Abstract: The present invention relates to an opening and closing device for an umbrella which can be easily handled by a single hand; in which a button structure is positioned between a handle and a shaft to control an open-close transmission device rotated by a ratchet gear, thereby to actuate hard steel wire thereof to retract periodically, thus the opening and closing of the umbrella can be handled by a single hand.

Abstract: A solenoid actuated water control valve incorporates a molded plastic valve body which includes an inlet portion defining an inlet chamber and having a plurality of parallel spaced holes for receiving a set of screws. A drawn sheet metal tubular fitting has a tapering tubular threaded portion integrally connected to a radial flange portion. The flange portion corresponds generally to the shape of the inlet portion and has corresponding holes for receiving the screws. The screws also extend through corresponding holes within a support bracket which has an opening for receiving the tubular portion of the fitting so that torque applied to the fitting is transferred through the screws to the support bracket.

Abstract: A plurality of gas actuated valves capable of high-speed action, great prure endurance and withstanding shock, vibration and a marine environment. A sliding member, closing the valves inlet ports, may be retained by a frangible flange. Electrically-initiated gas cartridges produce a rapid pressure rise causing the sliding member to be displaced thereby shearing the flange and allowing the sliding member to uncover the inlet ports for ambient fluid entry. A plurality of O-rings minimize functional sensitivity to external pressure and seal the valve against the entry of the ambient fluid.

Abstract: There is disclosed a tubular connector for connecting the end of a tubular gas carrying conduit to the mouth of a thermoplastic bottle containing a liquid wherein the mouth prior to use has a breachable seal. The connector comprises two oppositely facing cup means each having internal threads therein, one to be screwed to the gas conduit the other to the mouth of the bottle. The two so disposed cups are connected by axially disposed tubular means extending respectively from each bottom of the cups whereby they are maintained in spaced relationship. That cup that is attached to a gas conduit is supplied with a relief valve at the bottom of the cup whereby excess gas pressure in the system is permitted to escape. At the same time a thin annular membrane is associated with the said relief valve whereby an audible sound is achieved due to the escaping gas.

Abstract: An inverted bucket-type steam trap has a completely sealed casing of uniform wall thickness and preferably made of stainless steel. The casing is comprised of an upper part and a lower part. The lower part and the upper part both have a cylindrical wall portion which is open at one end and closed at the other end by a spherical segment-shaped bottom wall. The upper part and the lower part are affixed to each other by welding. The upper part has sidewardly extending outlet and inlet fitting means welded thereto. A valve is provided in association with the outlet fitting means. An inverted bucket is movable vertically inside the casing in response to the presence of condensate therein to operate the valve between opened and closed positions. An inlet tube is provided inside the casing and it extends from the inlet fitting means into the lower end of the bucket.

Abstract: A non-rising valve stem is provided with a shoulder that, in normal opening and closing of the valve, remains free of a complementary seat formed inside the valve bonnet. Should the valve stem packing in the bonnet begin to leak while the valve is open and under pressure, the bonnet packing gland may be backed out a few turns to effect a seal between the shoulder and seat. Then a disassembly, packing change, reassembly and testing may be effected.

Abstract: A pressure regulator comprising a body having an inlet, a first channel, an outlet for passage of gas therethrough and a chamber, a valve located within the channel between inlet and outlet for regulating outlet pressure, the inlet being in effective communication with the chamber through the valve, and a slide contacting the valve, reciprocally moveable within the chamber of the body so as to open or close the valve, biased in a direction tending to open the valve, and responsive in a direction tending to close the valve to pressure of gas which has passed through the valve into the chamber, featuring in one aspect a seal located between the body and slide to prevent the escape of gas therebetween, the seal having an annular base and an annular lip resiliently connected to the base, the base and lip forming a pocket for the gas so that the pressure of the gas helps to bias the lip outward from the base to provide an improved sealing effect, and featuring in another aspect a valve having a reciprocally moveab

Abstract: A one-way valve is provided which may be releasibly attached to a wheel brake cylinder of an automobile for bleeding the brake system of any air existing in such system. The bleeder valve has a quick disconnect which may be snapped over the bleeder outlet in sealing engagement therewith.

