US2488055A - Thermostatic switch - Google Patents

Description

Nov. 15, 1949 A. R. DE PASCALE 2,488,055

THERMOSTATIC SWITCH Filed Aug. 15, 1947 FIJ--1 /7 E; E- E A TTOR/YE YS Patented Nov. 15, 1949 UNITED STATES PATENT OFFICE THERMOSTATIC SWITCH Angelo R. De Pascale., Scottsville, N. Y. Application August 15, 1947, Serial No. 768,721 Claims. (CL 20G-138) This invention relates to improvements in thermostatic switches particularly adapted for use in electric nre alarm systems for private dwellings, hotels, factories and other buildings.

An object of the invention is to provide an improved thermostatic switch of simple, light, compact, durable construction that can be produced at low cost and will be eflicient and reliable in operation. Y

Another object of the invention is to provide an improved thermostatic switch in which the thermostatic element and other switch parts will be well' protected against tampering and from interference due to accumulations of dust while at the same time the thermostatic element will be fully responsive to changes in temperature of air adjacent the switch.

Another object of the invention is to provide an improved thermostatic switch of the character referred to` that can be easily assembled;

vulai" construction, combination and arrangement of parts comprising the same will be understood from the hereinafter contained detailed description when considered in connection with the accompanying drawings forming part Fig. 8 is a detail section on the line I-l of I Fig. 3;

While a preferred embodiment of the invention is illustrated in the drawings, it will be understood that minor changes and modifications may be made in the particular construction shown and the invention may be embodied in other forms as will appeal to those skilled in the art and falling within the scope of the appended claims without departing from the spirit of the invention.

Referring to a detailed description of the particular-embodiment of the invention illustrated in the drawings, I designates a base formed of electrical insulating material, preferably plastic material. On the upper face of the base at one end and at one side thereof is a boss 2, the same being shown of rectangular shape in cross section. A bi-metallic thermostatic strip 3 is secured at one end to saidboss by bolts and nuts 4, 5, said bi-metallic strip extending along one side of the base' I to the opposite end thereof and having at its free end a contact stem l extending inwardly therefrom at right angles thereto. One of the bolts 4 has associated therewith a metal sleeve I suitablyvsecureddn a re cess in the boss 2, said bolt serving as a binding post to which is connecteda conductor wire 8, the end of the conductor wire being clamped between a nut 9 on said bolt and the metal sleeve 1. On the base I at the other end thereoi.' is a boss I0, which is provided with an interior chamber II extending linwardly from one end thereof and also with a bore I2 that ex- Ihereof and illustrating one embodiment of the invention.

In the drawings: Fig. 1 is a topplan view of a thermostatic switch constructed in accordance with the presthe line 1-.1 of F18. 63

tends inwardly from the oppositeend of the boss to said chamber. Suitably secured in a recess in the boss adjoining said -bore is a nut I3, and adjustably engaging said nut. for cooperation with the contact stem 6 of the thermostatic strip is a contact screw I4, the inner end portion of the latter and the end portion of the contact stem being both disposed within the y chamber I I' of the boss. As will be understood the lateral movement of the bi-metallic strip 3 due to changes in temperature, imparts a corresponding movement to the contact stem 6 to and from the inner end of the contact screw IL thereby closing the alarm circuit when the contact points meet and opening the alarm circuit'when the contacts separate. Byadjusting the contact screw Il, the switch may be set to open and close at the desired predetermined temperature. To facilitate the nice adjustment o! the contact screwv I 4 relatively to the contact stem 8,*the boss I0 may be provided with an elongated slot I5 for the insertion of an appropriate gauge to measure the distance between the contact points of the contact screw and stem. On the outer end portion of the contact screw I4 is a, nut I6 for securing a conductor Wire I'I to the contact-l screw, the conductor wire being clamped between said nut against the metal sleeve I3.

A shield is provided to protect the switch parts against tampering and also from interference by accumulations of dust. The shield designated generally I8 is of oblong shape and of substantially the same size as the base I. It comprises a fiat plate portion I9 of oblong shape to fit against the upper face of the base I, and a casing 20 integral with the flat plate portion I9 projecting above the upper face thereof, said casing extending along one end and along an adjoining side marginal portion of the plate portion, the casing being open at its under side and adapted to enclose the bosses 2 and the switch elements. The protective casing is substantially U-shaped in cross section, the same having a top Wall 2I, side walls 22, 23 and end Walls 24, 25. That portion of the protective casing 20 extending along the side of the base and enclosing the bi-metallic thermostatic strip is formed with vertical slots 26 providing openings for the passing of air into the casing adjacent the bi-metallic strip 3. After the contact screw I4 has been adjusted relatively to the contact stem 6 as desired, the protective shield is permanently secured to the base by rivets 21. 28 designates apertures extending through the at plate portion I9 of the shield and the base for attaching screws.

The shield is preferably formed from plastic material but it could be constructed of metal or any other suitable material. It may be transparent, translucent or opaque. When formed of transparent plastic material, a light strong structure is afforded that provides for ready in spection of the switch parts when the shield is .permanently secured to the base to prevent tampering.

