[go: up one dir, main page]

WO1992016003A1 - Ameliorations concernant des interrupteurs a reaction thermique - Google Patents

Ameliorations concernant des interrupteurs a reaction thermique Download PDF

Info

Publication number
WO1992016003A1
WO1992016003A1 PCT/GB1992/000417 GB9200417W WO9216003A1 WO 1992016003 A1 WO1992016003 A1 WO 1992016003A1 GB 9200417 W GB9200417 W GB 9200417W WO 9216003 A1 WO9216003 A1 WO 9216003A1
Authority
WO
WIPO (PCT)
Prior art keywords
switch
housing
body part
contact
predetermined
Prior art date
Application number
PCT/GB1992/000417
Other languages
English (en)
Inventor
Keith Fletcher
Paul Mitchell
Original Assignee
Otter Controls Limited
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 Otter Controls Limited filed Critical Otter Controls Limited
Publication of WO1992016003A1 publication Critical patent/WO1992016003A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/002—Thermally-actuated switches combined with protective means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/52—Thermally-sensitive members actuated due to deflection of bimetallic element
    • H01H37/54—Thermally-sensitive members actuated due to deflection of bimetallic element wherein the bimetallic element is inherently snap acting
    • H01H37/5427—Thermally-sensitive members actuated due to deflection of bimetallic element wherein the bimetallic element is inherently snap acting encapsulated in sealed miniaturised housing
    • H01H37/5436—Thermally-sensitive members actuated due to deflection of bimetallic element wherein the bimetallic element is inherently snap acting encapsulated in sealed miniaturised housing mounted on controlled apparatus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/126—Automatic release mechanisms with or without manual release actuated by dismounting of circuit breaker or removal of part of circuit breaker

