US2734179A - Connection block for an electro- - Google Patents

Description

Feb. 7, 1956 2,734,179

R. S. LEVEN SON CONNECTION BLOCK FOR AN ELECTROMAGNETIC POLOR RELAY Filed Feb. 24, 1953 y INVENTOR ROBERT 6. fyfNso/v BWM v ATTORNEY United States "i atent CONNECTION BLGCK FR AN ELECTRG- MAGNETIC PLAR RELAY Robert S. Levenson, New York, N. Y., assignor, by mesne assignments, to Metropolitan Telephone Supply Corp., Brooklyn, N. Y., a corporation of New York Application February 24, 1953, Serial No. 338,532

2 Claims. (Cl. 339217) The present invention relates to polar relays used in high speed polar telegraph and allied circuits, and, more particularly, to connection block structure for polar relays and the method of making same. Such relays are designed to operate on current reversals of the order of 30 milliamperes. Operation at this current level plus the fact that telegraph and allied equipment are involved make good electrical connections in the relay circuit indispensable. Consequently, the relay is subjected to surveillance, repair and systematic cleaning by maintenance personnel to assure uninterrupted operation of the relay circuit.

One troublesome feature of the prior art relay structure revolves about the elort required to maintain good electrical connections at the base of the relay. The

relay terminal board, i. e., the connection block, of the prior art structure is made of laminated slabs of dielectric material. The electrical contact terminals embedded in the block are long, llat spring lingers. Electrical contact with the relay components is brought about by sliding a pin terminal along the llat surface of the spring finger. The electiveness of this type of electrical connection depends solely upon the quality of the sliding contact between the surfaces of a cylindrical body (the pin terminal) against a flat body (the spring finger). Operation of the whole relay circuit is hampered or prevented, if for any reason there is a poor electrical connection along this single line of contact.

Furthermore, the laminated block design of the prior art structure has the tendency of collecting dirt and grit. It therefore is necessary to clean and service such relays wherever they may be to avoid arcing and voltage breakdowns. When the relay is inaccessibly located, extensive precautions must be observed to minimize arcing because of grit accumulations in the laminated block. The laminated block structure also limits the voltage load safely carried by the relay. ln addition, the laminated structure is relatively expensive to manufacture.

rlhe present invention is directed to overcoming the drawbacks associated with the prior art relay design. A polar relay and, more particularly, a connection block therefor built in accordance with the present invention assures good electrical connections at the rela;l base. The invention calls for a relay base and a relay connection block each made of a unitary slab of high dielectric material. Each contact terminal embedded in the connection block is furnished with three spring lingers oriented to provide a three-sided electrical contact with the engaging pin terminal. A three-sided electrical contact oers the advantages of multi-contacts. Hence, a defect in one contact will not adversely affect the electricalconnection of the circuit. A

Furthermore, the relay connection block built pursuant to the present invention is adaptable to mass production manufacture by unskilled labor. This latter feature is attributed to the simple design afforded by the unitary slab and to the locking arrangement employed to hold the contact terminal in the block. Moreover, dirt rice accumulation is reduced, and as a result arcing is prevented. The present invention also provides a construction of increased ruggedness; consequently, the relay can withstand greater shock loads. Further advantages are realized by the present invention; such as: the voltage load of the relay is increased, the cost of manufacture and maintenance costs are decreased. ln addition, the locking technique employed to hold the contact terminal in the block permits removal of the terminal for repair without requiring the disassembly of the block.

It is, therefore, an object of this invention to improve the electrical connections in a polar relay circuit whereby good electrical .connections are maintained for relatively long periods without the need of frequent or periodic maintenance of the relay circuit.

A further object is to provide a three-sided electrical contact between the pin terminals and spring finger terminals in a polar relay circuit.

A further object is to provide a polar relay connection block adaptable to mass production manufacture by unskilled labor whereby the costs thereof are reduced substantially.

A further object is to provide a polar relay structure less susceptible to collecting foreign matter whereby arcing and voltage breakdowns are minimized.

