US2436633A - Thermostatic switch for controlling electric circuits - Google Patents

Thermostatic switch for controlling electric circuits Download PDF

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Publication number
US2436633A
US2436633A US563239A US56323944A US2436633A US 2436633 A US2436633 A US 2436633A US 563239 A US563239 A US 563239A US 56323944 A US56323944 A US 56323944A US 2436633 A US2436633 A US 2436633A
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United States
Prior art keywords
contacts
switch
electromagnet
thermostatic switch
metal
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Expired - Lifetime
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US563239A
Inventor
Curzon Thomas
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CAV Ltd
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CAV Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
    • H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
    • H01H77/04—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrothermal opening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
    • B23G1/00—Thread cutting; Automatic machines specially designed therefor
    • B23G1/02—Thread cutting; Automatic machines specially designed therefor on an external or internal cylindrical or conical surface, e.g. on recesses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q5/00—Driving or feeding mechanisms; Control arrangements therefor
    • B23Q5/22—Feeding members carrying tools or work
    • B23Q5/34—Feeding other members supporting tools or work, e.g. saddles, tool-slides, through mechanical transmission
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/64—Contacts
    • H01H37/66—Magnetic reinforcement of contact pressure; Magnet causing snap action
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q2705/00—Driving working spindles or feeding members carrying tools or work
    • B23Q2705/10—Feeding members carrying tools or work
    • B23Q2705/18—Feeding other members supporting tools also feeding working spindles supports
    • B23Q2705/182—Feeding other members supporting tools also feeding working spindles supports in lathes

Definitions

  • This invention relates to thermostatic protective switches, for use in electricity distributing systems, and has for its object to provide improved switches of the kind adapted to open in the event of a fault or other condition causing an abnormal current to flow in a circuit containing the switch, and also adapted to be prevented from automatically reclosing.
  • Figure 1 is a sectional side view of a switch mechanism embodying the invention
  • Figure 2 is a diagram illustrating the electrical cnnections of the switch mechanism.
  • an electromagnet d is secured in any convenient manner to a supporting plate 72 having a central aperture, and is enclosed by a sheet metal or other casing m having an open end secured to the supporting plate, the other end of the casing being closed.
  • the electromagnet d comprises a yoke '0, a winding'e, and a spring loaded armature f, the latter having one end hingedly attached by a resilient metal strip 1) to the inner end of the yoke, and having a contact a on its other end.
  • a bl-metal strip 0 which at one end is secured to a metal piece q, the other end of the bi-metal strip having mounted on it a contact b adapted to co-operate with the contact a.
  • the ends of the electromagnet winding e are electrically connected to the metal piece q and the electromagnet yoke 0 respectively.
  • the metal piece q is situated in part between and electrically insulated from one side of the electromagnet yoke o and a second metal piece 1, the latter being secured and electrically connected to the said yoke by screws 8 which also serve to secure the firstmentioned metal piece in position.
  • a third metal piece it is secured by screws u to the other side of the electromagnet yoke 0, but is electrically insulated therefrom in any convenient manner.
  • the second and third metal pieces r extend through the closed end of the casing m, and are provided at their outer ends with terminal screws 1) for connection to the circuit to be controlled.
  • a push-pull switch 2' having a pair pair of complementary movable contacts r.
  • the fixed contacts are respectively secured to the metal pieces q, t at positions near the supporting plate a, and are formed at their adjacent sides with V-shaped recesses 31 for accommodating of fixed contacts w and aiiti complementary parts of the movable contacts r.
  • the latter are interconnected by a resilient metal bridge piece 2, and are operable by an axially movable stem 2 which passes through the central aperture in the supporting plate n and is provided at its outer end with a finger piece 3 made from insulating material.
  • the finger piece 3 is formed with a tubular extension 4 which is slidable in a fixed tubular guide 5 on the supporting plate n.
  • the stem 2 passes through a central hole in the bridge piece 2 and is surrounded by a pair of helical compression springs 6 through which movement can be imparted by the stem to the bridge piece for actuating the movable contacts 3:, one of the springs being situated between the bridge piece and the finger piece 3, and the other being situated between the bridge piece and a head 1 on the inner end of the stem.
  • a pair of insulating pieces 8 Secured to the supporting plate 11 and situated between the latter and the fixed contacts w are a pair of insulating pieces 8 which at their adjacent sides are also formed with V-shaped recesses 9 for accommodating the movable contacts :r.
  • the contacts a, b are normally closed, and when in this condition they short-circuit the electromagnet winding e which is of relatively high resistance.
  • the con tacts a, b remain closed so long as normal conditions exist in the said circuit, but in the event of a short-circuit or other condition causing abnormal heating of the strip 0 the said contacts are separated, whereupon current flows through the Winding e and excites the electromagnet d.
  • This causes rapid and complete separation of the contacts a, b and prevents reclosure thereof in consequence of the strip 0 cooling,
  • the main switch 2 is opened.
  • the electromagnet d then ceases to act, and the cooled strip 0 allows the contacts a, b, to come together again.
  • the position of the contact b may be adjusted by a set screw l carried by the metal piece q and acting on the bi-metal strip 0.
  • a thermostatic switch of the kind specified having in combination a pair of normally closed and independently movable contacts, a heat responsive device, and an electromagnet having its winding permanently connected across said contacts, one of said contacts being movable by said heat responsive device to cause separation of said contacts and the other contact bein arranged to be attracted and actuated by said electromagnet, so that in the event of separation of said contacts by said heat responsive device said contacts are held apart by said electromagnet.
  • thermostatic switch as claimed in claim 1, in which the normally closed and independently movable contacts are respectively carried by a bi-metal strip forming the heat responsive device and by an armature forming a part of the electromagnet.
  • a thermostatic switch as claimed in claim 1 and having in an electric circuit containing the normally closed and independently movable con tacts, a controlling push-pull switch, the two switches being formed as a unitary structure.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Thermally Actuated Switches (AREA)
  • Control Of Direct Current Motors (AREA)