Definitions

  • thermally-responsive electrical switches concerns improvements relating to thermally-responsive electrical switches and more particularly relates to thermostatic electrical switches and thermal cut-outs as used for example in tumble dryers, washing machines, coffee percolators, domestic heaters, cookers, central heating boilers etc.
  • Background of the Invention A commonly known type of thermally-responsive electrical switch manufactured by many manufacturers comprises a dished bimetal disc mounted at one axial end of a generally cylindrical housing and arranged to open a set of switching contacts via the inter ediacy of a push rod when, in response to an over-temperature condition, the bimetal disc moves to an oppositely curved configuration with a snap action.
  • the bimetal disc is commonly arranged to reset automatically when its temperature falls, thereby enabling the switching contacts to remake, though it could be arranged if desired to require to be manually reset.
  • Such switches in some applications are mounted so as to have the bimetal disc in close thermal contact with the surface of a member whose temperature is to be monitored, for example the head plate of an electric immersion heating element, and in other applications may be mounted to be responsive to air temperature or to radiant heat.
  • thermally responsive electrical switches of the type outlined above have been relatively unsophisticated and have not been designed to take advantage of concepts which are becoming relatively commonplace in other situations, such as for example the concept of secondary protection which we have pioneered and successfully developed in the field of providing element over-temperature protection in water boiling vessels, particularly the modern generation of plastics bodied water boiling jugs.
  • secondary or back-up protection is provided as a means to ensure proper protective functioning of the control in the event, however unlikely, that the control fails to respond at a primary level to an overtemperature condition.
  • Exemplary arrangements for providing primary and secondary levels of over-temperature protection for the heating elements of electrically powered water boiling vessels are disclosed in our British Patents Nos. 2117568 and 2194099.
  • the object of the present invention in one of its aspects, is thus to provide a thermally responsive switch, generally of the above-described type, which incorporates secondary protection.
  • the present invention aims to provide such a switch, preferably but not essentially incorporating secondary protection, which has the feature that it will go open circuit in the event of the switch becoming detached from its mounting, for example on account of mounting screws becoming loose.
  • a thermally-responsive switch generally of the type described hereinbefore comprises inner and outer body parts which are movable with respect to each other, spring means urging the inner part towards a predetermined positional relationship with the outer part, and means responsive to the proper mounting of the switch for effecting relative movement between said inner and outer parts against the action of said spring means, the arrangement being such that an electrical circuit through said switch can not be effected with said inner and outer parts in said predetermined positional relationship irrespective of the condition of the bimetal.
  • the outer body part of the switch has first and second terminals captured therein and, within the said part, first and second contact-carrying leaf-springs are welded to respective ones of the terminals, one of said leaf-springs being arranged to be acted upon by the push-rod of the switch when the bimetal moves to its overtemperature condition, and the other of said leaf-springs constituting the aforesaid spring means acting upon the inner body part and being arranged so that its contact is positioned so as to be capable of co-operating with the contact carried by the other spring for switching operations only when the switch is properly mounted and the inner body part urges the respective leaf-spring into the requisite position.
  • a similar leaf- spring arrangement is utilized but, additionally or alternatively, that one of the two leaf-springs that is acted upon by the inner moulding is arranged to make electrical contact with a respective one of the terminals only when the switch is properly mounted.
  • the arrangement may for example be such that the positional relationship between the inner and outer members that is established when the switch is properly mounted is conditional upon the temperature of one or other of said parts being below such an elevated temperature as to cause the respective part to deform under the action of the aforesaid spring means and consequentially render the switch open circuit.
  • Figures 1A to IE show various stages in the manufacture of a first embodiment of the present invention, the various component parts of the switch being separately illustrated;
  • FIGS. 2A to 2C show enlarged sectional views of the switch of Figures 1A to IE under different operational conditions
  • Figures 3A and 3B show exploded views, from different directions, of a second embodiment of the present invention.
  • Figures 4A to 4D show sectional views of the switch of Figures 3A and 3B under different operational conditions.
  • FIGS 5A to 5C schematically illustrate different mounting arrangements for the switch of Figures 3A and 3B.
  • Figure 1A shows first and second brass terminal parts 1 and 2 which are captured in an outer moulded plastics switch body part 3 by insert moulding, portions of the terminals 1 and 2 extending into the interior of the part 3 and being exposed therein.
  • Figure IB shows first and second leaf-springs 4 and 5 which are spot welded to the terminal parts 1 and 2 respectively where they are exposed within the body part 3.
  • the leaf-springs 4 and 5 carry respective switch contacts 6 and 7 only one of which can be seen in Figure IB.
  • Figure 1C shows a moulded plastics inner body part 8 which is sized to make an easy sliding fit within outer body part 3 of the switch, a push-rod or slide 9 which is adapted to be inserted into a rectangular passageway formed in inner body part 8, and a dished bimetal disc 10.
  • the inner body part 8 is formed with three legs 11 which themselves are formed with enlarged portions 12 which define seats for the edge of the bimetal disc 10.
  • the slide 9 is bifurcated at one end, the end which extends inwardly of the switch, and this end of the slide sits astride the radially-inwardly directed limb 4' of the leaf-spring 4. At its other end, the slide 9 has a protrusion which is adapted to engage the centre of the bimetal disc 10.
  • a metal retaining cap 13 is shown in Fig. ID, such cap 13 being arranged to be fitted over the open end of the outer body part 3 and clenched thereto and having a central opening 14 providing access to the bimetal disc 10 and a plurality of circumferential apertures 15 providing an easy clearance fit for the legs 11 of the inner body part 8.
  • Figure 1E-1 the ends of the legs 11 protrude through the apertures 15 in the free standing condition of the switch.
  • Figure 1E-2 shows the completed switch as viewed from the side opposite to the view of Figure 1E- 1.
  • Figures 2A to 2C show cross-sectional views of the completed switch, Figure 2A showing the switch in free standing condition, Figure 2B showing the switch properly mounted to a surface whose temperature is to be monitored, and Figure 2C showing the overtemperature condition of the switch.
  • Figure 2A in the free standing condition of the switch the contacts 6 and 7 carried by the leaf-springs 4 and 5 are broken and the inner part 8 of the switch takes up a position which, as viewed in the figures, is towards the bottom of the switch and has the legs 11 projecting through the apertures 15 in the retaining cap 13.
  • FIGS. 3A and 3B show an alternative and presently preferred embodiment of the present invention, and the same reference numerals are used to designate the parts in these figures as were used to designate similar parts in the foregoing description of the first embodiment.
  • a main or outer moulded plastics body part 3 has captured terminals 1 and 2 which extend into the hollow interior of the body part 3 where they contact leaf- springs 4 and 5 respectively.
  • An inner moulded plastics body part 8 is adapted to be slidably received within the outer body part 3 and is formed with a through- aperture for accommodating a push-rod or slide 9, and a dished bimetal disc 10 and a retaining cap 13 complete the component count for the switch.
  • the leaf-spring 4 is generally D-shaped or semi-circular and carries the switch contact 6 at one end of its diametral part, an extension or enlargement 20 at the other end of such part being provided for contacting switch terminal 1 within the hollow interior of outer body part 3.
  • the other leaf-spring 5 is generally annular with external projections 21 (the purpose whereof will be explained below) , an enlarged portion whereat it carries the switch contact 7, an enlarged portion 22 with a cut-out designed to enable the leaf-spring 5 to be held captive on a post 23 formed as an integral part of the inner switch body part 8, the post 23 passing with interference through the cut-out, and an internal projection 24 (the purpose whereof will also be explained below) .
  • Mounting lugs 25 are provided on the outer switch body part 3 as shown, and co-operating mounting lugs 26 are provided on the inner body part 8, the lugs 26 being guided by slots 27 formed in the main body part 3 and feet 28 being formed on the lugs 26.
  • a post 29 is formed on the inner body part 8 underlying the internal projection 24 of the leaf spring 5.
  • the interior of the main switch body part 3 is formed to define a seating for the leaf-spring 4 -which has its enlarged part 20 spot welded into electrical contact with the switch terminal 1.
  • the remainder of the leaf-spring 4 is constrained against movement in its own plane but can be flexed by the action of push-rod 9 which is responsive to the condition of bimetal disc 10.
  • the leaf-spring 5 is designed so that its outwardly projecting portions or ears 21 locate in grooves 30 formed in the main body part 3 and its curved circumferential periphery on both sides of the ears 21 are unsupported and have a clearance from the adjacent internal wall of the body part 3; the leaf-spring 5 is thus capable of being bowed between mounting locations defined by engagement of the ears 21 with the inner ends of the grooves 30, that is to say generally about a notional straight line extending between switch contact 7 and the mounting enlargement 22.
  • this cross-sectional view shows the free-standing condition of the switch.
  • Leaf- spring 4 is welded at its enlarged portion 20 to switch terminal l and is held generally in a position to be moved by the action of push-rod 9 when it is operated by temperature-responsive operation of bimetal disc 10.
  • Leaf-spring 5 is held with its ears 21 lodged in the bottoms of the grooves 30, and the post 29 of the inner body part 8 bears against the underside of the inwardly- directed spring extension 24 with a sufficient spring force to keep the body part 8 in contact with the periphery of the bimetal disc 10.
  • the switch contacts 6 and 7 are spaced apart, and additionally there is a spacing between the spring extension 24 and a contact defining portion 31 of switch terminal 2.
  • FIG. 4B shows the switch in the condition where the inner body part 8 has been raised through approximately half of its movement, and in this condition the switch contacts 6 and 7 on the two leaf-springs 4 and 5 make contact but there is still no contact made between the extension 24 of leaf-spring 5 and the contact defining portion 31 of switch terminal 2.
  • FIGS 3A and 3B which operates as described with reference to Figures 4A to 4D thus also achieves the preferred objects of the present invention, namely to provide secondary or back-up protection in a switch package wherein the switch will go open circuit in the event that it becomes inadvertently detached from its intended mounting location.
  • Figures 5A to 5C show schematic views of the switch in stand free, surface mounted and bulkhead mounted situations and it will be seen that versions of the switch responsive to surface temperature or to the air temperature within a duct for example need only have different length legs 28 on the inner switch body part.

