US3436502A - Electric pressure-control snap switch - Google Patents

Electric pressure-control snap switch Download PDF

Info

Publication number
US3436502A
US3436502A US613499A US61349967A US3436502A US 3436502 A US3436502 A US 3436502A US 613499 A US613499 A US 613499A US 61349967 A US61349967 A US 61349967A US 3436502 A US3436502 A US 3436502A
Authority
US
United States
Prior art keywords
spring
switch
control lever
torque
diaphragm
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
US613499A
Other languages
English (en)
Inventor
Ernst M Egli
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.)
Patinvest Patent und Investment AG
Original Assignee
Patinvest Patent und Investment AG
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
Priority claimed from DE1966P0026719 external-priority patent/DE1939186U/de
Application filed by Patinvest Patent und Investment AG filed Critical Patinvest Patent und Investment AG
Application granted granted Critical
Publication of US3436502A publication Critical patent/US3436502A/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
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/26—Details
    • H01H35/2607—Means for adjustment of "ON" or "OFF" operating pressure
    • H01H35/2614—Means for adjustment of "ON" or "OFF" operating pressure by varying the bias on the pressure sensitive element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/02—Details
    • H01H13/26—Snap-action arrangements depending upon deformation of elastic members
    • H01H13/28—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs
    • 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
    • H01H5/06—Energy stored by deformation of elastic members by compression or extension of coil springs

