Showing papers on "Piston published in 1969"

Generation of acoustic pulses by baffled plane pistons

Abstract: One of the earliest investigations of the acoustic disturbance created in a fluid of semi-infinite extent by the movement of a piston surrounded by an infinite plane rigid baffle was undertaken in 1878 by Rayleigh [1], who studied the harmonic oscillations of a piston of arbitrary shape. In subsequent years, a number of authors have presented methods for studying the “baffled piston problem”. A large portion of the literature has been concerned with a circular piston and particular attention has been devoted to the case in which the small amplitude oscillations of the piston are harmonic. References to these earlier works are given by Chadwick and Tupholme [2]. A solution to the more general problem in which the normal velocity of a circular piston is an arbitrary function of time was derived from the corresponding time-harmonic solution by Oberhettinger [3] and obtained more directly by Miles [4, see also 5]. Kozina and Makarov [6] considered the acoustic fields produced by the time-dependent motion of an arbitrarily-shaped piston.

Kraftstoffeinspritzpumpe fuer Brennkraftmaschinen

Abstract: The fuel injection pump has a pump piston (11) driven by a cam drive (13, 14) and an injection timing adjusting device (33) for the drive. The adjusting device comprises a piston (37) displaceable in a cylinder against a spring bias (40) by speed-dependent pressure fuel supplied to a chamber (41) from which extends a relief line (44) controlled by a solenoid valve (45). A sensor (48) is provided for ascertaining the actual instant of injection by detecting a variable proportional to the movement of the adjusting piston (37) occurring during each injection operation. The sensor (48) is connected to a control device (46) in which the actual instant of injection is compared with the optimum instant of injection, and the solenoid valve (45) is triggered in the required manner. The movement of the adjusting piston (37) is limited by a stop (52) in the direction to retard the instant of injection. Since the sensor (48) is unable to produce a signal when the piston is against the stop, the control device (46) also acts to move away from the stop (52).

Oral hygiene appliance

Abstract: An oral hygiene appliance comprising a housing having a hollow base member which supports a liquid reservoir container and a storage and display compartment for the jet nozzles and jet nozzle handle. A liquid pump assembly of the reciprocating piston type is mounted in the base member such that a spout in the bottom of the reservoir container feeds a liquid to the pump chamber. This liquid is converted to a sequential series of liquid pulses by the pump and then delivered through a coiled tube to a jet nozzle control handle which discharges the liquid pulses from a jet nozzle. The jet nozzle control handle has a normally closed valve element to prevent the discharge of the liquid pulses until opened by pressing down on the jet nozzle''s fluted knob and has an adjustable feedback valve element that controls the portion of each liquid pulse that is fed back through a second coiled tube to the pump.

Self-similar piston problems with radiative heat transfer

Abstract: A differential approximation for the equations of radiative transfer in a grey gas is applied in a study of the effects of thermal radiation upon the classical problem of the compressive action of a plane, cylindrical or spherical piston. The ambient gas ahead of the precursor shock wave is supposed cool and the shock wave transparent, whilst the piston is taken to be neither an emittor nor reflector of radiative energy. It is shown that self-similar flow patterns may arise if the ambient density and piston speed are both non-uniform with variations linked to the absorption coefficient which is assumed to be density and temperature dependent. Detailed flow patterns are obtained in the case of general opacity and also in the transparent limit from which it is deduced that under certain conditions the approximation provided by the latter may be rather dubious.

Composite resin filling syringe and technique

Abstract: THIS DISCLOSURE IS DIRECTED TO A DENTAL MATERIAL CARRIER AND AN APPLICATOR GUN THEREFOR. THE DENTAL MATERIAL CARRIER COMPRISES A NOZZLE PRE-LOADED WITH A PREDETERMINED AMOUNT OF A DENTAL FILLING MATERIAL AND HAVING A DISPLACEABLE PISTON TO EFFECTIVELY SEAL THE DENTAL MATERIAL WITHIN THE NOZZLE UNTIL USED. OPERATIVELY ASSOCIATED WITH THE PRE-LOADED NOZZLE IS AN APPLICATOR GUN ADAPTED TO DETACHABLY RECEIVE THE PRE-LOADED NOZZLE AND HAVING A PLUNGER FOR EFFECTING DISPLACEMENT OF THE PISTON TO EXTRUDE THE FILLING MATERIAL FROM THE CARRIER AS DESIRED.