A further object is to provide a method of fabricating a polar relay connection block of a single slab of dielectric material.

A further object is to provide a relay structure having improved mechanical and electrical ruggedness.

Further objects and advantages of the present invention will become apparent from the following specilication and figures in which,

Fig. l is a composite view, partly in section, illustrating a polar relay embodying the features of the present invention;

Fig. 2 is taken along line 2--2 of Fig. l;

Fig. 3 is taken along line 3-3 of Fig. 1;

Fig. 4 is a perspective view of a spring nger terminal;

Fig. 5 is a sectional view of a spring nger terminal embedded in a connection block;

Fig. 6 is a longitudinal View, partly in section, of a crinkling jig; and

Fig. 7 is another view'ot the crinkling jig.

Referring to the figures, polar relay 9 employs an U- shaped permanent magnet 1l) having poles 11, 12. A return pole piece 13 of magnetic material has parallel extending arms 14, l5 interposed poles 11, 12. Adjustable pole screws 16, 17 are threadedly engaged to and carried by arms i4, 1S respectively. Pole screws 16, 17 extend in alignment laterally from respective supporting arms 14, 15 and form a working air-gap 18 between their adjacent ends. An armature 19 is supported at one end 2@ by return pole piece 13. Armature y19 extends through gap 1S and terminates at a free end 21. A pair of electrical insulators 22, 22 electrically isolate armature 19 from return pole piece 13 at supporting end Ztl. A pair of electrical contacts 7, S straddle armature i9 close to its free end 21. Contacts points 70, 71,: 72 and 73 are of sulllcient length to prevent an electrical short of the armature 19 with either pole screw 16, 17 upon an electrical closed circuit of armature 19 with either contact point 70, 73. A pair of accurately balanced current conducting windings 23, 24 surrounds armature 19. Axial hole 2S of windings 23, 24 is large enough to permit free lateral vibration of armature 19 therein. A multi-terminal base 26 carries a plurality of pin terminals 32 to which electrical connections are made with armature 19, contacts 7, 8, and windings 23, 24.

The magnetic paths of the polarizing flux are illustrated by solid lines 27, 28, 28. Assuming that windings 23, 24 are connected to create additive magnetic ux, the magnetic paths of such flux are shown by dashed lines 21?, 3i). The magnetic influence of the current in windings 23, 24 on armature i9 depends on the current directions in the windings 23, 24. When the current passes through the relay windings, the operating flux set up bythe windings adds to the polarized flux in one part of air gap 13 and subtracts from the polarized flux in the other part ot' air Igap llS. Armature i9 moves laterally into the portion of gap 1S of greater iiux density until electrical contnc is made by one pair of electrical Contact points 70, 7 ,f 72, '73. When the current is reversed, armature i9 is attracted toward the opposite direction.

Relay base 26 is made of a unitary slab 3i of high dielectric material to which a plurality of pin terminals 32 are embedded. Each terminal 32 is threadedly embedded toslab -31 by means of a nut 33 engaging the threaded `portion 34 of pin terminal 32, washers 3S, 36 and shoulder 37.

, Connection block. 38 has a unitary slab 39 of high dielectric material of suitable thickness T. Two rows 4i, 42

of aligned, cylindrically shaped recesses 43 extend inwardly from front engaging surface 44 and terminate at Arear or bottom inner wall 45. Recesses 43 are arranged .along two l'aligned rows 41, 42 to facilitate manufacture of connection block 33. hereinafter.

Ajright-angled slot 46 extends along rear surface 47. Slot 46 is in alignment with the common center line of row 41. The width W of slot 46 is substantially less than the diameter ofrecesses 43. Slot 46 extends in depth beyond inner wall 45. As a result a row of continuous openings exists between surfaces 44, 47. Each opening is the combination of a recess 43 and a constricted portion formed by slot 46. The constriction starts at inner wall 45.

A second slot 49 is provided in a similar relationship with respect to row 42 of recesses 43.

Mounting brackets 5o are fixed to slab 3) by means of bolts 51 engaging threaded holes 69.

