US3708635A

US3708635A - Multiple switch assembly with improved reciprocating leaf spring contact cam actuator

Info

Publication number: US3708635A
Authority: US
Inventors: C Cosley; W Streuer
Original assignee: Oak Electro Netics Corp
Current assignee: Oak Electro Netics Corp
Priority date: 1971-06-17
Filing date: 1971-06-17
Publication date: 1973-01-02
Anticipated expiration: 1990-01-02
Also published as: GB1391348A; DE2228987A1; JPS542170U; FR2142061A1; IT965815B; FR2142061B1

Abstract

A pushbutton switch of the type in which a moving plunger is effective to open and close terminal contact springs. The terminal contact springs within the switch housing are biased in such a way that when in the closed position, the contacts are firmly held together preventing momentary separation. The switches may be mounted in a group by spring clips or the like, either integral with a mounting plate or as a separate part used therewith.

Description

[111 3,708,635 [4 1 Jan. 2, 1973 United States Patent. [191 Cosley et a].

[54] MULTIILE SWITCH ASSEMBLY WITH .200/ l 6 RX 200/5 EA .200/5 EA 2,870,273 1/1959 Merchant....................... 2,748,205 5/1956 Forstrom.............. IMPROVED RECIPROCATING LEAF 2,773,139 12/1956 Forstrom et SPRING CONTACT CAM ACTUATOR [75] Inventors: Colman Cosley, Streamwood; Wll- Primary Examiner-j-R-scott v helm A. Strcuer, Mount Prospect, Markey et both of III. [5

] ABSTRACT A pushbutton switch of the type in which a moving Corp., Crystal Assignee: Oak Electro/Netics Lake, lll. plunger is effective to open and close terminal contact Flledl J 1971 springs. The terminal contact springs within the switch housing are biased in such a way that when in the [21] Appl' 154,031 closed position, the contacts are firmly held together preventing momentary separation. The switches may be mounted in a group by spring clips or the like,

- either integral with a mounting plate or as a separate part used therewith.

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References Cited UNITED STATES PATENTS 17 Claims, 14 Drawing Figures 3,218,238 Bauer et al........................200/5 R X Il hal W r [\1 4.

MULTIPLE SWITCH ASSEMBLY WITH IMPROVED RECIPROCATING LEAF SPRING CONTACT CAM ACTUATOR SUMMARY OF THE INVENTION The present invention relates to an improved pushbutton switch and particularly to a construction of the type described which prevents momentary separation of the contacts when in the closed position.

Another purpose is a simply constructed reliably operable pushbutton switch of the type described.

Another purpose is a pushbutton switch which holds circuit board from pressure applied to the switch.

Other purposes will appear in the ensuing specification, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated diagrammatically in the following drawings wherein: I

FIG. 1 is an exploded perspective illustrating a switch of the type described,

FIG. 2 is a side view of one of the housing halves used in the switch construction of FIG. 1,

FIG. 3 is a side view, similar to FIG. 2, but illustrating the contacts and plunger positioned within the housing half,

FIG. 4 is a section along plane 44 of FIG. 2,

FIG. 5 is a section along plane 5-5 of FIG. 2,

FIG. 6 is a section along plane 6-6 of FIG. 2,

FIG. 7 is a section along plane -77 of FIG. 2,

F IG. 8 is a top plan view of a switch mounting arrangement showing a pair of switches positioned therein,

FIG. 9 is a sideview .of the switch mounting arrangemm of FIG. 8,

FIG. 10 is a section along plane l0 10 ofFIG. 9,

FIG. 11 is a partial top plan view of a modified form of switch mounting arrangement,

FIG. 12 is a partial side view of a switch in the mounting arrangement of FIG. 1 1,

FIG. 13 is a partial end view of the mounting arrangement of FIGS. 1 l and -I2, and

FIG. 14 is a section along plane l4-l4 of FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 a pair of housing halves or elements are indicated at 10 and 12. Preferably the housing elements are symmetrical and formed of a suitable plastic material which permits them to be ultrasonically welded together after assembly of the contacts and plunger described hereinafter. The housing elements 10 and 12 are hollow for positioning of the switch contacts andthe plunger as described. Only one of the housing elements will be described as they are symmetrical.

