Abstract: A pressure switch has a housing with a mounting bracket and a flexible diaphragm defining a wall of the pressure sensing cavity in the housing. Movement of the diaphragm operates an electric switch. The diaphragm is spring biased and an adjustment arm is frictionally mounted in a pair of guide surfaces on the mounting bracket. The arm contacts a cap on one end of the bias spring and is movable in the guide surfaces for adjusting the position of the spring cap for calibration. The mounting bracket is mounted to the housing by inserting a lug on the bracket in a recess in the housing and crimping a folded tab on the bracket to engage another recess in the housing. In another embodiment using a housing of all molded plastic, the adjustment arm frictionally engages a slot molded in the housing and is moved in the slot for calibration.

Abstract: A sliding type adjustment mechanism for changing settings of a diaphragm type pressure switch adjusted by moving an external lever to move a plunger for changing the preload on the diaphragm. An external metal mounting bracket has a pair of spaced parallel slots which serve as ways. A plastic slider with a cam surface engaging the lever has a pair of lugs, each of which engages one of the slots for guiding the slider on the bracket. The slider has an integrally formed spring tab providing friction against the bracket to hold the slider in a selected position. A recess in the bracket relieves the tab friction at the limit of the slider travel to allow the lever to bias a steep-ramp portion of the cam surface to move the slider to an initial position.

Abstract: A pressure control for use in applications such as refrigeration, air conditioning and ice generating machinery includes a highly accurate snap acting switch, field adjustable trip points and reset points and a reference scale. The trip point is adjusted by means of an adjustment screw, while the reset point is adjusted by changing the differential, or the difference between the trip point and reset point. The differential is adjusted by adjusting the amount of "lost motion" within the control by employing an actuator which includes a cam surface and means for changing the position of the cam surface.

Abstract: A trip controller for a wafer processing system provides for adjustable hysteresis and autocalibration. Adjustable hysteresis implements different trip points for upward pressure changes and downward pressure changes in the wafer processing chamber. Autocalibration is implemented using a digital potentiometer with on-chip storage. The trip controller provides more reliable operation than conventional single trip-point indicators. Yet, the inventive trip controller is readily inserted as a replacement in systems formerly using conventional trip controllers. Further advantages include a single-rail power supply and flexibility to adapt to different systems requiring trip controllers.

Abstract: A pressure operated switch construction, parts therefor and methods of making the same are provided, the pressure operated switch construction comprising a housing having an external surface and carrying an electrical switch unit and a diaphragm assembly therein, and a compression spring unit carried by the housing and being interconnected to the switch unit and the diaphragm assembly to control the operation thereof in relation to the compressive setting of the spring unit, the housing having a bracket member extending outwardly from the external surface thereof in a flangelike manner and having first structure for mounting a first movable actuator unit to the housing that is to be interconnected to the spring unit to select the desired compressive setting thereof, the switch construction comprising a bracket interconnected to a second structure of the bracket member, and a second movable actuator carried by the bracket and being interconnected to the spring unit to select the desired compressive setting the

Abstract: The present invention pertains particularly to low pressure level type switches employed for sensing the water level in washing appliances. The invention employs a slidable strip or tab interposed between the diaphram pre-load spring and the reaction stop for the spring. In one position the thickness of the movable tab increases the pre-load on the spring by an amount equal to the thickness of the tab. In a secod position the pre-load stop extends through a cutout in the tab and contacts the spring reaction member directly.

Abstract: An adjustable pressure responsive switch assembly includes a unitary slide cam and button with projections extending outwardly from the slide cam. The support bracket mounted on the pressure switch includes an elongated slot having an enlarged opening at one end. The slide cam projections are adapted to be inserted in the enlarged opening and then be slidingly received in the elongated slot. The slide cam cannot be removed from the bracket unless it is moved all the way to one extreme so that the projections can be removed from the enlarged opening. This movement is prevented by stops formed as part of the cam.

Abstract: A hermetically sealed, creep acting pressure switch has a sensor assembly comprising a bulged metallic membrane welded between a port fitting and a support. A switch assembly, attached to the sensor assembly, includes a housing which has a switch chamber in which, in one embodiment, a pair of stationary contacts are mounted. A piston having a force receiving surface at one end is biased into engagement with the membrane with an adjustable calibrated force. An electrically conductive contact bridge is mounted on and is movable with the piston. The switch can be normally open or normally closed depending on which side of the contact bridge the stationary contacts are mounted. In an alternate embodiment a miniature switch is mounted in the switch chamber and is adapted to be actuated by the piston.

Abstract: A fluid pressure switch includes a housing with a cylindrical bore, a spring housing bore and a guide bore between the cylindrical bore and the spring housing bore. A shaft member axially disposed in the housing between the bore, has a piston element secured on the end within the cylindrical bore for movement in one direction or another upon a differential between fluid pressure sources as presented to the two opposing surfaces of the piston element. A spring-biasing arrangement is secured to the shaft member on the end within the spring housing bore for opposing movement of the shaft member. The spring-biasing arrangement is adjustable both as to the spring force and as to the spring stop setting. A switch operator member secured to the piston member, spreads contact arms apart upon a predetermined displacement of the piston. The switch operator member has an elliptically-shaped eccentric portion which can be rotated to adjust the point of shaft displacement at which switch operation occurs.

Abstract: A method of manufacturing a control device includes interconnecting a switch segment with a terminal and another switch segment and mounting a plurality of electrical circuit elements within a housing with contact sections of the electrical circuit elements being located in different preselected elevations therein, respectively. The terminal is associated with the housing with the another switch segment extending in overlaying spaced apart relation with the contact sections of the electrical circuit elements located in the housing. A method of operating a control device and a control device are also disclosed.

