US2367441A

US2367441A - Sealed switch

Info

Publication number: US2367441A
Application number: US405589A
Authority: US
Inventors: Frank W Schwinn
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-08-06
Filing date: 1941-08-06
Publication date: 1945-01-16
Anticipated expiration: 1962-01-16

Description

Jan. 16, 194,5. F. w. scHwlNN 2,367,441 i SEALED SWITCH Filed Aug. 6. 1941 3 Sheets-Sheet 1 dafzy/@Jhz' @/m/law,

` @Wega Jan. 16, 1945.

F. w. scHwlNN l SEALED SWITCH Filed Aug. 6, 1941 3 Sheets-Sheet 3 Patented Jan. 16, 1945 y PATE-NT oFFicEf SEALED SWITCH Frank W. Schwinn, Chicago, Ill.

Application August 6, 1941, Serial No. 405,589

' 4 Claims.

This invention `relates to improvements in weatherproof or sealed electrical switches, and

more particularly concerns a switch having the contacts supported by and sealed within a hollow resilient body which is compressible to actuate the contacts.

There has been a long-felt need for a practical, low cost simple switch, which canfbe made in small, compact sizes. readily adaptable to meet a large variety of applications, and which is thoroughly and reliably sealed against the entrance of air, gas, vapors, moisture, liquids, dust or particles of foreign matter to the switch contacts,

and which might short-circuit, corrode, film, or

insulate the contacts, or be ignited by arcing at the contacts.

Switches have heretofore been proposed which are superflcially enclosed within a rubber sheath. That type of construction is generally not satisfactory because of the diiilculty in securing a completely sealed condition and the liability of the relatively rthin sheath becoming broken or punctured and, further, because of the additional cost of the sheath. Such a switch, furthermore, retains all of the prior undesirable features of metal springs and other delicate mechanism liable to break or wear out, thus creating a high re` placement cost.

Another type of sealed switch has been designed for use in long lengths as traffic switches to lie across the path of 4moving vehicles in driveways and streets for such purposes as controlling traiilc signals, alarms, or garage doors. The design of such trafiic switches has not been adapta ble to the held of small compact hand or mechanically actuated unit switches.

An objectl ofA this invention is to provide a sealed switch of exceptionally simple, readily adaptable structure that may be produced in standardized small, compact form at low cost,

and which is eminently suitable for use in a great many places where a completely protected, relatively easily operating switch is required.

Another object is to provide a switch of this kind that maybe molded from compressible resilient insulating material, such as natural or articial rubber, intov any of a wide variety of shapes and styles lhaving predetermined operating characteristics tomeet a largerange of practical applicaftions. ,4

My switch eliminates the use of small and delicate, trouble-making parts Iand inits simplest form comprises only three parts, a hollow compressible body and a pair of contact members which are mounted within andsupported by the (C1. 20o-52)l body and movable into and out yof contact by compression and expansion of the body.r The arrangement may be such as to expose portions of the contact members to receive cur-rent conduct- 5 ing elements of an electrical circuit directly. For most purposes, however, leads may extend out from the contacts within the body for connecting the switch in an electrical circuit exterlorly of the switch body. The engagement of the leads with the contacts is such as to preclude uid leakage past the leads into the contact chamber. Thus, it is possible to produce the switch at very low cost but nevertheless of great reliability. 'Ihe manufacturing cost is so low that the switch can i5 be furnished for less than the cost of repairing more complex types of switches.

Another feature of my invention is the utillzation in the operation of 'the switch of not only the inherent resiliency of the material o! the switch body but also of the pressure of gas trapped within thebody cavity in which the contacts are located.

yAnother object is to design a switch having a resilient body completely sealing the contacts and acting, when compressed, to carry the contacts into rubbing engagement to assure a perfect electrical contact.

