US3786212A - Condition responsive control device with capacity for independent adjustment of control points - Google Patents

Condition responsive control device with capacity for independent adjustment of control points Download PDF

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Publication number
US3786212A
US3786212A US00236732A US3786212DA US3786212A US 3786212 A US3786212 A US 3786212A US 00236732 A US00236732 A US 00236732A US 3786212D A US3786212D A US 3786212DA US 3786212 A US3786212 A US 3786212A
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balance
control device
axis
housing
sensing
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US00236732A
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E Weber
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    • 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
    • H01H35/2657—Details with different switches operated at substantially different pressures
    • H01H35/2664—Details with different switches operated at substantially different pressures making use of a balance plate pivoting about different axes

Definitions

  • This invention relates to a control device, and, in par ticular, a control device in the form of a pressure switch.
  • the device includes an expansible chamber having a pressure sensitive element, such as a diaphragm, displaceable by variations in pressure.
  • the pressure sensitive element actuates a control means, such as a microswitch, to produce a control signal in response to the pressure variation.
  • the pressure sensitive element is coupled to a balance means which in turn, is coupled to a pair of biasing means or springs which urge the balance means in a direction opposing expansion of the chamber.
  • the resulting diaphragm displacement is transmitted to the balance means, causing the balance means to move against the force of the weaker spring.
  • This movement is a pivotal movement about a first stop or abutment located opposite the weaker spring.
  • the balance means is held against this stop by the heavier spring.
  • the pivotal movement continues until the moving portion of the balance means adjacent the weaker spring engages a second stop. At this point, the balance means is at the midpoint of its overall movement, further movement about the first stop being prevented by the second stop.
  • the balance means beings to pivot about the second stop until it reaches its extreme high pressure position.
  • the balance means will, of course, again pivot about the second stop, under the bias of the heavier spring, but in the opposite rotational direction until the middle position is again reached.
  • the balance means is restrained by the first stop from further pivotal movement about the second stop.
  • the balance means will again pivot about the first stop under the bias of the weaker spring. This movement continues until the balance means reaches its extreme low pressure position.
  • alternating fulcrum movement and alternating fulcrum apparatus The type of movement described above, and apparatus for effecting the same, will hereinafter be referred to as alternating fulcrum movement and alternating fulcrum apparatus.
  • an alternating fulcrum device is ideal in this context for the movement of the balance means about one of the alternating fulcrums can control the on actuation ahd the movement about the other other fulcrum can control the off deactuation.
  • the biasing means can be made adjustable to control the movement of the balance means and to concomitantly control the pressure values at which the switch is actuated or deactuated. Therefore, the use of an alternating fulcrum device having adjustable biasing means coupled to a balance means allows independent adjustment of the switch on and off points to practically any value in the overall operating range of the switch.
  • a pressure switch While the type of device contemplated has been and will be referred to as a pressure switch, it will be understood that the present invention can be equally well aapted to a vacuum responsive device, a temperature responsive device using a confined fluid, or a differential pressure responsive device.
  • US. Pat. No. 2,766,349 to Hamburg also discloses an alternating fulcrum pressure switch.
  • An important drawback here is that the springs of different strengths are not adjustable and thus independent adjustment of different settings is not possible. While it appears that, in an indirect manner, the biasing forces may be made to act through the pivot points of the balance means, the forces are transmitted through mechanical means which clearly will introduce substantial friction, and thus extraneous forces will also be a problem here. Also, in Hamburg, it is necessary to use two microswitches, one at each end of the balance means, to obtain a substantial differential between actuation points.
  • U.S. Pat. No. 3,210,486 to Holzer discloses an alternating fulcrum device, or more precisely, an alternating axis device. The arrangement is such that the biasing forces do not act on the axes at all times.
  • Another object is the provision of a connection and- /or linkage means between the balance means and the microswitch or control means, which linkage and/or connection means is simple, reliable and economical and which comprises relatively few parts.
  • a further object of the invention is the provision of a simple, inexpensive lost motion means between the balance means and microswitch or control means to compensate for different ranges of displacement of the balance means and of the actuator of the control means.
  • Another object is the provision of an alternating axis device wherein the axes nearly intersect at a pivotal set of stops, the effective connection point of the balance means to the control means being at a point on the balance means whereby the control means is not influenced by minute displacements of the balance means at the pivotal set of stops.
  • Yet another object is the provision of a control device having a piston and a diaphragm which are interconnected, and a means associated with the diaphragm for eliminating friction betwen the piston and its associated cylinder.
  • the present invention overcomes the difficulties found in the prior art devices by providing an adjustable biasing means whose lines of force act directly through each fulcrum or axis of the balance means. In one embodiment, this is accomplished by providing a balance means in the form of a beam with recessed portions at each end. Each recess provides additional surfaces on the balance means whereby the stop means and biasing means may be aligned with each other.
  • the balance means takes the form of a plate which pivots about two alternating axes, each axis being defined by stops which are spaced from each other.
