CA1290796C - Push-button switch - Google Patents

Abstract

ABSTRACT

A switch unit and socket member for mounting same are disclosed. The switch unit has first and second terminals disposed on its base and extending downwardly from a lower surface. Further terminals extend downwardly from the side of the base and are arranged to provide an electrical connection with the socket. Gaps are formed between these further terminals and the base in the transverse direction of the unit. The socket member has a plane portion on an upper side thereof and a number of socket holes formed in this plane portion for connecting the first and second terminals. Protrusions extend upwardly from the plane portion and are disposed at positions on the socket member corresponding to the positions of the gaps. The protrusions are insertable in respective gaps when the switch unit is mounted in the socket. Further socket holes are formed in the protrusions for insertion of the further terminals therein.

Description

This application is a division of Canaaian patent appLication No. 477,302 filed March 22, 1985.
This invention relates to a switch for various types of electronic equipment.
A switch for electronic equipment is presently known. Specifically, in an inner space between a switch cover and a switch base disposed opposite one another in the vertical direction, an upper terminal and a lower terminal are arrang~d oppGsite one another. Between the terminals is a predetermined gap. Conta~ts are secured to the opposing faces of both o~ the -terminals respectively~
A common terminal is disposed vertically on one side of the contacts. The base end of a first movable member is engaged in the lower portion of the common terminal while the free end of the first movable member is situated in the vicinity of the contacts of the above-mentioned upper and lower terminals.
A second movable member inserted between the contacts is engaged at one end thereof to the ~ree end of the first movable member. The second movable member has contacts secured at positions corresponding to the respective contacts of the upper and lower-t~rminals. Further, a spring is stretched between the outer end o~ the second movable member ~3~7~

and the common terminal, so that the contact on the second movable member is always biased to be in contact with the contact on the lower terminal.
An operation member subject to the depressing operation is supported above the free end of the second movable member. When the operation member is depressed, -the ~ree end of the second mGvable member moves downwardly to switch the contac-t of t'ne second movable member from the contact on the lower terminal to the contact on the upper terminal.
These contact structures constructea as described above have the following problems. Namely, upon switching the second movable member, the second movable member is slanted an amount corresponding to the amount of depression of the operation member resulting in a slip, due to the slanting, between the contact of the second movable member and the contact on the lower terminal in a partially contacted state.
There is a similar slippage in the contact between the contact on the upper terminal and the contact of the second movable member after the switching operation.
As a result of the slipping con~act between these contacts, the contact faces are remarkably abraded or roughened, thereby resulting in poor contact, reduction in the switch operation characteristic and, thus, reduction in the switch li~e.

379~

According to -the invention, there is provided a socket for mounting a switch unit having a switc'n base, said switch unit cornprising first and second terminals disposed on said base and extending downwardly from a lower surface of said base and further terminals disposed on said base and extending downwardly from the side of said base, said further terminals being adapted to provide an electrical connection with the socket, a gap being formed between each further terminal and said base in the transverse direction of the switch unit, said socket comprising a socket member having a plane portion on an upper side thereof, first socket holes formed in said plane portion for connecting said first and lS second terminals by insertion in said holes, protrusions extending upwardly from said plane portion and disposed at positions on said socket member corresponding to the positions of the gaps whereby said protrusions are insertable in respective gaps when said switch unit is mounted in the soc'~et, and further socket holes formed in said protrusions for insertion of said further terminals therein.

90~79~:;

downwardly extended from the side of the switch base, a gap is formed between the second terminals and the switch base opposing to each other, first socket holes are formed in the plane portion of the socket Eor connecting said first and second terminals for inserting said first terminal, protrusions are disposed at the positions corresponding to said gaps for engagement with said gaps, and second socket holes are formed in said protrusions for inserting said second terminals.
In the drawings, Figure 1 is an exploded perspective view for an illumination type push button switch;
Figure 2 is a side elevational view for the illumination type push button switch;
Figure 3 is a vertical cross-sectional view for the illumination type push button switch;
Figure ~ is a side elevational view for a portion of the switch showing the mounting state of an illumination unit to a push button unit;
Figure 5 is a side elevational view for a portion of the switch showing the mounting state of the illumination unit to the push button unit when it is reversed;
Figure 6 is a transversal cross-sectional view for a element holder portion of the illumination unit;

