US2422097A - Electric switch - Google Patents

Description

June 10, 1947. K. H. HANSEN ELECTRIC swITCH Filed May 19, 1945 Patented June 10, 1947 ELECTRIC SWITCH Y Kenneth H. Hansen, White Plains, N. Y., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a

corporation oi Delaware Application'May 19, 1945, Serial No. 594,718

' (ci. zoo-159) 17 Claims. l

'I'his invention relates to improvements in electric switches, and more particularly to pushbutton switches of the shockproof type.

A primary object of the invention is to provide a novel and simplied form of shockproof pushbutton switch.

Another object is to minimize the number of additional parts required to render shockproof a` pushbutton switch of known form.

Another objectl is to obviate the necessity for use of latching mechanisms and/or relatively heavy springs in shockproof switches of this character.

Another and more specific object is to provide a push-button switch wherein two parts of substantially equal mass or so interlocked with respect to each other as to provide for simultaneous movement thereof only in opposite directions, so that any force (or shock) tending to move both in the same direction will result in locking the same to insure maintenance of their same relative positions.

Another object is to provide for shockproofness of a pushbutton switch in such a manner as to avoid any interference with the normal operation of the switch.

Another object is to provide a shockproof pushbutton switch the parts of which may readily be arranged to provide either thenormally closed type or the normally open type, or a switch having both normally closed and normally open contacts.

Another object is to provide a switch of the afore-mentioned character having butt-type contactors of novel form to afford a wear allowance and a wiping action.

Another object is to provide a shockproof pushbutton switch of the aforementioned character whereby the required operating force is greatly reduced without in anywise sacrificing any of the desirable shockproof characteristics thereof.

Another object is to provide novel means for balancing two long stroke members movable telescopically relatively to each other, whereby the space requirement of said parts jointly is minimized.

Another object is to provide such a pushbutton switch wherein shockproofness is insured regardless of the degree of wear of the contacts.

Another object is to provide a pushbutton switch having its parts arranged to insure maintenance thereof in their normal positions in the event of shock, whether the switch is of the normallyA closed type, or the normally lopen type, or of the normally closed and normally open type.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate apreferred embodiment of the invention, which will now be described, it being understood that the embodiment illustrated is susceptible of modication in respect of the structural details thereof within the scope of the appendedclaims.

In the drawings,

Figure 1 is a top plan view, actual size, of a shockpro'of pushbutton switch constructed in accordance with my invention.

Fig. 2 is a vertical sectional view, on the line 2-2 of Fig. 1.

Fig. 3 is a vertical sectional view, on the line 3-3 of Fig. 1.

Fig. 4 is a vertical sectional view, on the line 4--4 of Fig. 1, with the pushbutton depressed to effect opening of the normally closed contacts and closure of the normally open contacts.

Fig. 5 is an enlarged developed and somewhat diagrammatic view of the three cooperating parts shown in various other figures of the drawings,

whereby shockproofness of the switch is insured.

Fig. 6 is a side elevational view, in separated relation, of the three elements shown in Fig. 5; the contact-.ors being omitted from the carrier in Fig. 6 to better illustrate the means for effecting an operative and interlocking connection between said parts, and

Fig. 'Z is a top plan view of the carrier, with the upper and lower contactors attached thereto.

Heretofore it has been proposed to provide 'for shockproofness of pushbutton switches by the use of manually operable latching devicesand/or the use of very heavy return springs. The use of manually operable latching devices is obviously undesirable, especially where operation of such a. device is required to maintain the switch in its normal position; whereas if a very heavy spring is employed to maintain the switch in its normal position, such aspring not only fails to insure shockproofness under all conditions, but it also greatly increases the manual force required to operate the switch, with obvious disadvantages.

In accordance with my invention, however, the pushbutton switch is made shockproof under all conditions without the necessity for use of a manually operable latch or latches; and the switch only requiring a return spring of sufliclent strength to aord the desired pressure of the contactor against one set of stationary contacts in the normal position of-the switch.

' I have shown my invention as applied, by Way of example, to a pushbutton switch of the character disclosed in Patent No. 1,889,175. lanted November 29, 1932 to C. T. Evans.

In the drawings, the numeral I designates a one-piece molded base, composed of a suitable insulating material such as Bakelite, adapted to be produced by a straight-line molding operation; said base having thereon an integral upward projection which is recessed at I2 to provide clearance for reciprocation of a manually operable pushbutton I3 which is molded to the form shown from a suitable insulating material such as Bakelite Button I3 is preferably provided at its lower end with a diametrically opposed pair of integral lugs I3* and I3 which have a fairly close sliding fit between the side walls of a pair of auxiliary recesses I2* and I2h (Figs. 1 and 2); portions at least of said lugs being at all times positioned within said auxiliary recesses to positively prevent any Substantial degree of rotation of pushbutton I3 with respect to base I0.

