US3171918A

US3171918A - Encapsulated reed relay

Info

Publication number: US3171918A
Application number: US194131A
Authority: US
Inventors: William A Killion
Original assignee: Essex Wire Corp
Current assignee: Essex Wire Corp
Priority date: 1962-05-11
Filing date: 1962-05-11
Publication date: 1965-03-02
Anticipated expiration: 1982-03-02

Description

March 2, 1965 w. A. KILLION 3,171,918

ENCAPSULATED REED RELAY Filed May 11. 1962 I INVENTOR 2| 22 23 WILLIAM A. Kl LLION BY Fl 6- 2 MD 13W AGENT United States Patent 3,171,918 ENQAPSULATED REED RELAY William A. Kiilion, Logansport, Ind, assignor to Essex Wire Corporation, Fort Wayne, Ind, a corporation of Michigan Filed May 11, 1962, Ser. No. 194,131 3 Claims. (Cl. mil-87) This invention relates to electrical switches and, more particularly, to magnetically operated switches of the sealed reed type.

Miniature reed switches relays of the type to which this invention relates comprise basically one or more sealed switch units associated with an electromagnetic coil. Frequently, it is desired to mold or encapsulate the components of the relay in a block of resin plastic material for the purpose of protecting the relay against the effects of humidity, shock and other adverse conditions. 'Two arrangements have been generally adopted for providing electrical connections to the encapsulated relay. In one arrangement, flexible wire leads extend from two or more sides of the relay. In the other arrangement, the relay is connected to rigid terminals of a terminal board mounted at one end of a case or housing containing the relay and a filling of plastic resin. Various problems exist in the handling of relays constructed according to the first arrangement and in the attachment of the wire leads to printed circuit panels or other circuitry. Relays constructed according to the second arrangement are generally more expensive and difficult to manufacture and are more bulky.

Accordingly, it is the general object of this invention to provide an improved encapsulated reed switch relay.

More specifically, the object of this invention is to provide an encapsulated reed switch relay of minimum size and weight having a simplified structure which can be economically manufactured and in which the terminal leads of the relay components are precisely located for ready assembly with other circuit components and capable of providing mounting support for the relay.

According to this invention, one or more reed switches,

together with an associated electromagnetic coil, are

placed in a case of insulating material having an open top. The terminal leads of each reed switch and the coil are bent to extend at generally right angles to the axes of the switch and the coil. The ends of the terminal lead wires are seated in opposite pairs of grooves provided in the end walls of the case to accurately locate the terminal leads in relation to each other. A casting of insulating material completely fills the case to cover the reed switch and the coil. The ends of the terminal leads extend from the casting material at the top end of the case to provide external connections to the relay assembly and to provide mounting support for the relay assembly.

Other objects and features of the invention will be apparent from the following description taken in connection with the accompanying drawing, in which:

FIGURE 1 is an exploded isometric view of one form of the invention, showing the several parts of the reed switch relay in the order of their assembly;

FIGURE 2 is a top end view of the fully assembled and encapsulated relay of FIGURE 1;

FIGURE 3 is a longitudinal sectional view taken on the line 33 of FIGURE 2;

FIGURE 4 is an isometric view of another form of the invention similar to the first form and embodying the same principles; and

FIGURE 5 is an isometric view of a component of the relay of FIGURE 4, showing an assembly of three reed switches and a coil.

3,171,913 Patented Mar. 2, 1965 ice The particular embodiment of the invention shown in FIGURES 1-3 comprises a case 10 of suitable insulating materials such as a thermosetting phenolic plastic resin, an electromagnetic coil 11 which includes a bobbin 12 and a winding 13, a reed switch 14 which fits within the bobbin 12 and projects therefrom, a pair of

magnetic shunts

15 and 16 positioned on oppotite sides of the coil 11, and a casting 17 or" an insulating material such as an epoxy resin which fills the case 10.

The case 10 is a generally rectangular hollow member having parallel, spaced sides 18, parallel vertical sides 19 and a bottom 20 closing the lower end of the case 10. From each of the sides 18, integral spaced

lugs

21, 22 and 23 extend upwardly at the outer edge of each side 18 as shown. At the inner face of each end 19, three shallow grooves or recesses 24 extend vertically from near the bottom 20 to the outer edge portion of each 'end 19 at the open top of the case 10.

