US3818169A

US3818169A - Push button switch

Info

Publication number: US3818169A
Application number: US00340251A
Authority: US
Inventors: W Kobernus
Original assignee: Grayhill Inc
Current assignee: Grayhill Inc
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1974-06-18
Anticipated expiration: 1991-06-18

Abstract

Simple low profile multi-contact push button switch assembly with movable contacts positioned within the push button itself. The push button slides within a tubular housing secured to a bass in which conducting pins are mounted. The push button is spring biased with respect to the base and moves to bring the contacts into engagement with the conducting pins. The movable contacts have relatively long spring arms with ends which move along ribs in the housing and into wiping engagement with fixed contacts formed by the conducting pins. One or more movable contacts can be provided with each push button, and the contacts may be of different shapes and can be interconnected to provide different switching arrangements. The conducting pins extend through the base forming terminals for connection to a circuit, and the base may be mounted directly on a printed circuit board with the terminals soldered to the conductors thereon. To facilitate the layout of the circuit on the board, the conducting pins are staggered, and the ends of the movable contacts are offset to directly engage the pins. A plurality of switches may be provided in an array for various applications, such as to provide numerical, coded keyboards.

Description

United States Patent 1191 Kobernus' 1451 June 1 1974 PUSH BUTTON SWITCH [75] Inventor: William D. Kobernus, La Grange Park, Ill.

[73] Assignee: Grayhill, Inc., La Grange, Ill. [22] Filed: Mar. 12, 1973 [2]] Appl. No.: 340,251

[52] U.S. Cl. 200/159 A, 200/16 D [5l] Int. Cl. 1101b 13/64 [58] Field of Search 200/159 A, 16 D,-16 C, '200/159 R- [56] References Cited UNITED STATES PATENTS 1,906,085 4/1933 Norviel 200/16 D 3,038,053 6/1962 Long et al 200/159 A 3,072,757 1/1963 Gluck 200/16 D 3,l42,742 7/l964 Kaleba et al 3,261,955 7/l966 Martin 3,699,292 l0/l972 Ohkita ZOO/l6 D Primary Examiner-George Harris 1 Attorney, Agent, or FirmMueller, Aichele & Ptak assembly with movable contacts positioned within the push button itself. The push button slides within a tubular housing secured to a bass in which conducting pins are mounted. The push button is spring biased with respect to the base and moves to bring the contacts into engagement with the conducting pins. The movable contacts have relatively long spring arms with ends which move along ribs in the housing and into wiping engagement with fixed contacts formed by the conducting pins. One or more movable contacts can be provided with each push button, and the contacts may be of different shapes and can be interconnected to provide different switching arrangements. The conducting pins extend through the base forming terminals for connection to a circuit, and the base may be mounted directly on a printed circuit board with the terminals soldered to the conductors thereon. To facilitate the layout of the circuit on the board, the conducting pins are staggered, and the ends of the movable contacts are offset to directly engage the pins, A plurality of switches may be provided in an array for various applications, such as to provide num'erical,'coded keyboards.

18 Claims, 13 DrawingFigures 3 38 .r'-. w '1- I 1 25a 1 I l.

r -"T 3e 5 H 118 I 5 L PUSH BUTTON SWITCH BACKGROUND OF THE INVENTION Push button switches are used in many applications, such as on control panels wherein the buttons are operated to cause various control operations. In some cases, a plurality of switches are required as to provide a numerical input. In many applications, push buttons are required on relatively small apparatus, and when a plurality of switches are required, the size of the buttons and the switches operated thereby must be small so that the size of equipment is not unduly increased thereby.

In the past it has been common practice to provide push button switches wherein'the actuator is coupled to the switch structure, but is physically separate therefrom. This results in a structure which is relatively large and is not suitable for use with miniature equipment. In many cases, it has been necessary to custom design the switch into the equipment to conserve space, thereby resulting in increased cost. Also, known switch structures are not available with the desired versatility of contact arrangements, and in arrays or modules including a plurality of switches which can be used to provide the numbers and arrangement of switches required in different applications.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved low profile push button switch structure.

A further object of the invention is to provide a push button switch wherein at least a portion of the switch contact structure is provided within the push button itself, so that relatively long spring contact arms are provided in a small overall structure.

Another object of the invention is to provide a small push button switch having a base with pins adaptable to be connected to a circuit board, with the pins forming fixed contacts which are selectively engaged by movable contacts provided within the push button actuator.