Pushbutton I3 is provided in its lower end with a relatively large substantially cylindrical central recess |3, and a centrally located cylindrical recess I3d which opens to the upper end wall of recess I3. Recess I3d has a thread I3e (Fig. 2). formed therein by tapping or in any other suitable manner. i

A tubular metal member I4 has a reduced andV externally threaded upper end portion I4', which is adapted to take into the aforementioned threaded recess in button I3; member I4 having a shoulder |4b (Fig. 2) formed thereon, and a split lockwasher I5 being interposed between said shoulder and the upper end wall of recess |3 to lock member I4 against rotation with respect to pushbutton I3 upon proper assembly of said parts. When parts I3 and I4 have been thus assembled a relatively small hole is drilled diametrically through member I4 a predetermined short distance above the lower end thereof; the axis of 4o said hole (as indicated in Fig. 2) preferably extending at right angles to the central plane of the lugs I3*i and |3b; and a pin I4 being assembled with a press ilt into said hole in such a manner that equal end portions of said pin (say, onesixteenth of an inch) project from diametrically opposite sides of member' I4, as best illustrated in Fig. 6.

A ilat punched sheet metal plate I3 is adapted to seat against and substantially cover the bottom wall of recess I2; said plate having reduced end portions i6'- and I6b adaptedv to overlie the bottom walls of auxiliary recesses I2* and I2. Said portions I 6 and I6 have tapped openings formed therein to accommodate the respective threaded Shanks of a pair of bolts or screws I`I,` Il, which penetrate passages III'l and |01 (Fig. 2) formed in base I0. The heads of screws I1 preferably flt into correspondingly shaped countersinks in the lower surface of an elongated rectangular metal strip or. plate I3 whose opposite end portions seat against ledges offset upwardly a substantial distance from the lower surface of base I0.

Plate I8 is provided centrally thereof with an 65 opening I8l the lower end of which is flared as shown at I8b in Figs. 2, 3 and 4. A disk-like metal bearing member I9 is seated upon the upper surface of plate I8 and has an integral shank I3* whose lower end is upset or riveted into countertubular metal member 20, to assist in centering 4 the latter, member 20 being adapted to rotatably bear at its upper end against the lower surface of plate I3 and at its lower end against the upper surface of member I3.

Extending downwardly from the upper end of member 20 are a pair of diametrically opposed slots; said slots preferably extending vertically downwardly for a portion oftheir length, as best illustrated at 20* and 20h in Fig. 5; said slots then extending at a predetermined angle (preferably toward the right at an angle of 45 degrees, as illustrated) to points a substantial distance` above the lower end of member 20; said angled portions of the slots being designated by numerals 20 and 20d, respectively.

Slots 20, 20 and 2lb, 2||d are adapted to slidably accommodate the aforementioned projecting ends of pin I4; the arrangement preferably being such that in the finally assembled normal positions of the parts' the projecting ends of pin |4c will be located slightly below the vertical portions 20n and 20", and within the portions 20 and 20i of said slots (see Figs. 3 and 5). The wall thickness of member 20 is preferably at least one-sixteenth of an' inch, to insure against projection of the respective ends of pin |4 beyond the periphery thereof. It is to be understood, of course, that if member 20 is made of greater or lesser wall thickness the length of pin |4 may be correspondingly varied.

Member 20 has rigidly attached thereto and projecting outwardly from diametrically opposite and alined points on the periphery thereof a pair of studs or pins 2| and 22; said studs, as indicated in dotted lines in Fig. 6, having integral Shanks which penetrate corresponding holes in the peripheral wall of said member and are upset over the countersunk inner ends of the respective holes in a flush relationship to the inner periphery of said wall. Other suitable means may, of course, be employed for affording rigid and proper attachment of studs 2| and 22 to member 20, as, for instance, by providing a suitable welded or screw-threaded attachment of the former to the latter.

The studs 2| and 22 are adapted to jointly register with a pair of diametrically opposed slots 23n and 23b extending upwardly toward the right (at an angle of 45 degrees, to correspond with the angle of slot portions 23 and 2lid aforementioned) from the lower tubular end portion 23c of a metal contactor-carrier member, designated in general by the numeral 23. Slots 23l and 23h extend upwardly to corresponding points adjacent but below the upper end of the upper integral tubular end portion 23d of member 23. Member 23 is preferably a casting, in which the slots 23 and 23b may be formed by milling or cutting, or in any other suitable manner. Member 23 is provided in a plane spaced a suitable distance above the lower end thereof with an integral flange or peripheral projection, the contour `of which is best illustrated in Fig. 6. Thus said flange comprises an annular portion 23, and four substantially rectangular portions 231, 23|, 235 and 23i equally spaced from each other around the periphery of portion 23.

Like bridging contactors 24 are vpositioned upon the respective upper and lower surfaces of flange 23; each contactor preferably comprising an annular punching of a suitable highly conductive and resilient sheet metal, such as phosphor bronze, and each annulus having a pair of diametrically opposed substantially rectangular projections 24 and 24. Each contactor 24 is initially of bent or bowed form in transverse cross section so that the extensions 24l and 24b of the upper contactor are biased away from the upper surfaces of projections 23i and 23?, whereas the corresponding extensions 54 and 24b of the lower contactor are biased away from the lower surfaces of projections 23I and 23h.