Landscapes

  • Thermally Actuated Switches (AREA)

Abstract

Interrupteur à réaction thermique qui comprend un boîtier cylindrique sur le bord duquel est monté un disque bilame à action instantanée disposé de manière à faire fonctionner une paire de contacts au sein du boîtier d'interrupteur par l'intermédiaire d'une tige-poussoir. Une partie interne de l'interrupteur peut se déplacer axialement au sein du boîtier d'interrupteur par l'intermédiare d'une tige-poussoir. Une partie interne de l'interrupteur peut se déplacer axialement au sein du boîtier d'interrupteur et appuie contre un premier ressort à lames établissant le contact situé au sein de l'interrupteur, un second ressort à lames établissant le contact subissant l'action de la tige-poussoir. Le premier ressort à lames pousse la partie interne de l'interrupteur vers l'extérieur du boîtier de l'interrupteur et c'est seulement lorsque l'interrupteur est monté correctement que la partie interne est engagée dans le boîtier d'interrupteur de manière à pousser le premier ressort à lames dans une position dans laquelle il peut coopérer avec le second ressort à lames lors des opérations d'interruption. Ainsi l'interrupteur va-t-il ouvrir le circuit s'il est démonté. En outre, la partie interne de l'interrupteur peut être conçue pour se déformer lors d'une surchauffe excessive de manière à fournir une protection supplémentaire dans l'éventualité peu probable où la bilame ne fonctionnerait pas.
PCT/GB1992/000417 1991-03-11 1992-03-09 Ameliorations concernant des interrupteurs a reaction thermique WO1992016003A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB919105111A GB9105111D0 (en) 1991-03-11 1991-03-11 Improvements relating to thermally-responsive switches
GB9105111.0 1991-03-11

Publications (1)

