Abstract: The brake piston return mechanism (10) comprises a housing (22) which includes housing part (50) that forms with the housing a chamber (59) and an axially extending groove (55). Disposed within the axially extending groove (55) and forming a movable portion (58) of the chamber (59) is an annular actuation piston (70). The actuation piston (70) includes a pair of seals (74) to prevent leakage. Within the housing part (50) is a bore (40) enclosing brake tube (80) that includes an interior radially extending flange (84) and an exterior radially extending flange (82). The exterior radially extending flange (82) is engaged by the actuation piston (70). Located within the brake tube (80) is an adjuster mechanism (90). After the brake tube (80) has been displaced by the actuation piston (70) and braking has ceased, the brake tube (80) is returned to a running clearance (A) by way of the adjuster mechanism (90 ).

Abstract: In a stroke adjusting device on pumps, in particular proportioning pumps, a hydraulic actuation occurs due to the fact that a hollow shaft, which guides in its interior a sliding shaft, is formed as a hydraulic cylinder, in which the sliding shaft, designed as a double action hydraulic piston, is slidable axially in both directions by means of a hydraulic fluid. Owing to this, the required axial adjusting movement of the sliding shaft is not brought out of the hollow shaft axially to the outside, whereby the two ends of the hollow shaft are kept free for the coupling of several engines or pumps.

Abstract: A hydraulic power unit for a hydropneumatic brake actuator having a power piston comprising a force piston formed with a bore therein and a take-up piston operative in the force piston bore for movement relative thereto during a brake application. This relative movement is controlled by a check valve device carried with the force piston to establish or interrupt fluid pressure communication between the respective pistons and establishes a positive clearance between a brake shoe and wheel tread, for example, during a subsequent brake release.

Abstract: In a steering system in which both front and rear wheels are steerable, the rear road wheels are adapted to be turned in the direction opposite to the direction of turning of the front road wheels only when a steering wheel is turned with a torque or effort larger than a predetermined value.

Abstract: A fluid powered actuator system includes two identical fluid powered actuators operable by respective supply pressures which are controlled by respective identical valve arrangements. Operating positions of flow control elements of the valve arrangements are applied through respective couplings to a differential arrangement which operates, if these positions differ by an unacceptable amount, to apply an error indication through respective coupling to prevent the supply pressures from being applied to the respective actuators.

Abstract: The casing of the jack is divided into two cylinders by a cross partition, with a first piston which moves in one of the cylinders and a second piston, forming two parts, linked by a rod which crosses the partition to its first part which moves in the first cylinder-shaped piston and its second part which moves in the second cylinder of the jack. The fluid is conveyed selectively either to the cylinder formed by the first piston or to the second cylinder which communicates with the first cylinder through holes drilled in the partition.

Abstract: The brake motor subassembly with automatic play compensation limitation by way of a stepped pilot piston (20), comprising a first cylindrical peripheral surface of larger diameter (21) sliding in an inner bore (7) of the control piston (1) and a second cylindrical peripheral surface of reduced diameter (24) interacting sealingly slideably with an annular gasket (17) in the piston (1), has an intermediate radial shoulder (26) which, during the movement of the pilot piston (20) because of the opposing effective cross-sections (s.sub.1, s.sub.2), interacts with the annular gasket (17) so as thereby to present a new effective surface (s.sub.3) preventing the continuation of the movement of the pilot piston (20) and thus avoiding the compression of the elastic member (11) which normally stresses the automatic compensation nut (14).

Abstract: A pump control module is provided which may form an integral part of a variable volume pump or which may take the form of a pump attachment and which is operative to continually vary the volumetric output in inverse proportion to the operating pressure at the pump discharge so as to utilize a high percentage of the available horsepower at maximum output over a portion of the operating range of the pump.