Abstract: A valve actuator is provided for use in conjunction with a valve having a rotatable member the rotation of which actuates the valve in dependence on the direction of rotation. The valve actuator comprises a housing and a coupling member rotatably carried by the housing and coaxially attached to the valve rotatable member. An elongated threaded shaft is rotatably mounted within the housing so that the axis of the shaft is perpendicular to and spaced from the axis of the coupling member. A nut member threadably engages the threaded shaft and a link is pivotally secured at one end to the nut member and at its other end to a radially extending portion of the coupling member. The link prevents rotation of the nut member on the threaded shaft so that rotation of the shaft axially drives the nut member along the shaft. An axial displacement of the nut member along the shaft in turn rotates the valve rotatable member via the link and the coupling member.

Abstract: A gaseous fuel mixer for an internal combustion engine includes hinged air valve doors arranged for opening in accordance with manifold depression, the doors are linked to the fuel metering means and include means for ducting the gaseous fuel into the air stream. The air valve doors can be hinged flat along a surface of the air inlet to permit alternate use of a conventional gasoline carburetor.

Abstract: The disclosure relates to a controllable valve structure, for throttling liquids under high pressure in a manner to minimize cavitation damage to the valve parts. The valve structure includes a cylindrical trim cage surrounding the valve seat and plug and formed with a relatively large multiplicity of passages for the radially inward flow of liquid. The orifices are so shaped and contoured that the effective throttling orifice of each is formed as close as practicable to the inner wall of the trim cage, causing formation of vena contracta in regions spaced as far as practicable from the walls of the trim cage. This reduces damage resulting from cavitation and correspondingly increases the useful operating life of the valve.

Abstract: Various embodiments of a proportioning valve are described and shown for location at the discharge ends of a pair of conduits wherein the movable valve member cooperates with the open ends of said conduits. The valve member can be planar or with a dihedral surface and mounted for rotation alternately into obturating relation with one or the other of said conduit open ends which may be square with the conduit axis or cut obliquely. Additionally, the conduit ends may be straight or bent so as to position their mouths either horizontally, vertically or in an oblique plane. Some of the valve members are mounted centrally while others are mounted adjacent an edge, some are mounted for movement about a vertical axis, others about a horizontal axis. An example is given of a use for the valves in combination with a vacuum loader although the valves can be used effectively for controlling discharge of fluent solid material from two sources into any space either under vacuum or positive pressure feed.

Abstract: A valve assembly is provided in which a first poppet member and at least one subsequent poppet member each having a valve face engageable with a valve seat between first and second passages. A first and a subsequent pilot valve is operative for selectively establishing communication between a fluid reservoir and a space at one side of a piston portion of each poppet member and a pair of restricted flow passages are provided in each poppet member between such space and the first and second passages, such restricted flow passages being preferably formed in the poppet members with ball check valves provided therein. Such restricted flow passages operate upon closure of the pilot valve to develop a static pressure in the space corresponding to the pressure in the one of the first and second passage which has the higher pressure therein so as to move the poppet member to and hold it in its closed position in response to pressures applied from either of the first and second passages.

Abstract: A test cup for pressure testing tubing comprising an elastomeric sleeve having a belled end, and further including an axially extending tubular portion positioned concentrically within the belled end and defining therewith a fluid-receiving cavity. The tubular portion is mounted to an internal metallic tube which projects axially into the sleeve beyond the reach of the fluid-receiving cavity in concentric relation to the bore through the sleeve. At its end opposite the belled end, the sleeve has embedded therein a plurality of circumferentially spaced reinforcing ring segments of generally L-shaped cross-section.

Abstract: A multi-core duct is constituted by a plurality of resilient conduits bunched together within a protective sleeve. Each of the conduits is formed from a high-strength synthetic plastics material and the protective sleeve is made of a flame-resistant synthetic plastics material.

Abstract: A double walled fuel line for use with fuel injection engines including first and second, nominally concentric tubes having an annular space therebetween. both of the tubes are bendable on conventional tube bending equipment and the innermost tube mounts fittings for connection into a fuel injection system. An additional fitting associated with the outermost tube establishes fluid communication to the annular space between the tubes for venting leaking fuel.

Abstract: A weaving process and apparatus for producing a slide fastener from two continuous plastic filaments (synthetic-resin monofilament), each with a multiplicity of generally helicoidal coupling elements for interlocking with the coupling elements of the opposite filament, each filament being woven integral with the threads of its respective support tape to form a tape-like unit. Each coupling element has a coupling head on a loop and a pair of shanks terminating in bight portions which connect elements of the same tape-like unit. The shanks of each coupling element, which separate the bights from the loops, are held in close abutment by warp threads, with or without weft threads which pass over and under the successive paired abutting shanks of adjacent elements. Even stronger bracing can be obtained with bulbous projections on the shanks and bights, and by extending the coupling elements the entire width of the tape-like unit, replacing all or part of the weft threads.