A further object is a weatherproof switch including a mounting peculiarly adaptable to use with a bicycle stop light and to be mounted on a rear fork member of the frame to 'be actuated by the reaction of the coaster brake arm.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which simi lar characters of referenice-y indicate similar parts throughout the several views.

Referring to the drawings:

Fig. 1 is a fragmentary view, in perspective, of the coaster brake portion. of the rear wheel of a bicycle, and the rear fork and mud guard braces, showing one ofy -my sealed switches in use as a brake-operated'signalswitch;

Fig. 2 is an enlarged end elevational view of Fig. 6 is a vertical sectional view through a mod ifled form oi the switch showing the switch body in normal or distended condition;

Fig. 7 is a vertical sectional view of the switch of Fig. 6, showing the same compressed to bring the switch contacts into engagement;

Fig. 8 is a perspective view showing the electrical contact members of the modified form of switch of Fig. 6;

Fig. 9 is a verticalsectional view through another modied form of the switch;

Fh. l is a perspective view of the contact members of the modified switch shown in Fig. 9.

Figs. 11 and 12 are vertical sectional views taken in a similar plane through a further modifled form of the switch, the switch contacts being shown in separated relation in Fig. l1 and in contacting relation in Fig. l2;

Fig. 13 is a vertical sectional view showing still another modiication of the switch, with the contacts separated: j

Fig. 14 is a vertical sectional View showing the switch of Fig. 13 compressed to bring the contacts into engagement;

Fig. 15 is a perspective view of a doorbell switch construction embodying the invention;

Fig. 16 is a vertical sectional view through the doorbell switch shown in Fig. 15;

Fig. 17 is a vertical sectional view through a modiiled form of the doorbell switch; and

Fig. 18 is a vertical sectional view through another modied form of the switch, which is of the normally closed type.

Referring to the drawings in detail, in Figs. 1 to 4, inclusive, is shown a preferred form of my switch, indicated generally by the reference numeral 2li, used as a water and dustproof stop signal light switch of a bicycle. Only fragmentary portions of the rear fork 2i and oi the rear mud guard braces 22, together with the coaster brake 23 and fragmentary portions of the spokes 24 of the bicycle are shown in Fig. l. as it. is believed that these few details will permit of full understanding of this use of the switch without more elaborate showing of the remainder of the wellknown bicycle structure. The coaster brake 23 has the usual brake arm 25, which is connected to the lower bar of the fork 2i by means of a metal strap 21 looped about the bar and detachably secured tothe arm by means of a bolt 23.

The stop light (not shown) of the bicycle may be of any preferred construction and is considered, in the present instance, as operating on a single wire hookup wherein the mud guard braces 22 are current-carrying parts of the light circuit.

The switch 20 comprises simply a small, slightly elongated hollow block body 29 `formed of a compressible resilient material enclosing a pair of contact members 30 and 3|. In the form shown, the body 23 is molded from resilient rubb'er or equivalent material of suitable resiliency, having a small, preferably central, cavity or chamber 32 which is of somewhat flattened form horizontally.

The contact members 30 and 3l may be iden-- tically formed from narrow strips of electrical conducting material, such as brass, and extend lengthwise oi' the body 23 along the top and bottom walls of the cavity 32. At their end portions the contact members are entirely embedded in the material of -the body 23 at the opposite ends of the chamber 32. The center portions of the contact members are bowed invlrdlytopreamtcontactpointsu. Therubber of the body 29, intervening between the opvposed ends of the contact strips 30 and 3i, holds the contact strips normally spaced apart.

Leading from either of the ends of the con tact strips 30 and 3i are

wires

34 and 35, re-

spectively. The ends of the wires may be secured to the strips as by soldering, and are preierably located on the opposite sides oi the contact strips from the chamber 32. An insulating l0 sheath 3l surrounds each of the

wires

34 and 35, and is preferably of a grade and type oi rubber or other material which can be vulcanized ilrmly to the body 29. The inner ends of the insulating sheaths 31 terminate a substanal distance from the chamber 32, and are thereby separated from the chamber 32 by solid portions oi the body material. Thus, even though the sheaths may accidentally be imperfectly vulcanized or even work loose, the sealed condition of the chamber 32 will remain unbroken.

