Abstract: The present invention relates to a fail-safe automatic sliding operation control apparatus for a press. The entrance and withdrawal behaviors of an operator's hand relative to danger zones (D, D.sub.N) on a bolster of the press are detected by an output generation configuration of two optical curtains. A signal for permitting a lowering operation of the slide is generated when the operator's hand is withdrawn from the danger zones (D, D.sub.N).

Abstract: A self-adjusting wrap spring clutch has a spring overlying driving and driven arbors and in engagement with each. One end of the spring is loosely connected to a control collar, which surrounds the spring and at least a portion of each of the arbors, while its other end is connected to the driven arbor. The control collar is held against rotation by a spring biased pawl engaging one of a plurality of preferably equiangularly spaced teeth on its circumference. When a solenoid is energized, the pawl is withdrawn from the tooth on the control collar and the spring tightens on the driving arbor to transmit torque to the driven arbor from the driving arbor. The pawl rides on a cam surface on a gear hub, which rotates whenever the driven arbor rotates, until the pawl falls into an opening or low dwell in the cam surface so that the pawl can engage one of the teeth on the control collar.

Abstract: A tube bending machine having a rotatable bend die, a pressure die, a clamp die, an actuator and a controller. A clamp assembly holds the clamp die and includes a base, a clamp die holder which is spring biased away from and slideably engageable with the base. A spacer is also attached to the base and is moveable between positions. A gear rotatably mounted to the base is attached to a first and second cam by a shaft and the gear moves on a rack. The first cam is followed by a cam follower which moves to allow the spacer to change positions. The clamp die holder may move toward the housing in case the clamp die engages an obstruction, thus avoiding damage or injury to the obstruction. A second position of the spacer substantially blocks the space between the clamp die holder and the base, thus making a substantially rigid connection between them. The second position is used during the tube bending process.

Abstract: A chuck system for machine tools with a rotating jaw chuck has clamping jaws of the jaw chuck which can be radially adjusted relative to an axis of rotation. The clamping jaws are displaceably mounted in a bearer connected with a drive shaft, and in which engagement openings for the introduction of an adjustment tool for the positioning of the clamping jaws are arranged in the region of the bearer. The bearer is surrounded by a protective sheath that is guided so as to be displaceable in the direction of the axis of rotation. The protective sheath comprises through openings, which are arranged so as to be congruent to the engagement openings in a handling position of the protective sheath, and are arranged so as to be offset to the engagement openings in an operating position of the protective sheath. In the operating position, the clamping jaws are radially surrounded, at least in regions, by the protective sheath.

Abstract: Improved redundant relay control circuits are set forth which prevent a load from being energized when any relay coil or contact or stop or start switch contact fails. A first circuit embodiment sets forth a plurality of branches with a cross-monitoring interconnection between a start branch and one of the two other circuit branches. The interconnection prevents a load from being energized when a start switch welds. Second and third circuit embodiments are configured such that the redundant control relay circuit remains inoperative until a fault is cleared although the main power across the circuit is temporarily removed. A fourth circuit embodiment operates independent of relay contact timing.

Abstract: A safety system including two command buttons (7, 8) spaced apart from one another geographically, and obliging an operator to use both his hands to control a radiology appliance, or one hand and a foot, is completed by a protocol including, on a single button (7), a short pulse followed by a long pulse during which the maneuver is carried out.

Abstract: A pressing tool for coupling elements includes a forked receiver, a clamping claw which is interchangeably held in the receiver by a connecting pin, and a drive motor for the activation of the clamping claw. The connecting pin can be inserted through holes bored in the forked receiver and the clamping claw crosswise relative to the lengthwise direction of the housing of the pressing tool. A monitoring element is provided, which checks to ensure that the connecting pin is fully inserted. The monitoring element is connected to the power source of the drive motor by means of a switching element.

Abstract: A press brake safety apparatus for use on a press brake (10) of the kind having a moving blade (18) having a leading edge (36) and a platform (38) against which an item (42) may be pressed, the safety apparatus comprising at least one beam (26) of light mounted at a level marginally forward of and substantially parallel to the leading edge (36) so as to move with the blade (18), the interruption of the or each beam (26) causing the movement of the blade (18) to stop and thereby halting operation of the press brake (10) without the leading edge (36) contacting the item (42).

