US3136870A - Cam operated switching mechanism - Google Patents

Description

June 9, 1964 A. T. VAN ECK CAM OPERATED SWITCHING MECHANISM 2 Sheets-Sheet 1 Filed May 14, 1962 //a a W INVENTOR. 4777/0 T MM/ [6K Has.

ATTOKA/f/S June 9, 1964 A. 'r. VAN ECK CAM OPERATED SWITCHING MECHANISM 2 Sheets-Sheet 2 Filed May 14, 1962 3,136,870 CAM OPERATED SWITCHING MECHANISM Arthur T. Van Eek, 300 Dickinson St. SW.,

Grand Rapids, Mich. Filed May 14, 1962, Ser. No. 194,244

9 Claims. (Cl. 200-38) This invention relates to a switching mechanism, and more particularly to a switching mechanism especially suitable as a limit switch and sequence timer, and capable of highly versatile adjustment. This is a continuation-inpart application of my original application entitled Rotary Reciprocating Limit Switch and Timer, Serial No. 140,309, filed September 25, 1961, now abandoned.

Automation advances today are greatly dependent upon elaborate electrical switching mechanisms capable of accuratelycontrolling sequential, timed operations. Using conventional rotary cam-type switches, wherein each cam possesses a configuration formed of lobes and recesses, each and every desired change in any of the sequential operations ordinarily causes great ditficulty in adjusting the switching mechanism. In recent years, rotary cam switches have been produced which are somewhat adjustable. However, the adjustment ordinarily involves a step by step, slow, tedious, time-consuming process. For example, if it is desired to alter the initiation, termination or duration of a particular timed operation, the rotary cam disc controlling that particular operation must be carefully unlocked, rotated, trimmed or shimmed after loosening the discs. It may even be necessary to substitute a new disc, necessitating disassembly of the entire apparatus. Even then, the apparatus must always be completely stopped in order to make adjustments, thereby causing an entire production sequence to be shut down.

Even after the adjustmentis made, the apparatus must usually be started and stopped again to see if the amount of adjustment was proper, or whether too much or too little adjustment was made. Another inherent limitation of rotary switch cams is that the duration of the cycle to be controlled is limited to about 180. Yet these rotary cam switches are widely used today because of the lack of anything better.

It is an object of this invention to provide a switching apparatus enabling rapid and exact adjustment of timing of the initiation, termination or duration of a multiple of operations and with a great deal of flexibility.

It is another object of this invention to provide a switching apparatus enabling adjustment of these operational factors while the apparatus is in operation.

It is another object of this invention to provide a switching apparatus adapted to employ a large number of switch actuating means, wherein each means is adjustable without interference with the other adjacent means, and without disassembly of parts, or unlocking of cams or look nuts. Further, the adjustment may be made by small increments of any size to achieve the exact result desired, even during operation.

It is another object of this invention to provide a switching or timing apparatus wherein the cams of the camming means causing actuation and deactivation of the switching means can be moved toward and away from each other very readily, unlike the limited and fixed circumferential camming surface associated with a rotary cam.

It is a further object of this invention to provide a switching apparatus capable of combining a reciprocating switch-camming action with a rotary switch-camming action, especially for operating a multiple throw switch.

It is still a further object of this invention to provide a sequential control switching apparatus capable of combining reciprocating and rotary camming actions in a manner to cause making of a second switch connection before breaking of a first switch connection.

These and many other objects of this invention will be apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a perspective view of one form of the novel switch apparatus driven by suitable power means;

FIG. 2 is a perspective view of one form of the novel apparatus illustrated in FIG. 1, with the top, front, and back covers removed;

FIG. 3 is a side elevational, sectional view of the apparatus illustrated in FIG. 2 taken on plane IIIIII;

FIG. 4 is a fragmentary side elevational, sectional view similar to that of FIG. 3, but with the switching mechanism in a different position;

FIG. 5 is another sectional, fragmentary, elevational view similar to FIG. 3, but with the switching mechanism in still another position;

FIG. 6 is a perspective view of two camming portions forming one adjustable cam means for part of the switching apparatus illustrated in FIG. 2;

FIG. '7 is a side elevational, sectional view showing a. modified form of the invention;

FIG. 8 is a top plan view of the apparatus illustrated in FIG. 7; and

FIG. 9 is a front elevational, sectional view of another modification of the apparatus.