An opening 14 surrounded by a flange 16 may be positioned at the top of each of the housing elements to receive a plunger indicated generally at 18. 'The plunger 18 may have a bottom stem portion 20 surrounded by a coil spring 22 which maintains the plunger in the upward position of FIG. 3. The coil spring may be seated in a depression 24, illustrated in FIG. 1, which is circular in configuration. Beneath the depression 24 is an opening 26 which receives the stem 20 when the plunger is depressed. A passage 28 connects the opening 26 and the depression 24. The plunger 18 may have an exterior portion 30 which in conventional use will have a knob, button or key attached thereto. A pair of cams 32 extend outwardly from the sides of an enlarged portion 34 of the plunger, with the cams being used to open and close the switch contacts within the housing.

A pair of terminal contact springs are indicated at 36 and 38. Each of the contact springs 36 and 38 may have terminal portions 40 and 42 which extend outwardly throughthe bottom of the housing, for example for use in connection with a printed circuit board. Adjacent the top of terminal contact spring 36 are a pair of laterally extending wings 44 which are adapted to be positioned against an interior portion of the housing as described hereinafter. Contact 38 has a bead 46 adjacent its upper end, which bead will be contacted by cam 32 when the plunger is moved into the housing. Contact 38 also has a ridge 48 which is positioned to be placed in contact with terminal contact spring 36 when the plunger is moved into'the housing. The terminal contact springs 36 and 38 are normally open contacts which are closed by depressing plunger 18.

A projection 50 is positioned on one side of each of the housing elements and there is a symmetrical generally identically positioned projection 52 on the other side of each of the housing elements. Adjacent the bottom of each housing element are-a plurality of grooves indicated at 54, 56, 58 and 60. Terminal contact springs 36 and 38 are positioned within grooves 54 and 56. Tabs or the like 62 are formed in those portions of the terminal contact springs 36 and 38 positioned within grooves 54 and 56 and there are mating portions in the grooves 54 and 56to receive the tabs 62 to thus firmly position the terminal contact springs within the grooves and to prevent any relative movement between these members and the housing. It is important to note that both grooves 54 and 56 slant inwardly toward the center of the housing or-toward the plunger. When terminal contact springs 36 and 38 are positioned within the housing, the slant of the grooves 54 and 56 is effective to direct the terminal contact springs toward the plunger. Terminal contact spring 36, however, has its laterally extending wings 44 positioned against the projections 50 and thus is under tension or is flexed when positioned within the housing. Note FIG. 3. Terminal contact spring 36 is flexed outwardly toward the outside wall of the housing. Groove 54, in combination with the projection 50, places terminal contact'spring 36 under tension and in effect biases the terminal contact spring firmly against the projections 50. As terminal contact springs 36 and 38 are normally open, terminal contact spring 38 is free within the housing.

When the plunger 18 is depressed, cam 32 will strike bead 46 and move terminal contact spring 38 outwardly against terminal contact spring 36. As the cam moves further into the housing, terminal contact spring 36 will be moved away from projection 50, and will be flexed even further in an outward direction. Thus, cam 32 holds terminal contact spring 38 against terminal contact spring 36 and the flexure of terminal contact spring 36 holds it firmly in contact with terminal contact spring 38. Vibration or shock will not cause a momentary separation of the contacts. Both terminal contact springs are flexed away from their normal direction and are thus held firmly in contact with each other.

A second pair of terminal contact springs is indicated at 64 and 66 and function as normally closed contacts. Each have terminal portions 68 which extend outwardly from the bottom of the housing again for attachment to a printed circuit board. Terminal contact springs 64 and 66 are positioned within grooves 58 and 60 which again direct the springs, in their free state, toward the center of the switch housing, or toward the plunger. Terminal contact spring 64 has a pair of laterally spaced and upwardly-directed wings 70 which will be in contact with projections 52, as illustrated in FIG. 3. Terminal contact spring 66 has a bead 72 and a ridge 74 which is normally closed against a ridge 76 on terminalcontact spring 64 when the contacts are in the closed position. Again, there are tabs or the like 78 formed adjacent the bottom of the terminal contact springs which mate with portions of the grooves 58 and 60 to firmly and properly position the terminal contact springs within the housing. Both terminal contact springs 64 and 66 will be flexed outward as they are positioned against the outside surfaces of projections 52.

In operation, when the plunger 18 is in the up position of FIG. 3, terminal contact springs 64 and 66 are closed. The outward flexure away from the natural inward direction holds terminal contact spring 64 into contact with terminal contact spring 66 and thus holds the contacts together, preventing any bounce or momentary separation of the terminal contact springs from vibration or shock. When plunger 18 moves into the housing, cam 32 will strike bead 72 and move terminal contact spring 66 away from terminal contact spring 64', thus opening the connection between the two terminal contactsprings.