The outer surfaces of extensions 24a and 24b of each contactor have welded, brazed, or otherwise rigidly attached thereto the tips 24c composed of silver 0r a suitable silver-base composition. The annular portion of each contactor 24 is provided with a diametrlcally .opposed pair of openings (not shown) in equally spaced relationship to extensions 24n and 24", which openings are alined with a corresponding pair of openings in fiange 23e to accommodate the shanks of a pair of headed rivets 25, 25, the Shanks of which pairs are respectively upset over opposite faces of flange 23e to rigidly secure said contactors to said carrier. As indicated in dotted lines in Fig. 7 and in full lines in Figs. 3 and 4, the contactors 24 are arranged in reversely facing relationship on opposite surfaces of flange 23e and are displaced at a rotary angle of 90 degrees with respect to each other. In this manner the lower contactor 24 is adapted to move into bridging engagement with an upwardly facing lower pair of stationary contacts 26, 26 (Fig. 3) in the lower extreme position of carrier 23; whereas the upper contactor 24 is adapted to move into bridging engagement with a downwardly facing -pair of stationary contacts 26, 26 (Fig. 4) when carrier 23 is lmoved to its upper extreme position.

Base III is recessed in its lower surfacein the manner illustrated in- Figs. 2, 3 and 4; it being noted that the four auxiliary recesses Hic, Ille, I Ild and I 0f are of such form as to provide for l axial reciprdcation of carrier 23, but of such width as to cooperate with the end portions of extensions 23f, 238, 23h and 231, respectively, to positively prevent rotation of said carrier.

The aforementioned stationary contacts 26 are of bimetallic or laminated form; a relatively thin layer 2,6i thereof preferably being composed of silver, and the remainder thereof preferably consisting of copper. As shown, said pairs of stationary contacts are so positioned within base I0 that the silver layers 26a are adapted for engagement by the silver tips 24c of the respectivo upper and lower contactors.

The stationary contacts 26 of the lower pair are adapted to seat against downwardly facing ledges IIJ and I0h formed in auxiliary recesses Illl and IllI which are arranged at the same radial angles as the aforementioned auxiliary recesses II)c and Ind, respectively; said contacts having openings (not shown) alined with passages luk and |01 formed in lbase I Il to accommodate the shanks of securing bolts, the heads of which are designated by numerals 21, 21 in Fig. 3; suitable lockwashers being preferably interposed between said heads andcontacts 26. The threaded upper ends 21 of said bolts each have a lower nut 28 threaded thereon to secure the respective contacts 26 in fixed position, and each also is provided with an additional nutl 28 to provide for clamping of a circuit wire; said bolts 21 being located at diagonally opposite corners of base Ill, as shown in Fig. 1. As shown in Figs. l, 3 and 4 the lower nut 28 of each pair' is adapted to fit snugly within a recess of similar contour to lock such nut against rotation with respect to base I0.

The stationary contacts 26 of the upper pair are respectivelypositioned upon downwardly facing ledges Im and I0, lwhich ledges form downward offsets of portions of the respective end walls of auxiliary recesses IIle and IIIf (Fig. 4). The contacts of said pair are positioned with their silver layers 26 facing downwardly, and relatively short bolts, the heads of which are shown at 29, 29 have their shanks penetrating split lockwashers, the openings in the respective upper contacts 26 and passages |00, II!p formed in base I 0; the threaded shank end of each bolt being adapted for cooperation with a pair of nuts 28 like those aforedescribed. It will be apparent that rivets of suitable length might be substituted for the aforementioned pairs of bolts 21 and 29, and that other forms of terminal wire attaching means might be employed.

As shown in Figs. 3 and 4, the aforementioned plate I6 is provided with a central circular opening I6c of a size to provide slidable clearance for the tubular member I4; and as shown in Fig. 3 said plate is also provided with a pair of alined rectangular slots or notches I6d and I6e com municating with opening I 6. Notches I6d and I6 are adapted to provide for initial downward insertion of member i4 through plate I6 only when the pin I4c is in a given rotary or angular position, to facilitate assembly of the switch parts.

As shown, base ID is provided with a central circular opening Il)q to afford rotary clearance for the upper end portion of member 20; and base III is provided below said opening IIIq with a cylindrical recess I0r to insure adequate reciprocating clearance for carrier 23 when moved to its upper extreme position, as best illustrated in Fig. 4.

A coiled compression spring 30 is interposed between the upper surface of plate I6 and the split lockwasher at the end wall of recess 63C;

said spring preferably being of sufficient caliber` or strength to insure the desired degree of pres sure of the lower contactor 24 against the lower set of stationary contacts 26 in the normal relative positions of the various switch parts. As aforeindicated, the pushbutton I3 and the parts attached thereto (that is to say, member I4, the lockwasher and pin |40) preferably have the same mass as the aforementioned carrier 23 and the parts (contactors 24 and their fastening means) attached thereto. Because these two reciprocating parts of the switch are thus balanced with respect to each other, it is obvious that a spring 30 affording a suitable degree of contact pressure in the normal positions of the switch parts will likewise insure the desired bias of said switch parts to said normal positions thereof. It is to be understood, of course, that a spring corresponding to that shown at 30, but of any desired greater degree of strength may be employed; but such a change involves the undesirable feature that the degree of force required to depress pushbutton I3 to its lower extreme position will be correspondingly increased.

