US2519558A - Thermostatic switch - Google Patents

Thermostatic switch Download PDF

Info

Publication number
US2519558A
US2519558A US64326A US6432648A US2519558A US 2519558 A US2519558 A US 2519558A US 64326 A US64326 A US 64326A US 6432648 A US6432648 A US 6432648A US 2519558 A US2519558 A US 2519558A
Authority
US
United States
Prior art keywords
lever
switch
resilient
contact
plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US64326A
Other languages
English (en)
Inventor
Flight Theodore Nicholas
Wilson William Harry
Chinn Arthur John
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rheostatic Co Ltd
Original Assignee
Rheostatic Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rheostatic Co Ltd filed Critical Rheostatic Co Ltd
Application granted granted Critical
Publication of US2519558A publication Critical patent/US2519558A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H5/00—Snap-action arrangements, i.e. in which during a single opening operation or a single closing operation energy is first stored and then released to produce or assist the contact movement
    • H01H5/02—Energy stored by the attraction or repulsion of magnetic parts

Definitions

  • This invention relates to thermostats embodying a magnetic snap action switch and in which the thermally sensitive member actuating the switch comprises a tube or rod of relatively high thermal expansion material associated with a rod or'tube of low coeificient of expansion, and more particularly to thermostatic switches embodying a magnetic snap action switch of the type described in the specification of our copending application No. 39,276, filed July-17, 1948.
  • thermostats of this type are to control electric water heaters, and in such apparatus the space available for the switch head of the thermostat is very limited. It is also required that the temperature adjustment provided on the thermostat be in the form of a rotatable knob in the switch head located concentrically with the stem of the instrument.
  • the magnetic snap action switch of this invention consists of a resilient switch member carrying two iron armatures positioned one on each side of a permanent magnet, and so adjusted for movement that one armature remains closer to the magnet than the other in both the open and closed positions of the switch.
  • This adjustment of armatures produces a magnetic bias acting as a closing force between switch contacts, one of which is carried by the resilient switch member, the co-acting contact being arranged with screw adjustment in a supporting plate.
  • FIG. 2 showing a thermostat constructed in accordance with this invention
  • Fig. 2 is a plan view with the casing broken away
  • Fig. 3 an isometric view of the resilient switch lever with its attached armatures and contact.
  • Figures 4 and 5 show an elevation and plan of another embodiment of this invention. Similar parts in Figures 1, 2, 4 and 5 are indicated by the same reference numerals.
  • a thermally sensitive stem comprising a tube 2 of brass or similar metal of high thermal expansion into which is screwed at the end remote from the base i a nickel iron rod 3, having a low expansion coefficient.
  • Clamping posts 4, i screwed into the base i carry spacing washers 5, between which washers are held the magnet support plate 6, the resilient switch lever l, and fixed contact plate 8.
  • the position of the armatures i2, i3 relative to magnet H, and the travel of the moving contact [4 is set by adjustment of contact i5 and back stop 2 I.
  • Figure 4 shows an embodiment of the invention in'which the metal base i, the insulation 9 and the metal parts 5 below-the switch lever l in the first embodiment are replaced by a block 25 of insulating material such as steatite. Short posts 26, 26', fixed into the base block 25, clamp the switch parts to the base.
  • the terminals (not shown in Figure l) but actually carried on the outside of the case are, in the embodiment shown in Figures 4 and 5, disposed within the cover as shown at 28, 28, access being obtained to the terminals through suitably placed holes in the outer enclosing cover.
  • Rod 3 has mounted at its upper end a collar i3 adapted to move within a chamber as in a rigid lever l6.
  • Chamber has contact risers BB at its lower end which are contacted by shoulder l9 during downward movement of rod 3 in response to temperature increase.
  • Rigid lever it is iulcrumed at point on contact plate 8 and has a pip i! at its lower side to impart pressure to switch lever '5.
  • Rigid lever E5 is of electrical insulating material to avoid making permanent electrical connection between contact plate 8 and resilient switch lever 1.
  • the effective fulcrum of the spring switch lever l is at a point 7' where lines drawn as extensions to slots 21, 27 and shown dotted in Fig 3 intersect the centre line of the lever, taken through the contact M.
  • the point of application of pressure under pip H is, therefore, between the contactsv and the fulcrum and acts to open the contacts with increasing temperature.
  • knob l8 accessible from the outside of the thermostat casing to adjust the operating temperature of the thermostat. Rotation of knob It causes rotation of rod 3 and, because of the threaded engagement between rod 3 and tube 2, a relative longitudinal movement therebetween. By rotating knob I8 in such direction as to cause movement of rod 3 and hence shoulder 59 downwardly toward the switch pack, the temperature at which the switch opens is decreased, and by rotating knob H3 in the opposite direction the temperature at which the switch opens is increased.
  • An electric thermostat comprising a base, a clamping post extending from the base, a first rigid plate and a resilient lever clamped on said post in spaced superposed relation, a permanent magnet fixed to said plate, an armature assembly including a pair of spaced armatures mounted on said lever and disposed in fixed relation to each other respectively on opposite sides of said permanent magnet and spaced therefrom, a second rigid plate clamped on said post on the side of said lever opposite said first rigid plate, a rigid lever having a point at one end bearing on said second plate and a point at its other end bearing on said resilient lever, a contact fixed to said second rigid plate, a contact actuated by the resilient lever and adapted to engage the contact fixed to said second plate, an actuating member engaging said rigid lever intermediate said points and adapted to move said rigid lever to actuate said resilient lever and the contact actuated thereby, and means for limiting the movement of the armature assembly with respect to the permanent magnet so that one ar- 4 mature remains closer to the magnet than the other armature in
  • An electric thermostat comprising a base, a pair of spaced clamping posts extending from the base, a first rigid plate and a resilient lever clamped on said posts in spaced superposed relation, a permanent magnet fixed to said plate, an armature assembly including a pair of spaced armatures mounted on said lever and disposed in fixed relation to each other respectively on 0pposite sides of said permanent magnet and spaced therefrom, a second rigid plate clamped on said posts on the side of said lever opposite said first rigid plate, a rigid lever having a point at one end bearing on said second plate and a point at its other end bearing on said resilient lever, a
  • An electric thermostat comprising a magnet, a movable resilient lever, a pair of armatures carried by said resilient lever for movement therewith and disposed on opposite sides of said magnet at unequal distances therefrom in switchclosed position, a fixed contact, a cooperating contact carried by said resilient lever, a, second lever fulcrumed at one point fixed with respect to said contact and at another point on said resilient lever, a thermostatically-controlled member positioned to engage said second lever,