Still another object of the invention is to provide a push button switch structure having a base adapted to be mounted on a circuit board, with conducting pins therein positioned to be connected to conductors thereon, and with movable contacts extending within the push button and having resilient ends projecting therefrom for engaging the pins and providing wiping contact therewith in response to movement of the push button.

A still further object of the invention is to provide a push button switch which may have a plurality of switching contacts provided in small space, and wherein a plurality of the switches can be combined in a compact switch array.

In practicing the invention, a push button switch assembly is provided having a base which is suitable for mounting in various ways, such as on a circuit board. Conducting pins extend through the base having terminal portions for connection to conductors on a circuit board, with the pins extending above the base to form fixed switch contacts. A tubular housing is secured to the base within which a push button is moveably positioned. The push button is open on the side facing the base and has grooves therein for receiving U-shaped movable contacts. The contacts have spring arms with grooves in the housing, with a'coil spring being positioned between the base and the insert to hold the push button in the upper or unactuated position. The push button may have a cover with an edge adapted to engage a shoulder in the housing to prevent removal of the push button from the housing. By use of a transparent cover, indicia can be provided on the push button which is apparent through the cover, or indicia can be placed on or within the cover itself.

To facilitate connection of the pin terminals to conductors on a circuit board in a particular pattern, the position of the pins is staggered. The ends of the movable contacts are offset so that the contact ends correctly engage the pins. .A single contact can be provided in each push button or a plurality of contacts can be used, and the contacts can be inter-connected as desired. The ends of the contacts can be of different lengths so that connection is established with the conducting pins at different points in the movement of the push button. This permits the closing of some of the switch contacts prior to the closing of other contacts.

The base and housing are sealed together to provide an elclosure about the contacts to hold out foreign material. A single base and housing can be used for a plurality of push button switches which are provided as a module. In such case, the construction of the push buttons and the contacts can be the same as for individual switches.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the push button switch of the invention;

FIG. 2 is a side view of the push button switch;

FIG. 3 is a cross-sectional view of the switch showing the internal construction;

FIG. 4 is a bottom view of the switch showing the terminal arrangement;

FIG. 5 is a cross-sectional view of the switch along the lines 5-5 of FIG. 3;

FIG. 6 is a cross-sectional view along the lines 6-6 of FIG. 3;

FIGS. 7 and 8 are detailed views of the U-shaped movable switch contact;

FIG. 9 shows the switch with the movable switch contact in engagement with the contact pins;

FIG. 10 shows an alternate movable contact construction;

FIG. 11 illustrates a common movable contact for connecting more than two terminals;

FIG. 12 is a top view of a module including six push button switches; and

FIG. 13 shows the base of the switch module of FIG. 12.

DETAILED DESCRIPTION FIG. 1 is a top view of the switch of the invention showing the push button 10, which is of rectangular (square) configuration, within the tubular housing 12. The push button can obviously be of a different shape, such as round. FIG. 2 is a side view which in addition to showing the push button .10 and the housing 12, shows the base member 14 and the terminals 16 extending therefrom. The housing 12 has an upper reduced section 13 from which the push button ex noted that the terminals 16 are molded in the base 14,

and are the bottom ends of conducting pins which have portions 18 extending above the base forming fixed switch contacts. Terminals and fixed contacts can be provided which are of other constructions. The push button 10, is formed by a five sided cubical member 20, which has an open side facing the base 14, and a cover 22positioned about the member andhaving an outwardly extending edges 23 which holds the push button assembled to .the housing 12. The edge 23 engages internal shoudler 24, on the housing to limit the upward movement of the push button. The push button can be provided as a'single molded member with the edge 23 thereon, and can be provided by two-shot molding with a first part having indicia molded thereon, and the second molding-surounding the indicia.

One or more U-shaped spring contact members 25 are provided, with the bight thereof extending within the hollow push button 10. Ribs 21 extend inwardly from opposite walls of the member 20 providing grooves within which the arms of the spring contacts 25 are positioned, with a plurality of grooves being provided to receive a plurality of movable spring contacts. In the construction shown, up to four movable contacts can be used, but the switch can be constructed to receive a larger-or smaller number of movable contacts. An insert 28 is positioned within the member 20 in engagement with the contacts 25 at the center thereof.