Abstract: This invention describes a monitoring device which monitors the safety of a printing machine. The printing machine has a drive, a control unit arranged upstream of the drive, command buttons which are connected to the control unit and via which the start-up of the printing machine can be initiated, as well as sound generators, connected to the control unit, for the emission of an acoustic alarm signal after the actuation of one of the command buttons initiating the start-up. The monitoring device ensures that a start-up of the printing machine is only carried out if an acoustic alarm signal has previously been properly emitted. This is achieved, according to the invention, by the monitoring device registering the emission of the acoustic alarm signal and, in the event of the alarm signal not being emitted, inhibits the drive of the printing machine from starting up.

Abstract: An arrangement for collision prevention is provided for an apparatus, in particular an x-ray examination apparatus, having components that can be moved by drive means. A collision is detected by way of detecting the speed of a relevant moving part and detecting the current and/or power supply to the drive means. Reference values for current and/or power supply at normal operation in dependence of the speed acquired by moving components are provided from a memory means and actually required current and/or power supplies are compared to said reference values. In addition, actual positions of components are detected and compared to computed expected positions of said components. A collision is detected when the required current and/or power supply exceeds a relevant reference value and the detected actual position deviates from the corresponding calculated expected position.

Abstract: A safety interlock apparatus which prevents a machine from operating whenever any of the interlocking conditions are not satisfied. The apparatus provides two levels of protection, where both levels must be satisfied before permitting power to be supplied to the device. The first level is provided by a novel fiber optic switch which cannot be defeated or bypassed in normal operating situations. The switch includes a fiber optic "lock" that must be mated with an infrared "key". The second level of protection involves the monitoring of the AC voltage at the load. For interlock system to be satisfied no voltage can exist without the first level of protection also being satisfied.

Abstract: A safety guard system provided for a machine having a ram which is movable toward and away from a work zone and an actuator which is operable for driving the ram through a ram stroke toward the work zone. The safety guard system includes a safety guard mounted for movement along a guard path between open and closed positions with respect to the work zone. The safety guard is releasably coupled to the ram for movement during the ram stroke from the open to the closed position before completion of the ram stroke, and the safety guard is arranged to decouple from the ram upon either one of reaching the closed position or earlier encountering an obstruction in the guard path. A guard sensor effects a first signal upon the safety guard reaching the closed position, and an object sensor effects a second signal upon decoupling of the safety guard from the ram.

Abstract: The safety switch assembly is designed to provide a switch assembly to a tool, such as a meat slicer, in order to prevent the operation of the tool without manually holding the pressure sensitive safety handle. The assembly contains a control box having a ground fault interrupter/on-off switch, signal device, a power receptacle and a control circuit. A safety handle is installed on the tool and the handle has two pressure sensitive strips which function as a dual force sensing resistor and is connected to an electric cable that connects the safety handle to the control box which houses the control circuit. The operation of the tool requires that power be supplied to the control box. When the individual grips the safety handle and squeezes the handle, the control box provides power to the tool itself.

Abstract: A foot pedal safety switch and safety circuit for industrial machines which effectively precludes accidental operation of a machine and improper repetitive cycling of a machine. The foot pedal is completely enclosed within a rigid enclosure having an entry door through which an operator's foot is inserted each time the foot pedal switch is actuated. The safety circuit includes one or more limit switches indicating the status of the access panel and triggering a timing circuit which provides a time period within which the foot pedal switch must be contacted to operate the machine. For a second operation of the machine, the operator's foot must be removed from the enclosure allowing the access panel to close. To repeat operation of the machine, the operator then places his foot again in the foot pedal through the access panel. The safety circuit is mounted within the foot pedal switch enclosure to provide a self-contained single-actuation device which can be easily incorporated into existing machinery.