Abstract: A fluid-pressure-operated actuator is arranged to have three set positions and preferably a fail-safe characteristic in one of the three positions. In one embodiment an H-section piston moves in an actuator body and is set in its two extreme positions by fluid pressure introduced behind the web of the piston through one or other of spindles having heads and bores. To set the intermediate position, annular pistons can be moved along the spindles by pressure introduced at inlet pipes in the body until those pistons contact the heads of the spindles. The spindles are adjustable in the body to set the intermediate position of the piston and adjusting bolts set the extreme positions of the piston. For a fail-safe situation, a reservoir and control valve are introduced. As an alternative to annular pistons springs acting through top-hat shaped buffers can be used giving a fail-safe situation in the intermediate position of the piston.

Abstract: A vacuum operated actuator is provided with a centering mechanism that operates with a single spring to normally locate the output in a mid-position and also return same from both an extended position and a retracted position. The centering mechanism also includes a connector that may be changed to adjust the output for connection with the device to be actuated without changing the centering and return operation.

Abstract: A vacuum control device comprises a casing in which are disposed at least two substantially parallel movable cups, the first cup being connected to the element to be displaced. Springs are interposed respectively between the two cups and between the second cup and a bottom end-wall of the casing. Two pipes or nipples connected to a vacuum source and to atmospheric pressure open into the casing respectively within the space located between the two cups and within the space located between the second cup and the casing end-wall.

Abstract: A steering apparatus for a motor vehicle has a steering gear connected to a first set of vehicle wheels, and a selectable auxiliary steering gear connected to a second set of wheels. The steering gear for the first wheel set is connected to a steering wheel and includes a hydraulic servo mechanism which provides steering assistance to the steering gear when the force required to turn the steering wheel exceeds a predetermined limit. A hydraulic pressure transmitting device is attached to the gear output of the steering gear and is hydraulically connected to the auxiliary steering gear. The pressure transmitting device transmits hydraulic pressure to the auxiliary steering gear, when auxiliary steering is selected, which varies in correspondence with movements of the gear output of the steering gear and which is independent of the pressure supplied to the hydraulic servo mechanism.

Abstract: Variable stroke pump apparatus includes a photovoltaic array for providing electrical current to motors, one of which provides for the pumping action of a walking beam, one of which provides for movement of a control unit which varies the length of stroke of the pumping apparatus from a minimum of zero to a maximum, and one of which operates a counterweight for moving the counterweight in response to the pumping load. The apparatus includes mechanical elements which adjust the length of the stroke of the pumping arm, and a control system which controls the length of the pumping stroke in response to the output of the photovoltaic array.

Abstract: A vehicle steering system in which both front and rear road wheels are turnable in opposite directions upon low speed running and in the same direction upon high speed running, and the angle of turning of the rear road wheels for a given steering effort on a steering wheel is varied so that a large angle of turning of the rear road wheels is obtained during low speed running and a small angle of turning of the rear road wheels is obtained during high speed running.

Abstract: A tire carcass transfer device (111) having a hollow housing (112) for receiving a tire carcass (160), a plurality of flexible cups (21) arranged in a circular band around the housing, vacuum means connected to the cups (21) and fluid powered actuators (10) for radial movement of the cups. The actuators (10) each have a return spring (24) therein to move piston (14) of the actuator (10) radially outwards by a predetermined amount on cessation of operation of the fluid powered actuator. Since all the pistons (14) are moved the same distance outwards by their respective springs (24), distortions to the carcass from its circular shape are minimized. An actuator (10) having a return spring (24) operating on a rod (15) operably connected to a piston (14) to return the actuator piston to a mid stroke position is also described.

Abstract: The pump stroke extender adjusts the stroke of a polish rod normally clamped to a connector cable of an oscillating horse head for operating a sub-surface oil well pump. The extender includes a cylinder having its sides, in the preferred embodiment, connected to the double cables (connector cable) from the horse head and a piston portion clamped to the polish rod. A source of hydraulic fluid connects to the cylinder and appropriate valving arrangements cause in-flow of fluid to the cylinder to extend the piston portion from the cylinder as the polish rod approaches one end of its stroke. Hydraulic fluid is drained from the cylinder as the polish rod approaches the opposite end of its stroke. The overall stroke length of the pump can thus be extended by the travel distance of the piston relative to the cylinder, or, alternately, can be decreased by the travel distance of the piston relative to the cylinder.

