US3656370A

US3656370A - Cam assembly having multiple cams with integral cam positioning means thereon

Info

Publication number: US3656370A
Application number: US52019A
Authority: US
Inventors: Austin F Wilson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1970-07-02
Filing date: 1970-07-02
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18

Abstract

A cam assembly having a plurality of separate cam members mounted on a single drive shaft is provided with detent means that are operable to align the cam members in a predetermined angular displacement relative to one another, and maintain that displacement during operation of the assembly. The detent means on each cam member are substantially identical so that any given pair of cam members or a suitably mated replacement cam member may be operatively interlocked in the desired predetermined angularly displaced relationship without requiring further alignment procedures. In one embodiment of the invention, a unique cam-shift member is provided for readily changing the relative angular displacement between adjacent cam members without requiring these members to be removed from a drive mechanism on which they are mounted.

Description

United States Patent Wilson 1151 3,656,370 .1451 Apr. 18, 1972 [54] CAM ASSEMBLY HAVING MULTIPLE CAMS WITH INTEGRAL CAM POSITIONING MEANS THEREON [72] Inventor: Austin F. Wilson, Rochester, NH. [73] Assignee: General Electric Company 22 Filed: July 2, 1970 [21] Appl. No.: 52,019

52 Us. or. ..74/568 R p [51] Int. Cl ..Fl6h 54/04 [58} Field of Search ..74/568 R, 568 M, 568 T, 571 'M;

200/38 R, 38 BA, 38 C, 38.CA

[56] References Cited UNITED STATES PATENTS 2,468,974 5/1949 Hammer .74/568 x 2,473,417 6/1949 Essl ..74/568 3,221,117 11/1965 Simmons 74/568 X 3,499,347 3/1970 Pearson ..74/568 R27,04l 1/1971 Hotchkin ..74/568 X FOREIGN PATENTS OR APPLICATIONS 592,147 9/1947 I England ..74/568:

Primary Examiner-Milton Kaufman Assistant Examiner-F. D. Shoemaker Attorney-Francis X. Doyle, Vale P. Myles, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman [57] ABSTRACT A cam assembly having a plurality of separate cam members mounted on a single drive shaft is provided with detent means that are operable to align .the' cam members in a predetermined angular displacement relative to one another, and maintain that displacement during operation of the assembly.

The detent means on each cam member are substantially 8 Claims, 8 Drawing Figures PATENTEDAPR 18 1912 3, 656,370 SHEET 2 0. 2

0%]??? M19071, b y a .W

It is common practice in the prior art to use a plurality of cam members mounted on a single drive shaft or other suitable mounting means to operate as a control mechanism for selectively actuating a plurality of switches or other operating members in a predetermined sequence. In such devices, movably mounted cam follower members are positioned adjacent the respective cam members on the drive shaft in a manner such that rotation of the shaft causes the cam surfaces of the cam members to move the cam followers in a given preset pattern. In order to determine a desired sequence of operation of the cam follower-actuated operating members it is necessary to carefully orient the respective cam members with respect to one another and then lock them in this relative position. Prior to the present invention, such cam member orienting and locking functions were normally performed manually by individually adjusting each cam member to a given alignment with respect to the shaft and then locking the member to the shaft.

In addition to having the disadvantage of being very expensive to place in a desired operating relationship, such prior art multiple-cam member assemblies also tended to become unaligned during operation when one or more of the cam member locking means allowed its cam member to slip with respect to the operating shaft and the other cam members. Moreover, in these prior art assemblies no simplified cam alignment and locking means was provided for quickly adjusting the predetermined axial displacement between given pairs of cam members in order to effect a desired variation in the operating sequence of the operated members moved by the cam followers.

A primary object of the present invention is to provide an improved multiple-cam member assembly having cam orienting and positioning means that are more efficient to manufacture and operate than cam positioning means heretofore known.

Another object of the invention is to provide a mechanically simple and yet rugged cam orienting and positioning means for a plurality of interrelated cam members of a multiple-cam assembly, which are readily operable to align and maintain the respective cam members in a predetermined operating positron.

Yet another object of the invention is to provide a cam assembly having a plurality of cam members rotatably mounted on a drive shaft and provided with inter-locking detent means that are operable to orient and position the respective cam members in a predetermined desired relationship on the shaft by simply biasing the respective detent members into interlocking engagement with one another.