Abstract: The safety switch assembly is designed to provide a switch assembly to a tool, such as a meat slicer, in order to prevent the operation of the tool without manually holding the secondary switch and the depression of a button. The assembly contains a control box having a ground fault interrupter/on-off switch, signal device a pneumatic switch power receptacle and a control circuit. A safety handle is installed on the tool and the handle has an actuation button and a safety button, which functions as a four way valve, installed in series, and connected to an air tube that connects the safety handle to the control box pneumatic air switch. The operation of the tool requires that power be supplied to the control box. When the individual depresses the safety and squeezes the button on the handle, the control box provides power to the tool itself.

Abstract: A machine operator control station circuit which uses capacitive proximity switches to replicate the function of mechanical switches used in prior art control stations. A monitoring circuit for monitoring the "on" state of the capacitive proximity switches used in a two hand industrial machine control station is disclosed. The circuit also reduces the chance of unintended operation of the machine being controlled as a result of emitted or conducted radio frequency interference which might be detected by the capacitive proximity switches. An isolation transformer provides an isolated power supply for the monitoring circuit. The monitoring circuit includes a first capacitive proximity switch for detecting the presence of one of the machine operator's hands, and a second capacitive proximity switch for detecting the presence of the other of the machine operator's hands. Each proximity switch has a monitoring circuit for monitoring the length of time the proximity switch remains in the activated or "on" state.

Abstract: A two-hand operator's control station mounted on a common enclosure detects an operator's hands and provides output signals without requiring the operator to push buttons. Such control stations, called pushless run bars, are for use with automatic machinery which requires the simultaneous use of two hands to initiate operation of the machinery. In each embodiment of the present invention, two hand-sensing mechanisms are provided on or near the cover of an elongated enclosure, one for sensing each hand. The sensing mechanisms are located sufficiently far apart, near opposite ends of the run bar enclosure, to prevent accidental operation by one hand. Suitable anti-tie-down circuitry, an electrical cover interlock, indicator lights, and physical barriers to prevent access from certain directions may also be provided as part of the apparatus. A first embodiment of the run-bar apparatus employs two separate photo-transceiver units for detecting the operator's two hands.

Abstract: A sensing device for monitoring the presence of a tool or other object on an automatic machine comprises a sensing head adapted to be mounted on the machine. The sensing head has a sensing needle mounted on the output shaft of a reversible motor actuated on each cycle of the automatic machine for movement through a swing angle such that the sensing needle will either contact the monitored object or complete the full swing angle movement resulting in a cycle continue or cycle stop signal to the automatic machine control. The swing angle is manually adjustable by a setting ring on the sensing head for either clockwise or counterclockwise initial rotation of the sensing needle through any desired angle up to 180.degree. degrees.

Abstract: The present invention is to provide a fail-safe slide operation control device for a press of simple structure when the electronic circuit by fail-safe signal processing as a circuit for monitoring overrun and confirming the OFF condition of an operation button, which is important function to control the slide, is used instead of a contact circuit composed of relays.

Abstract: A safety control system for power operated equipment which ensures operator safety by immediately disconnecting the power drive from a power driven rotating member, such as a toothed feed shaft of a meat skinning machine or a moving blade of a band saw, and then positively stops and then reverses the direction of movement of the rotating member, upon a metal conductive glove worn by the operator, contacting the blade or toothed shaft. The operator's glove is electrically connected to a safety mechanism and upon the glove completing a circuit upon contact with the rotating member or equipment immediately disconnects the power drive from the rotating member by actuating a clutch or tensioning cylinder. A trigger mechanism then is actuated and permits a positive stopping element to engage and stop the moving element.

Abstract: In a preferred embodiment, a capacitive switch system including two capacitive switches which must be activated nearly simultaneously to operate a piece of equipment. When one switch is touched, a timing function is activated. If a predetermined length of time lapses before the other switch is touched, the other switch will be locked out. Both switches must then be released before the activation procedure is re-initiated. The components providing timed and anti-tie-down features, are integral to the circuitry of the switches and these as well as output relays are compactly housed in the switch housings to prevent tampering and circumvention of the safety features. The sensitivity of the switches is such that they cannot be activated by liquids.