Abstract: An automatic depth control system is disclosed. The system includes a floating piston hydraulic cylinder in which the floating piston is adjusted as a stop for limiting the travel of the main piston in the cylinder. A depth sensing system is provided to sense the actual depth of a implement tool on which the cylinder is mounted to provide a depth signal indicative of the depth penetration of the tool. A circuit system is provided to receive the depth signal and to control a hydraulic valve system to move the stop piston within the cylinder to adjust the working position of the implement tool. The control system includes an instrument panel having a first display indicating the actual depth of the implement tool and a second display indicating the depth limit settings predetermined by the operator. Further means are provided to monitor the actual depth and compare it to the selected depth setting and thereby correct the position of the floating piston.

Abstract: A reversing and adjustment mechanism, especially for a reversible plough adapted for hydraulically adjustable furrow width and hydraulic reversing of the plough, wherein the reversing and adjustment mechanism comprises a hydraulic cylinder (8) with a "hydraulic memory" for adjustment of the furrow width. The oil chambers on both sides of the ordinary piston (15) in the adjustment cylinder (8) communicate with a reservoir (24) via two pilot-controlled check valves (26, 25) with open passage toward the adjustment cylinder (8) and a second direction-control valve (10). The chamber (31) in the adjustment cylinder (8) between the rear head and a freely movable piston (17) communicates on the one hand with a hydraulic cylinder (7) for reversing the plough, preferably with the rod end thereof, via a first check valve (14) with open passage toward the reversing cylinder (7), and on the other hand communicates with the reservoir (24) via a flow-control valve (28) and a first direction-control valve (9).

Abstract: An apparatus for incremental cylinder length control in a hydraulic vibrator of the type having a reaction mass with a cylinder bore disposed therein, first and second end sleeves disposed in sealed movable position in the ends of the cylinder, a piston rod sealed and slidably disposed through the first and second sleeves with a piston attached to the piston rods where the improvement comprises threading the ends of the cylinder bore and forming mating threads on the first and second sleeves with means for rotating the sleeves with respect to the cylinder so that the sleeves move toward or away from the piston thereby reducing the volume of hydraulic oil between the end of the piston and the end sleeves.

Abstract: An actuator assembly has two actuators mounted back-to-back such that their actuator rods are displaced in opposite directions. Each actuator has a spring embracing the rod between two slidable collars. The spring urges the collars apart towards stops on the rod and stops on the actuator housing, so that, on failure of the actuator, the rod is displaced to a central position. The rod is driven by a motor which also rotates two discs of different diameters. Each disc has a notch in its edge which align only at the central position of the rod and allow a roller to drop into the notch. When the actuator fails, a solenoid releases a locking arm which engages the rollers, keeping them in the notches thereby preventing rotation of the discs and displacement of the rod.

Abstract: In a free piston type oscillating compressor, closed spaces separate from gas springs are provided, and pressures of the closed spaces are regulated, whereby the amplitude, and central position of the stroke, of a free piston can be precisely controlled.

Abstract: A vacuum control device comprises a casing in which are disposed at least two substantially parallel movable cups, the first cup being connected to the element to be displaced. Springs are interposed respectively between the two cups and between the second cup and a bottom end-wall of the casing. Two pipes or nipples connected to a vacuum source and to atmospheric pressure open into the casing respectively within the space located between the two cups and within the space located between the second cup and the casing end-wall.

Abstract: An air actuator device is provided for manually operable hydraulic valves having a valve spool moving in a bore in a valve housing in the form of an actuator housing adapted for attachment on the valve housing and having a bore carrying a piston coaxially engageable with the spool end, spaced openings in the actuator housing communicating with the bore therein to introduce air to act on opposite sides of the piston and resilient means on at least one side of the piston normally urging the piston and spool to a closed position.

