US3719788A

US3719788A - Switch having ganged contacts mounted on opposite sides of circuit board

Info

Publication number: US3719788A
Application number: US00112583A
Authority: US
Inventors: K Holland; A Sprando
Original assignee: Tektronix Inc
Current assignee: Tektronix Inc
Priority date: 1971-02-04
Filing date: 1971-02-04
Publication date: 1973-03-06
Anticipated expiration: 1990-03-06
Also published as: JPS5533133B2; JPS534229B1; JPS5253280A; FR2124457B1; DE2205114C3; GB1361541A; NL159224B; DE2205114A1; NL7201282A; FR2124457A1; CA943172A; DE2205114B2

Abstract

A switch apparatus is described including a pair of movable contacts separately mounted on opposite sides of an etched circuit board and ganged together by a loose coupling including a coupling member extending through a hole in such circuit board. Fixed contacts are provided as conductive strips on both sides of the circuit board and the movable contacts are moved in and out of engagement with such fixed contacts by a rotary cam actuator mounted on such circuit board. In one embodiment, a cam follower surface is provided on one of a pair of insulator members joining the movable contacts to mounting springs, while in another embodiment the cam follower surface is provided on one end on the coupling member and such coupling member extends through a hole in the support portion of one of the movable contacts, while its other end engages the support portion of the other movable contact. The movable contacts may be short circuiting contacts each including a pair of spaced leg portions through which current flows in opposite directions to produce opposing fields which reduce the contact inductance.

Description

United States Patent [191 Holland et a1. A

[54] SWITCH HAVING GANGED CONTACTS MOUNTED ON OPPOSITE SIDES OF CIRCUIT BOARD [75] Inventors: Kenneth Holland; Anthony E. Sprando, both of Portland, Oreg.

[73] Assignee: Tektronix, Inc., Beaverton, Oreg. [22] Filed: Feb, 4, 1971 211' Appl. No.: 112,583

[52] u.s. Cl. ..200/1s3 LB, 200/6 BB, 200/166 J [51] Int. Cl. ..H0lh 3/42, I-IOlh 19/62 [58] Field of Search ..200/l66 PC, 153 LB, 166 J, 200/6 BB, 1 TK, 37 A, 30 AA [56] References Cited UNITED STATES PATENTS 2,033,005 3/1936 Pinkus ..200/30 AA 2,873,324 2/1959 3,499,128 3/1970 3,562,464 2/1971 3,193,651 7/1965 3,256,401 6/1966 Dawson ..200/l66 .1 X FOREIGN PATENTS OR APPLICATIONS 929,312 5/1955 Germany ..200/153 LB 1,531,565

5/1968 France ..200/153 LB [451 March 6, 1973 Primary Examiner-Herman J. l-Iohauser Assistant Examiner--Robert A. Vanderhye v Attorney-Buckhorn, Blore, Klarquist and Sparkman [5 7] ABSTRACT A switch apparatus is described including a pair of movable contacts separately mounted on opposite sides of an etched circuit board and ganged together by a loose coupling including a coupling member ex- 7 tending through a hole in such circuit board. Fixed contacts are provided as conductive strips on both sides of the circuit board and the movable contacts are moved in and out of engagement with such fixed contacts by a rotary cam actuator mounted on such circuit board. In one embodiment, acam follower surface is provided on one of a pair of insulator members joining the movable contacts to mounting springs, while in another embodiment the cam follower surface is provided on one end on the coupling member and such coupling member extends through a hole in the support portion of one of the movable contacts, while its other end engages the support portion of the other movable contact. The movable contacts may be short circuiting contacts each including a pair of spaced leg portions through which current flows in opposite directions to produce opposing fields which reduce the contact inductance.

17 Claims, 4 Drawing Figures PATENTEDHAR 61975 LLAND SPRANDO INVENTORS.

KENNETH C. HO ANTHONY E.