Abstract: The present invention discloses an improvement in angularity sensors employed in center pivot irrigation systems. A center pivot irrigation system has a plurality of self-propelled articulating span units mounting interconnected sections of water carrying conduit, each span unit has motor means and motor control means for regulating the operation of the associated motor means to maintain the span units in a pre-determined relative alignment in a vertical plane revolving about a vertical line at the center pivot of the system. The control means has angularlity sensor means which is connected between span units for sensing in a substantially horizontal plane changes in angularity between the span units relative to the desired revovling vertical plane.

Abstract: Improved paper forming and tissue transfer fabrics having enhanced stability and stretch resistance as well as improved bicrimp configuration, the fabrics being characterized by the alternate use of very high modulus and very low modulus yarns in the machine direction of the fabrics, the alternate very high and very low modulus yarns being woven using either pick and pick or two picks in a shed weaving techniques, the very high modulus yarns having an initial (1%) modulus greater than 2.0 gpd and the very low modulus yarns having an initial (1%) modulus of 0.2 to 0.8 gpd.

Abstract: A retensioning device for a shuttle-less loom in which the yarn is drawn from a yarn reserve through a pair of eyelets and a thread brake for insertion, e.g. by lances into the warp, comprises a falt chamber defined between a fixed lower plate and a movable upper plate having an opening through which the head of a nozzle passes in the closed position of the upper plate. The nozzle directs a flat stream of air into the chamber to cause the yarn therein to describe a loop with the sides of the loop nearly parallel to one another, thereby preventing tangling.

Abstract: A liquid soap dispensing system includes a closed soap container having a manually actuated dispensing pump carried therebeneath and being mounted on a bracket which has support fingers engageable with a lip on the container bottom for supporting it and a flexible retaining finger engageable with a groove in the top of the container for releasably holding it immovably against the bracket. A bottom wall extends from the bracket beneath the container and cooperates therewith to enclose the dispensing pump and is provided with an aperture to accommodate dispensing of soap therethrough. Refill of the container is by a plastic refill squeeze-bottle with a neck closed by a membrane. The neck is inserted in a wall in the top of the container, and a piercing member at the bottom of the well ruptures the membrane, whereupon soap may be squeezed from the bottle and through apertures in the well bottom, which apertures are too small to permit ready flow of soap therethrough by gravity at ambient pressure.

Abstract: Apparatus for selectively charging and evacuating a separate liquid system such as an engine cooling system, refrigeration system or the like and having a liquid storage tank, a single fluid pump and valve means for selectively connecting both the pump inlet and pump outlet for either pumping liquid from the storage tank via a connector conduit to the separate system or from the separate system via the connector conduit to the storage tank.

Abstract: A container is provided for facilitating drainage of oil from an engine. A funnel is removably attached to the top of the container in a normally inverted position. The funnel can be removed, placed in an upright position and reattached to the top of the container for receiving and directing oil or other fluids into the interior of the container.

Abstract: A system for loading a predetermined quantity of a compressible fluid into tubular cartridges or the like is provided which includes filling apparatus having filler tubes with ball valve means adjacent the outlet thereof, the outlets comprising flow constricting means for receiving the ball valve means and further including automatic means for opening and closing the ball valve means after a predetermined quantity of compressible fluid has been delivered to the tubular cartridges through the filler tube.

Abstract: This disclosure relates to a cant forming machine wherein logs are cut in advance to the predetermined length of the wood slats and pieces to be formed, after which the logs are automatically moved through a series of saws and molding heads to first cut guide grooves in the lower portion of each log, after which the log is moved onto guides where it is under full control. Following this, necessary cuts are made in the log to define a plurality of cants, followed by a final cutting of the log to separate the plural cants. The machine is adapted to continuously receive cut lengths of logs with there being conveyor means for presenting logs to the machine and a cut-off saw for cutting the logs to the predetermined length. Also, the machine has a reciprocating pusher carried by an endless conveyor chain with the pusher being connected to the conveyor chain in a manner wherein the conveyor chain may slip relative thereto in the event of a jam.