Basically, the inventive switching apparatus comprises a reciprocal carriage having elongated cam surface means on opposite sides adapted to actuate and deactivate switch means with reciprocation of the carriage. Preferably, a rotary cam means on a driven shaft causes reciprocation of the carriage. The elongated cam surface means on the carriage is formed of a plurality of portions which are adjustable with respect to each other and with respect to the switching means. Alternatively, the switching means mounted on the housing means of the apparatus 7 a rotary cam means for simultaneous actuation of the switch means, and movable independently of, but in timed relationship, to the reciprocating carriage. The rotary cam means is preferably mounted on a drive shaft which causes reciprocation of the carriage when the shaft rotates. The rotary cam means is especially adapted to open and close selected ones of a plurality of contacts of a multiple throw switch independently of, but in timed relationship to, opening and closing of other contacts by the elongated, reciprocating cam surface means. The elongated camming means on one side of the housing controls of the switching cycle and the camming means on the opposite side controls the second 180 of the cycle. The rotary cam throws the control from one side to the other between the down and up strokes of the reciprocating carriage. The rotary cam also causes the multiple throw switch contacts to close to continue the circuit'before 7 other contacts open to break the circuit.

Referring to the drawings, the switchingapparatus 10 is shown in FIG. 1 driven by a suitable means 12 which may include a suitable variable drive motor, sheave 14, belt 16 and pulley 18. These rotate drive shaft 20 of the switching apparatus to operate the apparatus on a timed basis.

The mechanism 10 includes a suitable housing having a removable front cover 22, a movable back cover 24 and a removable top 26 in the form of the invention illustrated. These may be all one integral cover. Of course, the housing structure may be modified in a number of ways.

, c9 In the housing, a carriage means 30 having a lower platform 32 and an upper platform 34 is located. It can reciprocate vertically as guided by a pair of tracks 36 on opposite sides of the housing interfitting in recesses in the carriage. The carriage is reciprocated by a pair of rotary cam driving discs 38 mounted adjacent side walls 40 and 42 of the housing and attached to shaft to be rotated thereby. The platform 32 includes a pair of downwardly extending legs 44 and 46 having laterally projecting feet 48 under cams 38. The cams lower the carriage by contact with these feet, and raise it by contact with platform 32. A pair of vertical slots in legs 44 and 46 enables the legs to move up and down over the driving shaft 20.

Shaft 20 is journaled in suitable bearings 52 in the side walls, and 42 of the housing. Thus, in brief, rotation of shaft 20 causes rotation of driving cams 38 to first raise the carriage by contact with platform 32 and then lower the carriage by contact with feet 48.

In the form of the invention illustrated in FIG. 2, two

groups of longitudinal switch actuating means 60 and 62 are shown mounted on carriage 36 Each of these is adapted to cooperate in a unique manner with camming means on the opposite side of the carriage to actuate a switching means 64 mounted adjacent the bottom of the housing. Thus, in the structure shown, actuating means 62 is adapted to cooperate with actuating means 61 (FIG. 3). Actuating means 611 is entirely independent of these. It is included only to show how a plurality of units can be operated from the same drive shaft. Thus, the invention will be described with respect to a first actuating means 62 on one side of the carriage and a second actuating means 61 on the opposite side of the carriage to actuate switch means 64 utilizing the pivotlevers 66 and 67. The switch means actuated by means 60 is not illustrated, since it would operate on basically the same principles and its inclusion would confuse the drawing.

Each actuating means 62 is composed of a plurality of camming portions or elements. In the form of the invention illustrated, two such portions (FIG. 6) 8t) and 82, each of simple configuration, are shown for each camming means. Preferably these portions are generally L-shaped in cross section so that the base of the L may be mounted in receiving channels in the carriage 31). The protruding leg of the L portions each has partial camming surfaces e.g. 84 and 86, respectively, which cooperate to form a cooperative cam surface 85 for the roller element 88 of the pivotal lever 66. Likewise, actuating means 61 includes two elements which form camming surface 87 for roller 89.

