Abstract: A machine suitable for placement in a freezer for making slush or ice cream in a cylindrical container. The machine comprises a platform which is lengthwise adjustable, at least four rollers which have an adjustable distance support container, a driving means to drive the rollers and rotate the container, a scraping means disposed on the shaft of the container to scrape freezing slush or ice cream and to be used as a second safety means, and a first safety means which comprises a base plate, a control plate and a flexible element engaged together. When the slush or ice cream is hard enough, the control plate and the flexible element will rotate respective to the base plate so that the shaft will rotate together with the container. Further, even if the first safety means is out of order, the scraping means will free from the shaft of the container, then the scraping means will rotate together with the container in order to be used as a second safety means.

Abstract: A clutch for mechanically and electrically disconnecting the servo drive of a reciprocable transfer mechanism comprises a housing having bores for the acceptance of a reciprocable piston and a transfer bar, respectively, said piston having a roller and said transfer bar having a groove for the acceptance thereof, and resilient means normally biasing the roller on said piston into the groove on said transfer bar whereby movement of said housing normally effects like movement of said transfer bar, movement of said roller out of the groove in said transfer bar effecting simultaneous mechanical disconnect of said servo drive and opening of a switch to effect electrical disconnect of said servo drive.

Abstract: A nut/clutch assembly for a rotary power screw, such as a linear actuator power screw, is disclosed in which the power screw is selectively rotated in one direction or the other, and in which the power screw has a pair of stops spaced apart from one another and which are rotatable with the power screw. A nut is provided having a central opening threadably engageable with the power screw, and the nut is threadably movable in axial direction along the power screw upon rotation of the latter. The nut has a circumferential groove thereon, and this groove has a base and a pair of spaced side walls. A collar is slidably received within the circumferential groove, and the collar is resiliently clamped onto the nut such that the collar frictionally engages the grooved base with a desired frictional force so as to permit the nut to rotate relative to the collar upon the nut being rotatably driven by the screw, and upon the collar being held in fixed rotary position.

Abstract: A gearing unit has a housing containing gearing drivably interconnecting a rotary input to an output shaft used to propel a drive chain of a mineral mining machine. A clutch is provided which is released by hydraulic pressure to disengage the drive automatically should excessive loading occur. A spigot rotatably locked to the shaft provides a fluid passage for hydraulic fluid used to release the clutch and the fluid flow is controlled by an electromagnetic valve. A torsion bar carrying a load sensor is located within the spigot and the sensor provides an electrical signal transferred to control means for operating the valve via a slip-ring system. The torsion bar is rotatably locked to the shaft via a coupling rod disposed within the shaft and a push-in connection. The torsion bar is also rotatably secured to the spigot for easy release therefrom.

Abstract: An override for a positive drive mechanism which includes a first bearing block which is fixedly secured to tie rods and a second bearing block which is secured to the tie rods through release and relatch means. The blocks are designed to couple to either a positive drive unit or a unit to be driven by the drive unit. When the driven unit encounters a solid obstruction, release and relatch means associated with the second bearing block will permit the tie rods to slide within the second bearing block, thereby allowing the driven unit to stop. The override mechanism is advantageous in that within a relatively small physical size when a high maximum preselected load in the mechanism is attained, the mechanism will release and apply no further load to the drive. Very long override strokes can be accommodated after which the device will reset at the end of each stroke.

Abstract: The transferred torque is continuously measured at a predetermined machine portion. A torque-dependent comparison signal is generated and compared with a predetermined maximal torque limit value. When the limit value is reached or exceeded, a positioning signal is generated, and the switching element releases the clutch. The generation of the torque-dependent comparison signal is effected in accordance with the measurement function M=M(t)+dM/dt.multidot..DELTA.t. In addition to measuring the transferred torque M(t), the variation dM/dt of the torque M(t) is also detected as a function of time, and subsequently the torque obtained as a comparison signal from the variation dM/dt at the end of a predetermined time interval .DELTA.t following the particular time of measurement is used as a comparison signal. The clutch is preferably formed with end face teeth.

Abstract: A clutch for power screwdrivers. It has a transmission, an adjustable bit stop, and a drive shaft. It also has a cogwheel with cams on one face and a clutch disk with catches on one face mounted on the drive shaft. The object is a low-noise, wear-resistant clutch. The drive shaft is in one piece. An intermediate disk with catches on one face and cams on the other face is positioned between the cogwheel and the clutch disk. A spring mechanism is positioned between the cogwheel and the intermediate disk.

