US 2939924 A
Description (OCR text may contain errors)
June 7, 1960 p, FRANCK ROTARY-CAM SWITCH CONTROL DEVICE Filed Aug. 8, 1958 I/VVE/VTOR PIERRE FRANCK 1 M w/M? ATTORNEYS United States Patent ROTARY-CAM SWITCH CONTROL DEVICE Pierre Franck, Paris, France, assign'or to Societe dite: Alkan & Sinay, Paris, France, a French company Filed Aug. 8, 1958, Ser. No. 754,027 Claims priority, application France Oct. 22, 1957 3 Claims. (CL. 200-38) This invention relates to the cyclic control of one or more two-positionswitches. The term switch applies here to any movable member or system for opening or closing one or more electric circuits; each switchv may be for example a simple contact breaker or'break switch, or a reversing switch, or any other switching system.
Itv is the essential object of this invention to provide a rotary-cam device for cyclically controlling one or a plurality of switches. More particularly, this invention provides means whereby, upon each revolution of said rotary cam, the cam-controlled switch is moved firstly from one positionvto its other position, and, after an adjustable fraction of a revolution, from this othertposition to said one or first position, so that the time during which the switch is held in one position is adjustable relative to the time during which it is held in the other position,-the total duration of the cycle being determined] by the velocity of the mechanism rotatably driving the cam.
It is one object of this invention to provide a device adapted to be manufactured at a. relatively low cost under large-scale production conditions by using for example plastic and/or light-alloy mouldings or die-castings.
It is another object of this invention to provide meansfor the phase-shifted. control of a plurality of switches or; switch systems by means of several synchronous rotary carnsdriven from a common mechanism, the common time period during which the switches are held in one of their positions and in the other position being adjustable by means of a same control" device to which all the cams are responsive.
The essentialfeature of this invention resides in that saidrotary cam comprises a face adapted, when the cam is in a predetermined angular position, to lift a control rocker, said control rockerbeing dropped when said cam in moved in an axial direction under the control of an independent cam face associated therewith and adapted to pivot about the axis of rotation, whereby the fall of said rocker takes place when the cam is in an angular position subordinate only to the adjustment of said-associated cam face.
According to a specific form: of embodiment of the invention, the rocker is lifted by the rotary cam when the latter. is in a predetermined angular position, and kept in this raised position by the outer periphery of the rotary cam until the independent cam: face associated therewith causes, the axial movement of the rotary cam against the resistance of a spring topermit the fall of said rocker. along atransverse faceof the rotary-cam, said transverse: facecomprising; aradial slot permitting the axial return; movement ofthe, rotary cam to its initial axial position for re-lifting the rocker.
In order to afford a clearer und'erstandingof the prescnt inventionand of the manner in which the same may be carried out-in thepractice, reference will now be: madev to theaccompanying drawing forming part of this specification and illustrating diagramamticall'y by way ofex- 2,939,924 Patented June 7, 1960 ample two forms of embodiment of the invention. In the drawing:
Figure 1 is. a diagrammatic isometric view showing a rotary-cam device constructed according to the teachingsof this invention for controlling a mercury switch, and
Figure 2 is a diagrammatic isometric view showing on a smaller scale a control board for the cyclic control of mercury switches by means of three rotary cams having a relative timing of that is, one-third of a revolution.
Referring firstly to the device illustrated in Fig l of the drawing, the reference numeral 1 designates a supporting plate or frame carrying an electromotor 2 and a stationary spindle 3 adapted to carry the rotary cam and an adjustment disc associated therewith; mounted on another fixed spindle is. a mercury switch to be controlled, the control means being supported by another fixed spindle 5.
The motor rotor 6 drives through a reduction gearing 7 a toothed wheel 8 solid with a hub 9 rotatable on the spindle 3. The hub 9 has radially threaded thereon a pin 10 carrying a roller 11 engaged by a pair of parallel rods 12', 13 secured in a rotary cam 14 solid with a hub 15; this hub 15 is mounted for rotary and sliding move-- ment on the stationary spindle 3 whereby the roller 11 may drive for rotation the cam- 14 which, while sliding along the spindle 3', may be kept in a fixed angular posi tion relative tothe toothed wheel 8 and its hub 9. In the example illustrated, the cam 14' is mounted on the side oppositeto the hub 9 relative to the wheel 8', and the rods- 12, 13' extend through the flange or disc of this wheel 8; A compression spring 16 is disposed between the hub 9 and cam 14 on the shaft 3-.
The rotary cam 14 is formed with cylindrical outer peripheral contour 17 and a front face 18.
The rotary cam 14 acts radially through its cylindricalouter surface 17' axially through a transverse projecting annular face 18 and comprises a radial slot 19 formed in this transverse-annular face 18 which opens into said outer surf-"ace 17, as shown; the radial edge of the slot 19 which faces the direction of rotation shown by thearrow is designated by therreferenc'e numeral 20. This cam co-acts with a beak 21 formed on the free or projecting end of a rocker 22 carrying a mercury switch 23; this rocker 22 is pivotally mounted on the fixed spindle 4 so that its beak 21' normally bears on the cylindrical outer surface 17- of the rotary cam 14, that is, when the latter is not moved axially against the resistance of the compression spring 16.
