US2113494A - Snap action mechanism - Google Patents

Snap action mechanism Download PDF

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Publication number
US2113494A
US2113494A US46200A US4620035A US2113494A US 2113494 A US2113494 A US 2113494A US 46200 A US46200 A US 46200A US 4620035 A US4620035 A US 4620035A US 2113494 A US2113494 A US 2113494A
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Prior art keywords
operating member
resilient
contact
operating
pressure
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US46200A
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English (en)
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Richmond Thomas Guthrig
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Individual
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Individual
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/60—Means for producing 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

Definitions

  • This invention relates to snap action mechanism for operating electric switches, valves, or other devices.
  • One of the objects of the present invention is to provide a non-magnetic snap action mechanism for use with switches whereby very small differentials may be obtained.
  • Another object of this invention is to provide a non-magnetic snap action mechanism for electrical switches which will have a snap action in each direction and will permit of a very small gap being used between the contacts.
  • a further object of the invention is to provide a non-magneticsnap action mechanism for a thermostatically controlled gas valve.
  • Figure 1 is a sectional view showing the device applied to a thermostat.
  • FIG. 2 is a side view of Figure 1 also in secion.
  • Figure 3 is a plan of Figure 1 with the top portion removed.
  • Figure 4 is a detail on an enlarged scale.
  • FIG. 5 is a detail.
  • Figure 6 is a sectional view of a modification of 5 Figure 1.
  • Figure 7 is a sectional view of a further modification of Figure 1.
  • Figure 8 is a sectional view 01' the device applied to a tumbler switch.
  • Figure 9 is a sectional view of the device apcasing 2, but insulated therefrom by material [3,-
  • the other end of the operating member is provided with a contact I which engages with a fixed contact 8 mounted upon a suitable member 9 se- 5 cured to the body I by means of pillars ill, but insulated therefrom by suitable insulating means. This limits the movement in one direction.
  • the contact 8 is preferably made adjustable in the member 9 and when set in the correct position 0 is locked therein -by the lock nut II.
  • An adjustable stop l2, or the like, is provided upon the body I so as to limit the movement in the other direction and thus control the opening or gap between the contacts to any suitable amount. If 15 desired, the stop I2 may be mounted upon the operating member.
  • Another support I4 in which is situated a suitable screw or the like !5 having a cup or conical bearing I6 which may be jewelled if desired, or made of hardened steel or other suitable material.
  • the operating member 5 is drilled longitudinally slightly offset of said knife edge 6 and the bottom of the hole is pro- 25 vided with a similar cup or conical bearing I'I which may be hardened steel or other material and pressed into position.
  • a strut member l8 such as a.
  • the strut member instead of being resilient may be made stifi and resiliency to press the strut member against 40 the operating member may be supplied by making either the support 3 or M resilient, or both. Further, all the three parts may be resilient, if desired.
  • a spring member 20 having a Qepending tongue 2
  • the thermally sensitive member comprises a brass tube 25 securely fixed at one end to the casing 2 and at the other end to a rod 26 which is a sliding fit in said casing.
  • the rod 26 is connected rigidly to a stirrup member 21 which is provided with an adjusting screw 28 having a pointed end or tip 29 made of insulating material such, for
  • This tip 29 is arranged to press against the spring member 20 so that its depending tongue 2
  • spring member is arranged to magnify the movement of the means which applies the lateral force to the strut member. The energy to carry over the contact I is stored partly in the strut member I8 and partly in the spring member 20.
  • the pressure on the longitudinal strut member i8 may be varied, and thus the distance through which the pointed end 29 and the de pending tongue must move to apply the necessary lateral pressure to the said strut member to cause the snap action is altered whereby the differential of the thermostat may be controlled.
  • having a pointer thereon, is provided upon the adjusting screw 28 so as to adjust the temperature at which the contacts open.
  • a suitable scale or the like 32 is provided upon the top of the cover 33 which fits on to the casing 2 and encloses the instrument. Any other adjustable means may be provided-in any other suitable position, so as to adjust the temperature at which the contacts open.
  • may have projecting lugs on each side which may be bent down to make contact with the stop below the strut member, or the stop may be bifurcated to pass round the strut member. Also a suitable hole may be made in the arm, which may be enlarged for the purpose, if necessary, for the tongue member 20 to pass therethrough.
  • the lateral pressure to cause the snap action is applied directly to the operating member 5 by the spring member 20, which is arranged so that it presses upon the operating member 5 close up to the knife edge 6 and in this manner magnification is also obtained.
  • the pressure for actuating the operating member 5 may be applied jointly both to the operating member and to the strut member.
  • the spring 20 is arranged to press upon the strut member l8 near to its fixed bearing i6 and another spring member 35 is mounted upon the pillars I and is provided with an adjustable screw 31 which presses upon the end of the operating member having the knife edge 6.
  • the strut member I8 may be given a considerable pressure by any suitable means and the screw member 31 applying the lateral pressure to the operating member is adjusted and locked in position so that the operating member is just on the balance; thus, when a very slight pressure is applied to the strut member by the thermally sensitive member, the operating member flicks over at once.
  • a very slight pressure is applied to the strut member by the thermally sensitive member
  • the operating member flicks over at once.
  • the tumbler 40 of a tumbler switch is made to press up against the spring 20 so as to apply the lateral pressure to the operating member 5 and cause the contact 1 to flick over on to the stop I2 and break the circuit.
  • the strut member l8 and other parts are the same as previously described with reference to the other examples.
  • Suitable terminals are provided for connecting the contacts I and 8 to the current supply and the tumbler may be insulated from the spring 20 or the spring 20 may be insulated from the operating member 5. Directly the pressure is removed the contacts snap together and join the circuit.
  • the device is so arranged that the strut member l8 in the normal position when the contacts I and 8 are closed holds them together by giving a clockwise moment, as shown in the Figures, about the knife edge, but when the strut member has a lateral pressure applied thereto which causes an anti-clockwise moment about the knife edge the clockwise moment is overbalanced and the anti-clockwise moment immediately snaps over the operating member with the contact I thus opening the circuit. Directly the lateral pressure is removed the clockwise moment again operates and the operating member snaps back 'to the normal position, closing the contacts automatically.