This member has an 1 opening 30 for receiving coil spring 32 which holds the push button 10 in its upward position. The spring 32 can be positioned about a central projection 33 on the base 14 so that it is retained in its proper position. 1

FIGS. 5 and 6, which are cross-sectional views along the lines 5-5 and 6-6 of FIG. 3,-further illustrate the construction of the switch. FIG. 5 showsthe bottom of the insert 28, and shows the extensions 29-thereon which extends into slots 31 in the sidesof the housing 12. This guides the insert 28 as itmoves with the push button 10 in the tubular housing 12. FIG. 5 also shows the ribs 21 along the sides of the member 20 which form the grooves for receiving the contacts 25. FIGS. 5 and 6 show the use of only a single movable contact 25, but it will be apparent that three other movable contacts can also be used in the four slots provided in the construction illustrated. l

I Thehousing 12 is positioned on. the base 14 as best shown in FIGS. 3 and 6. The housing 12 has an edge 35 which fits within the upturned edge 36 of the base 14. Projections 40 extend from the housing into openings 42 in the base to key these'two parts in the proper positions. A projection 44 may beprovided adjacent the edge of the base 14, to extend into a recess 46 in one side of the housing 12, to prevent incorrect assembly of the base and the housing. The housing and base can be made of plastic material and secured together by ultrasonic welding, or other known means, to seal the enclosure about the contacts'This prevents entry of contaminants which may be present, as when the base is connected to a circuit board by machine soldering. By use of this construction the base 14 can be molded of thermosetting material and the housing 12 molded of thermoplastic material. As the base is adapted to be positioned on a-circuit board and have the terminals positioned in openings therein and soldered to conductors thereon, it will be subjected to the high temperatures used in automatic soldering, so it must be constructed to material which will withstand these temperatures. The housing can be constructed of less expensive thermoplastic material which can be'secured to the base by ultrasonic welding, and can be provided in different button 10 is pressed down, the movable'contact 25 will move downwardly, so that the curved ends 26 thereof will engage the cylindrical fixed contacts 18 formed by the contact pins, and wipe therealong, as shown in FIG.

9. As the fixed contacts 18 are cylindrical, and the ends 26 of movable contacts 25 are curved, the engagement between the fixed and movable contacts will be at a point, and the wiping action of the movable contact 25 along the fixed contact 18 would be along a line. This will act to interconnect the terminals 16 to complete a circuit therethrough, thus providing the normal switch action. If desired, the fixed contacts 18 can be positioned so .that engagement thereof by the movable spring contact results in a detent action which can be felt by the person operating the push button. When the push button 10 is released, the coil spring 32 will move the button upwardly so that the movable contact 25 moves to a position wherein the ends 26 thereof are above and out of engagement with the contacts 18. This will open the circuit through the terminals 16. Although a normally open switch contact arrangement is illustrated, a normally closed contact arrangement can' be provided.

It is apparent from FIG. 3 thatthe U-shapedmovable switch contact 25 is in contact with the member 20 and the insert 28 only at the-center thereof. This engagement'is provided by projection 48 on the member 20 and by projection 49 on the insert 28. This allows the full lengths of the arms of contact member 25 to move resiliently for good spring contact action. The contact 25 is constructed from conducting spring material, such as beryllium copper to provide effective switch action for a large number of operations. The ends curved 26 of the spring contact member 25 engage a pair of ribs 38 on the housing 12 when the button '10 is in the unactauted position. The ribs have rounded surfaces positioned to engage the contact ends 26 on opposite sides of the center part thereof which engages the contact 18. The center of the contact end which provides the switching action, therefore, does not make and break on the plastic ribs to pick up contaminants which would interfere with the switching action (FIG. 5). v

FIG. 4 is a bottom view of the base 14 showing the placement of the terminals 16. Terminals need be provided only at the positions where the contact portions will be engaged by movable contacts. It will be noted that the terminals are staggered, and this positioning is desirable when the switch is used in a circuit board. This allows freedom in the design of the conductor pattern, and facilitates connection of the terminals 16 to the conductors on the circuit board.

FIG. 7 and 8 are detail views of the switch contact 25 and illustrate that the ends 26 thereof are offset with respect to the bight or body portion of the contact so that they will engage the pin contacts 18 when posi tioned as shown in FIG. 4. FIGS. 5 and 6 also show the offset ends of the contacts. As previously stated, the ends 26 of the movable contacts as they move upward engage ribs 38 on the housing 12, with the ribs being positioned to engage the contact ends on opposite sides of the parts thereof which engage the fixed contact pins 18.