  • Compression springs have the advantage that they can be most readily positioned on the side of the balance plate opposite to the pressure sensing means and associated pressure inlet. Clearly, in most circumstances access to the switch will be easier from the side opposite the inlet. Thus, with compression springs, adjustments to the spring forces (and thus the response characteristics of the switch) can be made from the side opposite to the inlet. Also, when tension springs are used, mechanisms to permit rotation of the adjustment screws with respect to their associated springs are required. With the use of compression srings, no such mechanisms are required, since the springs themselves are free to rotate. The use of coil springs in cpmpression is made more practical by the addition of special spring guides to prevent buckling.
  • Another important feature of the present invention is the fact that the structural arrangement enables the use of a single, interchangeable, sensitive microswitch to obtain a large scale independent adjustment of control points.
  • an alternating fulcrum movement can be used in conjunction with the inherent differential between distinct actuator control positions (e.g., on, off positions) of a conventional, sensitive microswitch to obtain widely and independently variable control points in terms of pressure.
  • the almost microscopic fixed differential inherent in the microswitch is effectively made adjustable over a very large range by the mechanism of the present invention. This is accomplished by providing a single actuator, such as a push button, extending from the microswitch casing and operatively connected to the balance means at a point between the two sets of stops exclusive of the pivotal set.
  • a single actuator such as a push button
  • the above-described combination of a single microswitch, having a single actuating button with an alternating fulcrum device is facilitated by interposing a resilient means between the balance plate and the microswitch.
  • the microswitch actuating button displacement will be very small when compared with the displacement of the pressure sensitive element or balance means.
  • the resilient means is made sufficiently weak as to absorb some of the movement of the balance means during its normal stroke.
  • the resilient means provides an extremely simple, inexpensive lost motion connection between the balance means and the control means which is particularly suitable for use with the present type of alternating fulcrum device. Any resilient means is subject to wear and this wear would normally change the response characteristics of the pressure switch. However, in an alternating fulcrum device, where on and off points are independently adjustable, any change in response characteristics can readily be compensated.
  • the fact that the actuating means is effectively connected to the balance plate between the two sets of stops exclusive of the pivotal set prevents any substantial multiplication of vertical movement due to minute displacements of the balance plate at the pivot.
  • FIG. 1 is a view, partly in side elevation and partly in section, of a device according to one embodiment of the invention.
  • FIG. 2 is an exploded perspective view of most of the elements of the device of FIG. 1, certain elements being shown in section.
  • FIG. 3 is another exploded perspective view of the device of FIG. 1 including elements not shown in FIG. 2.
  • FIGS. 4, 5 and 6 are fragmentary sectional views of the device shown in FIG. 1, these figures illustrating various displaceable elements at different positions.
  • FIG. 7 is a fragmentary exploded perspective view of a modification to the embodiment of FIG. 1.
  • FIG. 8 is a fragmentary sectional view of a modification to the embodiment of FIG. 1.
  • FIG. 9 is a view partly in section and partly in side elevation of a device according to another embodiment of the invention.
  • FIGS. 1-6 in the specifically illustrated embodiment of the invention, therexis shown a cylindrical housing 1 having a bottom end wall member 2 forming one wall of a sensing chamber 4. Another wall of the sensing chamber 4 is defined by a pressure sensing element herein illustrated as a diaphragm 6.
  • the diaphragm in effect divides the housing into two chambers, namely, aforementioned lower sensing chamber 4, and upper control chamber 5.
  • the periphery of the diaphragm is held in place, on one side, by a cylinder ring 8 secured to the housing 1 and, on the other side, by an O-ring 10 which is pressed against the diaphragm by the bottom end wall member 2.
  • the member 2 in turn, is held in place in the housing by a snap ring 12.
  • pressure sensing means illustrated here takes the form of a diaphragm, any other suitable means such as a bellows or piston may be used.
  • connection means 14 threaded to accommodate an appropriate conduit or fitting, communicates with a central passage 16 in the bottom end wall member 2.
  • the central passage 16 in turn, communicates with the sensing chamber 4.
  • the upper surface of the diaphragm 6 engages a piston 18 which moves within the cylinder ring 8. Abutment l5 prevents the piston from falling out of its cylinder and functions as a lower limit to downward movement.
  • the piston 18 is centered in the diaphragm by an annular convolution 20 on the diaphragm formed by pressure when the device is in operation.
  • the convolution 20 has a mean diameter slightly greater than the diameter of the piston and is shaped by pressure so as to engage the peripheral edge portions of the piston to prevent lateral movement thereof.
  • the housing includes an intermediate wall portion 22 which serves as an upper abutment to secure the cylinder 8 in place within the housing 1.
  • a bore 24 passing therethrough and having a counterbore 25 at the upper surface of the wall 22.
  • a pin 26 stepped in two diameters is disposed in the bore, larger diameter portion 27 being disposed within the counterbore 25.
  • a recess 28 which carries a ball 29.
  • the ball 29 defines a pivot about which the piston is free to rotate, and this freedom of rotation facilitates formation of the convolution 20 by pressure.
  • a shim 30 of spring-likg material Adjacent the upper surface of the intermediate wall 22 there is disposed a shim 30 of spring-likg material having a symmetrical spider-like shape.
  • the shim includes an annular outerrim 31, symmetrically arranged spokes 32 and a perforated inner hub 33.
  • the outer rim 31 of the shim 30 is held in place against the intermediate wall portion 22 by a lower space member 38, but the inner hub 33 is free to move vertically along with the pin due to the resiliency of the shim material and the reduced resistance resulting from the spoked configuration.
  • Perforated hub 33 is suitably and firmly attached to a recessed portion 45 of a balance plate 42, located above the shim.