Fitted on the cam' hub 15 is a radial pin 24 carrying a roller 25engaging the innerface of a disc 26 pivotally mounted for adjustment purposes on the outer end of the stationary spindle 3. The outer face of this disc 26 car-- ries a graduated-scale; a stationary index 28, carried for example by the outer end of the fixed spindle 4, registers with this dial-forming disc.
On the inner face of the disc 26 the circular path err-- gaged by the roller 25 is formed with: a ramp-forming. projecting cone 29 adapted to move: the assembly consisting of roller 25, cam 14- andhub 15 towards-the support ing plate 1 against the resistance of spring 16. More over,, thedisc 26 carries an externally-toothed. ring 30- constant, meshing engagement, with a pinion 31 mounted for loose rotation on the fixed shaft 5 and adapted tov be. actuated? by means of a control knob 32 permitting the adjustment of the device by rotating the disc 26.
Thev operation of thisidevice is very simple, The rotor 6 of motor 2 drives the. wheel 8. and its hub 9 as well. as the.cam 14 through the medium of the roller 11 and r the pair of rods 12, 13; assuming that the cam 1'4i rotates 23 is closed when the beak 21 of its supporting rocker 22 rests on the outer cylindrical surface 17 of cam 14 (as shown in thick lines in Fig. 1). During the operation of the device, the cam follower 25 engages the cone 29 and the rotary cam 14 is moved axially away from thedisc 26 against the resistance of spring 16, the cam surface 17 escaping from the beak 21to enable the rocker 22 to drop'by gravity to the position shown in chain-dotted lines in Fig. 1, thereby opening the mercury switch 23, the beak 21 subsequently'sliding along the transverse annular face 18 to keep the spring 16 in its compressed condition. Under these conditions, the switch 23 remains open until the slot of cam 19 registers with the beak 21 and permits the movement of the rotary cam 14 towards the disc 26 under the influence of the expanding spring 16. Then, the beak 21 engaged in the slot 19 is acted upon by the radial face 20 of this slot as the cam 14 rotates and the rocker 22 is raised until its beak 21 bears again on the cylindrical outer surface 17 of the cam, thus re-closing the mercury switch 23. This cycle of operation is then repeated under the same conditions.
It is an advantageous feature of the device of this invention that the angular position of cam 14 in which the switch carrier 22 is lifted under the influence of the radial face 20 of slot 19 is determined by construction and that the specific angular position of the same cam in which the switch carrier is dropped depends only on the angular position of the graduated disc 26 associated with this cam, as this fall is caused by the action of the cone or like projection 29 carried by the disc 26; now this angularposition of disc 26 is adjustable at will by rotating the hand knob 32 and consequently the disc 26; the scale 27 enables the operator to move the disc 26 to the desired position to set the opening or breaking time of the switch and consequently the duration of the circuitclosing and circuit-opening periods, the sum of these periods corresponding to the time necessary for the cam 14 to accomplish a full revolution.
In the example illustrated in Fig. 2 of the drawing the driving motor rotates synchronously three cams similar to the cam 14 of the above-described embodiment, these three cams being mounted on a common shaft and having each associated therewith a disc similar to the disc 26 of the preceding embodiment, the adjustment control means permitting the relative angular shift of the three cams through a same angle, whereby the closing and opening periods of the circuits controlled by the three cams may be varied at will while maintaining the closing and opening movements at the same relative angular shift of 120; under these conditions, a three-phase switching system is obtained in the three circuitsor groups of circuits controlled by the device. 7
Referring more in detail to Fig. 2, the device comprises a panel or main'plate 41 carrying an electromotor 42, a rotary shaft 43 driving the rotary cams and supporting the adjustment discs, a spindle 44 adapted to support the rockers carrying the mercury or' like switches, and a rotary shaft 45 adapted to control the angular positions of the adjustment discs.
The rotor of the electromotor 42 drives through a reduction gearing the toothed wheel 46 solid with the shaft 43 on which are keyed three sleeves 47, 48, 49 similar to the hub 9 of Fig. 1, these sleeves being adapted drivingly to rotate three cams 50, 51, 52 similar to the cam 14 of the preceding embodiment and adapted to slide axially against the resistance of springs similar to the spring 16 to return or urge the rollers associated with these cams against three companion adjustment discs 53, 54, 55 mounted for loose rotary motion on the shaft 43; these discs are each provided with a toothed annulus in meshing engagement with respective pinions 56, 57, 58 solid with the shaft 45 and adapted to be rotated by means of an external control knob 59. A graduated drum 60 solid with the shaft 43 permits the proper positioning of this shaft and therefore the setting of the desired relative angular position of the discs 53, 54, 55.
Each disc 53, 54, 55 carries a cone or like projection, similar to the first form of embodiment described hereinabove, which acts on a roller or follower of the cam associated with the disc, as in the case of roller 25. The cams act on the rocking carriers 61, 62, 63 of the three switches 64, 65, 66 which are mounted on the spindle 44.
