US1727035A - Relay - Google Patents

Description

Sept. 3, 1929. F. H. PRESCOTT RELAY Filed April 1, 1924 Patented Sept. 3, 1929.

UNITED STATES PATENT OFFICE.

WARE.

BY MESNE ASSIGNMENTS, CORPORATION OF DELA- RELAY.

Application filed April 1,

This invention relates to magnetically 0perated circuit closers and more particularly to reverse circuit relays for battery charging apparatus.

It is among the objects of the invention to obtain the maximum pressure between the relay contacts for the minimum cost of construction. The objects include also such simplification of construction in relays of this type as will be conducive to the reduction of cost of manufacture and to ease in making adjustments.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of one form of the present invention are clearly shown.

In the drawings:

Fig. 1 is a plan view of a relay embodying the invention, the cover thereof being removed;

Fig. 2 is a sectional view substantially on the line 22 of Fig. 1, the cover being shown in section in this view;

Fig. 3 is a view in the direction of the arrow 33 in Fig. 2, a portion of the apparatus being broken away for sake of clearness and the cover being shown in cross section;

Fig. 4 is a bottom plan view of the relay the cover being in position;

Fig. 5 is a view in the direction of the arrow 5 in Fig. 2, the cover being removed; and

Fig. 6 is a wiring use of the relay in system.

Referring to the drawings the relay mounting bracket includes a flat base 21 from which are bent two parallel side portions 22 and two end portions 23 which terminate in apertured ears 24 adapted to receive screws for attaching the relay to a machine frame such as the frame of a dynamo 25 indicated diagrammatically in Fig. 6. The edges '26 of the sides 22 and the surfaces of the cars 24 are grooved to conform with the cylindiagram showing the the battery charging drical outer surface of a dynamo frame.

The base portion 21 insulatingly supports terminal bars and 31 receiving terminal screws 32 and 33, and a contact bracket 34 connected by rivet 35 with terminal bar 30, an L-shaped magnet frame 36 and a magnet core 37 which extends through the frame core and the terminal 1924. Serial No. 703,528.

39 is located between the terminal bars 30 and the base 21, and the washers 35 are insulated from base 21. A nonconducting strip 40 is located between the terminal bar 31 and the base 21 and between base 21 and a washer 41 retained upon the end of the core 37 by a nut 42 engaging the threaded end 43 of core 37. A washer 45 and the parts 38, 21, 40 and 31 are secured between the heads of rivets 44, and the swedged ends 46 of these rivets.

Thus it is apparent that the magnet bars 30 and 31 and the contact bracket 34 are insulatingly supported by the base 21.

Between the core head 50 of core 37 and the magnet frame 36 there are located stop bracket 51 and nonconducting discs 52 and 53. Between these discs are located a series magnet winding 54 and the shunt magnet winding 55 shown diagrammatically at 56. One end of the magnet winding 55 is attached at 56 to the core 37 and the other end is grounded by soldering at 57 to a lug extending from the base 21 of the bracket 20. Where the relay is installed in an automobile it is mounted upon the frame of a generator which is mounted upon the engine. Thus the winding 55 is grounded upon the frame of the vehicle. One end 58 of the winding 54 is electrically connected with the terminal bar 31 and the other end 59 of winding 54 is electrically connected with the magnet frame 36.

Frame 36 includes a leg 60 extending substantially parallel to the core 37. .The leg 60 is tapped to be engaged pass through holes in washers 62, 64 and 65 and through slots 66 in aflexible plate or leaf spring 67 attached by riveting to the leg 68 of armature 69 said leg 68 being approximately parallel to the leg 60 of magnet frame 36.

The magnetic circuit of the relay therefore includes a stationary part including core 37 and frame 36 having pole faces which are in different planes, namely the top face of core head 50 and the side surface of leg 60. The armature 69, or movable member of the magnetic circuit includes parts extending adjacent the pole faces, and the crossysectional area of the air gap between legs 68 and 60 is at least as great as the cross-sectional area by screws 61 which I of the air gap adjacent the core head 50, and

the armature 69 and frame 36, thereby tending to concentrate flux at the air gaps and to prevent magnetic leakage. It will be noted that the armature 69 and frame 36 are L- shaped with a leg of one overlapping the leg of another, and with the free legs (horizontally disposed in the drawings) substantially parallel. By virtue of the slots 66 and screws 61, the extent of overlap of the hingedly connected legs and hence the air gap adjacent bolt head 50 can be varied.

Armature 69 carries a contact 70 for engaging contact 71 carried by the contact racket 34. The stop bracket 51 is provided with a bendable portion 7 2' for engaging the free end of a leaf spring7 3 riveted at 74; to the armature 69. Thebracket 51 is provided with a bendable hook portion 75 adapted to extend over into the path of motion into the armature 69. I As shown in Fig. 2 the hook 75 servesas astop to limit the retraction of armature 69 from the core 37. By bending the hook 7 5 relative to the core 37 the maximum gap between the contact points can be varied.

y bending the spring stop 72 into various positions relative to the core 37 the tension applied by spring 73 can be varied.

The terminal 32 is connected-with a battery 80 which is grounded upon the vehicle frame and terminal 33 is connected with the dynamo 25 which is grounded also upon the vehicle frame. Below certain generating speeds the ma netism produced by current flowing throug the winding 54; alone will be insuflicient to attract the armature 69 and to close the contacts 70 and 71. Above a certain engine speed the contacts will be closed and thereafter held closed by reason of current flowing through the magnet winding. I The 0 eration of thereverse current is well known t erefore it is deemed suflicient to state that so long as the generator 1s charging the battery the contacts 7 O and 71 will remain closed a and when the generator stops the contacts will be opened due-to reversal of current in the winding 54.