Abstract: A two-hand operator's control station mounted on a common enclosure detects an operator's hands and provides output signals without requiring the operator to push buttons. Such control stations, called pushless run bars, are for use with automatic machinery which requires the simultaneous use of two hands to initiate operation of the machinery. In each embodiment of the present invention, two hand-sensing mechanisms are provided on or near the cover of an elongated enclosure, one for sensing each hand. The sensing mechanisms are located sufficiently far apart, near opposite ends of the run bar enclosure, to prevent accidental operation by one hand. Suitable anti-tie-down circuitry, an electrical cover interlock, indicator lights, and physical barriers to prevent access from certain directions may also be provided as part of the apparatus. A first embodiment of the run-bar apparatus employs two separate photo-transceiver units for detecting the operator's two hands.

Abstract: This invention provides a safety device for powered machinery comprising a conventional wire mesh safety glove adapted for wearing by the machine operator. The machine with which it is used has a grounded frame, an electrical motor, a control switch, with the electrical motor being connected to a source of electrical energy through the control switch. A control safety circuit connects the electro conducting wire mesh safety glove and by-passes the conventional control switch for the machine which is in turn connected to the motor of the machine. The safety circuit includes a circuit breaking means, preferably a relay, whereby the relay will open and deprive the motor from electrical power whenever the wire mesh glove comes in contact with the grounded frame of the machine. An alternate form of the invention connects the wire mesh glove of the operator to the antenna of a radio transmitter worn by the operator.

Abstract: A safety system for a machine tools having a powered feed table in which ultrasonic transmitters and receivers are arrayed on the leading, trailing and lateral sides of the table establishing moving protected zones so that if an operator enters the zones, the machine is shut down only if the table has moved close to the person in that zone. A failsafe feature causes shutdown in the event of failure of any of the safety system components.

Abstract: This invention provides a safety means for powered machinery comprising a conventional wire mesh safety glove adapted for wearing by the machine operator. The machine with which it is used has a grounded frame, an electrical motor, a control switch with the electrical motor being connected to a source of electrical energy through the control switch. A control safety circuit connects the electro conducting wire mesh safety glove and by-passes the conventional control switch for the machine which is in turn connected to the motor of the machine. The safety circuit includes a circuit breaking means, preferably a relay, whereby the relay will open and deprive the motor from electrical power whenever the wire mesh glove comes in contact with the grounded frame of the machine. An alternate form of the invention connects the wire mesh glove of the operator to the antenna of a radio transmitter worn by the operator.

Abstract: A safety device for an apparatus to be manipulated by an operator. The apparatus is connected via a supply line for a supply means to a supply means source. A handgrip is provided to be grasped by the operator for controlling the operation of the apparatus. An operating sensor is actuated by the operator and is connected to the control device. The operating sensor may be an electric proximity switch provided so that it is possible to shut off the apparatus when the operator ceases to actuate the operating sensor. The operating sensor, or at least one indiciator element of the operating sensor, is disposed on the hand of the operator, particularly integrated into a protective glove for the hand of the operator.

Abstract: A foot operated safety switch, preferably including an electronic control reset circuit, is connected between a source of electrical current and the power cord of an electrically operated device having an on/off switch on it. The safety switch operates as an off-only device and cannot be used to turn on the device once it has been operated to turn the device off. To reoperate the device, the on/off switch on the device first must be turned off and then turned backon. This reset necessity also is incorporated into the system to prevent the device from being automatically turned back on after it has been turned off by a power failure.

Abstract: A safety device for an apparatus to be manipulated by an operator. The apparatus is connected via a supply line for a supply means to a supply means source. A handgrip is provided to be grasped by the operator for controlling the operation of the apparatus. An operating sensor is actuated by the operator and is connected to the control device. The operating sensor may be an electric proximity switch provided so that it is possible to shut off the apparatus when the operator ceases to actuate the operating sensor. The operating sensor, or at least one indicator element of the operating sensor, is disposed on the hand of the operator, particularly integrated into a protective glove for the hand of the operator.