The reed switch 14 is of a well known construction comprising two reeds or contact members 25 and 26 mounted in the ends of a hermetically sealed tubular envelope 27 of glass with overlapping ends or contact areas which are free to move toward and away from each other. The reeds are made of suitable magnetic material such as a nickel-iron alloy so that in the presence of a magnetic field they will be attracted together. The overlapped contact areas of the reeds 25, 26 may be plated with gold or other suitable contact material. The external ends or terminal leads 28 of the reeds 25, 26 are preferably in the form of round wires. The ends 28 project from the ends of the envelope 27 in the general direction of an envelope axis. At a short distance from the envelope 27, the ends 28 are bent at right angles, as indicated at 29, to extend radially in the same direction from the reed switch. The spacing between the reed ends 28 is substantially equal to that of the oppositely facing grooves '24 in the case ends 19 so that the reed ends 28 may be seated in a pair of the grooves 24.

The bobbin 12 is preferably molded as an integral unit of suitable non-magnetic and insulating material such as nylon and includes a hollow cylindrical core or barrel 30 which terminates in a pair of flanges or bobbin heads 31. The interior of the barrel 30 is dimensioned to receive the envelope 27 of the reed switch 14 with a snug fit. The initial and final turns of the winding 13 are connected to oppositely disposed terminal leads 32 of tinned copper wire. These terminal leads 32 are each formed with a short portion 33 extending outwardly from the edge of a bobbin flange 31 in the general direction of the axis of the bobbin 12. The end portion 34 of each terminal lead 32 is bent at right angles to the portion 33 such that the portions 34 are parallel to each other. The end portions 34 have a spacing substantially equal to that of the oppositely facing grooves 24 in the casing ends 19. In addition, each end portion 34 is parallel with the adjacent reed end 28 and is spaced therefrom a distance substantially equal to that between adjacent grooves 24 in either case end 19. When the coil and switch assembly shown in FIGURE 1 is inserted in the case 10, the reed ends 28 are received in the center grooves 24 and the terminal lead end portions 34 are received in the adjacent outer pair of grooves 24. Thus, the free ends of the coil terminal leads 32 and of the reeds 25, 26 extend from the open top of the case 10 in a predetermined relation to each other.

The

magnetic shunts

15 and 16 are formed of a magnetic sheet metal such as a nickel-iron alloy to provide low reluctance paths for the flux developed by the coil 11. The lower shunt 15 comprises a plane body or base portion 35 and two legs 36 of reduced width formed at right angles thereto on either side. Each leg 36 is provided switches. "to'provide' an electrostatic shield between the reed switches 114 and thecoil111 by means of a thin strip of electrispaced apart somewhat less than the distance between the case ends 19. Thus, when the base portionSS is laid upon the case bottom 20, the shunt 15 assumes'a predetermined "position in'the case 10. The legs36 are separated by a distance slightly more than the length of the bobbin 12 and cooperate with the coil terminal leads 32 in position- 'ing the bobbin 1'2 axiallywithin the case 111. The length of each leg 36 is sufficiently less than the radius of the bobbin flanges 31 so that the feet 37 of the shunt 15 are slightly spaced from the ends 27 of the reeds 25, 26. The upper magnetic shunt 16 similarly has a base portion 38 of the same dimensions as 'the base portion 35 and rests upon the'upper edges of the bobbin flanges 31. The base portion 38 also has two legs 39 of reduced width formed at right angles thereto on either side which snugly fit over the-sides of the bobbin flanges 31 with their ends slightly spaced from the ends 28" of the reeds 25, 26.

After the coil 11, the reed switch 14 and the

magnetic shunts

15 and 16 have been placed in the case 10, an insulatingresin material such as the usual encapsulating type epoxy resin is poured while in its liquid state into the case until the case is filled. The casting 17of this insulating materialcompletely fills the space between the coil 11, the switch 14, the shunts and 16, and the case It to bond these parts together in a unitary assembly. The ends 28 of the reeds 25, 26 and the endportions 34 of the coil terminal leads 32 extend from the casting 17 to provide external connections to the coil 11 and the reed switch 14. When so encapsulated, the parts of the relay are completely enclosed and embedded in the casting 17 and thoroughly protected against the effects of humidity and other adverse conditions.

It will be apparent that the exposed ends or terminal leads of the reeds 25, 26 and the coil terminal leads 32 are precisely located with respect to each other and can be easily assembled to a printed circuitpanel or an electrical connector. Because of the minimum weight of the relay associated with the construction described, terminal leads of the order of 0.025 inch diameter have sufficient mechanical strength in relation to the weight of the assembled relay to provide the entire mounting support for the relay.

