Abstract: A valve operator utilizes a disconnectable worm gear arrangement to drive a valve spindle. An hand crank may be used to disengage the power-driven worm gear arrangement and to manually drive the valve spindle, if necessary, by pivoting a bracket holding the end of the worm shaft. The worm gear is self-locking so that reaction forces from the valve cannot move the worm gear. A torque-sensing lever, responsive to axial movement of a highly torqued drive shaft, pivots against the force of a biasing spring to operate a microswitch to cut off electrical power to the drive motor for the valve operator should the torque exceed a predetermined amount. Additional protection against torque overload is provided by an adjustable mechanical clutch which operates in the event of control element failure or misadjustments. One or more microswitches, adjustable in position, are engaged by a traveler which moves along a lead screw driven by a gear arrangement coupled to the valve spindle to control operation of the actuator.

Abstract: A roller shutter door limit sensing means comprising a screw member for rotation in response to rotation of the drum onto which the curtain of the roller shutter door is wound, a limit switch actuator means threadably carried by the screw member to advance or retreat therealong in response to its rotation operates a corresponding opposite limit switch means, whereby the switch means can be activated for the curtain fully closed or the curtain fully opened positions whereby to switch off an electric drive means which opens or closes said roller shutter door.

Abstract: This invention is directed to a valve drive means for a vertical up-down valve of the type having a valve shaft linearly movable within a cylindrical valve bore between a first, normal, valve position and a second, occasional valve position. The drive means includes a vertical rotatable drive shaft with a threaded portion formed between non-threaded portions and a mateably threaded coupler for engaging the drive shaft and transmitting axial force to the valve shaft. The movement of the valve shaft is precisely limited by disengagement of the coupler from said threaded drive shaft portion irrespective of continued rotation of said drive shaft. Means are included for neutralizing hydraulic pressure which would interfere with re-engagement of the coupler with the threading on the drive shaft. Means are also preferably provided for deriving a torque component for rotating said valve shaft within said bore and thus facilitating any "freezing" of seal rings mounted to said valve shaft within said valve bore.

Abstract: A linear actuator for providing a thrust force for actuating various movable members, such as, for example lever arms, cranks, slides and valve flaps. The thrust force is applied by an extension rod that is arranged within a housing so as to extend in an axial direction along the housing and out from the housing. The extension rod has a load connector mounted on the end outside of the housing for connection to the movable member to which the thrust force is to be applied. A drive screw is attached to the extension rod so that rotation of the drive screw is translated into an axial displacement of the extension rod. A drive motor serves to rotate the drive screw. Either when a blockage of the movable member occurs or when the extension rod has reached the end of its path of travel, any attempt for continued movement of the extension rod significantly increases the thrust force applied to the rod.

Abstract: A device for controlling the movements or operating cycles of models, for example, model airplanes, model ships, kites, etc., which are driven by a drive motor is provided which includes a screw spindle which is affixed at about the center of a shaft which is coupled with the motor drive shaft. An internally-threaded element, preferably a nut, is longitudinally guided on the screw spindle for actuating the operating cycle in one or the other direction. At the two protruding ends of the shaft, a spiral spring is disposed which urges a washer against the screw spindle in such a way that when the element becomes unscrewed from either end of the screw spindle, the element is retained in a free-running position, and during the reverse rotation of the motor drive shaft, the element is pushed in a counter direction whereupon it is screwed onto the screw spindle.

Abstract: An end switch for use with a shaft and a drive which drives the shaft through a relatively large number of 360.degree. angular rotations associated with an end position wherein the end switch is provided with a switching member and with a spindle drive means responsive to the drive for causing an end face of the switching member to be brought into engagement with a contact of a stationary switch at the end of the rotation of the shaft. In accordance with the invention, the spindle drive means moves the switching member axially thereto during a first portion of the shaft rotation and tangentially thereto during the remaining portion of the shaft rotation, the former portion being larger than the latter portion.

