GB2160364A

GB2160364A - Electric switching device

Info

Publication number: GB2160364A
Application number: GB08519081A
Authority: GB
Inventors: Kozo Maenishi; Masaaki Adachi; Yoshihide Bando; Muneo Nakata; Yasuhiro Kubota
Original assignee: Omron Tateisi Electronics Co
Current assignee: Omron Corp
Priority date: 1981-01-30
Filing date: 1985-07-29
Publication date: 1985-12-18
Also published as: GB8519082D0; FR2499309B1; GB2160363B; GB2160365B; GB2094554B; GB2094554A; DE3203005C2; GB2160365A; GB8519080D0; FR2499309A1; GB8519081D0; DE3203005A1; GB2160363A; DE3249831C2; GB2160364B

Abstract

An electrical contact switching device for switching high frequency signals comprises a housing 1 and three conductors extending through a wall of the housing 1 and providing internal contact members 15a, 16a, 17a disposed in alignment with each other and external contact members 15a, 16a, 17a. One internal contact member 16a constitutes a common contact member disposed between the other two internal contact members 15a, 17a. First and second movable contact blades 21,22 are disposed on opposite sides of the aligned contact members. The first blade 21 connects the common contact member 16a and contact member 15a, and the second blade 22 connects the common contact member 16a and contact member 17a, the blades being movable in substantially opposite directions to make and break the internal electrical connections. A conductive surface within the housing is contactable by each of the contact blades when not making an internal electrical connection between two of the internal contact members, the conductive surface being electrically connected to second external connecting means 12, 13 provided on the housing. <IMAGE>

Description

1

SPECIFICATION

Electric contact switching device.

This invention relates to an electric contact switching device comprising a contact switching mechanism and a housing member supporting the electric switching mechanism, and more particularly to an improved switching device capable of switching high-frequency signals.

Generally, a conventional electric contact switching device designed for switching low-frequency signals cannot be used as a high-frequency signal switching device because a desired isolation in transmission lines cannot be performed, unnecessary radiation occurs within the device, and its gain is extremely attenuated. A high-frequency contact switching device is well known which includes a metal shielding housing for enclosing a switching mechanism and is constructed in a coaxial configuration. Such a conventional high-frequency contact switching device, however, hasthe disadvantage that the metal housing must be made oflan expensive material with a carefullytooled machine.

Itis,therefore, a primaryobjectof this invention to provide an electric contact switching devicewhich is easyto asembleata lowcostand capableof performing an improved switching operation notonly with respectto lowfrequency signals butalsowith respectto high-frequency signals.

It is afurtherobject of this inventionto provide an electric contact switching devicewhich can provide a good isolation high-frequency signals.

Itis another object of this inventionto provide an electric contact switching devicewhich includes a contact switching nnechanism forconnection to an inner conductor of an external coaxial cable and a molded base member carrying an electrically conductive memberfor connection to an outer conductor of the cable. According to this invention, there is provided an electric contact switching device cornprising:

a member for housing the switch; three conductors extending through a wall of the housing each providing an internal contact member 110 forthe switch and disposed in alignmentwith each other, and an external contact memberfor making first external connections to the device, one internal contact member constituting a common contact member disposed between the othertwo internal 115 contact members, first and second movable contact blades within the housing member and disposed on opposite sides of the said aligned contact members, the first blade serving to make an internal electrical connection between a first pair of contacts comprising 120 the common contact member and one of the othertwo internal contact members, and the second blade serving to make internal electrical connection between a second pair of contacts comprising the central contact member and the other of the two contact members, the blades being movable in substantially opposite directions to break the internal electrical connection made by one blade and one pair of internal contact members and then make an internal electrical connection by the other blade between the other pair GB 2 160 364 A 1 of contact members; the blades being subsequently movable in the reverse direction to breakthe then existing internal electrical connection and remake the f irst-mentioned internal electrical connection; a conductive surface within the housing which is contactable byeach of thecontact bladeswhen not making an internal electrical connection between two of the internal contact members, the conductive surface being electrically connected to second external connecting means provided on the housing.