In constructing the switch 2D, the body 2B may be initially molded as separate upper and lower halves A and B, with the contact strips 33 and 3i and the associated

wires

34 and 35, respectively, and their sheaths molded in place. The

halves of the body are then secured together permanently as by vulcanizing or cementing. In Figs. 3 and 4, the broken line C represents the vulcanized or cemented joint between the two halves. In the separate halves A and B, there will, of course, be shallow, matching depressions which combine to form the chamber 32 when the halves are secured together.

To close the contacts of the switch 20, the

35 upper and lower portions of the body 28 are squeezed together on an axis of compression extending through the contact points 33 until the contact points 33 interengage. In this, the portions of the body 23 which deilne the side and end Walls of the chamber 32, being of relatively reduced mass compared with the top and bottom portions of the body, will compress and dis tort more readily and thus facilitate quick contacting of the contact points. It will be ob- 4,5 served that the compact upper and lower opposed engagement faces of the body block are in more than projected co'extension with the maior or horizontal area of the chamber 32, so that when the upper and lower portions of the body are squeezed together by substantially over-al1 compressive engagement of opposed actuating members, the chamber is substantially ensmalled.

The side and end walls of the chamber 32 intersect the exure plane of the body 23 and 53 are formed concave in order to reduce distor- 50 walls to bend easily as the top and bottom por- `tions of the body come together. As shown in Fig. 3, the concavity of the side walls preferably extends laterally beyond the side edges of the contact strips 30 and 3|, thus further assuring freedom from possible interference by inward distortion of such walls. As a result of their con.- cave formation, the end Walls of the chamber 32, which extend between the anchored end portions of the contact strips 30 and 3| (Fig. 4),

tend to distort longitudinally outwardly of the body under vertical compression and thus move away from the contact points 33.

The resiliency o1' the material of the body 23 acts when the switch-closing pressure is released to return the body to the uncompressed or open switch condition. In addition, I may utilize the pressure of a compressed gas within the chamber 32 to assist in quick opening of the switch contacts upon release of the switch-closing pressure.I Any suitable gas may be utilized for this purpose but, as a matter of expediency and availability, the chamber 32 may be lled with air at ordinary atmospheric or higher pressure. As a result of the ensmallment of the chamber 32 when the switch is compressed to close the'contact points 33, not only is the material of the body compressed, but the gas within the `chamber 32 is also compressed by the closing together of the top and bottom walls of the contact chamber 32 and supplements the resiliency of the lateral walls of the cavity in urging the body block back to normal shape, and thereby the contacts back to their normal relative position. The compressed gas goes into the pockets which form at the ends and the sides of the chamber 32 by distortion of the concave end and side walls.

The arrangementA as shown in Fig. 1 is such that pressure for closing the switch is created by any application of the coaster brake 23 to stop the bicycle. For this purpose the switch is interposed between the loop of the anchoring strap 21 and the adjacent lower frame bar of the fork 2|. The strap loop snugly embraces substantially the entire engagement face of the top and also the sides ofthe body 29. Slippage of the switch body 29 from under the loop of the anchoring strap 21 is prevented by retaining beads 38 formed at the opposite ends oi' the body and spaced apart 'about' the same distance as the width of the strap.

A- saddle member 39 resting upon the fork bar provides a flat base under the switch body. The saddle member 39 may be stamped from sheet metal shaped to provide integral right angular leg flanges 40 which are cut out to form aligned downwardly opening notches 4| yfor straddling the fork bar..y The sides of thelegs 40 extend laterally beyond the side edges -of the body of the saddle and function as retaining ears .en-A gageable with the opposite edges of the anchor- `ing strap to avoid relative displacement of the saddle and strap.