FIG. 4

BUCKHORN, BLORE, KLARQUIST 8. SPARKMAN ATTORNEYS SWITCII HAVING GANGED CONTACTS MOUNTED ON OPPOSITE SIDES OF CIRCUIT I BOARD BACKGROUND OF THE INVENTION The subject matter of the present invention relates surface provided on the coupling member or on an ingenerally to electrical switch apparatus, and in particular, to switch apparatus including a pair of ganged movable contacts mounted on the opposite sides of an insulator plate, such as an etched circuit board, having fixed contacts provided thereon,--such as conductive strips coated on the circuit board. The movable contacts are ganged together by a loose coupling including a movable coupling member extending through a hole in such circuit board. Rotary cam actuating means mounted onone side of the circuit board may be employed to move the movable contacts by engagement with a cam follower surface provided either on an insulator member joining the movable contact to a mounting spring or on one end of the coupling member. As a including a coupling member extending through a hole result of the gauging operation of the coupling member, cam actuation of onemovable contact toward the circuit board causes the other movable contact to be moved away from the circuit board. In one embodiment, the movable contact is joined through an insulator member to a mounting spring to insulate such contact which lowers the stray capacitance of such movahis contact.

Previously, in French Pat. No. 1,531,565, it has been proposed to provide a cam actuated switch in which two movable contacts are provided on opposite sides of a printed circuit board by forming such contacts integral with a common spring support member fixedly attached at one end to the circuit board and extending through a hole in such circuit board. As a result of not separately mounting-the pair of movable contacts on two different mounting springs and ganging them together with a loose coupling in the manner of the present invention, it would be much more difficult to manufacture the prior art switch. Also, this has the disadvantage that the two movable contacts must always be electrically connected together and can not be insulated from each other. The inductance and the stray capacitance of the contacts is much greater than that of the present invention so that such prior switch apparatus is not capable of as good a high frequency response. In addition, the switch apparatus of the present invention has low contact resistance and low open switch capacitance. As compared to previous switch apparatus having cam actuated contacts mounted on one side of the circuit board, the present invention is more compact and requires less operating force, while at the same time, having a long useful lifetime and a relatively inexpensive construction.

It is therefore one object of the present invention to provide an improved switch apparatus of compact and inexpensive construction having low inductance and capacitance so that it is capable of high frequency response.

Another object is to provide such a switch apparatus in which the movable contacts are separately mounted by different mounting springson opposite sides of a circuit board and are ganged together for simultaneous movement of both of such contacts by means of a common actuator.

sulator member joined to one movable contact.

An additional object of the present invention is to provide such a switch apparatus in which the movable contacts are ganged together by a loose coupling means in the circuit board which enables relative movement between the movable contacts.

Still another object of the invention is to provide such a switch apparatus in which the movable contacts are insulated from their mounting springs by insulator members to provide the movable contact with a low stray capacitance and a low inductance.

A still further object of the present invention is to provide such a switch apparatus in which each movable contact acts as a short-circuiting switch between two fixed contacts and is provided with two spaced leg portions through which current flows in opposite directions to produce opposing fields which reduce the contact inductance. I

Other objects and advantages of the present invention will be apparent from the following detailed description of certain preferred embodiments thereof and from the attached drawings of which:

FIG. 1' is a perspective plan view of one embodiment of the switch apparatus of the present invention with parts broken away for purposes of clarity;

FIG. 2 is an enlarged sectional view taken along the line 2-2 of FIG. 1. I

FIG. 3 is a sectional view of a portion of another embodiment of the switch apparatus of the present invention employing a different type of cam follower and coupling means;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIGS. 1 and 2, one embodiment of the switch apparatus of the present invention includes a pair of

movable switch contacts

10 and 12 joined through

insulator members

14 and 16 to one end of leaf

spring mounting members

18 and 20. The movable contacts are separately mounted on opposite sides of an etched circuit board 22 by attaching the other ends of mounting

springs

18 and 20 to the circuit board with a common rivet eyelet24 extending through an aperture in such circuit board. The

movable contacts

10 and 12 are ganged together by a coupling member 26 of insulating material extending through an opening 28 in the circuit board and loosely coupling the two

insulator members

14 and 16. Thus, downward movement of insulator 14, to move contact 10 toward the circuit board, is transmitted through coupling member 26 to insulator 16 which moves contact 12 away from such circuit board. In the embodiment shown, one end of the coupling member 26 is attached to the insulator 16,

such as by molding these members out of an integral piece of plastic material. The other end of the coupling member is free to engage and disengage the other'insulator 14 to enable relative movement between the contacts l and 12 as shown in FIG. 2. A spacer portion 29 projects from insulator 16 into contact with the circuit board 22 in the closed position of movable contact 12 to set the proper amount of bending of such contact.