Still another object of the invention is to provide a simplified cam-shift member that is adapted to operate cooperatively with premolded detent means on a pair of cam members that are normally operable by a single drive mechanism on which they are maintained at a predetermined angular displacement with respect to one another. The cam-shift member is operable to easily vary the relative angular displacement between the two cam members without requiring them to be removed from the drive mechanism.

In one preferred embodiment of the invention, a cam assembly is provided with a plurality of rotatable cam members mounted on a single drive shaft. Each of the cam members is generally in the configuration of a disc having a cam-actuating surface on its circumference and having molded detent and projection means on each of its sides. Pursuant to the invention, the detent and projection means for each cam member are substantially identical and they are adapted to be moved into inter-locking engagement with respect to one another when the cam members are biased together, thereby to align and maintain the cam members in a predetermined angular displacement with respect to one another on the drive shaft. This predetermined angular displacement of the respective cam members allows them to operate associated cam followers that are riding on their respective cam surfaces through a desired sequence of operating patterns relative to one another. In one embodiment of the invention, a cam-shift member is provided for quickly and easily varying the relative angular displacement between the two cam members. This cam shift member can be inserted between the two cam members and snapped into operating position on the drive shaft without requiring either of the cam members to be removed from the drive shaft or from operating contact with their associated cam followers.

Additional objects and advantages of the invention will become apparent from the description that follows taken in conjunction with the attached drawings in which:

HG. l is a perspective view of a portion of a cam assembly constructed pursuant to the present invention and shown with respect to a pair of operating members in the form of electrical contacts that are actuated by movement of cam followers riding on cam members of the assembly.

FIG. 2 is a perspective view of a cam stop member or positioning means similar to a cam member positioning means shown in the assembly of FIG. 1 and interchangeable therewith.

FIG. 3a is a side elevation view of one of the cam members shown in the assembly of FIG. 1.

FIG. 3b is a top plan view of the cam member shown in FIG. 3a.

FIG. 3c is another side elevation view of the cam member shown in FIGS. 3a and 3b showing the side thereof opposite to the side illustrated in FIG. 3a.

FIG. 4a is a side elevation view of a cam-shift member constructed pursuant to the invention and adapted to be used in cooperation with the cam members illustrated in the assembly of FIG. 1 of the drawing to change the relative angular displacement between these members in a predetermined manner.

FIG. 4b is a top plan view of the cam-shift member illus trated in FIG. 40.

FIG. 40 is a side elevation view of the cam-shift member shown in FIGS. 40 and 4b and depicting the other side of this member.

Referring now to FIG. ll of the drawing, there is shown a cam assembly 1 comprising a plurality of separable cam members 2 and 3, which are generally disc-shaped in configuration and include respective cam surfaces 4 and 5 on the circumferential edges thereof. The cam surfaces 4 and 5 in this embodiment of the invention are in the form of a plurality of tooth-like projections, but other configurations may obviously be used, as will be apparent from the following description, without impairing the operability of the present invention. A pair of independently movable cam followers 6 and 7 are mounted in contact with the cam surfaces 4 and 5 respectively and are pivoted on a suitable rod 8, which in turn is supported by a pair of mounting brackets 9 and 10. The cam followers 6 and 7 each comprise a rod-like arm member 6' and 7', respectively, on which there is mounted a pair of movable electrical contacts 111 and 12. The contacts 11 and 112 are adapted to be closed respectively onto relatively fixed contacts 13 and 14, which are mounted on the support members 9 and 10. It should be understood that cam followers 6 and 7 are biased by gravity into contact with tooth-like surfaces t and 5 respectively; however, other biasing means, such as suitably mounted springs (not shown) may be used if desired. Alternatively, the arms 6' and '7' may be made of leaf springs that are clamped in a preset position with respect to mounting brackets 8 and 9, rather than being pivoted thereon, if such an arrangement for biasing the cam followers is desired. Also, it will be appreciated that suitable operating circuitry will normally be connected to the contacts 11-13 and 12-14; however, since such circuitry does not affect the invention disclosed herein, it is not illustrated in the embodiment of the invention shown in FIG. ll. Finally, although cam members 2 and 3 and mounting brackets 8 and 9 are shown in FIG. l in a spaced-apart mode, as will be apparent from the following description, these components will normally be mounted closely adjacent one another when assembly 1 is in operating position.