Description

Feb 24, T. CURZON THERMOSTATIC SWITCH FOR CONTROLLING ELECTRIC CIRCUITS Filed NOV. 13, 1944 l NVENTOR THoMAs CURZON IHI Patented Feb. 24, 1948 THERMOSTATIC SWIT LING ELECTRI Thomas Curzon, Acton, London,
CH FOR CON TROL- C CIRCUITS England, assignor to C. A. V. Limited, London, England Application November 13, 1944, Serial No.
In Great Britain October 1, 1943 4 Claims. (Cl. 20088) This invention relates to thermostatic protective switches, for use in electricity distributing systems, and has for its object to provide improved switches of the kind adapted to open in the event of a fault or other condition causing an abnormal current to flow in a circuit containing the switch, and also adapted to be prevented from automatically reclosing.
In the accompanying sheet of explanatory drawings,
Figure 1 is a sectional side view of a switch mechanism embodying the invention, and Figure 2 is a diagram illustrating the electrical cnnections of the switch mechanism.
In carrying the invention into effect as shown an electromagnet d is secured in any convenient manner to a supporting plate 72 having a central aperture, and is enclosed by a sheet metal or other casing m having an open end secured to the supporting plate, the other end of the casing being closed. The electromagnet d comprises a yoke '0, a winding'e, and a spring loaded armature f, the latter having one end hingedly attached by a resilient metal strip 1) to the inner end of the yoke, and having a contact a on its other end. At a position adjacent to the armature there is arranged within the casing m a bl-metal strip 0 which at one end is secured to a metal piece q, the other end of the bi-metal strip having mounted on it a contact b adapted to co-operate with the contact a. The ends of the electromagnet winding e are electrically connected to the metal piece q and the electromagnet yoke 0 respectively. The metal piece q is situated in part between and electrically insulated from one side of the electromagnet yoke o and a second metal piece 1, the latter being secured and electrically connected to the said yoke by screws 8 which also serve to secure the firstmentioned metal piece in position. A third metal piece it is secured by screws u to the other side of the electromagnet yoke 0, but is electrically insulated therefrom in any convenient manner. The second and third metal pieces r, extend through the closed end of the casing m, and are provided at their outer ends with terminal screws 1) for connection to the circuit to be controlled.
For electrically interconnecting the first and third metal pieces q, t, I employ a push-pull switch 2' having a pair pair of complementary movable contacts r. The fixed contacts are respectively secured to the metal pieces q, t at positions near the supporting plate a, and are formed at their adjacent sides with V-shaped recesses 31 for accommodating of fixed contacts w and aiiti complementary parts of the movable contacts r. The latter are interconnected by a resilient metal bridge piece 2, and are operable by an axially movable stem 2 which passes through the central aperture in the supporting plate n and is provided at its outer end with a finger piece 3 made from insulating material. The finger piece 3 is formed with a tubular extension 4 which is slidable in a fixed tubular guide 5 on the supporting plate n. The stem 2 passes through a central hole in the bridge piece 2 and is surrounded by a pair of helical compression springs 6 through which movement can be imparted by the stem to the bridge piece for actuating the movable contacts 3:, one of the springs being situated between the bridge piece and the finger piece 3, and the other being situated between the bridge piece and a head 1 on the inner end of the stem. Secured to the supporting plate 11 and situated between the latter and the fixed contacts w are a pair of insulating pieces 8 which at their adjacent sides are also formed with V-shaped recesses 9 for accommodating the movable contacts :r.