Abstract: A torque limiting clutch having two or more cylindrical magnetic rings with coplanar edges abutted to a flat surface portion at one side of a magnetic driven member which may be a flat plate. The rings may be cylindrically round, or polygonal with flat sides. Between the rings are ring-like, cylindrical, arcuate, or flat permanent magnets conforming to the radial spacing of the rings and maintaining a magnetic circuit or circuits with the driven plate. A flat bar or other mechanical drive means engages the free other edges of the rings and is driven rotationally by a motor drive shaft or other driving means. The driven plate carries a driven shaft, or is adapted for engaging driven gear means or a driven pulley belt.

Abstract: A pushrod assembly including a carriage mounted on a shaft for movement therealong and carrying a pushrod engageable with a load to be moved. A magnet is mounted on a supporting bracket for movement along such shaft. Means are provided for adjustably spacing said magnet away from said carriage to obtain a selected magnetic attractive or coupling force therebetween. Movement of the supporting bracket and the magnet carried thereby pulls the carriage along with it until the selected magnetic force is exceeded by a resistance load acting on the carriage.

Abstract: An overload release mechanism comprising a control plunger, a housing for slidably supporting the control plunger for axial displacement from an advanced coupling position to a retracted release position, the control plunger having a first portion having a first diameter, a second portion having a second smaller diameter and an inclined annular surface joining the first and second portions. The control plunger is maintained at the advanced coupling position until a predetermined axial force is applied and then is axially displaced to the retracted release position by a control ring having an inner diameter substantially the same as the second control plunger diameter made up of a plurality of discrete individual circumferential segments forming a substantially continuous ring when extending around the second control plunger portion.

Abstract: Protection apparatus (15) for use with universal drive shafts (13) and including a sensor (16) mounted in spaced relationship relative to the shaft (13) and actuated when the shaft undergoes a predetermined degree of movement beyond its normal attitude, actuation of the sensor causing drive to be removed from the drive shaft (13) and/or generation of a warning signal.

Abstract: A clutch is interposed between the driving gears of a grinding mill and the driving motor to protect the gears from damage by mechanical overloading. The clutch is set to slip at torques below those required to structurally damage the gears yet higher than design load and the clutch released and the mill is shut down after a preset degree of clutch slippage occurs.

Abstract: An adjustable torque limiting assembly includes a first wrap spring mechanism which provides a readily adjustable torque transmission limit and a second coaxially disposed wrap spring mechanism which provides a mechanical signal that the torque limit has been reached. This signal may be utilized to terminate an energy supply to a prime mover associated with the torque limiting assembly. The first wrap spring mechanism generally includes a wrap spring in which the spring moment and thus the slip or overrunning torque threshold may be readily adjusted. The second wrap spring assembly likewise includes a wrap spring which is activated only subsequent to slip of the first wrap spring and enlarges to engage a concentrically disposed control sleeve. The control sleeve then rotates and activates an associated shut-off mechanism.

Abstract: An impact wrench including a hammer and an anvil to which impacts are imparted by the hammer, the impact wrench comprising a pair of sensors located at a stationary section of the wrench wherein the sensors are electrically arranged so as to have different phases, the sensors being to detect the rebounds occurring on the anvil, a second sensor adapted to detect an angular displacement of the anvil from a time when the rebounds detected by the first sensors exceed a predetermined value, and means for stopping the motor.

Abstract: A driving rotary member which is rotatably fitted around a main shaft is rotated by a driving force from a motor. An intermediate gear is rotatably provided on one surface of the driving rotary member so as to have a different axis from that of the main shaft. A clutch gear having a gear portion, meshing with the intermediate gear and a clutch disk member, is rotatably fitted around the main shaft. A clutch plate is fitted around the main shaft so as to be rotated integrally with the driving rotary member while being brought into contact with the clutch disk of the clutch gear. The clutch plate is brought into contact with the disk of the clutch gear by a contact means. A driven rotary member having a gear portion on an inner surface thereof which meshes with the intermediate gear is also fitted around the main shaft so as to be rotatable together with and relative to the driving rotary member. A driving force transmitted from the driving rotary member is supplied to the antenna by the driven rotary member.