A spring finger terminal 53 of thin electrical conducting material is spring-locked in each recess 43. Terminal 53 -has'an engagingfront end of center finger 5d and astriding sidengers 55, 56. Rear edges 57 of side fingers 5S, S6 are pressed against rear inner wall 45, note Fig. 5. Center linger 54 extends into and through the constricted portion of the opening and continues beyond rear surface 47. A rear portion 52 of center finger 54 is contiguous to wall 5;? of the correlated slot and contiguous to rear surface 47. A hole 6) is provided at the rear to which an elecvtricalconnection Vcould be made. out 62 predeterminedly located to be at corner d when the terminal is embedded in its correlated recess 43. Cutoutj62 facilitates crinkling terminal 53 during the manufacture of the connection block 38. Cutout 6.?. also improves the holding or locking characteristic of the crinkle, because cut-out edge 68 presses against surface 47. The crinlsle'in conjunction with the holding o stop characteristicproduced by edges 57 pressing against rear wall 45 spring-locks terminal S3 in its correlated recess 43.

The three spring fingers 54, 55, 56 lie in planes oriented to form a three-sided electrical contact terminal. Each finger presents a separate contacting surface upon engagement with pin terminal 32.

p Terminal 53 `can be removed very easily from its correlated recess 43`to permit repair or replacement without the need of disassembling the connection block 33 or disturbing the other electrical connections of the relay cir cuit. .By wiggling exposed rear end 61 until the locking action of the crinltle is destroyed, terminal 53 may be withdrawn from its correlated recess 43.

In thefmanufacture of connection block 3S, it is preferable to start with a long stock of solid dielectric material of suitable thick-ness and width. The stock is cnr by conventional means to desired length L. The cut slab 39 is'placed into. a conventional drill jig. Two parallel This feature will be illustrated Terminal 53 has la cutiii) extending rows 41, 42 of valigned Vholes 43 are 'drilled into slab '39 a suitable depth from front surface 44. In one embodiment, eight holes each 5716 were drilled Sys deep into a slab 1%6 thick. The holes are then countersunk 63. Slab 39 is turned over and holes 69 are drilled a suitable depth from rear surface 47 after which said holes are threaded for the purpose of attaching brackets 50 to slab 39 by means of bolts 51. Two parallel extending right- angled slots 46, 49, each in alignment with the common center line of a correlated row 41, 42 of holes 43, are cut along rear surface 47. Slots 46, 49 are cut by conventional means, i. e., milling machine. The width of slot- s 46, 49 are substantially less than the diameter of holes 43. In the same embodiment "referred to above, the width of slots 46, 49 was 374,2. The depth of slots 46, 4? should be greater than the undrilled dimension of the slab, i. e., the distance between rear bottom wall 45 and rear surface 47.

Thus each hole 43 and its correlated slot form an opening extending through slab 39 between front and rear surfaces 44, 47.

A prefabricated contact terminal 53 is inserted intoV each hole 43. Terminal 53 may be made by a conventional punch press process, Which process is not shown here because it is not deemed to be part of the instant invention. Exposed ends 6I. are Vextracted from slots 46, 4h until edges 57 press against the bottom -surfaces or rear inner wall 45 Vof the correlated hole 43. The rear portion of center linger 54 of terminal 53 is thereby iiexed slightly andas a result creates sufficient llateral pressure against the adjacent wall lof the correlated slot to hold terminal 53 in place until it is permanently locked in its correlated hole 43.

Connection block 3S is then insertedrin a crinkling jig '64 `with rear surface 47facing upward. Jig 64 consists of a pair of laterally moving press bodies 67, a solid rightangled anvil 65 hinged at 74 and a seat into which connection block 33 is held during the crinkling of ends 61. The seat is Yformed by sides 76, 77 and bottom 7S. The seat is arranged to hold block 38 so that anvil 65, when lswung to position 75 to rest upon. surface 47, extends between the two rows of exposed ends 61.