As shown in FIG. 1, each of the movable contacts and 12 is provided with a pair of

leg portions

30 and 32 which are spaced apart and extend substantially parallel from their free ends to their other ends joined in common to the

insulator

14 or 16. The

leg portions

30 and 32 have bifurcated contacts at their free ends for engagement with two

fixed contacts

34 and 36, respectively, provided as spaced metal strips coated on both sides of the circuit board 22. Thus, the

movable contacts

10 and 12 each short circuit the two

fixed contacts

34 and 36 when such movable contacts engage such fixed contacts. Current flows in opposite directions through the

leg portions

30 and 32 of the movable contact and produce opposing magnetic fields which tend to cancel and, therefore, reduce the contact inductance. As shown in FIG. 2, the two pairs of

fixed contacts

34 and 36 on opposite sides of the circuit board are displaced with the upper pair being positioned to the left of the lower pair to reduce the capacitance between such pairs of contacts.

The

movable contacts

10 and 12 are insulated from their mounting springs 18 and which lowers the stray capacitance between such movable contacts and the environment as well as reducing the inductance of such contacts. In addition, the open circuit capacitance between the movable contacts and the fixed contacts is also reduced because it is formed by two capacitances connected in series. The result is a switch apparatus which is capable of an extremely high frequency response, for example, up to 5 gigahertz. This enables the switch to be employed to connect two 50 ohm characteristic impedance strip line type transmission lines together which may be formed by conductive strips on opposite sides of the circuit board 22. In addition, the switch apparatus can also be used as a low impedance or high impedance attenuator switch with equally good results because it has a low stray capacitance providing a high impedance in parallel with the attenuator elements.

A common actuating means, such as a rotary cam drum 38, is employed to actuate the switch apparatus of FIGS. 1 and 2 by engagement with a cam follower projection 40 on the insulator member 14. The cam drum 38 is of a suitable plastic material and has cam projections 42 molded into its outer surface. Such cam drum is rotated by a control shaft 44 connected at one end to the cam drum and at its other end to a knob 46. The control shaft 44 and the cam drum 38 are mounted on the circuit board 22 by a suitable mounting means 48 atthe opposite ends of such drum to provide unitary switch apparatus. The mounting means 48 may be similar to that shown in co-pending U. S. application, Ser. No. 765,597, filed Oct. 7, 1968, by Vollum et al., now U.S. Pat. No. 3,562,464. Alternatively, it is also possible to operate the cam follower 40 with a sliding cam actuating means of the type shown in the abovementioned patent. Of course, other actuating means can be employed including those of the electromechanical type such as a solenoid, with the plunger of the solenoid moving one of the

insulator members

14 and 16 when the coil of such solenoid is energized.

Another embodiment of the present invention is shown in the FIGS. 3 and 4 which is similar to that previously described except that it employs a different coupling member 50 and different

movable contacts

52 and 54 which are formed integral with their mounting springs out of a single piece of metal. As shown in FIG. 3, the coupling member 50 is provided with a cam follower surface on an enlarged head portion 56 of conical configuration at one end of such coupling member by molding it out of a suitable plastic material. The coupling member extends through a hole in the mounting spring portion of the upper movable contact 52 and on through the opening 28 in the circuit board 22 so that its other end engages the lower movable contact 54 at its mounting spring portion. Rotation of the cam drum 38 brings a cam projection 42 into engagement with the cam follower surface 56 and causes the coupling member 50 to move downward. The coupling member 50 then closes movable contact 52 after opening movable contact 54.

The

movable contacts

52 and 54 each have spaced parallel leg portions 30' and 32' which are similar to those of FIG. 1, but are not bifurcated. These leg portions 30 and 32' engage fixed

contacts

34 and 36 provided as metal strips coated on the surface of the circuit board 22. These metal strips may be provided with gold plating in the contact areas since such strips are usually made of copper, in order to improve their electrical characteristics. It should also be noted that while the

movable contacts

52 and 54, and their spring mounting portions are electrically connected together and not insulated from each other like the embodiment of FIG. 1, the two movable contacts may be insulated from each other by fastening the leaf springs with separate solder connections rather than the common rivet 24 of FIG. 1. Thus, while the movable contacts are shown as shorting switches for interconnecting the two fixed

contacts

34 and 36 as shown in FIG. 4, they may also be used to electrically connect a single fixed contact to a terminal strip connect to,the fixed end of the leaf spring. Again, it should be noted that another common actuator, such as a sliding cam actuator mechanism, can be employed rather than the rotary cam drum 38.