Abstract: A control unit having a condition selector, an electrical switch, having an actuator unit provided with an adjustable movement differential a condition responsive device for actuating the switch when the condition responsive device senses certain conditions selected by the selector, and a lever arrangement carried by the unit and being operatively associated with the actuator unit of the switch and the device whereby the device can actuate the switch by the lever arrangement, the lever arrangement having a first adjustable lever operatively interconnected to the selector and acting as a main range lever. The first lever is operatively interconnected to the condition responsive device and to the actuator unit of the switch. The lever arrangement has a second adjustable lever operatively interconnected to the selector for and to the actuator unit of the switch adjusting the movement differential of the actuator unit of the switch.

Abstract: The invention relates to a pressure responsive electric switch assembly of a type used as evaporator thermostats for refrigerators. In this unit an actuating element for operating a switch is held in equilibrium by two springs acting in opposition to a bellows which is connected to a temperature sensor capsule containing a liquid-vapor filling. An abutment arrangement is provided for the springs so that, despite a constantly rising pressure in the bellows, the actuating element operated by the bellows has a zero or null displacement range which corresponds to a substantial intermediate pressure range to which the bellows is subjected by the temperature sensor. As there is no movement by the actuating element in this intermediate range, there is an avoidance of wear which would otherwise be caused by this movement.

Abstract: An industrial type switch having modular parts which may be assembled so the switch may be used in a wide range of installations. The switch includes a differential module which is easily adjustable to operate over a selected range of pressures, a plug-in snap switch module so the switch may be easily wired and serviced, a range module so the response of the switch to pressures within a range may be readily accomplished, and any one of a plurality of different type actuator modules which are mountable on the exterior of the switch so the switch may be used in a large variety of different type installations.

Abstract: The invention relates to an electric switch assembly of the type operated by a thermostatic bellows, for use on refrigerators. The operating bellows is part of a system having a liquid/vapor filling and the movement of the bellows operates a microswitch. A hinged arm which operates the microswitch is biased in a switch closing direction by the bellows and in a switch opening direction by a spring system which includes a main spring and a differential spring in series. The force displacement line of the spring system approximates the force displacement line of the bellows and has two segments with different slopes. The two segments are formed by arresting the movement of the differential spring to make it ineffective at an intermediate point in the displacement of the bellows. The first segment with a lesser slope represents the action of both springs in series while the other segment, of greater slope, represents only the main spring.

Abstract: A snap-action pressure switch has an adjustable trip point for controlling the switching pressure. A flexible bracket has a bearing portion pivotally mounting a lever between the ends thereof. Contact means are actuated by one end of the lever. A toggle spring is biased between the other end of the lever and a pressure-responsive actuator for causing snap-action pivoting of the lever when the toggle spring passes through an overcenter force-reversing toggle point as the actuator moves in response to pressure. The bearing portion of the flexible bracket is adjustably movable with respect to the actuator, thus moving the pivot point of the lever to change the toggle point of the spring with respect to movement of the actuator, whereby to afford an adjustable switching pressure. The trip point is further controlled by an adjustble range spring biasing the actuator against pressure-induced movement.

Abstract: A pressure operated electrical switch construction having a housing provided with a pressure responsive actuator and an electrical switch operatively associated with the actuator so that the actuator will operate the switch from one condition thereof to another condition thereof when the sensed pressure reaches a predetermined pressure. A reset device is carried by the housing for resetting the switch from the other condition thereof back to the one condition thereof. A range spring is carried by the housing for acting on the actuator to provide the predetermined pressure. A reset spring, forming part of the reset device, acts on the actuator to reset the switch. The two springs are concentrically disposed with one of the springs being disposed completely inside the other spring to render the switch construction compact even though the switch construction has a fixed reset or a proportional reset.

Abstract: A fluid operated electrical switch construction having a first housing provided with an electrical switch therein and a second housing having an expandible and contractible fluid operated power element therein, the housings being secured together in a predetermined assembled relationship so that a motion transmitting arrangement is disposed in both of the housings and extends between the power element and the switch to transmit movement of the element to the switch to operate the same. The motion transmitting arrangement has a length adjustment unit therein that is adapted to be adjusted by first causing relative movement between the housings while the housings are assembled together but before the same are secured together so that once the adjustment unit has been adjusted to provide the proper length, the housings are secured together in such assembled relation.

Abstract: A condition responsive electrical switch is provided with a housing, and means is movable in the housing between opposite positions for controlling the flow of power through the switch. Means is pivotally movable in the housing for effecting actuation of the controlling means between its opposite positions, and means is operable generally in response to a certain condition for driving the actuation means to pivot it and conjointly move the controlling means toward one of its opposite positions. Means is selectively operable for biasing the actuation means against the driving means to also pivot the actuation means and effect conjoint movement of the controlling means toward the other of its opposite positions.A method of operating a condition responsive electrical switch and a control system are also disclosed.

Abstract: A simplified calibration mechanism is provided for a pressure switch using an adjustable, spring-biased plunger arrangement for controlling the trip force and hence the pressure to which the switch responds. The mechanism includes an especially configured lever pivoted at one end, contacting an especially shaped cam as a follower at its other end and the plunger at its mid portion. First calibration means are provided in the lever's pivoted end to adjust the normal low-high pressure settings of the switch. Second calibration means are provided to isolate the lever and cam from the plunger for effecting a precise setting of the pressure switch at extra-low pressures.