Abstract: A vibratory drive includes a pulse generator and at least one actuator. The actuator includes a first fluid chamber and a second fluid chamber, the volumes of which are adjustable in phase opposition. The first fluid chamber has a fluid connection to a third fluid chamber in the pulse generator. The second fluid chamber has a fluid connection to a fourth fluid chamber in the pulse generator. The third and fourth fluid chambers each have portions that are defined by linearly moveable defining elements. The pulse generator includes a rotor that rotates relative to a first axis of rotation and that defines respective portions of the third fluid chamber and the fourth fluid chamber. The defining elements are linearly moveable in the rotor. The pulse generator includes a coupling element that is separate from the rotor. The defining elements are coupled in their movement to that of the coupling element.

Abstract: A method for automatically cycling a torque wrench. The method includes providing a hydraulic torque wrench. Providing an actuating device on the hydraulic torque wrench. Providing a switching device on the hydraulic torque wrench. Adapting the switching device to be activated by the actuating device when a piston of the torque wrench is at the end of a stroke. The embodiments of the method allow a user to ensure that a proper torque on a threaded fastener is achieved. This ensures that the pressure achieved within the system is a result of a proper torque applied to a threaded fastener being achieved, and not a result of the piston at the end of its stroke.

Abstract: The control of the pressure supply to a piston-cylinder unit (10) is effected by monitoring the pressure in the corresponding line (16) through a pressure sensor (22). This pressure is measured in fixed time intervals and the changes in pressure are determined. When the change in pressure has become zero, it is detected that the set terminal pressure has been reached so that the working operation is ended. A switching to the return stroke is effected when the pressure increase in at least one time interval is greater than in at least one of the previous intervals of the working operation. The control is independent from the type of piston-cylinder unit employed and requires no sensors at the piston-cylinder unit.

Abstract: An improved runaway control for an air motor operable on increase in speed of the air motor above a speed limit stop the motor. The control includes a pressure-responsive device having an air chamber for air under pressure. Further provided is a movable member which moves away from a first position in response to increase in air pressure in the chamber above a predetermined limit to a second position, and movable back to the first position on reduction of pressure in the chamber below the limit. The movable member, when in its first position, enables the operation of the air motor, and when in its second position, cuts off the operation of the motor. An air pump is interconnected with the air motor for operation simultaneously with the motor for delivering air under pressure at a rate related to the speed of the motor to the chamber.

Abstract: An emergency shutdown system for an air-balanced pumping unit which includes a pump motor, a walking beam driven by the pump motor, a rod string reciprocated by the beam, and an air-balance cylinder and an air receiver which together define an air spring for storing energy from the beam is disclosed. A lever arm is pivotally mounted on the walking beam and attached at one end to the rod string so that a rotational moment is exerted in proportion to the weight of the rod string. Such rotational moment is opposed by an air bag, the output force of the air bag being adjustable within the expected range of the rotational moment. Thus, by properly adjusting the air bag, loss of load on the rod string results in movement of the lever arm. A shutdown valve is operatively connected to the lever arm and bleeds air from the air cylinder upon loss of load.

Abstract: A self-reversing hydraulic control system for use with a device to be driven in opposite directional modes, especially a self-reversing pump driven by such a device. The system depends upon a flow sensing element disposed to sense flow associated with movement of the driven device and adapted to generate a stop signal responsive to the termination of such flow. A means responsive to the stop signal is then effective to shift the system from one directional mode to the other. Also featured is a sensor disposed to receive and transmit hydraulic fluid under pressure to drive the device, stoppage of the flow adapted to cause the sensor to shift position and to transmit pressurized hydraulic fluid pressure, as the stop signal via a hydraulic line. In preferred embodiments the self-reversing hydraulic control system has a two-position 4-way valve which is shifted in position by the hydraulic stop signal.

Abstract: An oil well pump jack with dual hydraulically operated piston and cylinder assemblies for pivoting the walking beam of the pump jack and including a unique control arrangement for controlling operation of the piston and cylinder assemblies. The pump jack includes a unique base or skid and an adjustable knee brace assembly to facilitate positioning of the pump jack in properly supported relation to the oil well at the oil well site. The control arrangement for the piston and cylinder assemblies includes a reversing valve, a linkage mechanism for operating the reversing valve to cause controlled oscillation of the walking beam and a cushioning device for controlling acceleration and deceleration of the oscillating walking beam to reduce abrupt tension forces exerted on the polish rod and sucker rods and impact forces imparted to the pump jack during oscillation of the walking beam.