IL34155A - Electrical switch devices - Google Patents

Description

IMPROVEMENTS IN AND RELATING- TO ELECTRICAL SWITCH DEVICES This invention relates to electrical switches and seeks to Ά. provide an improved foOT thereof. Switches in accordance vd.th the present inention are particularly suitable or use as programme selection switones in wire broadpasting systems.

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

According to tile invention, there is provided a switch device comprising a plurality of magnetically operable reed switch elements placed side by side, eac o which is disposed in a channel of conductive material which includes two magnetically permeable members arranged one on each side of the reed switch elementsand extending between adjacent switch elements thereby simultaneously to provide both electro-static and eleotro-flagnetic screening or said reed switch element, non½agnetLoally 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.

According to a more specifid feature of the invention there is provided a switch device comprising a plurality of magnetically operable reed switch elements radially disposed from a common centre in a arcuate formation, each said element being disposed in a channel of conductive material which includes two magnetically permeable members arranged one o each side of the reed switch element thereby simultaneously to provide both electro-static and electro-magnetic screening for said reed.

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

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 whic are of It may be convenient in an arrangement of the kind aforesaid, 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.

Conveniently, the panel of insulating material has said conductive tracks disposed on one side thereof, whilst 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.

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. is a detailed view of one face of one of the parts of the switch device shown in Figs. 1 - 3i-and, Fig. 5 s 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 formed of insulating material having associated with one face thereof a layer of conductive, non-magnetisable material, a further insulating member and a switching circuit member i 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-magnetisable 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-magnetisable material^ a selected one of said reed switch elements being arranged to be actuated by the magnet 11, carried by the rotatable arm 12, which is secured to an actuating shaft of a stepping motor l;t.

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 programme signals. A further pair of terminals 16 is also carried by the member 3i said terminals being arranged to be terminals 15 and 16 are arranged to be connected to a remote signal)^ utilisation 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 ireed 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 1?. 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 aluminium 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 1?. As will be seen from Fig. 2 the reed switch elements are disposed in an arcuate formation, extending radially from a common centre defined by the axis of the actuating shaft 13. In this way the magnet 11 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 asseraHy shown in Figs. 1 and 2 is shown in more detail in Fig. J>. The metallic support plate 1, which may conveniently be formed of aluminium, has secured thereto the insulating member 2 which carries thereon the aluminium ring 18. The ring l8 is formed with a plurality of notches on its inner and outer peripheries in which the limbs of 'ϋ' shaped iron wires 19 may be located, the ends 21 of these wires being arranged them into position. The ring 18 is secured to the insulating member 2 by means for example, of screws passing through the respective holes 23, 2. , The member 3 is provided with an aperture 5 which has a diameter greater than that of the aluminium ring 18 so that when placed adjacent the insulating member 2 having the ring 18 secured thereto, said ring l8 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-magnetisable material 27· Conveniently, the member 3 and layer 27 are formed by a single sided copper epoxy laminate, such as might be utilised 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 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-magnetisable material 30, whilst on the other side has a plurality of conductive tracks, shown more clearly in Fig. , 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 screen -ing between the conductive track associated with the aperture 31 the layers of conductive, non-magnetisable 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 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 3^ of the disc 35» To this face 3^ 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 s arranged to be spaced from the insulating member 2 by means of an insulating shim 37· The cover member 10 is formed of a conductive, non-magnetisable material and serves the double purpose of protecting the assembly of reed switch elements 17 and also providing an eddy-current electro-magnetic 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 effect serves to minimise 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 l^ which includes a solenoid 38 which is arranged to be ©nergised by electric current signals applied to the terminals l6. When energised, the solenoid 38 is effective to move an armature 39 against the bias of the spring so as to cause the tooth l to engage the ratchet 2. Each energisation of the solenoid 38 is effective to rotate the ratchet z by one position, said positions being defined by a spring detent member hj> (not shown) arranged to bear against the teeth of the ratchet Za The armature 39 carries a further tooth t which is arranged to prevent over-travelling of the ratchet hZ when it is advanced by the tooth 2. The ratchet Z 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.

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. 0 In this Figure the tracks $ 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 k5 there is arranged an auxiliary track 46 which extends between two adjacent ones of the apertures 31 approximately parallel with the tracks k$ which are associated therewith to a contact position on the contact means 6 which lies between the contact positions to which said conductive tracks 4-5 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 6 and a point of zero signal potential so that said tracks S form a screening member between adjacent ones of the tracks $m Fig. k also shows the common connection which is established between the connecting wires 33 of the reed switch elements 1? 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 7 to which said pin and said wires 33 are connected, for example by soldering.

Fig« 5 shows a cross-section of part of the aluminium ring l8 showing the arrangement of the iron wires 19 and reed switch elements 17· As will be seen from Fig, 5 the aluminium ring l8 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 aluminium ring l8, a channel, the sides of which are of magnetically permeable material and the base of which is of non-magnetically 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 electro-static screening therefor so as to define a form of co-axial signal conductor having a 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 1?. This concentration of the magnetic field has the effect of improving the sensitivity of the particular reed switch element 17 concerned and at the same time minimises the likelihood of an adjacent reed switch element being magnetised 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 aluminium casting the magnetically permeable members being positioned therein prior to the casting so as to form an integral part thereof.