From the foregoing description it will be apparentthat the pushbutton I3 and its attached parts a're free to reciprocate, but are positively restrained against rotation. The same is true of the carrier member 23 and the contactors 24 attached thereto. On the other hand, the tubular member 20 is permitted torotate, under given conditions, relatively to base I0, but is restrained by its associated bearing plates I6 and I8 against yany substantial degree of axial movement with amaca? upper set of stationary contacts 26 may be positioned upon the ledges |01 and I0, preferably with base inverted, and attached thereto by bolts 29 and their associated parts, as best illustrated in Fig. 4. As a sub-assembly, with tubular member Il attached to pushbutton I3 as aforedescribed, and with pin Il attached to said tubular member, coiled spring 30 is strung upon member I0 and compressed so that one side of the lower coil thereof will seat upon one end of pin I4. Member Il is then inserted through opening I6c in plate I6 (see Fig. 4) at such arotary angle that the ends of pin I4 will pass through notches iSd and I6. thus slightly further compressing spring 30. Thereafter the pushbutton and member I4 may be rotated to bring the ends of pin I4c out of alinement with notches I6d and |6. to temporarily latch said parts against displacement relatively to each other.

Said sub-assembly is then inserted downwardly f into recess I2 (Fig. 4) so that plate I6 is seated against the lower wall thereof.

As a second sub-assembly the tubular member 20 is inserted upwardly through the tubular portions 23c and 23d of contactor-carrying member 23 (with the upper and lower contactors 24 attached thereto as shown in Fig. 7); with either stud 2| or 22 iitting into cam-slot 23 (Fig. 6) and the other stud iitting into the other camslot 23b (Fig. 5). Pushbutton I3 is then fully depressed so that the straight portions 20n and 2|)b of the slots in member 20 are 'alined with either of the respective ends of pin Hc, and said last mentioned sub-assembly is pressed upwardly until the ends of pin Hc have entered the cam portions 20c and 20d of said slots; the aforementioned extensions 23f, 231, 2lih and 23l entering auxiliary recesses I0, I0, I 0d and |01, respectively. Then upon manual release of pushbutton I3 and said last mentioned sub-assembly the member 23 will move downwardly until the studs 2| and 22 are stopped by the upper ends of slots 23a, 23h, whereas the ends of pin HC will still be within the cam portions 20 and '4.0i of the slots in member 20, to temporarily retain all of said parts in assembled relationship to each other and to base I0.

Thereafter the 'stationary contacts 26 of the lower set are positioned upon the respective ledges I0g and I 0h (with base I0 preferably inverted) and the bolts 2l and their associated parts are then applied to rigidly attach said contacts to base I0, in the manner indicated in Fig. 3.

Thereafter plate I8 is positioned against the upwardly oilset ledges in the lower surface of base I0, as shown in Figs. 2, 3 and 4. An inverted channel-shaped member 3| Yof fiber or similar insulating material is preferably interposed between plate I8 and base |0 to insure proper insulation of said plate from the lower contacts 26. Plate I8 is then rigidly attached to base I0 by threading of bolts I'I into the aforementioned end portions of plate I8 (Fig. 2). Upon attachment of plate I8 the portion I8c enters the lower end of member 20 and the aforementioned disk-like portion of member I9 engages the lower edge of member 20 to act as one of the end bearings therefor; so that the various parts will assume their normal positions shown in Fig. 3. Insulating member 3| is provided with a central opening to accommodate disk` I9, and withV openings (Fig. 2) to provide clearance for bolts I1. As shown in Fig. 1, base |0 is provided on two opposite sides thereof with downwardly oiiset perforated ledges II)s and Il)t to accommodate the shanks of securing bolts or screws (not shown) whereby the switch may be attached as a whole to a panel or other suitable support.

As will be apparent to those skilled in the art. the upper set of stationary contacts 26 and the circuit wire connecting terminals thereof may be omitted, whereby a normally closed and momentarily open switch is provided. In practice, however, I prefer to employ the upper set of contacts 26 under such conditions, to act as dummies for limiting the upward movement oi carrier 23, the additional wire clamping nut 28 associated with each bolt 2i)a being unnecessary. Similarly, with only the upper set of contacts 26 connected in circuit, a. normally open and momentarily closed pushbutton switch may be provided. the additional nut 28 associated with each bolt 21 being unnecessary. That is to say, a circuit will be closed as long as pushbutton I3 is held in its fully depressed position (shown in Fig. 4).

