US3668575A

US3668575A - Electrical switch devices

Info

Publication number: US3668575A
Application number: US19378A
Authority: US
Inventors: Eric J Gargini
Original assignee: Communications Patents Ltd
Current assignee: Communications Patents Ltd
Priority date: 1969-03-14
Filing date: 1970-03-13
Publication date: 1972-06-06
Anticipated expiration: 1989-06-06
Also published as: AT300943B; SE373978B; ES192498Y; FR2038959A5; CH511508A; NL90728C; CA918717A; DE2011892B2; DE2011892A1; IL34155A0; GB1285351A; BE747343A; NL163360B; IL34155A; DE2011892C3; ES192498U; JPS4913305B1; NL204523A; NL7003600A; NL163360C

Abstract

A plurality of reed switch elements are radially disposed in an arcuate formation in special channels including electrostatic and electromagnetic shielding so that a movable magnet may be rotated by such means as a stepping motor to actuate single switches in sequence.

Description

United States Patent Gargini 1 June 6, 1972 [s41 ELECTRICAL SWITCH DEVICES 3,086,095 4/1963 R6656 ..335/206 3,505,869 4/1970 Crawford ..335/206 [72] Inventor: Eric J. Gargini, West Drayton, England [73] Assignee: Communications Patents Limited FOREIGN PATENTS OR APPLICATIONS 1,065,597 4/1967 Great Britain ..335/206 [22] 1970 1,059,340 2/1967 Great Britain ..335/206 [211 Appl. No.: 19,378

Primary Examiner-Harold Broome [30] Foreign Application Priority Data Atmmey Laurence Brown May 14, 1969 Great Britain ..l3,463/69 [57] ABSTRACT 52 us. (:1 335 140 335/206 A plurality reed Switch elements are radially diSPSed [51] Int. Cl. ..H01h 51/08 arcuate formation in Special channels including electrostatic 58 Field of Search ..335 152 206 140 151 301 and elecmmagnefic Shielding that a mvable magne may 33 5 5 5 5 66 be rotated by such means as a stepping motor to actuate single switches in sequence. [56] References Cited 22 Cl i 5 Drawing Figures UNITED STATES PATENTS 3,002,066 9/1961 Ketchledge et al. ..335/152 PATEHTEDJUH 6 I972 SHEET 10F 3 w v 0 I9 n J f W 0 0 3 n 0 fr C 3 W 0 A INVENTOR I E ic Garqmn ATTokNEY PATENTEDJUH 6 m2 SHEET 20F 3 INVENTOR BY 8H6 Gavglui ATTORNEY PATENTEDJUH s 1972 3. 668,575

SHEET 30F 3 INVENTOR I Evit J- Gav-3 ATTORNEY ELECTRICAL SWITCH DEVICES This invention relates to electrical switches and seeks to provide an improved form thereof. Switches in accordance with the present invention are particularly suitable for use as program selection switches in wired broadcasting systems.

An object of the present invention is to provide an electric switch which is magnetically operable and has a high degree of isolation between the switched signal paths.

According to one feature of the present invention, there is provided a switch device comprising a plurality of magnetically operable reed switch elements each of which is disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch element thereby simultaneously to provide both electrostatic and electromagnetic screening for said reed switch element.

According to a more specific feature of the invention there is provided a switch device comprising a plurality of magnetically operable reed switch elements radially disposed in an arcuate formation, each said element being disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch element thereby simultaneously to provide both electrostatic and electromagnetic screening for said reed.

Preferably the reed switch elements are arranged to extend radially from a common center.

Conveniently, the channel of conductive material may comprise a member of non-magnetically permeable material having secured thereto at spaced locations on one surface thereof, members of magnetically permeable material which define between them a channel the sides of which are of magnetically permeable material and the base of which is of non-magnetically permeable material. I

It may be convenient in an arrangement of the kind aforesaid, to arrange that one magnetically permeable member is common to two adjacent channels.

According to a further feature of the invention, a switch device of the kind described in the preceding paragraphs may include a panel of insulating material having formed thereon conductive tracks which define signal paths between a connection means and the reed switch elements each of said tracks being separated from an adjacent track by a further track which is arranged for connection to a point of zero signal potential. Y

Conveniently, the panel of insulating material has said conductive tracks disposed on one side thereof, while the other side of said panel has associated therewith a sheet of conductive material which is arranged for connection to said point of zero signal potential. Y

1 Further features and advantages of the invention will become apparent from the following description of one particular embodiment thereof given by way of example only with reference to the accompanying drawings.