Other objects and numerous advantages of the electric contact switching device according to this invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective disassembled view of an electric contact switching device as a preferred embodiment of this invention; Figure 2 is a top plan assembled sectional view showing the switching device of Figure -i; Figure 3 is a fragmentary sectional detailed view for illustrating an electrically conductive member disposed on a base member of the switching device of Figure2; Figure 4 is a side sectional view of the device of Figure-2; Figure 5A is a side assembled sectional view of an electrical contact switching device as a modification of the embodiment of Figure 1; Figure 513 is a sectional view illustrating an external terminal which is employed in the device of Figure 5A; Figure 5C is a sectional view illustrating a modified external terminal which is emloyed in the device of Figure5A; Figure 6A is aside assembled sectional vi-W of an electrical contact switching device as anot!.-r modification of the device of Figure 1; Figures 613 and 6C show modified external terminals which maybe employed in the device of Figure 6A; Figure 7 is a perspective disassembled view of an electric contact switching device as another embodiment of this invention; Figure 8 is a top plan assembled view showing the device of Figure 7; and Figure 9 is a side assembled sectional view of the device of Fig u re 7.

Referring, now, to Figures 1, 2 and 4there is shown an electric contact switching device as a preferred embodiment of this invention. The electric contact switching device includes a base member 40, a contact switching mechanism 50 housed within and supported by the base member 40, and a cover member 23 mounted on the base member40.

The base member 40 includes a base 1 and external terminals 12 and 13 secured thereto. The base 1 is a molded plastice, and may be made of a non-crystailine thermoplastic resin such as polysullphone, a thermosetting resin such as polyethersu [phone, orABS resin.

As illustrated in Figure 3, the base 1 is covered with an electrically conductive layer 11 by plating, electroplat;ng, vacuum vapor deposition, coating with an appropriate paint orthe like. The layer 11 is electrically connected to terminals 12 and 13. The base 1 includes holes 2,3 and 4 which extend vertically there-through, 2 GB 2 160 364 A 2 and at a side medial portion thereof a recessed portion 1 a. A resetting spring 5 is inserted into the portion 1 a. The base 1 further includes grooves 8 and 9 in which are slidably inserted cards orslidable members 6 and 7. Thus, the holes 2,3 and 4 and the grooves 8 and 9 provide a recessed portion 10 for housing the switching mechanism 50. Innerconductors 15,16 and 17 are supported by di-electric blocks 18,19 and 20, and inserted intothe holes 2,3 and 4, respectively. The inner conductors 15,16 and 17 serve at the bottom portions thereof as external terminals, and at the upper portions thereof as stationary contacts 15a, 16a and 17a, respectively. Thus, the inner conductors 15, 16 and 17 and the conductive layer 11 are insulated from each otherthrough blocks 18,19 and 20 in view of d.c., and compose a predetermined circuit impedance ordistributed constant.

The cards 6 and 7, respectively, carry movable contact blades 21 and 22, and are atthe ends thereof biased byspring 5 as illustrated in Figure 2. Then,the blade 21 contacts an innerwall of the base 1 covered with conductive layer 11 (see Figure 3), butthe blade 22 short-circuits the stationary contacts 16a and 17a. As illustrated in Figure 4, the cover member 23 of electrically conductive material is fixedly mounted on an uppersurface of base 1 by a clip orthe like, and electrically connected to the layer 11.

If the cards 6 and 7 are pushed againstthe spring 5 by an actuator (notshown) which is manually, mechanically or electromagnetically operated,the blade 21 short-circuits the contacts 15a and 16a and the blade 22 contactsthe conductive layer 11 disposed on an innerwall of the base I.Thus, inner conductors 15,16 and 17, respectively, serve as normally-open, common and normal ly-closed term ina Is of this electri100 cally contact switching device.

