US2526804A - Electrical contact assembly - Google Patents

Description

Oct. 24, 1950 R. E. H. CARPENTER ELECTRICAL CONTACT ASSEMBLY 4 Sheets-Sheet 1 Filed Feb. 27, 1946 Inventor MW A Harney Oct. 24, 1950 R. E. H. CARPENTER 2,526,804

ELECTRICAL CONTACT ASSEMBLY Filed Feb. 27, 1946 v 4 Sheets-Sheet 2 A ltorney Oct. 24, 1950 R. E. H. CARPENTER ELECTRICAL CONTACT ASSEMBLY Filed Feb. 27, 1946 4 Sheets-Sheet '3 A [lor/ley 0d- 24 1950v R. E. H. CARPENTER A2,526,804

ELECTRICAL comcm Asslzmsuf- Filed Feb. 27, 1946 v 4 sagas-shan 4 F/GQQ.

B WV I Attorney Patented ct. 24, 1950 ELECTRICAL CONTACT ASSEMBLY Rupert Evan Howard Carpenter, South Croydon, England Applioation'February 27, 1946, Serial No. 650,617 In Great Britain March 6, 1945 Il Claims.

This invention relates to the mounting of electrical contacts and its chief object is to secure the simultaneous opening or closing or both of two or more pairs of electrical contacts, such as those used in polarised or other relays. The invention is particularly suitable for use in relays having a pair of moving contacts which alternatively engage one or other of two pairs of contacts which can be regarded as relatively fixed contacts and which therefore effect the same operation as a double pole change-over switch. The invention, however, is also applicable to other relays with multiple contacts, such as, for example, those required to open or close a number of circuits simultaneously.

According to the presen-t invention, one of each pair of co-operating contacts is so mounted that movement imparted to the one contact of a pair upon closing of the contacts results or tends to result in a movement in the opposite sense of another contact of the same kind, or of more than one such contact in the apparatus, and the relative position of these moved contacts is then maintained frictionally.

For clearness of description, any two contacts which are brought into or out of engagement, such as the movable armature contact and a side contact of a polarised relay, will be referred to respectively as an active and a passive contact. Thus, on the iirst operation of the device, after setting up, one passive contact will normally be reached by its co-operating active contact earlier than the other or others, and consequently this co-operating pair of contacts will close rst, The

motion thus imparted to that passive contact,

however, causes the other passive contact of a pair, or the other passive contacts to move towards their corresponding active contacts, and this motionl will only cease in each case on the meeting of each pair of active and passive contacts. Then all thev passive contacts will be aligned with respect to their co-operating active contacts, and all pairs of active and passive contacts will be pressed together with approximately the same force, On the active contacts, which are all assumed to move together, being moved in the opposite direction, all pairs of active and passive contacts tend to separate at the same instant of time. Moreover, since the relative positions of the passive contacts are maintained by friction, the second and succeeding closures of the contacts will be nearly simultaneous also, and the pressures between the passive contacts and the (3o-operating active contacts will remain equalised which is a state ofailairs which can 2 not beattained by independent mounting of the individual contacts on springs.

In order that the invention may be readily understood and easily carried into effect, some forms of the invention will now be described with reference to the accompanying drawings, in which:

Figure l is a front elevation of a polarised telegraph type of relay to which the invention is applied;

Figure 2 is a plan of the same;

Figure 3 is a rear elevation;

Figure 4 is a vertical section to an enlarged scale taken on the line IV-IV in Figure r2; and

Figure 5 is an enlarged perspective view ofthe contact arrangements with the passive contacts spread from the armature which bears the active contacts;

Figure 6 is a perspective View of a modied arrangement in which the invention is applied to the mounting of four passive contacts;

Figure 7 is an elevation looking on the face of a mounting for three passive contacts.

Figure 8 is a View in elevation of the left terminal pillar of a form of relay using a contact supporting bar formed of insulating material, the insulating bar and certain other parts being shown in vertical section;

Figure 9 is a view to the'right of Figure 8 with the armature removed; and

Figure 10 is a perspective view of Figure 8 with the armature removed.