As can be seen in FIG. 1, a suitable mounting means in the form of a drive shaft is provided for supporting each of the cam members 2 and 3 in an operably movable position with respect to the cam followers 6 and 7. It should be understood that the cam members 6 and 7 each have an aperture through their center which is slightly larger than the diameter of the drive shaft 15 so that these cam members can slide easily with respect to the longitudinal axis of this drive shaft. A suitable drive means 16, which may be in the form of an electric motor or any other conventional drive mechanism, is coupled to the drive shaft 15 and operable to rotate the drive shaft in a clockwise direction as seen in FIG. 1. On the other end of drive shaft 15, a stop member 17 in the form of a disc is locked in position with respect to the shaft by a lock screw 18 mounted in a threaded aperture through a shank on the stop member 17. In addition, the stop member 17 comprises an elongated projection 19 on one side thereof which is adapted to engage the cam member 3 in a manner that will be described in more detail below, thereby to provide a driving coupling for the cam member 3.

Pursuant to the present invention, both of the cam members 2 and 3 are provided with a plurality of substantially identical, cooperatively inter-locking detent means that are mounted on the side surfaces thereof. On the cam member 2, these detent means comprise a pair of elongated, generally parallel projections-20 and 21 on one side of the cam member 2 and a single elongated projection 22 on the other side thereof. In like manner, the cam member 3 is provided with a pair of elongated generally parallel projections 23 and 24 on one side thereof and a single elongated projection 25 on its other side. Each of the single

elongated projections

22 and 25 are adapted to slide into inter-locking engagement with a cooperating pair of parallel projections on an adjacent cam member, for example, the projection 25 is adapted to slide into inter-locking engagement with the pair of

parallel projections

20 and 21 on the cam member 2. In fact, in accordance with the invention, when the cam members 2 and 3 are assembled in operating position they will be biased into abutting relationship so the projection 25 on cam member 3 is locked in position between the pair of

parallel projections

20 and 21 on cam member 2 thereby establishing a predetermined orientation and relative angular displacement between these two cam members. Further, in such an operating position, the cam member 3 is biased against the stop member 17 in a manner such that the projection 19 on this stop member is positioned in inter-locking engagement with the pair of parallel projections 23 and 24 on the cam member 3, and a slidably mounted locking means in the form of a releasable lock mechanism 26 on an annular ring having a set screw 27 mounted therein in conventional manner is moved into abutting contact with the inner surface of projection 22 on cam member 2 thereby to maintain the detent means in their respective inter-locked positions.

It can thus be seen that when the cam assembly 1 is arranged in its operating position with the respective cam members 2 and 3 biased toward the stop member 17, and interlocked therewith by the locking means 26, a predetermined angular displacement has been quickly and positively established between these respective cam members so that the cam followers 6 and 7 are actuated thereby in a predetermined sequence. Of course, it will also be apparent that the rate of operation of either of the pairs of contacts 11-13 or 12-14 can be varied by changing the number of tooth-like projections on either or both of the cam members 2 and 3. In addition, due to the novel arrangement of the present invention, it is possible to quickly and easily change the relative operating sequence of the two pairs of contacts 11-13 and 12-14. In this regard, it must be understood that in practicing the present invention the cam members 2 and 3 are preferably formed of thermal plastic material that is easily molded into precisely controllable configurations so that the generally disc-shaped cam members and their associated detents and projections are all integrally formed. Also, with any given cam assembly in which it may be desired to change the relative angular displacement between associated contact members, such as the members 2 and 3 of the assembly 1, a number of difierent cam members will be manufactured with various numbers of cam actuating tooth-like projections on the surface thereof, but each having substantially identical detent and projection means mounted on the respective sides thereof, so that these other cam members can be substituted for either or both of the cam members 2 and 3 by simply loosening set screw 18 in stop member 17 and sliding the stop member 17 and the cam members to be removed off of the shaft 15 so that the new cam members can be substituted in their place and the assembly reassembled. Moreover, as will be described in greater detail below, the present invention provides a unique means for varying the relative angular displacement between two cam members, such as the members 2 and 3 without requiring either of them to be removed from operating position.