Although the switch structure has been shown and described ashaving one pair of normally open contacts and a second pair of normally closed contacts, it should be obvious that the switch may include all normally open contacts or all normally closed contacts. Also there may be only one pair of contacts with a particular switch rather than two pairs.

In FIGS. 8 and 9, a generally U-shaped trough is indicated at 80 and includes a bottom 82 and side walls 84 and 86. There are a series of locations for receiving the switch housing described above. Each such location may include openings 88 for receiving the terminals of the switches and inwardly-directed projections 90, two from each of the sides 86 and 84. As illustrated in FIG. 8, each of the switches 92 will fit between the projections 90 preventing side movement in the trough 80. Between each pair of projections 90 is a spring clip 94 which may be integral with the sides 84 and 86 and an inwardly-directed portion 96 at its lower edge. The inwardly-directed portion 96 prevents upward removal of the switches 92 from the U-shaped trough 80. There is a recess 98 extending peripherally about the switch 92 when it is assembled. The inwardly-directed ends 96 of the spring clips 94 will fit into the recesses 98 and thus hold the switches 92 firmly in position in the U- shaped trough 80. Note particularly FIG. 10 which illustrates the details of the manner in which the switches are held in position.

FIGS. 11-14 show a second form of switch mounting arrangement. A plate 100 is spaced from the upper surface of a printed circuit board indicated at 102. The plate 100 may have a plurality of openings 104 for receiving switches of the type described. Cooperating with each opening 104 is a pair of spring clips 106. The upper end of each of the spring clips 106 has tabs or the like 108 and 1 10 which extend over the top of the plate 100. The bottom of each of the spring clips 106 has fingers 112 ,which extend into openings or the like 114 near the bottom of the switch elements 10 and 12. Thus, the spring clips are firmly anchored to each switch and the top of the spring clips are attached to the plate 100. There is a space between the bottom of each of the switches and the printed circuit board 102. It has been found in previous switch assembly arrangements that if someone accidentally applies pressure to the top of the switch that the switch can be pushed down and cause damage to the printed circuit board. By having a space between the bottom of the switch and the top of the printed circuit board, and by having the switches firmly anchored to the plate 100, there is no likelihood of any damage to the printed circuit board by pressure applied to the top of the switch.

In assembly, each of the spring clips are first attached to the switches. Thespring clips are'made of a light gauge sheet metal and are flexible or resilient, so that when the switches with the spring clips attached thereto are pushed down into the openings 104, the spring clips will be forced inwardly by the sides of the openings until such time as they may snap outwardly when the upper edge 116 has passed the bottom of the plate 100. The tabs 108 and 110 will then firmly hold the switches in position relative to plate 100.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that there maybe many modifications, substitutions and alterations thereto.

we claim:

1. A switch including a housing, a plunger reciprocally movable within said housing, at least two leaf spring contacts within said housing and having portions thereof extending outside of said housing for connection into an electrical circuit, said plunger having portions positioned to engage at least one of said leaf spring contacts, said leaf spring contacts being movable by said plunger between an open position in which there is no contact between said, leaf spring contacts, and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions for placing said leaf spring contacts under tension including an opening for each leaf spring contact, with a portion thereof passing through the opening and with said opening being directed toward said plunger, at least one of said leaf spring contacts being urged against one of the cooperating portions of the housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact.

2. The structure of claim 1 further characterized in that said cooperating portions of the housing include a projection extending generally toward the central portion of the housing.

3. The structure of claim 1 further characterized in that said contacts are normally in an open position, movement of the plunger within the housing moving said contacts toward a closed position in which said one contact is moved away from said cooperating portion of the housing.

4. The structure of claim 1 further characterized in that said contacts are normally closed.

5. The structure of claim 1 further characterized in that said housing is hollow and is formed of two generally symmetrical parts.

6. The structure of claim 1 further characterized in that there are four leaf spring contacts positioned within said housing, with all of said leaf spring contacts being directed toward the plunger.

7. The structure of claim 6 further characterized by and including at least two projections extending outwardly into the interior of said housing, there being a pair of leaf spring contacts associated with each projection.

8. The structure of claim 7 further characterized in that less than all of said leaf spring contacts are urged into contact with said inwardly-directed projections.

9. The structure of claim 1 further characterized in that said one leaf spring contact includes a pair of outwardly-extending wings in contact with said housing cooperating portion.

10. The structure of claim 1 further characterized in that said one leaf spring contact is directed toward said plunger in its free state, but is flexed away from said plunger by said cooperating portion.

