US3211874A

US3211874A - Switch construction having improved contact and bracket assembly

Info

Publication number: US3211874A
Application number: US375993A
Authority: US
Inventors: Bertil S Bengtsson
Original assignee: Sigma Instruments Inc
Current assignee: Sigma Instruments Inc
Priority date: 1961-11-14
Filing date: 1964-05-12
Publication date: 1965-10-12
Anticipated expiration: 1982-10-12

Description

Oct. 12, 1965 BENGTSSQN 3,211,874

SWITCH CONSTRUCTION HAVING IMPROVED CONTACT AND BRACKET ASSEMBLY Original Filed Nov. 14. 1961 INVENTOR. BFRT/L S. BENGTSSON BY %w, 71- 1% a 702%) A T TORNE Y5.

United States Patent Claims. Cl. 200-166) This is a division of application Serial No. 152,261, filed Nov. 14, 1961.

This invention relates to electromagnetic devices and particularly to the construction of contact supporting brackets and contacts for relays suitable for general industrial use. Broadly stated, the objects of the invention are to provide a relay having long life, high switching capacity, high reliability, low manufacturing cost, and of such dimensions and characteristics as to be interchangeable with the largest number of competitive relays intended for use under comparable conditions.

A more specific and very important object of the present invention is to eliminate as far as possible the internal Wiring in the relay. Much of the available space inside the relay envelope has, in prior constructions, been occupied by wiring between the terminals of the relay proper and its base or plug-in termination. The wiring which has been heretofore required, aside from being space-consuming, is costly, and many solder points are required which are a constant source of trouble, possible breakdown and increased resistance. In the construction of the present invention most of the internal wiring and soldered joints are eliminated. It has thus been possible to utilize the available space in the relay envelope so that, without enlarging overall dimensions, it has been possible to lengthen the flexible members of the switches, thus permitting a larger cross section for a given spring characteristic. This has made possible reduction of the total contact resistance of the relay, terminal to terminal. This decrease in resistance is in addition to that secured by the elimination of many of the soldered joints required in previous constructions.

An important feature of construction which is preferably embodied in the structure of the present invention is the formation of various parts so as to include within the parts themselves fastening means by which the parts may be assembled. These formations cooperate with formations on other parts and particularly with spring clips by which the parts may be secured. The use of welding or soldering in joining parts is minimized and conventional fastening means such as screws, bolts or rivets are wholly or largely eliminated. Valuable space is thus saved, the expense and nuisance of handling many small parts is reduced, and the danger of screws and nuts becoming loosened during use is avoided.

Other objects and advantages of the invention will appear in the course of the following description of a preferred embodiment thereof. One such preferred embodiment is illustrated in the accompanying drawings. These drawings show a double pole double throw electromagnetic relay which may be provided in forms for either AC. or DC. operation. Many features of the invention are obviously applicable to other forms of relay and some of the features are useful in connection with other types of electromagnetic or switching apparatus. The applicability of the various inventive features disclosed is therefore not to be taken as limited to the particular type of relay illustrated.

FIG. 1 is a top plan view of the terminal pin base with the relay base assembled thereon and having contact ice brackets carrying their contact elements constructed in accordance with the invention;

FIG. 2 is a vertical section on line 2-2 of FIG. 1 showing the relay base mounted on the pin base;

FIG. 3 is a side elevation of the contact terminal bracket;

FIG. 4 is a fragmentary view in rear elevation of the upper part of the vertical arm of the contact terminal bracket shown in FIG. 3;

FIG. 5 is a side elevation of the relay shown in FIG. 1;

FIG. 6 is a side elevation of one of the spring contacts before being assembled; and

FIG. 7 is a front elevation of the same.

Referring to the drawings in detail, the illustrated embodiment of the invention is a double pole, double throw relay. The relay embodies a base 50 of insulating material carrying

terminal pins

52 and 52a arranged to fit in a conventional socket (not shown). Mounted on the base are a pair of normally open contacts 54 and normally closed contacts 56. These are engaged alternately by movable contacts 58 carried on contact springs 60. The contact springs are actuated by a pivoted armature 62 moved by an electro-magnet having a core 64 surrounded by a coil 66. When the coil is de-energized the armature is moved away from the pole face of the core by armature tensioning springs 68 so that the movable contacts 58 engage the normally closed contacts 56. When the coil is energized, the armature moves so as to relieve the pressure on the springs 60, which are prestressed so as to move the contacts 58 into engagement with the normally open contacts 54.

A novel construction of base is provided in which soldered connections are eliminated and also the use of screws and bolts.

The base is made in two pieces of insulating material such as thermo-setting phenolic plastic. The lower of these pieces, 70, comprises a pin base from which the

terminals

52 and 52a project, while the upper piece 72 may be termed the relay base. The pin base is shown as having a guide pin 71 molded integral therewith. On the pin base are mounted the brackets 74 carrying upwardly projecting arms 76 to which are fixed the movable contact springs 60. Also carried by the pin base are the brackets 78 carrying the normally closed contacts 56. The brackets 78 are separated from the brackets 74 by pieces of insulating material 82 (FIG. 2). Mounted on the relay base are brackets 84 carrying the normally open contacts 54. The pin base has a flange or shoulder portion 86 in which lugs 88 on the relay base fit. The pin base 70 and the relay base 72 and brackets 84 are all permanently clamped together by certain of the terminal pins 52, which are provided midway their length with flanges 90 fitting in sockets 92 in the bottom of the pin base and which have shank portions 94 extending through holes in the pin base 70 and up through matching holes in the relay base 72. The upper ends of the shanks are spun or flanged over as indicated at 96. The relay base is narrower than the pin base terminating at the line 98 (FIG. 1) so as to leave a space through which projects upwardly the spring-carrying bracket portions 76 and the contact-carrying portions 78 which carry the contacts 56. The brackets 78 are clamped against the insulating pieces 82 which, in turn, bear on the bracket 74, these parts being held in firm contact by pins 52a, the shanks 94a of which are shorter than the shanks 94 of pins 52.