Abstract: The subject invention pertains to a device for operating upon a filter-rod lengths comprising a first conveyor for transferring the filter lengths from a supply outlet to a plurality of further conveyors. The further conveyors carry the filter lengths past a heat rod-forming elements and a barrier-depositing assembly. All the conveyors are driven from a single power source. The first conveyor may be selectively manually disengaged from the power source so that filter-rod lengths which have passed the first conveyor can be cleared from the device before the device is shut down.

Abstract: A gearing unit with planetary gearing employs a load sensor in the form of a stationary pin provided with a strain gauge transducer easily accessible via a bore in its casing. A brake with respective plate carriers is associated with the planetary gearing. One of these carriers is held stationary with the aid of the load sensor while the other of the carriers meshes via teeth with a rotatable component of the gearing. During operation the carriers lock together to hold the component of the planetary gearing stationary to permit drive to be transmitted. The load sensor is then subjected to force proportional to the dynamic loading on the gearing and brake. In the event of overloading the carriers are disengaged by hydraulic force in response to a signal from the sensor to permit the planetary gearing component to rotate and thus interrupts the drive.

Abstract: The disclosure is directed to a clutch or connector mechanism that is capable of having the individual bias changed so that it is independent of the torque applied to the clutch. The driving and driven elements may be interchanged and either the driving or driven elements may have indentations formed at different radii to control the torque at one setting in a first rotational direction and reach a different torque at another setting in an opposite rotational direction. The two rotatable members, one driving and the other being driven, form two bearings that provide loading support within the clutch or connector.

Abstract: The present invention relates to a safety device for an upper die arbor of a fastening machine having a driving sleeve, an upper mold mandrel, a copper sleeve, and a steel sleeve. The driving sleeve has a roller in each of four holes. A flange is formed on the circumference of upper mold mandrel. Due to the positions of the rollers with respect to the flange, and the difference between inside diameters of quadrangular slots formed in the copper sleeve and steel sleeve, when the upper mold mandrel moves downward and is blocked by an undesired object, the rollers pass over the flange and do not exert the normal forming force on the upper mold mandrel. Therefore, the upper mold mandrel does not exert the mechanical crushing force in order to prevent injury to the object.

Abstract: The bidirectional, torque-limiting, drive and brake mechanism has an input and output drive shafts and a helical spring which is normally in interference fit with the mechanism housing and, in the torque transmitting mode of operation, is disengaged to permit torque transmission by a direct mechanical coupling between the input and output drive shafts. The torque-limiting component, which functions to interrupt transmission of rotation from the input drive shaft to the output drive shaft upon a predetermined torque load, is adjustable to a selected predetermined torque load in the field.

Abstract: An improved torque control and fluid shutoff mechanism for a fluid operated tool includes an output shaft with an axially slidable cam sleeve mounted on the shaft. The cam sleeve is coupled with a driven tool bit holder to provide a clutch connection. The cam sleeve is biased for engagement with a cam surface on the tool bit holder whereby during normal operation of the tool, the tool bit holder remains fixed relative to the cam sleeve. When a threshold torque acts on the tool bit holder, the tool bit holder rotates relative to the cam sleeve axially driving the cam sleeve to release a biased kickout sleeve from retaining a radially displaceable member. The radially displaceable member engages a throttle rod and a thrust pin. The throttle rod extends to a fluid control valve which controls inlet fluid. Release of the radially displaceable member from being retained by the kickout sleeve permits axial translation of the throttle rod to terminate fluid flow to the motor of the tool.

Abstract: The invention relates to a torque-limiting clutch. An engagement lock (2, 8, 9, 11, 12) and a friction clutch (6, 20-26) disengageable counter to the force of an axially acting spring are arranged in series in the force transmission path between the drive side (1) and the power take-off side (26) of the clutch. The engagement lock (2, 8, 9, 11, 12) is stressed by a second spring which, when the engagement lock has been disengaged, acts on a first portion of the adjustment travel only. Assigned to the locking device (9) of the engagement lock (2, 8, 9, 11, 12) is an ascending curve, the steepness of which is greater over the first portion of the adjustment travel than over the portion adjoining the latter. In this clutch, the limiting torque is determined solely by the second spring.

Abstract: This invention describes a clutch device with automatic disengagement in case of overloading, useful especially for the rear power take-offs of agricultural tractors, which can be inserted in a conventional clutch casing, replacing the flywheel and the mechnical clutch of the power take-off, in which means exist for commanding the automatic disengagement of the clutch by detecting variations in magnetic flux which occur in the case of slip between the rotor and the armature of the clutch.