FIG. shows an unsymmetrical contact with can be used'in the switch, whereas the contact shown in FIG. 7 is symmetrical. The end 260 of the contact 25 is longer than the end 26b. This causes the end 26a to engage a contact pin 18 during movement of the push button, prior to engagement of a contact pin by the end 2612. This may be used to make a particular connection at a later point in the movement of the push button 10 than another connection is made by such movement.

FIG. 11 shows an embodiment wherein a plurality of U-shaped contacts are provided by a single conducting member 50. This member is U-shaped and can be of the shape shown in FIG. 7. The single conducting member 50 has ends 51 and 52 which connect oppositely positioned conducting pins 18, ends 53 and 54 which connect another pair of oppositely positioned pins, and ends 55 and 56 which connect a third pair of oppositely positioned pins 18. Since this is a common conducting member, all of the pins engaged by the ends of the contact 50 will be connected together. One or more of the ends can be short, as shown by end 26b in FIG. 10, if desired.

FIG. 12 is a top viewof a switch array or module which includes six push button switches of the invention. A common housing 60 is provided having six tubular recesses for receiving the six push buttons marked A, B, C, D, E and F. FIG. 13 is a view of the base member 62 for receiving the housing 60, and shows the conducting pins 18 which form the fixed contacts engaged by the movable contacts carried by the push buttons. Openings 64 are provided in the base 62 for receiving pins 65 in the housing 60 to correctly position the housing with respect to the base. The con struction of the push buttons 10, and the contacts 25 and inserts 28 therein, can be exactly the same as illustrated in FlGs. 1 to 8. The tubular portions of the housing can also have the same configuration as in the single switch housing illustrated in FIGS. 1 to 6.

The push button switch of the invention has been found to be highly satisfactory in commercial applications. The switch has a low profile, but because of the positions of the movable contacts within the push buttons, and the support thereof only at the center, the contact arms are relatively long and the curved contact ends thereof provide wiping action along a line on the cylindrical fixed contacts for highly effective switch contact action. The use of a separate housing and base facilitates the molding of the parts, and the sealing of the parts together prevents the entry of foreign material into the space about the contacts. The push buttons can be provided in two parts with a transparent cover for protecting the indicia or as a single part, which may be formed by two-shot molding. This construction facilitates the molding of the housing and the push buttons of material of various colors for the desired appearance.

The push button switch of the invention has been constructed with each side of the base having a dimension of approximately 0.68 inch, and with the overall height of the base, housing, and push button in its normal upper position being approximately 0.75 inch.

Switches can be provided individually or in arrays including a plurality of switches, thereby facilitating the use in different applications. For example, switches can be arranged to provide numerical or alphabetical coded keyboards. The switch array as illustrated in FIG. 12, which includes six switches, has been constructed with a base having a dimension of approxispring means coupled to said push button and to said base for holding said push button in a normal unoperated position, and

conducting contact means having a portion within said push button and having curved contact ends extending therefrom, said contact means being movable by said push button to a position wherein said curved ends engage said cylindrical fixed contacts.

2. A switch according to claim 1 wherein said contact means includes a U-shaped movable contact having first and second resilient arms, and wherein each of said arms has a curved end positioned for wiping engagement with one of said cylindrical fixed contacts, which wiping engagement is substantially along a line.

3. A switch according to claim 2 wherein said housing has ribs positioned to be engaged by said ends of said movable contact when said push button is in said normal unoperated position, with said ends moving into positions in engagement with said fixed contacts in response to movement of said push button.

4. A switch according to claim 2 wherein said housing has a pair of ribs positioned to engage each end of said movable contact, with said ribs engaging said end on opposite sides of the part thereof engaged by said fixed contact, and wherein said push button is operable to move said movable contact so that each of said ends slides along said ribs and then wipes along said fixed contact.

5. A switch according to claim 1 wherein said hollow push button has a plurality of grooves formed therein, and including a plurality of U-shaped contacts positioned in said grooves and movable by said push button to positions to engage said fixed contacts.

6. A switch according to claim 5 wherein at least two of said U-shaped contacts are electrically interconnected.

7. A switch according to claim 5 wherein at least one of said U-shaped contacts has an end thereof constructed to contact a fixed contact in response to movement of the push button at a point in such movement prior to the engagement of a conducting pin by another one of said contact ends.

