Abstract: A technique reduces an increase in the size of an impact tool. An impact tool includes a motor, a striker drivable by the motor, an anvil including an anvil shaft to receive a tip tool, and an anvil projection protruding radially outward from a rear end of the anvil shaft to be struck by the striker in a rotation direction, a hammer case accommodating the striker, a bearing held in the hammer case and surrounding the anvil shaft, a ring member at least partially facing a front surface of the anvil projection and in contact with a rear end face of the bearing, and a stopper engaging with the hammer case and the ring member to reduce moving of the ring member rearward.

Abstract: A hydraulic system and a method comprising a linear actuator 23 for generating discrete sum forces, chambers A-D for generating discrete force components, at least two charging circuits 3,4 configured to maintain predetermined pressure levels of hydraulic fluid, independent control interfaces 9-16 configured to open and close connections of the first and second charging circuits to the chambers, and an electronic control unit 50 for controlling the control interfaces. At least two control interfaces are proportional valves which are used as shut-off valves and are independently switchable to the open and closed positions in a controlled manner. Moreover, non-throttled control and secondary control are implemented in the hydraulic system and the method.

Abstract: The hydraulic source control device includes an operation input device capable of inputting operation conditions regarding the driving force of a fluid pressure control element, a servo motor including a motor section that drives a hydraulic pump and an amplifier that drives the motor section, and a controller that outputs a control command to the servo motor based on an input result to the operation input device. The controller obtains the fluid pressure of a working fluid based on the operation conditions regarding the input driving force, computes the output torque of the motor section based on the relationship between the fluid pressure and the output torque that are stored in advance, and outputs the computed output torque to the amplifier as a control command of the torque limitation value of the servo motor.

Abstract: A method and a pressurized medium system, including: at least one actuator to generate sum forces effective on a load; a working chamber operating by displacement and located in the actuator; a charging circuit of a higher pressure, which is a source of hydraulic power; a charging circuit of a lower pressure, which is a source of hydraulic power; a control circuit, that couples the charging circuit of higher pressure and the charging circuit of lower pressure, in turn, to the working chamber; wherein the working chamber is capable of generating force components that correspond to the pressure of the charging circuit to be coupled to the working chamber, and each force component produces at least one of the sum forces either alone or in combination with the force components produced by the other working chambers of the actuator.

Abstract: A device for adjusting the stroke volume of a first piston engine (1), having a bent-axis design, and a second piston engine (2), having a bent-axis design, and a common component (4) by which the stroke volumes can be adjusted. A valve (12) is provided which, when a maximum pressure level in the working lines (3) is exceeded, the valve (12) is reversed such that the common component (4) reverses the stroke volumes toward a lower power consumption arrangement.

Abstract: Apparatus and methods are provided for controlling a double-acting hydraulic cylinder during a load-induced rod-extending operation, where the cylinder is activated by fluid supplied from a reservoir by a pump, and the cylinder has a rod end, a head end, a piston connected to a rod for engaging the load, the cylinder piston being urged toward the rod end by the load during the operation.

Abstract: Provision of a fail-safe circuit which is capable of allowing a sub circuit to operate with reliability when a main circuit encounters abnormal conditions even in a system with only one supply source of pressure oil. A plurality of solenoid type control valves (3, 6) connected to an actuator (1) in parallel have centering springs respectively and are maintained at a neutral position in normal conditions. Each control valve is provided with a supply port, a return port and two actuator ports and is configured such that in the neutral position, the supply port and the return port are communicated with each other and interrupts communication with the actuator ports.

Abstract: A fluid pressure control system for limiting the torque output of a positive displacement hydraulic motor (21) for rotating a screw anchor (11, 11′) into the ground. A normally closed solenoid operated control valve (76) is mounted in a bypass line (86) between the high pressure supply line (30) and the low pressure exhaust line (36). A plurality of electro-hydraulic switches (72) are arranged for setting at different predetermined fluid pressures and are in fluid communication with a differential pressure sensing chamber (63). Upon turning on of a selected switch (72) having the desired pressure level, the reaching of the desired pressure level activates the selected switch (72) for actuation of solenoid operated control valve (76) to move control valve (76) to an open position as shown in FIG. 3 to bypass fluid from high pressure line (30) to exhaust line (36) to limit the torque output of the motor (21).