When the coaster brake 23 is applied, the simultaneous downward torque exerted by the brake arm tends to rotate the latter counterclockwise so that it pulls down upon the strap 21, thus compressing the switch body 29 and rclosing the contact points 33. This completes the stop light circuit from a battery (not shown) through the wire 34, the switch 20, the wire 35, and the mud guard braces 22. An electrical connection between the wir'e 35 and the mud guard braces is perfected through an eye terminal 42 on the wire which engages the braces where the latter are secured upon the rear wheel axle.

Promptly upon release of'the coaster brake, the rebound force which has been created in the switch body 29 by its compression, returns the body to normal and thus raises the anchoring strap 21 and brake arm 25 to initial position fromv from an insulating material, assures that the switch will not short-circuit. The operation of the switch is smooth and positive. Furthermore, no special structure or reconstruction of the coaster brake is necessary to adapt the switch for operation by the coaster brake. The only change in any conventional part of the coaster brake assembly is in the arm-anchoring strap 21 which has a slightly larger loop so as to accommodate the switch.

Although the switch 20 has been described as especially adapted for use as a bicycle stop light switch, it may obviously be used for other purposes where a completely sealed switch is necessary and where base and vcompression members for operating the switch are available. It is adaptable for use in automobiles as a stoplight or starter switch, in automatic machinery where protection is necessary against oil, cutting agents, dust, and the like. Since it must withstand fairly strong pressure. sometimes of shock proportions as when the coaster brake` of the bicycle is jammed on, the switch 20 is of fairly compact and relatively stiff construction. For some uses, the switch 20 may therefore not be sufciently sensitive, that is, it may require greater than available force or pressure for operation. Because of its small, compact construction, this condition may exist even though the selected grade of rubber or other. resilient material may be as soft or flexible as practicable.

I have accordingly provided a switch 43 (Figs.

6 and 7) which is designed for more sensitive the slight downward deilection resulting from the compression.

Because of its resilient action, the switch body 29 also acts to some extent as a shock absorber for the .coaster brake.

It will be apparent that the switch 20 is permanently sealed against moisture and dirt. This,

I taken together with the fact that the body 29 of operation. The switch 43 has a hollow body 44 'provided with reasonably massive upper and lower portions joined together by comparatively much thinner and quite flexible integral vertical walls 45. The hollow interior of the body serves as a sealed contact chamber 41. The inner f aces of the'walls 45 may be concave as shown.

When pressure is applied, as for example-downwardly at the top of the body 44, on an axis of compression as indicated by the` arrow at the top of Fig. 7, the thin walls 45 will distort readily and bulge out as seen in Fig. 7 .in 4a flexure plane intersecting the axis. Thus, little, if any, compression of the more massive top and bottom portions of the switch body is required to squeeze them together.

Compression of the switch body 44, as described, brings into engagement electrical contact members 48 and 49 which are secured against the upper and lower walls, respectively, of the chamber 41. Inasmuch as the sides 45 of the switch body 44 are of such limited thickness as may preclude proper anchoring of the contact members 48 and 49 laterally beyond the chamber 41, they are provided with upwardly and inwardly directed pairs of substantially L-shaped integral anchoring flanges 59 and 5I, respectively, which are embedded in the massive portions of the switch body between the contact members and the opposite engagement faces of the body. The anchoring anges have their attached legs extending vertically and the remaining legs lying horizontally within the thrust path of the switchclosing pressure that is applied to the body 44.

lips.

form, as shown in Fig. 8, with the upper contact member 46 of concavo-convex shape. This permits the contact member 48 to make point engagement with the contact member I9, even though pressure may be applied unevenly to the switch body in closing the switch.