Definitions

  • the present invention relates to an electric snap-action switch for controlling the pressure of liquids or gases and especially suitable for being employed for a clothes washing or dish-washing machine or the like, wherein this switch is provided with at least one contact spring which projects between a pair of fixed switch contacts and the operation of which may be controlled by the movements of an element, for example, a diaphragm, which is subjected to the pressure of a liquid or gas and then acts upon an intermediate control lever which is connected to the contact spring by a snap spring and is also acted upon by an adjusting spring in a direction substantially opposite to the direction of movement of the element when subjected to an increasing pressure of the liquid or gas.
  • an element for example, a diaphragm
  • the position of the opposite change-over points or contacts of the switch are determined by the force of the adjusting spring acting upon the control lever in the direction opposite to the action of an element, for example, a diaphragm, which is connected to the control lever and is subjected to and movable under the changing pressure of a liquid or gas.
  • the distance between these change and re-change points is, however, dependent upon the distance between the fixed switch contacts and also upon the elasticity constant of the adjusting spring.
  • the minimum distance between these contacts is, in turn, dependent upon the admissible flashover or breakdown voltage of the switch, while the maximum distance is dependent upon the geometric properties of the switch and its housing.
  • the dimensions of the switch housing also determine the dimensions of the adjusting spring which, in turn, affect the elasticity constant and the adjustability of this spring. If, therefore, the contact spring should change over from one fixed contact to the other only when a relatively strong force is exerted upon the control lever by the element, for example, a diaphragm, which is acted upon by the pressure to be controlled e.g. by a relatively high liquid or gas pressure the necessary spring force of the adjusting spring can only be attained if this spring has such a high elasticity constant that it will produce an opposing or bracing force of sufficient strength. This, however, means that the minimum distance between the change and rechange points must also be relatively large.
  • this object is attained by providing the snap-action switch with an additional compensating spring, a force component of which also acts upon the control lever but in a direction different from the action of the adjusting spring and exerts a torque upon the control lever which extends in the opposite direction to the torque which is exerted upon this lever by the adjusting spring.
  • this compensating spring By the provision of this compensating spring a torque is produced and exerted upon the control lever which is superimposed on the torque which is produced by the adjusting spring. Due to the pivoting movement of the control lever, this additional torque at first increases in strength and, after the control lever is pivoted for a certain distance, its strength again decreases. The increase of this torque is caused by the increase in the length of the lever moment arm which is determined by the distance between the line connecting the bearing points of the compensating spring and the pivotal axis of the control lever, whereas the decrease of this torque is caused by the release of the compensating spring.
  • the superimposition of the two opposing torques one of which is produced by the adjusting spring and the other by the compensating spring, has the eflect that the resultant torque line at first ascends very steeply substantially in the direction of travel of the control lever and then slopes off to some extent after the control lever reaches a central area between the minimum change point and the maximum change point.
  • This means that within the area adjacent to the re-change point and also to the minimum change point only a small resultant torque will be required for producing a movement of the control lever. Within the area adjacent to the maximum change point, however, a greater torque will be required for producing the same movement of the control lever.
  • This operation which prior to this invention could only be attained by employing different snap switches or by exchanging the adjusting springs for others of a different strength, may now be attained in the same snap switch by one and the same spring system, and it only requires the initial tension of the same adjusting spring to be varied when the switch is to be used for controlling different pressures. It is, however, important that, regardless of the initial tension to which the adjusting spring might be adjusted, the switch will be designed so as to permit the lowest change point and the re-change point to be spaced at a short distance from each other and also to insure that the lowest change point and the highest change point will be separated by a sufficiently large distance.
  • the compensating spring according to the invention is preferably provided in the form of an omega ((2) leaf spring, one end of which is supported on a fixed or adjustable point of the switch, while its other end acts upon the control lever.
  • omega leaf spring it is however, also possible to employ a curved leaf spring of another shape or a coil compression spring or the like.
  • Another possibility of influencing the characteristic of the torques consists, according to the invention in providing a compensating spring which has a linear or progressive characteristic but preferably a negative or digressive characteristic.
  • a snap-action switch of the above-mentioned type is designed as a polyphase switch and provided with sever-a1 identical switch systems, and if the diaphragm therefore acts upon several control levers, the additional difliculty occurs that, when one of the control levers yields under the pressure which acts upon the diaphragm, the diaphragm will tilt at an angle.
  • the switch is provided with several similar switch systems which are controlled by a common diaphragm and each of which consists of a pair of fixed contacts, a contact spring, a control lever, a snap spring, and adjusting spring, and a compensating spring, the further great advantage is attained that the switch may be easily assembled and, if desired or necessary, its individual elements may also be easily exchanged for others of the same kind.
  • Another advantageous feature of the invention resides in providing the outer edge portion of one of the two parts of the switch housing with an inwardly projecting bead which, when the housing is being closed, slides elastically over and behind, the outwardly projecting edge of the other housing part so as to grip the latter securely. Because of this construction it is only necessary after the switch elements have been installed in the housing to press the two parts of the housing telescopically into each other so that the bead on the elastic edge portion of the one housing part will snap over the outwardly projecting edge portion of the other housing part and thereby grip the latter securely and seal the housing tightly.
  • FIGURE 1 shows a cross section of a single-pole switch according to the invention
  • FIGURE 2 shows a cross section of a polyphase switch according to the invention
  • FIGURE 3 is a diagrammatic illustration of the torques acting upon the control lever.
  • FIGURE 4 is a torque diagram showing the relation of the torques to the course of movement of the control lever.
  • the single-pole pressure-control switch according to the invention as illustrated in FIGURE 1 comprises a diaphragm 1 which is mounted peripherally within a housing 7 and may be acted upon by the pressure of a liquid or gas entering the lower part of the switch housing through an inlet fitting 2.
  • Diaphragm 1 carries a supporting plate 3 to which a central tappet 4 is secured; the tappet 4, in turn, acts upon a control lever 5 which is mounted at one end on housing 7 so as to be pivotable about this end in a vertical direction.
  • the control lever 5 is further associated with a contact spring 9 which is likewise secured at one end to housing 7 and provided with a longitudinal slot through which the control lever 5 may pivot from one side of contact spring 9 to the other.
  • the free other end of contact spring carries a contact 10 which is located between the two fixed switch contacts 11 and 12 with which it is alternately adapted to engage.
  • contact spring 9 is pivotably connected to one end of a snap spring 13 in the form of a barrel spring, the other end of which is likewise pivotably connected to the free end 14 of control lever 5 in such a manner that, as soon as the control lever is pivoted and passes the plane of contact spring 9, it snaps over to the other side, thereby pivoting the contact spring 9 in the opposite direction and thus reversing the switching position or mode of contact 10 relative to the fixed contacts '11 and 12.
  • control lever 5 is further provided with a downwardly-bent extension 15 which serves as an abutment for one end of a compensating spring 16 in the form of an omega leaf spring, the other end of which is supported on a fixed or vertically adjustable abutrnent 17.