Each of the respective camming portions e.g. 8t and 82 are adjustably mounted on screws 10 and 92 (FIG. 6) having heads .94 and 96 which remain stationary with respect to the upper platform 34 of the carriage, since the washers 98 and 99 lock the screws to the platform as shown in FIG. 3. Thus, by rotation of the screws, the camming portions may be vertically adjusted both with respect to the carriage and with respect to each other to produce the desired cooperative camming action in a manner to be explained more fully hereinafter. In FIG. 3, the portions forming surface 85 have spaced off lobes with an intermediate on recess. The portions forming surface 87 have overlapping off lobes and spaced on recesses. Obviously, the variety of possible relationships is extremely large.

Each pivot lever (66) is rotatably mounted on a pivotal shaft (100) which in turn is mounted between a pair of ears (102 and 104) projecting from the side walls (40 and 42) of the housing. The pivot lever 66 oscillates around shaft 100 as the roller element 88 glides over the vertically reciprocating camming surface 85 formed by the cooperation of back legs 84 and 86. Each of these back legs has lobes and recesses thereon as desired, here shown in the simplest form to facilitate understanding of the invention. The lever on the opposite side is mounted similarly and operates according to the same principles.

The switch means 64 is here shown as a double throw switch means utilizing leaf spring electrically conducting elements 106, and which project from both sides of mounting means 70. Also a pair of central leaf elements 108 and 111 which are insulated from each other are provided. Associated with the upper spring element 110 are interconnected spring bumper leaves 112 and 120 which pivot on pin 127 to shift and control the two ends of leaf 110. In operation the central leaves 168 and 111 remain substantially stationary. The two ends of leaf 106 are shifted and controlled by the respective levers 66 and 67. In the form of the invention illustrated in FIG. 3, foot 114 of pivotal lever 66 is adapted to depress the right end of metallic leaf 106 to separate contacts 116 and 118a. Foot can depress the left end of leaf 166 to separate contacts 121 and 123a. Spring leaf 112 cooperates with leaf 110 to raise and depress leaf 110 and thereby place contact 119 into operative electrical engagement with contact 1181;. Dog leg spring projection 120 is integrally associated with leg 112 to serve to depress leaf 110 to make this second electrical circuit when roller 122 is shifted clockwise by contact with semi-circular cam 124 mounted on shaft 20. Cam 124 may conceivably be rotatably adjustably mounted to shaft 21) so that it can be swiveled around to give the proper relationship as desired. The left end of bumper leaf 120 is adapted to separate contacts 125 and 12% when roller 122 is in contact with cam 124. When roller 122 is allowed to shift into contact with shaft 26, it pivots counterclockwise on pin 127 to depress the left end of leaf 112 and thus contact 125 into engagement with contact 123b.

In the form of the invention illustrated, an electrical lead 131 is made to leaf 106 and a second electrical lead 133 is made to leaf 116.

Cam 124 on shaft 20 determines which actuation means 61 or 62 controls the circuit. For example, if the cam 124 contacts roller 122 to rotate levers 120 and 112 clockwise, this engages contacts 119 and 11% and disengages contacts 125 and 123b. Then whenever contacts 118a and 116 engages a circuit will be completed between leads 131 and 133. However, even though contacts 121 and 123a engage, since contacts 123]; and 125 are disengaged, no circuit can be formed on the left end of the mechanism. Cam 124 is located on the shaft to cause this to occur When the carriage is moving downwardly. Thus, actuation means 62 controls the circuit during the downstroke, or i.e. during the first of the operation. During the upstroke of the carriage as illustrated in FIG. 5, roller 122 moves off rotating cam 124 and into contact with the shaft 26. This allows levers 112 and 120 to rotate counterclockwise to depress the left end of leaf 110 and engage contacts 125 and 123b, while opening contacts 118b and 119. Therefore, when contacts 121 and 123a are engaged, a circuit is made through lead 131, contacts 121 and 123a, contacts 1231) and 125 and lead 133. Therefore, cam 12 1 causes actuation means 61 to control the circuit on the upstroke or i.e. the second 180 of the cycle.

