US3885470A - Camming system including a flexible cam of adjustable peripheral length - Google Patents

Abstract

A camming system which includes a cam carrier supporting a flexible cam of selectively adjustable peripheral length. The carrier and a sensor for sensing the cam when it is proximate the sensor are mounted for motion relative to each other along a predetermined path. A guide track on the carrier supports the cam with at least a portion of the cam exposed to and facing toward the sensor to be sensed thereby. A hub mounted on the carrier is attached to one end of the cam and may be rotated to wind and unwind the cam so that it extends for a selectively variable peripheral length along the guide track.

Description

[451 May 27, 1975 1' CAMMING SYSTEM INCLUDING A FLEXIBLE CAM OF ADJUSTABLE PERIPHERAL LENGTH [75] Inventors: Robert B. Costa, Covina; Edward M. Troup, Mt. Baldy, both of Calif.

[73] Assignee: Clemar Manufacturing Corporation,

Glendora, Calif.

[221 Filed: Nov. 8, 1973 [21] Appl. No.: 413,885

[52] U.S. Cl 74/568 R; 74/568 FS; 74/568 T; 200/38 CA [51] Int. Cl. Fl6h 53/00 [58] Field of Search 74/568 FS, 568 M, 568 T, 74/568 R; 200/38 CA [56] References Cited Condon et al. 74/568 R X Cole 74/568 M Primary Examiner-Samuel Scott Assistant ExaminerF. D. Shoemaker Attorney, Agent, or F irm-Fulwider, Patton, Rieber, Lee, & Utecht [57] ABSTRACT A camming system which includes a cam carrier supporting a flexible cam of selectively adjustable peripheral length. The carrier and a sensor for sensing the cam when it is proximate the sensor are mounted for motion relative to each other along a predetermined path. A guide track on the carrier supportsthe cam with at least a portion of the cam exposed to and facing toward the sensor to be sensed thereby: A hub mounted on the carrier is attached to one end of the cam and may be rotated to wind and unwind the cam so that it extends for a selectively variable peripheral length along the guide track.

17 Claims, 8 Drawing Figures CAMMING SYSTEM INCLUDING A FLEXIBLE CAM OF ADJUSTABLE PERIPHERAL LENGTH BACKGROUND OF THE INVENTION This invention relates to a cam assembly incorporating a flexible cam, the peripheral length of which may be selectively adjusted to vary the range of cam operation.

In performing timing or positioning functions, it is well known to utilize systems involving mechanical cams. Such systems typically incorporate a cam carrier which supports the cam for motion in relation to a sensor which senses the cam. The sensor provides an output which varies dependent on whether the cam is proximate to the sensor or has moved beyond it. In applications where the control function performed by the cam may need to be changed from time to time, it is known to provide for adjustment of the range of cam operation relative to the carrier, for example, by positioning of clips at selectively variable spacings around the periphery of the carrier or by attaching projecting portions on the carrier.

One prior cam assembly disclosed in U.S. Pat. No.

3,678,780, issued July 25, 1972 to Ivor Ponting, discloses a cam assembly including a cam carrier in the form of a serrated cylindrical body provided with bosses at its opposite axial ends upon which are rotationally mounted two segmental cams provided with inwardly projecting resilient portions which engage the body serrations to act as detents. Two adjacent shoulders on the cams are spaced apart to define an in-dwell region of reduced peripheral radius while the remaining region of the two cams overlap to provide an outdwell region of greater radius extending around the remainder of the periphery. The in-dwell region may be adjusted in its length relative to the total periphery by turning the cam segments relative to. each other on the carrier body.

Although satisfactory for its intended purpose, suc a prior cam assembly may have some disadvantages. For example, such a cam assembly provides for only a single adjustable control function on the one cam carrier, whereas, for certain applications, it may be essential to mount a plurality of separate, individually adjustable cams of differing peripheral length on a single cam carrier.

In addition, in such a prior cam assembly, the indwel] region is necessarily of a curved configuration centered on the radius of rotation of the cam carrier, whereas, under certain circumstances, it may be desirable to have an adjustable cam which is straight or has a curvature greater or less than the radius of curvature about the axis of movement of the cam carrier. Additionally, such a prior cam assembly which utilizes cam segments mounted at opposite axial ends of the carrier may cause chanting of a mechanical cam follower because the cam segments are laterally separated due to their mounting at opposite ends of the cam carrier.