Electrical lead wires 62 and,63 are secured to the back faces of, respectively, the contact member lll and the contact member I9 as by means of soldering 64. The wires are encased in insulating sheaths55 vulcanized within the body. The anchored end portions of the

wires

52 and 53 are received through apertures 51 in respective ones of the anchoring flanges'50 and 5I, and are thus positively engaged and held against twisting or working loose from the contact members in the movement of the switch body incident to closing and opening of the switch.

The external shape of the switch 43,may be square, round, or any other preferred shape, and the pressure faces (the upper and lower faces as viewed in Figs. 6 and 7) are preferably flat in order to facilitate engagement of the switch body between opposed members of an operating mechanism.

For some purposes it may be desirable to have a fully sealed switch but in which direct engagement can be had with the contact members exteriorly of the switch body, and thus avoid the use of lead wires. Such a switch, identified by the numeral 60, is shown in Fig. 9, and has a compressible resilient body 6I enclosing a cavity 62 to providev a chamber for upper and lower

electrical contact members

63 and 64, respectively. The upper contact member 63 may be of concavo-convex form so as to make point contact with the lower contact member 64 when the switch is closed. Each of the contact members has a pair of substantially L-shaped anchoring flanges 65 which have their shorter legs integral with the .respective contact members and their longer legs lying in co-pianar edgewise abutting relation and provide pressure resistance reinforcements for the switch body block spaced from the upper and lower faces of the respective contact members. i

In order to permit a direct electrical connection with the contact members, the abutting long legs of the anchoring flanges 65 are exposed fiatwise to serve as friction terminals at the engagement faces of the switch body 6I. Thus, the switch is adapted to be placed directly in a holder or clip between a pair of opposed current conducting elements, such as fingers 66 in an elec.- trical circuit, without requiring connection of lead wires. This is of particular advantage in places -where replacement of the switch may have to be made with more or less frequency.

The fingers 66 of the switch holder may be in themselves resilient or may be resiliently mounted to bear yieldably but firmly against `the friction terminals of the switch 60.

In order to facilitate the insertion of the switch 60 and assure thorough electrical contact against the terminal faces thereof, the holder fingers 66 may be of slightly inwardly bowed shape and have their front ends formed as outwardly flaring The rear end portions of the fingers 66 are in the form of angular flanges which provide forwardly facing limit shoulders 66 for engagement by the opposing sides of the switch body 6I. The rearwardly projecting portions of the angular flanges are connected, as by means of anchoring rivets 66h, 'to the opposite sides of an insulating base member 66C. Terminal screws 68d are threaded into the rear anges for connecting the electrical lead wires of theV circuit to the holder.

Where the insulating member 6Ic is resilient, the entire holder may be squeezed to actuate the switch. On the other hand, the fingers 66 may be of such flexibility that they can be directly y fiexed'inwardly sufficiently to compress the switch body 6l and actuate the contacts 63 and 6l.

The contact chamber 62 has the thin side walls concave in order to reduce strain and assureoutward distortion or buckling of these walls when the switch body is compressed to close the

contacts

63 and 64. At the top and bottom of the side walls, the material of the switch body Il ,preferably extends into overlapping relation to the contact faces of the respective contact members, as indicated at 61, in order to effect a seal against leakage due to possible loosening of the body material from the outside vertical faces of 4the short legs of the anchoring flanges 65 which extend to the outside of the switch body.

Where it is desirable to have a rubbing engagement between the contacts of the switch, either the modified form of switch 1li shown in Figs. l1 and 12, or the modified switch 1l shown in Figs. 13 and 14, may be used.

The switch 10 comprises upper and lower relatively massive body portions 12"and 13, respectively, of substantially triangular shape joined together in spaced relation by relatively thin, interiorly concave integral walls 14 which seal the space between the body portions to form a chamber 15. The chamber is of flattened shape and lies at an oblique angle with relation to the upper and lower, preferably fiat, horizontal engagement faces of the switchbody. Upper and lower obliquely tilted electrical contact members 11 and 18 are supported by the body portions 12 and 13, respectively, in opposed normally spaced rela tion on the top and bottom walls of the chamber 15.` The upper contact member 11 may have a convex contact face for point engagement with the face of the lower contact member 18.