Various modifications of the embodiment of the invention shown in FIG. 1 will be apparent to those skilled in the art. However, it is noted here that frequently in cam assemblies it is desirable to provide a plurality of cam-follower actuating members that are locked in a predetermined relative angular displacement with respect to one another, but which are otherwise free to rotate in an idling manner, i.e. without being directly subjected to a driving motion from a shaft, such as shaft 15. An embodiment of the invention, partially depicted in FIG. 2 of the drawing, is designed to afford such a mode of operating the invention as it is depicted in FIG. 1. As shown in FIG. 2, in which the same reference numerals are used to indicate parts identical to those used in FIG. 1, there is shown a portion of shaft 15 on which is mounted the stop member 17. In this fonn of the invention, the stop member 17 is not provided with a projection, such as the projection 19 illustrated in FIG. 1, therefore, when a cam member such as cam member 3 is biased against the stop member 17, it will simply be prevented from further axial movement along the shaft 15, but it will not be restricted from angular or rotary movement with respect to the shaft.

In order to more clearly describe the unique inter-locking detent means of the invention, a detailed illustration of one of the substantially identical cam members, in this case cam member 2, illustrated in FIG. 1, is shown in FIGS. 3a, 3b and 3c. Again, the same reference numerals are used in FIGS. 311-30 to designate component parts similar to those discussed above with reference to FIG. 1. Thus, on one side of the generally disc-shaped cam member 2 there is shown in FIG. 3a a pair of elongated generally

parallel projections

20 and 21 that define a channel-like detent 30 therebetween. On the other side of the cam member 2, as seen in FIG. 3c, a single elongated projection 22 is provided. According to the present invention, the width of the projection 22 is slightly smaller than the width of the channel-like detent 30 on the opposite side of the member 2, so that other cam members having identically formed detents and projections can be biased into inter-locking engagement with one another in the manner described above. As can perhaps be best seen in FIG. 3c, the longitudinal axis of the single projection 22 is angularly displaced by a predetermined angle, indicated by the arrow 31, with respect to the longitudinal axis of the channel-like detent 30. Thus, assuming a cam member 3 having substantially identically formed detent and projection means on the respective sides thereof is moved into inter-locking engagement with the detent or projection means on cam member 2, the two cam members would thereby be quickly and easily oriented so that their respective

single projections

22 and 25 would be displaced from one another by the predetermined angle indicated by the arrow 31. Of course, this angle is fixed permanently for any given set of molded cam members having detent means of the invention formed thereon. However, a

description will now be given of a further improvement of the present invention that provides a means for varying the relative angular displacement between cooperating cam members, such as the members 2 and 3.

In order to describe this modification of the present invention, reference is now made to FIGS. ta-4c of the drawing, in which there is shown a generally disc-shaped, thermal plastic, molded cam-shifting member constructed pursuant to the teaching of the invention. The cam-shift member 32 has a pair of generally

parallel projections

33 and 34 integrally formed on one side thereof and a single elongated projection 35 on the other side thereof. The

angular projections

33 and 34 define a channel-like detent 36 therebetween, which is sub- 1 stantially equal in width to the channel-like detent 30 in cam member 2. Also, the single projection 35 is substantially identical in width to the projection 22 on cam member 2. Thus, it will be understood that the cam-shift member is adapted to be operatively mounted between a pair of cam members such as the cam members 2 and 3 illustrated in the assembly 1 and interlocked in engagement with the detents and projections on these abutting cam members. The important unique feature of the cam-shift member 32 is that the relative angular displacement between the longitudinal axis of projection 35 and the

parallel projections

33 and 34 thereon, as shown by the arrow 37 in FIG. 4c is different (that is, either larger or smaller, as desired) than the angular displacement indicated by the arrow 31 in FIG. 3c. Thus, it will be apparent that when the cam-shift member is inter-locked in position between a pair of cam members such as the members 2 and 3, the relative angular displacement between these cam members is changed with respect to'the angular relationship maintained between them when they are directly inter-locked together by their associated detents and projections thereon. Accordingly, by simply placing the cam-shift member 32 in such an operating position, it is possible to quickly and easily change the angular displacement of two or more of the cam members on drive shaft 15. It should be understood that a plurality of cam-shift members each having different or the same relative angular displacements between their channel-lil e detent and oppositely disposed parallel projections can be provided for any given cam assembly such as the assembly 1 so that a number of different relative angular displacements may be easily provided at different times between the respective cam members 2 and 3 thereof. It should also be recognized that two or more of the cam-shift members, such as the shift member 32, may be used simultaneously to provide different combinations of relative angular displacement between the respective cam members 2 and 3.

