EP0000635A1 - Lame à action brusque et sa méthode de fabrication - Google Patents

Lame à action brusque et sa méthode de fabrication Download PDF

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Publication number
EP0000635A1
EP0000635A1 EP78300146A EP78300146A EP0000635A1 EP 0000635 A1 EP0000635 A1 EP 0000635A1 EP 78300146 A EP78300146 A EP 78300146A EP 78300146 A EP78300146 A EP 78300146A EP 0000635 A1 EP0000635 A1 EP 0000635A1
Authority
EP
European Patent Office
Prior art keywords
arms
blade
contact element
contact
base portion
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.)
Granted
Application number
EP78300146A
Other languages
German (de)
English (en)
Other versions
EP0000635B1 (fr
Inventor
Guglielmo Rossi
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.)
Robertshaw US Holding Corp
Original Assignee
Ranco Inc
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 Ranco Inc filed Critical Ranco Inc
Publication of EP0000635A1 publication Critical patent/EP0000635A1/fr
Application granted granted Critical
Publication of EP0000635B1 publication Critical patent/EP0000635B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • H01H5/04—Energy stored by deformation of elastic members
    • H01H5/18—Energy stored by deformation of elastic members by flexing of blade springs
    • H01H5/20—Energy stored by deformation of elastic members by flexing of blade springs single blade moved across dead-centre position