It will be obvious that closing of contacts 118a and 116 occurs when roller 88 of lever 66 is in an on recess to complete the circuit on the downstroke. Closing of contacts 123a and 121 occurs when roller 89 is in an on recess to complete the circuit on the upstroke.

In order that the circuit through leads 131 and 133 may be continued without a shut off as the carriage changes direction at the bottom and/or at the top of its reciprocating strokes, cam 124 preferably extends some- What less than 180 around shaft 21). Thus as seen in FIG. 4, for example, as the carriage reaches the bottom (after FIG. 3 and before FIG. 4) contacts 119 and 11% do not disengage until contacts 1233b and 125 engage. This effects a make before break so that the circuit is not disrupted during half-cycle changeover. A disruption could cause relays in the electrical system to be thrown out, for example.

'By adjusting screws 94, 96 etc. protrudingfrom the top of the housing, the position of the respective portions forming the cam surfaces may be Widely adjusted to vary the initiation of the switch opening and switch closing, and to vary the duration of a particular switch closing period. Also, adjustment can even be made While the unit is in operation merely by inserting a screw driver to adjust a screw.

As the cam 38 continues to rotate further, the vertically arranged camming surface 85 may be utilized to break the circuit formed between contacts 116 and 118a as desired. Obviously, the variations between the rotary camming means and the reciprocating camming means are many, since not only can the reciprocating cam portions forming the reciprocating camming means 85 be varied with respect to each other, but also may be varied with respect to the rotary camming means. Consequently,

the resultant switching apparatus is highly versatile in operation. Further, the reciprocating camming surface means may be adjusted while the device is still in operation to vary'the times of initiations of particular sequenrange.

- Modification In FIGS. 7 and 8 is shown a first modification of the apparatus illustrated in FIGS. 1 through 6. In this modification the vertical adjustment of the switching means with respect to the reciprocating camming means is even simpler since the adjusting screw 130 remains completely stationary duringoperation of the apparatus. In this form of the invention, instead of the switching means 164 being mounted adjacent the base of the housing, it is mounted within the front 22 of the housing so that by adjustment of threaded screw 132 with head 130, the switch supporting bracket 134 can be vertically raised or lowered to raise and lower roller element 136. Carriage 30 again moves in a guided fashion due to tracks 36 fitting within corresponding recesses in the carriage as illustrated in FIG. 8. The carriage is vertically reciprocated by cam 38 moving the carriage up by contact with platform 32 and moving it down by contact with feet 48 on legs 54. If desired, the cam surface means 85 may also be adjustable with respect to the carriage and may be formed as illustrated in FIG. 6. On the other hand, I

this camming surface 85 may be a unitary element afiixed to the carriage 30 in a suitable manner. Reciprocation of the carriage allows roller 136 on spring leaf 138 to move into recesses, and unto lobes against its bias to actuate the switch button 140.

Of course, this is a very simple form of the broadest aspects of the invention and as shown does not possess the refinements, versatility, or control capacity of that form illustrated in FIGS. 1 through 6.

In FIG. 9 is illustrated another modification of the apparatus. Here the camming surfaces 285 and 287 are each formed by a pair of elements or slidable portions which are adjustably mounted to the top of the housing 212. Adjustment screws 204 are provided for each ele- 214 and 216 respectively of switches 218 and 220 mounted to reciprocating carriage 222. Rotary cam discs 206 on shaft 208 reciprocate the carriage as before. The carriage may be guided by having a central leg 221 project into slot 225 in the mounting means for the elongated camming elements. The respective switch arms operate sliding pins 223 and 224 which open and close a pair of contacts 226 and 228 in each switch.

To provide one of the camming surfaces 285 and 287 with control of the circuit on the downstroke of the carriage 222, and the other with control on the upstroke, rotary cam 234 is provided on shaft 208. When roller 236 contacts cam 234, it closes contacts 238 to allow 6 switch 220 to control the circuit. When contacts 240 are closed as shown, switch 218 controls the circuit. This form of the invention affords very simple adjustment of the longitudinal camming surfaces during operation.