FIG. 1 is a perspective view of a switch device in accordance with the present invention.

FIG. 2 is a similar perspective view of the switch device shown in FIG. 1 with part thereof removed so as to show the disposition of the reed switch elements.

FIG. 3 is an exploded view of the switch device shown in FIG. 2.

FIG. 4 is a detailed view of one face of one of the parts of the switch device shown in FIGS. 1 3, and,

FIG. 5 is a sectional view of part of FIG. 3.

The switch shown in FIG. 1 comprises a sandwich assembly of flat sheet members which comprise respectively a metallic support member 1 of non-magnetizable material, an insulating member 2, a member 3 formed of insulating material having associated with one face thereof a layer of conductive, nonmagnetizable material, a further insulating member 4, and a switching circuit member 5, formed of insulating material having on one face thereof conductive tracks which define signal paths between contact means 6 and reed switch elements not shown, and on the other face thereof a sheet of conductive, non-magnetizable material.

The members 1 5 are clamped together by means which include the securing clips 7. The contact means 6 are arranged for co-operation with fixed connector means which may be the so-called edge connectors for use with printed circuit boards. Two locating

slots

8 and 9 are located between the contact means 6 so as to prevent an incorrect association being established between said contact means and the fixed connector means.

The reed switch elements are covered by a cover member 10 which is formed of conductive, non-magnetizable material, a selected one of said reed switch elements being arranged to be actuated by the magnet 1 1, carried by the rotatable arm 12, which is secured to an actuating shaft of a stepping motor 14.

The reed switch elements are arranged to form a single pole multi-way switch, one connection of each reed switch element thus being common with a corresponding connection of each of the other reed switch elements. The commoned ends of the reed switch elements are connected to one of a pair of output terminals 15, the other of which is connected to a point of zero signal potential. The free ends of the reed switch elements are connected each by one of the conductive tracks on one face of the switching circuit member 5, to a corresponding contact position on the contact means 6 by the intermediary of which said free ends may be connected to corresponding sources of program signals. A further pair of terminals 16 is also carried by the member 3, said terminals being arranged to be connected to actuating means associated with the stepping motor 14. The terminals 15 and 16 are arranged to be connected to a remote signal utilization device such as may be used by a subscriber of a wired broadcasting network conveniently by means of two associated pairs of conductors, one of said pairs being formed by a pair of signal conductors connected to the output terminals 15, and the other of said pairs being formed by a pair of intersticial conductors associated with said signal conductors and connected to the terminals 16.

The arrangement of the reed switch elements is shown in FIG. 2. In this Figure the cover member 10, the magnet 11, and the arm 12, are removed to show the reed switch elements 17. Each reed switch element is disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch element. The channel of conductive material is formed by an aluminum ring 18 having secured thereto at spaced locations on one surface thereof members of magnetically permeable material in the form of iron wires 19. Each of the iron wires 19 is common to two adjacent ones of the reed switch elements 17. As will be seen from FIG. 2 the reed switch elements are disposed in an arcuate formation, extending radially from a common center defined by the axis of the actuating shaft 13. In this way the magnet 1 1 shown in FIG. 1 may be moved over each of the reed switch elements 17 in the same relative position. This position may be that which provides the maximum sensitivity of response to the magnet by the reed switch elements.

The relative disposition of the various components of the assembly shown in FIGS. 1 and 2 is shown in more detail in FIG. 3. The metallic support plate 1, which may conveniently be formed of aluminum, has secured thereto the insulating member 2 which carries thereon the aluminum ring 18. The ring 18 is formed with a plurality of notches on its inner and outer peripheries in which the limbs of U" shaped iron wires 19 may be located, the ends 21 of these wires being arranged to lie flush with the underside 22 of the ring 18 thereby to retain them into position. The ring 18 is secured to the insulating member 2 by means for example, of screws passing I through the

respective holes

23, 24.

