US1983076A

US1983076A - Thermostatic switch

Info

Publication number: US1983076A
Application number: US701714A
Authority: US
Inventors: Benjamin E Getchell
Original assignee: Trumbull Electric Manufacturing Co
Current assignee: Trumbull Electric Manufacturing Co
Priority date: 1933-12-09
Filing date: 1933-12-09
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

1934- B. E. GETCHELL THERMOSTATIC SWITCH Filed Dec. 9, 1933 INSULATION ETCHELL,

BENJAMI INVENTOR .E G

Patented Dec. 4, 1934 g g j 1,983,076

. THEBMOSTATIC swrron Getchell, Plalnville,

Com, assignor to The Trumbull Electric Manufacturing Comparry, Plainville, Conm, a corporation of Connecticut .Application December 9, 1933, Serial No. 701,714

5 Claims.

My invention relates to'improvements in the invention of my former Patent 1,928,484.

Constructions of this character under some conditions develop difliculties which it is my present object to overcome.

One object is to provide a construction which is more positive in its action.

Another object is to provide a construction which can be made very sensitive.

Another-object is to provide a construction which cannot be warped out of shape by subjection to abnormal temperature changes. a

Another object is to provide a simple form of construction which can be made and assembled in such a way as to produce reliable and dependable .movements under predetermined temperature-conditions. I

In carrying out the invention I provide a warping thermostatic strip or arm with-a spring biased hinged switch member at'its end as in my former patent and enclose one end 01' the snapping spring by a cup-like washer which is supported by. a knife edge or equivalent arrangemen The bi-metallic thermostatic strip. in this case is supported by one end of -a bar which projects from the insulating basemand this bar serves not only as a support buts-as an abutment to limit the warping action of the arm. Additional stops are also preferably provided to. limit the action of the arm away from the supporting bar. The arm, as in my former patent, is "provided with -means for adjusting or varying its action.

Fig. 1 is a plan view of one form of device embodying my invention with the parts in the-closed circuit oron position.

' Fig..2.is a side view and partial section of the same.

Fig. 3 is a transverse section on the plane of the line 3-3 of Fig. 2.

.Fig. 4. is an enlarged fragmentary sectional view showing the contact members separated.

Fig. .5 is an exploded perspective view showing the movable end of, the thermostatic arm, the

abutment washer and the movableswitch-member.

The parts are preferably supported by base '7 which also carries

circuit terminals

8 and 9 for the stationary and movable switch contacts respectively. 'The stationary contact 10 is secured to the terminal 8 and projects from the base at a substantially right angle. The movable switch contact member 11 is hinged to the movable end of the bi-metallic thermostatic arm or strip 12 whose other end is secured to and supported by I the abutment bar 13. This bar is secured to the base as, for instance, by riveted

portions

14 and 15. The arm is secured to the bar in any suitable manner as, for instance, by a screw or rivet 16 and an adjustment screw 1'1 is provided for giving an initial set or direction to the warping arm 12. This bar 13 extends substantially the entire length of the thermostatic arm so as to limit the warping movement of the arm in that direction. On the opposite side of the arm I preferably provide stops 18 and I9.

The hinged contact member 11 is connected to the thermostatic arm by a hook-like portion 20 which embraces the cross piece 21 so as to permit the arm 11 to swing about this cross piece. The spring 22 surrounds a part of the contact finger between the shoulders 23 and the washer 24. This washer is provided with grooves 25 to receive the knife-like tip 26 of the thermostatic arm.

The washer is preferably provided with a flange 27 which surrounds the larger end of the spring 22 so as to preventrelative displacement. The stationary abutment 28 is provided opposite the contact portion 10 so that the switch member 11 is limited in its movement between the

parts

10 and 28. a

While I have shown the part 28 as of insula tion it is obvious that it might be made conductive to constitute another circuit terminal.

As above pointed out while the construction of my former patent has desirable characteristics there 'are certain conditions under which such a device may not function as intended. For instance, if we assume that the switch member 11 is moved into the position shown in Fig. 1 in response to a decrease in temperature, a fur-- ther or excessive drop in temperature may cause the thermostatic element 12 to continue to bow in an arcuate form in such a manner as to snap the switch member to the open circuit position which is directly contrary to its intended function. abutment bar 13 above the thermostatic arm such an excessive warping action is prevented.

The present construction also more accurately relates the hinged switch member 11 to the thermostatic arm by reason of the knife edge support of the washer 24 on the end of the arm and further by reason of the lateral flange of the washer which confines the large end of the spring.

It will also be seen that by the present construction I provide circuit terminals which are riveted directly to the supporting members for the respective switch contacts so that there is By providing the stationary no likelihood of a poor electrical connection 1be-' ing'established by defective screws or the like.

I claim: v

1. A thermostatic device including an insulatingbase, a supporting abutment bar carried by the base, a bi-metallic arm secured at one end to said bar and movable at the other end toward and from said bar, said'bar serving to limit the warping movement of said arm in one direction, a stop limiting the movement of said arm away from said bar, a stationary contact and a spring pressed switch member hinged to the movable end of said am and adapted to engage said stationary contact. r

2. A thermostatic device including an insulating base, a supporting abutment bar carried by the base and extending edgewise thereupon, a bi-metallic arm secured at one end to said bar and movable at the other end towardand from said bar and parallel with said base, a stop limiting the movement of said arm away from said bar, two stationary abutments and a spring pressed switch member end of said arm and adapted to snap between said abutments.

3. A thermostatic switch including a supporting base, a thermostatic arm having one end supported by said base and having a knife edge at the opposite end, a switch member having a hinged connection with said arm including a hinged to the movablev posed between the spring washer having a grooved portion for engagement with said knife edge and a cupped portion, and a direction, stops near the opposite ends for limiting the movement of said arm away from said bar, a stationary contact and a spring pressed switch member hinged to the movable end of said arm and adapted to engage said stationary contact.

5. A thermostatic switching device including a stationary contact, a movable contact, a bi-me-j tallic arm supported at one of its ends and having its opposite end free .to move for actuating said movable contact, a compression spring actuated by said arm for imparting a snap action to the contact movement and a cup-shaped washer for seating one end of said spring and dis- I and arm to permit uniform action of the spring, said washer having a grooved portion forming a pivot seat for the movable end portion of saidbi-metallic arm.

BENJAMIN E. GETCHEIL.