  • the configuration of the parts is such that the longitudinal pressure exerted by the said resilient means acting upon the strut and operating members is always in a direction on the same side of the pivot point in both extreme positions of the operating member and thus the moment about the pivot point is always in the same direction.
  • the parts In order to obtain the snap action the parts must be so arranged that when the pressure applied to the strut member increases beyond a certain amount the equilibrium of the system is instantaneously upset, and the snap action takes place.
  • the energy which causes the snap action to take place is stored in the resilient means exerting the longitudinal pressure or the resilient means applying the lateral pressure or both.
  • the strut member instead of being made of a-simple straight wire which, under pressure, deforms into a bow, may be a compound member which, when given a longitudinal pressure, will deform symmetrically so as to apply the pressure to the operating member.
  • the strut member deforms symmetrically, it is necessary that the point of application of its pressure to the operating member be always offset, otherwise the mechanism will not automatically return to the normal position.
  • a small movement of the member applying the lateral pressure creates a large movement at the end of the pivotal member, thus giving a large magnification.
  • any other means may be employed to apply a pressure such as a sensitive member controlled by pressure, or other hand operated means. If desired, this spring member having the depending tongue may be dispensed with and the thermally sensitive or other member may apply its force direct to said resilient strut member.
  • the mechanism, according to the invention is very suitable for this purpose and can be made to fulfil the requirements by arranging that the moment, which is applied to the operating member and which is overbalanced by the lateral applied force, reverses its sign on the trip action taking place, and therefore the operating member remains in its tripped position and does not return to the normal or reset itself.
  • the strut member l8 and the operating member are so arranged that when the trip action takes place, they move from one position past thedead centre to another position, and carry the contact 1 against the stop 45.
  • the moment created by the thrust of the strut member l8 reverses its sign when the operating. member has moved from one limiting position to the other.
  • the stop 5 is mounted upon the end of the resetting lever Mi, which is pivoted at 41.
  • the lever 46 is depressed to reset the operating member and close the contact, if conditions allow, so that they may be in a position to trip again when required.
  • a thermal device incorporating the above switch mechanism may be arranged to switch out the heating current should the kettle boil dry or no water he init, and the mechanism will not then automatically switch on until pressure is applied by hand to the resetting lever 46 to reset the operating member to the tripping position, which operation can only be carried out when the thermal element has cooled sufficiently.
  • the trip action mechanism may also be applied, for instance, to give an indication or an alarm when a certain temperature is reached, either by a rising or'by a falling temperature.
  • the trip action moves the operating member to join the contacts and makes the circuit, thus causing the indication or alarm to be given when the temperature reaches the predetermined amount.
  • the contacts remain together and the circuit closed until hand operated means are used to push the operating member back to its untripped position.
  • the thermally sensitive member in both cases trips the mechanism on reaching a predetermined temperature and the switch does not come back to the normal position unless reset by hand.
  • the operating member may have two or more contacts for double or multiple pole working mounted thereon, in which case it may take the form somewhat of a U, and the resilient means would then be situated between the two arms of the U.
  • acontact on each side of the operating member may be provided, if desired, so that in both extreme positions electrical contact is made or broken.
  • the movement may be limited in the position when the contacts are open by the operating member itself coming in contact with the strut member in the case in which the strut member is contained within a hole or slot in said operating member.
  • Suitable means are provided where necessary, for insulating the various members, and suitable terminals are provided for connecting to leads.
  • the pivot point of the operating member is provided with a knife edge to reduce friction and make it very sensitive, and this also applies to the anti-friction bearing of the strut member.
  • the snap action mechanism may be employed for other purposes than thermostats and may be used for operating switches, and further, that they may be applied to oher devices than switches, such as gas valves used in connection with thermostats, or in other devices in which a small movement is required to be magnified to give a large movement of the operating member with snap action for actuating the desired mechanism, and can thus be applied to any devices for which it is suitable.
  • a snap action make and break mechanism comprising in combination a body, a non-resilient operating member pivoted at one end to said body, a member at the other end of said body, with which the other end of said operating member makes contact, a member pivotally supported at one end on said body and at the other end on said operating member applying a resilient turning moment to said operating member in one direction, means for applying a resilient force to said operating member to create a turning moment in the opposite direction, movement of said operating member taking place when one turning moment overbalances the other turning moment, the snap action being due to the overbalanced turning moment decreasing more rapidly than the other turning moment, and means to prevent said operating member passing through the dead centre or neutral position.
  • a snap action make and break short gap mechanism comprising in combination, a body, two upstanding supports on said body, a nonresilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a member on said body, a member on said operating member contacting with said body member, means for preventing said operating member passing through dead centre or neutral position when the contacting members are opened, a resilient member mounted upon said body and pressing upon said operating member applying a turning moment in the opposite direction, and means coacting with said resilient member to apply pres-. sure thereto.
  • a snap action make and break short gap switch comprising in combination a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a. resilient turning moment in one direction, a contact on said body, a contact on said operating member engaging with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, resilient means mounted upon said body for applying a turning moment to said operating member in the opposite direction, and means coacting with said resilient member to apply pressure thereto.
  • a snap action make and break short gap thermostatic switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a contact on said body, a contact on said operating member engaging with said body contact,