The shanks of the terminal pins are of such diameter in relation to the sizes of the holes in the respective terminal brackets mounted thereon that the shanks have to be forced through the holes with substantial pressure. The force fit thus obtained insures good electrical contact without soldering. The shank diameter should be sufiiciently larger than the hole diameter to result in substantial stressing of the metal so that a tight contact is maintained under all temperature conditions to which the instrument will be subjected.

The contact springs 60 are of inverted U shape having legs 126 which are fixed to the arms 76 of the brackets 74. The arms 76 are shown as provided with holes 128 which receive outwardly bent lugs 130 on the lower ends of the spring legs 126. The arms 76 also have tongues 132 (FIGS. 3, 4) bent inwardly near their upper ends, and the spring legs 126 have tongues 134 (FIGS. 6, 7) bent outwardly so as to slide behind the tongues 132. The springs are thus held firmly by slipping the tongues 134 into position and the lugs 130 into the holes 128. The long outer legs 136 of the contact springs have fixed to their ends the movable contacts 58.

In devices of the lower ratings where current values are not too great, the mounting of the contact springs by means of the lugs and tongues described, forms a low resistance connection so that no other fastening means between the springs and the arms 76 of the brackets is required. This is advantageous because the assembly is very quickly effected without the use of any special tools and also the contact springs may be readily detached from the brackets for adjustment or replacement. Where high currents are involved, it may be desirable to weld or solder the springs to the brackets. In this case, the lug and tongue connections described facilitate the welding and soldering by holding the springs in proper position during such operations.

The base section comprising the pin base, relay base, pins carried thereby which also secure the base parts together, the fixed contact brackets and movable contact brackets and springs carried thereby, constitute a complete sub-assembly (FIG. 2) which may be put together by spinning over the ends of the pins as above described (and by welding the contact springs to their brackets, where this is needed).

While but one specific embodiment of this invention has been shown and described in detail, it will be understood that many variations may be made in the construction and that many features of the invention are capable of being used without others in different types of devices. It is desired, therefore, to cover the invention in whatever form its principles may be embodied.

I claim:

1. In an electro-magnetic switch construction, a contact supporting bracket and a U-shaped contact spring supported thereon, said bracket and spring having fiat portions arranged in juxtaposition and being provided with integral interlocking tongue formations on said flat portions for solely supporting and removably holding said spring in fixed position on the bracket.

2. A construction as claimed in claim 1 in which the interlocking tongue formations include inclined overlapping tongues bent from the bracket and spring respec tively.

3. A construction as claimed in claim 2, in which one of said bracket and spring members has a hole formed therein and the other of said members has a lug on said fiat portions at a spaced location from said tongue formations engaging said hole so as to prevent removal of the spring from the bracket without first disengaging said lug from said hole.

4. In a switch construction, a contact supporting bracket having a portion with a projecting bracket tongue extending obliquely outwardly therefrom and with an opening defined in said portion adjacent said tongue, a contact spring having a portion with a spring tongue extending obliquely outwardly therefrom in a direction opposite to said bracket tongue and engaged over said bracket tongue and into the opening defined in said bracket portion adjacent said bracket tongue, said contact spring being supported on said bracket solely by interengagement of said bracket tongue and said spring tongues.

5. In a switch construction, a contact supporting bracket having a portion with a projecting bracket tongue extending obliquely outwardly therefrom and with an opening defined in said portion adjacent said tongue, a contact spring having a portion with a spring tongue extending obliquely outwardly therefrom in a direction opposite to said bracket tongue and engaged over said bracket tongue and into the opening defined in said bracket portion adjacent said bracket tongue, said contact spring being supported on said bracket solely by interengagement of said bracket tongue and said spring tongues, said bracket having an-opening defined therein at a spaced location from said bracket tongue, said contact spring having a projection extending into the opening of said bracket for preventing removal of said contact spring from said bracket.

References Cited by the Examiner UNITED STATES PATENTS 2,769,881 11/56 Hailes 200166 2,967,216 1/61 Zablocki et al. 200166 X 3,076,063 1/63 Prace et al 200166 X 3,102,933 9/63 Berthier 200166 X BERNARD A. GILHEANY, Primary Examiner.

Claims

1. IN AN ELECTRO-MAGNETIC SWITCH CONSTRUCTION, A CONTACT SUPPORTING BRACKET AND A U-SHAPED CONTACT SPRING SUPPORTED THEREON, SAID BRACKET AND SPRING HAVING FLAT PORTIONS ARRANGED IN JUXTAPOSITION AND BEING PROVIDED WITH INTEGRAL INTERLOCKING TONGUE FORMATIONS ON SAID FLAT PORTIONS FOR SOLELY SUPPORTING AND REMOVABLY HOLDING SAID SPRING IN FIXED POSITION ON THE BRACKET.