It will be obvious to those having ordinary skill in the art that many changes may be made in the details of the above-described preferred embodiments of the present invention without departing from the spirit of the invention. Therefore, the scope of the present invention should only be determined by the following claims.

We claim:

1. Switch apparatus comprising:

a support plate of insulating material;

a pairof fixed switch contacts attached to the opposite sides of said support plate;

a pair of movable switch contacts mounted by two separate resilient mounting means on said opposite sides of said support plate for movement between a closed position engaging said fixed contacts and an open position spaced from said fixed contacts, said movable contacts being each attached to said resilient mounting means through an insulator member, and;

common actuator means for moving both of said movable contacts toward and away from said support plate between said open and closed positions,

including a movable coupling member extending through an opening in said support plate to couple said movable contacts together and operate them as ganged contacts.

2 Switch apparatus in accordance with claim 1 in which the coupling member loosely couples the movable contacts for movement together while enabling relative movement between said movable contacts.

3. Switch apparatus in accordance with claim 1 in which the support plate is a circuit board with the fixed contacts being metal layers on said circuit board and the actuator means is a cam actuator means.

4. Switch apparatus in accordance with claim 3 in which .the cam actuator means includes a rotary cam member. mounted on the circuit board and the two mounting means are spring members attached to opposite sides of the circuit board.

5. Switch apparatus in accordance with claim 4 in which the cam actuator means includes a cam follower of plastic insulating material which moves at least one of the movable contacts between said open and closed positions when said cam follower is engaged by said cam member.

6. Switch apparatus in accordance with claim 5 in which the cam follower is provided as a cam engaging portion on one of a pair of insulator members connecting each of said movable contacts to one end of a leaf spring mounting member having its other end attached to the circuit board.

7. Switch apparatus in accordance with claim 6 in which the other insulator member is provided with a spacer portion projecting toward the circuit board which engages the circuit board in the closed position of the movable contact connected to said other insulator member to set the amount of bending of such movable contact in said closed position.

8. Switch apparatus comprising:

a support plate of insulating material;

a pair of fixed switch contacts attached to the opposite sides of said support plate;

a pair of movable switch contacts mounted by two separate mounting means on said opposite sides of a said support plate for movement between a closed position engaging said fixed contacts and an open position spaced from said fixed contacts;

common actuator means including a movable cam member for moving both of said movable contacts toward andaway from said support plate between said open and closed positions;

said actuator means also including a movable coupling member with a cam follower portion engagedby said cam member extending through an opening in said support plate to couple said movable contacts together and operate them as ganged contacts.

9. Switch apparatus in'accordance with claim 8 in which the coupling member loosely couples the movable contacts for; movement together while enabling relative movement between said movable contacts.

10. Switch apparatus in accordance with claim 8 in which the support plate is a circuit board with the fixed contacts being metal layers on said circuit board and the actuator means is a cam actuator means.

11. Switch apparatus in accordance with claim 10 in which the cam actuator means includes a rotary cam member mounted on the circuit board and the two mounting means are resilient members attached to opposite sides of the circuit board.

12. Switch apparatus in accordance with claim 11 in which the cam actuator means includes a cam follower of plastic insulating material which moves at least one of the movable contacts between said open and closed positions when said cam follower is engaged by said cam member.

13. Switch apparatus in accordance with claim 12 in which the movable contacts have spring mounting portions attached to said circuit board, and the cam follower is provided as a cam engaging portion of one end of said coupling member, said coupling member extending through a hole in one of said spring portions and engaging the other of said spring portions with its larged head portion having the cam follower portion thereon.

15. Switch apparatus comprising:

a support plate of insulating material;

a plurality of spaced fixed switch contact means on said support plate;

a plurality of movable switch contact means mounted by resilient mounting means on said support plate for movement between a closed position engaging said fixed switch contact means and an open position spaced from said fixed switch contact means, said movable switch contact means being connected to said resilient mounting means through insulation means and said insulation means including means to couple said movable switch contact means together; and

common actuator means for moving said plurality of movable switch contact means toward and away from said support plate between said open and closed positions including actuator-engaging means provided by said insulation means for engagement by said common actuator means to operate said plurality of movable switch contact means as ganged switch contact means.