  • a snap action make and break mechanism comprising in combination a body, an operating member pivoted at one end to said body, a member at the other end of said body, with which the other end of said operating member makes con tact, a member pivotally supported at one end on said body and at the other end on said operating member applying a resilient turning moment to said operating member in one direction, and a resilient member mounted upon said body adapted to apply a force which creates a turning moment which is applied in the opposite direction to said operating member, movement of said operating member taking place when one turning moment overbalances the other turning moment,
  • a snapaction make and break short gap mechanism comprising in combination, a body, two upstanding supports on said body, an operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a member on said body, a member on said operating member contacting with said body member, a resilient member mounted upon said body adapted to apply a force which creates a turning moment which is applied in the opposite direction to said operating member, and means coacting with said resilient member to apply pressure thereto, said snap action taking place before the said operating member reaches the dead centre or neutral position.
  • a snap action make and break short gap switch comprising in combination a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a'resilient turning moment in one direction to said operating member, means for adjusting the end pressure on said floating member, a contact on said body, a contact on said operating member engaging with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon said body and pressing upon said operating member applying a turning moment in the opposite direction, and
  • a snap action make and break short gap thermostat comprising abody, two upturned supports provided upon said body, a non-resilient operating member, two pivoting means provided upon said operating member, one of said pivoted means engaging one of said supports, a floating member engaging between said other pivotal means and said other support for keeping said operating member in engagement with said support and applying a turning moment in one direction, a contact upon said body, a contact upon said operating member coacting with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon said body and pressing upon said operating member, a second resilient member mounted upon said body and pressing upon said floating member forapplying a turning moment in the opposite direction and a thermally sensitive member coacting with said second resilient member to apply pressure thereto.
  • a snap action make and break short gap switch comprising in combination a body, two
  • a snap action make and break short gap switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a contact on said body, a contact on said operating member engaging with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon said body, and pressing upon said floating member and means applying a turning moment in the opposite direction coacting with said resilient member to applypressure thereto.
  • a snap action make and break short gap switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a contact on said body, a contact on said operating member engaging with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon said body and pressing upon said floating member, and manually operated means coacting with said resilient member to apply pressure thereto.
  • a snap action make and break short gap thermostatic switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally sup- 2 ported at one end on one of said supports, a
  • a snap action make and break short gap switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally supported at one end on one of said supports, a floating member pivotally. supported upon said operating member and said other support applying a resilient turning moment in one direction, means for adjusting the end pressure on said floating member, a contact on said body, a contact on said operating member engaging with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon said body and pressing upon said floating member, and means applying a turning moment in the opposite direction coacting with said resilient member to apply pressure thereto.
  • a snap action make and break short gap thermostat comprising a body, two upturned supports provided upon said body, a non-resilient operating member, two pivoting means provided upon said operating member, one of said pivoted means engaging one of said supports, a floating member engaging between said other pivotal means and said other support for keeping said operating member in engagement with said support and applying a turning moment in one direction, means for adjusting the end pressure on said floating member, a contact on said body, a contact upon said operating member coacting with said body contact, means for preventing said operating member passing through dead centre or neutral position when the contacts are opened, a resilient member mounted upon.
  • a snap action make and break short gap switch comprising in combination, a body, twoupstanding supports on said body, a V groove in one support, a cup shaped bearing in the other said support, a non-resilient operating member, aknife edge on said operating member engaging said V groove on said support, a cup shaped bearing on said operating member, a floating member supported in said cup bearings on the support and operating member respectively, said floating member applying a resilient turning moment in one direction to said operating member, means for adjusting the force exerted by said-floating member upon said operating member, a contact on a portion of said operating member remote from the two bearings, a contact on said body adapted to be engaged by said contact on said operating member, a stop to limit the gap between the contacts and to prevent the operating member from passing through dead centre or neutral position, a resilient member mounted upon said body to press upon said operating member for applying a turning moment in the opposite direction, and means coacting with said resilient member to apply pressure thereto.
  • a snap action make and break short gap switch comprising in combination,-a body, two upstanding supports on said body, a V groove in one support, a cup shaped bearing in the other said support, a non-resilient operating member, a knife edge on said operating member engaging said V groove on said support, a cup shaped bearing on said operating member, a floating member supported in said cup bearings on the support and operating member respectively, said floating member applying a resilient turning moment in one direction to said operating member, means for adjusting the force exerted by said floating member upon said operating member, a contact on a portion of said operating member remote from the two bearings, a contact on said body adapted to be engaged by said contact on said operating member, a stop to limit the gap between the contacts and to prevent the operating member from passing through dead centre or neutral position, a resilient member mounted upon said body to press upon 'said floating member for applying a turning moment in the opposite direction, and means coacting with said resilient member to apply pressure thereto.
  • a snap action make and break short gap thermostatic switch comprising in combination, a body, two upstanding supports on said body, a non-resilient operating member pivotally supported atone end on one of said supports, a floating member pivotally supported upon said operating member and said other support applying a resilient turning moment in one direction, a contact on said body, a contact on said operating member engaging with said body contact,