SUMMARY OF THE INVENTION plurality of the adjustable flexible, cams may be mounted on a single carrier to provide a sequence of control functions of differing duration during a single cycle of movement of the cam carrier relative to the sensor. Each adjustable cam may be separately adjusted to vary its peripheral length relative to the carrier without requiring any change in the adjustment of the peripheral length of the other cams on the carrier. The cam assembly of the invention therefore enables a single cam carrier to support a plurality of separately adjustable cams for selective and individual variation of control functions.

In another aspect of the invention, each cam, when it is used in association with a mechanical cam follower, can be positioned to maintain a uniform centered relation of the follower on the cam follower during the complete path of travel of the cam past the follower. With such an arrangement there is no tendency to impose side or tilting forces on the cam follower which might introduce error into the operation of the associated sensing equipment.

In more detail, the carrier is provided with an elongate guide track. The cam comprises an elongate flexible wall having opposite longitudinal edges. The guide track slidably engages at least one of the edges to support the wall relative to the carrier extending along the guide track with at least a portion of the wall surface to and facing towards the sensor to be sensed thereby. A hub is fixedly secured to one longitudinal end of the flexible wall and is mounted on the carrier for rotation about an axis parallel to the wall surface. By rotation of the hub the wall may be wound and unwound along the guide track to vary the peripheral extent to which it is exposed to the sensor.

The sensor may sense the cam in a variety of ways including mechanical contact, photoelectric sensing, fluid pressure, magnetic sensing, and detection of radioactivity.

The hub and its connection to the carrier incorporate resilient detent portions so that once the hub has been turned to 'set the cam length at a preselected value, the detents maintain the setting during operation.

The foregoing, and other advantages and features of the invention are described more fully in the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS A camming system according to certain preferred embodiments of the invention is illustrated in the accompanying drawings in which:

FIG. 1 shows a camming system including a rotary cam carrier which carries a plurality of cam assemblies, each contructed according to the preferred embodiment of the invention, past a sensor;

FIG. 2 is a cross-sectional side view on an enlarged scale through a hub portion of one of the cam assemblies shown in FIG. 1;

FIG. 3 is a perspective view of an adjustable cam forming a part of the assembly shown in FIG. 2',

FIG. 4 is a top view of the adjustable cam shown in FIG. 3;

FIG. 5 is a cross-sectional view of a portion of the cam assembly shown in FIG. 2 taken along the line 5-5 therein, illustrating certain detent portions thereof in an engaged condition;

FIG. 6 is a further view of the detent portions shown in FIG. 5 when a torque is applied to force the detent portions apart during adjustment of the cam assembly; and

FIGS. 7 and 8 show a second embodiment of the invention wherein the cam assembly is mounted on a stationary carrier and a sensor is moved in a straight linear direction past the adjustable cam assembly.

DETAILED DESCRIPTION Referring to FIG. 1 of the drawings, a plurality of adjustable cam assemblies 2, each constructed according to the preferred embodiment of the invention, are shown mounted on a rotary cam carrier 4. The cam carrier, which rotates in an anticlockwise direction, carries the adjustable cam assemblies 2 consecutively past a sensor 6 which is activated and deactivated, thereby performing control functions.

The rotary cam carrier 4 can be, for example, a station timer of the type forming part of the Timing Unit For Connecting Power Sequentially To A Plurality Of Stations" disclosed in the patent application of Norman A. Morgan, filed concurrently with the present application and assigned to the same assignee. The timing system disclosed in that application is utilized to control the operation of a sprinkler system having a number of sprinklers which are to be actuated in cycles of operation in which each sprinkler is operated sequentially during each cycle for a period which is separately and individually adjustable for each sprinkler. However, it is to be realized that the adjustable cam of the present invention is in no way confined to use in timing systems. For example, instead of operating a cam follower to perform a timing control function, the adjustable cams 2 could be utilized to perform a positioning function such as displacing a valve actuator controlling flow of liquid through a controlled system. Moreover, it is not necessary that the adjustable cams be mounted on a rotary cam carrier. Additionally, it would be possible to utilize the adjustable cam assembly of the invention in a system wherein the cam remains stationary while a plurality of sensors moves sequentially past the cam.

