US2567361A - Manually operable thermostatic switch assembly - Google Patents

Description

spt. 11, 1951 F. R. BEAN 2,567,361

MANUALLY OPERA'BLE THERMOSTATIC SWITCH ASSEMBLY original Fi1ed oct. 19, 15542 Patented sepa n', 195i MANUALLY OPERABLE THERMOSTATIC SWITCH ASSEMBLY Frank Robert Bean, Rochester, N. Y., assignor to Fasco Industries, Inc., a corporation of New York Original application October 18, 1942, Serial No. 462,504, now Patent No. 2,520,873, dated August 29, 1850. Divided and this application November 7, 1949. Serial No. 125,990

2 Claims. (Cl. 20o-113) This application is a division of my co-pending application Serial No. 482,504-1ed- October 19, 1942, for Manually Operable Thermostatic Switch Assembly, which application-has resulted in Patent No. 2,520,873, dated August 29, 1950. The present invention relates to a manually operable thermostatic switch assembly and more particularly to the combination with a thermostatic switch assembly of an intermediate member held in inoperative position by a thermostatic switch arm, movable to render said switch assembly inoperative when said switch arm attains a predetermined temperature, and manually operable member for returning said intermediate member to its inoperative position.

The primary object of the invention is the combination comprising a thermostatic switch assembly having a normally closed thermostatic switch arm, a normally operative intermediate member which is held in inoperative position by said switch arm but normally movable after opening of said switch arm to prevent normal closing thereof, and a manually operable member normally spaced from said intermediate member, located to limit the movement thereof, and for returning the same to its ineffective position.

Other and further objects of the present invention will be suggested to those skilled in the art by the accompanying disclosure.

The foregoing and other objects of the invention are embodied in the combination of a thermostatic switch assembly having a normally closed switch arm, a manually operable member, and an intermediate means movable by said manually movable member. Said intermediate means or member is adapted, after said switch arm has been thermally operated, to render said switch arm inoperative, and is returned to inoperative position by resetting movement of said manually operable member. Y

Reference is hereby made to the accompanying drawings wherein similar reference characters designate similar elements and wherein:

Fig. 1 is a vertical longitudinal section of a i thermostatic switch assembly including a manually operable member according to the invention.

Pig. 2 is a horizontal section on the line I-I of Fig. 1.

Figs. 3 and 4 are respectively longitudinal and transverse vertical sections on the lines 8-8 and l-I of Fig. 2 and all showing said thermostatic switch assembly.

In general the manually operable thermostatic switch assembly according to the invention comprises a switch means including a thermostatic switch arm, a manually operable member, and an intermediate member. The manually operable member is spring held in one position spaced from said intermediate member in its ineffective position, located to abut and limit the movement of said intermediate member, and movable to return said intermediate member to its ineffective position. Said manually operable member when moved bears against and controls the position of said intermediate member which determines the operability of the switch arm according to the position of the manually operable member and/or the thermal condition of the thermostatic switch arm. Said switch assembly may be mounted upon an instrument panel or similar support by means of a mounting plate carrying a casing and an insulating base.

The switch assembly may be mounted upon an instrument panel or similar support by means of a mounting plate 20 which is provided with holes 2|. A casing 22 having an open side is fastened to said plate 20 in any suitable manner as by spot welding. A base 24 of any suitable insulating material covers the open side of said casing 22 and is held in position as by a plurality of bent tongues 25.

The casing 22 has an insulating liner 8| and the manually operable member is a push button 82 which extends through an opening in the mounting plate 20. As best shownin Fig. 3, a

central insulating plate 83 has an edge 84 fitting into a slot in the top of casing 22, is provided with a recess 85, and has a projection 88 at the bottom of said recess 85. The' push button 82 is internally recessed to receive a spring 81 which has its other end bearing upon a washer 88 and centered by projection 86. Lateral flanges 88 on push button 82 engage the top of casing 22 to limit the movement of push button 82 by said spring 81.

A pair of terminal straps. and 8| each extend through base 24 and into complementary recesses within central insulating plate 83 and each carries a terminal clamp 82 and screw 83 for connection to circuit conductors. Insulating side plates 84 are fastened at each side of central plate 83 by rivets 85 and 86 and are each provided with an aperture 81 and a hole 88. A pair of stationary contacts 28 are fastened to terminal strap each on opposite sides thereof as by spot welding and are each within an aperture 81 of side plates 9|. A pair of terminal studs indicated generally as |02 have ends |00 smaller in diameter than the width of terminal strap 9| and fitting into a hole I 0| in terminal strap 8|. Each of said studs |02 is provided with a groove |03 and has flanges 88 swaged and thereby expanded into the respective side plates 94, preferably at the inner sides thereof. A pair oi thermostatic switch arms 3| are fastened to respective terminal studs |02 as by spun over or riveted heads |04. Said thermostatic switch arms 3| are preferably composed of bimetallic sheet material and are of the snap acting type. As best shown in Fig. 1 each switch arm 3| is provided with a pair of diverging slots 34 and is deformed with gathered portions 35 at the outer ends of each slot 34 so that each arm 3| is dished or curved longitudinally as shown in Fig. 2 and curved transversely as shown in Fig. 4. Such deformaf'- tion or mechanical stress in said switch arms 3| causes abrupt reversal in a known manner when said arms 3| are heated to or above a predetermined temperature. An angle piece |05 is attached by rivets |06 to each of said switch arms 3| and each has a portion overhanging the ends thereof.