Abstract: In a container of the kind having an impermeable base and a flexible cover which is sealed into a groove or slot in the base to form an airtight package, the cover has, around its periphery, an endless male member for engaging in the slot or groove, e.g. an endless inflatable tube, which is resiliently gripped in the slot or groove.

Abstract: A pneumatic tire, after manufacture, is provided with a propellant material and a foam forming sealant material in its interior pressurizable space. The propellant and sealant are isolated from each other during normal running conditions of the tire and have no significant effect on the normal running characteristics of the tire. When a tire fails due to a puncture or the like, a loss of tire pressure and/or collapse of the tire structure and/or heat build up in the bead area due to friction permit the propellant and the foam forming materials to interreact.In one embodiment of the invention the propellant and sealant are enclosed in separate chambers of a plurality of dual-chamber containers secured to the bead portion of the tire and/or a rim base. In other embodiments a plurality of mono-chamber containers house one of the materials, the other material being uncontained in the pressurizable space.

Abstract: Effectiveness of internal cooling of the rollers in a withdrawal path for continuously cast ingots is determined by measuring the drop in surface temperature of the ingot when in engagement with the rollers. For this, a thermo element is affixed to the ingot's surface and its output is recorded or otherwise processed.

Abstract: A foundry apparatus and a method of operating a foundry in which molding material is prepared by mixing sand and water in a muller, formed into molds for sand casting of metals, and later recycled. In accordance with the present invention, fine particles of molding material are removed as a wet waste, which is subsequently delivered to the muller for mixing with sand and water in preparing molding material.

Abstract: A dummy or starter bar for starting a strand in a continuous casting installation having an open-ended mold is provided with a head which is receivable in the mold. The dummy bar head has a peripheral surface which faces the inner surface of the mold. The dummy bar head further has an end face at least part of which is inclined with respect to the peripheral surface. The end face is directed towards the inlet end of the mold. The dummy bar head is provided with a dovetail-like recess which opens to the inclined part of the end face. The recess enables the strand to become coupled to the dummy bar head and is arranged so that coupling occurs in a manner which permits the strand and the dummy bar head to become detached by relative movement thereof in a direction transverse to the longitudinal axis of the strand.

Abstract: Disclosed is a process and apparatus for multi-strand continuous casting wherein a plurality of strands may be spaced apart from each other by a distance only dependent upon the dimensions of a copper plate and water-cooling jacket of a mold because a multi-strand mold oscillation mechanism may be installed independently of the spacing between the adjacent strands and the amplitude of oscillation of each mold may be suitably adjusted depending upon the casting conditions but independently of each other. Cast products emerging from the molds are withdrawn through a multi-strand roll apron or bending unit, a multi-strand casting bow, a multi-strand straightener and a multi-strand table by a multi-strand-pinch-roll stand consisting of a plurality of coaxial multi-pinch-roller assemblies, the individual pinch rollers in each assembly being driven independently of each other.

Abstract: An installation for the manufacture of wire by projecting a jet of liquid metal or metal alloy into a cooling fluid and having a crucible for containing the liquid metal or metal alloy and provided with at least one nozzle, means for exerting a pressure on the liquid metal or metal alloy sufficient to project it in the form of a jet through the nozzle into the cooling fluid, and a cooling enclosure for containing the cooling fluid and arranged at the outlet of the nozzle, is characterized by the fact that the cooling enclosure comprises, in the portion thereof adjacent to the nozzle, means for imparting to the cooling fluid a flow which is substantially transverse to the jet, at least over a length approximately equal to the length of the jet.

Abstract: The present invention, which relates to a method and equipment for transferring heat between fluids, involves the combination of a multi-stage compressor with a series of heat-exchangers. The vapor of a condensable fluid is transmitted from one exchanger to the next by passing the same through a compressor stage, the condensate returning by direct passage with flash effect. A fluid to be cooled gives up its heat within the exchangers to the condensable fluid which is progressively vaporized.The equipment may be completed by a symmetrical part in which the condensable fluid gives up its heat of condensation to a third fluid.The invention is applicable to the use of low-level temperature heats, e.g., of geothermal origin.

Abstract: A specially modified and adapted fluidized bed is used for heat transfer between gas streams, which have a substantial temperature differential. The fluidized bed is provided with first and second inlet ports for the gases and first and second upper zones, in respective substantial vertical alignment with one another, with outlet ports in the upper zones. The hot gas is led in through the first inlet port and out through the first outlet port, whilst the cooler gas is led in through the second inlet port and out through the second outlet port. Particles of the fluidized bed are permitted to flow between the hot zone and the cooler zone of the fluidized bed, but no significant mixing of the two gas streams takes place in the fluidized bed. Efficient heat transfer is effected through the bed.

