Abstract: Disclosed is a multiple heat exchanger system utilizing an inlet manifold to distribute the flow of thermoplastic material from an extruder to the inlet ends of each of the heat exchangers, and a discharge manifold to converge the flow of thermoplastic material from the discharge ends of each of the heat exchangers and to direct the flow to an extrusion die. The inlet and outlet manifolds include a main port in communication with a plurality of passageways within the manifold to allow flow between a main conduit in communication with the main port and a plurality of distribution conduits in communication with each of the heat exchangers. A flow control means positioned at each distribution port includes a sleeve, having a flow space therethrough, axially aligned within both the distribution port and distribution conduit. The distribution conduit includes a plurality of orifices about the circumference thereof in communication with the heat exchanger for the flow of thermoplastic material.

Abstract: A process is disclosed for the formation of pipe comprising one or more layers of thermoplastic resin whereby an annular stream of thermoplastic material is transported through an annular extrusion passageway. The downstream annular portion of the extrusion passageway has a radially movable outer wall. The outer wall is radially moved by heat expansion of a bolt thereagainst to change the thickness of a particular arcuate section of the stream. The thickness of the particular arcuate section of the stream may be further changed through selectively heating by electrical resistive elements an arcuate section of the extrusion passageway to heat the stream of thermoplastic material transported in proximity thereto.

Abstract: An apparatus for the formation of a multiple layered pipe comprising a die housing having a bore therethrough with a mandrel longitudinally supported within the bore by a spider to provide an annular extrusion passageway defined by the inside surface of the housing and the outer surface of the mandrel. The mandrel comprises a series of sequentially positioned annular feed rings for the laydown of thermoplastic material on the inner surface of the main thermoplastic material flowing thereover through the extrusion passageway. The extrusion passageway is constricted downstream of the spider but prior to the annular sequentially positioned feed rings to reunite the thermoplastic material after the flow disruption created by the spider. Also included in the mandrel is a longitudinal passageway in communication with the inlet section of the bore for the transportation of thermoplastic material therethrough to one or more of the annular feed rings.

Abstract: A rotary extruder contains pump rings positioned at opposite ends of the rotor shaft to collect excess thermoplastic melt forced outwardly to the housing ends and to redirect this excess melt to the feed section of the extruder. Redirection of the melt is accomplished by helical grooves located on the inside surfaces of the pump rings having an axial component directed toward the center of the extruder to provide a conduit for the melt. The melt is also directed by a series of angular grooves positioned circumferentially about the rotor opposite the pump rings which rotationally and axially propel the melt as the extruder rotor rotates. The rotor shaft is supported by bearings at opposite ends of the shaft which are offset from the axial center of the bearing housing.

Abstract: A process is disclosed for the coextrusion of a multi-layered tube whereby at least one stream of molten polymer from a single-screw extruder is passed through a die; wherein the stream is divided into two concentric streams which are balanced by varying the area of a restrictor orifice placed in the central stream. Spider lines in the outer molten stream are eliminated by the use of a second restrictor means used downstream of an open chamber for reuniting the melt, which chamber is downstream of the spider legs.

Abstract: The improved dwell and depth attachment includes an elongate housing that is attached to a drill motor and has an output shaft that is movable longitudinally and rotatably in the housing for rotating a drill bit. A drive spindle is connected with the output shaft and extends through the housing. An elongated sleeve encircles the spindle and has an end that is engageable with the work piece. An adjustable depth control located within the housing is connected for movement with the spindle. A first portion of the control includes a threaded interior and has ten circumferentially spaced, radially extending holes therein. The control also includes a second portion that has a threaded exterior mating with the first portion and has ten slots equally spaced about the exterior. The threads are selected to be loose fitting so that the portions of the control can "float" relative to each other.

Abstract: The improved load limiting apparatus includes a chainwheel that is mounted on the hoist drive shaft and adapted to receive the drive chain. The chainwheel includes a hub connected to the drive shaft, an annular clamping member located in juxtaposition to the hub and adjustably attached thereto, and an annular chainwheel rim located in encircling relationship to the hub and clamping member and having a bifurcated flange in frictional engagement with the hub and clamping member, whereby the rim can move relative to the hub and clamping member after a pre-determined torque load is imposed on the rim by the drive chain.

Abstract: The improved power tool includes a housing having a motor located in the housing and a rotatable tool drive shaft projecting from the housing. A torque reaction bar is attached to the housing and is engageable with a stationary object to prevent rotation of the housing relative to a threaded fastener or the like being operated upon. A tool handle rotatably encircles the housing permitting the positioning of the handle in any desired position relative to the housing and, due to the swivel or pivoting relationship, preventing the imposition of torque on the handle.

Abstract: The shaft seal includes at least first and second annular land members that are located on the shaft and toward the housing, an annular spacer member positioned on the shaft between the land members, a generally annular seal member frictionally engaging the housing and located between the land members. The arrangement is such that changes in axial dimension of the shaft will cause repositioning of the seal member and thus maintain an effective seal between the shaft and the housing.

Abstract: The condensation control device includes sensors for measuring system pressure, ambient temperature and relative humidity for computing the saturation temperature of gas in the system. It also includes a sensor for sensing the system temperature which is compared with the saturation temperature to generate a signal that causes the opening of a valve in a by-pass conduit permitting cooling oil to by-pass a heat exchanger. Thus, the temperature in the compressor system is raised above the saturation temperature and avoids the formation of condensate in the system.