Piston for internal combustion engine

Abstract: This specification discloses a cooling system for a piston formed of two parts and joined by brazing within annular grooves Passages for cooling fluids are conveniently formed before the separate pieces are joined and are positioned such that the high temperature at common joined areas is effectively limited to prevent temperature deterioration of the bond between the two joined pieces In addition, the cooling fluid transfers heat away from a head portion of the piston and means are provided to utilize as a cooling fluid a lubricating fluid normally present at a pin-bearing surface of the piston

Power-driven reciprocating bone surgery instrument

Abstract: A bone surgery tool is provided with a reciprocating drive means. The tool and a flexible drive band can be enclosed in a shroud to protect tissue against contact with the tool or the driving means. The shroud can also contain a channel for a flushing fluid. The power unit can utilize a double-acting fluid piston, with the reversal in the direction of movement of the piston being effected by a fluidic control device.

Electromagnetic fuel injection spray valve

Abstract: The nozzle valve needle is closed by a compression spring housed in a space that is separate from the space in which the pressure determines the opening and closing of the needle. In another embodiment, a piston is acted upon by the pressure in this latter space to close the needle.

Piston and piston rings unit for an internal combustion engine

Abstract: The invention has for its object, on the one hand, all means which protect, at least partially, the internal face of the sealing joint placed between the lower adjacent faces of the piston ring and the piston groove against the high pressures which, from the combustion chamber pass between the compression ring and the bottom of the groove and also into the crosssectional or gap clearance of the compression ring, and on the other hand, a support for the said joint, which is not affected by creep, is annular, is not fixed to the piston and is arranged at least under the periphery of the said joint between the joint and the lower face of the piston groove, the peripheral face of the support being maintained at least in proximity to the cylinder and having as a maximum narrow discontinuities, the maximum clearances of this proximity and of these discontinuities being smaller than those in which the material of the said joint begins to creep, under the conditions of temperatures and pressures reached during the operation of the engine.

Constant strain jar

Abstract: A jar for removing a fish from a well, in which a piston is moved in a chamber and then released to allow the hydrostatic pressure of fluid in the well to move the piston against an anvil. Such a jar in which the piston is repeatedly shifted in response to rotation of the running in string of pipe.

Compact, implantable apparatus for pumping blood to sustain blood circulation in a living body

Abstract: An artificial heart system for implant is disclosed in which a deflatable bladder provides a straight-through blood path. The bladder is disposed in a gas filled chamber, the volume of which is controlled by a piston in the immediate vicinity of the bladder to provide pumping action. The piston is driven by a motor. A pressure equalizing bypass as between chamber and atmospheric pressure, and a check valve provide local autoregulation for the pump. A pacemaker can be operated in synchronism with the drive to simulate, for example, the natural right heart while the natural left heart is deactivated or bypassed.

Liquid pressure-operated frictional clutch apparatus

Abstract: A fluid pressure-operated friction clutch is provided with a piston operating within a pressure chamber and constituted by two piston members having respective return springs of different strengths so that the pressure chamber can be opened to the atmosphere through a small escape passageway by the advance movement of one piston member whereafter the passageway is closed by the relative movement of the other piston member, whereby the piston which is coupled to frictional clutch plates applies a weak initial force to engage the plates without shock and a subsequent strong force to fully engage the clutch plates.