Each ofthe contact members is anchored in its respective supporting body portion by means of a pair of anchoring flanges 19 and 80 embedded therein. In each instance, the anchoring flange 19 is relatively short and extends inwardly from that portion of the edge of the associated contact member which is located nearest the adjacent engagement face of the switch body.

.The flanges are of sufficient length to extend vertically from the remote edges (considered with respect to the horizontal engagement faces) of the respective tilted contact members to points opposite the anchoring flanges 19 and have short legs 8| directed edgewise toward, but in spaced. co-planar relation to the flanges 19. Thus, the anchoring flanges are interposed between the contact members and the engagement faces of the switch body and receive equally the compression thrust to which the switch body is subjected in closing the contacts. Electric lead wires I2, encased in insulating sheaths 63 vulcanized'to the switch body, may extend through apertures Il in the anchoring flanges 80 adjacent the horizontal flange legs 8l and are soldered to the inner faces of such legs.

When the switch 10 is compressed to close the contacts, as by downward vertical pressure upon the upper face of the switch body on a central axis of compression, as indicated by the arrow at the top of Fig. 12, the side walls 14 yield by bowing outwardly until the contact member 11 engages' the inclined contact face of the member contacts and assures a positive electrical connection.

Whereas the switch is designed for a relatively small range of movement between the contact members in an angular path, the switch 1| is designed for somewhat greater, but rectilinear relative movement between the contacts. In the switch 1|-, the compressible resilient body has upper and lower relatively

massive body portions

85 and 81, respectively, provided with flat, parallel exterior engagement faces. The

portions

85 and 81 are spaced substantially apart by relatively thin, interiorly concave, integral side walls 88 sealing a contact chamber 89. At the top of the chamber 89 the upper portion 85 of the switch body supports a contact member 90 provided with a downwardly projecting boss or contact Ahea-d 9| of preferably bulbous shape. An upwardly opening socket 92 formed in a lower contact member 93 supported at the bottom of the chamber 89 is designed to receive the contact Fig. 14, the side Walls 88 become distorted and bow outwardly and the body portions k85 and 81 approach until the contact head 9| Ienters the contact socket 92. The outer transverse dimen sion of the head 9| is preferably slightly larger than the inner transverse dimension of the socket 92 so that the heady 9| will enter the socket with a frictional, rubbing action that assures thorough electrical contact between the two contact members. The Walls of the socket 92 may be formed to yield slightly when the head 9| enters it.

Connection of the switch 1 in anv electrical circuit exteriorly of the body of the vswitch may be effected through electrical leads 98 and 91 which have their ends soldered to the anchoring

flanges

94 and 95 of the respective contact members.

In Figs. and 15 is shown a modified form4 lov |00 of my switch particularly adapted for use as 'I a door bell or annunciator switch. One of the principal sources of trouble with door bell switches arises from snorting of the circuit byv entrance of moisture to the switch contacts. l 1nasmuch as the contacts in my switch are completely sealed within the Waterproof body, such trouble is avoided.

The switch |00 comprises a flat, hollow rubber l Contact The wausof the cavity at the-sides and' between the embedded end portions of the: con-'- tact members are preferably concave as in the previously described forms. Lead wires |08are secured to the opposed ends adjacent one side of the body |0|, with their rubber sheathing L09 vulcanized in the body.. The leads may extend from the switch through -a hole 0 bored through the jamb |02.

Compression against the switch -body |0| to close the contact point |01 is effected by a push button bearing against the outer face of the body |0| and held in place by a centrally perforated, laterally flanged retainer casing or housing shell ||2. The housing shell may be secured to the jamb |02 by means of washerhead screws H3. It will be clear lthat regardless of the exposure of the switch |00 to the elements, moisture cannot disrupt the electrical circuit at the switch.