Referring to Figures 1 to 5, the contacts are those of a double pole change-over or double` throw relay which is a polarised relay having the magnetic circuits and the mounting of the armature arranged as in applicants U. S. Patent 2,412,123. The coil for the reversals current'S, the magnets ll, I2, the magnetic limbs 2, 3, the pole pieces 6, 1, the armature l0, and the armature mounting springs 25, correspond to the same parts in the said Patent 2,412,123, in which those parts are similarly numbered. Near one end the armature I0 carries a pair of contacts 30, 3l which project from its two opposite iiat faces; they are-insulated from one another, and as best seen in Figure 5, are connected by angle strips 32 33 and iiexible connector strips 32a and 33a to terminal strips or tags 34, 35, which are mounted on the frame of the instrument. It can be seen that the contacts 30, 3l are spaced a short distance apart and are placed side by side so that they are equidistant from the pivotal axis of the armature Ill. These form.. the active contacts and they engage a pair of side contacts 36, 31 when the upper end of the armature moves to the left, as seen in Figure 1, and they engage a pair of contacts 38, 39 when the upper end of the armature moves to the right in Figure 1. The pair of passive contacts 36, 31, or 38, 39 on each side are mounted near opposite ends of a short bar 40, 4| of rigid insulating material, and pivoted at its centre about a vertical axis which is therefore parallel to the contact bearing faces of the armature I0. The pivotal arrangement is shown in Figure 4 where one of the bars 40 has a pin 42 forced into a vertical bore in the bar 40, and passes through holes in tongues 43, 44 secured to the sheet metal pieces 45 to engage frictionally the upper and lower surfaces of the bar 40. A coiled compression spring 46 is introduced around the pin 42 between its head 41 and the lower tongue 44. Thus, as the pin 42 is tight in the bar 40, this spring forces the bar 40 down into contact with the ton-gue 44, and while the bar 40 and the pin 42 can turn about the vertical axis of the pin, friction is exerted by the tongue 44 to hold the bar 4Q in any angular position into which it may be pushed.

The sheet metal pieces 45 are in eiTect flat springs riveted at their lower ends to contact suD- porting plates 48, and at their upper ends at 49, rubbing on the top edges of the plates 48, thereby providing compliant members with damping means for vibrations of the armature in accordance with applicants U. S. Patent No. 2,219,222.

The plates 48 are resiliently mounted at their lower ends on tags 58 and the adjustment of the passive contacts 36, 38 is effected by resiliently springing the plates 48 inwards from the pillars 5|. For that purpose, the plates 4S are engaged by the points of the adjustment screws 52.

The passive contacts 36, 31, and 38, 38 are, therefore, mounted so that they can move through small angles about the axes of the pins 42, but this angular movement is controlled by the friction between the bars 40, 4| and the tongues 44. These contacts 36 and 31 or 38 and 39, are mounted with the members of each pair spaced apart by the same distance as the active contacts 30, 3| so as to co-operate with the latter.

In an alternative construction the hars 40, 4| may be made of insulating material with metal foils on opposite faces, and the contacts 36 and 31 or 38 and 39 connected each to one of the foils so that connection may be made to them through the frictional joints between the bar 40 or 4| and the tongues 43, 44 which would then be insulated from one another. This alternative construction is illustrated in Figures 8 to 10 and will be described iny greater detail hereinafter, arrangement the bar 40 or 4| constitutes a rocker bar bearing contacts 36, 31 or 38, 38, which if one of a pair moves, the other is caused to move in the opposite sense so that when the passive contacts, for example, 36, 31, are engaged by the armature or active contacts 38, 3|, the passive contacts are self-aligned with respect to the active contacts.

The connections to the contacts 36, 31, and 38, 3S are made by flexible insulated wires 53 which on either side of the armature are taken down through short lengths of insulating sleeving 54 and are secured to terminal tags 55 which are carried in the same insulating mounting as the tags 50.

In Figure 6, an arrangement is shown where there are four passive contacts 55 mounted in pairs on separate rocker bars 51 which in this instance are shown to be vertical. The bars 51 are gripped in spring fingers 5S through which hori- In either zontal pivot pins 59 pass, the pins 59 being xed in the bars 51. The rocker bars 51 can yield in the spring ngers 58 and turn through small angles about the pivot pins 59 so that the passive contacts 56 of each pair simultaneously move in opposite senses. The spring iingers 58 are formed in two pairs each constituted by a loop of spring metal such as copper beryllium, and these loops are secured to a horizontal rocker bar 40 which corresponds exactly to the bar 40 in Figures l to 5. In this case, however, the rocker bar 40 is gripped by the spring fingers of a sheet metal loop 60 through which a pin 6| fixed in the rocker bar 40 passes, so that as in. Figures 1 to 5, the rocker bar 40 can turn about the vertical axis of the pin 6|. The rocker bar 40 is mounted at the upper end of a plate 48 which corresponds to the supporting plate 48 in Figures 1 to 5, and except that the armature must have four contacts, the rest of the relay may be constructed as in Figures l to 5 and consequently functions as a four-pole changeover relay.