The lugs Z1, 22 and 23 of the case 10 serve to space the relay assembly from a panel to which it may be connected and thus prevent the accumulation of moisture or other contaminants between the relay assembly and the panel. By use of such lugs in mounting the relay on a panel-orthe like, it is not necessary to machine off the usually-uneven and rough surface of the casting to provide a flat-mounting surface.

In the arrangementof FEGURES 4 and 5, there is illustrated essentially the same construction as described for FIGURES 1-3 but'in application to a relay having three reed switches 114 operated by a single coil 111. The case 10 may be the same asdescribed for the first embodiment exceptthat it'is, of course, wider and is provided with additional grooves or slots similar to the grooves 24 for receiving the coil terminal-leads 132 and the reed ends or terminal leads 128 of the switches 114. Instead devices from the magnetic field of the coil 111 or of any permanent magnets which may be associated with the reed For certain applications, it may be desirable caliy conductive material wound about the reed switches 4 r 114. After the assembly of the coil 111 and the reed switches 114 is placed in the case 110, the case 114 is filled with a casting 117 of suitable insulating plastic resin material.

It will be seen that this invention provides an improved construction of an encapsulated reed switch relay that uses relatively few and inexpensive component parts and that may be encapsulated by a simple casting operation requiring no molds other than the case itself. The -encapsulated relay maybe easily secured to a printed circuit panel by solderingof the extended portions of the coil terminal leads and the reeds of the reed switches and there .is no need for any other mounting means to be provided.

ponents of the relay.

While particular embodiments of the invention have been shown and described, modifications thereof may be made, and it is intended in the appended claims to cover all such modifications as fall Within the scope of the inventionas claimed.

What is claimed is:

1. An encapsulated relay assembly comprising:

(a) A sealed reed switch having a terminal wire lead at each end thereof and projecting therefrom in the general direction of the switch axis;

(1)) An electromagnetic coil associated with said switch, said coil having oppositely disposed'terminal wire leads projecting therefrom in the general direc tion of the coil axis;

(c) A case of insulating material containing said switch and coil, said case having end walls and an open top, the inner faces of said end walls being formed with two pairs of-oppositely facing, parallel grooves extending to said open top;

(d) The free ends of said switch and coil terminal leads being bent at right angles and; extending generally parallel to each other, each of said free ends of the terminal leads having a portion seating in a separate one of said grooves for locating said -free ends in predetermined relation to each other;

(e) A casting of insulating material within said case filling the space between said switch, coil and case and completely covering said switch and coil; and

(f) Said terminal leads extending outwardly from'said casting through the open top of said case in substantially the same direction and having the exposed ends thereof parallel and spaced in predetermined relation.

2. An encapsulated relay assembly comprising:

(a) A scaled reed switch comprising a tubularenvelope and two terminal wire leads extending from-respective ends of said envelope in the general direction of the envelope axis;

(b) An electromagnetic coil encompassing said envelope, said coil having oppositely disposed terminal wire leads-projecting therefrom in the generaldired tion of the axis of said envelope;

(0) A hollow, generally rectangular case of insulating material having an open top and bottom, side and end walls, the inner faces of said end Walls being formed With pairs of oppositely facing, parallel groovesextending to said open top;

(d) Said .switchand coil being'dispo'sed in said case with said terminal leads extending toward said end walls, thefree endsof said terminal leads being bent at right angles .and'extending generally parallel to each other in substantially the same direction, each of said free ends of the terminal leads having a portion seating in a separate'one'of'sai'd grooves for locating said free ends in predetermined relation to each other;

(f) Said terminal leads extending outwardly from said casting through the open top of said case to provide external connections to said switch and coil.

3. An encapsulated relay assembly according to claim 2 wherein the mechanical strength of said terminal leads in relation to the weight of said assembly is such that said outwardly extending terminal leads provide mounting support for said assembly.

4. An encapsulated relay assembly according to claim 3 wherein said case is provided with a plurality of spaced lugs extending from each of said side walls in the same general direction as said outwardly extending terminal leads, said lugs having a height less than the length of the exposed portions of said outwardly extending terminal leads.

