.

DESCRIPTION Referring now to the drawings which are for the purpose of illustrating the principles of this invention and not for the purpose of limiting the same, a release mechanism A constructed in accordance with this invention-is illustrated in a partially cut-away end view in FIGURE 1 to more distinctly illustrate the concepts of this invention, and in front view FIGURE 2.

FIGURES 1 and 2 show the release mechanism A of this invention partially through a timing cycle, with a shaft that is rotatable, shaft 10 having an end 11 extending through a support 12. Shaft end 11 is retained adjacent one face of support 12 by means of a suitable retaining clip 14, which can take the form of any number of such devices designed for such purposes. Axially aligned with clip 14 and on shaft 10, adjacent the other face of support 12, is a spacer 16. A small aperture 18 is provided in support 12, which aperture is suitable for retaining one end of a coiled spring, as will be detailed subsequently.

Abutting spacer 16 is a bearing surface of one face of a rotatable disc 20, which disc is loosely mounted on shaft 12 by means of a suitable bore through the center of the disc. A peripheral surface 21 of disc is provided with a multiplicity of angled teeth to form a ratchet suitable for opertaion with a locking pawl. A small aperture 24, suitable for retaining one end of a spring, is provided in disc 20 and its function will be indicated subsequently. An abutment 26, in the form of a stop pin, is fixedly attached to the other face 27 of disc 20. Face 27 is opposite to the face of disk 20 that abuts spacer 16. This abutment 26 is attached to face 27 of disc 20 so as to be aligned, radially, with a cooperating abutment, as will be detailed subsequently.

Coaxially and loosely surrounding shaft 10 and continguous to face 27 of disc 20, is coiled torsion spring 30, which is used to store energy. Spring 30 has a spring body 32, coiled counterclockwise with respect to disc 20, loosely surrounding shaft 10 and with an end 34 seated in aperture 24 of disc 20 for mechanical cooperation between disc 20 and the spring. A second end 36 of torsion spring 30 is adapted to be seated in a similar aperture in another rotatable disc 40.

Rotatable disc 40 is fixedly attached to shaft 10 so as to be rotatable with the shaft. A mounting collar 42 is aflixed to the outer face 43 of disc 40. Both disc 40 and collar 42 have suitable bores for passing shaft 10 therethrough. Disc 40 is effectively mechanically coupled to shaft 10 in a fixed space relationship to disc 20 by means of a locking screw 44 locking collar 42 to the shaft so as to retain spring 30 between the two discs. An aperture 45 in disc 40 retains second end 36 0f torsion spring 30.

A second abutment 46, in the form of a stop pin, is affixed to inner face 47 of disc 40 in radial alignment and for cooperation with abutment 26, which is afiixed to inner face 27 of disc 20. The function of abutments 26 and 46 is to define a predetermined amount of rotational movement of discs 20 and 40 with respect to each other, but not to exceed 360. A camming projection 48 carried on a peripheral surface 49 of disc 40 cooperates with a locking mechanism 50 so as to permit recycling of the release mechanism.

The relative locations of abutment 46 and camming projection 48, both carried by the disc 40, are selected with reference to each other so as to define a prescribed release cycle. Thus, it should be appreciated that the prescribed release cycle can be varied over a wide range dependent upon the prescribed relative location of abutment 46 and camming projection 48. This is shown by providing alternate positions for abutment 46, one such position being indicated by 46', with such positions being selectable from numerous radial locations on disc 40, at the proper radius for cooperation with abutment 26.

The locking mechanism 50 includes a pivot stud 52 affixed to support 12 which extends inwardly from the support towards the rotatable discs so as to be in close proximity with, and toe xtend over, the peripheral surface 21 of disc 20. A locking pawl 54, such as a cam ratchet, is pivotally mounted on pivot stud 52 and it is aligned with the peripheral surface 21 of disc 20 so that a tip 55 of locking pawl 54 mates with teeth 22 cut in peripheral surface 21. Pawl tip 55 is at the opposite end of locking pawl 54 from the pawls pilot point. A coil spring 56 is loosely coiled around pivot point stud 52, between support 12 and locking pawl 54, so as to normally bias tip 55 of the locking pawl into locking engagement with at least one tooth 22 on peripheral surface 21 of disc 20. One end 57 of coil spring 56 is retained in aforementioned aperture 18 of support 12, whereas the other end 58 of coil spring 57 extends across the top of locking pawl 54 between tip 55 and the pivot point of the locking pawl so as to provide the bias necessary to hold tip 55 in a tooth 22 and thereby normally lock disc 20 against rotation.