However, for ease of description, the cam assembly according to the first embodiment of the invention, will be described primarily with reference to use in a system involving the rotary cam carrier 4 utilized for controlling a sensor 6 to perform functions. In the embodiment shown in FIG. 1 the sensor is an electrical switch 7 having a pivoted finger 8 extending in a direction generally tangentially to the cam carrier 4. At its free end the finger 8 includes a radially extending portion which is biased in a direction radially towards the center of rotation of the cam carrier by a spring biased plunger 12 controlling the on-off operation of the switch 7.

Each adjustable cam assembly 2 includes an adjustable cam 14 (FIG. 3) formed of resiliently flexible, sheet-like material having a generally rectangular, elongate configuration when in an extended condition. The cam includes opposed longitudinal edges 16 and 18. In the preferred embodiment, the cam is a generally rectangular wall of sheet material. The cam can alternatively be of other configurations such as, for example, a cord-like configuration having a circular or triangular cross-section.

The cam carrier 4 is of greater thickness than the width of the cam 14 and has an annular opening 20 (FIG. 2) extending completely about its peripheral edge into which the projection at the end of the finger 8 projects. The cam 14 extends laterally across the opening 20 and is supported therein by aligned, rectangular cross-section guide slots 22 and 24 extending into the body of the carrier. The guide slots 22 and 24 constitute an elongate guide track having a curvature centered about the axis of rotation of the cam carrier so they support the wall 14 at a corresponding curvature. In this position the cam has one of its faces exposed to and facing outwardly towards the finger of the sensor.

When the end of the sensor 8 is riding on the surface of the cam 14 it is in a raised condition and when the cam passes beyond the end of the finger 8, the finger moves radially inward to a depressed condition through a distance at least equal to the thickness of the cam 14. The sensitivity of the switch contacts is such as to enable this range of movement to control the opening and closing of the switch 7.

To enable selective adjustment of the peripheral extent to which the cam 14 extends along the guide tracks 22 and 24, the leading end of the cam (in the direction of motion of the cam carrier) is fixedly secured to a hollow, circular hub 26 (FIG. 3). The hub 26 includes a plurality of internally serrated axially extending fingers 28 which engage the correspondingly serrated external face of a stationary axle 29 (FIG. 2) fixedly secured to the carrier supporting the hub for rotation about an axis parallel to the cam surface. The hub 26 also includes an annular skirt 30 to which the leading end of the cam is connected in tangential relation. The skirt 30 is concentrically spaced about and connected to the fingers 28 by an annular shoulder portion 32. The skirt is rotatably received within a bore 34 in the cam carrier which assists in supporting the hub for rotation. The bore 34 has closed axial ends axially abutting the shoulder 32 and the free opposite axial end of the hub 26 to center the latter axially in the cam carrier. Extending concentrically from the hub 30 in an opposite direction from the fingers 28 is an adjustment knob 36 projecting through an opening 38 in the cam carrier. For ease of assembly, the rotary cam carrier 4 is formed from two separate discs 14a and 14b secured together in abutting concentric relation. The discs are initially separated to enable the hub 26 to be mounted in position in the bores 34.

By turning the knob 36 manually, the cam 14 can be wound onto and off the hub 26 to vary the peripheral extent to which the cam extends along the guide tracks. It will be understood that the bore 34 has to be sufficiently large to accommodate the cam as it is wound onto the hub. In this connection, the skirt 30 includes a depressed region 40 adjacent the point of connection thereto of the wall 14 to enable the cam to collapse inwardly against the hub. In addition, the further peripheral portions of the hub 26 extending away from the depressed region 40 may also be reduced somewhat out of circularity to accommodate 'the collapsing thereagainst of the cam within the bore 34 as the cam is wound onto the hub.