In the modified form of door bell switch ||4 shown in Fig. 17, the functions are substantially like the switch |00, but the switch is made to avoid the need for a housing shell or separate push button. The switch 4 includes `a body of compressible resilient material having a cavity ||5 which houses opposed, normally spaced contact members ||1 and 8. The rear face of the switch body is fiat and is adapted to rest against a door jamb or the like (not shown). Lead wires ||9 by which the switch ||4 is connected in an electric bell or annunciator circuit extend from the contact members ||1 and ||8 out off the switch body through a recess in the rear face of the body.

' In this form, the switch body has an integral lateral flange |2| provided with holes |22 to receive the screws for securing the switch to the door jamb. In addition, the switch ||4 has molded integrally at the center of its front face, a boss |23 serving as a push button.

'Ihe door bell switch ||4 is inexpensive to make and since it is all formed in one piece, eliminates separable parts that might become lost prior to installation of the switch. Since all parts of the switch body, including the push button and the attaching flange, are formed of the same weather-resistant material, it will uniformly resist weathering and is free from the deteriorating effect of corrosion which attacks switches having exposedmetallic parts.

The switches thus far described have all been ofthe normally open style, that is, the embedded contacts are held apart by the material of the switch body in the extended or non-compressed condition of the switch, and are carried into switch closing engagement by the squeezing toward one another ofthe opposite contact carrying portions of the switch body. For some purposes it may be necessary to have al normally closed switch which may be selectively opened Aby the squeezing of the switch body. An example of such a normally closed switch, identiiied generally by the numeral |25, is shown in Fig. 18.

The switch\|25 comprises a body of resilient, compressible material and includes relatively thick head and base portions |26 and |21, respectively, which are integrally connected together by side walls |28 which hermetically seal a contact chamber |29. The inner faces of the walls |28 may be concave, as shown.

Normally closed contact members |30 and |3| are carried by the head |28 and the base |21, respectively. Each of the contact members is preferably of substantially U-shape construction, having one leg embedded in the respective sup- Dorting member parallel to the preferably hat engagement face oi such member. The web portions of the contact members extend into the chamber |29 at diametrically opposite sides, and the remaining legs |32 and |33 of the contact members extend into overlapping engagement inside of the U of the respectively opposed engagement member. The contact leg |32 may be bowed toward the contact leg |33, as indicated at |34, in order to assure thorough electrical contact therewith. Preferably, the contact legs |32 and |33 are so related that in the noncompressed condition of the switch, they bear against one another with sufcient opposing pressure to maintain e, ilrm engagement.

In the operation of the switch |25, squeezing pressure is exerted against the head and base portions |20 and |21 which carries them toward one another and causes the contact legs |32 and |33 or! the contact members to separate, thus opening the switch. At the same time the concave lateral walls |28 distort outwardly away from the` contact members.

Electrical connection of the contact members |30 and |3| is effected through the medium of electrical leads |35 and |36, respectively. The leads extend through the respective side portions of the body adjacent the webs of the contact members and through the webs and are anchored to the embedded legs of the contact members by means of solder or the like |31. The insulating sheaths |38 of the leads |are preferably molded within the material of the body.

In all forms of my switch, the contacts are completely enclosed within the dust-proof, sparkproof and fluid-proof body. The compressible, resilient material of the body may be selected for the particular qualities of resiliency and resistance to water, oil or chemicals, best adapted for the use to. which the switch is to be put. For example, an ordinary grade of natural .rubber may be suitable for uses where the switch is merely to be exposed t the weather as for example in the tail light switch 20 or the doorbell switches |00 and H4. But when the switch is to be used in places where natural rubber will not stand up because subject to oil or certain gases or strong chemical solutions as in processing tanks, appropriate types and grades of synthetic rubber may -be used. Hence, the term rubber" where used in the claims is intended to be given a generic meaning, including both natural rubber and the synthetic or so-called rubber substitutes suitable for the present purpose. In addition to the several uses Specifically illustrated or mentioned, there are of coursev many other uses rior which my switches are emisulating sheaths.

nently suitable. The switches may be formed in an innite variety of shapes to fit practically any mechanical environment and can actually be made to ilt in places where it is difficult or impossible to put ordinary switches.