Abstract: A gas spring, having a collapse safety feature operable in the event of psure loss, is provided, for use, for example, as a counterbalance for flaps or vertically adjustable structures. A movable partition is arranged between the piston and the head of the cylinder of the gas spring, and is exposed on one side to a closed gas chamber under pressure, while on the other side the gas volume effecting the extension force of the piston rod is present between the piston and the partition. In event of pressure loss in the gas volume on either side of the piston, the movable partition will meet the piston and act as a safety to prevent abrupt release or lowering of the object for which the gas spring is to serve as a counterbalance.

Abstract: A tamping head for a mobile track working machine comprises a tamping tool carrier vertically adjustably mounted on the machine, a vibratory tamping tool mounted on the carrier for immersion in a crib for pivoting towards and away from an adjacent tie in a reciprocating stroke between two end positions, a hydraulic drive for pivoting the tamping tool, the hydraulic pivoting drive including a cylinder element and a piston element, a reciprocating stroke limiting stop cooperating with the hydraulic pivoting drive for selectively adjusting a respective one of the end positions, and a hydraulic actuator for setting the stop for the selective adjustment of a respective end position, the hydraulic actuator including a cylinder element and piston element, one of the elements being movable in relation to the other element and the axes of the hydraulic pivoting drive and of the hydraulic actuator being parallel to each other, the hydraulic actuator being mounted on the hydraulic drive and the stop being constituted by

Abstract: A drum brake hydraulic wheel cylinder assembly comprises a pair of piston assemblies and an abutment member. The piston assemblies are of the kind comprising an adjustable variable length tappet assembly having interengaged screw-threaded components. To enable thrust to be transmitted from one adjacent brake shoe to the other, i.e. for parking purposes, the abutment member is slidable in the cylinder bore against a spring centering device.

Abstract: Method of and device for producing electric energy from a cyclic combustion process. The device includes two oppositely disposed aligned spark ignited internal combustion engine cylinders axially spaced from each other, means rigidly connecting the pistons so that they reciprocate in unison in their respective cylinders, and a reciprocable electrical linear generator-motor unit driven by said reciprocatory piston system. The generator-motor unit includes a very light coreless (ironless) coil rigidly attached to and reciprocatory with the piston system, the said coil reciprocating through a constant strength magnetic field. The beginning of the combustion process (or cycle) in each combustion chamber takes place at the lowest possible compression ratio sufficient for the initial ignition of the fuel-air mixture, the combustion process proceeding at a diminishing volume under the pressure from the compression- and combustion-forces of the opposite combustion chamber-piston system.

Abstract: An infinitely variable, double-acting positioning linear actuator which responds proportionally to fluid pressure includes a hollow cylindrical housing and an actuating rod axially movable through the housing. Two partitions cooperate with the actuating rod for movement therewith and define within the housing a spring chamber and first and second actuating chambers which are at opposite ends of the spring chamber. A compression spring is mounted within the spring chamber and each actuating chamber has a fluid port to communicate with pressurized fluid. First and second retaining structures within the spring chamber cooperate with respective ends of the spring and each have a respective stop. The spring chamber has a limiting structure which cooperates with the stops to hold the stops spaced apart at a particular spacing when the actuator is centered.

Abstract: A high resolution servo actuator is responsive to an electronic control or manual control. An output shaft having fast response and infinite positioning for stroking a manual servo valve on a pump is rotated by hydraulic power. A set of hydraulic working cylinders and centering cylinders are connected through a rack and pinion drive to a shaft. Centering cylinders utilize stop tubes to prevent its pistons from traveling past the center position and applying a constant force to center the shaft. A directional valve controls the flow of hydraulic fluid to the working cylinders for driving the shaft throughout its range of travel. An electrohydraulic servo valve converts the electronic control signal into hydraulic flow to the actuator. Shaft position feedback is developed and connected to the electronic control.