It will thus be realized by those in the art, that the novel apparatus removes the many limitations inherent in a rotary cam switch apparatus. It basically enables the use of generally linear camming surfaces unlimited to the peripheral dimension of a circular type cam. Furthermore, his highly adjustable, even during operation of the apparatus. Moreover, it enables a combination of a rotary cam actuating switch means and a reciprocating cam actuating switch means to produce a make before break action for a sequential switching mechanism. Several other advantages not specifically mentioned will occur to those in the art upon studying the foregoing specification and the forms of the inventiondepicted. Further, various obvious modifications of the depicted apparatus within the inventive principles taught, will occur to those in the art to suit a particular application of the mechanism. Such obvious modifications are deemed to be part of this invention which is to be limited only by the scope of the appended claims and the reasonably equivalent structure to those defined therein.

I claim:

1. Switch apparatus comprising: reciprocal carriage means; driving means adapted to reciprocate said carriage means; cam surface means arranged longitudinally of said carriage means; switching means in operative association with said cam surface means and including an elongated shiftable element engaging said switching means and having a rider in engagement with said camsurface means; said carriage means, when reciprocated, causing said shiftable element and cam surface means to be moved with respect to each other to cause said rider to move over said cam surface means; said cam surface means vincluding a plurality of segmental, independently and means adapted to adjust the relative position of said cam surface means and thereby control the time and duratlons of actuation of said switch means; and rotary cam control means on said drive shaft and also operably associated with said switch means, to control the electrical actuation of said switch means by the respective actuatmg means on opposite sides of said carriage, whereby switch actuation control can be achieved over 360 of rotation of said drive shaft with control on the upstroke and downstroke of said carriage with said rotary cam control means.

3. Switch apparatus comprising: rotary cam driving means including a drive shaft and rotary cam means; reciprocal carriage means operatively associated with said rotary cam driving means to be reciprocated thereby; cam surface means arranged longitudinally of said carriage means; and switch means in operative association with said cam surface means; said switch means being mounted on support means adjacent said carriage means; said cam surface means comprising a plurality of cam portions arranged longitudinally on said carriage means and cooperating to form a single variable cam means for each switch of said switch means; each of said cam portions being slidable with respect to said carriage and including an elongated adjustment screw means upon which it is threadably mounted, whereby the individual cam elements can be independently adjusted longitudinally of said carriage and with respect to the switching means to enable independent variation of switch actuation, deactivation, and total time of the switch activation cycle.

4. A versatile switch apparatus comprising the combination of: switching means including a plurality of contacts; reciprocating carriage means including a pair of longitudinal cam surface means adapted to operate said switching means; rotary cam means adapted to move independently of but in timed relationship to said reciprocating cam surface means; and said rotary cam means also being in operative relationship to said switching means and adapted to actuate said switching means in two steps to cause one of said pair of longitudinal cam surface means to operate said switching means on the stroke of said carriage in one direction, and the other of said pair to operate said switching means on the stroke of the carriage in the opposite direction.

5. Switch apparatus comprising: double throw switching means having a plurality of contacts capable of making and breaking an electrical circuit through either of two sets of contacts; reciprocating carriage means having a first camming means adapted to open and close part of one set of contacts and second camming means adapted to open and close part of the second set of contacts; rotary cam means adapted to move simultaneously with and in timed relationship to said reciprocating camming means; said rotary cam means being adapted to alternately close the other part of the two sets of contacts to allow control of said circuit through one set and then through the other as operated by said camming means; and said rotary cam means being timed with respect to said reciprocating cam means to close parts of both sets of contacts during changeover to cause said circuit to be made through one set before broken through the other set.

6. Switch apparatus comprising: double throw switching means having a plurality of contacts capable of making and breaking an electrical circuit alternately through two sets of contacts; reciprocating carriage means having a first camming means adapted to make and break said circuits by closing and opening said contacts; rotatable drive shaft means; driving cam means on said shaft means adapted to reciprocate said carriage means; rotary cam means mounted to said drive shaft and adapted to move simultaneously with and in timed relationship to said reciprocating camming means; said rotary cam means also being adapted to make and break said circuits by closing and opening said contacts; and said rotary cam means being timed with respect to said reciprocating cam means to cause said circuit to be made through one set before broken through the other set.