  • the balance plate 42 has a generally disc-like configuration with a lower surface 43 and an upper surface 44.
  • the recess 45 has a central ball receiving part with a lower concave portion 34 and an upper convex portion 35.
  • the lower concave portion engages the ball 29 of pin 26.
  • At points on the balance plate radially spaced from each other and near the periphery thereof are located three balls or spherical members 46, 47 and 48. Balls 46 and 47 are smaller than ball 48. Ball 46 protrudes downwardly from the balance plate, and ball 47 protrudes upwardly.
  • the balls are so located with respect to each other as to form the points of an equilateral triangle.
  • the balls may be secured within holes in the balance plate by staking or, alternatively, may be formed integrally with the balance plate.
  • the open spaces between the spokes 32 of the shim 30 are aligned with the three balls so as to permit a direct contact thereof with the intermediate wall.
  • a ball stop plate 50 held in place by lower spacer member 38.
  • a pair of coil springs 52,53 which are connected at their lowermost ends to spring rests 54,55.
  • the spring rests include annular shoulders 56,57 and downwardly projecting fingers 58,59 at the lower portions thereof. These fingers 58, 59 engage complementary depressions 60,61 in the balance plate to bias the plate downwardly.
  • the three balls 46, 47, 48 are arranged on the balance plate so as to define a pair of axes A,B (see FIG. 2) about which the balance plate alternately pivots.
  • Each axis is defined by two points, each point being a point of engagement of one ball with an adjacent sur face.
  • the balls are arranged so that the largest ball 48 i is common to both axes, locating one of the two points defining each axis. Ball 48 and the adjacent surfaces engaged thereby are referred to as the pivotal set of stop means.
  • the ball stop plate 50 includes a central opening with curved cut out portions 62,63 for allowing the passage of the spring rests 54,55 therethrough.
  • the sectional view of FIG. 1 is taken through these portions 62,63 so that the largest open area of the plate 50 is illustrated.
  • the orientation of the balance plate 42 with respect to the ball stop plate 50 is such that the balls 46,47 and 48 are not aligned with the cut out portions 62 and 63.
  • ball 47 will come into contact with the ball stop plate 50 upon an upward pivoting movement of the balance plate 42.
  • the largest ball 48 is of sufficient diameter to prevent any significant vertical movement thereof between the ball stop plate 50 and the intermediate wall 22.
  • the upper portion of the housing includes a top closure 66 having a pair of threaded openings 68,69 therein.
  • a pair of threaded adjustment screws 70,71 cooperate with these openings and with the coil springs 52,53 for adjusting the compression thereof.
  • the adjustment screws each include a tool engaging means 72,73 whereby each screw can be rotated to vary the vertical position thereof to adjust the associated spring.
  • Each adjustment screw includes a recess 74,75 at the bottom thereof, each recess receiving the uppermost portion of one of the coil springs 52,53.
  • Each of the two adjustment screws includes an annular rim portion 76,77, one rim portion 77 being at the uppermost end of its respective adjustment screw 71, the other rim portion 76 being located below the uppermost portion of its adjustment screw 70.
  • the spacing between the two adjustment screws 70,71 is such that the rim portions of each are mutually overlapping, the rim portion 77 being above the rim portion 76.
  • control means 78 Secured above the top closure 66 is a control means 78, preferably in the form of an electric, single pole, double throw, low differential, low force, two-position spring-return microswitch.
  • Any suitable electrical switch or fluid controlling valve of the spring-return or toggle type could be used equally well, as long as there are provided two distinct actuation positions separated by a displacement differential, the positions corresponding to two distinct mutually cancelling control modes.
  • these two positions and their respective control modes are referred to herein as the actuation or on position and the deactuation or off positions.
  • the microswitch here includes a casing. 79 from which extends an actuating button 82, having one position at which the switch is actuated (i.e., the on position) and another, different position at which the switch is deactuated (i.e., the off position), so that an inherent displacement differential exists between the on and off positions.
  • the microswitch is fastened to the housing 1 by an adjustable mount which can be used to vary the vertical position of the microswitch with respect to the housing 1.
  • an actuating post 84 between the actuating button 82 and the balance plate 42 transmits only the linear vertical displacements of the balance means to the actuating button.
  • a resilient means 86 is also interposed between the actuating button and the balance plate. This resilient means will be referred to as the amplification spring.
  • the amplification spring 86 is attached to the upper surface 44 of the balance plate 42 and is connected to the lower portion of the actuating post 84.
  • the amplification spring 86 is made sufficiently weak so as to serve as a lost motion connecting means, reducing the amount of motion transmitted from the balance plate 42 to the actuation button 82 during the normal stroke of the balance plate and diaphragm. This reduction of transmitted balance plate motion can be said to amplify the relative inherent displacement differential of the microswitch.
  • the piston moves through a stroke of approximately 0.006 inches.
  • the range of the microswitch button between on and off points is about 0.0005 inches to 0.0015 inches.
  • the amplification spring provides a simple and inexpensive means to compensate for these differences in displacement ranges.
  • the effective point of connection of the actuating post 84 to the balance plate is located approximately midway on a straight line between the two balls 46 and 47.
  • the actuating post 84 first connects with the amplification spring which, in turn, is connected with the balance plate 42
  • the post 84 may alternatively be directly attached to the balance plate (assuming the amplification spring has a different location).
  • the effective point of connection of the actuating post 84 with the balance means is the point at which the post 84 would engage the balance means if extended downwardly past the amplification spring. It is desirable to place the effective point of connection as close as possible to the midpoint of the line between balls 46 and 47.