Abstract: A rotary regenerative air preheater including a housing surrounding a rotor of heat absorbent material that is adapted to rotate between a duct for heating fluid and a spaced duct that carries a fluid to be heated. Sealing means intermediate the rotor and the rotor housing include a torsion spring activated by the moving rotor that is adapted to bias the sealing means axially to provide a barrier that precludes fluid flow between the rotor and the rotor housing.

Abstract: A highly effective and efficient dry cooling system for dissipating waste heat of a steam-electric generating power plant. The dry cooling system includes an assembly of cells or modules having passively acting heat pipes installed in a Y configuration in each module. These heat pipes thermally couple the exhaust steam from a turbine flowing in a graded duct with the atmosphere. A large fan mounted at the top of each module is driven to induce air flow past exterior heat pipe portions of the module to dissipate heat picked up from the steam in the duct. The steam condensate flows down the graded duct and collects in a hot well for return as boiler feedwater. Steam from the boiler drives the turbine and is exhausted into the graded duct to repeat the cycle.

Abstract: A self-insulating water wall designed to modify the temperature of a region. Each water wall module is a single container that uses solar energy or the night environment to create convection currents which either heat or cool a storage fluid. The invention is switched between its heating and cooling modes by movement of a lever. A baffle in the container aids in maintaining the efficiency of the energy storage. A door selectively covers the wall of the container in contact with the outside environment. The inner-surface of the door is a reflector to increase the efficiency of the energy-radiating process when the door is in its open position.

Abstract: An air-conditioning device having a common housing case in which there are a heat exchanger through which used air and fresh air can flow formed with plate-shaped heat-exchanger walls which are made of aluminum foil, as well as a fresh-air blower and a spent-air blower. The interior of the housing case is divided into a fresh-air passage leading through the heat exchanger and a spent-air passage leading through the heat exchanger by the stack of foils of the heat exchanger together with internal partitions in the interior of the housing; the housing partitions comprise a controllable by-pass damper through which the spent-air entry side of the heat exchanger can be connected directly to its spent-air outlet side, and comprise a controllable recirculated-air damper through which the spent-air entry side of the heat exchanger can be connected directly to its fresh-air outlet side, the fresh-air inlet and the exhaust-air outlet of the housing case being constructed so as to be able to be shut off.

Abstract: A modular heat exchange element, adapted to be positioned in fixed relation to one or more other of such modules, may be produced as a monolithic, honeycombed body having a plurality of flow paths therethrough for at least two fluids. The body is provided with a plurality of cells extending from one face end of the body to the other face end thereof and arranged in columns of cells separated by fluid barrier wall surfaces. At least selected columns of cells are closed on both face ends of the body, with inlets and outlets for the selected cells provided by removing portions of the boundary surfaces and fluid barrier walls of the columns of cells near face ends of the body. A first fluid may enter selected columns of cells through the inlets and exit from the outlets near the other end thereof. A second fluid passes through the other selected columns of cells.

Abstract: An apparatus is provided for determining the locus of a processing zone which advances through a fragmented permeable mass of particles in an in situ oil shale retort in a subterranean formation containing oil shale. The apparatus, which functions by releasing means for providing an indicator at a preselected temperature, comprises container means, means for providing an indicator in the container, and means for releasing the indicator providing means at a selected temperature greater than ambient.

Abstract: A well testing tool system for isolating upper and lower portions of a well bore and communicating a well condition such as pressure, temperature, fluid velocity, and the like to a measuring device. The system includes a wireline supported tool train and a locking sub connectible on a removable lock mandrel adapted to be landed and locked in a landing nipple of a well tubing for releasably locking the tool train in operating position in a well bore. The tool train includes a locking probe releasably connectible at a lower end in the locking sub, an adjustable probe mandrel connected with the probe, an equalizing valve and shock absorber, and a gauge for measuring an operating condition in the well connected with the equalizing valve. The locking sub permits insertion of the probe at a relatively low force and requires a substantially larger force for withdrawal of the probe.