Abstract: A screwdriving spindle assembly comprising a spindle shaft provided with a holding device and secured to a gear wheel rotated by a drive assembly which comprises a pressurized fluid actuating cylinder having a piston rod secured to a transmission system, and a member for adjusting pressure disposed on a line for feeding fluid to the cylinder in the screw-tightening direction.

Abstract: Method for controlling a pressurized fluid-actuated double acting cylinder in an assembly such as a hydraulic tightening spanner (1) with a control unit therefor, wherein a piston (5) may be reciprocated repeatedly, firstly with an active stroke providing a desired maximum force, and then with an opposed passive stroke returning the piston (5) to its starting point to enable repetition, and wherein said method comprises selecting a set fluid pressure corresponding to the desired maximum force (Fr) and measuring the time elapsed (Te) between the beginning and the end of the passive return stroke to determine that the force has been achieved. A device for implementing the force is also disclosed.

Abstract: An auto cycle pump in accordance with the invention includes a housing having a reservoir for storing hydraulic fluid. A hydraulic pump in the housing provides hydraulic flow. A directional valve has neutral, advance and retract positions to respectively restrict hydraulic flow, direct hydraulic flow to an advance port and direct hydraulic flow to a retract port, the ports for hydraulic connection to the hydraulic tool, in use. Fluid conduits are provided connecting the pump and reservoir to the directional valve. A flow switch detects return flow from the directional valve to the reservoir. A pressure sensor sense hydraulic pressure from the pump. A dump valve is operatively connected to the pump for directing hydraulic flow back to the reservoir when the directional valve is in the neutral position. A control is operatively connected to the pump, the directional valve, the flow switch and the pressure sensing means for controlling operation of the auto cycle pump in automatic mode of operation.

Abstract: Compressed air is introduced into a cylinder chamber to displace a piston closely to a target position. Then, a ball screw shaft is rotated about its own axis by an electric motor to inch the piston to the target position. Upon arrival of the piston at the target position, the ball screw shaft is stopped by a brake mechanism to hold the piston accurately in the target position. The drive shaft of the electric motor extends parallel to the ball screw shaft, thus reducing the entire length of a servo cylinder apparatus. Solenoid-operated directional control valves, for supplying compressed air to the cylinder chamber and the brake mechanism are coupled integrally to a cylinder assembly, so that pipes are shortened for allowing the piston to be displaced and stopped quickly and accurately.

Abstract: A torque controller which limits the output of a hydraulic motor is provided. The torque controller includes a by-pass circuit which allows the hydraulic fluid in the hydraulic fluid circuit to by-pass the motor. A valve manifold is placed in the by-pass and includes a main chamber having a main valve member and one (and preferably two or more) poppet valves in communication with the main chamber. The pressure at which the poppet valves and the main valve open are individually adjustable and are set for different pressures. Inlets to the poppet valves are closed with electrically operated solenoids such that the inlet to a selected poppet valve can be opened to activate that poppet valve.

Abstract: This invention is intended to effect torque control of high accuracy by detecting the oil pressure at the time of the generation of a pulse which forms the basis of the generated torque for a torque wrench and using the data thus obtained the effect torque control. Oil pressure pulses generated in a pulse generating mechanism 3 by the rotation of an air motor 1 are transmitted to a hydraulic cylinder 4 by a piston 33, a rod 36 and a piston 35. In addition, a pressure sensor 5 installed in the hydraulic cylinder 34 detects the oil pressure pulses and its signal is used to switch a switching valve 7, whereupon a stopping switching valve 9 and a stopping differential pressure valve 8 are successively switched, stopping the feeding of air to the air motor 1 while cutting of the passage of electric current from a battery 61 to an electric control circuit 6.