Publication Number Publication Date
WO1992016003A1 true WO1992016003A1 (fr) 1992-09-17

Family

ID=10691352

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/000417 WO1992016003A1 (fr) 1991-03-11 1992-03-09 Ameliorations concernant des interrupteurs a reaction thermique

Country Status (2)

Country Link
GB (1) GB9105111D0 (fr)
WO (1) WO1992016003A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999053513A1 (fr) * 1998-04-14 1999-10-21 Otter Controls Limited Ameliorations relatives aux commandes de temperature d'elements chauffants electriques
US6583710B2 (en) * 2000-11-13 2003-06-24 Wako Electronics Thermostat
EP2259282A3 (fr) * 2009-06-01 2014-06-25 Eaton Corporation Interrupteur de circuit incluant un boîtier moulé fabriqué en polymère de cristal liquide
CN110867341A (zh) * 2019-11-07 2020-03-06 太平洋电子(昆山)有限公司 一种接触式双金属片温控器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0014102A1 (fr) * 1979-01-29 1980-08-06 Eaton S.P.A. Thermostat
EP0041823A1 (fr) * 1980-06-06 1981-12-16 THE GENERAL ELECTRIC COMPANY, p.l.c. Interrupteur thermosensible
EP0049209A2 (fr) * 1980-09-30 1982-04-07 Siemens Aktiengesellschaft Commutateur de protection de construction compacte comprenant une broche de déclencheur
EP0255347A2 (fr) * 1986-07-28 1988-02-03 Otter Controls Limited Regulateur thermique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0014102A1 (fr) * 1979-01-29 1980-08-06 Eaton S.P.A. Thermostat
EP0041823A1 (fr) * 1980-06-06 1981-12-16 THE GENERAL ELECTRIC COMPANY, p.l.c. Interrupteur thermosensible
EP0049209A2 (fr) * 1980-09-30 1982-04-07 Siemens Aktiengesellschaft Commutateur de protection de construction compacte comprenant une broche de déclencheur
EP0255347A2 (fr) * 1986-07-28 1988-02-03 Otter Controls Limited Regulateur thermique

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999053513A1 (fr) * 1998-04-14 1999-10-21 Otter Controls Limited Ameliorations relatives aux commandes de temperature d'elements chauffants electriques
EP1517346A1 (fr) * 1998-04-14 2005-03-23 Otter Controls Limited Perfectionnement concernant la régulation thermique pour un élement électrique chauffant
US6583710B2 (en) * 2000-11-13 2003-06-24 Wako Electronics Thermostat
EP2259282A3 (fr) * 2009-06-01 2014-06-25 Eaton Corporation Interrupteur de circuit incluant un boîtier moulé fabriqué en polymère de cristal liquide
CN110867341A (zh) * 2019-11-07 2020-03-06 太平洋电子(昆山)有限公司 一种接触式双金属片温控器

Also Published As

Publication number Publication date
GB9105111D0 (en) 1991-04-24

Similar Documents

Publication Publication Date Title
EP0255347B1 (fr) Regulateur thermique
CA1265831A (fr) Commandes thermosensibles
EP1075701B1 (fr) Ameliorations relatives a la commande d'elements chauffants electriques
US4752671A (en) Electric immersion heating elements and controls therefor
US4754252A (en) Thermostatic switch with improved cap disc assembly
EP0950340A1 (fr) Dispositif servant a rechauffer un liquide
WO1992016003A1 (fr) Ameliorations concernant des interrupteurs a reaction thermique
EP1586102A2 (fr) Ameliorations d'une commande d'elements de chauffage electrique
EP1072048B1 (fr) Ameliorations relatives aux commandes de temperature d'elements chauffants electriques
EP1610354B1 (fr) Montage d'un déclencheur bimétallique en forme d'assiette
EP1173863B1 (fr) Ameliorations concernant des commandes thermosensibles
EP1249851B1 (fr) Améliorations relatives a la commande d'éléments chauffants électriques
EP1642309B1 (fr) Ameliorations apportees a des unites de regulation thermique
GB2372159A (en) Cordless kettle connector with bimetallic overtemperature controls
GB2217160A (en) Electric immersion heaters and thermally-sensitive controls therefor
GB2410615A (en) Mounting for a bimetallic actuator
GB2252674A (en) Thermally responsive electrical switches
GB2248724A (en) Thermally responsive controls
EP0565577B1 (fr) Interrupteur electrique a sensibilite thermique
GB2592869A (en) Thermal control
GB2220547A (en) Electric immersion heaters

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): GB US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU MC NL SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
122 Ep: pct application non-entry in european phase