US3420973A - Adjustment-free preassembled contact unit for multiple contact relays which may be completely prefabricated by mechanical operations - Google Patents

Description

Jan. 7, 1969 J. FISCHER ET AL 3,420,973

ADJUSTMENT-FREE PREASSEMBLED CONTACT UNIT FOR MULTIPLE CONTACT RELAYS WHICH MAY BE COMPLETELY PREFABRICATED BY MECHANICAL OPERATIONS Filed April 20, 1967 I Sheet of 2- INVENTORS Jase; Fx scx-lsg #52552 KQ407'W440 #5 07 50/5054: evdfipd ATTORNEYS Jan. 7, 1969 J. FISCHER ET AL ADJUSTMENT-FREE PREASSEMBLED CONTACT UNIT FOR MULTIPLE CONTACT RELAYS WHICH MAY BE COMPLETELY PREFABRICATED BY MECHANICAL OPERATIONS Filed April 20. 1967 Sheet .2 of2 INVENTORS ATTORNEYS United States Patent s 103,404 U.S. Cl. 200-166 7 Claims Int. Cl. H01h 1/36; H01h 1/12,- H01h 9/02 ABSTRACT OF THE DISCLOSURE An adjustment-free preassembled contact unit for multiple contact relays, in which a contact unit is positively supported in a tensioned U-shaped carrier rail, the contact unit comprising a preassembled structure having a central movable contact spring and spring supports for the cooperating contact springs, together with the connecting lugs therefor which are produced from a common metal strip, and i.e. in a common plane, said element being embedded in a plate-like body of insulating material, the cooperating contact springs attached to said spring carriers extending at right angles with respect thereto, and extending in prestressed relation in recesses formed in the plate-like body.

The disclosure The invention relates to a contact unit for multiple contact relays which will enable a mechanized and adjustment-free assembly thereof. In conventional production methods it is, as a rule, necessary in relay contact spring assemblies to combine the separate parts of each contact structure into a unit by a costly stacking operation. Subsequently, it is still necessary in most cases to adjust the contact springs in order to obtain predetermined performance values. However, the stacking and adjusting operations consume considerable time so that a compete mechanical production is not feasible.

It is the objective of the present invention to produce a contact unit of the kind described, which can be fabricated completely mechanically and in which no subsequent adjustment is required. According to the invention, this can be accomplished by a contact unit insertable as a carrier into and positively positioned within a tensioned U-shaped rail, such unit representing an individual part of the apparatus (preferably constructed as a switching contact) and supporting the spring carriers for the cooperating contact springs, the movable central contact spring, and the connecting terminal lugs therefor, which can be fabricated from a common metal strip, disposed in a common plane and embedded in a plate-like body of insulating material. In order to obtain close tolerance with respect to contact distances, the. cooperating contact springs, which extend at right angles to and fastened, preferably through spot welding, on the spring carriers, extend in prestressed condition into recesses in the plate of insulating material, forming fixed abutments.

Due to the fact that the contact parts, produced from a common metal strip, lie in the same plane, a mechanized production can be realized by a conveyor system, in various cycles of operation with the aid of molding tools, etc., without the possibility of the occurrence of positional tolerances. Moreover, a subsequent adjustment of the contact springs is eliminated through the field abutments on the plate of insulating material, since the contact distance is thereby automatically determined. To

3,420,973 Patented Jan. 7, 1969 ice prevent additional positional tolerances in the assembly of the construction unit which carries the contact structure, such construction unit is positively inserted in a tensioned U-shaped rail which forms the carrier therefor.

An advantageous further development of the invention provides that the movable contact springs of the respective contact units inserted in the U-shaped rail are actuatable by a common web-shaped slide bar. Since the webs of the slide bar can be produced with close tolerances, here, too, no critical tolerances are developed. For the sake of expediency the connecting lugs are provided in pairs for the respective contact springs forming the switch contact. The connecting lugs can be provided with stamped longitudinal reinforcement to increase their stability for the plug-like mounting. In addition, it can be advantageous to provide the slitted contact spring, which operates as a central spring, with double contacts at its deflectable end. In a suitable further development of the invention projections may be provided on the narrow side edges of the plate of insulating material for positive fastening in the tensioned U-shaped rail.

Further details of the invention will be apparent from the following description of an example embodying the same. In the drawing, wherein like reference characters indicate like or corresponding parts:

FIG. 1 is a perspective view of a contact according to the invention; and

FIGS. 2a to 20 are similar figures, on a reduced scale in relation to FIG. 1, illustrating the main parts of a multiple contact relay employing contact units in accordance with the invention.