I have herein illustrated a pushbutton Il which is normally biased to its upper extreme position (Fig. 3) and is manually movable to its opposite extreme position (Fig. 4) but it is to be understoodthat by slightly modifying the form of the pushbutton to provide cam-operable elements (like those shown at 32c and 32d in Fig. 5 of Patent No. 2,357,971, granted Sept. 12, 1944, to C. F. Robbins) the same may be indirectly operable manually by a selector cam-ring like that shown at 35 in Fig. 8, or that shown at I6 in Fig. 1o. of'said Patent No. 2,357,971. The switch hereof with such a modied form of pushbutton might also be employed with operating and latching elements of the character disclosed in Patent No. 2,370,877, granted March 6, 1945, to C. F. Robbins; it being understood that the shockprooi characteristics of the switch herein disclosed will not be in anywise affected by such modifications.

Moreover, it is to be understood that the specic form and arrangement of shockprooilng elements herein disclosed are not essential, so long as the operating elements (pushbutton) and its associated parts are balanced by (or of substantially equal weight with respect to) the carrier member and the contactor or contactors attached thereto, with suitable means interposed between said parts to insure against simultaneous movement thereof in a like direction.

After the switch parts have been assembled as afore-described, and assuming normal positioning of said parts, as shown in1 Figs. 2, 3 and 5, through the bias afforded by coiled compression spring 30, the lower bridging contractor 2l will have its contact tips 24 (see Fig. 3) engaged with the lower pair of stationary contacts 28, 28; thus providing for completion ci' a circuit whose terminal wires (not shown) may be clamped between the respective pairs of nuts upon the shanks 21" 21 of bolts 21, 21.

Upon manual depression of pushbutton I3 from the normal position thereof shown in Fig. 3 to the lower extreme position thereof shown in Fig. 4, the consequent downward but non-rotating movement of tubular metal member I 4 will, through the projecting ends of pin I, act upon the lower side walls of the angled slots 20 and 20d to eil'ect clockwise rotation of the tubular metal member (see Fig. 6); the latter being restrained, as aforedescribed, against any substantial degree of vertical movement in either direction. As best illustrated in Fig. 5, such rotation of described. As an incident to depression of pushl button I3 member 23 will be lifted until the tips 24 of the upper bridging contactor 24 are engaged with the upper pair of stationary contacts 2B, 26, as shown in Fig. 4; the coiled compression spring acting to return the several switch parts to their normal positions shown in Fig. 3 upon release of pushbutton I3.

As aforedescribed because the pushbutton I3 and the parts attached thereto are of substantially the same weight as the member 24 and the parts attached to the latter, whereas said pushbutton I3 and member 23 are constrained when moved to move jointly but only in opposite directions with respect to eachy other; it follows that such arrangement and relationship of said members in- Asures shockproofness of the switch mechanism as a whole under all conditions. vFor example it is obvious from Fig. 4 thatin the event of an impact, or shock or vibration tending to effect inward movement of pushbutton I3, the same force will act in the same direction upon member 23 to effectively lock said parts against movement relatively to each other.

As will be apparent to those skilled in the art,

,a similar result might be obtained by omitting one projecting end of pin I4c and the slot 20 or 2l)d respectively cooperating therewith. Similarly one or the other of the pins 2| or 22 and its resaid operating member and also movable in a substantially straight line between opposite extreme positions into vand out of engagement with said contact means, said operating member and said contactor being of substantially equal mass, and means including an interposed rotatable tubular member affording a positive driving connection between said operating member and said contactor, said last mentioned means being adapted to insure against simultaneous movement of said operating member and said contactor in a like direction.

2. In a, shockproof electric switch, in combination, stationary contact means, an operating member movable in a substantially straight line between extreme positions, a contactor slidably mounted concentrically with respect to said operating member and also movable in a substantially straight line between opposite extreme positions into and out of engagement with said contact means, said operating member and said contactor being of substantially equal mass, and means including an interposed rotatable tubular member aitording a driving connection between said operating member and said contactor, said last mentioned means being adapted to insure against simultaneous movement of said operating member and said contactor in a like direction under normal operating conditions or in the event of shock. 1

3. In a shockproof electric pushbutton switch, in combination, an insulating, base, stationary kcontact means carried by said base, an operating pushbuttony member mounted on said base and movable with respect thereto in a substantially straight linel between extreme positions, a contactor arranged concentricallywith respect to said operating pushbutton member and movable telescopically with respect to the latter between oppostie extreme positions into and out of engagementwith said contact means, said operating pushbutton member and said contactor being of substantially equal mass, means including an interposed rotatable tubular member having driving connections with said operating pushbutton member. and said contactor. said driving connections 4. In a shockproof electric switch, in combination, a manual operating member movable forth and back between opposite extreme positions, stationary contact means, a contactor surrounding said operating member and slidably movable with v respect thereto forth and back between opposite extreme positions into and out of engagement with said contact means, means including a rotatable tubular member affording a positive driving connection between said operating member and said contactor, said driving connection being of such character as to insure against simultaneous movement o f said operating member and the contact engaging portion of said contactor in a like direction, spring means to bias said operating member and contactor to one of their respective extreme positions, and said operating member and contactor having .portions of substantially equal mass arranged in counterbalanced relationship to each other, whereby said switch is rendered shockproof with respect to rotative or straight line motions, or both.