8. A switch according to claim 1 further including an insert member within said push button in engagement with said contact, and wherein said spring means enthereof, and said housing has a shoulder engaged by said edge when said push button is in said normal unoperated position.

11. A switch according to claim 1 wherein said hollow push button includes an inner portion and a cover portion, and including a movable contact positioned in said inner portion and movable by said push button to a position in engagement with said fixed contacts.

12. A switch according to claim 11 wherein said cover portion is made of transparent material, and said inner portion includes indicia thereon which appears through said cover portion.

13. A switch according to claim 1 including a plurality of cylindrical conducting pins molded into said base and extending-therethrough, said pins having portions on one side of said base forming said fixed contacts and terminal portions on the opposite side of said base.

14. A switch according to claim 13 wherein said pins are positioned in a staggered arrangement to facilitate the connection of sadi terminal portions to conductors on a circuit board.

IS. The switch according to claim 14 wherein said contact means includes a U-shaped contact having offset ends for engaging said contact portions of said 'conducting pins.

16. A switch according to claim 13 wherein said contact means includes a U-shaped contact having first and second resilient arms andwherein each of said arms has a curved end movable by said push button into wiping engagement with said cylindrical fixed contact portion of one of said conducting pins.

17. A push button switch array including in combination:

a base having a plurality of cylindrical conducting fixed contact pins arranged in groups extending therethrough; I

a housing secured to said base having a plurality of tubular portions, each associated with one group of conducting pins;

a hollow push button slidably positoned in each of said tubular housing portions and having anopen side facing said base,

spring means coupled to each of said push buttons and said base for holding said push buttons in normal unoperated positions; and

conducting contact means positioned in each of said push buttons and having curved contact ends ex-- tending therefrom, said contact means being movable by said push button to a position wherein said a curved ends engage said cylindrical contact pins of the group associated with the tubular housing portion in which such push button is positioned.

18. A switch array according to claim 17 wherein said contact means includes a U-shaped contact having a center portion and first and second resilient arms, and wherein each of said arms has a curved end positioned for wiping engagement with one of said cylindrical contact pins to interconnect the same in response to actuation of said push button.

Claims

1. A push button switch including in combination, an insulating base having a plurality of cylindrical conducting fixed contacts extending therefrom, a tubular housing secured to said base, a hollow push button slidably positioned within said housing and having an open side facing said base, spring means coupled to said push button and to said base for holding said push button in a normal unoperated position, and conducting contact means having a portion within said push button and having curved contact ends extending therefrom, said contact means being movable by said push button to a position wherein said curved ends engage said cylindrical fixed contacts.

8. A switch according to claim 1 further including an insert member within said push button in engagement with said contact, and wherein said spring means engages said insert member for holding said push button in said unoperating position.

9. A switch according to claim 8 wherein, said contact is U-shaped and has a pair of resilient arms, said push button has a projection engaging said contact only adjacent the center thereof, and said insert has a projection engaging said contact only adjacent the center thereof, whereby said resilient arms are unrestrained by said push button.

10. A switch according to claim 1 wherein said push button has a projecting edge adjacent the open side thereof, and said housing has a shoulder engaged by said edge when said push button is in said normal unoperated position.

13. A switch according to claim 1 including a plurality of cylindrical conducting pins molded into said base and extending therethrough, said pins having portions on one side of said base forming said fixed contacts and terminal portions on the opposite side of said base.

15. The switch according to claim 14 wherein said contact means includes a U-shaped contact having offset ends for engaging said contact portions of said conducting pins.

16. A switch according to claim 13 wherein said contact means includes a U-shaped contact having first and second resilient arms and wherein each of said arms has a curved end movable by said push button into wiping engagement with said cylindrical fixed contact portion of one of said conducting pins.

17. A push button switch array including in combination: a base having a plurality of cylindrical conducting fixed contact pins arranged in groups extending therethrough; a housing secured to said base having a plurality of tubular portions, each associated with one group of conducting pins; a hollow push button slidablY positoned in each of said tubular housing portions and having an open side facing said base; spring means coupled to each of said push buttons and said base for holding said push buttons in normal unoperated positions; and conducting contact means positioned in each of said push buttons and having curved contact ends extending therefrom, said contact means being movable by said push button to a position wherein said curved ends engage said cylindrical contact pins of the group associated with the tubular housing portion in which such push button is positioned.