FIG. 1 illustrates an adjustment-free, preassembled contact unit for a relay in accordance with the invention, capable of production by mechanized operations, utilizing a switching contact as a basis for explanation. In a plate-like body of insulating material, generally designated by the reference numeral 1, are embedded contact elements, produced from a common metal strip, comprising spring carriers 2a and 2b for the cooperable contact springs 3a and 3b, and in addition the movable central contact spring 2c which is slitted. From the lower end, as viewed in FIG. 1, of the body of insulating material project terminal lugs 2d and 2d provided with longitudinal stiffening depressions stamped therein. The contact elements, preferably embedded in the plate of insulating material in an injection operation lie in a single plane and can, therefore be simultaneously produced from a single metal strip.

In order to achieve small tolerances in the contact distances, the solid contact springs 3a and 3b, which are constructed with offsetting bends, are disposed at right angles with respect to the spring carriers 2a and 2b, and spot welded thereto, with such contact springs being pretensioned and extending into the recesses 1a and 1b of the body plate 1, which define positive positioning abutments therefor. Lateral projections 10 and 1d on the body plate I serve for the positive connection thereof Within a tensioned U-shaped sheet metal holder A, as illustrated in FIG. 2a, recesses a being provided therein for the reception of such projections.

The mechanized production methods possible with the contact arrangement in accordance with the invention can be such that a metal strip of spring material, whose thickness is primarily determined only by the movable central contact spring 20, is fed into a conveyor system. In corresponding compound tools such metal strip receives the necessary configuration through punching, free cutting and stamping, to form an insert for subsequent injection molding therearound with insulating material, in which operation the metal strip inserted in the form can at the same time effect the sealing of the injection mold. In following manufacturing processes the movable slitted central con- O tact spring 2c is provided with double contacts, out free and prestressed by bending it downward.

Subsequently, the cooperating contact springs 3a and 3b, which are still interconnected in a strip, can be welded on and separated. These cooperating contact springs can, by way of example, consist of a weldable spring material which carries a single layer of contact material. In the final steps of the process a separating punch or stamp separates the finished contact unit either by severance of the terminal lugs 20. or the terminal lugs 2d from the strip. A silver surface could be applied to both sides of the terminal lugs in a previous operation. By elimination corresponding cooperating contact springs, a working contact or a rest contact can be produced, in addition to a switching contact. In FIGS. 2a and 2c, the main parts of a relay are illustrated with the contact unit in accordance with the invention, in which a desired number of contact units corresponding to the individual part B, as well as the necessary electromagnetic system corresponding to the individual part C can be inserted in apertures a in the U-shaped rail A.

Since the apertures a are arranged in a precise division on the U-shaped rail A are preferably in a predetermined divisional pattern, no cumulative tolerances can occur. This is of great importance in relays which must be provided with a large number of contacts and in which, in the conventional production methods, a time consuming adjustment for the equalization of such cumulative tolerances is necessary. Likewise, as the webs of the slide bar D, illustrated in FIG. 2c, can be produced with close tolerances, no critical tolerances are involved, and the bar may be readily assembled with the armature 11 and the free end of the central contact spring 20.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim:

1. In an adjustment-free preassembled contact structure for multiple contact relays comprising the combination of a plurality of substantially flat plate-like units of insulating material formed with four edges and two sides, a U- shaped support formed with openings, said plurality of plate-like units received with said sides in parallel planes in said U-shaped support and with two of their opposite edges attached to the U-shaped support, a plurality of contact carrier supports with connecting lugs mounted in said plate-like units, a plurality of cooperating contact springs extending at right angles to said carrier supports and mounted thereon along one of the edges of said plate-like units, a moveable central contact spring embedded in each of the plate-like units of insulating material in a plane 0 parallel to said sides, said moveable central contact spring cooperable with the contact springs, and said plate-like units formed with recesses receiving prestressed ends of the contact springs to accurately position them, to form a unitary multiple contact structure.

2. A contact structure according to claim 1 comprising a common web-shaped slide bar slidably mounted on thr contact structure and engageable with said central con tact springs to actuate them.

3. A contact structure according to claim 1 wherein said connecting lugs are arranged in pairs for the contact carrier springs.

4. A contact structure according to claim 1 wherein the movable central contact springs are slitted.

2 5. A contact structure according to claim 4, wherein the movable central contact springs have double contacts on their free end.

6. A contact structure according to claim 1, wherein the connecting lugs possess longitudinal stamped depressions which increase their stability.

7. A contact structure according to claim 1 wherein said fiat plate-like units are formed with projections on their edges which are received within aligned openings formed in said U-shaped support.

ROBERT K. SCHAEFER, Primary Examiner.

HERMAN O. JONES, Assistant Examiner.

U.S. Cl. X.R.

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