  • the aforesaid line between the balls 46 and 47 can be considered as a third axis (in addition to axes A and B) about which the balance plate pivots during minute displacements of the balance means at ball 48.
  • Both guide members 90,91 and the ball stop plate 50 are secured in place between an upper spacer 92 and the aforementioned lower spacer 38.
  • the ends of the guide members can rotate inside of elongated cavities formed by recesses 117 and 118 in the upper spacer and the top surface of the intermediate wall 22.
  • the guides may be fastened to the stationary housing by means of suitable flexible members.
  • a transparent plastic cover 94 is attached to the top closure 66 to completely enclose the microswitch 78 and adjustment screws 70 and 71 to protect the same from dirt, dust or any other harmful materials in the surrounding environment.
  • Opening 95 through the housing 1 and upper spacer 92 together with an opening 119 in the top closure 66 serves the purpose of providing a passage for the necessary connecting cables. Opening 95 is suitably threaded for connection with a conduit.
  • FIGS. 1-3 The operation of the device illustrated in FIGS. 1-3 will be described below, with reference being made to FIGS. 4, 5 and 6 showing various displaceable elements in different sequential positions.
  • FIG. 4 illustrates the extreme low pressure position of the diaphragm and balance plate.
  • the balls 46 and 48 are held at rest against the intermediate wall 22 by the force of the coil springs 52,53.
  • Ball 47 is at an intermediate position and piston 18 rests on abutment 15.
  • the ball 29 transmits the motion of the pin 26 past the inner hub 33 of the flexible shim 30 and to the concave portion 34 of the balance plate 42.
  • the balance plate will first begin to move against the force of the weaker of the two coil springs, namely, spring 53, lifting ball 47.
  • the above described movement of the balance plate therefore, is a counterclockwise pivotal movement about axis A (defined by the points of contact of balls 46 and 48 with the intermediate wall 22).
  • Pivotal movement of the balance plate about the axis A will continue until the upper surface of the ball 47 comes into contact with the ball stop plate 50 to restrain further upward movement. At this point the balance plate is disposed in the middle position as illustrated in FIG. 5. The balance plate will remain in this position until the pressure in the chamber 4 has increased to an amount sufficient to overcome the bias of the high pressure spring 52. At this point, the ball 46 is lifted from the intermediate wall and moves upwardly. To permit such movement, the balance plate pivots in a clockwise direction about the axis B (defined by the points of contact of balls 47 and 48 with the ball stop plate 50). Pivotal movement of the balance plate about axis B will continue until the extreme high pressure position shown in FIG. 6 is reached.
  • the above described alternate pivotal movements of the balance plate effect only a linear displacement of the actuating post 84.
  • the motion is transmitted from the balance plate to the actuating post 84 via the amplification spring 86 which serves as a lost motion connection.
  • the linear movement of the actuating post is transmitted to the actuating button 82 of the microswitch 78 for actuation and deactuation thereof.
  • the vertical position of the microswitch 78 with respect to the housing 1 is adjusted so that the middle position of the balance means, as illustrated in FIG. 5, corresponds to the middle position in the inherent displacement differential of the microswitch.
  • the microswitch actuating button is midway between the actuation and deactuation points.
  • the deactuation or off point of the microswitch corresponds to the vertically lower actuation button position in relation to the on point.
  • the balance plate 42 pivots about the axis A until reaching the middle position. With sufficient additional increase in pressure, the balance plate then begins to pivot about axis B. During this latter pivotal movement, the post 84 will cause the button 82 to pass through the actuating position moving the switch to the on position.
  • a pressure decrease causes the balance plate to move back to the middle position by pivoting about axis B. Then, after sufficient decrease in pressure, the balance plate begins to pivot about axis A toward the low pressure position. During this latter pivotal movement about axis A, post 84 causes the button 82 to pass through the deactuation point moving the switch to the off position.
  • the values of pressure at which the microswitch is moved into the on and off positions are determined by the adjustments to the biasing forces of the springs 52,53.
  • the high pressure spring 52 is adjusted to exert a very high biasing force. This is accomplished by moving the adjusting screw 70 to a relatively low position.
  • the low pressure spring 53 is adjusted to exert a relatively weak biasing force by moving the adjusting screw 71 to a relatively high position.
  • the balance plate and switch button again return to their middle positions but the microswitch remains in the on condition.
  • the balance plate After a large pressure drop to a point near the minimum pressure, the balance plate begins to pivot from its intermediate position toward its low pressure position for deactuating the microswitch to the off condition.
  • FIG. 7 shows an alternative embodiment wherein the ball stops, rather than being secured to the balance plate, are located separately therefrom.
  • the complete stop means included the combination of the three balls on the balance plate, plus the lower, intermediate wall 22, plus the upper, ball stop plate 50; the complete stop means in the present embodiment includes the balance plate itself plus a set of balls adjacent both the upper and lower faces of the balance plate.
  • movement of the balance means caused the balls thereon to alternately come into contact with the intermediate wall and ball stop plate, in the arrangement of FIG. 7, the balance plate itself comes into contact with stationary balls disposed on either side thereof.
  • elements which are substantially identical with the corresponding elements in FIGS. 1-6 are indicated by the same reference numerals.
  • the wall 22 is shown as a separate part rather than as an element which is integrally formed with the housing, as in the previously described embodiment.
  • a set of three balls or spherical members 101, 102 and 103 are located in corresponding holes of a ball guide 108.
  • the balls are held in place both by the ball guide 108 and the intermediate wall 22 located therebelow.
  • Balls 101, 102 and 103 together with guide 108 are disposed below the shim 30 and balance plate 42. When the balance plate is in its extreme low pressure position, it will rest against all three balls 101, 102 and 103.