~9079~

Figures 7 a-~ are explanatory views showing the operation sta-te of the alternating mechanism;
Figure 8 is a vertical cross-sectional view for a socket unit portion;
Figure 9 is a partially cut-away perspective view for a socket base;
Figure lO i6 a plan view for the socket base when mounted with a lamp;
Figure ll is a plan view for the socket '~ase when mounted wi.th LED;
Figure 12 is a vertical cross-sectional view for a portion of the socket unit;
Figure 13 is a side elevational view for the socket unit;
Figure l~ is a perspective view for a switch mechanism;
Figure 15 is a perspective view for a housing mounting portion;
Figure 16 is a perspective view for a housing mounted with a resilient member;
Figure 17 is a vertical cross-sectional view for a switch socket;
Figure 1~ is a plan view for the switch socket;
Figure 19 is a perspective view for a portion of the switch socket; and Figure 20 is a vertical cross-sectional view of a conventional switch.

~9~3~9~

The drawings show an illumination type push button switch in which a push button is illuminated.
As the general contac-t structure for a push button switch, the structure shown in Figure 20 i5 known. Specifically, in an inner space between a switch cover 201 and a switch base 202, disposed opposite one another in the vertical direction, an upper terminal 203 and a lower terminal 204 are arranged opposite one another. Between the terminals is a predetermined gap. Contacts 205, 206 are secured to the opposing faces of both of the terminals 203, 204 respectively.
A common terminal 207 is disposed vertically on one side of the contacts 205, 206. The base end of a first movable member 208 is engaged in the lower portion of the common terminal 207 while the free end of the first movable member 208 is situated in the vicinity of the contacts 205, 206 of the above-mentioned upper and lower terminals 203, 204.
A second movable member 209 inserted between the contacts 205, 206 is engaged at one end thereof to the free end of the first movable member 208. The second movable member 209 has contacts 210 secured at positions corresponding to the contacts 205, 206 respectively. Further, a spring 211 is stretched between the outer end of the second movable member 209 and the common terminal 207, so that the contact '79~;

210 on the second movable member 209 is always biased to be in contact with the contact 206 on the lower terminal 204.
An operation member 212 subjec-t to the depressing operation is supported above the free end of the second movable member 209. When the operation member 212 is depressed, the free end of the second movable member 209 moves downwardly to switch the contact 210 of the second movable member 209 from the contact 206 on the lower terminal 204 to the contact 205 on the upper terminal 203.
Contact structures cons-tructed as described above have the following problems. Namely, upon switching the second movable member 209, the second movable member is slanted an amount corresponding to the amount of depression of the operation member 212 resulting in a slip, due to the slanting between the contact 210 of the second movable member 209 and the contact 206 on the lower terminal 204 in a partially contacted state. There is a similar slippage in the contact between the contact 205 on the upper terminal 203 and the contact 210 of the second movable member 209 after the switching operation.
As a result of -the slipping contact between these contacts 206, 210 and between the contacts 205, 210, the contact faces are remarkably abraded or roughened, thereby resulting in poor contact, reduction in the switch operation characteristic and, thus, reduction in the switch life.

9~

As shown in Figures 1, 2 and 3, an illumination type push button switch 20 comprises ~ push button unit 21 for switching operation, an illumination unit 22 for illuminating the illumination face, a plunger 23 for transmitting the depressing amount of the push button unit 21 downwardly, a socket unit 24 for the electrical connection of the illumination unit 22, a switch unit 25 actuated by the depression of the plunger 23, and a housing 26 for enclosing each of the elements 21 - 25.
(a) Description of the Push Button Unit The push button unit 21 is constructed as described below.
Specifically, a rectangular box-like push button 27 optionally pigmented with red, yellow, green or like other color and open at the bottom contains on the inside thereof a rectangular mark plate 28 having a mark for indicating the switching function and a rectangular diffusion plate 29 for diffusing light. A
reflection member 30 is inserted fittingly therebelow. The upper illumination face of the push button 27 is illuminated by the illumination unit (described below).
The diffusion plate 29 is recessed at the top surface thereof and the mark plate 28 fits into the recess.
The reflection memher 30 has a rectangular peripheral edge 31 forrned at the upper end thereof capable of fitting into the opening in the push button 27. A step 32 is formed on the inside of the peripheral edge 31, to which diffusion plate 29 is fitted at the lower surface thereof.