Abstract: A door operated drive assembly comprising an electric drive motor mechanically connected to a door pulling device by a transmission in the form of a belt drive or the like, utilizes an extension of a plate that is swingable in response to deviations of application pressure of the drive belt on belt guide pulleys carried thereby to trigger a switching arrangement utilized to trigger stopping or reversal of the drive motor. In order to make actuation of the switching arrangement a function of the degree of pressure applied by the drive belt, the plate is elastically loaded toward a middle position of its range of swingable movement. The elastic loading of the plate in accordance with a first embodiment is by way of two-arm springs positioned at opposite sides thereof, and in a second embodiment is produced by helical springs which act via actuators, on opposite sides of the plate extension.

Abstract: A power actuator for a window includes a rotary drive member and a rotary driven member which is turned by the drive member and which is connected to the sash of a window to open and close the sash as the drive member is turned in one direction or the other. A reversible electric motor drives a speed reducing gear train and the output gear of the train is coaxial with and rotatable relative to the drive member, a crank arm with a projecting pin is pivotally mounted on the drive member to swing between an active or radially projecting position and an inactive position overlying the drive member. When the arm is in the inactive position, the pin connects the output gear and the drive member so that the motor may turn the driven member. With the arm in the active position, the pin no longer couples the output gear and the drive member and the latter may be turned manually by the crank arm independently of the gear train.

Abstract: The disclosure relates to a torque responsive control system for a powered fastener driving tool having a reciprocable control rod for controlling the supply of power to the motor thereof. The torque responsive system features a plurality of ball pins that extend between front and rear ball pin retainers so as to be movable between a circumferentially extending drive position and an axially extending motor shut down position.

Abstract: The invention relates to a step drive assembly which includes a rotatable operating unit for operating a tool or knife or the like. The assembly has a change-over clutch for selectively connecting the operating unit to a continuously running motor or a brake. Control apparatus for the assembly includes a disk rotatable with the operating unit having teeth and spaces therebetween forming zones and a sensor unit for scanning the zones and outputting a pulse train. An evaluating circuit responsive to the pulse train outputs a positioned stop signal and an overload stop signal to effect a braking operation.

Abstract: A vertically movable welding and/or cutting torch is automatically disconnected from its drive when the torch bumps into a work piece.

Abstract: A clutch actuator for use in a motor driven conveyor system includes an electrical motor and a conveyor driven by the motor with a clutch interconnecting the motor and conveyor in drive relation. The clutch actuator is responsive to motor current for actuating the clutch for selectively disconnecting the motor and the conveyor. A clutch actuator actuates the clutch, for disconnecting the motor from the conveyor, when the sense current is greater than a selectively adjusted predetermined value. The clutch actuator is selectively manually actuated for actuating the clutch for disconnecting the motor from the conveyor and selectively manually actuated for actuating the clutch for connecting the motor to the conveyor.

Abstract: A fluid-operated piston is mounted on a driven shaft for joint rotation therewith and for sliding motion in its axial direction. Driven from a first drive shaft, a bevel gear is rotatably mounted on the driven shaft, while being locked against axial displacement, and held opposite to one end of the piston via a first clutch. A rotor on a second drive shaft is opposed to the other end of the piston via a second clutch. A hydraulic control circuit is provided for selective delivery of a hydraulic fluid under pressure into a pair of opposed fluid chambers in order to urge the piston into engagement with either the bevel gear or the rotor via the corresponding one of the clutches.

Abstract: A safety shut off mechanism for a fluid-powered motor comprises a reaction torque structure tending the rotate in a direction opposite to the direction of rotation of the motor under load a swing-bar for normally restraining the reaction torque structure against rotation, a reference structure for providing a point of reference as to movement of the reaction torque structure, a locking structure actuated by fluid pressure for locking the reference structure against rotation, a retaining structure tending to retain the reaction torque structure and the reference structure in a predetermined orientation relative to each other, and a shut-off structure for depriving the motor of the motive force of the fluid in response to relative movement between the reaction torque structure and the reference structure upon failure of the swing-bar.

Abstract: A pneumatic screwdriver or nutsetter includes a manually actuated electrical switch and a solenoid operated motive air shutoff valve which includes a spring biased reset element for moving the shutoff valve closure element from a valve closed position to a valve open position prior to introduction of compressed air to the tool motor. The reset element is retracted away from the closure element by pressurized air upon startup of a tool operating cycle. The closure element is released upon deenergization of the solenoid at a predetermined signal to close the shutoff valve. In an alternate embodiment the switch is replaced by a pneumatic valve and the reset element is pressure air biased to move the shutoff element from the shutoff valve closed position to the open position.