  • the upper ball guide 114 includes cut out portions 115 and 116 substantially identical to, and aligned with, the corresponding cut out portions 62,63 of the ball stop plate 50. These cut out portions permit passage of the spring rests 54,55 therethrough so that the fingers 58,59 thereof may engage depressions 60,61 of the balance plate 42.
  • the balls 111 and 102 are aligned vertically with each other and are so spaced from each other as to preclude any substantial vertical movement of the balance plate 42 therebetween.
  • the function of the balls 111 and 102, together, is analogous to that of ball 48 in the previously described embodiment.
  • Each of the alternating axes, shown as A and B in FIG. 7, pass through the vertical line between balls 102 and 111.
  • Ball 101 serves merely as a stop or rest for the balance plate 42 when it is in its low pressure position.
  • Ball 103 also serves this purpose, but, in addition, also serves to partially define the axis A about which the balance plate pivots during the initial stroke of the diaphragm.
  • the axis A is fully defined by the points of engagement of the balls 102 and 103 with the balance plate.
  • the fact that the shim 30 has spokes 32 between the outer rim 31 and hub 33 permits the balls 10], 102 and 103 to protrude through the open spaces between the spokes and engage the balance plate.
  • the pivotal axis B is defined by the points of contact of balls 110 and 111 with the upper surface 44 of the balance plate 42.
  • Ball 111 is larger in diameter than ball 110 and it may continuously engage the balance plate at all times (but it is also possible that a very small clearance may, at times, exist).
  • FIG. 8 shows a modification to the balance plate and ball arrangement of FIGS. 1-6. Rather than providing a single ball 48 staked into the balance plate so as to extend from both the top and bottom surfaces thereof, balls 120 and 121 are provided on either side of a simple chambered hole 124.
  • balls as elements .of the complete stop means in all .of the above-described embodiments, is highly advantageous, since balls can be easily manufactured to very close tolerances. This is important here, where the displacements involved are very small. Also, the fact that metal balls can easily be hardened is important where, as here, they will be subjected to considerable wear.
  • FIG. 9 illustrates an additional embodiment of the present invention utilizing a beam 150 in place of the balance means 42 of the previously described embodiments.
  • tension springs 152, 153 are used in place of the compression springs 52,53 of the other embodiments.
  • the same type of microswitch 78 and actuating button 82 therefor are used with this embodiment.
  • a pressure connection 14 communicates with a chamber 4 defined by a bottom end wall 2 and a diaphragm 6.
  • the diaphragm is attached to a piston 18 which in turn is connected to an elongated vertical rod 155 engaging the central portion of the balance beam 150.
  • Each end of the balance beam includes recessed portions 158 and 159, each recessed portion being effective to provide a pair of downwardly facing surfaces 160 and 162, 163 anc 165 at its respective end.
  • Tension coil springs 152 and 153 are connected near the ends of the balance beam adjacent the lowermost of the downwardly facing surfaces 162,165 at each end. The uppermost of the downwardly facing surfaces 160,163 are adapted to engage with stop means 168,169 secured to the housing.
  • Tension spring 153 is adjusted to be the low pressure spring and tension spring 152 is adjusted to be the high pressure spring.
  • the arrangement is analogous to that of compression springs 52 and 53 of the embodiments previously described.
  • An additional stop 171 is located on the side of the balance beam to which low pressure spring 153 is attached and is positioned to engage an upwardly facing top surface 173 on the balance beam.
  • the arrangement of the springs and stops is such that, on each end of the balance beam, the line of force of the respective tension spring coincides with the point or points of contact of the respective stop or stops with the corresponding surface or surfaces of engagement on the balance beam.
  • the points of contact of the stops 168 and 171 with the surfaces 160 and 173 define the fulcrum points about which the balance beam 150 alternately pivots.
  • the stops 168 and 171 define the fulcrum points for the alternating pivotal movement of the balance beam. It will be further appreciated that these fulcrum points are aligned with the line of force of the adjacent tension spring. In this way, the spring adjacent a given fulcrum is rendered completely ineffective during rotation of the balance beam about that fulcrum. Therefore, similarly to the situation in the other embodiments, the individual springs 152 and 153 operate completely independently of each other.
  • the operation of the microswitch with respect to the movement of the balance beam is identical to the operation thereof with respect to the movement of the balance plate 42 in the other embodiments.
  • the device illustrated in FIG. 9 possesses the same capabilities of full-scale independent pressure differential and pressure range adjustment.
  • a control device comprising:
  • a sensing means defining a wall of said chamber, said sensing means being displaceable through a stroke
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means associated with both said first and second sides of said balance means to define first and second axes about which said balance means pivots;
  • a pair of biasing means at least one of which being adjustable and each having a line of force acting on said balance means, said biasing means being positioned with respect to said balance means such that the line of force of one of said pair passes through said first axis at all positions of said balance means and the line of force of the other of said pair passes through said second axis at all positions of said balance means;
  • control means operatively coupled to said balance means
  • said balance means is a balance plate
  • said stop means includes a first portion and a second portion
  • said stop means of said first portion includes a plurality of stops spaced apart from each other to define said first axis;
  • said stop means of said second portion includes a plurality of stops spaced apart from each other to define said second axis.
  • said first portion of said stop means is associated with said first side of said balance plate
  • said second portion of said stop means is associated with said second side of said balance plate.
  • microswitch is a single pole, double throw microswitch.
  • said housing has first and second ends
  • an inlet means communicates with said chamber, said inlet means being disposed in said first end;