Abstract: Method and apparatus for sustaining the oscillatory movement of an oscillating device of the type comprising a mass oscillating between dead points on opposite sides of a point of equilibrium, with a potential force acting to return the mass toward the point of equilibrium. This potential force is greatest at the dead points and the speed of the oscillating point is greatest adjacent the point of equilibrium. A force is applied to the device from a motive source, which force is greater than the maximum potential force at a speed lower than the speed of the device adjacent the point of equilibrium. The force of the motive source is applied to the oscillating device on the portion of the path of movement of the oscillating device preceding one of the dead points, and the application speed of the force of the motive source is higher than what would be the instantaneous speed of the oscillating device along that portion of its trajectory were the force of the motive source not applied.

Abstract: Method and apparatus by which a malfunctioning downhole pump of the reciprocatory type can be rendered operative by bumping the pump piston against structure associated with the pump barrel. The invention is carried out on a reciprocatory downhole pump of the type which is actuated by a rod string. The rod string is reciprocated by a pumpjack unit. A hydraulic jack apparatus is interposed between the hanger bar and polish rod clamp of the pumpjack bridle assembly so that the hydraulic jack can be extended to enable spacers to be removed or inserted at a location which changes the relative position of the polish rod clamp and hanger bar, and which also changes the relative position of the downhole pump piston and pump barrel.

Abstract: A yoke type engine wherein the orbital path of the slider is alterable to effect piston stroke and compression ratio changes. A crank component has a crankpin which carries and positions the slider. A boss of the crank component is carried by a control shaft in an offset manner. Timing gears normally drive the control shaft in synchronization with the crankshaft to maintain a constant stroke and compression ratio. Relocation of certain timing gears by an actuator causes the control shaft to rotationally advance or retard to reposition the crank component carried thereby to in turn alter the orbital path of the coaxial crankpin and slider relative to a crankshaft axis. Accordingly, high and low compression orbits for the slider may be effected to best suit engine loads. A variable length throw couples the slider to the crankshaft. The orbital path of the slider provides increased crankshaft leverage over conventional engine arrangements.

Abstract: A fluid actuated control device for operable connection with a hydraulic valve, such as a pilot valve, and comprising a coupler bolt secured directly to the valve spool, a fluid actuated cylinder and piston assembly connected with the coupler bolt for reciprocation thereof, a helical spring member disposed around at least a portion of the coupler bolt and cooperating with a pair of oppositely disposed spring retainer cups for maintaining a normal neutral position for the valve spool, the coupler bolt being reciprocal by the fluid actuated cylinder and piston assembly upon the application of fluid pressure to the assembly for shifting of the valve spool from a remote position without interference with the normal manual operation of the valve.

Abstract: A two-stage, hydro-pneumatic actuator suitable for use as a railway vehicle brake. The hydraulic cylinder comprises a large diameter bore in which a low- and a high-pressure piston operate jointly during a first stage of operation to effect a high volumetric displacement of hydraulic fluid via a small diameter bore in order to take up the clearance between the brake shoes and wheel. As the brake shoes contact the wheel, the high-pressure piston enters the small bore to interrupt further displacement of hydraulic fluid from the large bore. The force of the high-pressure piston alone during this second stage of operation produces the required brake forces with a high multiplication factor. Make-up fluid is drawn into a chamber on the backside of the low-pressure piston during a brake application stroke an amount corresponding to the over-travel of the high-pressure piston and is subsequently discharged into the hydraulic cylinder during retraction of the brakes to compensate for brake shoe wear.

Abstract: An active, mechanical hydraulic control device for vehicles including watercraft and aircraft, comprises an acceleration pick-up having a relatively small mass. Movements of the mass are sensed by a nozzle and deflection plate system which controls as a preamplifier the displacement of a power drive member provided with one or more control apertures, the flow cross-sectional areas of which depend on the instantaneous position of a piston to which the power drive member is connected. The movements of the mass vary the gap width between the nozzle or nozzles and the deflection plate forming part of the movable mass. The change in the gap width controls the adjustment or displacement of the power drive member through a follower amplifier formed by the piston. The central or balanced position of the piston is assured by the control apertures forming respective piston position responsive valves.