79~

Engagements 33, 33 are formed stepwise on opposite sides of t'ne outer surface of the peripheral edge 31 of the reflection member 30. Engaging protrusions 3~, 3~ are formed in the inner wall of the bottom opening of the push hu-t~on 27 and they correspond to the engagements 33, 33, so that upon fi-t-ting of the reflection member 30 to the opening, the engagements 33, 33 and the engaging protrusions 34, 34 are engaged with each other to secure together the push button 27, the mark plate 28, the diffusion plate 29 and the reflection member 30.
The circumferential surface of the reflection member 30 narrows from the upper to the lower portions as a square conical shape, in which the central portion constitutes a cylindrical portion 35, the inner peripheral surface constitutes a re1ection surface 36 slanted toward the central portion and the reflection surface 36 reflects the light rom the illumination element contained in the cylindrical portion 35 upwardly.
The cylindrical portion 35 of the re1ection member 30 is equipped with a structure for supporting the illumination unit 22 and a structure or regulating the directi.on of the illumination unit 22.
Specifically, supports 37, 37 are arranged at opposing positions on the cylindrical portion 35 of the reflection member 30 and the supports 37, 37 have elongate g~ooves 38, 38 each of a length corresponding to the depressing stroke of the push button unit 21.

The illumination unit 22 contained within the opening of the cylindrical portion 35 has pro-trusions 40 formed at the side of an element holder 39 thereof, which protrusions fi-t into the elongate grooves 38.
Further, protrusions 41, 41 acting on the supports 37, 37 are arranged at the lower outer periphery of the element holder 39.
The support 37 has a notch 4~ formed at one side edge thereof and an abutment 43 at the lower end thereof, which act as described below.
As shown in Figure 4, the notch 42 allows the protrusion 41 to be inserted the.rethrough when the protrusion 40 of the element holder 39 is fitted in the elongate groove 3~ of the support 37 in the direction of enhousing the illumination unit 22 used as the illumination type push button switch 20.
Further, as shown in Figure 5, an abutment 43 abuts against the upper surface of the protrusion 41 o~ the element holder 39 and inhibits the insertion of the protrusion 41 when the protrusion 40 of the element holder 39 is engaged in the elongate groove 38 of the support 37 in the direction of enhousing the illumination unit 22 used as a display device by rotating the illumination unit 22 by 180.

~9~7~j By the operation as described above, the direc-tion of enhousing the illumination unit 22 is regulated to a predetermined direction and, by supporting the illumination unit 22 on the supports 37, 37, assembling work for -the push button unit 21 and the illumination unit 22 is facilitated.
The cylindrical portion 35 of the reflection member 30 is equipped with a structure for connecting the plunger 23~
Specifically, engaging fingers 44, 44 are arranged at opposing positions on the cylindrical portion 35 and are displaced by 90 degrees from the positions ~f the supports 37, 37. The engaging ingers 44, 44 are formed with seizing grooves 45, 45 open at the lower ends.
The plunger 23 is in a cylindrical shape and has protrusions 46, ~6 formed on an inner wall at the upper end thereof at positions opposite to the engaging fingers 44, 44. I'he protrusions 46, 46 are engaged with and put in the seizing grooves 45, 45 in the engaging fingers 44, 44 of the reflection member when -the reflection member 30 and the plunger 23 are joined. In this manner the reflection member 30 and the plunger 23 are connected.
Furthert by the above-mentioned connection, the depressing operation of the push button unit 21 is transmitted to the plunger 23.

~;~9(J'7~

setween the cylindrical portion 35 of the reflection member 30 and the inner wall surface of the housing 26 is Eormed a seal structure.
Specifically, a step 47 is formed at the outer circumferential edge of the cylindrical portion 35 of the reflection member 30 and a step 48 formed at the upper end edge of the plunger 23 corresponds to the step 47. An annular engaging groove is formed by joining both of the steps 47, 480 A seal 49 is molded with resilient material into a circular shape surrounding the periphery and the inner end edge 50 of the seal 49 is thicker than the engaging groove formed by the steps 47, 48. When the steps 47~ 48 are joined, the inner end edge 50 is put therebetween. When the inner end edge 50 is fitted into this engaging groove, it is seized and held by the engaging groove.
The outer end edge 51 of the seal 49 fits into an annular groove 52 formed in the inner wall surface of the housing 26. An annular fixing ring 53 is fitted over the upper portion of the annular groove 52 to secure the outer end edge 51 to the annular groove 52.
The seal 49 prevents external dust or the like from entering the inside of the unit.