  • an adjusting means is disposed at said second end and is accessible from the exterior of said housing.
  • each of said biasing means is elongated, the longitudinal axis of one of said biasing means passing through said first axis, the longitudinal axis of the other of said biasing means passing through said second axis.
  • stop means include:
  • a control device as defined in claim 9 wherein said protrusions are formed by a plurality of spherical members, some of which have a first part extending from said first side of said balance means and others of which have a second part extending from said second side of said balance means.
  • said stop means include:
  • a second set of protrusions disposed in said housing apart from and above said balance means, said second set being adapted to engage said second side of said balance means.
  • a control device comprising:
  • a sensing means displaceable through a stroke, said sensing means dividing said housing into a sensing chamber and a control chamber;
  • a pair of adjustable biasing means coupled with said balance means, said biasing means being adjusted to exert different biasing forces on said balance means, whereby movement of said sensing means through one part of its stroke effects pivoting of said balance means about one axis, and movement of said sensing means through another part of its stroke effects pivoting of said balance means about the other axis; a single control means associated with said housing, said control means having a casing means and a single displaceable actuator extending outside said casing means, said actuator being operatively connected to said balance means; and
  • said control means having a first control mode at a first position of said actuator and a second control mode at a second position of said actuator, whereby pivoting of said balance means about one of said axes effects movement of said actuator through said first position and pivoting of said balance means about the other of said axes effects movement of said actuator through said second position so that adjustment of said biasing means effects adjustment of said control modes.
  • said balance means includes first and second sides;
  • said stop means are associated with said first and second sides.
  • said balance means is a balance plate
  • said stop means include a first portion and a second portion
  • said stop means of said first portion include a plurality of stops spaced apart from each other to define said first axis;
  • said stop means of said second portion include a plurality of stops spaced apart from each other to define said second axis.
  • said first portion of said stop means is associated with said first side of said balance plate
  • said second portion of said stop means is associated with said second side of said balance plate.
  • control device as defined in claim 15 wherein said control means is a microswitch.
  • a control device comprising:
  • a sensing means defining a wall of said chamber, said sensing means being moveable through a stroke
  • stop means cooperating with said balance plate to define first, second and third axes, said stop means including a low pressure part, a high pressure part and a pivotal part, said first axis passing through said low pressure part and said pivotal part of said stop means said second axis passing through said high pressure part and said pivotal part of said stop means, said third axis passing through said high pressure part and said low pressure part, said pivotal part of said stop means being spaced from said third axis;
  • a pair of biasing means at least one of which being adjustable, operatively coupled to said balance plate and adjusted to exert different biases, whereby movement of said sensing means through one portion of its stroke effects pivoting of said balance plate about said first axis and movement of said sensing means through another portion of its stroke effects pivoting of said balance plate about said second axis;
  • control means associated with said housing, said control means having an actuation means effectively connected to said balance plate approximately on said third axis, whereby small displacements of said balance plate at said pivotal part of said stop means are not transmitted to said actuation means.
  • said actuation means includes a resilient means attached to said balance plate;
  • said actuation means further includes an actuating post between said resilient means and said control means;
  • said resilient means includes an extension thereon which is directed away from said pivotal part of said stop means and toward said midpoint.
  • a control device comprising:
  • a balance beam means having first and second ends
  • balance beam means in the region of at least one of said ends;
  • said stop means defining first and second fulcrums about which said balance beam means pivots;
  • a pair of biasing means at least one which being adjustable and each having lines of force acting on said balance beam means, the line of force of one of said pairs passing through said first fulcrum and the line of force of the other of said pairs passing through said second fulcrum;
  • control means operatively coupled to said balance beam means
  • a control device comprising:
  • a displaceable sensing means defining a wall of said chamber
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means associated with both said first and second sides of said balance means to define first and second axes about which said balance means pivots;
  • each of said rotatable screw means being associated with one of said biasing means for adjusting the bias thereof;
  • said pair of rotatable screw means having mutually overlapping portions thereon;
  • control means operatively coupled to said balance means
  • a control device comprising:
  • a displaceable diaphragm means defining a wall of said chamber
  • said diaphragm means engaging a piston displaceable within a cylinder member
  • said diaphragm including an annular convolution thereon, the formation of said convolution being by chamber pressure and being facilitated by the pivotal freedom of said piston.
  • a control device as defined in claim 1 including a resilient means between said control means and said balance means, said resilient means being sufficiently weak to effect a lost motion connection between said balance means and said control means during the pivotal movement of said balance means about both of said axes.
  • said pair of biasing means is a pair of compressible coil springs
  • each guide means also being connected to said housing at a connection point;
  • each connection point being associated with one of said springs and located at that part of said housing most remote from said one associated spring.
  • a control device as defined in claim 2 including:
  • said pair of rotatable screw means having mutually overlaping portions thereon.
  • each of said biasing means has a line of force acting on said balance means, said biasing means being positioned with respect to said balance means such that the line of force of one of said biasing means passes through one of said axes at all positions of said balance means and the line of force of the other of said biasing means passes through the other of said axes at all positions of said balance means.
  • a control device as defined in claim 15 including a resilient means between said actuator and said balance means, said resilient means being sufficiently weak to effect a lost motion connection between said balance means and said actuator as said actuator moves between its first and second positions.
  • a control device as defined in claim 15 including:
  • said pair of rotatable screw means having mutually overlaping portions thereon.
  • sensing means is a diaphragm
  • said diaphragm including an annular convolution thereon, said convolution being formed by pressure and being effective to center said piston within said cylinder.
  • each of said biasing means has a line of force acting on said balance plate, said biasing means being positioned with respect to said balance plate such that the line of force of one of said biasing means passes through one of said axes at all positions of said balance plate and the line of force of the other of said biasing means passes through the other of said axes at all positions of said balance plate.
  • a control device comprising:
  • sensing means being displaceable through a stroke
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means cooperating with both said first and second sides of said balance means to define first and second axes about which said balance means pivots, said stop means including a low pressure part, a high pressure part, and a pivotal part, said first axis passing through said low pressure part and said pivotal part of said stop means, said second axis passing through said high pressure part and said pivotal part of said stop means, said pivotal part being spaced from a line passing through said high pressure part and said low pressure part.
  • a pair of biasing means at least one of which being adjustable and each having a line of force acting on said balance means, said biasing means being positioned with respect to said balance means such that the line of force of one of said pair passes through said first axis at all positions of said balance means and the line of force of the other of said pair passes through said second axis at all positions of said balance means;
  • control means operatively coupled to said balance means
  • a control device comprising:
  • a sensing means defining a wall of said chamber, said sensing means being displaceable through a stroke
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means cooperating with both said first and second sides of said balance means to define first and second axes about which said balance means pivots, said stop means including a low pressure part, a high pressure part, and a pivotal part, said first axis passing through said low pressure part and said pivotal of said stop means, said second axis passing through said high pressure part and said pivotal part of said stop means, said pivotal part being spaced from a line passing through said high pressure part and said low pressure part;
  • a pair of adjustable biasing means coupled with said balance means, said biasing means being adjusted to exert different biasing forces on said balance means, whereby movement of said sensing means through one part of its stroke effects pivoting of said balance means about one axis, and movement of said sensing means through another part of its stroke effects pivoting of said balance means about the other axis; g. a single control means associated with said housing, said control means having a casing means and a single displaceable actuator extending outside said casing means, said actuator being operatively connected to said balance means; and
  • said control means having a first control mode at a first position of said actuator and a second control mode at a second position of said actuator, whereby pivoting of said balance means about one of said axes effects movement of said actuator through said first position and pivoting of said balance means about the other of said axes effects movement of said actuator through said second position so that adjustment of said biasing means effects adjustment of said control modes.
  • a control device comprising:
  • a sensing means defining a wall of said chamber, said sensing means being displaceable through a stroke
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means associated with both said first and second sides of said balance means to define first and second axes about which said balance means pivots;
  • each biasing means being elongated and each having a line of force acting on said balance means, the line of force of each biasing means coinciding with the longitudinal axis thereof, said biasing means being positioned with respect to said balance means such that the line of force of one of said pair passes through said first axis at all positions of said balance means and the longitudinal axis of the other of said pair passes through said second axis at all positions of said balance means,
  • control means operatively coupled to said balance means
  • a control device comprising:
  • a sensing means defining a wall of said chamber, said sensing means being displaceable through a stroke
  • a balance means having first and second sides, said sensing means being operatively coupled to said balance means;
  • stop means associated with both said first and second sides of said balance means to define first and second axes about which said balance means pivots;
  • said stop means including a plate disposed in said housing above said balance means, a wall disposed in said housing below said balance means, a plurality of spherical members extending from both said first and said second sides of said balance means, said members of said first side being adapted to eni. whereby displacement of said sensing means through one part of its stroke effects pivoting of said balance means about said first axis and displacement of said sensing means through another part of its stroke effects pivoting ofsaid balance means about said second axis.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Indication Of The Valve Opening Or Closing Status (AREA)
  • Valve Device For Special Equipments (AREA)
US00236732A 1971-05-31 1972-03-21 Condition responsive control device with capacity for independent adjustment of control points Expired - Lifetime US3786212A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MX4415571 1971-05-31
US23673272A 1972-03-21 1972-03-21