  • control lever 5 in the upward direction is limited by a stop projection 18 on the upper wall of housing 7, while the downward stroke of control lever 5 is limited by the lowest position of the tappet 4, that is, the position in which at a decrease of pressure on the diaphragm 1, this diaphragm rests upon the upper edge of the annular flange 19 on the bottom wall of housing 7 around the opening of the inlet 2.
  • FIGURE 2 illustrates a polyphase pressure-control switch according to the invention, in which the components which are similar to those in FIGURE 1 are designated by the same reference numerals.
  • the three spring systems each of which also consists in this case of a control lever 20, a contact spring 9, a snap spring 13, and a compensating spring 16 are disposed laterally adjacent but in reverse positions to each other.
  • control lever which in this case is designated by the numeral 20 is bent downwardly from its fixed end so that its pivoting range lies outside of the pivoting range of contact spring 9.
  • Contact spring 9 therefore no longer needs to be slotted to permit the control lever 20 to pivot through the contact spring.
  • the pivoting range of control lever 20 is limited by two stop members which in this case are designated by the numerals 21 and 22.
  • FIGURE 3 is a diagrammatic illustration of the forces WhlCh act upon the control lever or levers 5 or 20.
  • the adjusting spring 6 exerts a pressure in the direction of the arrow J upon the control lever 5 or 20 which results in a positive torque M a-J in a counterclockwise d rection of the lever arm a which is determined by the distance between the pivot point of control lever 5 or 20 and the direction of pressure I of the adjusting spring 6 upon the control lever.
  • This lever arm b is determined by the distance between the direction of the force S from the pivot point of control lever 5 or 20.
  • control lever 5 or 20 is acted upon the compensating spring '16 which is braced on the points 14 and 17 and exerts a pressure in the direction of the arrow K which is determined by the line of connection between the points 14 and 17 and is spaced from the pivot point of control lever 5 or 20 by a lever arm 0.
  • a negative torque M c-K (in the clockwise direction) results; this torque is opposed to the torque which is produced and the joint action of the adjusting spring 6 and the snap spring 13.
  • FIGURE 4 further shows, at a certain distance from the line indicating the lower stop 22, the line 23 which indicates the re-change point and must be located at a higher level than the lower stop line 22 because a positive torque must still be prevalent at the re-change point 23 in order to insure a proper engagement between the adjusting spring 6 and control lever 5 or 20.
  • FIGURE 4 further shows two straight inclined dotted lines MJ and M which represent the path of the torque M a-l which is produced by the adjusting spring *6. These two straight lines M and M differ from each other by the fact that according to line M the adjusting spring 6 is given a higher initial tension and that this line is therefore shifted more to the right.
  • the left part of the diagram according to FIGURE 4 further indicates by a dot-and-dash line the torque curve M which results from the product of the force K of the compensating spring 16 multiplied by the lever arm as indicated in FIGURE 3.
  • This torque M has a negative value, and the force K of compensating spring 16 and thus also accordingly the torque M are of such a magnitude that the latter will be negative along the entire extent of travel of control lever or 20 and that the torque line will not intersect the vertical zero line except at points above and below the two stop lines 21 and 22, respectively.
  • the value of the torque M will at first increase since by the action of the upwardly moving diaphragm the control lever 5 or 20 will be pivoted in the clockwise direction which will result in a progressive increase of the length of the lever arm c and thus also in a corresponding increase of the torque M
  • the compensating spring 16 will be released and the spring force K will therefore be reduced to such an extent that even the further increase in the length of the lever arm c can no longer compensate this reduction of the spring force K.
  • the re-change point 23 is located within the torque line (M -I-M for example, at a pressure of 20 mm. W.G.
  • the lowest change point 24 may already occur at a pressure of 50 mm. W.G. so that the difference only amounts to 30 mm. W.G.
  • the adjusting spring 6 is then adjusted to have a higher tension, greater switching forces will be required which, in turn, require higher pressures which would then have to amount to, for example, mm. W.G., mm. W.G., and 200 mm. W.G.
  • the diaphragm 1 is provided with a thicker outer ring 26 which is clamped between the two opposite annular surfaces 27 and 28 of the upper housing part 7 and the lower housing part 29.
  • This lower housing part 29 which is preferably made of plastic has an outer rim 30 which encloses and projects upwardly from the outer ring 26 of diaphragm 1 and is slightly elastic. On its upper edge, it has an inwardly projecting bead 31 which, when the two-part switch housing is closed, snaps over the outer edge 32 of the upper housing part 7 and thus connects the two housing parts 7 and 29 tightly to each other.
  • the inner edge 33 of bead 31 is inwardly inclined in the manner as shown in FIGURES 1 and 2.
  • the tappets 4 on the diaphragm plate 3 project loosely through bores 34 which are provided in the control levers 20.
  • a three-point support of the control levers 20 on the diaphragm plate 3 is attained by providing not only a second, only partly indicated switch system behind the system which is completely shown in FIGURE 2 but also a third switch system which is located in front of the plane of the drawing.
  • each of the adjusting springs 6 of the three switch systems is supported at its upper end within a cap 8 which is screwed into the upper housing part 7 so as to permit it to be adjusted to different levels, it is possible to adjust the three adjusting springs 6 to different initial tensions which, in turn means that the forces which are exerted by the adjusting springs 6 so as to brace the diaphragm 1 will be of different strengths and that, as soon as a pressure is exerted upon the diaphragm 1, this pressure will overcome the force of that adjusting spring 6 which has the lowest initial tension.
  • An electric snap-action switch for controlling the pressure of liquids or gases, comprising a housing, a diaphragm peripherally and tightly secured to the outer wall of said housing and dividing the same into afirst part and a second part, said first housing part having an inlet opening through which the pressure to be controlled may enter said first housing part and act upon one side of said diaphragm so as to shift said diaphragm in the direction of said second housing part, at least one pair of fixed contacts mounted in said second part and spaced from each other, at least one contact spring having a fixed end mounted on said housing within said second part and a free end projecting between said fixed contacts and adapted to engage with one of said contacts when said pressure is below a certain value and With the other contact when said pressure increases above said value, at least one control lever having one end connected to said housing adjacent to the fixed end of said contact spring and pivotable at said fixed end relative to said contact spring, at least one tappet having one end secured to said diaphragm and another end engaging one side of said control lever, at least one
  • a compensating spring having a force component acting upon said lever in a direction different from the action of said adjusting spring and exerting a torque upon said lever extending in the opposite direction to said torque exerted thereon by said adjusting spring.
  • said compensating spring is a curved leaf spring one end of which is supported on a fixed part of said switch, while the other end of said curved leaf spring acts upon said control lever.
  • a switch as defined in laim 1 wherein said contact spring is provided with a longitudinal slot and said control lever is pivotable through said slot from one side of said contact spring to the other.
  • said housing consists of separate upper and lower parts, one of said housing parts having an outer edge portion with a bead thereon projecting in one direction, and the other housing part having an outer edge portion projecting in the opposite direction, said bead being adapted to snap elastically over the outer edge portion of said other housing part when said two housing parts are telescopically connected to each other.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Mechanical Operated Clutches (AREA)
  • Mechanical Control Devices (AREA)
US613499A 1966-02-08 1967-02-02 Electric pressure-control snap switch Expired - Lifetime US3436502A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP0038726 1966-02-08
DE1966P0026719 DE1939186U (de) 1966-02-15 1966-02-15 Schnappschalter, insbesondere fuer waschmaschinen od. dgl.

