US 3495203 A
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Description (OCR text may contain errors)
Fel-1.410, 1970 1 J. NEUBAUER 3,495,203
SWITCH Filed Oct. 2, 1968 3 Sheets-Sheet 1 BVM f' ya ATTORNEYS Feb. 10, 1970 J. NEUBAUER SWITCH Filed 001'.. 2, 1968 3 Sheets-Sheet 2 TTORNEYS Feb. 1o, 1970 J. NEUBAUER 3,495,203
SWITCH Filed oet. 2, 196e s sheets-sheet a F/G. 7 5 44 a f //l/fmzz/cfzim/r W I il M T Wwf/ge HTTORNE YS United States Patent O 3,495,203 SWITCH i Josef Neubauer, Wendelstein, Germany, assigner to Firma Diehl, Nuremberg, Germany Filed Oct. 2, 1968, Ser. No. 764,495 Claims priority, application Germany, Oct. 19, 1967,
Int. -cl Hoih 71 /16 U.S. Cl. 337-81 13 Claims ABSTRACT F THE DISCLOSURE BACKGROUND OF THE INVENTION There exist various types of electric timing switches operating in a stepwise manner, in which the switch is moved, step by step, by intermittently heating and cooling a bimetallic element.
There also exists a switch in which the actual switching is done by a spring and in which an intermittently heated bimetallic element does nothing other than to regulate the escape movement or run-off of the actuating element proper, i.e. a switch in which the bimetallic element itself does not carry out any switching operation but serves only periodically to free and to block a spring-driven switching element, such as a stepping wheel. Such an arrangement, which is shown, for example, in German Patent No. 514,837, has been found to operate much more accurately than switches in which the switching work is done by the bimetallic element itself.
Another switch operating on this principle is shown in Ger-man Gebrauchsmuster 1,908,042. That switch incorporates an actuating slide which is operatively connected with a stepping wheel and which is used to wind up a spring that urges the stepping wheel to rotate in a direction in which the parts are returned to their starting position. Here, the stepping wheel is blocked and unblocked, in a stepwise manner, by a bimetallic element acting via an escapement element. The drawback of this type of switch, however, is not only that it requires relatively sensitive horological components, but also that it is diicult, if not impossible, to preset such a switch to precisely the desired run-olf time by depressing the slide to a greater or lesser extent.
It is therefore the primary object of the present invention to provide a push-button type timing switch which overcomes the above drawbacks, namely, a timing switch which is robust, which is insensitive to ambient temperature fluctuations, which can be actuated so as to stay closed for a period of time depending on how far the push-button is depressed, and which can easily be turned 01T at any time, preferably by actuation of the pushbutton.
BRIEF DESCRIPTION OF THE INVENTION With the above objects in view, the present invention resides in a push-button type timing switch which has an actuating element that can be depressed against the action of a spring and which, in depressed position, maintains contacts in closed position. The actuating element has associated with it a timing mechanism which is controlled by an electrically heated bimetallic element. The timing mechanism itself controls the heater for the bimetallic element and alternatively switches the heater on and olf, the arrangement being such that the actuating element is allowed to return to its starting position in a stepwise manner.
More particularly, the present invention relates to a push-button type timing switch in which an actuating element is mounted for sliding movement in a frame, there being a ratchet lever coacting with the actuating element. This ratchet lever has a number of steps. The frame iS provided with xed abutment means which are engaged by the side of one step of the ratchet lever and by the front of the subsequent step, with spring means being provided to urge the steps toward the xed abutment means. Movable abutment means are arranged next to the fixed abutment means and are moved by bimetallic moving means in such a way that the movable abutment means move into and out of alignment with the Xed abutment means. P[he bimetallic moving means are periodically heated and allowed to cool, so that upon heating, the movable abut-ment means are moved out of alignment with the fixed abutment means. This raises the step of the ratchet lever off the tixed abutment means until, under the influence of the spring means, the front of the subsequent step comes into engagement with the movable abutment so that the latter, in effect, takes over the abutment function of the xed abutment means. After cessation of heating, the bimetallic moving means return the movable abutment means back into alignment with the xed abutment means, thus unblocking the previously engaged step and allowing the ratchet lever to move under the inuence of the spring means so that the side of the subsequent step and the front of the next subsequent step of the ratchet lever come into engagement with the fixed abutment. In this way, the ratchet lever, and with it the actuating element, are returned to a rest position, under the inuence of the spring means, in a half-step by half-step manner at a rate which is determined by the rate at which the bimetallic moving means are heated and allowed to cool.