5. In a shockproof electric switch, in combination, an operating member mov-able in a substantially straight line between opposite extreme positions, stationary contact means, a contactor slidably surrounding said operating member and also movable in a substantially straight line between opposite extreme positions into and out of engagement with said contact means, said operating member and said contactor being of substantially equal mass, means including an interposed tubular member affording a driving connection between said operating member and said contactor, said last mentioned means being adapted to insure against simultaneous movement of said operating member and said contactor in a like direction, and spring means to bias said operating member to one of its extreme positions.

6. In a shockproof electric switch, in combination, an operating member movable in a straight line between opposite extreme positions, stationary contact means, a contactor slidably surrounding said operating member and also movable in a straight line between opposite extreme positions into and out of engagement with said contact means, said operating member and said contactor being of substantially equal mass, means including a. tubular member surrounding said operating member and surrounded by saidcontactor affording a driving connection between said operating member and said contactor, said last mentioned means being adapted to insure against simultaneous movement of said operating member and said r 11 contacter in a like direction, and spring means to normally bias said operating member to one of its extreme positions whereby engagement of said contaetor with at least a portion of said stationary contact means is eiiected, said spring means being only of such strength as to aiIord the desired pressure of said contacter against .thestationary contact means with which it is engaged, whereby the operating force required to move said operating member out of said normal position vthereof is minimized.

7. In an electric switch, a reciprocatable operating member, a reciprocatable bridging contactor slidably surrounding each operating member, means including a rotatable tubular member interposed between and positively interconnected with said operating member and said contactor to insure simultaneous movement of the former and the latter in opposite directions respectively according to the direction of movement of said operating member, and spring means associated with said operating member to normally bias the same to one of its extreme positions, said operating member and said contacter being of substantially equal mass to provide for shockproofness thereof under all conditions.

8. A shockproof electric switch comprising an insulating base, a set of spaced stationary contacts positioned upon said base, a contactor reciprocatable into and out of bridging engagement with said contacts, an operating member reciprocatable within said contactor, a rotatable member y interposed between said contactar and said operating member, said rotatable member having associated means to positively restrain the same against reciprocating movement, said operating member having a positive driving connection with said rotatable member and the latter having a positive driving connection with said contactor, said driving connections being of such character that movement of said operating member in one direction is adapted to insure a corresponding degree of simultaneous movement oi' said contactor in the opposite direction,-said operating member and said contacter being of substantially equal mass whereby the same are locked by said driving connections against simultaneous movement in a like direction in the event of a shock, and spring means associated with said operating member to bias the same to one of its extreme positions.

9. A shockproof electric switch comprising an insulating base, two sets of spaced stationary contacts positioned upon said base, a reciprocatable carrier member, a pair of contactors attached to said member and jointly movable thereby into and out of engagement with said sets of contacts selectively, an operating member reciprocatable within said carrier'member, a rotatable tubular member interposed between said carrier and operating members, said rotatable member having associated means to positively restrain the same against reciprocating movement, said operating member having a positive driving connection with said rotatable member and the latter having a positive driving connection with said carrier member, said driving connections being of such character that movement of said operating member in one direction is adapted to insure a corresponding degree of simultaneous movement oi' said carrier member in the opposite direction, said operating member being of substantially the same mass as said carrier member and said contactors jointly whereby said reciprocatable members are I l2 taneous movement in alike direction in the event of a shock. and a coiled compression spring interposed between said base and a part of said operating member to bias the latter to one of its extreme positions.

10. A shockproof electric switch comprising an insulating base, two sets oi' spaced stationary contacts, positioned upon said base, a reciprocatable carrier member, a pair of contactors attached to said member and jointly movable thereby into and out o! engagement with said sets of contacts selectively, an operating member reciprocatable within said carrier member, a rotatable tubular member interposed between said other members, said rotatable member having associated means to positively restrain the same against reciprocating movement, said operating member having a positive driving connection with said rotatable memy ber and the latter having a positive driving connection with said carrier member, said driving connections being oi such character that movement of said operating member in one direction is adapted to insure a corresponding degree of simultaneous movement of said carrier member in the opposite direction, said operating member being of substantially the same mass as said carrier member and said contactors jointly whereby said reciprocatable members are locked by said driving connections against simultaneous movement in a like direction in the event ot a shock, a coiled compression spring interposed between said base and a part of said operating member to bias the latter to one of its extreme positions, and said spring being of just sufficient strength to afford the desired pressure of one of said contactors against its cooperating set of contacts in the normal position of the switch parts, whereby the manual force required to eilect movement of said operating mem-ber to its opposite extreme position is minimized.