Abstract: A dual mode vibrator (DMV), in its hydraulic cylinder, automatically provides a shorter stroke for higher frequencies and a longer stroke for lower frequencies. The cylinder contains a pair of sleeves, each sleeve having one diameter portion sufficient to slideably engage the piston and having a smaller diameter portion to slideably engage the piston rod. The sleeves themselves are moveable within the cylinder, such movement being effected by the application of high pressure on one end or the other. When the sleeves are moved together, the stroke is effectively shortened. When the sleeves are moved apart, the stroke is effectively lengthened.

Abstract: A fluid actuated shift bar housing assembly for a change gear transmission wherein the shift bars are biased to an axially centered neutral position by constant fluid pressure in a constantly pressurized chamber and are selectively axially moved to an axially displaced gear engaged position by selective pressurization of a selectively pressurized chamber. A detent mechanism is provided for retaining the shift bars in the displaced positions thereof, said detent providing a resistance to axial movement of the shift bars having a smaller axial magnitude than the axial centering bias of the constant fluid pressure.

Abstract: A piston-cylinder device, such as a Rankine cycle engine, is provided with one or more variable displacement cylinders and variable stroke pistons for accommodating loads of variable torque. Cylinder displacement is varied by a movable cylinder head internally of the cylinder and auxiliary to a fixed cylinder head, and piston stroke is varied by a variably fulcrumed lever linking piston connecting rods with a crankshaft. For the engine particularly, load torques are continually sensed and cylinder displacement adjusted accordingly. In turn, the position of the movable cylinder head is continually sensed, and the lever fulcrum adjusted accordingly.

Abstract: Apparatus for incremental cylinder length control in hydraulic seismic vibrators having increased frequency range. The vibrator apparatus (10) of the type having a reaction mass (38) and axial cylinder bore (42) utilizes hydraulically movable end sleeves (86 and 96) in each end of the cylinder bore (42) so that the end sleeves (86 and 96) can be controllably positioned thereby to alter the cylinder volume and adjust the hydraulic drive system (18) for maximum efficiency relative to operating frequency.

Abstract: A portable positive displacement respirator/ventilator is provided for both a pressure sigh and a volume sigh of predetermined duration and frequency by providing a variable length crank arm connecting a piston through a connecting rod by mounting the connecting rod on a circular toothed gear, pivoting the gear for movement at its center and driven on its outer edge with a separate motor driven pivot gear which when moved relocates the effective length of movement of the point of attachment of the connecting rod thereby changing the volume swept by the piston for the same arc of reciprocal movement of the larger circular toothed gear enabling both a volume change or a volume sigh with the device. A cooperating multiplicity of adjustable pressure regulating valves where at least one can be intermittently closed during the operation of the device regulates ventilation pressure or breathing pressure and sigh pressure.

Abstract: A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

Abstract: A fluid control system includes a fluid motor 11, a control valve 12 for directing fluid flow to and from the motor 11, and a control valve actuator 14 for operating the control valve 12. The control valve actuator 14 includes an actuator member 32, a feedback member 44, and a spring 46 which exerts a force on the actuator member 32 whose magnitude varies with the relative positions of the actuator member 32 and the feedback member 44. A command pressure signal moves the actuator member 32 to operate the control valve 12 in order to direct fluid flow to and from the fluid motor 11. A feedback link 41 connects the feedback member 44 to the fluid motor 11. The actuator piston 32 is slidably carried on the feedback member 44, so that any drifting of the fluid motor 11 results in immediate movement of the actuator member 32 and control valve 12 to correct the drifting.