Definitions

  • This invention relates to snap action switch blades.
  • An object of the present invention is to provide an improved snap-action switch blade which, compared with many types of known blade, is of simple construction lending itself readily to economic quantity production.
  • a snap action switch blade of resilient sheet metal comprising a base portion, an inwardly projecting tongue, an outwardly projecting tongue, two resilient legs projecting from opposite sides of the base portion and terminating beyond the inwardly projecting tongue in respective resilient arms which project laterally inwardly towards each other, and a contact element affixed to the two arms and interconnecting them in a stressed condition in which the arms are drawn together, causing a dish deformation of the base portion, and prestressing the blade for snap movement of the contact when an operating force is applied to one of the tongues while the end of the other tongue is anchored.
  • the contact element itself serves to interconnect the arms of the switch blade, avoiding the necessity to provide a separate bridging piece interconnecting the arms, with a contact affixed thereto.
  • the contact element interconnects the resilient arms at the outer ends of the two legs of the blade, serving both as an electrical contact and drawing the two arms together to stress the blade and predispose it for snap action. Since it is not necessary to affix a separate contact element to the blade, after . deformation thereof and interconnection of the arms, the blade construction is simplified considerably and is therefore potentially economical in mass production.
  • the outwardly projecting tongue terminates in a flat portion adapted 4 o be anchored to a fixed support, this flat portion having a greater width than the remainder of the outwardly projecting tongue.
  • this flat portion of the blade When the said flat portion of the blade is anchored to a fixed support the blade as a whole acts as a cantilever resisting elastically the operating force applied to the inwardly projecting tongue.
  • the elasticity of this mounting cantilever can be predetermined by appropriate choice of the length and width of the outwardly projecting tongue, to predispose the blade for monostable or bistable snap movement according to the practical application for which the switch is intended.
  • a further important feature of the switch blade according to the invention is that the resilience of the two laterally inwardly projecting arms to which the contact element is affixed affords a degree of elasticity in the mounting of the contact element, which serves to resist and dampen any tendency for "contact bounce" when the contact element closes upon a fixed contact in use of the switch blade.
  • the two laterally inwardly projecting arms terminate in end portions of enlarged width to which the contact element is affixed, the centre or contact area of the contact element being spaced from the longitudinal centreline of the two arms so that contact pressure exerted on the contact element causes torsional stress in the two arms.
  • the torsional stress which exists in the two arms carrying the contact element when the latter ia held by the switch blade against a fixed switch contact ensures that upon contact separation a wiping action takes place relative to the fixed switch contact, breaking any welds which may form in use of the switch blade.
  • This wiping action, and the effective damping of any This wiping action, and the effective damping of any tendency to contact bounce may be enhanced by so dimensioning the switch blade that the two laterally inwardly projecting arms which carry the contact element are narrower in width than the two legs of the switch blade upon which the arms are formed.
  • the contact element of the switch blade should se of a material which can easily be welded to the arms of the switch blade, while presenting a suitable contac surface.
  • the contact element of the switch blade comprises a base portion which is affixed to the two laterally inwardly projecting aris and an electrically conductive contact layer which is deposited on or bonded to the base portion.
  • the contact element may conveniently be of square or rectangular shape, severed from a continuous strip, each contict element being formed with two raised parallel ribs on its base portion along which the contact elements is welded to the arms of the blade.
  • the invention also comprehends a method of making the snap action switch blade herein defined comprising stamping or otherwise forming a flat blade bank fo resilient sheet metal with a base portion, hwardly and outwardly projecting tongues, two legs pro cting from opposite sides of the base portion and ex fnding generally ⁇ parallel to the inwardly projecting tongue, terminating beyond the latter in respective arms which project laterally inwardly towards each other, the inner ends of the said arms bein spaced from each other by a gap, anchoring the base portion of the blade blank while deforming the outer ends of the two legs laterally towards each other to reduce the gap between the arms and stress the blade, and affixing to the two arms a contact element which interconnects the arms and maintains the blade in its stressed condition.
  • the contact element would in practice preferably be affixed to the two arms by a welding operation, the steps of deforming the blade blank and welding the contact element in position being conveniently performed in an automatic sequence, using a suitable jig.
  • the two legs of the latter may be formed at their ends with laterally outwardly projecting lugs to which laterally inwardly directed forces are applied to deform the outer ends of the two legs laterally inwardly towards each other, prior to the affixing of the contact element to the laterally inwardly projecting arms carried by the legs.
  • the snap action switch blade shown in Figure 1 comprises a sheet of resilient sheet metal, for example beryllium copper having a thickness of 0.25 millimetre.
  • the blade is formed with a base portion 1, an inwardly projecting tongue 2, an outwardly projecting tongue 3, and two resilient legs 4, 5 projecting from opposite sides of the base portion 1, the legs 4, 5 bsing substantially parallel to each other and terminating beyond the end of the inwardly projecting tongue 3 in respective laterally inwardly projecting arms 6, 7.