i1. A shockproof electric switch comprising an insulating base, two sets of spaced stationary contacts positioned upon said base, a reciprocatable carrier member, a pair of contactors attached to said member and jointly movable thereby into and out of engagement with said setsof contacts selectively, a reciprocatable operating member, a rotatable tubular member surrounding said operating member and surrounded by said carrier member, said rotatable member having associated means to positively restrain the same against reciprocating movement, said operating member having a positive driving connection with said rotatable member and the latter having a positive driving connection with said carrier member, said driving connections being of such character that movement of said operating member in one direction is adapted to insure a corresponding degree of simultaneous movement of said carrier member in the opposite direction, said operating member being .of substantially the same mass as said carrier member and said contactors jointly whereby said reciprocatable members are locked by said driving connections against simultaneous movement in a like direction in the event of a shock, a coiled compression spring interposed between said base and a part of said operating member to bias the latter to one of its extreme positions. said spring being of just suiilcient strength to afford the desired. pressure of one of said contactors against its cooperating set of contacts in the normai position of the switch parts, whereby the manual i'orce required to eii'ect movement ot said operating member .to its opposite extreme position locked by said driving connections against simulis minimized, and each of said driving connectiom 13 1 comprising a pair of diametrically opposed projecting studs on one of said members and a pair of diametrically opposed angularly extending slots on another of said members for cooperation with said studs.

12. In a shockprooi electric switch, in combination, an operating plunger of circular form in 'transverse cross section, a tubular metal cylinder within which said plunger is adapted to slide, a pair of xed bearing members at opposite ends of said cylinder to permit rotation while preventing endwise displacement thereof, a second tubular member surrounding said first tubular member and slidably movable with respect thereto, said plunger and said first tubular member having a pin and cam-slot connection to provide for rotation of said first tubular member in opposite directions respectively according to the direction of reciprocating movement of said plunger, said first tubular member and said second tubular member having a pin and cam-slot connection to provide for reciprocating movement of said second tubular member in a reverse direction to said plunger as an incident to rotation of said iirst tubular member, a set of stationary contacts, a contactor carried 4by said second tubular member and movable into and out of engagement with said stationary contacts as an incident to movement of said plunger to its opposite extreme positions, and spring means associated with said plunger to normally bias the same to one of said extreme positions thereof.

13. In a shockproof electric switch, in combination, an operating plunger of circular form in transverse cross section, a tubular metal cylin.- der within which said plunger is adapted to slide, a pair of fixed bearing members at opposite ends of said cylinder to permit rotation while preventing endwise displacement thereof, a second tubular member surrounding said first tubular member and slidably movable with respect thereto, said plunger and said first tubular member having a pin and cam-slot connection to provide for rotation of said first tubular member in opposite directions respectively according to the direction of reciprocating movement of said plunger, said first tubular member and said second tubular member having a pin and cam-slot connection to provide for vreciprocating movement of said second tubular member in a reverse direction to saidplunger as an incident to rotation of said rst tubular member, a set of stationary contacts, a contactor carried by said second tu bular member and movable into and out of engagement with said stationary contacts as an incident to movement of said plunger to its opposite extreme positions, spring means associmass of said plunger and parts carried thereby substantially corresponding to the mass of said second tubular member and said contactor, to thereby stabilize and lock said parts against re1- ative movement in any given position thereof.

14. In a shockproof electric switch, in combination, an operating plunger of circular form in transverse cross section, a tubular metal cylinder within which said plunger is adapted to slide, a

pair of fixed bearing members at opposite ends of said cylinder to permit rotation while preventing endwise displacement thereof, a second tubular member surrounding said ilrst tubular member and slidably movable with respect thereto, said plunger and said rst tubular member having a pin and cam-slot connection to provide cured to said base in spaced relationship to each for rotation of said first tubular member in ol)` posite directions respectively according to the direction of reciprocating movement of said plunger, said first tubular member and said second tubular member having a pin and cam-slot connection to provide for reciprocating movement of said second tubularmember in a reverse direction to said plunger as an incident to rotation of said first tubular member, a. set of stationary contacts, a contacter carried by said second tubular member and movableinto and out of engagement with said stationary contacts as an incident to movement of said plunger to its opposite extreme positions, spring means associated with said plunger to normally bias the same to one of said extreme positions thereof, the mass of said plunger and parts carried thereby substantially corresponding to the mass of said second tubular member and said contactor, to thereby stabilize and lock said parts against relative movement in any given position thereof, and one of the parts carried by said plunger comprising a manually operable pushbuttoniswitch. v