The engagement of the serrated fingers 28 with the corresponding serrations on the axle 29 (FIGS. 5 and 6) has a detent action whereby, once the cam has been adjusted to a particular length, the engaging serrations yieldably resist displacement of the hub relative to the axle so that the cam maintains its preselected position. Application of torque above a predetermined value causes the fingers 28 to be moved apart so that the hub can free itself for rotation. To assist in maintaining engagement between the serrations on the fingers 28 and the axle 29, a resilient metal split-ring 42 mounted in a groove embracing the lower'ends of the fingers 28 is provided. 1

In operation, as one of the cam assemblies moves towards the sensor, the curved portion of the cam 14 wound about the hub (or if the cam is fully extended, the hub itself) moves into contact with the projection at the free end of the finger 8. As the carrier 4 continues to rotate, the curved surface guides the finger onto the main part of the cam 14, thereby raising the finger 8 and operating the switch 7 to one of its open and closed conditions. During continued rotation, as long as the finger remains in contact with the cam 14, the switch 7 remains in the same condition. When the trailing end of the cam 14 moves past the end of the finger 8, the finger pivots downwardly through a radial distance at least equal to the thickness of the cam 14, thereby causing the switch 7 to operate in the other of its open and closed conditions. The change in condition of the switch 7 may be used to perform a control function in. any well-known manner. The switch 7 will remain in the second condition until the following one of the cam assemblies 2 reaches the fingerof the sensor and the switch 7 is again restored to the first condition. The switch sensor 6 will then remain in the first condition for a further period dependent upon the selected peripheral extent of the cam 14 as preselected by rotation of the associated knob 36.

It will be appreciated that with the foregoing arrange ment, the periods for which the sensor operates in its first condition can be selectively and individually adjusted for each of the different cam assembles. Thus, the structure of the present invention enables a large number of separately adjustable cams to be mounted on a single cam carrier. All that is necessary is that the cam carrier be made of sufficiently large radius to accommodate the desired number of individually adjustable cam assemblies. In addition, as contrasted with a system based on spacing between clips, there is no aggregation or cumulation of periods which would require adjustment of each of the downstream positions as is required on some prior devices.

To facilitate visual adjustment of each cam, a calibrated scale 50 (FIG. 1) extends adjacent each guide track. A pointer 52, comprising a projecting member secured to the free, rear end of the cam 14 (in the direction of rotation), registers with the calibrated scale 50. The movement of the pointer 52 against the scale 50 thus provides an easy visual reference for adjustment. Where the cam assembly is being used for a tim ing function, the maximum time that would be taken to traverse between the extreme position of adjustment of the cam at a particular rate of rotation of the cam carrier can be determined and the scale 50 can be calibrated directly in increments of time.

In the preferred embodiment, the cam 14, hub 26, fingers 28, knob 36 and pointer 52 are molded as an integral structure from a suitable plastic. The mechanical properties of the plastic must be such that the cam 14 can bend sufficiently to follow the guide tracks and to wind about the hub, yet it should not be so compliant that it will be unable to resist deformation at the end of the spring biased finger 8 on the sensor. Suitable plasticsfrom which the wall 14 may be fabricated include polypropylene, polyethylene, .copolymers of propylene and ethylene, and certain fluorocarbon polymers, including polytetrafluorethylene "(PTFE), commonly known as Teflon. To assist in maintaining sufficient rigidity of the wall 14, the guide tracks 22 and 24 extend a significant distance inwardlyfrom the edges of the cam to provide support thereof. In addition, at the free, trailing end of the wall 14, it is provided on its opposite side from the sensor with a semicircular strengthening rib 53.

Although the invention has thus far been described with reference to a mechanical sensor, an adjustable cam assembly according to the invention may be used with sensors of other types. Thus, the cam 14 may be used in conjunction with a fluid pressure sensor whereby a jet of fluid is directed against the cam surface through a nozzle so that as the cam passes beyond the nozzle there is a change in pressure which can be used to provide the control function. Photoelectric sensing may be employed utilizing a light sensor and a photo-detector wherein breaking of a light path causes a change in signal condition or, alternatively, utilizing a refiectively coated cam to provide a reflective. light path between the source and detector which isinterrupted. As a further modification, a magnetically coated cam could be used in conjunction with a megnetically responsive sensor. In a further. variation, the cam material could be impregnated with a low level of radioactivity and the sensor could incorporate ascintillation counter or like device to respond to the passage of the cam past the sensor. Such alternative sensing devices are not intended to be exhaustive and other wellknown cam sensing means may be employed with ,the adjustable cams constructed in accordance with the invention. j