' It is desirable that the contact pressure between the contacts and 71 be relatively great in order that a good electrical connection will be maintained between the generator and battery regardless of variations in generating speed between certain limits. It is'desirable that a magnet circuit of the relay be such as to minimize losses in magnetism. It will be noted therefore that the tween the stationary and movable parts of the magnet circuit are of a comparatively large cross-sectional area. variations in the width of the air gap will not so seriously afiect the magnetism of the relay. In order to accomplish this result certain portions of the magnet frame and armature overair gap be- Therefore slight A lap one another, the overlapping portions being 60 and 68, so as to provide an air gap of the necessary cross-sectional area. Another advantage resulting from this improvement of the magnetic circuit of the relay is that the relay cover shown at 90-and which fits over the mounting bracket 20 may be constructed of magnetic material such as sheet steel without substantially affecting the operation of the relay. Since the magnetic circuit concentrates the flux and tends to prevent leakmagnetic body near the age the placing of a substantially afiect its relay magnet does not operation.

To adjust initially the minimum air gap between the core head 50 and the armature 69 the screws 61 are loosened, a shim having a thickness equal to the minimum air gap desired is placed between the core and armature and the armature 69 is moved so that the contacts 70 and 71 are in engagement and the armature is in engagement with the shim. Then the screws tween the contacts when open will be suflicient to insure interruption of the electrical circuit between the battery and generator. The spring stop 72 is adjusted to vary the spring tension a plied to the armature 69 in-order to vary t e contact closing period ofthe relay relative to the operation of the generator.

While the forms of embodiment of the invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows 1. A relay comprising, lectromagnet winding, a magnet core extending through the winding, a magnet frame supporting the core and having a branch extending outside the winding substantially parallel to the core, an L-shaped armature having one leg overlapping the branch of the magnet frame a substantial amount and closely adjacent thereto and having a leg extending adjacent one end of the core, means hingedly connecting the magnet frame branch with the armature leg adjacent thereto, said ding for moving of said hinge means provi overlapping armature leg toward the magarmature moves to- 61 are tightened. When this adjustment is made, there will be in combination, an

extent of overlapping to 1y spaced therefrom and tending adjacent one end of the core, and a flexible plate for hingedly securing the magnet frame branch and overlapping armature leg and so constructed and arranged that, as the armature moves toward the core, the overlapping armature leg will move toward the magnet frame branch, and contacts controlled by the armature.

3. A relay comprising, in combination, a magnetic circuit including spaced, overlapping stationary and movable L-shaped members; a flexible blade securing the over-lapping members together so as to provide an air gap therebetween; adjustable means securing the flexible blade to one of said members for varying the extent of overlapping between said members; a winding for energizing said circuit; and a contact actuated by the movable member.

4. A relay comprising, in combination, a magnetic circuit including stationary and movable L-shaped members placed with a leg of one overlapping the leg of the other, and the free legs of said members being substantially parallel, and including a core attached to one free leg and extending toward the other free leg; a blade spring connecting the overlapping legs and normally providing an air gap therebetween; means adjustably securing the blade spring on one of said overlapping legs, and constructed and arranged for varying the extent of overlapping to vary the cross-sectional area of the air gap between said legs and to vary the air gap between the core and one of the members; a winding for energizing said circuit; and a contact actuated by the movable member.

5. A relay comprising, in combination, a magnetic circuit including stationary and movable L-shaped members placed with a leg of one overlapping the leg of the other, and the free legs of said members being substantially parallel, and including a core attached to one free leg and extending toward the other free leg; a leaf spring hinge connecting the overlapping legs and providing an air gap between said legs; means for varying the vary the air gap be tween the core and one of the members and to vary the cross-sectional area of the air gap between the overlapping legs; a winding for energizing said circuit; and a contact actuated by the movable member.

6. A relay comprisim in combination, a

magnetic circuit including stationary and having a leg exmovable L-shaped members placed with a leg of one overlapping the leg of the other, the free legs of said members being substantially parallel, and including a core attached to one free leg and extending toward the other free leg; a leaf spring hinge secured to one member on the side opposite the air gap and conmeeting the overlapping legs; means for varying the length of the hinged connection between said members to vary the air gap between the core and one of the members as well as to vary the cross-sectional area of the air gap between the legs; a winding for energizing said circuit; and a contact actuated by the movable member.

7. A relay comprising an electromagnet having a core; an armature attractable toward the core; a leaf spring fixed at one end to the armature to retract the armature from the core; a bracket slotted to provide separately bendable side by side portions one-of which provides an adjustable stop for limiting the retraction of the armature, the other providing an adjustable stop engaged by the free end of the spring to vary the tension thereof; and a contact controlled by the movement of the armature.

8. A relay comprising, in combination, a magnetic circuit including stationary and movable L-shaped members placed with the leg of one overlapping the leg of the other; a blade spring connection between the overlapping legs; a core having one end attached to the free leg of the stationary member and its other end terminating adjacent the free leg of the movable member; and means for adj usting the blade spring connection be tween the members to vary the distance between the end of the core and the free leg of the movable member.

9. A relay comprising an electromagnet having a core; an armature attractable toward the core; a leaf spring fixed at one end to the armature to retract the armature from the core; a bracket having separate portions, each one of which is bendable for purposes of adjustment without affecting the adjustment of the other portion, the one portion providing an adjustable stop for limiting the retraction of the armature, the other providing an adjustable stop engaged by the free end of the spring to vary the tension thereof; and a contact controlled by the movement of the armature.

In testimony whereof I hereto aflix my signature.

FRANK H. PRESCOTT.

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