5. An encapsulated relay assembly comprising:

(a) A bobbin of non-magnetic material comprising a hollow barrel and a pair of spaced apart end flanges attached to barrel;

(b) An energizing coil of wire wound around said barrel between said flanges, said coil having oppositely disposed terminal wire leads projecting therefrom in the general direction of the axis of said barrel;

(c) A sealed reed switch mounted within said bobbin barrel, said reed switch having a terminal Wire lead at each end thereof and projecting therefrom in the general direction of the axis of said barrel;

(d) A hollow generally rectangular case of insulating material having an open top and bottom, side and end walls, the inner faces of said end walls being formed with a plurality of pairs of oppositely facing, parallel grooves extending to said open top;

(e) Said switch and coil being disposed in said case with said terminal leads extending toward said end walls, the free ends of said terminal leads being bent at right angles and extending generally parallel to each other in substantially the same direction, each of said free ends of the terminl leads having a portion seating in a separate one of said grooves for locating said free ends in predetermined relation to each other;

(f) A casting of insulating material within said case filling the space between said bobbin, coil, switch and case and completely covering said bobbin, coil and switch; and

(g) Said terminal leads extending outwardly from said casting through the open top of said case in parallel and predetermined spaced relation to provide external connections to said switch and coil.

6. An encapsulated relay assembly according to claim 5 including at least one additional sealed reed switch mounted within said bobbin barrel, each such additional switch having a terminal lead at each end thereof and projecting therefrom in the general direction of the axis of said bobbin barrel, the free ends of the terminal leads of each such additional switch being bent at right angles and seating in a pair of said oppositely facing grooves of said case, said terminal leads of each said additional switch extending outwardly from said casting through the open top of said case.

7. An encapsulated relay assembly according to claim 5 including a pair of magnetic shunts positioned on opposite sides of said bobbin, each of said shunts having end portions in closely spaced relation to said terminal leads, and said casting completely covering said shunts and bonding the latter together with said bobbin, coil, switch and case in a unitary assembly.

8. An encapsulated relay assembly according to claim 5 including a strip of flexible magnetic material wound around said coil between said bobbin flanges, and said casting completely covering said magnetic material and bonding the latter together with said bobbin, coil, switch and case in a unitary assembly.

References Cited by the Examiner UNITED STATES PATENTS 2,549,323 4/51 McMullen et al 20087 2,630,506 3/53 Buch 200-87 2,810,039 10/57 Every 200-93 2,845,585 7/58 Vincenzi et al. 200-87 2,870,287 1/59 Corbitt et al 20087 2,889,423 6/59 Yochum ZOO--87 3,056,868 10/62 Jacobson et al 20087 BERNARD A. GILHEANY, Primary Examiner.

R. K, SCHAEFER, Examiner.

Claims

1. AN ENCAPSULATED RELAY ASSEMBLY COMPRISING: (A) A SEALED REED SWITCH HAVING A TERMINAL WIRE LEAD AT EACH END THEREOF AND PROJECTING THEREFROM IN THE GENERAL DIRECTION OF THE SWITCH AXIS; (B) AN ELECTROMAGNETIC COIL ASSOCIATED WITH SAID SWITCH, SAID COIL HAVING OPPOSITELY DISPOSED TERMINAL WIRE LEADS PROJECTING THEREFROM IN THE GENERAL DIRECTION OF THE COIL AXIS; (C) A CASE OF INSULATING MATERIAL CONTAINING SAID SWITCH AND COIL, SAID CASE HAVING END WALLS AND AN OPEN TOP, THE INNER FACES OF SAID END WALLS BEING FORMED WITH TWO PAIRS OF OPPOSITELY FACING, PARALLEL GROOVES EXTENDING TO SAID OPEN TOP; (D) THE FREE ENDS OF SAID SWITCH AND COIL TERMINAL LEADS BEING BENT AT RIGHT ANGLES AND EXTENDING GENERALLY PARALLEL TO EACH OTHER, EACH OF SAID FREE ENDS OF THE TERMINAL LEADS HAVING A PORTION SEATING IN A SEPARATE ONE OF SAID GROOVES FOR LOCATING SAID FREE ENDS IN PREDETERMINED RELATION TO EACH OTHER; (E) A CASTING OF INSULATING MATERIAL WITHIN SAID CASE FILLING THE SPACE BETWEEN SAID SWITCH, COIL AND CASE AND COMPLETELY COVERING SAID SWITCH AND COIL; AND (F) SAID TERMINAL LEADS EXTENDING OUTWARDLY FROM SAID CASTING THROUGH THE OPEN TOP OF SAID CASE IN SUBSTANTIALLY THE SAME DIRECTION AND HAVING THE EXPOSED ENDS THEREOF PARALLEL AND SPACED IN PREDETERMINED RELATION.