The member 3 is provided with an aperture 25 which has a diameter greater than that of the aluminum ring 18 so that when placed adjacent the insulating member 2 having the ring 18 secured thereto, said ring 18 partly projects through the aperture 25. Additionally, around the periphery of the aperture 25 there are provided clearance holes 26 which serve to accommodate, when the switch device is in its assembled condition, the ends of the connecting wires of the reed switch elements 17. One face of the member 3 is provided with a layer of conductive, non-magnetizable material 27. Conveniently, the member 3 and layer 27 are formed by a single sided copper epoxy laminate, such asmight be utilized for the construction of a so-called printed circuit panel.

The member 3 is separated from the member 5 by means of the further insulating member 4 which has therein an aperture 28 and clearance holes 29 similar to the aperture and

holes

25 and 26 provided in the member 3. The switching circuit member 5 is formed of insulating material and has on one side thereof a layer of conductive, non-magnetizable material 30, while on the other side has a plurality. of conductive tracks, shown more clearly in FIG. 4, which extend each between the respective one of the apertures 31, into which pass a connecting wire 32 of a reed switch element 17, and part of one of the contact means 6. In order to provide effective screening between the conductive track associated with the aperture 31 the layers of conductive,

non-magnetizable material

27 and 30 are arranged to be connected to a point of zero signal potential. In addition, each conductive track which extends between an aperture 31 and part of one of the contact means 6 is arranged to be separated from each of the adjacent tracks extending between others of the aperture 31 and the contact means 6' by a conductive track which is also arranged to be connected to a point of zero signal potential. The other connecting wires 33 of the reed switch elements 17 are electrically connected to a common point formed by a conductive surface on the face 34 of the disc 35. To this face 34 there is secured a connecting pin 36 which is arranged to extend through the assembly so as to be accessible from the outer face of the member 1. The conductive area of the face 31 is arranged to be spaced from the insulating member 2 by means of an insulating shim 37.

. The cover member is formed of a conductive, non-magnetizable material and serves the double purpose of protecting the assembly of reed switch elements 17 and also providing an eddy-current electromagnetic brake so that the'magnet 11 has applied thereto a retarding force as it is moved from a position adjacent one reed switch element to a position adjacent the next reed switch element, which braking efiect serves to minimize the possibility of the magnet over-travelling when moved from one position to another.

The magnet 11 is arranged to be rotatable by means of an electric stepping motor 14 which includes a solenoid 38 which is arranged to be energized by electric current signals-applied to the terminals 16. When energized, the solenoid 38 is effective to move an annature' 39 against the bias of the spring 40 so as to cause the tooth 41 to engage the ratchet 42. Each energization of the solenoid 38 is effective, to rotate the ratchet 42 by one position, said positions being defined by a spring detent member 43 (not shown) arranged to bear against the teeth of the ratchet 42. The armature 39 carries a further tooth 44 which is arranged to prevent over-travelling of the ratchet 42 when it is advanced by the tooth. The ratchet 42 is effective to drive the actuating shaft 13 to which the rotatable arm 12 carrying the magnet 11 is secured as shown in FIG. 1. I

The conductive tracks on the switching member 5 which extend between the aperture 31 and corresponding contact positions on the contact means 6 are shown in FIG. 4. In this figure the tracks 45 extend from the apertures 31 to which are secured, for example by soldering, one of the connecting wires 32 (not shown) of the reed switch elements 17. Between each adjacent track 45 there is arranged an auxiliary track guard conductor 46 which extends between two adjacent ones of the apertures 31 approximately parallel with the tracks 45 which are associated therewith to a contact position on the contact means 6 which lies between the contact positions to which said conductive tracks 45 are connected. The fixed connector means with which the contact means co-operate are provided with connections which serve to establish contact between the conductive strips 46 and a point of zero signal potential so that said tracks 46 form a screening member between adjacent ones of the tracks 45. FIG. 4 also shows the common connection which is established between the connecting wires 33 of the reed switch elements 17 and the connecting pin 36 carried by the disc 35. This common connection with the pin 36 is effected by means of the annular conductive area 47 to which said pin and said wires 33 are connected, for example by soldering.