The number of heating and cooling cycles, and hence the run-off time, depends on how far the actuating element is depressed.
According to a further feature of the present invention, the ratchet lever is lifted off the abutment means when the actuating element is completely depressed, so that the switch can be returned to its olf position before the run-off time has elapsed.
Thanks to the above structure, there is obtained a robust switch which does not require any particularly sensitive parts, which can be set to stay closed for any one of a number of different periods of time, which can be reset to its oit position whenever desired, and which will, in general, yield precisely predictable run-olf periods.
BRIEF DESCRIPTION `OF THE DRAWINGS FIGURE l is a plan view of one embodiment of a push-button type timing switch according to the present invention, the switch being shown in its off or starting position, i.e., the parts are shown in the positions which they occupy before the switch is actuated.
FIGURE 2 is a sectional plan view of the switch of FIGURE 1 taken on line II-II of FIGURE 5, the parts now being shown in a first on position.
FIGURE 3 is a fragmentary sectional plan view similar to FIGURE 2 except that the parts are shown in the positions they occupy when the switch has been actuated in such a way as to provide maximum run-off time.
FIGURE 4 is a fragmentary sectional plan view similar to FIGURES 2 and 3 except that the parts are shown in the positions they occupy at the instant in which the timing mechanism is released manually for the purpose of resetting the switch.
FIGURE 5 is sectional side elevation taken on line V-V of FIGURE 1.
FIGURE 6 is a fragmentary sectional side elevation of a locking mechanism forming part of the switch shown in FIGURE 1, FIGURE 6 being taken on line VI-VI of FIGURE 4.
FIGURE 7 is a plan view of another embodiment of a push-button type timing switch `according to the present invention, the parts being shown in the positions they occupy when the switch has been actuated so as to provide the maximum run-off time.
FIGURE 8 is a sectional side elevation taken on line VIII-VIII of FIGURE 7.
FIGURE 9 is a sectional bottom view showing the underside of the switch taken on line IX-IX of FIGURE 8, the parts being `shown in the positions they occupy when the switch has been actuated so as to provide maximum run-off time.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and first to FIGURES 1 to 6 thereof, the same show a push-button type electric timing switch incorporating a U-shaped frame 1 into which is inserted a bottom plate 2. An actuating element 3 which carries, at the left-hand end, as viewed in the drawings, a push-button 4, is mounted on the frame i1 and bottom plate 2 so as to be slidable with respect thereto against the force of a tension spring 5. One end of the spring 5 engages a slide 12, to be described below, while the other end is hooked into an eye 6 which is part of a stepped ratchet lever 7, the latter being pivotally mounted on the actuating element 3 by means of a screw 8. The eye 6 is laterally oiset with respect to the pivot axis afforded by the screw 8 such that the spring 5 which acts on the element 3 simultaneously applies a continuous force to the ratchet lever 7 which tends to rotate the lever 7 in counter-clockwise direction, as viewed in the drawing. The lever 7 has, at its free end, laterally directed steps 9. In rest position, the ratchet lever 7 lies against a xed abutment 10 of frame 1, immediately next to which there is arranged an abutment tongue 11 of the above-mentioned slide 12, the same being mounted for movement in a direction transverse to the direction in which the actuating element 3 moves. The slide 12 is carried by two bimetallic strips 13 and 14, whose right-hand ends are secured to a bracket =15 which, in turn, is screwed to the bottom plate 2 and is transversely dsplaceable, thereby to allow the starting position of the movable abutment 11 to be regulated. The bimetallic strip 13 carries a heater winding 16, so that when this heater is energized by means of an electric current, the strip 13 is deflected, the arrangement of the components of the bimetallic strip 13 being such that when the heater winding 16 is energized, the left-hand end of strip 13 is moved upwardly, again as viewed in the drawing, and thus in a direction away from the bimetallic strip 14. The components of the second, compensating bimetallic strip =14 are so arranged that lwhen the strip 14 is heated, its left-hand end is deflected downwardly, i.e., away from the strip 13. The two bimetallic strips 113, i14 thus act in opposition to each other and thus eliminate the eiect of ambient temperature uctuations. Consequently, so long as no curshown in FIGURE 3, the ratchet lever 7 has, at its end face near the pivot screw -8, an oblique camming edge 17 which, when the ypush-button 4 is completely depressedsee FIGURE 4-strikes against the bracket 15 so that the ratchet lever 7 is pivoted in clockwise direction against the action of the return and pivot spring 5. In the course of this, the steps 9 are raised oit the abutment A10.