Fluid force applying device

Abstract: A WORK HOLDING CLAMP IN THE NATURE OF A SELF-CONTAINED HYDRAULIC CYLINDER-PISTON UNIT IN WHICH ONE OF THE FORCE APPLYING MEMBERS, FOR EXAMPLE THE PISTON OR RAM, IS ROTATABLE AND AXIALLY MOVABLE IN ITS FORCE-APPLYING STROKE.

Disk brake with noise-limiting brakeshoe

Abstract: A brakeshoe adapted to limit noise generated by a disc brake wherein an intermediate plate, interposed between the backing plate of the brakeshoe and the piston, is affixed to the backing plate and provides force transmission between the piston and the backing plate which is offcenter from the centrum of the discengaging surface of the brake lining, the force-transmitting portion consisting at least in part of a thermal insulator.

Gas system for autoloading firearm

Abstract: A gas system for an autoloading firearm wherein the gas piston is operative to seal the gas cylinder against high-pressure combustion gases during early stages of recoil of the firearm after firing thereof. As the force of recoil decreases, the seal is broken and lower pressure gases are bled into the gas cylinder to actuate the gas system.

Apparatus for expanding holes

Abstract: A hole expander for use in conjunction with well bore drill strings which has a tool body defining a cylinder, an axially movable piston disposed in the cylinder, and a skirt portion secured to the piston. A plurality of radially arranged arms have one end secured to the tool body and another end adapted to receive cutting tools such as rotary cone cutters or abrasive cutters that are pivotal about axes transverse to an axis of the cylinder and are movable in an axial direction over a predetermined distance. Sides of the arms adjacent the skirt portion have a configuration to engage the skirt portion. When the piston moves axially in response to pressure being applied to the cylinder, the arms pivot outwardly relative to the axis of the cylinders. An intermediate skirt engaging surface of the sides of the arms is angularly inclined relative to the axis of the cylinder and engages an end of the skirt portion. When the arms are farthest removed from the cylinder in an axial direction the intermediate skirt-engaging surfaces of the arms are disposed adjacent the free ends of the skirt portion of the cylinder and bias the skirt portion, together with the piston, in a direction towards the cylinder. When the cylinder is fully extended a skirt-engaging surface of the arms engages a periphery of the skirt and locks the arms in an outwardly projecting position.

Portable mechanical ventricular assistance device

Abstract: A portable mechanical ventricular assistance device including a ventricular assistor cup designed to receive the ventricles of the heart. The cup assembly is comprised of a rigid shell having a configuration generally conforming to the surface configuration of the heart ventricles and a flexible liner which is caused to contract and expand about the heart ventricles to effect the pumping action. The heart ventricles are retained within the cup by a substantially sustained negative pressure while the pumping action is produced by the application of alternating positive and negative pressure pulses to the cup. Both the sustained negative pressure and the positive and negative pressure pulses are generated by a hand pump assembly which includes a manually operable handle connected through a piston rod to a reciprocating piston mounted within the cylinder of the pump. The piston effectively divides the cylinder into two chambers, one of which is coupled through a conduit to provide the sustained negative pressure to the cup. The remaining chamber is coupled through a second conduit to the ventricle assistor cup to provide for the alternating positive and negative pressure pulses. Suitable adjustable relief valves are provided in each of the conduits to regulate the pressure levels and the positive or negative pressure directed to the cup.

Air-pollution-free automobile and method of operating same

Abstract: An air-pollution-free internal combustion engine and method for operating such engine in which the engine has at least one cylinder, an exhaust port and exhaust valve, fuel, oxygen gas and water spray injectors and a piston in the cylinder, throttle valves for the injectors, a fuel storage and supply system for feeding hydrogen gas or liquid gasoline to the fuel injector, an oxygen storage and supply system for feeding oxygen at first and second pressures to the oxygen gas injector and a water recovery system for recovering water from the exhaust discharged from the cylinder and for feeding the recovered water to the water spray injector.