Nor is it necessary that the cam beemployedsolely in a camming system where apluralityof the cams'are moved successively past a single sensor. For example, FIGS. 7 and 8 show a further embodiment of theinvention in which a plurality of sensors,.carri ed by a conveyor belt 60,-pass sequentially past a single one of the adjustable cams. For example, such a system could be used in conjunction with objects carriedby the belt to control spraying of each object at a station adjacent the cam for a predetermined length of time dependent on the selected peripheral length of the cam.

Summarizing, a cam assembly according to the present invention has the advantage thata large number of the cam assemblies can be mounted on a single cam carrier while permitting each cam assembly to be separately adjusted withoutrequiring any change in the adjustment of any of the remaining cam assemblies. Additionally, each cam assembly can be adjusted without requiring the use of screw drivers, special setting tools, adhesives or other hard to adjust expedients. More over, each cam assembly is mounted in a protected condition within the carrier so that is is not vulnerable to being knocked off in the same manner that clips and other projections may be. The provision of a calibrated scale and indicating pointer enables the cam assemblies to be adjusted by persons of average skill without;requiring special competence or the .performance ,of mental calculations prior to adjustment of cam position. It is also advantageous that the cam assembly can readily be molded from inexpensive plastic materials thereby providing a structure which lends itself to low cost production and ease of fabrication.

Although the invention has been described with reference to certain preferred embodiments, it will be understood by thoseskilled in the art that many deletions, additions, substitutions, modifications, I and other changes may be made which will fall within the spirit of the invention disclosed and claimed herein.

We claim:

1. For use in a camming system including a sensor and a cam carrier mounted for motion relative to each other along a predetermined path of motion, an adjustable cam assembly comprising:

an elongate guide track on the carrier;

an elongate flexible cam movable along said guide track, said cam having opposite longitudinal ends, said guide track supporing said cam with at least a longitudinally extending portion of said cam exposed to and facing towards the sensor to be sensed thereby when proximate to the sensor.

a hub fixedly secured to one longitudinal end of said cam; and

mounting means for rotatably mounting said hub on the carrier to enable said cam to be selectively would onto and off said hub to vary the longitudinal exent of the portion of said cam exposed to the sensor.

2. An adjustable cam assembly as defined in claim 1, wherein said hub has a central bore concentric with the axis of rotation of said hub and wherein said mounting means comprises a stationary axle fixedly secured to the carrier extending concentrically into said bore to support said hub for rotation.

3. An adjustable cam assembly as defined in claim 2,

further including:

detent means for yieldably resisting rotational movement between said hub and said axle.

4. An adjustable cam assembly as defined in claim 3,

wherein said detent means includes:

a plurality of serrations on said axle;

a plurality of fingers connected to said hub extending in overlapping contact with said axle spaced around the periphery thereof to support said hub for rotation on said axle, said fingers having serrations biased into engagement with the serrations on said axle, said fingers flexing radially outwardly to cause said serrations to move out of engagement to enable turning of said hub when torque in excess of a predetermined value is applied thereto.

5. An adjustable cam assembly as defined in claim 4,

further including:

a resilient split ring connected with said fingers for resiliently biasing said fingers against said axle.

6. An adjustable cam assembly as defined in claim 2,

' further including:

an adjustment member projecting from said hub at an end thereof remote from said carrier, said adjustment member adapted to be grasped to turn said I: .hub relative to said carrier for adjustment of the :length of said portion of said cam exposed to the sensor. t 7. An adjustable cam assembly as defined in claim 1,

.wherein the sensor remains stationary and said cam is carried past the sensor by the cam carrier along the 9. A camming system comprising:

a sensor;

a cam carrier, said cam carrier and said sensor being connected with each other for relative motion therebetween along a predetermined path of motion;

an elongate guide track on the carrier;

an elongate flexible cam movable along said guide track, said cam having opposite longitudinal ends, said guide track supporting said cam with at least a longitudinal portion of said cam exposed to and facing towards the sensor to be sensed thereby;

a hub fixedly secured to one of said longitudinal ends of said cam; and

mounting means for rotatably mounting said hub on said carrier to enable said cam to be selectively wound onto and off said hub to decrease and increase the longitudinal extent of the portion of said cam exposed to said sensor.