Abstract: An air tool torque control system includes a controller operative to independently control two air tools with continuous programmed adjustment of the torque shut off point for each tool after each fastener joint is made. The torque specification is measured for each fastener joint made, is verified as being within an acceptable torque range, is compared to the set point of that torque specification range to determine the variation therebetween, and is then adjusted toward the mid point by the applicable correction factor for the variation determined to continuously compensate for variations in joint rate, line pressure and/or tool output. To enhance the effectiveness of the system, fast acting solenoid valves utilizing line pressure to assist in valve closure may be included to improve shut off control.

Abstract: A hydro-impulse screwing device comprises a rotary drive motor, a power source for the motor, a drive shaft, a pulsating hydraulic drive connecting the motor to the shaft and a power cut-off for the motor. The load at which the power cut-off functions is adjustable. The tool has a borehole extending through the length of the shaft, a conduit for conducting hydraulic fluid from the drive to the borehole, a valve in the borehole movable from a closed position to an open position in response to hydraulic pressure corresponding to a predetermined load to allow hydraulic pressure from the drive to actuate the power cut-off, a biassing element in the borehole for biassing the valve toward a closed position against the hydraulic pressure, wherein the force of the biassing element is adjusted at the end of the drive shaft to change the load at which the power cut-off operates.

Abstract: A stroke control device having a servomotor, a hydraulic cylinder having a piston, a ball-thread mechanism coupling the servomotor with the piston, and a hydraulic circuit including pressure control valves for driving the hydraulic cylinder. Further it has a numerical control unit for driving the servomotor based on the numerical input data representative of the movement and moving speed of the piston, for detecting signals representative of the load on the servomotor and for producing control signals to control the pressure control valves in the hydraulic circuit in response to the load signals to move the piston so that the load on the servomotor will approach zero.

Abstract: The air tool of the present invention includes a torque shut-off valve totally enclosed within and substantially coaxial with the body housing of the tool. The torque shut-off valve includes a valve member reciprocally sliding in and guided by a bore and counterbore in the valve body. The valve member is biased by a reset spring to its open position before the tool cycle is initiated. In operation, the valve member is axially biased toward its open position by supply line air pressure in an air inlet chamber in conjunction with controlled reduced air pressure in an associated compartment and is axially biased toward the closed position by motor inlet pressure. A preselected motor back pressure resulting from achieving the desired tool torque operates to overcome the opposing pressure to close the valve member to block air flow to the motor.

Abstract: A fluid-actuated shut-off valve for a fluid-powered tool such as a wrench including a spool valve urged to open position by a spring and having respective valve-operating surfaces subject to both regulated inlet and exhaust pressures in the tool. The valve operating surfaces and spring are arranged so the valve is thrown to its closed position by a combination of a constant regulated control pressure and the drop in exhaust pressure as the tool motor slows down and stalls under load. The valve operating mechanism also includes an element for preventing high pressure fluid from venting to the workplace during motor stall.

Abstract: An impulse tool has an air motor connected to rotate a housing that carries a spindle adapted to be connected to a tool. The housing and cavity provide a pulsating force for rotating the spindle and tool to a pre-selected torque limit. When the limit is reached a rod in the housing is moved rearwardly to contact an "L" shaped arm. The "L" shaped arm is moved to release a valve assembly that operates to close off the air supply to the air motor and thereby turn off the tool.

Abstract: In a blind riveting apparatus for rivets of different sizes, with a compressed air feed line and an actuating means controllable by the compressed air, and a rotary motor, provided at the inlet (6) of the compressed air feed means (9) into the blind riveting apparatus (1) is a means (10) for setting the level of the pressure of the compressed air which flows into the apparatus (1).

Abstract: The present invention relates to a device for shutting off a supply of pressurized motive fluid to an associated fluid driven motor in response to a predetermined motor back pressure indicating a predetermined load on the motor. The device comprises a housing having a fluid inlet connected to a supply of motive fluid and a fluid outlet connected to supply pressurized fluid to the associated fluid driven motor. A passageway extends through the housing between the fluid inlet and the fluid outlet. A shut-off piston is slidably mounted with the housing and is shiftable to close the housing passageway and shut off the supply of pressurized fluid to the motor in response to a predetermined motor back pressure. An orifice of variable size is provided in the housing passageway and is utilized to reduce the pressure of the fluid supplied to the motor.