Though the base 1 of insulating material has on its surface a conductive layer, a high frequency current can concentratedly flow th rough the layer 11 accord- ing to its skin effect, wherby isolation asto highfrequency signals can be performed. Though the base 1 is made of insulating resin in this embodiment, it mayalernatively be a ceramic orconductive resin member. When the base 1 is made of a conductive resin, such as a polyester or polytetrafluoroethylene containing carbon or iron dust, a silicone rubber containing silver, aluminium or copper dust, orthe like, the conductive layer 11 is intimately connected to the base 1 th roug h the conductive dust contained therin, particularlywhen the layer 11 is formed by electroplating. Such conductive base (1) improves the conductivity of the external terminals 12 and 13 with layer 11. As compared with the metal housing body employed in the conventional device,the base 1 made of the a bove-mentio ned material is easy to be fabricated at a reduced cost and can provide a switching device of reduced weight.

The layer 11 is disposed on the innerwall surface of the base 1 so asto contactwith movable contact blade 21 or22 in a contact-break position, wherebyany high-frequency short circuit cannot be produced by electrostatic coupling among stationary contacts 16a and 15a (17a) and conductive layer 11 through movable blade21 (22). In otherwords, excellent isolation from high-frequency signals can be obtained 130 without increasing the stroke of the blades 21 and 22, and the switching device in this embodiment can be miniaturized.

According to this embodiment, there is provided an electric contact switching device including first external connecting members (15,16 and 17), first conductor members (1 5a, 16a, 17a, 21 and 22), housing members (1 and 23), second external connecting member (11) and second conductor member (11). The first external connecting members (1 5to 17) are designed to be connected to a signal line of a low-frequency coaxial cable, or an inner conductor of a high-frequency coaxial cable, and the second external connecting member (11) is designed to be connected to aground line of the low-frequency cable oran outer conductor of the coaxial cable.

Though the conductive layer 11 in this embudiment is disposed on all of the surfaces of the base 1, it may be locally disposed as long as itsatisfies circuit design requirements, such as circuit impedance, voltage standing wave ratio, distributed constant, shielding and so forth. For instance, the conductive layer 11 may be disposed only on the surfaces of inner walls of the base 1, in which external terminals 12 and 13 desirably extend through base 1 (as illustrated byterminals 147 in Figure 9) for connection with the layer 11. For switching high-frequency signals, e.g., 1 giga hertz, the layer 11 may be limitedly disposed on one wall of base 1 in parallel with the blades 21 and 22, in which layer 11 is connected with terminals 12 and 13 through a certain connection lead. The layer 11 is effective for shielding the switching mechanism 50 from external noise, but the minimum portion of the base 1 which should be covered with the layer 11 depends on the frequency of signals applied to this switching device. The cover member 23 is made of a conductive metal material but it may be of an insulating plastic.

If desired, the member 23 may be omitted. If the recessed portion 10 is fairly deep and surrounded with conductive layer 11, whether the member 23 is conductive or not does not affect the high-frequency characteristic of this device.

Returning to figure 5Athere is shown an electric contact switching device as a modification of the embodiment of Figure 1. In Figure 5A the external terminals 12 and 13 embedded into the base 1 as shown in Figure 4 are represented by projections 12a and 13a which are molded with base 1 as a single unit and plated with conductive layer 11 as illustrated in detail in Figure 5B. The layer 11 not only provides conductively in the terminals 12a and 13a, but also reinforces the same. Since the parts of the terminals 12a and 13a are simultaneously formed with the base land not required to be assembled with the same, the assembling work is simplified and a good conductivity between terminals 12a (1 3a) and conductive layer 11 is ensured.

In Figure 5C, there is shown an improved external terminal 12b (13b) which is a modification of the terminal 12a (13a). When the switching device of Figure 5A is mounted on a printed circuit board and theterminals 12a and 13a are soldered, a high temperature is applied to theterminais 12a and 13a. If the terminals 12a and 13a are made of synthetic resin such as ABS resin and are heated, the resin becomes 3 GB 2 160 364 A 3 soft and produces gasseswithin the conductive layer 11 coating theterminals 12a and 13a so asto explode theterminals 12a and 13a. Theterminal 12b (13b) of Figure 5C has a recessed bottom end and is covered with an electroless plating layer 1 la and an electro- 70 plating layer 11 b. The electroless plating layer 11 a is a nickel or copper plating layer 0.2 to 0.5 microns thick, and uniformly formed on all of the surfaces of the base 1 including the recessed portion of terminal 12b(13b).