16. Switch apparatus comprising! a support plate of insulating material;

a plurality of spaced fixed switch contact means on said support plate; v

a plurality of movable switch means including resilient mounting means mounting said movable switch means on said support plate and movable switch contact means for movement between a closed position engaging said fixed switch contact means and an open position spaced from said fixed switch contact means;

insulation means extending between said plurality of movable switch means for coupling (connecting) said movable switch means together; and

common actuator means for moving said plurality of movable switch means toward and away from said support plate between said open and closed positions including actuator-engaging means provided by said insulation means for engagement by said common actuator means to operate said plurality V nected to said insulation means and another end defining contact-engaging means for engagement with said fixed switch contact means, said insulation means insulating said resilient mounting means from said contact element means; and

actuator means for moving said movable switch contact means toward and away from said support plate between open and closed contact positions including actuator-engaging means provided by said insulation means for engagement by said actuator means to operate said movable switch contact means between said open and closed positions.

Claims

1. Switch apparatus comprising: a support plate of insulating material; a pair of fixed switch contacts attached to the opposite sides of said support plate; a pair of movable switch contacts mounted by two separate resilient mounting means on said opposite sides of said support plate for movement between a closed position engaging said fixed contacts and an open position spaced from said fixed contacts, said movable contacts being each attached to said resilient mounting means through an insulator member, and; common actuator means for moving both of said movable contacts toward and away from said support plate between said open and closed positions, including a movable coupling member extending through an opening in said support plate to couple said movable contacts together and operate them as ganged contacts.

2. Switch apparatus in accordance with claim 1 in which the coupling member loosely couples the movable contacts for movement together while enabling relative movement between said movable contacts.

4. Switch apparatus in accordance with claim 3 in which the cam actuator means includes a rotary cam member mounted on the circuit board and the two mounting means are spring members attached to opposite sides of the circuit board.

8. Switch apparatus comprising: a support plate of insulating material; a pair of fixed switch contacts attached to the opposite sides of said support plate; a pair of movable switch contacts mounted by two separate mounting means on said opposite sides of said support plate for movement between a closed position engaging said fixed contacts and an open position spaced from said fixed contacts; common actuator means including a movable cam member for moving both of said movable contacts toward and away from said support plate between said open and closed positions; said actuator means also including a movable coupling member with a cam follower portion engaged by said cam member extending through an opening in said support plate to couple said movable contacts together and operate them as ganged contacts.

9. Switch apparatus in accordance with claim 8 in which the coupling member loosely couples the movable contacts for movement together while enabling relative movement between said movable contacts.

13. Switch apparatus in accordance with claim 12 in which the movable contacts have spring mounting portions attached to said circuit board, and the cam follower is provided as a cam engaging portion of one end of said coupling member, said coupling member extending through a hole in one of said spring portions and engaging the other of said spring portions with its other end.

14. Switch apparatus in accordance with claim 8 in which the coupling member is of insulating material and extends through a hole in a support portion of one of the movable contacts so that an enlarged head portion at one end of said coupling member engages said one movable contact and the other end of said coupling member engages the other movable contact, said enlarged head portion having the cam follower portion thereon.

15. Switch apparatus comprising: a support plate of insulating material; a plurality of spaced fixed switch contact means on said support plate; a plurality of movable switch contact means mounted by resilient mounting means on said support plate for movement between a closed position engaging said fixed switch contact means and an open position spaced from said fixed switch contact means, said movable switch contact means being connected to said resilient mounting means through insulation means and said insulation means including means to couple said movable switch contact means together; and common actuator means for moving said plurality of movable switch contact means toward and away from said sUpport plate between said open and closed positions including actuator-engaging means provided by said insulation means for engagement by said common actuator means to operate said plurality of movable switch contact means as ganged switch contact means.

16. Switch apparatus comprising: a support plate of insulating material; a plurality of spaced fixed switch contact means on said support plate; a plurality of movable switch means including resilient mounting means mounting said movable switch means on said support plate and movable switch contact means for movement between a closed position engaging said fixed switch contact means and an open position spaced from said fixed switch contact means; insulation means extending between said plurality of movable switch means for coupling (connecting) said movable switch means together; and common actuator means for moving said plurality of movable switch means toward and away from said support plate between said open and closed positions including actuator-engaging means provided by said insulation means for engagement by said common actuator means to operate said plurality of movable switch means as ganged switch contact means.