The intermediate member comprises a separator normally movable between the open contacts but held out of such position by the switch arm 3| when the contacts are closed. A pair of insulating sectors |01 are each pivotally mounted upon each of said terminal studs |02. each has a corner |08 adjacent push button 82 and each has an extension |09. Spring members each has one end encircling groove |03 and anchored in terminal stud |02 and each has their other end inserted into a hole in sector |01, see Fig. 2. When the contacts 28 and 3'6 are normally closed. said extension |09 bears against the edge of angle piece by reason of the action of spring member |0. The tension of spring members ||0 is such that the pressure of extensions |09 upon the edges of angle pieces |05 is not suficient to affect the thermal operation or movement of thermostatic switch arms 3|.

When the current in the circuit connected to the switch assembly shown is below the critical value, the switch arms 3| are in normally closed position, the contacts 28 and 36 are engaged, and each of the extensions |09 on insulating sectors |01 are pressed against the edges of angle pieces |05. However, when said current exceeds said critical value the thermostatic switch arms 3| are moved to open position, contacts 28 and 36 are separated, and angle pieces |85 are moved out of engagement with extensions |09 of insulating sectors |01 and spring members ||0 move said sectors |01 to bring said extensions |09 between the contacts 28 and 38. Even though the operating characteristics of or current passing through switch arms 3| are not precisely the same, as soon as one pair of contacts 28 and 36 are opened the entire current will pass through the other switch arm 3| and immediately heat it above its critical value and cause it to open. The corners |08 of sectors |01 are arranged to abut against the bottom of p ush button 82 so that the extensions |09 can not be moved beyond the interrupting position between the contacts 28 and 36.

Cooling of the switch arms 3| does not return the switch assembly to operative condition because the insulating sectors 01 or extensions |09 thereof remain between the contacts 28 and 36 until the push button 82 l is fully depressed. Downward movement of said push button 82 moves corners |08 of insulating sectors |01 in a counter-clockwise direction until extensions |09 are beyond the edges oi' angle pieces |05. Since switch arms 3| have cooled oil? and if the abnormal condition in the circuit has been cleared,

said switch arms 3| will normally close contacts 28 and 36 and angle pieces |05 will move into blocking position with respect to extensions |09. Of course, if the abnormal condition has not been cleared switch arms 3| will again open and insulating sectors |01 will be moved to place extensions |09 between the contacts.

It will kbe obvious to those skilled in the art that the duplex switch assembly of Figs. 1-4 may be provided as a single unit or may be provided with separate halves for controlling two separate or alternative circuits related so that only a single manual reset is necessary.

Since many variations o! the invention are possible. the present disclosure shall be construed in an illustrative sense and the scope of the invention is dened by the claims which follow.

Having now particularly described my invention, what I desire to secure by Letters Patent of the United States and what I claim is:

l. In a manually operable thermostatic switch assembly, the combination comprising a support, a contact mounted on said support, a bimetallic switch blade having a portion mounted upon said support, having a movable portion carrying a second contact, and normally closing said contacts when said bimetallic switch blade is below a predetermined temperature, an intermediate member normally movable to a position to separate said contacts and releasably held in an ineffective position by said switch blade when the same vis below said predetermined temperature, and a manually operable member normally spaced from and independent of. saidr intermediate member when the same is in its ineffective position, located to abut and limit the movement of said intermediate member to its position to separate said contacts, and movable uto return said intermediate member to its ineffective position.

2. In a manually operable switch assembly, the combination comprising a support, a pair of contacts, one of which is mounted upon said support, a bimetallic switch blade mechanically stressed per se for abrupt reversal when heated above a predetermined temperature, having a portion mounted upon said support, having a Vmovable portion carrying the other of said contacts, and normally closing said contacts when said bimetallic switch blade is at temperatures below said predetermined temperature, an abutment on the movable portion of said switch blade and movable therewith, an intermediate member normally movable to a position between said contacts and held in an ineffective position by said abutment when said contacts are closed, and a manually operable member normally spaced from and independent of said intermediate member when the same is in its ineiective position, and located to abut and limit the movement of said intermediate member to its position between said contacts, and movable to return said intermediate member to its ineffective position for re-engagement with said abutment when said switch blade is below said predetermined temperature. FRANK ROBERT BEAN.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,373,128 Freese Mar. 29, 1921 1,891,015 Rich Dec. 13, 1932 2,262,205 Schachtner Nov. 11, 1941

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