Abstract: A sliding door of the type employed in public transport vehicles and driven by an electric motor comprises at least one door-leaf coupled with a nut mounted on an endless screw which is driven in rotation in order to open and/or close the door. The nut is displaced in translational motion within a guide which prevents rotational motion. The locking device comprises means for interrupting the translational displacement of the guided nut at the end of travel and for permitting angular rotation of the nut with the endless screw, means for limiting the angular displacement of the nut and finally means for limiting the translational motion of the nut if it is displaced along the endless screw and no longer engaged in the guide.

Abstract: An automatic piston drive mechanism for use in dispensing flowable compound material through an orifice of a housing in which the material is contained. The housing may be that of a caulking gun or else that of a cartridge as insertable on a carriage of a caulking gun support frame. The drive mechanism comprises a piston member having an elongated rod and a pusher head. A drive motor is provided for imparting longitudinal displacement of the rod. A clutch member is rotatably driven by the drive motor and releasably connected to the rod to impart axial rotation thereto to effect axial displacement whereby the pusher head will apply pressure to the compound to push it through the dispensing orifice.

Abstract: An electromechanical actuator is provided which is capable of disconnecting the output shaft and the drive mechanisms in such a way that, in the event of either a rotational or translational failure during operation, the output shaft can be effectively freed in such a manner that it will not resist the motion produced by other actuators which have not failed.

Abstract: A switching bearing assembly for a motor-driven spindle, e.g. a leadscrew adapted to drive a nut axially along the leadscrew, is provided with a bearing housing disposed between two fixed plates and biased centrally thereof by a plurality of compression springs. The housing is positioned to actuate switches which turn off the motor when the spindle bearing is overloaded, e.g. when the nut reaches the end of its travel or is otherwise impeded in its first axial movement. The housing is also provided with a spring-biased pin which bears upon an eccentric carried by the shaft to frictionally retard further rotation thereof once the motor has been turned off.

Abstract: A spring resistance cartridge assembly for a valve actuator is disclosed which offers resistance to movement in either direction of an axial member extending therein. The cartridge assembly has a base plate securable to an axial member and an opposing fixed plate which is secured in a non-movable position. Between the base plate and the fixed plate are two compression plates having spring members trapped therebetween. Bolts and studs attach the compression plates one to each, the base plate and the fixed plate.

Abstract: A garage door operator includes a drive screw, rotationally and longitudinally movable in a shuttle track or guide rail, and a screw-driven shuttle mounted on the track and connected to the door. A lever arm is attached to the screw at a rearward end thereof and is pivoted to the operator at one side of the screw. Another end of the lever arm, adjacent an opposite side of the screw, is operatively disposed with respect to control switches and is spring-loaded, whereby door engaged obstructions cause the rotating screw to move longitudinally, against the spring bias, and to actuate, through the lever arm, a switch for stopping or for reversing the operator motor. A sleeve coupling permits longitudinal screw movement with respect to the operator's motor, and is provided with means to permit continued motor operation, drivingly disengaged from the screw, upon control malfunction, in order to prevent damage or injury.

Abstract: Limit stop apparatus wherein a driven shaft rotates a predetermined number of revolutions in either direction whereupon a travelling nut assembly contacts a shock absorbing stop to terminate shaft rotation by frictionally jamming screw threads between the nut assembly and the driven shaft. Outer and inner portions of the nut assembly are connected for limited relative rotational motion on non-jamming auxiliary threads, thus permitting the driven shaft to be backed off to release the nut assembly from the shock absorbing stop and thereby release the jammed threads with a minimum of available torque. By this structure, locking of the limit stop at either end is prevented.

Abstract: An apparatus for cocking a breechblock of an automatic firing weapon equipped with an electric motor which is operatively connected through the agency of an electromagnetic coupling with a displacement mechanism for the breechblock in order to move the breechblock into its cocked position, an electric switch which, upon reaching the cocked position, cuts-off the coupling. An overload device is provided which upon exceeding a certain value of the displacement resistance of the breechblock actuates the electric switch for cutting-out the coupling.