- The contacts a, b, are normally closed, and when in this condition they short-circuit the electromagnet winding e which is of relatively high resistance. Assuming that the main switch 1' is closed and that the metal pieces r, t, are connected to the circuit to be controlled, the con tacts a, b remain closed so long as normal conditions exist in the said circuit, but in the event of a short-circuit or other condition causing abnormal heating of the strip 0 the said contacts are separated, whereupon current flows through the Winding e and excites the electromagnet d. This causes rapid and complete separation of the contacts a, b and prevents reclosure thereof in consequence of the strip 0 cooling, When removing the fault the main switch 2 is opened. The electromagnet d then ceases to act, and the cooled strip 0 allows the contacts a, b, to come together again.
When the switch 2' is closed its movable contacts a: engage the recesses 11 in the fixed contacts 20. To open this switch a pull is exerted on the finger piece 3. The effect of this is to compress the spring 6 arranged between the bridgepiece z and the head 1 of the stem 2 until this spring causes the movable contacts a: to be disengaged from the recesses 11 in the fixed contacts w and moved into engagement with the recesses 9 in the insulating pieces 8. Reclosure of the switch 2 is effected by exerting a push on the finger piece 3. This causes the other spring 8 to be compressed until it causes the movable contacts a: to be disengaged from the recesses 9 and re-engaged with the recesses 11. It will be seen therefore that both the opening and closing movements of the contacts a: are effected rapidly under spring action.
If desired the position of the contact b may be adjusted by a set screw l carried by the metal piece q and acting on the bi-metal strip 0.
Whilst I prefer to employ bi-metal strip for the separation of the normally closed contacts on account of its simplicity and convenience, I may in some cases employ any other convenient thermally deformable means for separating the contacts.
Having thus described my invention what I claim as new and desire to secure by Letters Patent is:
. 1. A thermostatic switch of the kind specified, having in combination a pair of normally closed and independently movable contacts, a heat responsive device, and an electromagnet having its winding permanently connected across said contacts, one of said contacts being movable by said heat responsive device to cause separation of said contacts and the other contact bein arranged to be attracted and actuated by said electromagnet, so that in the event of separation of said contacts by said heat responsive device said contacts are held apart by said electromagnet.-
2. A thermostatic switch as claimed in claim 1, in which the normally closed and independently movable contacts are respectively carried by a bi-metal strip forming the heat responsive device and by an armature forming a part of the electromagnet.
3. A thermostatic switch as claimed in claim 1 and having in an electric circuit containing the normally closed and independently movable con= tacts, a controlling push-pull switch, the two switches being formed as a unitary structure.
4. A thermostatic switch as claimed in claim 1 and having in an electric circuit containing the normally closed and independently movable con tacts, a controlling push-pull switch comprising in combination a pair of fixed contacts, a pair of resiliently interconnected movable contacts adapted to co-operate with said fixed contacts, an operating member and springs through which movement can be imparted to said resiliently interconnected movable contacts under the action of said operating member, the two switches being formed as a unitary structure.
THOMAS CURZON.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 29,015 Siemens Bros. -1904 1,336,418 Broeger Apr. 13, 1920 1,561,240 Johnston Nov. 10, 1925 1,564,938 Chandeysson Dec. 8, 1925 1,763,649 Goetz June 17, 1930 2,087,216 Betz July 13, 1937 2,313,969 Riche Mar. 16, 1943 2,338,731 Morse Jan. 11, 1944 FOREIGN PATENTS Number Country Date 471,946 Germany 1929
US563239A 1943-10-01 1944-11-13 Thermostatic switch for controlling electric circuits Expired - Lifetime US2436633A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB16149/43A GB568714A (en) 1943-10-01 1943-10-01 Improvements relating to thermostatic switches for controlling electric circuits