11. A switch including a housing, a plunger reciprocally movable within said housing, at least two leaf spring contacts within said housing and having portions thereof extending outside of said housing for connection into an electrical circuit, said plunger having portions positioned to engage at least one of said leaf spring contacts, said leaf spring contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts, and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions for placing said leaf spring contacts under tension including a pair of oppositely-disposed projections, each extending generally toward the interior of the housing, at least one of said leaf spring contacts being urged against one of .said oppositely-disposed projections, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact.

12. In a switching arrangement, a plurality of switch assemblies, each including a housing, a plunger reciprocal within said housing, each switch assembly between said leaf spring contacts, said housing having cooperating portions thereof placing said leaf spring contacts under tension, with at least one of said leaf spring contacts being urged against one of said cooperating portions of said housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact,

a mounting plate having a plurality of openings, one for each switch assembly, spring clips associated with each opening for positioning a switch assembly therein, portions of said spring clips overlying said plate, and portions of said spring clips being in operable engagement with each switch assembly.

13. The structure of claim 12 further characterized in that there are a pair of spring clips for each opening, with each of said clips having fingers in operable engagement with a portion of the switch assembly.

14. The structure of claim 12 further characterized in that each of said switch assemblies have openings in the exterior thereof to receive said fingers.

15. In a switching arrangement, a plurality of switch assemblies, each including a housing, a plunger reciprocal within said housing, each switch assembly including at least two leaf spring contacts having portions thereof extending outside of said housing for connection into an electrical circuit, said contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions thereof placing said leaf spring contacts under tension, with at least one of said leaf spring contacts being -urged against one of said cooperating portions of said housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact,

a generally U-shaped mounting plate for said switch assemblies, means defining a position for each switch assembly, and spring clips integral with the generally U-shaped mounting plate and positioned for operable engagement with each switch assembly. Y

16. The structure of claim 15 further characterized by and including a plurality of projections inwardly directed and positioned for holding each switch assembly, said projections being integral with the U- shaped mounting means.

17. The structure of claim 16 further characterized in that said spring clips are positioned generally between said inwardly-directed projections.

Claims

1. A switch including a housing, a plunger reciprocally movable within said housing, at least two leaf spring contacts within said housing and having portions thereof extending outside of said housing for connection into an electrical circuit, said plunger having portions positioned to engage at least one of said leaf spring contacts, said leaf spring contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts, and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions for placing said leaf spring contacts under tension including an opening for each leaf spring contact, with a portion thereof passing through the opening and with said opening being directed toward said plunger, at least one of said leaf spring contacts being urged against one of the cooperating portions of the housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact.

11. A switch including a housing, a plunger reciprocally movable within said housing, at least two leaf spring contacts within said housing and having portions thereof extending outside of said housing for connection into an electrical circuit, said plunger having portions positioned to engage at least one of said leaf spring contacts, said leaf spring contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts, and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions for placing said leaf spring contacts under tension including a pair of oppositely-disposed projections, each extending generally toward the interior of the housing, at least one of said leaf spring contacts being urged against one of said oppositely-disposed projections, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact.

12. In a switching arrangement, a plurality of switch assemblies, each including a housing, a plunger reciprocal within said housing, each switch assembly including at least two leaf spring contacts having portions thereof extending outside of said housing for connection into an electrical circuit, said contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions thereof placing said leaf spring contacts under tension, with at least one of said leaf spring contacts being urged against one of said cooperating portions of said housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact, a mounting plate having a plurality of openings, one for each switch assembly, spring clips associated with each opening for positioning a switch assembly therein, portions of said spring clips overlying said plate, and portions of said spring clips being in operable engagement with each switch assembly.

15. In a switching arrangement, a plurality of switch assemblies, each including a housing, a plunger reciprocal within said housing, each switch assembly including at least two leaf spring contacts having portions thereof extending outside of said housing for connection into an electrical circuit, said contacts being movable by said plunger between an open position in which there is no contact between said leaf spring contacts and a closed position in which there is contact between said leaf spring contacts, said housing having cooperating portions thereof placing said leaf spring contacts under tension, with at least one of said leaf spring contacts being urged against one of said cooperating portions of said housing, inward movement of said plunger moving the other leaf spring contact away from the plunger increasing the tension of said other leaf spring contact, a generally U-shaped mounting plate for said switch assemblies, means defining a position for each switch assembly, and spring clips integral with the generally U-shaped mounting plate and positioned for operable engagement with each switch assembly.

16. The structure of claim 15 further characterized by and including a plurality of projections inwardly directed and positioned for holding each switch assembly, said projections being integral with the U-shaped mounting means.