Abstract: A motor-curler unit for the automatic application of curlers to hair to be treated includes a motor and a curler made of a suitable material, for example a pressed plastic material. The curler includes two coaxial elements which are mated to one another and are adapted for engagement with a corresponding part of the motor in such a manner that a first curler element can be fixed with respect to the motor casing, while a second curler element torsionally joins the relative motor shaft such that by operating the motor, rotation of the second element, rotating respective to the first element, winds the hair around the first element. Thereafter, when the motor is stopped and the curler released, the curler will rest in the hair with the hair lock still wound around it.

Abstract: A coin agitating attachment for use on rotary coin transport discs fed by a coin hopper for coin-dispensing and counting machines. The attachment can be made in several configurations of elastomeric materials each characterized by at least a superficial resiliency of limited stiffness such that any point of impact with or by a coin presents a yieldable contact surface which is nevertheless sufficiently rigid to repel and drive the coins while retaining the original shape or configuration.

Abstract: A membrane structure having a frame constructed of radial supports that extend outward and downward from a common apex to the base. These support members are usually curved semi-arches or have a curved bight, are indirectly attached to each other at the apex and are normally secured directly to the base to oppose outward thrust of the lower ends and to anchor the structure. Outward thrust can also be opposed by an auxiliary circumferential tension member near the base. These supports can be precurved before erection or formed by "bowling" straight members during assembly and/or erection.The membrane cover supported by the frame is fabricated to curve inwardly between, at least, the curved bights of the supports to decrease membrane vibration, enable it to carry heavy external loads, oppose deflection of the supports and thus add stability to the structure.

Abstract: A fluid diverting assembly is constituted by a structural body having a nozzle from which a main stream of fluid is issued as the fluid passes therethrough, a pair of opposed control chambers positioned adjacent the nozzle and on respective lateral sides of the stream of fluid, a pair of side walls outwardly diverging in a direction downstream of the nozzle with respect to the direction of flow of the main fluid stream, and control apertures respectively communicated to the control chambers. An interceptor mechanism is provided for alternately adjustably closing any one of the control apertures for deflecting the direction of flow of the main fluid stream issued by the nozzle.

Abstract: A flow regulator is disclosed for controlling liquid flow, for example, from a supply source to a receiving tank according to the liquid level in the tank. Specifically, a fluid interaction device communicating with the receiving tank causes a fluid pressure signal to be developed in response to departure of the liquid in the tank from a predetermined level. A differential pressure responsive valve adjusts liquid flow from the supply source to the receiving tank in response to the fluid pressure signal. Several embodiments and other features including a bypass for enhancing stable flow and a preferred valve structure are disclosed.A beverage dispensing system incorporating the aforesaid flow regulator is also disclosed. A cold carbonated liquid is continually circulated past dispensers from a pressurized chill tank having a carbon dioxide atmosphere. The flow regulator admits further liquid to the system from a supply source whenever liquid is tapped from the system by the dispensers.

Abstract: The purpose of the invention is to provide a pilot-valve-controlled safety valve for venting excess pressures without allowing any noxious gas to exhaust to atmosphere in the vicinity of personnel.This purpose is achieved by the provision of a safety valve and pilot valve combination with a connection from the pilot valve to an exhaust duct of the main safety valve. Control of the exhaust rate from the pilot valve is effected by the provision of a divergent nozzle at the downstream end of the pipe leading from the pilot valve.The invention is of particular value when applied to a storage vessel for natural gas or a natural gas pipeline.

Abstract: A pilot controlled membrane valve for ventilating containers or the like comprises a valve housing having a first valve seat between the inlet and outlet of the housing. First valve means, movable between a closed position engaging said first valve seat and an open position, include a first membrane extending transversely through the housing and defining with the latter to one side of the first valve seat a valve chamber, which is connected by an overpressure passage means to the inlet. The valve includes further a pilot valve having a second seat, second valve means including a second membrane and being movable between a closed position engaging the second valve seat and an open position, a second outlet, means biasing the second valve means to the closed position and chamber means under atmospheric pressure surrounding the biasing means, in which the cross-section of the second valve seart and that of the second outlet is greater than the open cross section of the overpressure passage means.

