Abstract: A power drive screwdriver that is constructed to automatically stop when a predetermined torque is reached. The screwdriver includes a housing having a pneumatically driven motor therein and an output shaft that is linked to the screwdriver bit through a releasable clutch. A control valve is positioned in the housing to control air flow to the motor. The position of the valve is controlled by a rod that extends through the shaft. A transverse slot extends through the shaft intersecting the bore therein and the transverse slot contains a pair of balls that are retained within the slot by a sleeve encircling the exterior of the shaft. Further, a reset member engages the screwdriver bit and also engages the balls to displace the balls in the slot in a direction to open the valve. When the predetermined torque is encountered, the sleeve moves upwardly, permitting the balls to separate and thereby letting the valve rod move to permit the valve to close.

Abstract: A screw driving apparatus has a housing (1) for the drive system and a hollow screw guide member (2) rigidly secured to the housing (1). A screw driver blade (5) is axially displaceable in the hollow screw guide member and relative to a drive motor forming part of the drive system. This arrangement of the components results in a compact short structure with a handle located near the center of gravity of the structure. Hence, the apparatus can be operated by one hand only and an operator has his other hand free, for example, to hold a work piece (7).

Abstract: A control system for power tongs comprises two tongs torque limiters, one of which limits tongs torque to a very low (hand-tight) level; the other limits torque at full makeup to, for example, 2000 ft. lb. The hand-tight torque limiter is manually or automatically disabled after the hand-tight level is reached. The system enables the operator to verify that the threads are properly engaged before applying full torque to the connection. The tongs have a very high reduction ratio, so that torque rises very slowly and can be more accurately controlled.

Abstract: The power tongs control system described herein includes a hydraulic load transducer in the tongs snub line, the transducer output controlling a shunt valve between the hydraulic lines leading to and from the tongs drive motor. At a predetermined threshold tongs torque, a switch is actuated by contact with a Bourdon tube connected to the transducer output closure of the switch causing the solenoid actuator to open the shunt valve and thereby halt operation of the tongs. A timer is provided to maintain the tongs in the disabled configuration for a period of time following initial cut off. Also disclosed is an adjustable choke valve in series with the shunt valve so that even following the opening of the shunt valve, substantial torque is maintained upon the pipe by the tongs.

Abstract: A pneumatic power tool for tightening screw joints includes a primary motor 11 for a high speed running down sequence, a secondary motor 12 for a high torque final tightening sequence, a coupling gearing 18 providing a high ratio gearing for the secondary motor 12, a gearing of a substantially lower ratio for the primary motor 11 and a one-way clutch 30 by which the secondary motor 12 is automatically engaged at decreasing tightening speed. An air supply valve 33 substantially reduces the air consumption of the tool by keeping the air supply to the secondary motor 12 shut off until a certain degree of tightness in the joint is obtained, after which the valve 33 is opened and the secondary motor 12 is energized.

Abstract: There is disclosed and shown an automatic nut installation and torquing system (10) connected with an automatic fastener installation machine (11) whereby a threaded nut (21) is automatically conveyed in proper orientation from a supply source to a final installed position on a threaded fastener (34); the installed nut (21) being at a selectively predetermined final torque value that is selectively variably and controllable without regard to the torque output of the torque motor (48) so long as the desired installed torque value of the nut (21) does not exceed the maximum torque deliverable by the torque motor (48). The variability and controllability of installed torque is accomplishable without any recalibration or readjustment of torque motor (48) to change its torque output.

Abstract: A pneumatic power tool for tightening screw joints includes a primary motor 11 for the high speed running down sequence and a secondary motor 12 for the high torque final tightening sequence. The tool includes a coupling gearing 18 providing a high ratio gearing for the secondary motor 12, a gearing of a substantially lower ratio for the primary motor 11 and a one-way clutch 30 by which the secondary motor 12 is automatically engaged at decreasing tightening speed. An air supply valve 33 is employed to substantially reduce the air consumption of the tool by keeping the air supply to the secondary motor 12 shut off until a certain degree of tightness in the joint is obtained, after the valve 33 is opened and the secondary motor 12 is energized.A reduction gearing 19 is supported in a casing 90 which is rotatively connected to the tool housing 10 and provided with a laterally extending torque reaction bar 92.

Abstract: The invention relates to a compressed-air screwdriver including a tool spindle, displacable against the action of a spring; an automatic shutoff having a valve for the motor, which upon attaining a predetermined torque is turned off and a device whose actuation, after the automatic shutoff, permits the motor to be put back into operation so that a screw can be further tightened or loosened with increased torque.

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: Screw clamp pin extractor for clamping pins of the type having a body fastened to a spreader lying between two tongs secured to a screw, and a nut acting against a spring. The extractor comprises a pneumatic motor, a nose portion engaging the clamp pin and carrying a sleeve brought into contact with an assembly of sheets, said extractor comprising moreover an internal mechanical system. When the motor rotates for unscrewing pins the device is locked on the pin and the nut of same can be unscrewed, and thereafter, the pin is extracted through the action of a jack. The extractor can be attached as desired either to the body of the usual manual screwing machine or a robotic head known in itself.

Abstract: An apparatus for measuring mechanical strain in a bolt, stud or other tensile member includes a measuring rod which is held in a fixed position with respect to a selected point in an axial bore in the tensile member being measured. A bolt extension tube extends into the axial bore to provide a wrench support function and is held in a fixed position with respect to a second point on the tensile member. Straining the tensile member results in a relative displacement between the rod and the tube which is proportional to tensile member elongation. Means are provided for setting a preselected strain, measuring strain, displaying strain and providing a control signal to control straining of the tensile member.