Publications (1)

Publication Number Publication Date
US3436502A true US3436502A (en) 1969-04-01

Family

ID=25990042

Family Applications (1)

Application Number Title Priority Date Filing Date
US613499A Expired - Lifetime US3436502A (en) 1966-02-08 1967-02-02 Electric pressure-control snap switch

Country Status (6)

Country Link
US (1) US3436502A (enrdf_load_stackoverflow)
AU (1) AU420643B2 (enrdf_load_stackoverflow)
CH (1) CH450522A (enrdf_load_stackoverflow)
DE (1) DE1665312B2 (enrdf_load_stackoverflow)
GB (1) GB1169431A (enrdf_load_stackoverflow)
SE (1) SE328930B (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3594521A (en) * 1968-06-18 1971-07-20 Patinvest Ag Electric snap switch with fluid-actuated toggle mechanism
US3707691A (en) * 1970-06-03 1972-12-26 Int Standard Electric Corp Electromagnetic flat-type relay
US3856998A (en) * 1973-06-01 1974-12-24 Burroughs Corp Keyboard switch assembly with improved operating means
US4032180A (en) * 1973-08-21 1977-06-28 Texas Instruments Incorporated Locking device for washing machine door
US5001317A (en) * 1989-06-30 1991-03-19 Louis D. Atkinson Fluid activated switch apparatus
EP0507002A3 (en) * 1991-04-02 1992-12-09 Huba Control Ag Pressure switch
EP0958777A1 (en) * 1998-05-22 1999-11-24 Fagor, S.Coop. Ltda. Water level regulator in a dishwaser
US6346681B1 (en) * 1995-09-28 2002-02-12 Ronald S. Joyce Pressure switch
US6740828B1 (en) 2003-08-08 2004-05-25 Claudio R. Dacal Arm and safety switch
ITTO20090624A1 (it) * 2009-08-07 2011-02-08 Illinois Tool Works Sensore di pressione per un elettrodomestico con funzione aggiuntiva di sicurezza