In Figure '7, a triple pole arrangement is illustrated, the passive contacts 62 being mounted at the corners of an equilateral triangle on the face of a cylindrical member 53 of insulating material mounted parallel to the contact carrying face of the armature of the relay and which is made hollow with an annular wall for the sake of lightness. The disc 63 is adjustably gripped by the points of two screws 64 which pass through a gimbal ring 65 which can yield slightly, The screws 64 are threaded in nuts 66 welded to the inside of the ring 65, and the screws are provided with lock nuts 61. The gimbal ring 65 is also engaged by the points of pivots 68 which project outwardly from the arms of a forked bracket 69. This bracket may be a continuation of a plate such as the plate 48 in Figures 1 to 5, or may be xed to the upper end of such a plate. The pivots 68 are not in themselves adjustable, but the frictional action of them can be adjusted by adjustment of the screws 64 because the adjustment of the screws 64 slightly distorts the gimbal l ring 65 and modies the frictional engagement of the pivots 68 with that ring.

Figures 8 to 10 illustrate the alternative construction referred to above in which the bar for supporting the passive contacts is formed of insulating material. In this arrangement, the bar |48 (corresponding to the bar 40 in Figures 1 to 5) is formed of insulating material and is provided with sheet metal pieces |56 and |51 on the upper and lower faces. These metal sheets have extensions |58 and |59 bent against the iront face of the bar |40 and are connected to the passive terminals |36 and |31, respectively. The frictional joint for supporting the bar and for effecting electrical connections to the passive contacts are formed by pivot pins |60 and |6| supported in horizontal portions of tongues |43 and |44 which are insulated from one another. The pointed ends of pivot screws |60 and |6| are seated in bearing sockets formed in metal sheets |56 and |51 so that the bar |40 can turn on the pivots under the friction due to the pressure of the adjustable pivot screw |60. The bracket |43 is resiliently supported on a terminal strip |50 and the contacts are set, as in the case of Figures 1 to 5, by the screw |52 threaded in the upper end of pillar' |5| and bearing on the bracket |43. The bracket |44 has a flexible connection to a terminal strip |55 so that connection to the contacts |36 and |31 is completed through the pivotal joints and the pins |60 and |6|, The bracket |44 is supported from the bracket |43 byrmeans of a screw |62 passing through clearance holes in the brackets and in insulating washers or spacer disks |63.

In the above examples, the equalising system has been described as applied to the passive contacts, but clearly the roles of the active and passive contacts in this connection may be reversed; however, it is usually preferable to avoid the extra mass involved in such means on the moving parts.

It will be appreciated that the friction provided for maintain-ing the adjustable contacts in the adjusted position should be as great as possible subject to the fact that the adjustment must occur under the smallest operating forces exerted by the moving contacts. Any connecting wires from the contacts must be suiciently exible to ensure that the adjustable contacts will not be prevented from remaining in the position. in which they are set. The adjustable contacts and the rocker bar or other member carrying them should have a minimum moment of inertia and if mounted with compliance and provided with damping means according to my U. S. Patent 2,219,222 dated October 22, 1940, should be as light as possible. It will also be apparent that an outstanding advantage of the invention is that a single adjusting means only need be used for advancing and retracting all the adjustable contacts which will usually be the passive contacts; thus, the adjustment of such a relay or other apparatus is rendered no more difficult than that of anapparatus having a single side contact on each side of the armature.

I claim:

1. A mounting assembly for electrical contacts, comprising two pairs of contacts vmounted for relative movement to permit of opening and closing of said contacts, a rocker member carrying one of said pairs of contacts and pivotally mounted about an axis to permit of movement of the contacts carried thereby in opposite senses to and from the respective contacts of said other pair, frictional means engaging said rocker member to maintain same and the contacts carried thereby in positions determined by the engagement of said two pairs of contacts, and a pair of conductive mounting means carried on opposite sides of said rocker member, said pair of mounting means being insulated from each other and forming the pivotal mounting for said rocker member for connecting the contacts on said rocker member with a pair of xed terminals.

2. In a double-throw switch, the combination of an armature mounted to move between two positions, a pair of active contacts carried by said armature on one side thereof, a second pair of active contacts carried by said armature on the opposite side thereof, two pairs of passive contacts arranged on opposite sides of said armature and in positions to be engaged respectively by said pairs of active contacts carried by said armature, a rocker member arranged on one side of said armature and carrying in insulated relation the contacts of one pair of said pairs of contacts and being adjustable in position by engagement with the cooperating pair of contacts, frictional means operative to maintain said rocker member in adjusted position, a second rocker member arranged on the opposite side of said armature and carrying in insulated relation the contacts of another pair of contacts and being adjustable in position by engagement with the cooperating pair of contacts, frictional means to maintain the second rocker member in adjusted position, a pair of metallic pivotal joints pivotally supporting each rocker member and being insulated from each other, a pair of xed terminals for each rocker member, and means forming separate connections from the contacts on each rocker member through said joints to the respective fixed terminals.

3. A contact assembly according to claim 1 wherein said rocker member is formed of insulating material.

4. A switch according to claim 2 wherein said rocker members are formed of insulating material.

RUPERT EVAN HOWARD CARPENTER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Kight Jan. 25, 1944

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