FIG. 5 shows a cross-section of part of the aluminum ring 18 showing the arrangement of the iron wires 19 and reed switch elements 17. As will be seen from FIG. 5 the aluminum ring 18 is a relatively flat member and the iron wires 19 are secured thereto at spaced locations on one surface 19 thereof. Two adjacent ones of the iron wires 19 form, in association with the aluminum ring 18, a channel, the sides of which are of magnetically permeable material and the base of which is of nonmagnetically permeable material. In the channel so defined there is arranged a reed switch element 17. The channel in which the reed switch element 17 is disposed provides electrostatic screening therefor so as to define a form of co-axial signal conductor having a good impedence match to the conductive tracks formed on the switching circuit member 5 Additionally, the provision of the magnetically permeable members which define part of this channel serve to concentrate the magnetic field of the magnet 11 when this magnet is disposed adjacent a reed switch element 17. This concentration of the magnetic field has the efiect of improving the sensitivity of the particular reed switch element 17 concerned and at the same time minimizes the likelihood of an adjacent reed switch element being magnetized and thus actuated. It will be observed that each of the iron wires 19 is common to two adjacent channels and reed switch elements 17.

It will be appreciated that the channel of non-magnetically permeable and magnetically permeable material may be formed in other ways, for example, the channels may be formed in an aluminum casting the magnetically permeable members being positioned therein prior to the casting so as to form an integral part thereof.

lclaim:

l. A switch device comprising a plurality of magnetically operable reed switch elements placed side by side, each of which is disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch elements and extending between adjacent switch elements thereby simultaneously to provide both electrostatic and electromagnetic screening for said reed switch element, non-magnetically permeable metallic plate members disposed on opposite sides of said switch elements, and means moving a magnet from one switch element to another with one of said plate members between it and said switch elements.

2. A switch device as claimed in claim 1 comprising a plurality of magnetically operable reed switch elements radially disposed from a common center in an arcuate formation like the spokes of a wheel.

3. A switch device as claimed in claim 1 wherein the members of magnetically permeable material comprises iron wires.

4. A switch device as claimed in claim 1 in which one said plate member of non-magnetically permeable material comprises an aluminum ring having secured thereto at spaced locations on one surface thereof said members of magnetically permeable material.

5. A switch device as claimed in claim 4 in which the magnetically permeable members comprise U-shaped iron wires and the aluminum ring is formed with a plurality of notches on its inner and outer peripheries in which the limbs of U shaped iron wires are located, the ends of these wires being arranged to lie flush with the underside of said ring thereby to retain them in position.

6. A switch device as claimed in claim 1 which includes a panel of insulating material having formed thereon conductive tracks which define signal paths between a connection means and the reed switch elements, each of said tracks being separated from an adjacent track by a further track which is arranged for connection to a point of zero signal potential.

7. A switch device as claimed in claim 6 wherein the panel of insulating material has said conductive tracks disposed on one side thereof and the other side of said panel has associated therewith a sheet of conductive material which is arranged for connection to said point of zero signal potential.

8. A switch device as claimed in claim 6 wherein the panel of insulating material, said conductive tracks and said sheet of conductive material are formed from a double sided printed circuit panel.

9. A switch device as claimed in claim 6 in which one of the plate members is an aluminum ring and the panel of insulating material is provided with an aperture to receive said aluminum rmg.

10. A switch device as claimed in claim 9 in which periphery of said aperture is provided with clearance holes which serve to accommodate the ends of connecting wires of the reed switch elements.

11. A switch device as claimed in claim 1 wherein the magnet is a permanent magnet and is carried by a rotatable arm secured to an actuating shaft.

12. A switch device as claimed in claim 11 wherein the actuating shaft is arranged to be rotatable and a stepping motor driving said shaft.

13. A switch device as claimed in claim 12 wherein said electric stepping motor includes an operating solenoid and a movable armature which carries a driving tooth and a locking tooth whereby said ratchet is prevented from moving by more than one step for each actuation of the operating solenoid.

14. A switch device as claimed in claim 1 wherein one of said plate members is disposed as a cover member arranged to act as an eddy-current electromagnetic brake so that the magnet is subjected to a retarding force as it is moved from a position adjacent one reed switch element to a position adjacent the next reed switch element which braking effect serves to minimize the possibility of the magnet over-travelling when moved from one position to another.

15. A switch'device as claimed in claim ll wherein the reed switch elements are arranged to form a single pole multi-way switch. I

16. A switch device as claimed in claim l5'wherein one connection of each reed switch element is common with a corresponding connection of each of the other reed switch elements.