37~

The upper end of the housing 26 has a rectangular box-like configura-tion so tha-t the push button unit 21 constituted as described above may be fitted therein. The central portion has a cylindrical shape so that the cylindrical plunger 23 ma~ be mounted therein.
(b) Descri tion of Illumina-tion Unit P
The illumination unit 22 comprises an illumination element 54 and the element holder 39 as described above. The illumination element 5~
includes two possible types, that is, a lamp 55 and a LED 56, which are respectively fitted to the element holder 39. The type selected depends on the particular use.
Lead terminals 57, 57 of the lamp 55 are in a round bar shape and lead terminals 58, 58 of the LED
56 have a plate-like shape. The plate-like lead terminals 58, 58 are formed somewhat thinner than the round rod-like lead terminals 57, 57.
The illumination unit 22 is enclosed in and engaged to the cylindrical portion 35 at the lower end of the push button unit 21.
(c) Description of the Plunger The plunger 23 is in a cylindrical configuration and has at the upper end edge thereof a circumferential reduction step 59, which abuts against a flange 60 formed at the upper end edge of the cylindrical inner wall of the housing 26 thereby ~X~ 9~

being preven-ted ~rom slip-off when the plunger 23 i8 inser-ted from the lower end opening of the 'nousing 26.
Further, a returning spring 61 is housed in the inside of the plunger 23 and the spring 61 resiliently biases the plunger 23 upwardly by abutting at the lower end thereof against the upper surface of the socket unit.
An operation member 62 and a control mernber 63 extend from the lower peripheral edge of the plunger 23. The operation member 62 is formed as a pair, each located opposite to the switch operation portion of the switch unit 25 to perform switching operation upon depression of the plunger 23.
The control member 63 is formed with an elongate groove 64 having a length corresponding to the depressing stroke of the push button unit 21.
The elongate groove 64 is engaged with a protrusion 66 disposed on the side o:E the socket base 65 to control the depxession stroke of the plunger 23, as well as control the circumferential rota-tion of the plunger 23.
The inner circumferential wall surface at the upper end opening of the plunger 23 is provided with a control structure for limiting the direction of insertion of the illumination unit 22 to one direction.

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As shown also in Figure 6, protrusions 67, 67 protrude from the inner circumferential wall surface of the upper end opening of the plunger 23 to thereby form grooves 68 between each of the protrusions 67, 67.
The pro-trusions 67, 67 and the groove 6~ allow insertion of the protrusions 41, 41 of the illumination unit 22. When the illumination unit 22 is inserted at 180 rotation, the protrusions 67, 67 are abutted against the protrusions 41, 41 to inhibit the insertion of the illumination unit 22 therethrough.
Since the direction of inserting the illumination unit 22 is controlled to a predetermined direction by the above-mentioned regulation structure, an erroneous insertion can be prevented, for example, in a case of using the LED 56 having a polarity as the illumination element 54.
An alternating mechanism 69 is formed between the socket unit 24 of the plunger 23 and the socket base 65 of the socket unit 24.
As shown in Figures 3 and 7, the alternating mechanism 69 comprises an alternating cam 71 pivoted on the shaft 70 at the outer wall surface from the socket base 65, and a cam control portion 72 formed in the wall surface of the plunger 23 opposite to the cam 71.
The cam 71 is in a rectangular shape and has engaging grooves 73, 73 formed on two opposing shorter sides.