The ratchet lever 7 carries a leaf spring 18 which is secured to the ratchet lever and which, as is best shown in FIGURE 6, has a projection 19 that extends through a cut-out 20 of the ratchet lever 7 into a recess 21 of the actuating element 3, Iwhen the ratchet lever 7 is pivoted beyond its normal position as the camming edge 17 strikes the bracket 15. The leaf spring 18 additionally has an upwardly bent tongue 22 which, when the actuating element slides back into its rest position, comes into engagement with a xed abutment tongue 23 that is part of the frame 1 and which lifts the leaf spring 18 off the ratchet lever 7, assuming the latter to have been moved into position wherein the projection 19 extends into the recess 21 of the actuating element 3.
The actuating element 3 has firm-ly connected to it a plate 24 which carries bridging contacts 25, the latter coacting with stationary contact blades or terminals 26, 27, 28, 29, that are mounted on a base plate 30 made of insulating material. The base plate 30 is connected by means of pins or the like with the frame 1 of the switch. The terminals 26, 27, 28, 29, themselves are molded or riveted to the base plate 30` and have knife-edge ends which project through an insulating strip 31.
The base plate 30 is, furthermore, provided with a resilient contact slide 32 which coacts with transversely extending Contact strips 33, 34, 35, on the plate 24. This contact slide 32 coacts with the contact strips 33, 34, 35 to control the heating current flowing through the heater winding 16 of the working bimetallic strip 13. Accordingly, contact 32 is yconnected to one end of the heater winding 16, the terminal 28 being connected to the other end of the heater winding. The contact strips 33, 34, 35, are all connected to that bridging contact 25 which, when the switch is turned on, i.e., when the push-button is depressed, is in electrically conductive contact with the terminal 26.
The switch shown in FIGURES 7, 8 and 9 is essentially similar in construction, except that the ratchet lever 7 is at right angles to the actuating element 3 and is pivotally mounted thereon. The function of the oblique camming edge 17 is taken over lby an abutment 36 which, when the actuating element 3 is fully depressed, pivots the ratchet Vlever 7' in counter-clockwise direction.
In lieu of the two bimetallic strips which bow in opposite directions as the result of ambient temperature changes, the embodiment of FIGURES 7 to 9 incorporates a conventional U-shaped double bimetallic element, the same including a cross piece 37 which is pivotally mounted on the frame and two bimetallic strips 318, 39 Welded to this cross piece, the components of these strips being so arranged that when the elements bow as the result of temperature variations, they do so in the same direction. Here, the compensating effect is obtained not by equal and opposite forces, but by equal deections of the bimetallic strips 38, 39, from their respective rest positions, as is conventional, for example, in electric ranges.
The bimetallic strip 38 carries a heater winding 40,
axial position of the groove 43 and hence the position of the free end of the bimetallic strip 38 can be regulated.
A leaf spring 45 is provided for the purpose of holding the ratchet lever 7' after it has been reset by depressing the push-button, this leaf spring 45 being adjacent the ratchet lever 7 and having a bent-over tongue 46 which detents into the stepped portion of the ratchet lever 7 when the same has been pivoted in a counter-clockwise direction. This ratchet lever 7 is released by means of a ramp -47 with which the frame 1 is provided and onto which runs a free, upwardly bent end 48 of the leaf spring 45.
The above-described elements can be kinematically inverted, in that instead of pivotallyl mounting the ratchet lever 7, 7 on the actuating element 3 and providing the stationary abutment 10, 42, which is lixed on the frame, the ratchet lever 7, 7' can be pivoted on a fixed point on the frame and the abutment can be arranged on the actuating element 3 or be actuated by it.