Landscapes

  • Thermally Actuated Switches (AREA)
US64326A 1947-12-09 1948-12-09 Thermostatic switch Expired - Lifetime US2519558A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB32489/47A GB632904A (en) 1947-12-09 1947-12-09 Improvements in electric thermostats

Publications (1)

Publication Number Publication Date
US2519558A true US2519558A (en) 1950-08-22

Family

ID=10339374

Family Applications (1)

Application Number Title Priority Date Filing Date
US64326A Expired - Lifetime US2519558A (en) 1947-12-09 1948-12-09 Thermostatic switch

Country Status (5)

Country Link
US (1) US2519558A (ja)
BE (1) BE486196A (ja)
CH (1) CH271496A (ja)
FR (1) FR976366A (ja)
GB (1) GB632904A (ja)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2707215A (en) * 1951-10-18 1955-04-26 Rheostatic Co Ltd Safety cut-outs for electrically heated appliances
US3207877A (en) * 1959-03-02 1965-09-21 Satchwell Controls Ltd Thermostatic switch with permanent magnet induced snap action

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB882876A (en) * 1959-03-02 1961-11-22 Rheostatic Co Ltd Improvements in temperature responsive magnetic snap-action switches
DE1195852B (de) * 1960-12-09 1965-07-01 Christian Buerkert Temperaturbegrenzer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB437826A (en) * 1934-05-26 1935-11-06 Harold Curtice Sanders Improvements in thermally-operated electric switches
US2183745A (en) * 1936-07-31 1939-12-19 Landis & Gyr Ag Thermostatic temperature regulator
US2291501A (en) * 1936-05-14 1942-07-28 Automatic Control Corp Differential adjuster

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB437826A (en) * 1934-05-26 1935-11-06 Harold Curtice Sanders Improvements in thermally-operated electric switches
US2291501A (en) * 1936-05-14 1942-07-28 Automatic Control Corp Differential adjuster
US2183745A (en) * 1936-07-31 1939-12-19 Landis & Gyr Ag Thermostatic temperature regulator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2707215A (en) * 1951-10-18 1955-04-26 Rheostatic Co Ltd Safety cut-outs for electrically heated appliances
US3207877A (en) * 1959-03-02 1965-09-21 Satchwell Controls Ltd Thermostatic switch with permanent magnet induced snap action

Also Published As

Publication number Publication date
GB632904A (en) 1949-12-05
CH271496A (de) 1950-10-31
BE486196A (ja)
FR976366A (fr) 1951-03-16

Similar Documents

Publication Publication Date Title
USRE24268E (en) Zuckerman
US2707738A (en) Midget thermostatic switch
US2394920A (en) Control device
US2519558A (en) Thermostatic switch
US2137073A (en) Thermostatic control system
US2085557A (en) Control device
US2061419A (en) Temperature control device
US2421538A (en) Thermostatic switch
US2044729A (en) Control device
US2390145A (en) Electric switch
US4107638A (en) Thermostat
US2162296A (en) Sensitive control device
US2154042A (en) Thermostatically controlled electric heating appliance
US2529941A (en) Thermostatic switch
US3418617A (en) Snap-acting, cycling, thermostatic switch
US3359389A (en) Bimetal snap switch with disconnect lever to prevent contacts from permanently welding
US2870314A (en) Control device
US2740879A (en) Temperature-regulated electric hotplates
US3413584A (en) Thermoresponsive switch
US2326239A (en) Electrothermally operated circuit controller
US1914675A (en) Thermostat
US3309476A (en) Quick acting make-and-break microswitch
US2303911A (en) Thermostat mechanism
US2644873A (en) Thermostatic and circuit breaker device
US2737555A (en) Thermostat