Abstract: An arrangement for releasably coupling an engine to a driven device such as a power tool includes a lug-bearing ring mounted on the engine, the ring encircling a centrifugally operated clutch, splined shaft or other shaft coupling member at the end of a drive shaft and having a plurality of lugs with enlarged heads mounted thereon. The engine is releasably coupled to a driven device by passing the enlarged heads of the lugs through large portions of mating apertures within a lug-receiving ring mounted on the driven device and then rotating the engine relative to the driven device to move the lugs into necked-down portions of the apertures and lock one of the lug heads against a manually actuable resilient retainer strip mounted on the opposite side of the lug-receiving ring. A cable at the end of a manually operated engine speed control on the driven device is releasably coupled to the engine throttle control.

Abstract: A system for quickly stopping the internal combustion engine of a powered implement having a deadman control normally biased toward a first position and actuable by the implement operator to a second position for normal implement operation and optionally to a third position for actuating an engine starting mechanism. The engine has a flywheel coupled thereto for rotation with the engine crankshaft and that flywheel is provided with an annular friction surface of generally cylindrical configuration disposed coaxial with the axis of rotation of the flywheel. A braking member having a second friction surface is normally biased into engagement with the flywheel friction surface and coupled to a deadman control so that the two friction surfaces will be disengaged upon movement of the deadman control to a second or operational position by the implement operator.

Abstract: A press comprising a frame with an anvil support and a punch carrier, the latter being mounted on the frame so as to be movable between two ends of travel towards and away from the anvil support. A piston and cylinder arrangement is arranged to act on the punch carrier to urge the latter in a direction towards the anvil support. That one of the two ends of travel of the punch carrier which iscloser to the anvil support is defined by a part or parts of the press itself. A limit switch is operable by means of the motion of the punch carrier, or a part connected thereto, in the said direction when the remaining available travel is a distance which is less than the thickness of an operator's finger, to enable the piston and cylinder arrangement to act on the punch carrier with a working force in the said direction up to the end of its travel.

Abstract: The object of the invention is a cubicle for machining centers, consisting of a front one or multipart face wall and stationary or multipart side walls (11, 12), which can be designed to be like sliding doors. In order to prevent damage to the side walls or the windows therein through a collision with a workpiece projecting sideways during the machining cycle or during set up, a part of the side walls (11, 12), according to the invention, is designed to swing sideways, so that it can yield way by a pre-determined distance upon impact by a workpiece. At least one emergency switch is installed in the movement range of these side wall parts, which switches off the forward drive of the workpiece table(s) (4) when it is activated.

Abstract: A safety stoppage or disconnection apparatus for mechanically moved tools, particularly automatic welding guns, having a swashplate and an assembly casing, between which are arranged one or more spring elements and a switch operated by the relative movement between the swashplate and assembly casing. It is necessary with such safety apparatuses to prevent other adverse rotary movement between the swashplate and assembly casing. This is brought about by two facing bolts, whose heads projecting beyond the outer wall of the swashplate are guided in slots, which run in the inner wall of the assembly casing in the intended swashplate movement direction. The bolts are spring-loaded and preferably spherical.

Abstract: The present invention discloses both a safety sensing system and a method of providing safety protection for presses or like industrial machines having a reciprocally movable operating head, ram, tool or beam. The basis of the system is the provision of a first beam (or a plurality of first beams) each of which is placed across and in front of the intended direction of travel of the pressing tool or blade. A second beam is arranged in the intended direction of travel and is broken by the tool or blade when the latter has reached a predetermined minimum height above a workpiece. A control system is provided which, during the operating stroke of the blade retracts the blade if any one or more of the first beam(s) is or are broken but the second beam is not broken. However, once the second beam is broken, the stroke of the blade is completed even if the first beam(s) is or are broken, for example, by folding of a pressed workpiece.