Abstract: A well tool is provided which is adaptable to be moved longitudinally within a well conduit. The tool contains normally retracted slip elements which are manipulated into engagement with the conduit by expander elements. An elastomeric packing element, of known construction, is expandable exteriorly around the well tool and is adapted to selectively seal with the well conduit. Booster means are provided for transmitting the compressive force defined by differential pressure acting across the packing element when the slips are in expanded position against the conduit and the packing element is sealed with the well conduit, such that the packing element is maintained in sealing relationship with the well conduit.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale. The formation comprises at least one stratum of relatively higher average kerogen content which is included in formation of relatively lower average kerogen content. A void is excavated in a retort site in the formation, leaving a remaining portion of unfragmented formation within the retort site adjacent the void. The portion of unfragmented formation within the retort site is explosively expanded toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ retort in which fragmented formation particles from the stratum of higher kerogen content have a lower surface area per unit volume than the average surface area per unit volume of the fragmented mass.

Abstract: In a method for producing hydrocarbon gas from aquifers which contain gas in water solution, water is produced from wells distributed through the aquifer and solution gases are recovered from the produced water. The aquifer pressure declines as production continues; gas comes out of water solution and a gas phase saturation builds up in the aquifer. When gas saturation exceeds a critical value, gas in gaseous phase flows through the aquifer rock to the producing wells and the ratio of total gas to total water produced increases substantially.

Abstract: Disclosed is a method for generating steam from water containing high concentrations of particulate matter such as silt, clay, etc., without the need for filtering and otherwise treating the water prior to generation of steam therefrom, especially useful for use in a viscous oil recovery process. The method comprises introducing solid particulate materials such as coarse sand, etc., into a thermal cracking unit such as, for example, that is used in the Lurgi-Ruhrgas process. The solids are heated to a temperature of at least 1400.degree. F., and on contacting the crude, cause cracking of the viscous crude into lighter molecular weight hydrocarbons and form a solid coke-like residue on the sand grain. The sand grains containing the coke residue are transported into a second chamber into which air is injected and the solid coke residue ignited. The carbon coke residue burns, raising the temperature of the sand or other granular solids.

Abstract: In a method for recovering more gas from natural water drive gas reservoirs than is recovered using present methods, large volumes of water are produced from the reservoir, and/or from the aquifer adjacent to the reservoir to reduce reservoir pressure. Residual gas after water displacement is thereby left in the reservoir at a lower pressure than it would have been had such water not been produced. Since the quantity of gas, in cubic feet corrected to standard pressure and temperature conditions, left in the reservoir at depletion is a direct function of pressure, use of the this method results in increased gas recovery.

Abstract: Fire-fighting foam effecting against burning hydrophilic or polar liquids like lower alcohols, ketones, etc. is made from concentrate containing thixotropic thickener dissolved in large amount, yet has a tolerable viscosity particularly when stirred. Heteropolysaccharide-7 or chain-shortened modifications of it are suitable for this purpose. The concentrate can also be made suitable for fighting fires on hydrophobic liquids by adding surfactants that cause aqueous film formation over such liquids.

Abstract: A cultivating machine has subsoil tines and corresponding plate-shaped elements are pivoted to the lower portions of the tines. A driving mechanism, including at least one eccentric is connected to one or more of the elements or tines and the elements are caused to pivot up and down at their working depths to only partially raise the subsoil. The driving mechanism can also be connected to a further soil working member with soil engaging bars positioned to oscillate and work the topsoil.

Abstract: An improved cultivator glove has been designed which comprises a full handed glove covering all four fingers and thumb and a point element attached to each finger and thumb of this glove wherein the point extends from one-half inch to one and one-half inches beyond the end of the fingers and thumb. The point element can be made of fiber glass or metal and can be attached to the glove by molding to the ends of the fingers and glove or by attaching said point to the underside of the fingers and glove.

Abstract: A hydraulically-operated percussive device comprises a piston/striker reciprocable in a housing and valve means adapted to intermittently pressurize a working area of the piston/striker to produce forward working strokes thereof. The housing contains a chamber adapted to be pressurized by the hydraulic working fluid to apply a continuous return force to a differential return area of the piston/striker which has a step arranged to enter a dashpot cavity at one end of the chamber to damp forward movement and thereby limit overstroking of the piston/striker. The piston/striker has an intermediate flanged portion which is a close sliding fit in the chamber end regions of which are interconnected through a conduit so that both annular end faces of the flanged portion are subject to the fluid pressure. The end faces are of different efective areas with the difference providing said differential return area and the larger end face providing the step.