  • the base portion 1, the tongues 2, 3 the legs 4, 5 and the arms 6, 7 are all formed integrally with each other from a single resilient metal sheet.
  • the two laterally inwardly projecting arms 6, 7 are interconnected by a contact element 8 which is welded to the two arms 6, 7, interconnecting them in a stressed condition in which the arms are drawn together, causing stressing of the two legs 4, 5 arid resulting in a sliglt dished deformation of the base portion, as illustrated in Figure 1.
  • the outwardly projecting tongue 2 terminates in a flat integral mounting tab 9 of greater width than the remainder of the tongue 2, the tab 9 having two holes 10 by means of which it can be anchored firmly to a fixed support, so that the entire blade projects cantilever-fashion from this. support.
  • the switch blade When mounted in this way, and prestressed for snap action as described above, the switch blade is predisposed to effect snap movement of the contact element 8 relative to the fixed blade support and, therefore, relative to a fixed switch contact (not shown) when an operating force is applied to the end of the inwardly projecting tongue 3.
  • the tongue 3 may be formed with a raised protuberance 11 near its free end, forming a well defined surface for engagement by a switch operating member (not shown) which applies an operating force indicated by the arrow P in Figures 1 and 4..
  • the switch blade can be designed so as to be monostable or bistable in operation.
  • the switch blade reverts to its original stressed condition when the operating force P is removed or falls below a further threshold value.
  • the application of the operating force P causes anap movement of the contact element 8 into engagement with a fixed contact (not shown) of a switch, and the subsequent release of the force P results in snap opening of the switch contacts.
  • the blade can be predisposed for bistable operation, whereby, once having undergone snap deformation from its original stressed condition ( Figure 1) it assumes a stable condition with the opposite dished deformation to that shown in Figure 1.
  • the flexural elasticity of the two legs 4, 5 and the arms 6, 7 serves to enhance the snap movement of the contact element 8 carried thereby by virtue of the inertia of the relatively massive contact element 8: before the instant of contact separation the legs 4, 5 and the arms 6, 7 will bend elastically, releasing their stored energy when the contact element 8 "unsticks" to cause rapid movement of the contact element 8 relative to the fixed contact.
  • Figure 2 shows a flat sheet metal blank 12 stamped in a single piece from resilient conductive material such as, for example beryllium copper sheet.
  • the legs 4, 5 are parallel to each other and to the central inwardly projecting tongue 3, and the outwardly projecting tongue 2 is coplanar with the inner tongue 3.
  • the two laterally inwardly projecting arms 6, 7 at the ends of the legs 4, 5 are also coplanar, and terminate in respective edges 13, 14 which converge towards the base portion 1 and which are separated by a suitable gap to allow the subsequent prestressing of the blade.
  • the edges 13, 14 converge at an angle of approximately 6 0 .
  • the two laterally inwardly projecting arms 6, 7 terminate in end portions 15, 16 of enlarged widtn, the two arms o, themselves in this embodimsmr than the respect
  • Two shallow outwardly projecting rounded lugs 17, 18 are formed at the ends of the respective legs 4, 5 adjoining the arms 6, 7.
  • the blade blank 12 shown in Figure 2 After stamping the blade blank 12 shown in Figure 2 and deforming the central inwardly projecting tongue 3 to form the raised protuberance 11, the blade blank is placed in a jig with the flat tab 9 anchored in a fixed support or clamp forming part of a jig which includes pneumatically operated pistons which act upon the external lugs 17, 18 of the blank to deform the legs 4, 5 inwardly towards each other, closing or substantially closing the gap between the edges 13, 14.
  • the pistons may be arranged to bring the edges 13, 14 into edge to edge abutment with each other, or alternatively may incorporate stops to reduce the size of the gap between the edges 13, 14 by a predetermined amount only.
  • the contact element 8 is of bimetal construction, having a base layer of suitable material capable of being welded to the blade blank 12.
  • the contact element is formed with two raised parallel ridges 19, 20 ( Figure 3).
  • the ridges 19, 20 are pressed into contact with the respective end portions 15, 16 of the blade blank upon assembly of the blade, and after inward deformation of the arms 6 and 7 towards each other the contact element 8 is welded to the end portions along the ridges 19, 20 by the passage of a suitable welding current between the contact element 8 and the blade itself, thereby securing the contact element 8 to the arms 6 and 7 and interconnecting the latter in a stressed condition of the blade.
  • Superimposed upon the base layer of the contact element 8 is a contact layer of silver cadmium oxide, or some other suitable conductive material,.
  • the contact element 8 may conveniently be cut from a continuous strip of the aforesaid bimetal, extruded with the raised ridges 19, 20 extending longitudinally, the strip being cut transversely of the ridges to form the contact element 8, without any subsequent finishing operation being necessary.
  • Such torsional deformation serves to absorb the kinetic energy of the contact element 8 upon closure of the switch contacts, acting in a shock- absorbing capacity and minimising the tendency for contact bounce to occur.
  • the torsional deformation and therefore the shock absorbing effect will be proportional to the kinetic energy to be absorbed.
  • the torsional deformation of the arms 6, 7 also has the effect of imparting a slight twisting action to the contact element 8 about a transverse axis parallel to the axis X-X of the arms 6, 7, resulting in a rocking or wiping movement of the contact element 8 upon the fixed contact prior to separation of the contacts and serving to break any welds between the contacts.
  • the contact element 8 in the switch blade of Figures 4 and 5 is on the opposite face of the blade from the contact element 8 in the embodiment of Figure 1: either position may be adopted for the contact element according to the switching requirement.