By construction and assembling the radial slots of the three cams are shifted 120 degrees from one another and the adjustment discs are so keyed or wedged that their projections or cones engage the cam followers for angular positions of the shaft 43 which are similarly shifted 1 by 120; thus, these cones or projections may have the or like projections carried by the discs 5'3, 54, 55 at angular positions of the shaft 43 which are shifted 120 from one another, thereby opening the switches with the same phase shift; similarly, the closing movements resulting cams from a first position to a second position and for from the engagement of the edges'of the cam 'slot's with the beaks of the switch carriers take place also with a interval from one another. .On the other hand, the common shift between the opening and closing moments of these switches may be adjusted at williby rotating the knob-59' to vary the relative angular position of the adjustmentedisc projections or conesfrelativ'e to the cam followers. a V
, It will be readily understood that the forms of embodiment shown in the attached drawing and described here- ,inabove should not be construed as limiting the invention as they merely constitute examples of the manner in which the invention may be carried out in the practice,- for many modifications and alterations may be brought thereto without departing from the spirit and scope of the invention as set forth in the appended claims.
Besides, the velocity of rotation of the cam. or synchronous cams may be rendered variable by providing either a variable-speed electro motor or interposing-a mechanical or electronic variable-speed gear or. device between the rotor of a constant-speed motor and the wheel driving the shaft carrying the cam or the synchronous cams.
According to a particular application of the invention, the rotary cam device can be used for adjusting easily the amount of energy supplied to an electrothermical equipment for convexion or radiation heating by varying the closing and breaking times for the control cyclically operating circuit. In the case of a radiation heating equipment, the cycle is advantageously of only a few seconds in order that the breaking periods are short and do not influence badly the wave length of the heating emission. It may be then suitable to' associate with the device a simple mechanism adapted for suppressing temporarily at will the action of the rotary cam and for ensuring the rocking member to be kept in one or in the other of its two positions; this result'can be easily ob tained by moving the rocking member in the axial direction with respect to the rotary cam.
What I claim is:
1. A rotary cam device for cyclically controlling a number of two-position switches, comprising a plurality of identical rotary cams axially movable on a common rotating axis, means for driving each rotary cam from said common rotating axis, means for driving in rotation said common rotating axis, a plurality of two-position rocking members each operating one, of said switches and adapted for being actuated by one of said rotary being kept by said associated rotary. cam in said second position until said rocking member returns to its first position when said associated rotary cam is disengaged therefrom, separate adjustable means for axially moving in one direction each associated rotary cam when in a predetermined angular position in order to disengage said associated rotary cam from its associated rocking member, spring return means for returning axially each rotary cam in the reverse direction, each rotary cam having on the side of its return axial movement a transverse plane surface along which said associated rocking member has its first position, and common means for rotating by a similar angle around said common rotating axis all said separate adjustable means for moving axially said rotary cams in said one direction.
2. A rotary cam device for cyclically controlling at least one two-position switch, comprising a rotary cam axially movable along its axis, a two-position rocking member operating said switch and adapted for being actuated by said rotary cam from a first position to a second position and for being kept by said cam in said second position until it returns to its first position when said rotary cam'is disengaged therefrom, means for rotatably driving said rotary cam, adjustable means for moving said rotary cam axially in one direction when it is in a predetermined angular position in order to disengage said rotary cam from said rocking member, spring return means rfor returning said rotary cam in the reverse axial direction, and said rotary cam having on the side of its return axial movement a transverse plane surface along which said rocking member has its first position, a peripheral cylindrical surface against which said rocking member rests in its second position, and a slot provided across said transverse plane surface for receiving said rocking member when it registers with said slot, one side edge of which is adapted for actuating 6 said rocking member from said first position to said second position.
3. A rotary cam device for cyclically controlling at least one two-position switch, comprising a rotary cam axially movable along its axis, a two-position rocking member operating said switch and adapted for being actuated by said rotary cam from a first position to a second position and for being kept by said cam in said second position until it returns to its first position when said rotary cam is disengaged therefrom, means for rotatably driving said rotary cam, adjustable means for moving said rotary cam axially in one direction when it is in a predetermined angular position in order to disengage said rotary cam from said rocking member, spring return means for returning said rotary cam in the reverse axial direction, and said rotary cam having on the side of its return axial movement a transverse plane surface along which said rocking member has its first position, said adjustable means consisting of a disc rotatable on the same axis as said rotary cam, a conical cam mounted on said disc, a cam follower carried by said rotary cam for being actuated by said conic cam and means for adjusting the angular position of said disc.
References Cited in the file of this patent UNITED STATES PATENTS 1,392,160 Hipple Sept. 27, 1921 1,701,398 Vickery Feb. 5, 1929 1,915,991 Hammerly June 27, 1933 2,784,276 Pearson Mar. 5, 1957 2,805,293 Daugherty Sept. 3, 1957 2,820,859 Davies et al. Jan. 21, 1958 2,846,892 Roessler Aug. 12, 1958