A further important feature of the cam-shift member 32 is the provision of means defining a slot 38 from the periphery thereof to the annular aperture 39 at the center thereof. In the preferred embodiment of the invention, the thermal plastic material of which cam-shift member 32 is formed is sufficiently resilient to allow the side walls of the slot 38 to be resiliently biased slightly outward as it is forced over the shaft so that it can be quickly and easily snapped into position on the shaft 15 without requiring either of the cam members 2 or 3 to be removed from operating position. Thus, the walls of slot 38 comprise a resilient locking means that is operable to be biased into position to hold the cam-shift member 32 in operating position. Therefore, it is possible to change the relative angular displacement of the cam members 2 and 3 of the assembly 1 of the invention without requiring any portion of the assembly 1 to be dismantled to effect such a change.

Further advantages and modifications of the invention will become apparent to those skilled in the art and all such embodiments of the invention are intended to be encompassed within the scope of the following claims.

Iclaim:

l. A cam assembly comprising a plurality of separable cam members each of which include a cam surface for moving a cam follower, at least two independently movable cam followers, each of said cam followers being mounted adjacent to and in contact with one of said cam surfaces respectively to be moved thereby in response to movement of said surfaces, mounting means for supporting each of said cam members in an operably movable position with respect to said cam followers, a plurality of cooperatively inter-locking detent means respectively mounted on abutting surfaces of said cam members and operable when interlocked with one another to prevent relative movement between said cam members and to maintain the respective surfaces of said cam members in a predetermined relative angular position with respect to one another, said predetermined position being effective to establish a single given preselected angular displacement between the respective cam surfaces on said cam members, and locking means for maintaining said detent'means in their respective interlocked positions, said locking means being releasable thereby to facilitate relative movement of said cam members to at least one other predetermined relative position in which the detent means are effective when again interlocked to prevent relative movement of said cam members.

2. A cam assembly as defined in claim 1 wherein each of said cam members and the respective detent means thereon are formed from an integrally molded thermal plastic material, said cam members being generally disc-shaped with cam surfaces fonned on the circumference thereof, and said detent means comprising spaced-apart detents and projections in the side surfaces of said discs.

3. A cam assembly comprising a plurality of separable cam members each of which include a cam surface for moving a cam follower, at least two independently movable cam followers each of said cam followers being mounted adjacent and in contact with one of said cam surfaces respectively to be moved thereby in response to movement of said surfaces, mounting means for supporting each of said cam members in an operably movable position with respect to said cam followers, a plurality of cooperatively inter-locking detent means respectively mounted on abutting surfaces of said cam members and operable when interlocked with one another to prevent relative movement between said cam members and thereby maintain said cam members in a predetermined relative position with respect to one another, and locking means for maintaining said detent means in their respective interlocked positions, said locking means being releasable thereby to facilitate relative movement of said cam members to at least one other predetermined relative position in which the detent means are effective when again interlocked to prevent relative movement of said cam members, the configuration of the detents and projections on each of said cam members being substantially identical thereby to enable given cam members to be interchanged with respect to one another and still afford a cooperatively interlocking relationship therebetween, each of said cam members having a pair of elongated generally parallel projections on one side thereof with a detent channel therebetween and having a single elongated projection on the other side thereof, each of said single elongated projections being adapted to slide into inter-locking engagement with a pair of parallel projections on an adjacent cam member.

4. A cam assembly as defined in claim 3 wherein the iongitudinal axis of the single elongated projection on one side of a cam member is angularly displaced with respect to the axis of said cam member in relation to the longitudinal axes of the pair of elongated generally parallel projections on the other side thereof.