Publications (1)

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US2436633A true US2436633A (en) 1948-02-24

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US563239A Expired - Lifetime US2436633A (en) 1943-10-01 1944-11-13 Thermostatic switch for controlling electric circuits

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US (1) US2436633A (en)
BE (1) BE461932A (en)
CH (1) CH266751A (en)
DE (1) DE856329C (en)
FR (1) FR914648A (en)
GB (2) GB568714A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2505691A (en) * 1948-04-07 1950-04-25 Richard F Spurck Fractional horsepower motor and components thereof
US2528777A (en) * 1946-08-21 1950-11-07 Mcquay Norris Mfg Co Electromagnetic switching means
US2539179A (en) * 1946-10-21 1951-01-23 Cav Ltd Engine starting mechanism
US2714859A (en) * 1949-10-17 1955-08-09 Claude C Klemme Electrical apparatus, as for model railroads, including resonant relay and switches therefor
US3633143A (en) * 1967-10-16 1972-01-04 Matsushita Electric Ind Co Ltd Magnetically controlled thermal relay

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1038639B (en) * 1955-10-21 1958-09-11 Cav Ltd Electric push-pull switch
DE1131785B (en) * 1960-08-09 1962-06-20 Licentia Gmbh Thermal release for electrical switchgear
DE1201900B (en) * 1962-08-17 1965-09-30 Licentia Gmbh Circuit breakers with high switching capacity, especially installation circuit breakers

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US29015A (en) * 1860-07-03 Improvement in apparatus for distilling sea-water
US1336418A (en) * 1917-01-26 1920-04-13 Splitdorf Electrical Co Circuit-controlling mechanism
US1561240A (en) * 1920-07-07 1925-11-10 Westinghouse Electric & Mfg Co Control apparatus
US1564938A (en) * 1922-04-29 1925-12-08 Marshall Electric Company Field regulator
DE471946C (en) * 1926-07-23 1929-10-30 Bbc Brown Boveri & Cie Magnetic-thermal overcurrent relay
US1763649A (en) * 1929-03-05 1930-06-17 William T Tassler Electric switch
US2087216A (en) * 1934-08-31 1937-07-13 Cons Gas Electric Light And Po Relay device
US2313969A (en) * 1940-08-03 1943-03-16 Micro Switch Corp Control apparatus
US2338731A (en) * 1942-11-19 1944-01-11 Gen Electric Circuit controller

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US29015A (en) * 1860-07-03 Improvement in apparatus for distilling sea-water
US1336418A (en) * 1917-01-26 1920-04-13 Splitdorf Electrical Co Circuit-controlling mechanism
US1561240A (en) * 1920-07-07 1925-11-10 Westinghouse Electric & Mfg Co Control apparatus
US1564938A (en) * 1922-04-29 1925-12-08 Marshall Electric Company Field regulator
DE471946C (en) * 1926-07-23 1929-10-30 Bbc Brown Boveri & Cie Magnetic-thermal overcurrent relay
US1763649A (en) * 1929-03-05 1930-06-17 William T Tassler Electric switch
US2087216A (en) * 1934-08-31 1937-07-13 Cons Gas Electric Light And Po Relay device
US2313969A (en) * 1940-08-03 1943-03-16 Micro Switch Corp Control apparatus
US2338731A (en) * 1942-11-19 1944-01-11 Gen Electric Circuit controller

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2528777A (en) * 1946-08-21 1950-11-07 Mcquay Norris Mfg Co Electromagnetic switching means
US2539179A (en) * 1946-10-21 1951-01-23 Cav Ltd Engine starting mechanism
US2505691A (en) * 1948-04-07 1950-04-25 Richard F Spurck Fractional horsepower motor and components thereof
US2714859A (en) * 1949-10-17 1955-08-09 Claude C Klemme Electrical apparatus, as for model railroads, including resonant relay and switches therefor
US3633143A (en) * 1967-10-16 1972-01-04 Matsushita Electric Ind Co Ltd Magnetically controlled thermal relay

Also Published As

Publication number Publication date
DE856329C (en) 1952-11-20
GB568714A (en) 1945-04-17
FR914648A (en) 1946-10-14
GB576821A (en) 1946-04-18
BE461932A (en) 1946-01-21
CH266751A (en) 1950-02-15

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