'7~

The cam control section 72 is defined by forming a window 74 in the wall surface of the plunger 23, in which Eour control sections 75, 76, 77, 78 are formed on the peripheral edge of the window 74.
The first control section 75 is clefined by forming an arcuate corner on one upper side of the window 74. When the cam 71 abuts against the first control section 75, the cam 71 is rotated in one direction by a predetermined angle.
The second control section 76 is definea by forming a corner at a position somewhat higher than that for the control section 75 at the other upper end of the window 74, and it controls the rotating position of the cam 71 rotated by a predetermined amount by the above-mentioned first control section 75 by engaging with the engaging groove 73 situated at the upper end of the cam 71.
The third control section 77 is defined by forming a corner on one side of the middle portion of the window 74, and it controls the position of the plunger 23 at the switch operation position by engaging the engaging groove 73 situated at the lower énd of the cam 71, the position of which is controlled by the second control section 76.
The fourth control section 78 is defined by a vertical face formed on one side of the lower portion of the window 74, and it holds the rotating state of the cam 71 which has been rotated by one-half upon successive downward movement and the subse~uent returning of the plunger 23.

7~i The alternating mechanism 69 is operated as shown in Figures a-h. Specifically, the plunger 23 is situated above and the switch is put to OFF in the state shown in Figure (a).
l~hen the plunger 23 is pushed down from this position, the first control section 75 abuts against one upper corner of the cam 71 to ro-tate the cam 71 clockwise as shown in Figure (b).
Further, when the plunger 23 is moved downwardly, the second control sec-tion 76 engages with the engaging groove 73 at the upper end of the cam 71 to stop the rotation of the cam 71 and control the position thereof as shown in Figure (c).
Then, when the plunger 23 is released, since the plunger 23 is moved upwardly by the spring 61, the third control section 77 abuts against one lower corner of the cam 71 to slightly rotate the cam 71 clockwise as shown in Figure (d).
Next, as shown in Figure (e), the third control section 77 engages the engaging groove 73 at the lower end to stop the upward movement of the plunger 23. That is, the plunger 23 is locked at that position, where the switch is operating at ON and locked at the ON state.
Then, in order to release the locked state as described above, the plunger 23 is depressed again.
Upon this depressing operation, the plunger 23 moves downwardly somewhat.
As shown in Figure (f), since the second control section 76 a~uts against one corner of the cam 71, the cam 71 is rotated clockwise to release the locked state.

~079~

As shown in Figure (g), the cam 71 is rotated substantially to a horizontal state and, upon release of the plunger 23 in this sta-te, the plunger 23 is moved upwardly by the action oE the spring 61.
In the initial stage of the upward movement, as shown in Figure (h), the third control section 77 abuts against the side portion of the cam 71 to further rotate the cam 71. When the plunger 23 moves upwaraly from this position, the side portion of the cam 71 is in sliding contact with the fourth control section 78, whereby the plunger 23 moves upwardly to the upper limit position, that is, to the position where the switch is OFF and is in the position shown by Figure (a~.
As described above, the alternating mechanism 6g can maintain the ON state of the switch by one depres~ing operation of the push button unit 21 by way of the plunger 23 and can bring the switch to the OFF state by a further single depressing operation.
In the foregoing embodiment, although the cam control portion 72 is defined by the wall surface of the plunger 23, the actuation member 62 of the plunger 23 may be made broader in the lateral direction and the cam control portion 72 may be formed to the operation member 62 as another means.
(d) Description_of the Rece~tacle Unit The socket unit 24 comprises the socket base 65 as already described and a socket cover 79 joined to the upper surface of the socket base 65.
The socket co~er 79 has an engaging structure formed at the upper surface thereof for engaging the element holder 39 for the illumination unit 22.