15. In a shockproof electric switch, in combination, a recessed molded insulating base, upper and lower sets of stationary contacts secured to said base within said recess, said base having a second recess formed therein, a molded insulating pushbutton non-rotatably slidable within said second recess, said pushbutton having. a metal member of circular cross section non-rotatably attached thereto and adapted to project into said rst recess, saidl metal member having studs rigidly attachedl thereto and projecting from diametrically opposite points adjacent the lower end thereof, a pair of metal abutment members secther, a tubular metal member interposed endwise between said abutment members and restrained thereby against endwise movement but rotatable with respect thereto, said tubular metal member having a pair of diametrically opposed slots formed therein and opening to the upper end thereof, like portions of said slots extending in a like direction. at a` predetermined angle toward the lower end of said tubular metal member for cooperation with said studs, said tubular metal member also having studs rigidly attached thereto and projecting from diametrically opposite points thereof, a second tubular member having a pair of diametrically opposed slots formed therein and opening to the lower end thereof, likey portions of said last mentioned slots extending in a like direction at a predetermined angle toward the upper end of said second tubular member for cooperation with said second mentioned studs, said last mentioned angle being of like ated with said plunger to normally bias the same to one of said extreme positions thereof, and the' value but opposite in direction with respect to said angle4 first mentioned, said second tubular member having an upwardly facing bridging contactor and a downwardly facing bridging contactor attached thereto for cooperation with the respective sets of contacts in the selective opposite extreme positions of said member, a coiled spring interposed under a predetermined degree of compression between said base and said pushbutton whereby the movable switch parts are normally biased to given extreme positions thereof, and said pushbutton and the parts carried thereby being of substantially the same mass asv said second tubular member and said contactors, whereby all of said movable switch parts are locked against relative movement in the event of shock when the same are in their respective normal positions.

, 15 16. In a shockproof electric switch, in combination, a recessed molded insulating base, upper and lowerl sets of stationary contacts secured to said base within said recess, said base having a second recess formed therein, a molded insulating pushbutton non-rotatably slidable within said second recess, said pushbutton having a metal member of circular cross section non-rotatably attached thereto and adapted to project into said first recess, said metal member having studs rigidly attached thereto and projecting from diametrically opposite points adjacent the lower end thereof, a pair of metal abutment members secured to said base in spaced relationship to each other, a tubular metal member interposed endwise between said abutment members and restrained thereby against endwise movement but rotatable with respect thereto, said tubular metal member having a pair of diametrically opposed slots formed therein and opening to the upper end thereof, like portions of said slots extending in a like direction at a predetermined angle toward the lower end of said tubular metal member for cooperation with said studs, said tubular metal member also having studs rigidly attached thereto and projecting from diametrically opposite points thereof, a second tubular member having a pair of diametrically opposed slots formed therein and opening to the lower end thereof, like portions of said last mentioned slots extending in a like direction at a predetermined angle toward the upper end of said second tubular member for cooperation with said second mentioned studs, said last mentioned angle being of like value but opposite in direction with respect to said angle iirst mentioned, said second tubular member having an upwardly facing bridging contactor and a downwardly facing bridging contactor attached thereto for cooperation with the respective sets of contacts in the l. selective opposite extreme positions of said member, a coiled spring interposed under a predetermined degree of compression between said base and said pushbutton whereby the movable switch parts are normally biased to given extreme positions thereof, and said pushbutton and the parts carried thereby being of substantially the same mass as said second tubular member and said contactors, whereby all of said movable switch parts are locked against relative movement in the event of shock when the same are in their extreme positions or in any of their intermediate positions.

17. In a shockproof electric switch. in combination, a recessed molded insulating base, upper and lower sets of stationary contacts secured to said base within said recess, said base having a second recess formed therein, a molded insulating pushbutton non-rotatably slidable within said second recess, said pushbutton having a metal member of circular cross section non-rotatably attached thereto and adapted to project into said rst recess, said metal member having studs rigidly attached thereto and projecting from diametrically opposite points adjacent the lower end thereof, a pair of metal abutment members secured to said base in spaced relationship to each other, a tubular metal member interposed endwise between said abutment members and restrained thereby against endwise movement but rotatable with respect thereto, said tubular metal member having a pair of diametrically opposed slots formed therein and opening to the upper end thereof, like portions of said slots extending in a like direction at a predetermined angle toward the lower end oi said tubular metal member for cooperation with said studs, said tubular metal member also having studs rigidly attached thereto and projecting from diametrically opposite points thereof, a second tubular member having a pair of diametrically opposed slots formed therein and opening to the lower end thereof, like portions of said last mentioned slots extending in a like direction at a predetermined angle toward the upper end of said second tubular member for cooperation with said second mentioned studs, said last mentioned angle being of like value but opposite in direction with respect to said angle irst mentioned, said second tubular member having an upwardly lacing bridging contactor and a downwardly facing bridging contactor attached thereto for cooperation with the respective sets of contacts in the selective opposite extreme positions of said member, a coiled spring interposed under a predetermined degree of compression between -said base and said pushbutton whereby the movable switch parts are normally biased to given extreme positions thereof, said pushbutton and the parts carried thereby being of substantially the same mass as said second tubular member and said contactors, whereby all of said movable switch parts are locked against relative movement in the event of shock when the same are in their extreme positions or in any of their intermediate positions, and each of said contactors including resilient portions whereby 'shockproofness of said switch is insured regardless of the degree of wear of said contacts and said contactors.

KENNETH H. HANSEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITFDl STATES PATENTS Number Name Date 1,162,735 Ely Nov. 30, 1915 1,257,287 Kaisling Feb. 19, 1918

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