Abstract: A continuously running mechanical transfer press includes a workpiece transfer system in which electric motors are used to provide reciprocating movements in the clamp, lift and transfer axes. An independent backup tracking system including a fault detection sensing control is provided which utilizes independent measures of the position of the workpiece transfer system in all three axes along with an independent measure of the position of the press die in its cycle to monitor proper synchronization and operation of the workpiece transfer system. The fault detection system indicates a fault in the event the transfer system loses synchronization with the moving die, in the event two separate measures of die position are not in agreement, or in the event the transfer system fails to maintain parallelism of the two transfer rails included in the system. The press is stopped in response to detection of a fault to protect the press and the transfer system from damage.

Abstract: To permit operation of the power tool only if both hands of an operator are engaged, the tool is formed with a handle portion which has a sensing surface thereon, electrically coupled to a current flow sensing circuit, preferably including an opto-coupler or a field-effect transistor (FET) circuit which permits firing of a triac, thyristor, or the like only if current flows over the sensing surface by area contact therewith. The sensing surface is energized, preferably, from a resistive or capacitative voltage divider; the capacitative voltage divider has the advantage that the triac firing circuit can cause the triac to fire during null or zero crossings of ac supplied power. If a locking-type switch is used, two handles or touch-areas are needed; if a spring-loaded switch is provided, it can function as one safety element, and a touch-area sensing surface as the other.

Abstract: A slide stop position control apparatus of a press machine which can automatically effect slide stop position adjustment when the die and/or the punch are changed. The apparatus comprises a first detector for detecting the tip of the punch and a second detector for detecting an upper end of the die when the slide is moved towards the die. The first detector is mounted to a die base and the second detector is mounted to the slide and each detector includes a light emitter and a light receiver. A slide position detector is also provided and all of the detectors are connected to a control unit for controlling a drive unit for the slide.

Abstract: An apparatus is provided for machining tubular and/or rod-shaped workpieces. The apparatus has a rotational drive or motor for the workpieces to be machined. A switching device, which is accommodated in, and actuated by, a foot pedal, is connected to the rotational drive. The foot pedal is provided with a restart arrestor, and/or an emergency shutoff device to provide protection against unintended restarting of the apparatus after a power failure, or to instantaneously disconnect the apparatus from the electric circuit in case of danger.

Abstract: A guard for protecting the hand or hands of an operator to limit the extension thereof and prevent entry into a hazardous or danger zone of a machine, such as a stamping press or the like, includes a shield in the form of a transparent or partially transparent rigid plate member which is fixed in spaced relation to the throat or nip point or hazardous region of the press. The plate has an aperture through which the operator may extend a portion of a protective glove in loading and unloading articles into and out of the hazardous region. The glove has a rigid, radially extending cuff or collar surrounding the glove at the wrist portion and having an outer dimension which exceeds that of the aperture formed in the plate. The position of the collar on the glove is related to the position of the plate and the maximum extension of the fingers such that when the glove is inserted through the opening, no part of the hand may enter a predetermined danger zone.

Abstract: A method of and apparatus for controlling the movement of a workpiece to be processed in a punch press is disclosed in which after the workpiece is processed by contact of a ram on the upper tool of the press and the ram is momentarily out of contact with the upper tool, the recontact of the ram and upper tool is detected and then the processed workpiece is moved out of the processing position. In addition, the apparatus detects when the ram has returned to the proximity of the top dead center of the eccentric shaft which drives the ram and when the processing of the workpiece has been completed. The apparatus is also provided with a monitoring system which detects a malfunction in the control apparatus.

Abstract: A control device for a small press is provided with means preventing overloading of the drive motor, a timer for detecting when an operational cycle of the press has exceeded a normal value, and a position detector which notes the position of a cam of the press. The power switch of the drive motor is tripped to suspend the flow of current to the motor upon an indication of the foregoing, e.g., a detected over-current, an excessive cycle time, or an operation end position of the cam.

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 safety mat for a power driven machine which stops or prevents operation of the machine when a person is standing on the mat. The mat has at least one supporting plate held in an unloaded position by springs and actuating at least two limit switches when depressed as by a person stepping on the mat. The limit switches are part of a safety circuit interlocking a main circuit for disabling operation of the machine when at least one of the switches is actuated. The switches selectively energize relays having contacts which energize an output relay for opening or closing the circuit to be opened for safety reasons on the machine. The relays also have contacts which energize a timer relay when the safety mat is depressed as by a person stepping on the mat. The timer relay energizes a timer switch and this provides a self-checking function whereby if there is a defective component in the system the timer relay will not be energized and the main circuit will remain disabled.