Abstract: A free delivery controlled return valve, of the type employed in fluid power hoisting apparatus, which controls the speed at which a load is lowered as a function of load magnitude. An improved valve structure is disclosed which overcomes false load signals, such as those generated when the hoisting apparatus' lift cylinders are fully extended against a stop, and which thus permits the load platform to descend at an appropriate speed. An improved fluid sonic muffler is also disclosed.

Abstract: Improvements in a check valve are disclosed. The check valve contemplated is of the type used to halt fluid flow in a fluid-carrying pipe system, and comprises an annular seat adapted to be mounted in the fluid line, a head-mounting yoke, and a head carried by the yoke and adapted to slide axially into and out of fluid-sealing engagement with the seat. One improvement comprises a pair of valve sleeves extending, respectively, axially upstream and downstream of the valve seat; each valve has a mouth adapted for mating connection with adjacent fluid-carrying pipe structure. Each sleeve terminates adjacent the valve seat in a diagonal flange formation, and a clamp including a V-shaped collar fits over the sleeve flanges so as to urge the sleeves toward the valve seat and toward one another. A gasket having a U-shaped cross section provides a fluid-tight seal between the sleeves and seat.

Abstract: Discloses a guide means for an indicating check valve and leak indicator utilized for indicating the position of a valve closure means relative to spaced apart inlet and outlet ports. The invention involves the use of an elongated cylindrical valve chamber having a cylindrical plug member slidably mounted therein and containing a first magnetic means. A second magnetic indicating means situated outside the valve housing and outside the valve chamber moves responsive to the axial movement of the valve closure in said valve chamber. The valve closure means is guided by means of a pin sliding in a groove in the wall of the valve chamber. This guiding means prevents the cylindrical plug valve from spinning around inside the valve chamber during the axial movement between open and closed positions.

Abstract: An upstream fluid chamber adapted for fluid flow in a given direction is interconnected to a downstream fluid chamber by a plurality of individually actuatable digital valve elements disposed in a plane substantially transverse to the given direction so that the pressure drop across each valve element is substantially the same. The valve elements are disposed so the fluid from the upstream chamber passing through the valve elements converges in the downstream chamber to dissipate the vena contracta. The areas of the valve elements are weighted so the smaller areas follow a geometric progression while the larger areas deviate from a geometric progression. Preferably, at least the two larger areas are the same size. The valve elements themselves each have an orifice, a plug, and means for maintaining the plug in one of two positions. The plug seals the orifice in the one position and lies outside of the fluid stream in the static fluid region in the other position.

Abstract: A long-distance heating conduit comprising one or more tubes which carry the heating medium, are laid in the conduit and are surrounded individually or jointly by at least one layer of heat-insulating material and are covered by at least one cover foil which extends in a closed path round the tube or tubes and is provided with holes.

Abstract: A hose structure which is useful as a transitional piece for a connection between two elements of different diameters. The hose has a tapered bore with an oppositely tapered sleeve of deformable material outwardly of the sleeve interior to form a substantially cylindrical outer surface over which the remaining portions of the hose structure are applied. If desired, buoyancy material can be included in the hose structure so that the hose will be buoyant and float in water. The method includes applying an elastomeric liner around a tapered mandrel, applying the tapered layer of deformable material to form a cylindrical outer surface, applying at least one reinforcing layer to the cylindrical surface, applying a cover over the reinforcing layer then vulcanizing the structure to form an integral unit.

Abstract: A blow plate and blow tube assembly. The blow tube conveys core-making sand from the blow plate to a cavity in a core box for forming a sand core utilized in metal casting. The blow plate has a discharge passage with female threads. The blow tube has a body portion and a tip portion for directing the sand from the blow plate into the core box. The body portion of the blow tube has male threads axially therealong and the blow tube is threaded into the passage in the blow plate and extends from the blow plate for engaging the core box. A nut is threaded onto the male threads of the body portion of the blow tube and is disposed between the blow plate and the core box. The blow tube is made of plastic material and includes a shoulder or sleeve portion between the male threads on the body portion and the conically-shaped tip portion. The conically-shaped tip portion has spaced annular ribs thereabout for forming seals with a conical seat in the core box.