The operation of the switch is as follows:
Assume that the switch is initially in the position shown in FIGURE 1 and that this switch is to be turned on and to Istay closed for a short period of time, i.e., that the switch is to be actuated so that the parts occupy the position shown in FIGURE This is done by depressing the push-button 4 and with it the actuating element 3, but only so far until the rst step 9c (FIGURE 4) of the ratchet lever 7 comes to lie on the abutment 10. The edge 9d of the step lies against the side of the abutment 10. The terminals 26 and 27 are electrically connected to each other by way of one of the bridging contacts 25. Moreover, the transverse contact strip 33 is now in contact with the contact slide 32, so that the heater winding 16 which is now connected to a supply voltage (not shown) via the terminals 28, 29, has current flowing through it. The bimetallic strip 13 is heated until the abutment tongue 11 of the ratchet lever 7 is raised Sulliciently to allow the step edge 9d tov slide away over the abutment 10 and to come to lie against the movable abutment 11 which, now being out of alignment with the Iixed abutment 10, in effect takes over the function of this abutment 10. The ratchet lever 7 has thus now moved back toward its starting position, under the inuence of the spring 5, by what may be considered a halfstep. In the course of this movement, the contact-carrying plate 24 will also have moved back a half-step, as a result of which the conta-ct slide 32 will now come to engage the undersurface of the plate 24 at a point between the transverse contact strip 33 and the next contact strip 34, the spacing between these two strips and all of the transverse contact strips being such that the contact slide 32 is out of contact with any transverse contact strip whenever the plate is in such a half-step position. As a result, the heater 16 is turned off and the bimetallic strip 13 is allowed to cool. This, in turn, causes the slide member 12 and hence the movable abutment 11 to return to the original position behind and in alignment with the fixed abutment 10 so that the side of the next step can come into engagement with the fixed abutment 10. This, then, causes the ratchet lever 7, and with it the actuating element 3 and the plate 24, to undergo the second half-step of this particular cycle. Upon the completion of this second half-step, electrical contact is established between the slide 32 and the next transverse contact strip 34, so that the heater 16 is once more turned on and the next cycle, consisting of two half-steps, is initiated. In this way, the parts are returned into the starting or ofi position of the switch, under the inhuence of the spring 5, in a half-step by half-step manner at a rate which is determined by the rate at which the bimetallic strip 13 is heated and allowed to cool.
If the switch has been depressed too far, or if the switch is to be turned to its olf position before the time for which it has been set has elapsed, this can be done by pressing the push-button 4 all the way in, and this will cause the actuating element to be returned to its starting position, corresponding to the olf position ofthe switch, as follows: the oblique camming edge 17 of the ratchet lever 7 will, with the spring 5 becoming tensioned, come to lie against the base of the frame 15, which causes the ratchet lever 7 to pivot in clockwise direction until the projection 19 of the leaf spring 18 (FIGURE 6) dips into the recess 21 of the actuating element 3. In this position, the actuating element 3 can, as is apparent from FIGURE 4, return to its starting position under the inlluence of the spring 5. The steps 9 of the ratchet lever 7 pass over the abutment 10 and the abutment tongue 11. Once the actuating element 3 is back in its starting position, the tongue 22 (FIGURE 6) of the leaf spring 18 slides over the abutment tongue 23 (FIGURES 2 and 5) of the frame 1, thereby raising the leaf spring 18 until its projection 19 is no longer in the recess 21 which, in turn, unlocks the ratchet lever 7. The ratchet lever 7 will then, under the influence of the spring 5, once again come to lie against the abutment 10. In the course of this movement of the actuating element, not only is the current supply to the heater winding 16 interrupted, but also, the bridging contact 25 is withdrawn from between the contact blades 26, 27.
The switch described in FIGURES 7 to 9 operates in a similar manner, except that the ratchet lever 7' is at right angles to the actuating element 3 and that the rest position of the abutment tongue 41 is adjustable with respect to the steps of the ratchet lever 7 by means of the set screw 43, 44.
It will be understood that the above description of the present invention is susceptible to various modiiications, changes and adaptations. For example, the number of steps 9 can be varied to meet the requirements of a particular switch, in that if it is desired to give the switch the capability of providing more than three different run-off periods, an appropriately higher number of steps and transverse contact strips on plate 24 will be provided.
1. A push-button type timing switch, comprising, in combination:
(a) a frame;
(b) an actuating element mounted for sliding movement on said frame;
(c) a ratchet lever coacting with said actuating element and having a plurality of steps;
(d) fixed abutment means on said frame and engaged by the side of one step of said ratchet lever and by the front of the subsequent step;
(e) spring means for urging said steps of said ratchet lever toward said fixed abutment means;
(f) movable abutment means arranged next to said iixed abutment means;
(g) bimetallic moving means connected to said movable abutment means for moving the same into and out of alignment with said ixed abutment means; and
(h) means connected to said bimetallic moving means for heating the same, whereby upon heating of said bimetallic moving means, the latter cause said movable abutment means to move out of alignment with said fixed abutment means thereby to raise said one step of said ratchet lever olf said fixed abutment means until, under the influence of said spring means acting on said ratchet lever, said front of said subsequent step comes into engagement with said movable abutment means, and after cessation of heating of said bimetallic moving means, the latter cause said movable abutment means to move back into alignment with said fixed abutment means, thus unblocking the previously engaged step and allowing said ratchet lever to move under the influence of said spring means so that the side of said subsequent step and the front of the next subsequent step of said ratchet lever come into engagement with said ixed abutment means, in consequence of which said ratchet lever, and with it said actuating element, are returned to a rest position under the inuence of said spring means in a half-step by half-step manner at a rate determined by the rate at which said bimetallic moving means are heated and allowed to cool.