Then, the electroplated layer 11 b of nickel or the like 75 which is easyto be soldered with solder is formed on the layer 11 a except the recessed portion of the terminal 12b (1 3b) is becomes soft on heating and produce gasses therewithin, the recessed portion only is easy to be broken so as to exhaust the pressured 80 gasses, and the terminal 12b (1 3b) is not destroyed by the heat of soldering. Forthis purpose, the bottom portion of the terminal 12a (1 3a) shown in Figure 513 maybe cutoff afterforming the layer 11, or left unplated.

If the electric contact switching device in the foregoing discription is used in such a mannerthatthe external terminals (12,13) as outer conductor termin als or ground terminals are not needed because of the peripheral condition of circuits or parts connected 90 with this device, the external terminals (12,13) maybe omitted. For instance, a socket for receiving the switching device is designed to contact a flat plated external surface portion of the base 1 for connection with the plated layer 11, the projecting terminals (12, 13) maybe omitted. Particularly, unless the device is used for switching high-frequency signals, such projecting ground terminals (12,13) are not neces sary.

Figure 6A illustrates an electric contact switching 100 device as another modification of the embodiment of Figu re 4. The device of Figure 6A is designed for connection with coaxial cables, and includes outer connecting terminals 41,42 and 43 which are molded with the base 1 as a single unit and plated with a 105 conducting layer (not shown). The respective termin als 41,42 and 43 can be directly connected with connectors of coaxial cables. Figures 613 and 6C illustrate modified external terminals for connection with connectors of external coaxial cables. In Figu re 110 6B the molded base 1 includes a cylindrical projection on which a threaded metal sleeve 60 istightly mounted. The sleeve 60 may be mounted on the projection 70 which is plated with a conductive layer (not shown). Alternatively, the conductive layer may be plated after mounting the sleeve 60 on the projection 70. In Figure 6C a sleeve 61 is inserted and secured into a recessed portion 71 of base 1 which is formed in a hole 3a for supporting a dielectric block 19 carrying an inner conductor 16. A conductive layer (not shown) may be disposed on the base 1 before or after insertion by sleeve 61 to the base 1.

Returning to figures 7 to 9 there is illustrated an electric contact switching device, viz., an electro magnetic relay, as another embodiment of this invention. A base or housing 110 is a box-shaped molded plastic, and all of the surfacethereof are plated with a conductive material (notshown). The conductive plating layer covering the base 110 rein forcesthe base 110. The base 110 includes a separat- ing wall 111 to thereby provided a pair of compartements 112 and 113. An electromagnet 114 is disposed within the compartment 112 of base 110, which includes on iron core 115, a spool 116, a coil 117, and an L-shaped yoke secured to the core 115. A pair of leads 119 and 120 are embedded in the spool 116, and are piercing through a bottom wall portion 121 of base 110. An L-shaped movable lever 122 is pivotally supported bya hinge spring 123with respectto an edge portion 118a of theyoke 118.The spring 123 at its base end 123a is mounted on a pair of (upper and lower) recesssed portions 11 8b of theyoke 118. An L-shaped fixing member 124 is engaged with the yoke 118 and inserted into a vertically grooved portion 125 formed in the base 110 so asto fixthe yoke 118tothe bottom wall portion 121.

A resetting leaf spring 126 is inserted within the compartment 112 so asto be engaged with a pairof projections 131 a and 131 b and be biased bythe lever 122 at its end portion 122c. A pair of cards 127 and 128 at their engaging portions 127a and 128a are engaged with a pair of actuating portions 129 and 130 of the leaf spring 126.