54 from locking engagement with the peripheral surface 21 of rotatable disc 20.

OPERATION The operation of release mechanism A of this invention is detailed with reference to both FIGURES l and 2, showing the release mechanism partially through a timing cycle. In the quiescent state of the release mechanism, shaft 10 and disc 40 are, together, spring *biased clockwise relative to disc 20 (see FIGURE 1) by torsion spring 30 so that abutment 46 is held against abutment 26, thus defining a predetermined starting point. In operation, shaft 10 is adapted to be driven counterclockwise by any suitable driving force, such as a motor operating through a suitable clutch mechanism (neither of which is shown), which permits shaft 10 to be returned clockwise back to the predetermined starting point by torsion spring 30 when the driving force to shaft 10 is removed.

Both in the quiescent state and the greater portion of the normal operating state, disc 20 is held locked, so as to not rotate, by tip 55 of locking pawl 54 under the bias of spring 56 with tip 55 sitting in a tooth 22 on peripheral surface 21 of disc 20. Therefore, abutments 26 and 46 serve to retain shaft 10 and disc 40 (which is attached to shaft 10) at the predetermined starting point with torsion spring 30 serving to bias both in the clockwise direc tion when shaft 10 is not being driven.

As shaft 10 is rotationally driven counterclockwise from the predetermined starting point, under operation, rotatable disc 20 is held locked by locking pawl 54. Rotatable disc 40 is likewise being rotated counterclockwise, being affixed to shaft 10 by locking screw 44. Therefore, as rotata'ble disc 40 is rotated counterclockwise, energy is stored in torsion spring 30 because of its mechanical coupling to both disc 40, now being rotated, and disc 20, which is still being held in a locked position by locking pawl 54.

When rotatable disc 40 has been rotated a predetermined amount (i.e., equal to one cycle), projecting camming surface 48 is driven against release pin 59, which is attached to a side surface of pivotable locking pawl 54 Release pin 59 is thereby .cammed upward against the bias of spring 56, pivoting locking pawl 54 counterclockwise sufficiently (see FIGURE 1) so as to release tip 55 from locking engagement with peripheral surface 21 of disc 20. When disc 20 is thus released, the energy previously stored within torsion Spring 30 causes loosely mounted disc 120 to be quickly rotated counterclockwise around shaft for the rotational distance defined when abutment 26 on disc 20 comes into physical contact with abutment 46 on disc 40, which disc is being driven at a rotational speed that is much less than the rotational speed that spring 30 imparts to disc 20. Shaft 10 and disc 40 continue to be driven counterclockwise, however, at the slower speed, carrying abutting disc 20 along for a short distance, and as soon as projecting camming surface 48 on disc 40 is rotated past release pin 59, locking pawl 54 is again permitted to be pivoted in the clockwise direction, under the bias of spring 56. Pivoting locking pawl 54 in the clockwise direction permits tip 55 of the locking pawl to again be in locking engagement with a prescribed tooth 22 on peripheral surface 21 to again lock disc 20 against rotation. Locking disc 20 once again against rotation, while continuing to rotate disc 40 counterclockwise, will cause energy to be stored once again in torsion spring 30. In this manner, every subsequent cycle starts from the predetermined starting point as long as there is power driving shaft 10 counterclockwise.

Should there be a loss of excitation for driving shaft 10, or a manual interruption in a timing cycle before the completion of such timing cycle, the operation of release mechanism A is identical, that is, a return of the release mechanism to the predetermined starting point.

Under either of the two above enumerated conditions, shaft 10 and rotatable disc 40 have been driven counterclockwise some distance less than that for a full cycle, storing energy in torsion spring 30, since disc 20 is held in a nonrotatable state by locking pawl 54 for any rotation of disc 40 that is less than a full cycle. Losing driving power to shaft 10 and to rotatable disc 40, under either of the two enumerated conditions, both the shaft and the disc are rotated clockwise under influence of the energy that has been stored in torsion spring 30.