Specifically, engaging fingers 80, 80 e~tend upwardly from the upper surface of the socket cover 79 at a predetermined distance from each other and the engaging fingers 80, 80 respectively have seizing grooves 81, 81 each opening a-t the upper ends thereof.
Further, protrusions 82, 82 are formed on the side of the element holder 39 of the illumination unit 22 at positions opposite the engaging fingers 80, 80. The protrusions 82, 82 are engaged in and put between the seizing grooves 81, 81 of the engaging fingers 80, 80 when the lllumination unit 22 is mounted to the upper surface of the socket cover 79. In this way the illumination unit 22 is connected to the upper surface of the socket unit 24.
Further, insertion ports 83, 83 are formed in the socket cover 79 so as to penetrate the cover 79.
The insertion ports 83, 83 are formed at positions opposite to lead terminal 57 or 58 of the illumination element 54 when the illumination unit 22 is mounted to the upper surface of the socket cover 79 and allow the lead terminal 57 or 58 to pass therethrough.
Guide members 84, 84 extend upwardly from the upper surface of the socket cover 79 and they function to guide the abutment of the returning spring 61.
As shown in Figure 8 through Figure 11, soc~et holes 85, 85 are formed in the upper surface of the socket base 65 and they are formed at positions corresponding to the insertion ports 83, 83 of the socket cover 79. The socket holes 85, 85 have a ~9~796 lateral width that permits the insertion of the lead terminal 58 of the LED 56. The holes 85, 85 are formed with recesses 87, 87 at -the hole walls 86, 86 respectively, and the recesses 87, 87 are formed vertically and engaged to a portion of the circumferential surface of the round rod type lead terminals 57, 57 of the lamp 55.
Into the inside of the socket holes 85, 85 opposite to the hole walls 86, 86, are inserted the free ends of the contact member 88, 88. The contact members 88, 88 are bent at the middle portions thereof so as to provide a resiliency, and are in resilient contact with the respective lead terminals 57, 58.
The thicXness is different between the lead terminal of the lamp 55 and the lead terminals 58 of the LED 56. By fitting a portion of the lead terminal 57 of the lamp 55 to the recesses 87, 87, the protruding amount of the lead terminal 57 is substantially equal with the thickness of the lead terminal 58 of the LED 56. Thus the resiliency of the contact member 88 acts equally on both of the lead terminals 57, 58.
While the recess 87 as shown is formed in the hole wall 8~, the recess 87 may also be formed on the side of the contact member as an alternative.
As shown in Figure 12, grooves 89, 89 to be connected with the socket ho~es 85, 85 are formed in ~30~

the socket base 65 toward the outer circumference.
Engaging ports 90, 90 are formed at intermediate positions between the grooves 89, 89.
The engaging ports 90, 90 are engaged by engagements 92, 92 formed by bending -the upper ends of the connection terminals 91, 91. In this way the connection terminals 91, 91 are prevented from detachment even when t'nere is a downward pulling action acting on the connection terminals 91, 91.
To a flat por ion at the upper ends of the connection terminals 91, 91 are fixed the base ends of the con-tact members 88, 88.
Further, joining members 93, 93 are formed at positions on the peripheral edge of the socket cover 79 corresponding to the positions of the grooves 89, 89. When the joining members 93, 93 are placed in the grooves 89, 89, the upper ends of the connection terminals 91, 91 are covered to obtain satisfactory insulation for the portion of the socket holes 85, 85. At the same time, the joining position between the socket base 65 and the socket cover 79 is cont~olled by the engagemant between -the grooves 89, 89 and the joining members 93, 93.
As shown also in Figure 13, a control portion 9 Z5 is formed at the lower surface of the socket base 65, and the control portion 9~ acts on the switch unit 25 to 7~;

be described later. The specific operation will be made clear in the later explanation for the switch unit 25.
Further, connection members 95, 95 extend down from opposing positions along the circumferential edge of the socket base 65. Engaging fingers 96, 96 are formed respectively at the outer side of -the lower ends of the connectionmembers 95, 95. The engaging fingers 96, 96 are used for connecting the switch unit 25 as decribed later.
(e) Description of the Switch Unit The switch unit 25 comprises a double-throwing type switch mechanism, in which two switch mechanisms 98, 98 are constituted on a plane, and the switch mechanisms 98, 98 are actuated by the paired operation members 62, 62 o~ the plunger 23 respectively.
The switch mechanism 98 shown in Figure 14 denotes one set and the other set is constituted in a similar manner.
The one set of the switch mechanism 98 comprises a pair left and right of the first terminal 101 and second terminal 102 having secured stationary contacts 99, 100 opposed to each other one above the other. They are disposed on the switch base 97 and the respective lower ends of the terminals are extended below the switch base 97.