What I claim is:

1. In a thermostatic switch, a substantially oblong shape base of insulating material, a boss on the upper face of the base at one end and at one side thereof, a bi-metallic strip secured at one end to said boss and extending to the other end of the base, said strip having a contact stem extending inwardly from its free end, a -bosson the base at the end thereof opposite to that at which the first mentioned boss islocated, a transversely extending adjustable con. tact screw mounted in said last mentioned boss to cooperate with the contact stem' of the bimetallic strip, and a shield member substantially oblong shape in plan having a at plate portion to t against the face ofthe base, and a( casing integral with said plate portion, projecting above the upper face thereof, said casing extending along one end and Aone side marginal portion of said plate portion, the casing being open at its under side and adapted to enclose said bosses and switch elements, and means for securing the shield member to the base.

2. In a thermostatic, switch, a substantially oblong shaped base Aof insulating material, a boss on the upper face of the base at one end and at one side thereof, a bi-metallic` strip securedy at one end to said boss and'extending to the other end of the base, said strip having a contact stem 4 extending inwardly from its free end at substantially right angles thereto, a boss on the base at the end thereof opposite to that at which the rst mentioned boss is located, a. transversely extending adjustable contact screw mounted on said last mentioned boss to cooperate with the contact stem of the bi-metallic strip, and a shield member oblong shape in plan and of substantially the same size as said base, said shield member having a fiat oblong shaped plate portion of substantial size to t against the face of the base, and a casing of inverted L -shape form integral with said plate portion projecting above the upper face thereof, said casing extending along one end and one side marginal portion of the plate portion and of the base, the casing being open at its under side and adapted toenclose said bosses and switch elements, Vand means passing through said at plate portion of the shield for securing the shield member to the base.

3. In a thermostatic switch, a substantially oblong shape base of insulating material, a, boss on the upper face of the base at one end and at one side thereof, a bi-metallic strip secured at one end to said boss and extending to the other end of the base, said strip having a contact stem extending inwardly from its free end, a boss on the base at the `end thereof opposite to that at which the first lmentioned boss is located, a transversely extending adjustable contact screw mounted in said last mentioned boss to cooperate with the contact stem of the bi-metallic strip,-A

and a shield member substantially oblong shape in plan having a flat plate portion to fit against the face of the base, and a casing integral with said plate portion projectingA above the upper4 face thereof, said casing extending along one end and one side marginal portion of said plate portion, the casing being open at its under side and adapted to enclose said bosses and switch elements, the part of said casing that encloses the loi-metallic strip havingslots at intervals along the same providing air inlets adjoining the thermostatic strip, and means for securing the shield member to the base.

4. In a thermostatic switch, a substantially oblong shape base of insulating material, a boss on the upper face of the base at one end and at one side thereof, a bi-metallic strip secured at one end to said boss and extending to the other end of the base, said strip having a contact stem extending inwardly from its free end, a boss on the base at the end thereof opposite to that at which the first mentioned boss is located, a transversely extending adjustable contact screw mounted in `said last mentioned boss to cooperate with the contact stem of the bi-metallic strip, and a shield member of substantially oblong shape in plan having a nat plate portion to t against the face of the base, and a casing integral with said plate portion projecting above the upper face thereof, said casing being of inverted L-shape form in plan-and rectangular shape in cross section and extending along one endV and the adjoining side marginal portion of said plate portion, the casing being open at its under side and adapted to enclose said bosses and switch elements, that part of the casing enclosfing the bi-metallic strip having slots in its opposite side walls at intervals along the same providing air inlets adjoining the thermostatic strip, and means for securing the shield member to the base. v

5. In a thermostatic switch, a substantially oblong shaped base of insulating material, a boss on the upper face of the base at one end and at s one side thereof, a bi-metallic strip secured at one end to said boss and extending to the other end of the base, said strip having a. contact stem extending 4inwardly from its free end at substantially right angles thereto, a boss on the base at the end thereof opposite to that at which the iirst mentioned boss is located, said boss having an interior chamber extending inwardly from one end thereof and also having a bore extending inwardly from its other end to said chamber, the outer end portion of said contact stem extending within the interior chamber of said boss, a transversely extending adjustable contactscrew on said base extending through said bore into said chamber and having aI contact at its outer end to cooperate with the contact stem of the thermostatic strip, a substantially oblong shaped shield member having a ilat plate portion to iit against the face of the base, a casing integral with said plate portion projecting above the upper face thereof, said casing extending along one end and the adjoining side marginal portion of the plate portion, the casing being open at its under side and adapted to enclose said bosses and switch elements, and means for securing the shield member to the base.

` ANGELO R. DE PASCALE.

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

UNITED STATES PATENTS .Number Name Date 582,093 Riley May 4, 189'? 1,044,270 Shaler Nov. 12, 1912 1,336,728 Christensen Apr. 13, 1920 1,612,114 Hall Dec. 28, 1926 1,822,472 Brady Sept. 8, 1931 1,845,049 Jarvis Feb. 16, 1932 2,074,141 Broune Mar. 16, 1937

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