The cards 127 and 128 are slidably guided bya pair of grooves 134and 135formed inthe compartment 113 of the base 110. The card 127 carries a movable contact blade 139forswitching circuitacross stationary contact members 136 and 137.The card 128 carries a movablecontact blade 140forswitching a circuit across stationary contact members 137 and 138. Dielectric blocks 141,142 and 143 supporting contact members 136,137 and 138 are inserted into holes 144, 145 and 146formed in the bottom wall portion 121 of base 110 as illustrated in Figure 9. Outer conductor lead terminals 147 are inserted into holes 150 extending through the bottom portion 121 of base 110 so as to block any high frequency currentflow between terminal portions 136a and 137a of member 136 and 137 and between terminal portions 137a and 138a of members 137 and 138. The holes 150 on the inner surfaces are coated with a conductive layer-forming material not shown extending over all of the surfaces of the base 11 Ofor electrical connection with terminals 147. A metal plate 160 is mounted overthe compartment 113 as a shielding member, and an uppercover 152 is mounted on the base 110 as illustrated in Figure 9. The cover 152 is a molded plastic haiving a sepa rating wall 154 confronting the wal 1111 of the base 110. The cover 152 further has projections 155 and 156 for ensuring the sliding movement of the cards 127 and 128. Though the cover 152 is not covered with a conductive layer, it may be metalplated as a shielding member. The plate 160 may be omitted, if desired.

In the above-mentioned construction, ifthe coil 117 is energized, the lever 122 is attracted bythe core 115. Then, the end portion 122c of the attracted lever 122 pushes the spring 126 in the direction of the solid arrow-markshown in Figure 8, and the cards 127 and 128 areforwardly moved bythe spring 126 through its portions 129 and 130. Accordingly, the blade 139 leaves from the contact members 136 and 137 and the blade 140 contacts the contact members 137 and 138. That is, the connection with the common contact 137 is switched from the break contact 136 to the make 4 GB 2 160 364 A 4 contact 138. If the coil 117 is disenergized,the blades 139 and 140 return totheiroriginal positions illustrated in Figure 8.

Normally,the blade 140 contacts projections 149a and 149bformed in the base 110. When the coil 117 is energized, the blade 139 contacts projections 148a and 148b. The projections 148a, 148b, 148c, 149b and 149c have conductive layers extending to the terminals 147. Therefore, the blades 139 and 140 are prevented from making any unnecessary high-frequency short circuit among contact members 136,137 and 138.

Alternatively, the blades 139 and 140 may be assembled in such a mannerthat normallythe blade 139 contactsthe projections 149c and 149a and the blade 140 contacts the members 137 and 138, while when the coil 117 is energized,the blade 139 contacts the members 136 and 137 and the blade 140 contacts the projections 148b and 148c. Thus, bychanging the inserting position forthe blades 139 and 140, the switching mode of this relay can be reversed.

Though the switching device in this embodiment is designed fora highfrequency switch of giga hertz order, it may be used as d.c. or lowfrequency switch.

The switching device in this embodiment may be modified so thatthe respective cards 127 and 128 carry a plurality of blades so as to provide a switching device which switches a plurality of circuits.

Thus, according to this invention there is provided an electric contact switching device including a switching mechanism having inner conductors for switching a connecting circuittherewithin, a base memberfor supporting and housing the switching mechanism, and an outer conductor disposed on a predetermined portion of a surface of the base member. Sincethe outer conductor is plated on the fixed base member, the circuit design of the switchiriz, device is simplified. This is advantageousfor a highfrequency circuit.

Itwill be understood from the foregoing description thatthis invention is applicable to another modified electric contact switching device. This invention may be applied to an electric contact switching device including a flat-shaped base member for supporting a switching mechanism having an inner conductor, a housing body which is mounted on or encloses the flat-shaped base member, and an outer conductor which is disposed on a predetermined su rface of the base member and/orthe housing body and connected to an external connecting member disposed on the device.

It should be understood that the above description is merely illustrative of th is invention and that many changes and modifications may be made by those skilled in the art without departing from the scope of the appended claims.