10. A camming system as defined in claim 9, wherein said sensor senses said cam by mechanical contact.

11. A camming system as defined in claim 9, wherein said sensor senses said cam photoelectrically.

12. A camming system as defined in claim 9, wherein said sensor senses said cam by fluid pressure.

13. A camming system as defined in claim 9, wherein said sensor senses said cam magnetically.

14. A camming system as defined in claim 9, wherein said sensor senses said cam by detection of radioactivity.

15. A camming system, comprising: a frame; a rotary cam carrier mounted on said frame for rotation thereon, said cam carrier being divided along its periphery into a plurality of sectors; a plurality of cam assemblies each connected with one of said sectors, each said cam assembly includ- 1n an elongate guide track on said carrier. an elongate flexible cam movable along said guide track, said guide track supporting said cam with at least a peripherally extending, exposed portion of said cam facing outwardly from said carrier,

varying means for selectively varying the peripheral extent of said exposed portion of said cam; and

a sensor mounted on said frame for sensing the exposed portion of each said cam as each of said cam assemblies moves past said sensor during rotation of said cam carrier.

16. A camming system as defined in claim 15,

wherein for each said cam assembly:

each said cam has opposite longitudinal ends spaced peripherally of said carrier;

and wherein each said varying means includes:

a hub fixedly secured to one of said longitudinal ends of the associated one of said cams; and

mounting means for rotatably mounting said hub on said carrier to enable the associated said cam to be selectively wound onto and off said hub to decrease and increase the longitudinal extent of the outwardly facing exposed portion thereof, respectively.

17. A camming system as defined in claim 16, wherein said sensor includes a finger biased downwardly into the path of travel of said cams successively past said sensor, each of said hubs being positioned at the leading end of the associated said cam in the direction of movement thereof past said sensor and being curved to guide and raise said finger onto said cam as said cam passes beneath said sensor.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORREQTION PATENTNO.: 3,885,470

ATED D May 27, 1975 |NVENTOR(S) Robert Costa et a1.

It is certified that error appears in the ab0ve-identified patent and that said Letters Patent are hereby corrected as shown below:

Colume 1, line 57, "chanting" should be canting Colume 2 line 25, after "surface" the word exposed i is omitted.

Colume 5, line 52, "position" should be positions Colume 6, line 3, "thereof" should be therefor Colume 6, line 53, after "that", "is" should be is Colume 7, line 11, "supporing" should be supporting Signed and Erealed this fourteenth D 3.) 0 f October 1 9 75 [SEAL] Attest:

RUTH C. MrtSON C. MARSHALL DANN Arresting Officer Commissioner of Patents and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,885,470

DATED May 27, 1975 INVENTOIKS) I b t B. C -ta e't al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Colume 1, line 57, "chanting" should be canting Colume 2, line 25, after "surface" the word exposed is omitted.

Colume 5, line 52, "position" should be positions Colume 6, line 3, "thereof" should be therefor Colume 6, line 53, after "that", "is" should be is Colume 7, line 11, "supporing" should be supporting Signed and Sealed this fourteenth D ay of October 1975 [SEAL] A ttest:

RUTH C. MRSON p C. MARSHALL DANN Arresting Officer Commissioner ufParents and Trademarks

Claims (17)

1. For use in a camming system including a sensor and a cam carrier mounted for motion relative to each other along a predetermined path of motion, an adjustable cam assembly comprising: an elongate guide track on the carrier; an elongate flexible cam movable along said guide track, said cam having opposite longitudinal ends, said guide track supporing said cam with at least a longitudinally extending portion of said cam exposed to and facing towards the sensor to be sensed thereby when proximate to the sensor. a hub fixedly secured to one longitudinal end of said cam; and mounting means for rotatably mounting said hub on the carrier to enable said cam to be selectively would onto and off said hub to vary the longitudinal exent of the portion of said cam exposed to the sensor.