Claims (1)

1. WHAT WE CLAIM IS A switch comprising a plurality of magnetically operable reed elements placed side by each of which is disposed in a channel of conductive material whic includes two magnetically permeable members arranged on on each side of the reed switch elements and extending between adjacent switch elements thereby simultaneously to provide both screening for reed switch permeable metallic plate members disposed on opposite sides of said switch and a from one switch element to another with of said plate members between it and said switch A switch device as claimed in claim comprising plurality of magnetically operable reed switch elementn radially disposed from a common centre in an arcuate the spokes of a wheels A switch device as claimed in claim 1 wherein the members of magnetically permeable material comprises iron A switch device as claimed In claim 1 in which said plate o permeable material comprises an aluminium ring having secured thereto at spaced locations on sur thereof said members of magnetically permeable switch device as claimed in any of the foregoing claims which the magnetically comprise iron and the aluminium ring is formed with a plurality on its inner and outer peripheries in which the limbs of shaped iron wires are the ends of these wires being arranged to lie flush with the underside of said ring thereby to retain them in device as claimed in any of the foregoing claims which includes a panel of insulating material having formed thereon conductive tracks which define signal a connection means and the reed switch each of said tracks being separated by a further track from an adjacent is arranged for connection to a point of zero signal A switc device as claimed in claim 6 wherein the panel of insulating material has said conductive tracks disposed oh side thereof and the other of said panel has associated therewith a sheet of conductive material which is arranged or connection to said point of signal A device as claimed in claim 6 or 10 wherein the panel of insulating said conductive and said sheet of conductive material are formed from a double printed circuit A switch device as claimed in of claims 6 to 8 in which on of the plate members is an aluminium ring and panel o insulating material is provided with an aperture to aluminium A switch device as claimed in claim 9 in which periphery of said aperture is provided with clearance holes serve to the ends of of the reed switch A switch device claimed in claim 1 wherein the magnet is a permanent magnet and is carried by a rotata le arm secured to an actuating A switch devic claimed in claim 11 wherein the actuating is arranged to be rotatable and a s driving A switch as claimed in claim 12 wherein electric stepping motor includes an operating solenoid and a movable armature carries a driving and a locking tooth whereby said ratchet is prevented from moving b more than one step each actuation of the operating solenoid 1 switch deyice as claimed in claim 1 wherein one of said plat members is disposed as a cover member arranged to act as an netic so that the magne subjected to a retarding force as it is moved from position adjacent one reed switch element to a position adjacent the next reed switch element which effect serves to minimise the possibility of the magnet when moved from one position to A switch device as claimed in any of the foregoing claims where n the reed switch elements are arranged to form A switch device as claimed in claim 15 wherein one connection of each reed switch element is common with a corresponding of of the other elemen Δ device as claimed in claim 16 in which the commpned ends of the switch elements are connected to one of a pair of output the other of which is connected to a point of zero signal A switch device as claimed in any of the claims in whic a of conductive tracks is provided and contact 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 of which said free ends may be connected to corresponding of programme An electric switch device comprises a plurality of magnetically operable switch elements ί 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 neighbours by members of magnetisable material between the adjacent switches comprising in combination a platform of material forming an electrostatic screening said magne c 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 of a reed switch and electrical connection structure each channel defining with its associated reed switch element and at least some of the screening elements a form of transmission A switch device according to claim 19 further characterised in that the platform of magneticable material and a circuit connecting said conductive material to a point of zero signal A switch device according to claim 20 further characterised that the other side of said panel of insulating material has conductive tracks disposed thereon which define signal paths to the reed switch each of said tracks being separated from an adjacent track by a further guard conductive and means connecting said guard track to said point of zero signal A switch device according to claim 19 further characterised in that a cover member of magneticable material is interposed between the reed switch elements and the magnet to serve as an eddy current brake so that the magnet is subjected to a retarding as it is moved from a position adjacent one reed switch elemen to a positio adjacent another switch element CLAIM A magnetically operable reed switch elements placed side by each of is disposed in a channel of conductive material which includes two magnetically permeable members one on each side of reed switch elements and extending between adjacent switch elements thereby simultaneously to provide bot and screening reed switch element permeable metallic plate members disposed on opposite sides of switch and means moving a from one element another with one of said plate members between it and said switch A switch as claimed in claim 1 comprising a plurality of magnetically operable reed switch elements radially disposed from a common centre in an arcuate like the spokes of a A switch device as claimed in claim 1 the of magnetically permeable material comprises iron wires A switch device as claimed in claim 1 in which one said plate member of permeable material comprises an aluminium ring having secured thereto at locations on one surface thereof members of magnetically permeable switch device as claimed in any of the foregoing claims the magnetically permeable insufficientOCRQuality