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7830603U1 (de) * 1978-10-13 1979-05-17 Elektromanufaktur Zangenstein Hanauer Gmbh & Co, 8471 Zangenstein Membrandose fuer druckwaechter
DE3826749C1 (enrdf_load_stackoverflow) * 1988-08-05 1989-11-02 Eugen 8000 Muenchen De Ehs
CN111599625B (zh) * 2020-05-15 2025-07-15 杭州鸿雁电器有限公司 一种具有行程放大功能的纤薄式开关

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636093A (en) * 1950-08-09 1953-04-21 Magnavox Co Pressure switch
US2813944A (en) * 1954-11-12 1957-11-19 Carter Parts Company Pressure switch
US2934618A (en) * 1955-07-11 1960-04-26 Controls Co Of America Fluid pressure responsive switch

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636093A (en) * 1950-08-09 1953-04-21 Magnavox Co Pressure switch
US2813944A (en) * 1954-11-12 1957-11-19 Carter Parts Company Pressure switch
US2934618A (en) * 1955-07-11 1960-04-26 Controls Co Of America Fluid pressure responsive switch

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3594521A (en) * 1968-06-18 1971-07-20 Patinvest Ag Electric snap switch with fluid-actuated toggle mechanism
US3707691A (en) * 1970-06-03 1972-12-26 Int Standard Electric Corp Electromagnetic flat-type relay
US3856998A (en) * 1973-06-01 1974-12-24 Burroughs Corp Keyboard switch assembly with improved operating means
US4032180A (en) * 1973-08-21 1977-06-28 Texas Instruments Incorporated Locking device for washing machine door
US5001317A (en) * 1989-06-30 1991-03-19 Louis D. Atkinson Fluid activated switch apparatus
EP0507002A3 (en) * 1991-04-02 1992-12-09 Huba Control Ag Pressure switch
US6346681B1 (en) * 1995-09-28 2002-02-12 Ronald S. Joyce Pressure switch
EP0958777A1 (en) * 1998-05-22 1999-11-24 Fagor, S.Coop. Ltda. Water level regulator in a dishwaser
US6740828B1 (en) 2003-08-08 2004-05-25 Claudio R. Dacal Arm and safety switch
ITTO20090624A1 (it) * 2009-08-07 2011-02-08 Illinois Tool Works Sensore di pressione per un elettrodomestico con funzione aggiuntiva di sicurezza
WO2011017585A1 (en) * 2009-08-07 2011-02-10 Illinois Tool Works Inc. Pressure sensor for an electric household appliance with additional security function
US8904875B2 (en) 2009-08-07 2014-12-09 Illinois Tool Works Inc. Pressure sensor for an electric household appliance with additional security function

Also Published As

Publication number Publication date
AU420643B2 (en) 1972-01-19
DE1665312B2 (de) 1975-11-06
AU4421368A (en) 1970-04-09
GB1169431A (en) 1969-11-05
DE1665312A1 (de) 1970-12-03
SE328930B (enrdf_load_stackoverflow) 1970-09-28
CH450522A (de) 1968-01-31

Similar Documents

Publication Publication Date Title
US3436502A (en) Electric pressure-control snap switch
EP0453121B1 (en) Thermostat having a movable backstop
US5089673A (en) Pressure operated electrical switching device with plural lever actuated microswitches
US3609270A (en) Electric reversing switch
US2927171A (en) Snap acting switch
US3890477A (en) Control device
US3735080A (en) Snap-action electric switch
US2556981A (en) Snap acting control switch
US4464551A (en) Electric circuit controlling device and method of operating same
US3352983A (en) Pressure switch and electrical switch therefor
US3735069A (en) Snap-action electric switch
US4559422A (en) Microswitch
US3359387A (en) Pressure switch
US3182149A (en) Pressure-operated control having means for adjusting the actuating pressures of a plurality of control switches
US3573410A (en) Snap action pressure sensitive switch with snap disc resiliently supported between legs of a terminal
US4403206A (en) Balanced switch for thermostats or the like
US4737604A (en) Three stage pressure switch
US2975251A (en) Pressure switch
US4346272A (en) Control device and method of operating
US2360723A (en) Electric switch
US2647189A (en) Thermally actuated electric switch
GB2112210A (en) Electrical snap-action switch
US3412223A (en) Pressure switch
US4346276A (en) Multiple pressure switch
US4052574A (en) Pressure switch with snap-toggle adjusting means