Abstract: A pneumatic throttle control configuration provides synchronized start-up and independent shut-off of multiple pneumatic tools. Each tool includes a throttle control assembly having a manually operable throttle valve which selectively admits air to the vane motor of the tool and a spring-biased piston operably coupled to the throttle valve which maintains it in an open position in response to air pressure in a control line which interconnects the tools. The vane motor includes a governor controlled valve which opens at a predetermined motor speed and provides air to the control line and the pistons of each tool of the multiple tool arrangement, thereby opening every throttle valve. Each pneumatic tool may then operate and stall independently. When the last tool stalls, the control air flow to all tools is terminated and the throttle valves close.

Abstract: In a pneumatically powered rotating grinding machine there is provided a safety unit (13) comprising a speed governor and an overspeed release mechanism the purpose of which is to ensure a predetermined maximum speed. For safety reasons, the motor speed must never exceed a certain critical speed level which is determined by the mechanical strength of the working tool attached to the machine. When choosing a working tool to be attached to the machine the maximum speed mark of the machine is decisive. By having a portion of the safety unit exposed through an aperture (57) in the tool housing (10) and having the maximum speed mark (52) of the safety unit (13) located at the exposed portion, the maximum speed mark of the machine will always be the same as that of the safety unit (13). The suggested overspeed safety device avoids the risk involved in the event that a machine carrying a certain maximum speed mark might be erroneously fitted with a safety unit (13) intended for a higher maximum speed.

Abstract: The air tool of this invention features a shut-off valve in a motor inlet passage with an air bias compartment at one end of the valve and a motor pressure compartment at an opposite end of the valve directly communicating with the inlet to the motor. The air bias compartment has adjustable air bleed means for selectively reducing the pressure in the air bias compartment from a predetermined line pressure to a desired operating pressure at a constant percentage less than the predetermined line pressure. To establish the predetermined line pressure of the air supplied to the motor and to the air bias compartment of the shut-off valve, a stall torque regulator is provided upstream of the shut-off valve. This regulator serves to maximize the flexibility of the tool by providing for the adjustment of the tool to a given range of pressure and torque at which the motor will shut off but without undesirably affecting the free running speed of the motor within that given range.

Abstract: A valve driving apparatus comprising a case proper provided in the interior thereof with a movement conversion-transmission mechanism, a cylinder mechanism freely detachably fixed to one end of the case proper and a piston rod supporting mechanism freely detachably fixed to the other end of the case proper so as to be applicable to any kind of valve merely by the replacement of the mechanisms between which the case proper intervenes.

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: A torque control for a fluid operated motor includes a first gear to be driven through operation of the motor and a second gear in driving engagement with said motor and maintained in a generally stationary position during normal operation thereof. The torque control further includes a drive mechanism connected to the first gear and to a load to be rotationally driven through operation of the motor. A valve is provided in the fluid supply to the motor to open and close the supply of fluid thereto. Disconnect means is operatively connected to the second gear and the valve to maintain said valve in an open position to permit supply of fluid to said motor when the second gear is stationary. The second gear rotates when the torque required from the motor to rotate the load exceeds a predetermined magnitude to move the disconnect means relative to the valve to close the valve to terminate the supply of fluid to the motor.

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: A rotary power driver is provided which drives with a two-stage torque and speed control, wherein the initial driving is done at higher speed and lower torque, and a subsequent higher torque is automatically imposed with lower speed. The second stage is a selected pre-set stage, with provision for the selected torque built into the driver. The second stage is imposed on the drive shaft by a one-way clutch or ratchet drive.

Abstract: A compressed-air dental motor includes a housing, a rotor, a compressed air inlet conduit supplying compressed air for placing the rotor into rotation, and a rotor shaft in the rotor connectable with a work tool, such as a drill. A valve member in the housing associated with the compressed-air inlet conduit is adapted to vary the inlet of compressed air for each unit of time, and an adjusting device is provided for controlling the valve member. The rotor shaft includes an axially displaceable component for controlling the valve member in direct mechanical dependence upon the torque at the work tool so as to form the adjusting device into a torque-dependent adjusting device.

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.