Abstract: An automatic, push-to-start, fluid-operated screwdriver is disclosed including a magazine providing a supply of fasteners so that only a source of fluid pressure is required for operation. A control valve is responsive to push-to-start actuation for automatically initiating a series of steps including (a) commencing operation of a fluid operated motor, (b) terminating operation of the motor when a predetermined torque level is applied to the fastener, (c) causing a subsequent fastener to be released from the magazine, (d) relatively shifting a fastener holder and rotary drive means for allowing the subsequent fastener to enter into alignment with the rotary drive means, (e) causing the holder to secure the fastener in engagement with the rotary drive means, and (f) thereafter returning to the condition prior to step (a) so that the machine is automatically conditioned for driving the subsequent fastener upon push-to-start actuation.

Abstract: A portable fastening tool of the type incorporating torque and angle sensors is connected to a data processor which analyzes the torque and angle sensings and generates a shut off signal to terminate tightening. The tool is powered and includes a fluid motor typically energized from a remote source of high pressure air. The data processor is energized by either a battery or an AC source. Termination of tool operation is effected by energizing a solenoid in response to a shut off signal generated by the data processor. In a battery operated embodiment, tool operation is initiated by manual depression of an operating lever while tool termination is effected automatically in response to the shut off signal. This mode of operation reduces the number of required batteries, prolongs battery life and reduces the number and size of electrical components in the tool.

Abstract: A screw tightening apparatus comprises a motor-driven screwdriver bit supported on a base for tightening a screw with a torque which is detected as a reactive force acting on the base by a torque detector. An output signal from the torque detector is amplified and delivered to a comparator in which the signal is compared with a signal from a torque setting device which is indicative of a desired torque with which the screw is to be tightened. When the signals agree with each other in the comparator, the latter produces an output signal which is supplied to a switch which in turnde-energizes an electric or pneumatic motor of the screw tightening apparatus. An adjustable time-delay circuit is connected between the comparator and the switch to delay the signal from the comparator for a period of time which may be varied dependent on the material into which the screw is to be driven and the pitch and material of the screw in use.

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: The invention relates to a control apparatus for a pneumatic impact wrench driven by an air motor.

Abstract: A portable pneumatic tool includes a valve closure member interposed in the tool motor exhaust passage and engaged with a speed responsive mechanism comprising a plurality of flyweights operable to move the closure member to an open position on starting of the tool motor. On decreasing motor speed a coil spring assisted by a fluid pressure drop across the closure member forces the closure member to move against the decreasing centrifugal force exerted by the flyweights to shut off motor exhaust fluid flow to stop the motor. The closure member is normally held in a partially open position by a second spring to enable the motor to be started. An alternate embodiment includes a limited motion coupling between the valve closure member and the motor drive shaft which provides assistance in opening and closing the valve closure member.

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 pressure air on 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: The improved shut-off apparatus for pneumatically driven tools includes an auxiliary shut-off valve located in the flow passageway. The valve is controlled by a control rod which extends through the air motor into engagement with a latching device. The latching device is held in the latched position with the valve open by a movable weighted control member. The movable weighted control member is responsive to inertia so that as the speed of the air motor decreases due to a torque load imposed thereon, the shaft slows causing the inertial movement of the weighted member to release the latching device permitting the auxiliary shut-off valve to close.

Abstract: Apparatus for recording and limiting the torque applied to a pipe by a set of power tongs, wherein the tongs are operated by a hydraulic fluid pumped through a feed line to a hydraulic motor in the tongs and then returned by a return line. The apparatus includes a hydraulic tension cell attached between the tongs and a fixed attachment whereby torque applied by the tongs causes hydraulic pressure in the tension cell proportional to the torque applied. The tension cell is hydraulically connected to a helical pressure sensor tube. An operating arm is attached to the pressure sensor tube such that hydraulic pressure in the hydraulic tension cell causes the operating arm to rotate in an amount proportional to the pressure and therefore the torque. The operating arm is cammingly engaged with a spring arm which in turn is engaged with an air valve.

Abstract: There is disclosed a technique for tightening threaded fasteners in which values of offset torque, initial tension rate relative to angle, final tension rate relative to angle and other joint related factors are empirically determined by instrumenting a plurality of fasteners of the type ultimately to be tightened. In one embodiment, torque and angle are monitored during tightening. Calculations are conducted, while tightening, to determine the tension prevailing in the bolt at a particular angle of advance. By using the calculated tension value and the particular angle of advance, an instantaneous position of threading advance on the tension-angle curve of the fastener is established. From this instantaneous position, it is determined how much greater angle of advance or how much torque is required to tighten the fasteners to a final desired tension value. The same technique may also be used merely to monitor tightening which is terminated by a different tightening strategy.

Abstract: An impending kickback condition is the operation of a power tool or machine tool system is sensed and used to control or eliminate the kickback. The ability to sense an impending kickback condition can be used in all categories of power driven tools. The change in force applied to the power driven tool or other implement is monitored by measuring the rate of change of speed of the tool or implement, and if the speed is decreasing, the rate of change of speed is compared with a threshold value which may be either preset or variable. If this threshold value is exceeded, an output control signal is generated which inhibits the coupling of power to the tool or other implement and/or applies a brake to stop the tool or implement. In order for power to once again be coupled from the motive power source to the shaft, the start switch must be opened and then reclosed or some other signal provided by the operator or another predetermined condition must be met.