Parking lock for transmissions

Abstract: THE PARKING LOCK HAS A PISTON WITH A ROD THAT ENGAGES AND LOCKS A LOCKING WHEEL FIXED TO A TRANSMISSION OUTPUT SHAFT. FOR UNLOCKING THE OUTPUT SHAFT, A HYDRAULIC CONTROL VALVE IS OPERATIVE TO DIRECT PRESSURE FLUID TO THE PISTON TO MOVE THE ROD FROM ENGAGEMENT WITH THE LOCKING WHEEL TO AN UNLOCK POSITION. WHEN THIS POSITION IS REACHED A BLOCKER PIN AUTOMATICALLY MOVES TO KEEP THE PISTON IN THE UNLOCK POSITION UNTIL THERE IS A TRANSMISSION LOCK SIGNAL. ELECTRIC CONTROLS ARE ENERGIZED TO EFFECT THE SHIFT OF THE HYDRAULIC VALVE TO DUMP THE UNLOCK PRESSURE FLUID AND ALSO TO WITHDRAW THE BLOCKER PIN FROM ITS BLOCKING POSITION. A SPRING DEVICE THEN EFFECTS REENGAGEMENT OF THE PISTON ROD AND THE LOCKING WHEEL.

Compressed gas operated gun having variable upper and lower pressure limits of operation

Abstract: A compressed gas operated hand gun includes an annular firing chamber defined between the sides of a main piston and the wall of a bore, the forward end of the piston cooperating with an annular valve seat which communicates with a projectile-holding chamber. In a cocked position the piston is held in sealing engagement with the valve seat by a trigger assembly and is biased in an opposite direction by the gas pressure in the firing chamber. Upon actuation of the trigger assembly the piston moves away from the valve seat and releases the charge of gas against the projectile. A fresh charge of gas is introduced into the firing chamber automatically from a high pressure gas chamber by a piston valve assembly concentrically disposed in the main piston and operated in response to gas pressure in the high pressure chamber.

Sealed piston compressor or pump

Abstract: A reciprocating piston compressor or pump in which the pistons are spaced from their housing walls and supported for reciprocation by elastomeric guides or supports that will allow the pistons to reciprocate. A preferred elastomeric support or guide consists of a telescoping metal-elastic belt wound around the piston and bonded to the housing and piston walls. Either the elastomeric guides or separate resilient seals seal the space between the piston walls and the housing so that upon reciprocation fluid may be pumped or compressed from an inlet valve to an outlet valve on one side of the seal and the reciprocating mechanism may be independently lubricated on the other side of the seal.

Automatically adjustable shock absorbers

Abstract: A FLUID PRESSURE SHOCK ABSORBER OF THE TYPE HAVING A CYLINDER WITH A PISTON SLIDABLY MOUNTED THEREIN SEPARATING THE CYLINDER INTO VARIABLE VOLUME CHAMBERS, THE PISTON MOVEMENT DECREASING THE SIZE OF ONE OF THE CHAMBERS IN RESPONSE TO THE SHOCK LOAD EXERTED THEREON CREATING A PRESURE IN SUCH CHAMBER WHICH IS FUNCTION OF THE SHOCK LOAD. A PLURALITY OF SPACED APART PORTS IN THE CYLINDER CONNECT THE CHAMBERS THROUGH WHICH FLUID IS FORCED FROM ONE CHAMBER TO THE OTHER WHEREIN THE RATE OF SAID FLUID FLOW CONTROLS DECELERATION OF THE PISTON AS A SHOCK LOAD IS DISSIPATED, AND INCLUDING MEANS FOR AUTOMATICALLY VARYING THE RATE OF FLUID FLOW THROUGH THE PORTS AS A FUNCTION OF A PRESSURE FORCE IN SAID ONE CHAMBER.

Shock absorber and fluid-compensating means

Abstract: In a shock absorber having a cylinder and two axially spaced pistons on the same piston rod, a tubular membrane attached to the piston rod between the pistons is filled with compressed gas to compensate for the changes in the cylinder volume available to a liquid when the piston rod moves into and out of the cylinder cavity. In a modified arrangement, the compensating chamber is mounted on the piston rod outside the cylinder behind a flexible membrane to which the liquid in the central cylinder compartment has access through a bore in the piston rod.