Claims

1. An electrical contact switching device for switching high frequency signals comprising:

a memberfor housing the switch; three conductors extending through a wall of the housing each p.-oviding an internal contact member forthe switch and disposed in aligmentwith each other, and an external contact memberfor making first external connections to the device, one internal 130 contact member constituting a common contact member disposed between the other two internal contact members, first and second movable contact blades within the housing member and disposed on opposite sides of the said aligned contact members, the first blade serving to make an internal electrical connection between a first pair of contacts comprising the common contact member and one of the othertwo internal contact members, and the second blade serving to make internal electrical connection between a second pair of contacts comprising the central contact memberand the other of the two contact members, the blades being movable in substantially opposite directions to breakthe internal electrical connection made by one blade and one pair of internal contact members and then make an internal electrical connection bythe other blade between the other pair of contact members; the blades being subsequently movable in the reverse direction to breakthethen existing internal electrical connection and remake thefirst-mentioned internal electrical connection; a conductive surfacewithin the housing which is contactable by each of the contact blades when not making an internal electrical connection between two of the internal contact members, the conductive surface being electrically connected to second external connecting means provided on the housing.

2. An electric contact switching device according to Claim 1, wherein the housing includes abase member supporting said fist conductor means, and the second conductor means is disposed on at least a predetermined surface of the base member.

3. An electric contact switching device according to claim 1 or2 wherein the said predetermined surface is formed on a portion of the housing made from a non-electrically conducting material.

4. An electric contact switching device according to Claim 1, 2 or3, wherein the first external connection means includes a lead member and a dielectric member supporting the lead member, the lead member being supported in the housing by the dielectric member.

5. An electric contact switching device according to any preceding claim, wherein the first conductor means is a switching mechanism including a stationary contact member and a movable contact blade member, and wherein the second conductor means is disposed on a predetermined surface of the housing so as to contactwith said movable contact blade member in a break circuit position.

6. An electric contact switching device according to anyone of Claims 1 to 5, which includes a conductive plate member and in which the housing includes a recessed portion for housing the first conductor means with the conductive plate member mounted on the recessed portion and connected to the second conductor means.

7. An electric contact switching device according to any preceding Claim wherein the housing is molded from insulating material.

8. An electric contact switching device according to anyone of Claims 1 to 6, wherein the housing is made from electrically conductive comprising a resin containing particles made from an electrically con- ducting material.

9. An electric contact switching device according to any preceding Claim wherein said second conductor means is a layer plated on said housing.

10. A device according to Claim 1 wherein the said blades are movable in substantially parallel planes into and out of contact with the appropriate pairs of contacts.

11. An electrical contact switching device accord- ing to Claim 2 wherein the said blades are movable in planes which are substantially parallel to the said line.

12. An electrical contact switching device according to Claim 1 and substantially as herein before described with reference to anyone of Figures 1 to 9.

13. A contact device according to any preceding claim wherein the second conductor means is in the form of a plate or layer connected to the second external connecting means.

ABSTRACT This invention relatesto an electrical contact switching device comprising a contact switching mechanism and a housing member supporting the electric switching mechanism, and more particularly to an improved switching device capable of switching high-frequency signals.

An electrical contact switching device for switching high frequency signals comprising:

a memberfor housing the switch; three conductors extending through a wall of the housing each providing an internal contact member forthe switch and disposed in alignmentwith each other, and an external contact memberfor making first external connections to the device, one internal contact member constituting a common contact member disposed between the othertwo internal contact members, first and second movable contact blades within the housing member and disposed on opposite sides of the said aligned contact members, the first blade serving to make an internal electrical connection between a first pair of contacts comprising the common contact member and one of the othertwo internal contact members, and the second blade serving to make internal electrical connection between a second pair of contacts comprising the central contact member and the other of the two contact members, the blades being movable in substantially opposite directionsto breakthe internal electrical connection made by one blade and one pair of internal contact members and then make an internal electrical connection bythe other blade between the other pair of contact members; the blades being subsequently movable in the reverse direction to breakthethen existing internal electrical connection and remake the firstmentioned internal electrical connection; a conductive surface within the housing which is contactable by each of the contact blades when not making an internal electrical connection between two of the internal contact members, the conductive surface being electrically connected to second external connecting means provided on the housing.

Printed in the United Kingdom for Her Majesty's Stationery Office, 8818935, 12185, 18996. Published at the Patent Office, 25 Southampton Buildings, London WC2A lAY, from which copies may be obtained.

GB 2 160 364 A 5