Rotatable disc 40 will be rotated clockwise an amount determined, at one point, by where in the timing cycle the interruption occurred, and at the other point, when abutment 46 on face 47 of disc 40 comes in physical contact with abutment 26 on face 27 of disc 20. Since disc 20 is being held locked against rotation by locking pawl 54 at this time, the clockwise rotation of disc 40 will be ended when abutment 46 strikes abutment 26. As outlined previously, the predetermined starting point of the release mechanism is determined at this point, when abutment 46 is being held against abutment 26 under clockwise r0- tational force exerted by torsion spring 30, and when disc 20 is locked against rotation.

Therefore, release mechanism A has been shown to be reset to its predetermined starting point for a loss of excitation which provides the driving power to shaft 10, or for a manual interruption of a cycle before the completion thereof, just as release mechanism A was reset to its predetermined starting point for continuous cycling, or recycling, operations.

While a particular embodiment of this invention has been illustrated and described, it will be obvious to those skilled in the art that various structural modifications may be made in the preferred embodiment of the present invention as disclosed in the drawings without departing from the scope and spirit of the invention.

Iclaim:

1. A release mechanism comprising:

a shaft adapted to be rotated in opposing first and second directions;

first and second rotatable members located on said shaft in axially spaced relationship, said first member being fixed to said shaft for rotation therewith and said second member being loosely mounted on said shaft for rotation with respect to said shaft;

a coil spring loosely surrounding said shaft between said rotatable members, said coil spring having each of its opposing ends mechanically coupled to a different one of said rotatable members and being arranged so as to resiliently bias said second member for rotation in said first direction and to resiliently bias said first member for rotation in said second direction;

locking means for normally locking said second member against rotation in said first direction so that as said first member rotates in said first direction the energy stored in said coil spring increases to increasingly bias said second member in said first direction; an

lock release means carried by said first member for releasing said locking means after a predetermined angular rotation of said first member in said direction, whereupon the stored energy in said coil spring is released to drive said second member in said first direction.

2. A release mechanism as set forth in claim 1 including a rotation stop means for preventing more than 360 of respective angular movement between said rotatable members in either of said direction.

3. A release mechanism as set forth in claim 1 including a rotation stop means, said rotation stop means including a first and second stop member carried respectively by said first and second rotatable members, said stop members being located so as to be in interferring rotational paths for engaging each other to stop further rotational movement of at least one of said rotatable members relative to the other.

4. A release mechanism as set forth in claim 1 including a support, said coil spring being a torsion spring, and said locking means being mounted on said support in close proximity to both said first and second rotatable members, said locking means having a biasing means.

5. A release mechanism as set forth in claim 4 wherein said locking means includes a pivot stud attached to and extending from said support in the direction of said second rotatable member, a locking pawl pivotally mounted on said pivot stud and aligned with the peripheral surface of said second rotatable member, said locking pawl having a release pin protruding therefrom so as to extend away from said pivot stud and over the peripheral surface of said first rotatable member, and a second coil spring loosely mounted on said pivot stud between said support and said locking pawl so as to normally bias said locking pawl into locking engagement with the peripheral surface of said second rotatable member.

-6. A release mechanism as set forth in claim 5 wherein said second rotatable member is a disc having teeth cut in the peripheral surface thereof so as to form a ratchet, said locking pawl normally being biased into locking engagement with said ratchet by said second coil spring so as to normally lock said second rotatable member against rotation in said first direction when said shaft is being rotated, thereby to store energy in said coil sprin so as to impart rotational force to said first rotatable member in the event rotational driving power to said shaft is lost either because of a manual interruption, or because of a component malfunction, before the completion of a cycle.

7. A release mechanism as set forth in claim 6 wherein said first rotatable member is a disc carrying said lock release means on the peripheral surface thereof, said lock release means camming said release pin in a direction away from said peripheral surface of said first rotatable member at a predetermined point of rotation of said first rotatable member so that said locking pawl is operated against the bias of said second coil spring so as to unlock said second rotatable member and permit rotation thereof, whereby the stored biasing force imparted to said second rotatable member by said coil spring, during the times that said first rotatable member is being rotated in said first direction, quickly rotates said second rotatable member in said first direction faster than said first rotatable member is being rotated in said first direction.

8. A release mechanism as set forth in claim 7 wherein said rotation stop means includes a first and second stop member carried respectively by said first and second rotatable members, said stop means being located so as to References Cited UNITED STATES PATENTS 3,412,617 11/1968 Holzer 74-354 MILTON KAUFMAN, Primary Examiner US. (:1. XR 200-38

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