Abstract: A motor-driven piston-type valve including a valve body having a horizontally disposed fluid flow passageway. A valve piston is operatively mounted in the body for vertical movement therein to selectively close and open the passageway. An electric motor is operatively connected to the piston to vertically move the same. A slip clutch is operatively interposed between the motor and the piston whereby clutch slippage is effected when the piston encounters a predetermined resistance in its vertical movement. A limit switch is operatively connected to the clutch for triggering by clutch slippage, such limit switch also being electrically connected to the motor, whereby when the piston encounters a predetermined resistance in its vertical movement, resultant clutch slippage triggers the limit switch to stop the motor.

Abstract: An apparatus for controlling a driving force transmitted from a vehicle engine, via an electromagnetic clutch, to a compressor for a vehicle air conditioning equipment being provided with at least a sensor detecting the revolving rate of the compressor, and a clutch controller for providing a signal to disengage the electromagnetic clutch when the revolving rate of the compressor detected by the sensor is reduced below a prescribed reference revolving rate.

Abstract: This invention relates to a resettable force limiting assembly of the ball and screw type employed in a flight control actuation system. The resettable force limiting assembly includes a force transmitting reciprocating output member drivingly carried by an actuating member mounted for rotation in a housing. A reversible torque input is mechanically coupled to the actuating member to cause the output member to move in a direction dependent upon the direction of rotation of the input. A reciprocating reaction plate is secured for rotation with the actuating member. In operating cooperation with the reaction plate is a reaction plate engagement assembly that has elements secured against rotation to the housing. The elements are disposed on either side of the reaction plate. The elements have compression springs coupled thereto to resiliently separate the elements while allowing the elements to individually move towards and away from the reaction plate.

Abstract: An overload control for a mechanical press wherein excess hydraulic pressure generated by the mechanical overload of the press is applied to a transducer which develops an electrical signal which in turn is applied to a circuit which is responsive to the magnitude of the electrical signal and to the time increment during which the magnitude of the electrical signal is developed and applied to the circuit. The circuit includes a timing and reference portion comprising a voltage divider network and an RC network, and the circuit also includes a differential amplifier responsive to a difference in magnitude between the transducer signal and a signal from the timing and reference portion. As a result, when the instantaneous signal from the transducer increases suddenly due to an actual overload on the press, the circuit responds and operates a relay to cause stoppage of the press.

Abstract: A clutch type torque control device characterized in that balls seated in ball receiving holes made in a main shaft are pressed against squarely planed-off surfaces made at the outer circumferential surface of a cam fitted to a driving shaft which is driven by an air driven motor through the medium of a spring and a cam ring for transmission of motive power from the cam to the main shaft and a stop pin inserted in the main shaft is engaged with a planed-off part made at the outer circumferential surface of a pilot pin slidably inserted in the cam, whereby when a torque load on the main shaft reaches a predetermined torque value the stop pin is disengaged from said planed-off part due to rotational difference between the cam and the main shaft and consequently a valve kept open through the medium of the pilot pin and a push rod is closed, resulting in the stopping of the motor.

Abstract: In a processor of photosensitive material, a torque sensor actuates an alarm when a helical gear is subjected to torque in excess of a first predetermined value. The torque sensor includes a helical gear positioned on a shaft and biased against a stop. The gear is slidably attached to the shaft along the axis of the shaft and is fixedly attached to the shaft in an angular direction by a key. A shoulder of a flexible rubber boot movable with the gear along the shaft axis moves with the gear when the torque exceeds the first predetermined value and actuates a switch to warn the operator. In addition, as the torque increases, the gear slidably moves along the shaft past the key, thereby allowing the shaft to freely rotate in an angular direction within the gear.

Abstract: A fluid impulse torque tool used for tightening screws, which automatically stops when a predetermined tightening force is attained. A piston is actuated by relief oil from a relief valve attached to an oil pressure pulse generator. A shut-off valve placed in an air feed passageway to an air motor is connected to the piston. In a screw tightening operation, when a predetermined tightening force is attained, relief oil is produced to move the piston and this movement is transmitted to the valve to close the latter, thus shutting the air feed passageway to the air motor, so that the latter is stopped.