Abstract: A friction transmission having at least one friction disc formed as a rotating presser cylinder of a piston firmly connected with the associated shaft, with load-dependent hydraulic generation of the pressing forces, where at least on one transmission shaft a sensor is arranged for the torque transmitted there. The sensor, due to a torque-dependent movement of at least two valve parts in relation to one another, generates a torque-dependent hydraulic pressure and the necessary load-dependent hydraulic pressing force is generated exclusively by this pressure.

Abstract: A control system for a motor through which a specific rotary output is obtained from a given input signal by controlling an operational supply of fluidic energy. The control system includes a direct mechanical servo which receives the input signal to control a rotary plate directional valve through which the operational supply of fluid is communicated to the motor. The direct mechanical servo includes a compound epicyclic gear train and an intermittent motion gear mechanism which compares the input position with the output position of the motor to establish a feedback signal which repositions the rotary valve plate directional valve to a null position when the rotary output equals that requested by the input signal. The control system further includes a regulator assembly which receives a variable reference signal to control the fluid pressure of the supply fluid. The variable reference signal which represents the work performed by the motor also passes through a relief valve.

Abstract: A fluid-actuated shut-off valve for a fluid-powered tool such as a wrench including a spool valve urged to open position by a spring and having respective valve-operating surfaces subject to both regulated inlet and exhaust pressures in the tool. The valve operating surfaces and spring are arranged so the valve is thrown to its closed position by a combination of a constant regulated control pressure and the drop in exhaust pressure as the tool motor slows down and stalls under load.

Abstract: A pneumatic torque tool includes a torque responsive mechanism which actuates a valve closure member by release of an elongated actuating rod. A movable valve seat is biased in a first position by pressure fluid supplied to the tool and upon release of the actuating rod the valve closure member engages the seat to shut off air flow to the tool motor. Upon closure of an operator actuated valve the seat is biased to a second position for resetting the actuating rod and closure member.

Abstract: Pressure medium regulating device in which a fluid cell is positioned between the inlet and outlet of the device. The inlet is connected to a source of pressure medium and the outlet to a motor or other apparatus fed and operated by the regulating device. Flow through the regulator is reduced or increased in accordance with demand by the fluid cell which responds to line pressure of the pressure medium.

Abstract: In a power operated torque tool, the pressure-fluid feed is controlled by a valve which opens to start the tool, and closes to stop it. This valve is mounted on the end of a push-rod which extends along the axis of the tool. The tool also has a clutch which disengages on reaching a predetermined torque, and at the same time releases a grip on the push-rod, so that the valve can move to close the feed to the tool motor, and thus to stop the tool. The grip on the push-rod is exerted by a group of balls held in a sleeve and pushed against the rod by a tube with a tapered internal wall which surrounds the sleeve. The balls are pushed against the taper by a light spring, which is considerably weaker than the spring which holds the clutch in engagement.

Abstract: This invention relates to power tools and more particularly to an air-operated power tool commonly used for automotive or other assembly operations for installing threaded fasteners. The device of this invention shuts off the power tool as it approaches the stall condition. Motor rotation is sensed by transferring a small mass of air in proportion to the speed of the motor but independent of the air expanded to operate the motor. The air transferred is utilized to create a signal which through an air-operated valve shuts the power tool off when the speed is reduced below a predetermined amount as when the torquing cycle is nearing completion.

Abstract: Fluid motor means having a sectional housing containing a fluid flow passage therebetween is provided. The passage has a cross section which varies in response to load changes, along with means in the passage for varying the flow of pressure fluid to the motor in response to said load changes. Expansion or fluid chambers are preferably used to couple input and output members in a manner responsive to torque changes.

Abstract: A torque-applying apparatus having one or more torque motors each arranged for forcibly threading a first threaded member into tightened association with a corresponding second threaded member. A control is provided for controlling the operation of each torque motor to firstly seat the first threaded member relative to the second threaded member by a rapid threading operation at a low torque. When the seated condition of all of the threaded members is sensed, the control automatically operates each torque motor to slowly apply gradually increasing higher torque to provide a preselected maximum-torque, tightened condition of the threaded members.