Abstract: Clutch-clutch-brake steering unit having hydraulically actuated cylinders for controlling same to control rotation of a track-drive sprocket in a crawler tractor. Specifically, one of the clutch cylinders and a brake cylinder provided in the unit have an inlet-outlet port in common, and are so arranged on a spring-applied-brake, hydraulically-applied-clutch basis that a single pressure signal in the inlet-outlet port alternately operates the cylinders to apply the brake and release the one clutch, to apply the one clutch and release the brake or, by proper modulation, to partially engage either, i.e., slip the clutch or drag the brake to intermediate degrees as desired.

Abstract: Improved exhaust gas recirculation systems for turbocharged gas engines that include an exhaust pipe, a turbocharger connected thereto, and a carburetor connected with a source of gas for the engine. The recirculation system includes an air conduit extending from the turbocharger compressor discharge to a venturi, an exhaust gas conduit that extends from a connection with the exhaust pipe between the engine and the turbocharger to the venturi, a second air conduit that extends from the exhaust pipe to a connection with the first air conduit, and control valves located in the exhaust gas conduit and in the second air conduit. The valves are closed when the engine is being started or idling at no load and open when a load is imposed or when engine rpm's are increased. No pumps, blowers, etc. are needed because the system operates on a differential in pressure created within the system to cause the exhaust gas recirculation.

Abstract: A control means for a variable displacement pump (12) driven by an engine (10) and having a servo-cylinder (78) determining the displacement of the variable pump (12). A charge pump (14) is driven by the engine (10) and supplies charge pressure to the variable pump (12) through an orifice (40). Pilot conduits (42,44) on each side of the orifice (40) sense the pressure drop due to flow and relay the resulting signals to each end of a metering spool (52) in a speed control valve (46), which is arranged to control the pressure in the servo-cylinder (78). A spring (90) biases the servo-cylinder (78) toward an extreme position for the variable pump (12) and opposes the pressure directed to the servo-cylinder (78) by the speed valve (46) in order to provide a smooth transition between the extreme positions for pump displacement.

Abstract: The collet-type drill includes improved clamping means having a pressure foot member that is in engagement with the work piece. The pressure foot member is connected with a drill motor and with a feed means. A collet is operably connected to and movable relative to the foot member, and when actuated, connects the drill to the work piece. A clamp bushing has one end pivotally connected with the collet and encircles a cylindrical sleeve that has a transverse slot extending therethrough. The bushing is connected to the pressure foot member. A clamping piston extends through the sleeve and carries a connecting pin that extends through the slot in the sleeve into the clamp bushing whereby the bushing and collet are movable together in response to movement of the clamping piston to force the collet into holding engagement with the work piece.

Abstract: The improved shut-off apparatus for pneumatically driven tools includes an auxiliary shut-off valve located in the flow passageway. The valve is controlled by a control rod which extends through the air motor into engagement with a latching device. The latching device is held in the latched position with the valve open by a movable weighted control member. The movable weighted control member is responsive to inertia so that as the speed of the air motor decreases due to a torque load imposed thereon, the shaft slows causing the inertial movement of the weighted member to release the latching device permitting the auxiliary shut-off valve to close.

Abstract: The improved grinder of this invention is provided with a non-circular peripheral surface encompassing an output shaft. The non-circular peripheral surface is arranged to receive a mating hole in a grinder wheel guard. The grinder wheel guard is positioned on the grinder by means of a threaded fastener or the like and is sufficiently large to house an appropriate grinder wheel. The arrangement between the non-circular peripheral surface on the grinder and the mating hole in the grinder wheel guard provides a means for transferring any load imposed on the grinder wheel guard directly into the body or housing of the grinder.

Abstract: An improved expander of this invention is used for expanding tubes into tube sheets and flaring the ends extending therefrom, such as is common practice in the manufacture of boilers. The improved expander includes both straight rolls for expanding the tubes and tapered rolls for flaring the tube ends. The rolls are carried by a cage that encircles a tapered mandrel, which when forced through the cage, causes the rolls to move relatively outwardly to deform or expand the tube. The expander also includes a thrust member that has an end that is engageable with the face of the tube sheet and a stop member carried by the cage that engages the thrust member, when the rolls have entered the tubing to the proper distance, to deform the tube the desired amount as well as flaring the ends to the proper position.

Abstract: A manufacturing process for tongue and groove pliers that involves forging plier members with a bend between the nose and handle portions, forging arcuate projections on the members with mating surfaces on the projections. The surfaces having an angular orientation relative to the adjacent plier surface of 90.degree. minus an angle that is less than the supplement of the angle of the bend, and straightening the members so that the mating surfaces, when engaged, tend to urge said plier members relatively toward each other.

Abstract: The improved shut-off apparatus for pneumatically driven tools includes an auxiliary shut-off valve located in the flow passageway. The valve is controlled by a control rod which extends through the air motor into engagement with a latching device. The latching device is held in the latched position with the valve open by a movable weighted control member. The movable weighted control member is responsive to inertia so that as the speed of the air motor decreases due to a torque load imposed thereon, the shaft slows causing the inertial movement of the weighted member to release the latching device permitting the auxiliary shut-off valve to close.

Abstract: The apparatus described herein is for use in a valve including a hollow valve body having inlet and outlet passageways extending into the body and a valve member positioned in the body for movement between open and closed positions. A plurality of orifice members are disposed between the inlet and outlet so that fluid flowing through the valve must pass therethrough. The orifice members are arranged to restrict fluid flow and thus reduce the pressure as the fluid flows through the valve. The orifice members are also arranged so that the inlet to each series of members is through an annular space that is narrower than the smallest of the orifices so that any particle passing through the annular space will pass through the valve. Each inlet is provided with a cleaning member that projects therein and the orifice members are rotatable in the valve body so that the cleaning members pass through each inlet.