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  • Mechanisms For Operating Contacts (AREA)
  • Thermally Actuated Switches (AREA)
US46200A 1935-07-26 1935-10-22 Snap action mechanism Expired - Lifetime US2113494A (en)

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Application Number Priority Date Filing Date Title
GB2113494X 1935-07-26

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US2113494A true US2113494A (en) 1938-04-05

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US46200A Expired - Lifetime US2113494A (en) 1935-07-26 1935-10-22 Snap action mechanism

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US (1) US2113494A (en(2012))
BE (1) BE415342A (en(2012))
DE (1) DE685451C (en(2012))
FR (1) FR803737A (en(2012))
NL (1) NL43778C (en(2012))

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3045085A (en) * 1958-08-28 1962-07-17 American Thermostat Corp Probe type thermostat
US20060207986A1 (en) * 2005-03-16 2006-09-21 Anthony Brown Multi-function liquid container

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE549281A (en(2012)) * 1956-04-30

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3045085A (en) * 1958-08-28 1962-07-17 American Thermostat Corp Probe type thermostat
US20060207986A1 (en) * 2005-03-16 2006-09-21 Anthony Brown Multi-function liquid container
US7706671B2 (en) * 2005-03-16 2010-04-27 B2M Asset Management, Llc Multi-function liquid container

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Publication number Publication date
NL43778C (en(2012))
FR803737A (fr) 1936-10-07
BE415342A (en(2012))
DE685451C (de) 1939-12-18

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