~ ~ ~3~

A free end of a first movable member 103 is inserted between the stationary contacts 99, 100 and the free end has a width sufficient to bridge the opposing faces of the stationary contacts 99, 99, 100, 100 situated at the left and right. Contacts 10~ are secured to the upper and lower surfaces of the broad portion for contact with each of the contacts 99, 100.
An engaging protrusion 105 is disposed at the central portion on the free end of the first movable member, and the base end of the movable member is engaged in a recess 107 formed on the lower portion of the erect member 106 located on the switch base 97.
The engaging protrusion 105 of the first movable member 103 is engaged with a hole 109 formed at one end of a second movable member 108 and the movable members 103, 108 are rotatably mounted.
The second movable member 108 has formed at one end thereof an erect member 110 formed by bending to erect a portion thereof. The erected member 110 is disposed to the switch operation portion and it is positioned to contact the lower end of the operation member 62 of the plunger 23.
One end o~ a spring 111 is connected to the erect member 110 of the second movable member 108, and the other end of the spring 111 is engaged in the recess 112 formed at the upper end of the erect member 106. The spring 111 resiliently biases the ~9~
- ~4 erect member 110 upwardly, and energizes the contact 104 of the first movable member 103 to press against -the stationary contact 104 of the terminal 102 by way of the second movable member 108.
In the state where the contact 104 is in contact with -the stationary contact 100 below, the switch function is kept at an OFF state.
When the erect member 110 is depressed by the operation member ~2 of the plunger 23 from this state, the dead point of the spring 111 is exceeded due to the downward movement of the erect member 110, whereby the second movable member 108 is reversed.
Due to the reversal, the contact 104 of the first movable member 103 moves upwardly to be in contact wtih the stationary contact 99 of the first terminal 101 above to attain the ON state of the switching function.
As described above when the contact 104 and the stationary contacts 99, 100 are in contact with or are parted from each other, there are no lateral slips between the contacts, thus preventing abrasion between them. Further, the contacts are parted from and are in contact with each other under a certain pressure of the spring 111 to attain a stable operation.
Post members 113, 113 are located at opposing positions around the peripheral edge of the upper surface of the switch base 97 and engaging holes ~9U~75~

114, 114 are formed in the inside of the base of the post members 113, 113 respectively.
The engaging holes 114, 114 are engaged with the engaging fingers 96, 96 of the connection members 95, 95 that extend down from the socket base 65 to connect them with each other.
When the socket base 65 is connected to the switch base 97 as described above, the upper surface of the switch mechanism 98 is covered by the socket ~ase 65. The covered state is particularly effective when assembling the switch. For instance, when the switch mechanism 98 is assembled and contained within the housing 26, each of the elements on the switch mechanism 98 can be prevented from contacting the opening edge of the housing 26 and disassembling.
Further, in the above-mentioned state, since the control section 94 formed to the socket base 65 is in contact with the upper surface of the spring which is left free to inhibit the swinging movement of the spring 111, each of the elements of the switch mechanism 98 can be prevented from dismantling due to the swing of the spring 111 upon assembling.
The post members 113, 113 on the switch base 97 have grooves 115, 115 formed on the outer surface thereof. The position of these grooves corr~sponds to the position of the connection terminals 91, 91 of the socket unit 24. The grooves are capable of containing the connection terminals 91, 91.

~9~7~36 In addition, gaps 116, 116 are formed between the grooves llS, 115 and the connection terminals 91, 91. The gaps 116, 116 constitute effective insula-tion w'nen the push button switch 20 is moun-tea to the switch socket as described later.
(f) Description of the Housing ~ .. .. _ ... .. . ___ ....
The housing 26 as described above, 'nas two securing means for mounting it to a mounting panel 117.
As shown in Figures 15 and 16, one of the securing means is a securing nut 118 and the other is a securing resilient member 119.
The housing 26 described above has a rectangular portion 120 formed at the upper end thereof for housing the button unit 21 described above, and a cylindrical portion 121 that is centrally located at the bottom of the rectangular portion 120.
On the inside of the cylindrical portion 121 are located the illumination unit 22, plunger 23, receptacle unit 24 and switch unit 25 described previously.
Engaging holes 122, 122 are formed at opposite sides on the lower end of the housing 26, and the engaging holes 122, 122 are engaged with engaging fingers 123, 123 formed at the side of the switch base 97. In this way the switch unit 25 is secured to the housing 26.