2. A switch as defined in claim 1, wherein said ratchet lever is pivotally mounted on said actuating element.
3. A switch as delined in claim 2, wherein said ratchet lever is provided with a camming surface near the axis about which said ratchet lever pivots and said frame is provided with an abutment for engaging said camming surface and pivoting said ratchet lever against the action of said spring means beyond the position which said ratchet lever occupies in resty position, thereby to raise said steps off said abutment means and allowing said spring means to return said actuating element to its starting position.
ll. A switch as deiined in claim 3, further comprising locking means for locking said ratchet lever relative to said actuating element in the position into which said ratchet lever is moved upon engagement of said camming surface with said abutment, and for releasing said ratchet lever after said actuating element has returned to its starting position.
S. A switch as dened in claim 4, wherein said locking means comprise a leaf spring carried by said ratchet lever, said leaf spring having a projection which enters into a recess of said actuating element when said ratchet lever has been moved by the interaction between said camming surface and said abutment, thereby to hold said ratchet lever in such last-mentioned position, said leaf spring further having a releasing portion coacting with a further xed abutment on said frame when said actuating element is in said starting position which further fixed abutment raises said projection of said leaf spring out of said recess, thereby to allow said ratchet lever to return to its normal starting position with respect to said actuating element.
6. A switch as defined in claim 2, wherein said bimetallic moving means comprise a tirst bimetallicvstrip one end of which carries said movable abutmentmeans, a cross piece pivotally mounted onsaid frame and connected to the other end of said rst bimetallic strip, a second bimetallic strip having' one end connected to said cross piece, the other end of said second bimetallic strip being lixed, and wherein said means (h) comprise a heater winding for heating said second bimetallic strip.
7. A switch as dened in claim `6, further comprising adjusting means coacting with said other end of said se-cond bimetallic strip for regulating the starting position thereof and hence that of said movable abutment means.
8. A switch as dened in claim 2, wherein said bimetallic moving means -comprise a slide member carry.
in said means (h) comprise a heaterv winding'for heating one of said bimetalic strips.
9. A switch as defined in claim 8, wherein the other ends of said bimetallic strips are connected to a transversely displaceable member, thereby to allow the starting position of said movable abutment means to be regulated.
10. A switch as defined in claim 8, wherein said two bimetallic strips are arranged to bend in opposite directions when exposed to the same temperature change.
11. -A switch as defined in claim 2, further comprising a contact-carrying plate connected to said actuating element for movement therewith, movable contact means carried by said plate, and stationary contact means carried by said frame and coacting with said movable contact means.
12. A switch as dened in claim 11, wherein said means (h) comprise a heater, a plurality of spaced-apart contact strips arranged on said contact-carrying plate and extending transversely to the direction of movement thereof and a contact slide carried by said frame and coacting with said contact strips, said contact strips and contact slide together constituting a switch and being connected in series-circuit with said heater for turning the same on and off, one of said contact strips, upon initial actuation of said actuating element, being in electrical contact with said contact slide, thereby to turn on said heater and to cause the rst of said half-step movements of said ratchet lever and hence of said actuating element and plate, the spacing between consecutive contact strips being such that said contact slide is out of contact with any one of them in such half-step position of said plate,
thereby to turn said heater off and to allow said ratchet lever, and hence said actuating element and plate, to undergo the second of said half-step movements, thereby to make electrical contact between said contact slide and the next consecutive contact strip and once again to turn said heater on.
13. A switch as defined in claim 2 wherein said steps extend in the direction of movement of said actuating element and the number of heating and cooling cycles which said switch undergoes is dependent on the extentv to which said actuating element is initially depressed, whereby the switch may be actuated to produce any one of a plurality of diierent run-olf times.
References Cited UNITED STATES PATENTS 2,696,541 12/1954 Habermann 337-62 FOREIGN PATENTS 1,144,041 9/ 1952 France.
BERNARD A. GILHEANY, IPrimary Examiner R. L. COHRS, Assistant Examiner lU.S. Cl. X.R.