Abstract: A portable sawmill system comprising at least three wheeled, independently movable modules is disclosed. The modules are independently maneuverable to a land site having a ready source of logs to be processed and are arranged in a preselected geometrical configuration adjacent one another and the source of logs. A log from the source is received on the first module and debarked. The debarked log is moved axially and transversely off the first module and onto a second module. A plurality of saw means are carried by the second module to form boards from a log being processed. A third module is located at the output side of the second module and is adapted to receive and further process the boards formed on the second module.

Abstract: A woodwool producing machine comprises a cutter wheel which is supported with its axis vertical and which has a frusto-conical rim at its outer periphery. The rim tapers upwardly and has a circumferential array of slots formed in it, a cutter assembly, which comprises a pair of cutters for cutting woodwool strands from timber stock, is mounted in each slot. Several timber feed magazines are positioned at spaced intervals around the circumference of the rim and are adapted to support and locate pieces of timber stock against the outer surface of the rim with their grain generally tangential to the rim. The cutter wheel is driven in operation so that strands of woodwool are cut by the cutters from pieces of timber located against its rim. The woodwool is directed to the interior of the wheel, through the slots, and falls onto a collector.

Abstract: A method of and apparatus for removing bark from a log or cant. The cant is fed via an infeed section which eliminates limbs to a two-stage drier section in which a radial frequency generator with plate electrodes creates an electrical field in the cant to heat the moisture therein by dielectric means. In the second stage a concentrated electrical field is applied to the bark area by oval electrodes to produce a gas buildup between the cambium and the bark to cause partial separation of the bark. The drier section is followed by a three-stage debarking section, with brushes in the first stage for removing loose, large bark pieces, with crusher heads in the second stage to loosen, raise and flake the remaining bark without damaging the wood, and a final brush section for removing rough edges and create a smooth finish.

Abstract: An expandable shopping bag utilizes an open mouth pouch, fabricated from a flexible material, having a girth encircling strap removably secured thereto which permits the pouch to be utilized in small and large item receiving capacities. The strap ends are removably affixed to the pouch adjacent the open mouth portion thereof facilitating its use as a shoulder strap, complementing a pair of string-like handles partially contained within opposed passageways shorter than half the perimeter of the marginal edges of the pouch.

Abstract: A tire and wheel rim assembly wherein the wheel rim includes adjacent to at least one bead seat a circumferentially extending groove and the tire bead has a radially and axially projecting extended toe portion which is axially and radially located within said groove. The toe is flexible in a direction substantially perpendicular to its length and substantially rigid in the direction of its length and provides an effective bead lock to retain the tire bead in position on the rim.

Abstract: In a continuous compression casting process for making a casting slab such as steel, the problem of the occurrence of slippage; between the casting slab and the rolls is effectively overcome by a control means for releasing or gradually decreasing the braking action of the braking rolls.

Abstract: A method for manufacturing a thermally highly stressed, cooled component, more particularly, a blade for turbine engines. A component of the above-mentioned type has a central supporting core formed of a solid material and has connected thereto several short, radially outwardly projecting ridges which, in turn, carry an outer shroud concentrically encompassing the supporting core, and which is made of a through-porous material, whereby the supporting core, ribs, and outer shroud are cast in a single piece.

Abstract: A method and device are disclosed for aligning up a pouring mold tube in a continuous casting machine. The device has a mold insert portion having a pair of parallel faces which mate with the vertical parallel internal walls of a mold tube. A vertical alignment means is attached to the top of the mold insert portion and is adapted to indicate when the mold insert portion and hence the mold tube is in a vertical position. A radial and horizontal alignment means is also attached to the mold insert portion and is adapted to indicate when the mold insert portion and the mold tube are radially and horizontally aligned. The method includes the steps of inserting a mold insert portion of an alignment device between the vertical parallel walls of a mold tube and adjusting the elevation of the adaptor plate supporting the mold tube such that the alignment device is aligned vertically, radially and laterally.