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  • Manufacture Of Switches (AREA)
EP19780300146 1977-07-15 1978-07-12 Lame à action brusque et sa méthode de fabrication Expired EP0000635B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2988977 1977-07-15
GB2988977 1977-07-15

Publications (2)

Publication Number Publication Date
EP0000635A1 true EP0000635A1 (fr) 1979-02-07
EP0000635B1 EP0000635B1 (fr) 1981-07-29

Family

ID=10298829

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19780300146 Expired EP0000635B1 (fr) 1977-07-15 1978-07-12 Lame à action brusque et sa méthode de fabrication

Country Status (2)

Country Link
EP (1) EP0000635B1 (fr)
DE (1) DE2860881D1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0015782A1 (fr) * 1979-03-13 1980-09-17 Ranco Incorporated Interrupteurs à action brusque
FR2620565A1 (fr) * 1987-09-15 1989-03-17 Bk Patent Dev Element mecanique bistable, dispositif le comportant, et procede et appareil pour sa fabrication
US5771169A (en) * 1996-08-29 1998-06-23 Case Corporation Site-specific harvest statistics analyzer
CN103187213A (zh) * 2011-12-29 2013-07-03 上海良信电器股份有限公司 热过载继电器的动作机构

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2805297A (en) * 1954-04-05 1957-09-03 Guardian Electric Mfg Co Snap switch mechanism
FR1142435A (fr) * 1955-06-07 1957-09-18 Interrupteur à action brusque
CH496311A (de) * 1970-03-25 1970-09-15 Adolf Feller Ag Fabrik Elek Sc Elektrischer Steuerschalter
DE2002659A1 (de) * 1970-01-22 1971-08-05 Siemens Ag Verfahren zur Herstellung von mit Kontaktauflagen versehenen Kontaktteilen
FR2291598A1 (fr) * 1974-11-16 1976-06-11 Ranco Inc Lames pour commutateur a action brusque

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2805297A (en) * 1954-04-05 1957-09-03 Guardian Electric Mfg Co Snap switch mechanism
FR1142435A (fr) * 1955-06-07 1957-09-18 Interrupteur à action brusque
DE2002659A1 (de) * 1970-01-22 1971-08-05 Siemens Ag Verfahren zur Herstellung von mit Kontaktauflagen versehenen Kontaktteilen
CH496311A (de) * 1970-03-25 1970-09-15 Adolf Feller Ag Fabrik Elek Sc Elektrischer Steuerschalter
FR2291598A1 (fr) * 1974-11-16 1976-06-11 Ranco Inc Lames pour commutateur a action brusque

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0015782A1 (fr) * 1979-03-13 1980-09-17 Ranco Incorporated Interrupteurs à action brusque
FR2620565A1 (fr) * 1987-09-15 1989-03-17 Bk Patent Dev Element mecanique bistable, dispositif le comportant, et procede et appareil pour sa fabrication
GB2210506A (en) * 1987-09-15 1989-06-07 Bk Patent Dev Snap action devices and methods and apparatus for making same
GB2210506B (en) * 1987-09-15 1991-11-06 Bk Patent Dev Methods and apparatus for making snap action devices
US5771169A (en) * 1996-08-29 1998-06-23 Case Corporation Site-specific harvest statistics analyzer
CN103187213A (zh) * 2011-12-29 2013-07-03 上海良信电器股份有限公司 热过载继电器的动作机构
CN103187213B (zh) * 2011-12-29 2015-03-25 上海良信电器股份有限公司 热过载继电器的动作机构

Also Published As

Publication number Publication date
DE2860881D1 (en) 1981-10-29
EP0000635B1 (fr) 1981-07-29

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