Abstract:
A hybrid of the pneumatic and hydraulic actuators for combining pneumatically powered actuation with incompressible and controllable hydraulic damping in order to achieve smooth displacement, rapid stopping and steady and accurate positioning of the hybrid actuator in which hydraulic damping of a pneumatic actuator is obtained through utilizing positive-displacement hydraulic actuator means with zero volumetric differential.
Abstract:
Of first and second two pressure chambers which are respectively formed on both sides of a first rack and a second rack, incompressible liquid is filled in the second pressure chambers which are positioned on the sides of back pressure at a driving time of the racks, and the second pressure chambers of the both racks are caused to communicate with each other via a throttle.
Abstract:
The invention is a bi-fluid actuator for precise bi-directional movement and positioning of a mechanical object or load. The bi-fluid actuator includes a pneumatic fluid container defining opposed first and second pneumatic fluid chambers, and having a first mechanical object secured between the chambers; a hydraulic fluid container defining opposed first and second hydraulic fluid chambers, and having a second mechanical object secured between the first and second hydraulic chambers; a pneumatic fluid controller; and, a hydraulic fluid controller. Directing pneumatic fluid into either the first or second pneumatic chambers, while controlling flow of hydraulic fluid between the first and second hydraulic chambers, controls movement and positioning of the mechanical objects which may be secured to a load.
Abstract:
A piston and cylinder arrangement for opening and closing entrance or exit doors or both in a milking compartment of a fully automated milking system. The piston and cylinder arrangement comprises an elongated cylinder having two pistons connected in tandem to an elongated piston rod. The cylinder is hermetically divided into two cylindrical portions each containing one of the pistons. The piston acts against a liquid in one portion and in the other portion the piston is actuated by pneumatic pressure. The piston rod is extended through the end of the cylinder and is connected to open and close an entrance door. The cylindrical portion containing the liquid has the liquid on both sides of the piston connected by a check-valve and a by-pass valve. To block movement of the pistons, the by-pass valve is retained in a closed position by pneumatic pressure from a supply of pressurized gas for actuating the piston in the pneumatic side of the cylinder. The by-pass valve is a sliding valve urged into an open position by a compression spring when the valve is not closed by pneumatic pressure. Both the by-pass valve and the check valve are disposed external to the cylindrical housing.
Abstract:
A fluid-operated actuating device of the type including an actuating cylinder member, an axially movable actuating piston rod member, and actuating fluid connection means for introducing actuating fluid to and removing actuating fluid from the actuating cylinder member so as to adjust the relative axial position of the actuating cylinder and piston members and including structure for damping the movement of the piston rod member with respect to the cylinder member.
Abstract:
A constant speed actuator significantly characterized by being able to produce a displacement at constant speed, even though the loading on a hydraulically damped piston is substantially varied. The actuator consists of a pneumatic driving pressure which acts against a volume of hydraulic fluid, through a interface with a free piston. The hydraulic fluid, thus acted upon by the pneumatic pressure, flows to the opposite side of the hydraulic load piston through a hydraulic fluid by-pass at a constant volumetric rate regardless of the loading on the hydraulic piston. The constant volume by-pass flow is automatically controlled by employing a constant volume valve in the by-pass. Consequently, a consistent, predictable speed of actuation is achieved over a wide range of hydraulic piston loadings and pneumatic supply pressure.
Abstract:
The invention relates to actuator mechanisms and particularly provides a shock-absorbing actuator apparatus comprised of an actuator piston buffered by both a mechanical buffer and a hydraulic buffer, the mechanical buffer being comprised of stacked Belleville washers, a driven element carried on a buffer piston rod, and a driving element carried on a buffer rod, the structure acting to cushion the movement of an actuator piston.
Abstract:
An apparatus for effecting oscillatory movement of an output member comprises a pair of single-acting fluid reciprocatory motors each having a working piston reciprocal through a working stroke and a return stroke and the motors are alternately supplied with motive fluid to effect synchronous reciprocation of the working pistons in opposite stroke directions. Each working piston is connected to a common roller chain and the roller chain engages with chain sprockets around the periphery of the output member so that alternate movement of each working piston through its working stroke drives the roller chain in opposite directions to thereby impart oscillatory movement to the output member. A dampening device is connected to each reciprocatory motor to dampen the impact of each working piston at the end of both its working and return strokes.
Abstract:
Short power strokes of the ram of a catapult are obtained by high-pressure air, and the snubbing action for stopping and returning the ram is by high-pressure oil. An exhaust port in the cylinder and a floating sleeve valve marks the end of the power stroke and the beginning of the ram deceleration. Snubbing is against a cushion of oil placed end-to-end with a cushion of air. The system is closed so that no tell-tale air bubbles escape.
Abstract:
A main frame mounts an air cylinder acting through an hydraulic cylinder with the pistons of the two cylinders forwardly connected linearly moving a fluid motor, gear train and spindle forwardly in a feed stroke and rearwardly in a retraction stroke. The hydraulic cylinder controls the speed of the air cylinder during a fast portion of the feed stroke by the flow of hydraulic fluid through a major hydraulic fluid passageway from the forward to the rearward end of hydraulic cylinder, and during a slow portion of the feed stroke, a valve in the major hydraulic fluid passageway shunts the hydraulic fluid through an adjustable needle-valve-controlled, restricted hydraulic fluid passageway. A constant supply of hydraulic fluid is always maintained in the major and restricted hydraulic fluid passageways by a resiliently urged plunger in a supply chamber connected to the major hydraulic fluid passageway. Return of hydraulic fluid to the forward end of the hydraulic cylinder during a fast retraction stroke is permitted directly forwardly through the hydraulic cylinder piston by a series of check valves. Fluid for rotatably driving the fluid motor is directed through a stationary fluid supply tube extending coaxial of the air and hydraulic cylinder pistons and a common piston rod of said pistons rearwardly telescopes the stationary fluid supply tube and forms a movable fluid supply tube communicating with the fluid motor. A valve seat is formed between a radially relieved forward end of the stationary fluid supply tube and an internal annular shoulder of the movable fluid supply tube closing off the fluid supply to the fluid motor when the pistons are in fully retracted position and permitting fluid flow when the pistons are moved forwardly commencing the feed stroke.