7. Switch apparatus comprising: double throw switching means having a plurality of contacts capable of making and breaking an electrical circuit alternately through parallel paths; reciprocating carriage means having a first longitudinal camming surface means adapted to make and break said circuit by closing and opening the contacts for one path; a second longitudinal camming surface means adapted to make and break said circuit through the second path; rotatable drive shaft means;

driving cam means on said shaft means adapted to reciprocate said carriage means; said first and second camming surface means each comprising a plurality of cam elements arranged longitudinally of said carriage means; each of said cam elements being adjustable with respect to said carriage and to each other; a rotary cam means mounted to said drive shaft and adapted to move simultaneously with and in timed relationship to said first and second reciprocating camming surface means; said rotary cam means being adapted to control contacts in said first and second paths; and being timed with respect to said first and second camming surface means to cause said first camming surface means to make and break said one path during movement of said carriage in one direction, and to cause said second camming surface means to make and break said second path during movement of said carriage in the opposite direction.

8. A switch apparatus comprising: switching means including a plurality of contacts; reciprocating carriage means; a drive shaft and rotary cam drive means to reciprocate said carriage means; a pair of adjustable elongated cam means; shiftable means between said switching means and said elongated cam means to operate said switching means with reciprocation of said carriage; ro tary cam means on said drive shaft, independent of said pair of elongated cam means, but operatively synchronized therewith, and being in operative relationship to said switching means, causing one of said pair of elongated cam means to control said switching means on the upstroke of said carriage, and the other of said pair of elongated cam means to control said switching means on the downstroke of said carriage, thereby obtaining variable switching action through 360 of said drive shaft rotation.

9. A switch apparatus comprising: switching means including a plurality of contacts; reciprocating carriage means; a drive shaft and rotary cam drive means to reciprocate said carriage means; a pair of adjustable elongated carn means; shiftable means between said switching means and said elongated cam means to operate said switching means with reciprocation of said carriage; said shiftable means including a pair of elongated elements each having a follower on one end contacting one of the pair of elongated cam means to follow the contour thereof and depress the switching means in a controlled fashion to open and close a circuit; rotary cam means on said drive shaft, independent of said pair of elongated cam means, but operatively synchronized therewith, and being in operative relationship to said switching means, causing one of said pair of elongated cam means to control said switching means on the upstroke of said carriage, and the other of said pair of elongated cam means to control said switching means on the downstroke of said carriage, thereby obtaining variable switching action through 360 of said drive shaft rotation.

References Cited in the file of this patent UNITED STATES PATENTS 2,058,553 Beiderman Oct. 27, 1936 2,658,123 Von Stoeser Nov. 3, 1953 2,941,051 Laviana June 14, 1960 2,951,920 Miller Sept. 6, 1960

Claims (1)

1. 4. A VERSATILE SWITCH APPARATUS COMPRISING THE COMBINATION OF: SWITCHING MEANS INCLUDING A PLURALITY OF CONTACTS; RECIPROCATING CARRIAGE MEANS INCLUDING A PAIR OF LONGITUDINAL CAM SURFACE MEANS ADAPTED TO OPERATE SAID SWITCHING MEANS; ROTARY CAM MEANS ADAPTED TO MOVE INDEPENDENTLY OF BUT IN TIMED RELATIONSHIP TO SAID RECIPROCATING CAM SURFACE MEANS; AND SAID ROTARY CAM MEANS ALSO BEING IN OPERATIVE RELATIONSHIP TO SAID SWITCHING MEANS AND ADAPTED TO ACTUATE SAID SWITCHING MEANS IN TWO STEPS TO CAUSE ONE OF SAID PAIR OF LONGITUDINAL CAM SURFACE MEANS TO OPERATE SAID SWITCHING MEANS ON THE STROKE OF SAID CARRIAGE IN ONE DIRECTION, AND THE OTHER OF SAID PAIR TO OPERATE SAID SWITCHING MEANS ON THE STROKE OF THE CARRIAGE IN THE OPPOSITE DIRECTION.

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