The lower sur~ace of the rectangular portion 120 is an engaging portion 124. Threads 125 are formed around the outer circumferential sulrface on an upper portion of the cylindrical portion 121 and are for threading engagement with the nut 118. By inser-ting the cylindrical portion 121 through the opening 126 of a mounting panel 117 and screw-coupling *he nut 118, the housing 26 can he mounted to the mounting panel 117. The mounting panel 117 is placed between the engaging portion 124 and the nut 118.
Engaging holes 127, 127 are formed on opposite sides of the threaded portion 125 of the cylindrical portion 121 and the resilient memher 119 as described abo~e is engaged to the engaging holes 127, 127.
The resilient member 119 is formed with a resilient leaf spring material and comprises a band-like portion 128 formed in an annular shape and a plurality of engaging members 129 that extend upwardly from the band-like portion 128. The band like portion 128 is split at one side so that the annular member can be extended. Lugs 130, 130 are formed at the joint in the band-like portion 128, and a lug 131 is formed on the inside at a position on the band-like portion 128 opposite to the lugs 130.

~ ~0796 The lugs 130, 131 as described above engage in the engaging holes 127, 127 of the cylindrical portion 121 respectively by extending the band-like por-tion 128.
The engaging members 129 are bent at the upper ends thereof so as to turn outwardly and the bent portion creates outward biasing force.
As described above, when the housing 26 mounted with the resilient member 119 on the cylindrical portion 121 is inserted into the opening 126 of the mounting panel 117 until the panel abuts against the engaging portion 124, the housing is secured by the engaging members 129 of the resilient member 119 that urges the opening 126 outwardly.
As described above, the mounting of the housing 26 includes two modes, that is, by means of the nut 118 and the resilient member 119, which can be used selectively.
(g) Description of the Switch Receptacle The illumination type push button switch 20 having thus been constituted is mounted to a switch soc~.et 132 to be described below.
The switch socket 132 has a cylindrical shape, in which socket holes 133 are formed at positions on the upper plane corresponding to the first and second terminals 101, 102 of the switch unit 25. Contact 79~i rnembers 134 are contained in the socket holes 133 with the contac-t members 13~ being electrically connected respectively with the terminals 101, 102.
Further, protrusions 135, 135 are provided on the switch receptacle 132 at positions corresponding to the connection terminals 91, 91 of the socket unit 24. The protrusions 135, 135 are inserted in the grooves 115, 115 ~ormed in the post members 113, 113 of the switch base 97 and inserted in the gaps 116, 116 between the grooves 115, 115 and the connection terminals 91, 91.
Then, socket holes 136, 136 are formed on the outer side of the protrusions 135, 135 and contact members 137, 137 are contained within the socket holes 136, 136. The contact members 137, 137 are electrically connected with the connection terminals 91, 91.
In the switch socket 132 thus constructed, the creeping distance between the connection terminals 91, 91 and other terminals 101, 102 is increased to improve the insulation per~ormance. Accordingly, the protrusions 135, 135 are inserted between the connection terminals 91, 91 and other terminals 101, 102, when the illumination type push button switch 20 is mounted.

In the illumination type push button switch 20 and the switch socket 132 described above, improvements have been obtained in switch operation characteristics, workability in the assernbling of each of the elements and, the insulation performance.
However, this invention is no way limited only to the structure of the described preferred embodiment but it may be made with modifications based on the spirit of this invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A socket for mounting a switch unit having a switch base, said switch unit comprising first and second terminals disposed on said base and extending downwardly from a lower surface of said base and further terminals disposed on said base and extending downwardly from the side of said base, said further terminals being adapted to provide an electrical connection with the socket, a gap being formed between each further terminal and said base in the transverse direction or the switch unit, said socket comprising a socket member having a plane portion on an upper side thereof, first socket holes formed in said plane portion for connecting said first and second terminals by insertion in said holes, protrusions extending upwardly from said plane portion and disposed at positions on said socket member corresponding to the positions of the gaps whereby said protrusions are insertable in respective gaps when said switch unit is mounted in the socket, and further socket holes formed in said protrusions for insertion of said further terminals therein.

2. A socket according to claim 1 wherein electrical contact members are arranged in said first socket holes for electrically connecting said first and second terminals.

3. A socket according to claim 2 including additional electrical contact members contained in said further socket holes and adapted for electrical connection with said further terminals.

4. A socket according to claim 1, 2 or 3 wherein said protrusions are arranged on said socket member so as to be between the first and second terminals and respective further terminals when said switch unit is mounted in said socket.