Abstract: A heat insulation layer is provided on the exterior surface of a port liner. The port liner is installed in the exhaust port passage upon casting of a cylinder head by filling a moulding material in the cavity of the port liner to serve as an exhaust port, mounting preformed and cured separate layers of moulding material on the exterior surface of the port liner and using the port liner with a mass of a moulding material therein and separate layers of a moulding material thereon as a core for casting an exhaust port passage and a heat insulation layer of the exhaust port.

Abstract: A casting device with a mold section attached to a fixed platen, a mold section attached to a movable platen, a drive unit to move the movable platen in relation to the fixed platen, coupling rods connecting the movable platen to the fixed platen when the two mold sections have fully or closely approached each other and hydraulic pressure mechanisms capable of closing completely the mold sections, and keeping them closed, against the high internal injection pressure. Each platen, on the side removed from the mold sections, is provided with a rigid frame and with a number of hydraulic rams, together forming the above-mentioned hydraulic pressure mechanism, distributed between the platen and its rigid frame and the coupling rods are disconnectably connected with the circumference of both rigid frames so as to connect these frames with compressive stress or tensile strength by means of the double-acting rams, when the mold sections have fully or closely approached each other.

Abstract: A rotary regenerator construction comprising a ceramic core adapted to rotate upon its central axis and a ring gear surrounding the periphery of the core for purposes of driving the core rotatably and a yieldable compliant ring sandwiched between the ring gear and the periphery of the core to prevent stresses in the core caused by differential rates of expansion of the core and the ring during operation of the regenerator in a gas turbine engine and during processing of the regenerator and the regenerator drive ring.

Abstract: A combined storage tank and heat exchanger unit for heating water including a watertight tank having a water inlet in the lower portion thereof and a pair of water outlets in the upper portion thereof. The wall of the tank is in the form of a double wall jacket having a hot refrigerant inlet at the top portion thereof and a hot refrigerant outlet at the bottom portion thereof. A cylindrical heat barrier is mounted inside the tank and spaced a short distance from the inside surface of the jacket wall to thermally isolate a relatively small amount of water in the tank in direct contact with the inner surface of the jacket. A heat barrier disc is mounted in the tank and extends horizontally across the interior thereof to thermally isolate the water in the top portion of the tank from the water in the bottom portion thereof. The water outlets communicate with the interior of the tank on opposite sides of the partition to provide heated water at two distinctly different temperatures.

Abstract: Heat is generated by combustion of coal or like carbonaceous fuel reactant dissolved in molten salt. The generated heat is transferred to steam by an alternating sequence of direct contact heat exchanges of the salt and steam with a common heat transfer medium.

Abstract: Two identically folded strips enclose an intermediate space accessible at e edges of the strip, and the fold cavities opening to the outside of the strip structure are closed off at the strip edges and covered by outside cover plates over their central portions, so that one medium may be caused to flow through each of the sets of outside fold cavities and a third medium through the intermediate space. The third medium flows countercurrent to the direction of flow of the other two. Modules of four such matrices utilize inlet and outlet ducts so that the two or four matrices in a compact modular structure can be structurally repeated in accordance with the number of modules desired in the particular application. The inlet and outlet ducts have tapering flow cross-sections.

Abstract: The hydrocarbon, hydrogen and carbon monoxide concentration of a gas is reduced by reacting these constituents in the gas with oxygen in the presence of a fragmented permeable mass of combusted oil shale.

Abstract: In producing shale oil from a water-productive leached zone of a subterranean oil shale the reservoir pressure is counterbalanced to restrict water production. A generally vertical heated channel is formed by injecting steam into a lower location while producing fluid from an upper location until a steam zone extends substantially between the locations. Oil shale is pyrolyzed within the heated channel by flowing gaseous fluid, which contains noncondensable components and is heated to an oil shale pyrolyzing temperature, upward through the channel. Shale oil is recovered from the fluid flowing upward through the channel while the composition, pressure and rate of flow of that fluid are adjusted to maintain a selected ratio between its oil phase and aqueous phase components.