Forming apparatus for hydraulic press

Abstract: In a hydraulic forming tool of the diaphragm type, the punch and the work holder or die member are rigidly mounted on separate pistons that move in communicated cylinders, so that downward movement of one effects upward movement of the other by reason of displacement of fluid from the bottom of one of said cylinders to the bottom of the other. Adequate forming force is assured by metering outflow of fluid from the upper portion of the cylinder having the upgoing piston.

Wave motion compensating apparatus for use with floating hoisting systems

Abstract: The dead end of the drilling line of the hoisting system of a floating drilling rig makes multiple passes between a stationary sheave assembly and a movable sheave assembly and then runs to a dead line anchor to which it is tied. A piston mechanism including a cylinder, piston, and piston rod is located on the floating rig structure and is coupled to the movable sheave assembly for controlling the spacing between the stationary and movable sheave assemblies. Fluid control apparatus communicates with the piston mechanism for controlling the fluid pressure therein for minimizing variations in the drilling line tension as the floating drilling rig or other type of floating structure rises and falls with the sea waves. The piston rod is subject to a pure tension load at all times, thereby enabling the rod to be of any suitable length to accommodate any wave height encountered.

Breech loaded syringe and method of breech loading same

Abstract: A syringe wherein a piston is moved axially through a tubular barrel to deliver liquid medicament and the like outwardly through a needle connected through an inner end of the barrel. A control is provided for selectively deforming the piston to permit the barrel to be preloaded with the liquid medicament through the breech end thereof with the piston being brought into engagement with the liquid while a fluid bypass passage is provided around the piston to the breech end of the barrel, thereby to vent air outwardly from the space between the piston and the liquid medicament during the insertion of the piston.

Hydraulically operable linear motor

Abstract: A hydraulically operable linear motor with a double-acting reciprocable piston in a cylinder, in which one side of the piston has connected thereto a piston rod so as to form with this one side an annular piston surface which is continuously exposed to a desired working pressure. The other side of the piston is by means of a hydraulically actuated control valve alternately exposed to the working pressure and to the pressure in an exhaust conduit. The pressure for actuating the valve spool of the control valve is generated in a conduit section which communicates with two annular grooves in the two cylinder sections separated from each other by the piston and adapted alternately to be closed off from the above mentioned conduit section. This conduit section communicates through throttles with the exhaust conduit. The annular groove located in that cylinder section which is defined by the annular piston surface and the cylinder end wall faced thereby communicates through a preloaded check valve with the exhaust conduit.

Power generating means

Abstract: UTILIZING THE NATURAL FORCES OF OSMOSIS INHERENT IN NATURE A POWER GENERATOR IS PROVIDED INCLUDING A POROUS CONTAINER HAVING A SURROUNDING INTERNAL AND/OR EXTERNAL SEMIPERMEABLE MEMBRANE AND CONTAINING A SOLUTION OF RELATIVELY HIGH MOLECULAR C ONCENTRATION SELECTIVE TO SAID MEMBRANE, WHICH CONTAINER IS MOUNTED IN A CHAMBER INTO WHICH A SOLVENT IS INTRODUCED, SAID SOLVENT FLOWING BY OSMOSIS THROUGH SAID SEMIPERMEABLE MEMBRANE INTO SAID SOLUTION CONTAINER, THE RESULTING INCREASED LIQUID VOLUME IN SAID CONTAINER FORCIBLY EXTENDING AN ASSOCIATED PISTON TO PRESSURABLY ENGAGE AND COMPRESS THE AIR OR OTHER FLUID IN AN ADJACENT PRESSURE CELL TO CRETE PRESSURE THEREIN PROVIDING A SOURCE OF POTENTIAL POWER FOR ANY DESIRED PURPOSES.