5. A cam assembly as defined in claim 2 including a camshift member operatively mounted between a pair of said cam members, said cam-shift member having projections on opposite sides thereof that are adapted to fit in inter-locking engagement with the detents and projections on the cam members abutting it, the projections on opposite sides of said camshift member being mounted in a predetermined relatively angular displaced position with respect to one another, thereby to cause a relative angular displacement between a pair of cam members with which it is inter-locked with respect to the angular relationship maintained between said pair of cam memsaid mounting means.

8. A cam assembly as defined in claim 7 wherein said resilient locking means comprises a generally disc-shaped resilient member having means defining a radial slot therein from the periphery to the center thereof, said slot being adapted to be resiliently slipped onto the mounting means for said cam members thereby to hold the cam-shift member in operating position.

Claims

1. A cam assembly comprising a plurality of separable cam members each of which include a cam surface for moving a cam follower, at least two independently movable cam followers, each of said cam followers being mounted adjacent to and in contact with one of said cam surfaces respectively to be moved thereby in response to movement of said surfaces, mounting means for supporting each of said cam members in an operably movable position with respect to said cam followers, a plurality of cooperatively inter-locking detent means respectively mounted on abutting surfaces of said cam members and operable when interlocked with one another to prevent relative movement between said cam members and to maintain the respective surfaces of said cam members in a predetermined relative angular position with respect to one another, said predetermined position being effective to establish a single given preselected angular displacement between the respective cam surfaces on said cam members, and locking means for maintaining said detent means in their respective interlocked positions, said locking means being releasable thereby to facilitate relative movement of said cam members to at least one other predetermined relative position in which the detent means are effective when again interlocked to prevent relative movement of said cam members.

2. A cam assembly as defined in claim 1 wherein each of said cam members and the respective detent means thereon are formed from an integrally molded thermal plastic material, said cam members being generally disc-shaped with cam surfaces formed on the circumference thereof, and said detent means comprising spaced-apart detents and projections in the side surfaces of said discs.

3. A cam assembly comprising a plurality of separable cam members eAch of which include a cam surface for moving a cam follower, at least two independently movable cam followers each of said cam followers being mounted adjacent and in contact with one of said cam surfaces respectively to be moved thereby in response to movement of said surfaces, mounting means for supporting each of said cam members in an operably movable position with respect to said cam followers, a plurality of cooperatively inter-locking detent means respectively mounted on abutting surfaces of said cam members and operable when interlocked with one another to prevent relative movement between said cam members and thereby maintain said cam members in a predetermined relative position with respect to one another, and locking means for maintaining said detent means in their respective interlocked positions, said locking means being releasable thereby to facilitate relative movement of said cam members to at least one other predetermined relative position in which the detent means are effective when again interlocked to prevent relative movement of said cam members, the configuration of the detents and projections on each of said cam members being substantially identical thereby to enable given cam members to be interchanged with respect to one another and still afford a cooperatively inter-locking relationship therebetween, each of said cam members having a pair of elongated generally parallel projections on one side thereof with a detent channel therebetween and having a single elongated projection on the other side thereof, each of said single elongated projections being adapted to slide into inter-locking engagement with a pair of parallel projections on an adjacent cam member.

4. A cam assembly as defined in claim 3 wherein the longitudinal axis of the single elongated projection on one side of a cam member is angularly displaced with respect to the axis of said cam member in relation to the longitudinal axes of the pair of elongated generally parallel projections on the other side thereof.

5. A cam assembly as defined in claim 2 including a cam-shift member operatively mounted between a pair of said cam members, said cam-shift member having projections on opposite sides thereof that are adapted to fit in inter-locking engagement with the detents and projections on the cam members abutting it, the projections on opposite sides of said cam-shift member being mounted in a predetermined relatively angular displaced position with respect to one another, thereby to cause a relative angular displacement between a pair of cam members with which it is inter-locked with respect to the angular relationship maintained between said pair of cam members when they are directly interlocked together by the detents and projections thereon.

6. A cam assembly as defined in claim 5 wherein said cam-shift member includes a resilient snap-action locking means for releasably holding it in operating position between said pair of cam members.

7. A cam assembly as defined in claim 6 wherein said resilient locking means is operable to enable said cam-shift member to be placed in operating position between said pair of cam members without requiring the removal of them from said mounting means.