Publications (1)

Publication Number Publication Date
US3786212A true US3786212A (en) 1974-01-15

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ID=26640837

Family Applications (1)

Application Number Title Priority Date Filing Date
US00236732A Expired - Lifetime US3786212A (en) 1971-05-31 1972-03-21 Condition responsive control device with capacity for independent adjustment of control points

Country Status (11)

Country Link
US (1) US3786212A (de)
JP (1) JPS5219308B1 (de)
AU (1) AU472992B2 (de)
BE (1) BE784213A (de)
CA (1) CA966175A (de)
CH (1) CH553339A (de)
DE (1) DE2224026C2 (de)
FR (1) FR2166854A5 (de)
GB (1) GB1381654A (de)
IT (1) IT955906B (de)
NL (1) NL168362C (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911238A (en) * 1973-12-06 1975-10-07 Automatic Switch Co Condition responsive control device with capacity for independent adjustment of control points and transducer therefor
US4467155A (en) * 1982-05-06 1984-08-21 Dresser Industries, Inc. Electrical switch apparatus
CN110391110A (zh) * 2019-09-04 2019-10-29 济南迈克阀门科技有限公司 一种消防用双输出式可调压压力开关

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3239129C2 (de) * 1982-10-22 1986-01-16 H. Kuhnke Elektrotechnik GmbH, Büttikon PE-Wandler

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US2873332A (en) * 1956-02-01 1959-02-10 William J Williams Adjustable differential switch actuator
FR1263541A (fr) * 1959-07-13 1961-06-09 Gen Motors Corp Mécanisme de commutation sensible à la vitesse
US3098141A (en) * 1942-12-31 1963-07-16 Wintriss George Enclosed precision switch
US3182150A (en) * 1962-05-25 1965-05-04 Robertshaw Controls Co Pneumatic-electric switch
US3210486A (en) * 1960-11-08 1965-10-05 Holzer Walter Pressure operated switch with bearing member plate
US3235692A (en) * 1962-11-30 1966-02-15 Ametek Inc Condition responsive sequence switch
US3303306A (en) * 1963-07-25 1967-02-07 Bosch Gmbh Robert Membrane switch with first and second independently movable portions
US3390242A (en) * 1967-03-10 1968-06-25 Illinois Tool Works Switch mechanism utilizing a single spring element to provide lost motion

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Publication number Priority date Publication date Assignee Title
US2284940A (en) * 1939-08-04 1942-06-02 Honeywell Regulator Co Snap action device
US2266144A (en) * 1939-08-04 1941-12-16 Honeywell Regulator Co Automatic switching device
US2766349A (en) * 1954-02-16 1956-10-09 Matthew Kuziak Differential pressure switch

Patent Citations (8)

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Publication number Priority date Publication date Assignee Title
US3098141A (en) * 1942-12-31 1963-07-16 Wintriss George Enclosed precision switch
US2873332A (en) * 1956-02-01 1959-02-10 William J Williams Adjustable differential switch actuator
FR1263541A (fr) * 1959-07-13 1961-06-09 Gen Motors Corp Mécanisme de commutation sensible à la vitesse
US3210486A (en) * 1960-11-08 1965-10-05 Holzer Walter Pressure operated switch with bearing member plate
US3182150A (en) * 1962-05-25 1965-05-04 Robertshaw Controls Co Pneumatic-electric switch
US3235692A (en) * 1962-11-30 1966-02-15 Ametek Inc Condition responsive sequence switch
US3303306A (en) * 1963-07-25 1967-02-07 Bosch Gmbh Robert Membrane switch with first and second independently movable portions
US3390242A (en) * 1967-03-10 1968-06-25 Illinois Tool Works Switch mechanism utilizing a single spring element to provide lost motion

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911238A (en) * 1973-12-06 1975-10-07 Automatic Switch Co Condition responsive control device with capacity for independent adjustment of control points and transducer therefor
US4467155A (en) * 1982-05-06 1984-08-21 Dresser Industries, Inc. Electrical switch apparatus
CN110391110A (zh) * 2019-09-04 2019-10-29 济南迈克阀门科技有限公司 一种消防用双输出式可调压压力开关
CN110391110B (zh) * 2019-09-04 2024-04-26 济南迈克阀门科技有限公司 一种消防用双输出式可调压压力开关

Also Published As

Publication number Publication date
AU472992B2 (en) 1976-06-10
JPS5219308B1 (de) 1977-05-27
BE784213A (fr) 1972-09-18
CH553339A (de) 1974-08-30
CA966175A (en) 1975-04-15
NL7207353A (de) 1972-12-04
DE2224026A1 (de) 1972-12-14
IT955906B (it) 1973-09-29
NL168362B (nl) 1981-10-16
AU4264472A (en) 1973-11-29
FR2166854A5 (de) 1973-08-17
NL168362C (nl) 1982-03-16
DE2224026C2 (de) 1984-03-29
GB1381654A (en) 1975-01-22

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