Abstract: A lift system for a transit vehicle includes a stationary main frame secured within a door recess of the vehicle and a side frame that is movable relative to the main frame. An articulated platform including steps pivotally secured to the side frame and scissor linkage pivotally and slideably connected to the main frame is also included. The lift system also includes a reaction switch coupled to the main frame to sense torque imparted to the main frame upon engagement of the platform with an obstacle such as a curb or the ground. If sufficient torque is created due to contact of the platform with an obstruction, the reaction switch is actuated to terminate further downward movement of the platform thereby preventing destruction of the system.

Abstract: A power operated wrench having a drive shaft, said drive shaft being initially driven by a motor to provide initial torque, overriding clutch means for driving said shaft and drive means for applying a predetermined torque via the clutch and thereafter rotating said shaft an additional predetermined amount.

Abstract: An operation control apparatus is provided of a compressor having a rotary shaft which is rotated by a driving apparatus by way of a clutch. The operation control apparatus comprises a recess or projection formed in or on one end surface of the rotary shaft as a portion-to-be-sensed offset from the axis thereof, an electromagnetic sensor disposed in facing relation with a locus described by the recess or projection according to the rotation of the rotary shaft, and a pulse monitoring circuit connected to the sensor. The sensor generates a periodic pulse signal in response to rotation of the rotary shaft. The pulse monitoring circuit generates a clutch release commanding signal to the clutch when it receives no pulse signal from the sensor for a predetermined time duration to protect the driving apparatus.

Abstract: In a motor operated hand-held tool, such as a hammer drill, a drive train transmits driving force from a motor to a drive spindle. The drive train includes a safety clutch positioned on a shaft for interrupting the transmission of driving force if a torque overload occurs. The safety clutch has a hub encircled by a gear ring with spring-biased balls releasably interengaging the hub and ring for transmitting the driving force. The hub is engaged with a thread on the shaft and under normal operation a spring prevents the hub from being rotated relative to the shaft and being displaced axially along the shaft. During torque overload conditions the hub acting against the spring moves axially along the shaft until the hub and gear ring are released.

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 dual mode valve actuator for automatically controlling the operation of a valve comprises a first reversible drive motor and a first planetary drive assembly which operate to move the valve stem axially during a first mode of operation. The actuator further comprises a second drive motor and a second planetary drive assembly which cooperate with the first planetary drive assembly to rotate the valve stem without axial movement during a second mode of operation. A control means is provided to control the operational mode of the actuator.

Abstract: Circular knitting machine for producing artificial furs or pile fabric having combed-in fibres comprises a drive motor and at least a carding device, which has a drive member being in operative connection with the drive motor for supplying rotary movement to the rotatable parts of the carding device. In order to achieve that in the event of excessive load in the rotating parts at least the operation of the carding device is automatically suspended, according to the invention there is provided between the drive motor (6) and the drive member (25) an overload clutch (23) having a device (30, 63) for automatically stopping the drive motor (6) (FIG. 2) when the overload condition is reached.

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: A door member such as a garage door is driven by a motor through a roller chain having a finite length to travel in the garage opening and closing directions. The roller chain is driven by a single drive sprocket driven by the motor to make its reciprocating movement along the same path while making rolling engagement at its roller portion with a guide rail constructed to support the roller portion of the roller chain from the opposite sides. A trolley connected to the door member by an arm is releasably coupled to the roller chain and is also guided along the guide rail while making sliding engagement therewith. A mechanism for detecting abutment of the door member with an obstruction present on the traveling path is provided to detect the above situation when a physical force is imparted to the roller chain due to the abutment. The opening and closing movement of the door member, stopping of rotation of the motor and detection of the presence of an obstruction are electrically controlled.

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: An electromagnetically operated friction clutch is disclosed of the type including an axially movable armature member which is drawn into frictional driving engagement with a friction surface on an inner body to establish drive through the clutch, in which a torque overload deenergization of the electromagnetic coil is provided. The clutch is provided with a torque boosting arrangement in which the drive from the axially movable armature is transmitted through a series of balls disposed in corresponding pockets formed in a radial face of the armature and an opposing radial face of a clutch element drivingly connected to one of the primary clutch members. The action of the balls in the pockets creates a torque boosting effect increasing the engagement pressure exerted on the frictional engagement surfaces. The torque overload release arrangement includes mounting of the clutch element axially and rotationally so as to be restrained by means of a spring element.