Although not specifically mentioned in every instance herein, I contemplate that all of the described forms of switch or their variants may be filled with a gas (air being the form most likely used) ,under normal atmospheric or higher pressure which will be compressed when the switch is closed and thus assist in opening the switch. Each form of the switch, it will also be noted, preferably has the walls o! the contact chamber of more or \less concaveform fior the An advantage of having thecontact chambers of the switchesgas filled is that during comprespurposes described in connection with the switch" sion of the switches the pressure created by the compressing of the gas pushes the walls of the chambers laterally outwardly away from the portions of the contacts that are exposed within the chambers. This avoids any tendency of the material of the walls to bend inwardly into interferring relation with the contacts when the switch are flexed during operation of the switch.

It will be observed that in each of the forms of the switch that has lead wires extending from the contacts and out through the material oi the body, the relationship oi' the lead wires is such as to move freely with the associated parts of the switch and avoid pulling or twisting strains whichmight tend to loosen the wires or their in- 'Ihat is, the wires extend laterally of the direction of.movement of the main parts of the switch. Thus, where the movement is vertical, the wires extend from the massive portions of the switch body in horizontal directions either from the same side of the body (Figs. 4, 6, 13, 16 and 17) or from opposite sides (Figs. 11 and 18).

Instead of simple contact members of the types illustrated, over-center or eccentric mechanical contact arrangements can be secured within the sealed cavity of the switch body to provide a switch that will remain in closed condition after actuation and until reactuated to release the contact mechanism.

While the invention is susceptible of various modifications, and alternative constructions, I have shown in the drawings, and have herein described in detail certain preferred embodiments, but it is to be understood that I do not thereby intend to limit the invention to the specific forms disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the following claims.

I claim:

1. In combination in an electrical switch construction of the character described adapted for controlling a bicycle stop light circuit, a hollow body of compressible resilient material having a pair of normally spaced electrical contacts therein, a base member adapted to be mounted upon the bicycle frame and providing a broad supporting surface for said body, and a looped member engaged over said body and extending past said base member for connection to the torque arm of the bicycle coaster brake so that when the coaster brake is applied the looped member will pull against and compress the body, thus closing said contacts, the resiliency of said body being such that the body normally returns to an uncom- Pressed condition, carrying said looped member along, upon release of the pulling force from said looped member.

2. A switch construction substantially as set forth in claim 1, wherein said body carries means for engagement with said looped member to hold said body in place'.

3. A switch construction substantially as denned in claim 1, wherein the base member carries means engageable with the looped member to .hold the base member in place` with respect to the` switch body and the associated part of the bicycle frame.

4.' 'In a sealed switch unit adapted for actuation by an external movable member, a block of resilientrubber constituting a body having a cavity therein formed to provide an axis of compression extending through the cavity. and presenting exposed faces intersected by the axis for compressive engagement by the actuating member, rigid electrical contact means within the cavity adapted for relative movement into and out of contacting relation, said contact means including a sheet metal contact member having an anchoring element extending from one side thereof embedded in said body at the walls of the cavity nearest said exposed faces ot the body and extending vas a thrust resisting `reinforcement into the material of the body between the contact member and said face, whereby compression of the body. by said actuating member acting against said exposed face will also move said contact member, said anchoring element being of substantially L shape, having an apertured leg integral with the contact member and extending therefrom toward the exposed engagement face f of the body, and the other leg being directed into being anchored in electrical communication with s'aid contact member.

FRANK W, SCHWIN'N.