17. A switch device as claimed in claim 16 in which the commoned ends of the reed switch elements are connected to one of a pair of output terminals, the other of which is connected to a point of zero signal potential.

18. A switch device as claimed in claim 15 in which a set of conductive tracks is provided and contact means, the free ends of the reed switch elements are connected each by one of the conductive tracks to a corresponding contact position on said contact means by the intermediary of which said free ends may be connected to corresponding sources of program signals.

19. An electric switch device which comprises a plurality of magnetically operable reed switch elements arranged radially about a common axis for actuation by a magnet rotatably mounted for movement about said common axis and in which said reed switch elements include magnetic screening elements separating each reed switch from its neighbors by members of magnetizable material arranged between the two adjacent switches comprising in combination a platform of conductive, non-magnetizable material forming an electrostatic screening element, said magnetic screening elements being located adjacent said platfonn and forming a structure therewith comprising a plurality of channels of conductive material each of which includes two magnetically permeable members arranged one on each side of a reed switch element, and electrical connection structure in each channel defining with its associated reed switch element and at least some of the screening elements a form of co-axial transmission line.

20. A switch device according to claim 19 further characterized in that the platform of conductive, nonmagneticable material and a circuit connecting said conductive material to a point of zero signal potential.

21. A switch device according to claim 20 further characterized in that the other side of said panel of insulating material has conductive tracks disposed thereon which define signal paths to the reed switch elements, each of said tracks being separated from an adjacent track by a further guard conductive track, and means connecting said guard track to said point I of zero signal potential.

22. A switch device according to claim 19 further characterized in that a cover member of conductive, nonmagneticable material is interposed between the reed switch elements and the magnet to serve as an eddy current electromagnetic brake so that the magnet is subjected to a retarding force as it is moved from a position adjacent one reed switch element to a position adjacent another reed switch element.

I l i l i

Claims

1. A switch device comprising a plurality of magnetically operable reed switch elements placed side by side, each of which is disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch elements and extending between adjacent switch elements thereby simultaneously to provide both electrostatic and electromagnetic screening for said reed switch element, nonmagnetiCally permeable metallic plate members disposed on opposite sides of said switch elements, and means moving a magnet from one switch element to another with one of said plate members between it and said switch elements.

5. A switch device as claimed in claim 4 in which the magnetically permeable members comprise U-shaped iron wires and the aluminum ring is formed with a plurality of notches on its inner and outer peripheries in which the limbs of ''''U'''' shaped iron wires are located, the ends of these wires being arranged to lie flush with the underside of said ring thereby to retain them in position.

9. A switch device as claimed in claim 6 in which one of the plate members is an aluminum ring and the panel of insulating material is provided with an aperture to receive said aluminum ring.

15. A switch device as claimed in claim 1 wherein the reed switch elements are arranged to form a single pole multi-way switch.

16. A switch device as claimed in claim 15 wherein one connection of each reed switch element is common with a corresponding connection of each of the other reed switch elements.

19. An electric switch device which comprises a plurality of magnetically operable reed switch elements arranged radially about a common axis for actuation by a magnet rotatably mounted for movement about said common axis and in which said reed switch elements include magnetic screening elements separating each reed switch from its neighbors by members of magnetizable material arranged between the two adjacent switches comprising in combination a platform of conductive, non-magnetizable material forming an electrostatic screening element, said magnetic screening elements being located adjacent said platform and forming a structure therewith comprising a plurality of channels of conductive material each of which includes two magnetically permeable members arranged one on each side of a reed switch element, and electrical connection structure in each channel defining with its associated reed switch element and at least some of the screening elements a form of co-axial transmission line.

20. A switch device according to claim 19 further characterized in that the platform of conductive, non- magneticable material and a circuit connecting said conductive material to a point of zero signal potential.

21. A switch device according to claim 20 further characterized in that the other side of said panel of insulating material has conductive tracks disposed thereon which define signal paths to the reed switch elements, each of said tracks being separated from an adjacent track by a further guard conductive track, and means connecting said guard track to said point of zero signal potential.

22. A switch device according to claim 19 further characterized in that a cover member of conductive, non- magneticable material is interposed between the reed switch elements and the magnet to serve as an eddy current electromagnetic brake so that the magnet is subjected to a retarding force as it is moved from a position adjacent one reed switch element to a position adjacent another reed switch element.