Anvil 65 is swung-into position 75. The anvil width 66 is slightly less than the distance between adjacent walls 59 of slots 46, 49. Press bodies 67 are brought together in the direction of arrows 79 to bear pressure against exposed ends 61, which ends are thus pressed lagainst adjacent walls 59, rear surface 47 and adjacent walls of anvil '65 and thereby deformed. Bevels 80 prevent press bodies from shearing ends 61. The ends 6l hold their deformed shape upon withdrawal of press bodies67 and removal of block 38 from jig 64. Cutout 62 is suitably located along center fiuger54`so that its upper edge 6B appears slightly above rear surface 47 before crinkling. Deformation or crinkling of center finger 54 is Y-made easier by the presence of cutout 62. Furthermore, lupper edge 6d, after deformation, rests upon rear surface 47 and thereby contributes to the locking action provided by the crinlile.

It is Vintended that all matter set forth in the above description and shown in the accompanying figures shall be interpretedas illustrative and not in a limiting sense.

What is claimed is:

1. A connection block for an electromagnetic polar relay device comprisinT a one piece block of dielectric material having front and rear surfaces separated 'by a predetermined thickness, said bloc-l; having two straight rows of cylindrically shaped and aligned openings extend ing inwardly from said front surface to an inner bottom wall, `said block having a pair of right-angled slots of predetermined width lessthanfthe diameter of said openings, each of said slots being aligned with the common center line of a correlated Arow of openings, said slots extending into-said bloeit-from said 'rear surface -a distan'cegreater than the r-distan'ceof said'inner bottomwall .hat

to said rear surface, and a three-lingered contact for each of said openings, said contact having a center linger and a pair of astriding side fingers within the correlated opening with each linger lying in a plane making an angle less than ninety degrees with respect to the plane of the adjacent inger, whereby a three-sided sliding electrical connection is achieved upon mating of said lingers with a pin terminal, said side lingers having rear edges pressed against said inner bottom wall of a correlated opening, said center linger extending past said inner wall and through a correlated slot and having portions thereof contiguous with a wall of said slot and with said rear surface, said center finger having a cutout at the contiguous portions thereof, an edge of said cutout being juxtaposed to and pressed against said rear surface whereby said contact is locked in position.

2. A connector block for electing electrical connections with a plurality of rod-shaped terminals comprising, a one-piece body of insulating material, and a plurality of electrical conducting contacts embedded in said body, said body having front end and rear end surfaces and a plurality of end-to-end passages each being adapted to receive a contact, said passages consisting of a plurality of aligned rows of cylindrical-shaped openings extending inwardly from said front end and terminating at a bottom wall intermediate said surfaces, and a plurality of right-angled grooves of Width less than the diameter of said openings, each groove being aligned with the common center line of a correlated row of openings, said grooves extending inwardly into said body from said rear end surface a distance greater than the distance between said bottom wall and said rear end surface, said contacts each consisting of a thin ilat length of resilient' conducting material having a terminating end, a center linger extending forwardly from said terminating end within the cylindrical opening of its correlated passage and a pair of side fingers substantially integral with and straddling said center iinger, said side fingers being folded along the edges thereof common with said center linger at an acute angle whereby said lingers form a three-sided disengageable receptacle for effecting an electrical connection with a rod-shaped terminal, said side ingers having rear edges extending transversely to the lengthwise dimension of said contact and abutting said bottom wall of a correlated opening, said contact terminating end protruding rearwardly beyond said bottom wall and through a correlated groove, said terminating end being bent over and having a recessed edge forming a cut-out predeterminedly located to engage said rear end surface whereby each contact is locked in a correlated passage.

References Cited in the tile of this patent UNITED STATES PATENTS 2,053,102 Palmer Sept. 1, 1936 2,082,493 Hartman June l, 1937 2,211,726 Knutson Aug. 13, 1940 2,318,912 Alden May 11, 1943 2,377,265 Rady May 29, 1945 2,525,210 Del Camp Oct. l0, 1950 2,529,502 Kelly Nov. 14, 1950 2,533,933 Heath Dec. 12, 1950 2,575,161 Deakin Nov. 13, 1951

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