2. An adjustable cam assembly as defined in claim 1, wherein said hub has a central bore concentric with the axis of rotation of said hub and wherein said mounting means comprises a stationary axle fixedly secured to the carrier extending concentrically into said bore to support said hub for rotation.

3. An adjustable cam assembly as defined in claim 2, further including: detent means for yieldably resisting rotational movement between said hub and said axle.

4. An adjustable cam assembly as defined in claim 3, wherein said detent means includes: a pluraality of serrations on said axle; a plurality of fingers connected to said hub extending in overlapping contact with said axle spaced around the periphery thereof to support said hub for rotation on said axle, said fingers having serrations biased into engagement with the serrations on said axle, said fingers flexing radially outwardly to cause said serrations to move out of engagement to enable turning of said hub when torque in excess of a predetermined value is applied thereto.

5. An adjustable cam assembly as defined in claim 4, further including: a resilient split ring connected with said fingers for resiliently biasing said fingers against said axle.

6. An adjustable cam assembly as defined in claim 2, further including: an adjustment member projecting from said hub at an end thereof remote from said carrier, said adjustment member adapted to be grasped to turn said hub relative to said carrier for adjustment of the length of said portion of said cam exposed to the sensor.

7. An adjustable cam assembly as defined in claim 1, wherein the sensor remains stationary and said cam is carried past the sensor by the cam carrier along the predetermined path of motion.

8. An adjustable cam assembly as defined in claim 1, wherein a calibrated scale is provided on the carrier extending adjacent said guide track and wherein said cam at the opposite longitudinal end thereof is provided with a pointer aligned with said graduated scale for indicating the position of said opposite end of said cam relative to said scale during winding and unwinding of said cam about said hub.

9. A camming system comprising: a sensor; a cam carrier, said cam carrier and said sensor being connected with each other for relative motion therebetween along a predetermined path of motion; an elongate guide track on the carrier; an elongate flexible cam movable along said guide track, said cam having opposite longitudinal ends, said guide track supporting said cam with at least a longitudinal portion of said cam exposed to and facing towards the sensor to be sensed thereby; a hub fixedly secured to one of said longitudinal ends of said cam; and mounting means for rotatably mounting said hub on said carrier to enable said cam to be selectively wound onto and off said hub to decrease and increase the longitudinal extent of the portion of said cam exposed to said sensor.

10. A camming system as defined in claim 9, wherein said sensor senses said cam by mechanical contact.

11. A camming system as defined in claim 9, wherein said sensor senses said cam photoelectrically.

12. A camming system as defined in claim 9, wherein said sensor senses said cam by fluid pressure.

13. A camming system as defined in claim 9, wherein said sensor senses said cam magnetically.

14. A camming system as defined in claim 9, wherein said sensor senses said cam by detection of radioactivity.

15. A camming system, comprising: a frame; a rotary cam carrier mounted on said frame for rotation thereon, said cam carrier being divided along its periphery into a plurality of sectors; a plurality of cam assemblies each connected with one of said sectors, each said cam assembly including, an elongate guide track on said carrier. an elongate flexible cam movable along said guide track, said guide track supporting said cam with at least a peripherally extending, exposed portion of said cam facing outwardly from said carrier, varying means for selectively varying the peripheral extent of said exposed portion of said cam; and a sensor mounted on said frame for sensing the exposed portion of each said cam as each of said cam assemblies moves past said sensor during rotation of said cam carrier.

16. A camming system as defined in claim 15, wherein for each said cam assembly: each said cam has opposite longitudinal ends spaced peripherally of said carrier; and wherein each said varying means includes: a hub fixedly secured to one of said longitudinal ends of the associated one of said cams; and mounting means for rotatably mounting said hub on said carrier to enable the associated said cam to be selectively wound onto and off said hub to decrease and increase the longitudinal extent of the outwardly facing exposed portion thereof, respectively.

17. A camming system as defined in claim 16, wherein said sensor includes a finger biased downwardly into the path of travel of said cams successively past said sensor, each of said hubs being positioned at the leading end of the associated said cam in the direction of movement thereof past said sensor and being curved tO guide and raise said finger onto said cam as said cam passes beneath said sensor.

Images