Abstract: A machine control system for sensing an obstruction in the path of a machine tool and preventing movement of the tool along its path while requiring operator initiation for each machine tool actuation. A sensor is mounted on a movable support rod and adjustably positioned to move along a path coaxial with the path of the tool in order to sense any obstruction in a work area. The movable support rod is constructed to allow gravity fall of the sensor into the work area and to cause actuation of a switching circuit allowing machine tool movement if no obstructions are sensed. A spring-biased arm coupled to a rotary solenoid retains the movable support rod in a rest position. Upon actuation, the solenoid rotates the arm so that gravity causes the support rod to fall and the sensor to move into the work area. A normally closed switch is positioned to open in response to the end stroke of machine tool movement.

Abstract: A safety control system for a metal forming machine having a vertically moving forming ram which cooperates with a stationary forming die for forming a variety of creases in sheet metal manipulated by an operator. The safety control system returns the forming ram to an inactive position in the event the operator inadvertently positions tool or limb between ram and die during machine operation.

Abstract: Accident prevention apparatus for mounting on a machine, tractor or other apparatus having at least one moving part driven by a power source. The accident prevention apparatus comprises, in electrical circuit, an elongate contact-sensitive antenna, movement-sensitive means and means including a solenoid to cut off power from the power source.The movement-sensitive means includes a mounting and a plate spaced apart and insulated from each other, the antenna being rooted to the mounting to extend therefrom through a hole in the plate and therebeyond to extend in the vicinity of the moving part. Contact with the antenna by the operator's clothing causes it to touch the plate which actuates the solenoid to cut off the power to the machine or to the moving part of the machine.

Abstract: A control circuit for a press can perform various control functions simply by electrically detecting two modes of change, i.e. from OFF to ON and from ON to OFF, of a single rotary cam switch mounted on a press. Until reaching a first slide stroke angle at which the first change of the rotary cam switch takes place, operation of the press depends upon an ON or OFF state of a push button and thereafter the operation continues regardless of the ON-OFF state of the push button. After reaching a second slide stroke angle at which the second change of the rotary cam switch takes place, the operation of the press is stopped with the slide being stopped at a top dead center regardless of depression or non-depression of the push button and restarting of the press function is prevented in case the push button is kept depressed.

Abstract: An improvement is disclosed for a machine of the type having a main drive which may be activated to move a ram with a high force against a workpiece. The improvement is a safety device which includes an apparatus in addition to the main drive for moving the ram to a position near the workpiece with a low force capable of being stopped by contact with a part of the human body. Further apparatus is provided that allows the main drive to become activated only when the ram is within a preselected distance of the workpiece. As a result, the distance can be selected to be smaller than, say, a finger, so that the presence of a finger between the ram and a workpiece will prevent the ram from being driven at a high force.

Abstract: An alarm circuit is interlocked with the start circuit of power driven industrial machinery such as a coal tipple so that before the machinery can be started, an alarm must be energized for a predetermined time to alert personnel that the machine is about to start. In the event that the machinery is not started within a predetermined time after termination of the alarm, or in the event that the alarm has not actually sounded, the whole cycle must be repeated.

Abstract: An electric motor-driven sewing machine which includes a drive mechanism for driving the machine by an electric motor, a mechanism for stopping operation of the machine by a brake, an automatic thread trimmer mechanism, a wiper mechanism for removing the trimmed thread, command switches for providing command signals to the sewing machine and control circuit means for controlling the various operations of the sewing machine in accordance with electrical signals. Apparatus is provided for detecting an abnormal state in which input signals which are not to take place simultaneously occur simultaneously, and to invalidate the operations of the various mechanisms of the sewing machine to protect the user from danger due to erroneous operations of the sewing machine.