Abstract: A hydraulic cylinder having a piston position memory element is disclosed, and is particularly adapted for use with propulsion units for watercraft. A valve seat (76,242) is frictionally retained in a bore of a cylinder (24,200) and cooperates with a valve (72,266) in a piston (70,244) to stop the piston (70,244) in a preset position by blocking the flow of fluid through the valve (72,266).In a first embodiment, a poppet valve 60 is provided to allow a piston (70) to move to dissipate the energy of a collision of a watercraft propulsion unit with a stationary object, the piston (70) being provided with a valve (72) to allow the piston (70) to return to its original position. The valve seat (76) having remained in its original position and being provided with an unrestricted aperture (78) stops the piston (70) in its original position.

Abstract: A differential pressure unit having overrange valves loosely mounted on a valve stem connected between the ends of a respective pair of movable bellows ends. A pair of spiral range springs bias both valves toward open positions. The valves include annular elastomers bonded to the edges of the apertured discs. The apertures in the discs act to allow the elastomers to seat and to unseat without causing lock-up. The discs are retained between plates and snap rings.

Abstract: A fluid activated pump that is particularly well suited for use in analytic machines of the type that need to accurately meter quantities of sample solutions. The pump, which includes a pump piston driven by a power piston, is powered either hydraulically or pneumatically. Also included in the pump is a displacement adjustment piston, which is either hydraulically or pneumatically controlled, and which, through a suitable shaft-type linkage, can adjust the length of the power piston's stroke, and thus permit either a large or small displacement of the pump piston. The fact that the pump piston's displacement can be changed means that the pump of the present invention can more efficiently meter solutions into various desired ratios, and can reduce the chance of cross-contamination of sample solutions by dispensing a large amount of rinsing solution after dispensing a relatively small amount of sample solution.

Abstract: A polish rod jack system for an oil well pumping units that utilizes a sucker rod; incorporating a hollow hydraulic ram to raise and lower the sucker rod string; hoses and tubing to connect the hydraulic ram to a remote manifold and in turn to a hydraulic pumping source; a hydraulic and electric switchgage to stop a prime mover in the event of pumping unit and system malfunctions and or failures; quick-disconnect fittings to facilitate connection and disconnection of the hydraulic ram from the system when the well is being serviced and to allow rapid connection and disconnection of a hydraulic pump at the remote hydraulic manifold to allow the bottom hole pump to be respaced and fine tuned while the pumping unit is in operation to maximize production.

Abstract: An improved electro-pneumatic monitor for double safety valves controlled by solenoid-operated pilot valves. The monitor comprises a relatively short spool centrally held by oppositely disposed captive springs. The sensing passages are provided with relatively small orifices which help to de-sensitize the monitor. The resulting construction is resistant to shifting in response to minor double valve irregularities which otherwise could create undesired lockout conditions.

Abstract: A vacuum motor for controlling a carburetor choke valve in which the stroke of the motor is limited to a predetermined length for a predetermined period of time after which the length of stroke is increased a predetermined amount.

Abstract: A positive displacement pump, especially a high-pressure piston pump, has a piston which is mounted for reciprocation within a pumping chamber. The piston is reciprocated by a drive including a crank, a first connecting link eccentrically mounted on the crank, a second connecting link articulated to the first connecting link and to the piston, and a control link connected to said first and second connecting links for pivoting about a common axis therewith and having a free end portion supporting a roller movable along and in contact with a curved cam surface. The roller is held in contact with the cam surface by a pivotally mounted support link.

Abstract: A vacuum operable unit for use in an ignition distributor of an internal combustion engine comprising a casing divided into first and second chambers by a diaphragm. A push rod is coupled to the diaphragm and extends through one wall of the first chamber, a seal engaging the wall of the chamber and the push rod so as to permit movement of the push rod with the diaphragm, while sealing the first chamber. First and second springs are positioned in the first and second chambers respectively, and either spring is operable on the diaphragm as the diaphragm moves in a direction to reduce the volume of the respective chamber. The housing supports a pair of abutments associated with the springs respectively, the springs engaging their respective abutments when the diaphragm is in a central position, so that in the central position neither spring acts on the diaphragm.