Abstract: Subterranean formations having temperatures between about 250.degree. F. and about 700.degree. F. are acidized by introducing a substantially anhydrous acid precursor through a well and into the formation, wherein the precursor hydrolyzes in situ to generate a hydrohalic acid. The acid precursor is a normally liquid, halogenated hydrocarbon having one or two carbon atoms per molecule which is thermally stable under the high temperature and pressure conditions encountered prior to hydrolysis.

Abstract: A storage tank such as those used to store petroleum products has a floating roof for the top closure and a seal between the roof and the tank sidewall for sealing the space and allowing relative movement therebetween. A conduit system is provided for the delivery of foam to the seal area in the event of a fire so as to extinguish the flame which is normally present in the seal area. The foam delivery system includes a conduit which preferably is flexible and functions both as a roof drain conduit and a foam delivery conduit which by a valve mechanism selectively allows draining of water from the roof or the delivery of foam to the roof.

Abstract: A lawn perforating machine for forming rows of holes in the ground comprises a perforating roller which is adapted to roll on the ground and whose peripheral surface carries perforating tubes mounted for pivotal movement about axes extending parallel to the axis of the roller so that from the beginning to the end of their contact with the ground their axes remain substantially perpendicular to the ground. Part of the periphery of the roller is enclosed by a guide plate to intercept plugs of earth formed by the perforating tubes. In one embodiment a spring comb is disposed behind the roller to produce clean holes even in wet ground.

Abstract: An implement assembly includes two elongated frame portions with respective coupling members that are linked to one another. Either frame portion can be leading or trailing and in a preferred arrangement, the leading frame portion has tined soil working members that work overlapping strips of top soil while the trailing frame portion has tined tools that work subsoil in non-overlapping paths. A common transmission can be fixed to either respective gear box that rotates the members and the tools. In either arrangment, the transmission is connected to the driving gears for both the members and the tools which can be rotated at different speeds from that of the members. A ground engaging wheel can be positioned at either side of the center of the assembly to bear on ground that is located between neighboring tools and/or members. The member can work paths of soil having different widths from those of the tools.

Abstract: A cultivating machine (FIG. 1) having a frame (1) for mounting of the machine on a tractor, and having arms (34) on which angle drives (6) for the cultivating tools (26) are mounted, resiliently joined thereto by way of arms (29) and connectors (33, 35, 36). A transverse shaft (7), by way of bevel gears, drives the tool holders (24) for rotation of the tools (26). The transverse shaft directly drives output shafts to which the tool holders are connected.

Abstract: An attachment for tractors including a pair of elongate support members attached at their forward ends to the tractor frame and at their rearward ends to the tractor's three point hitch arms. A blade assembly is carried by the elongate members and is adjusted vertically or inclined transversely to the tractor centerline by adjustment of three point hitch components. The blade of the assembly is also rotatable about a vertical pivot with a locking mechanism provided for the blade. A tractor mounted bracket removably mounts the forward ends of the elongate support members.

Abstract: A hydraulically actuated auger is adapted for mounting on a skid steer vehicle. The auger includes a hydraulic drive motor for driving the main drive shaft of the implement as well as an auxiliary drive shaft interconnected with the main shaft by multiple chain and sprocket drives disposed therebetween. An augering tool is mountable on one or the other of the output shafts of the implement. Use of the appropriate chain and sprocket drive with the hydraulic output of the drive motor permits variable speed settings for the hydraulic auger.

Abstract: This invention is a Well Drilling Apparatus primarily intended for drilling water wells, but also adaptable for other well, or hole drilling activities. The apparatus is particularly characterized by an independent driving arrangement for the drill, accompanied by an independent driving arrangement by which the casing may be turned during the drilling operation for ease of insertion and may accompany the drill into the ground to prevent collapse during drilling operations as well as to enhance the removal of drilled material.

Abstract: A tungsten carbide insert for mounting in a rolling cone cutter comprises a base for mounting in the rolling cone cutter, an end converging to the work surface, and a diamond insert embedded in a portion of the work surface to improve the wear resistance of the insert. Preferably the diamond insert is embedded in the portion of the work surface extending farthest from the rolling cone cutter in which the tungsten carbide insert is mounted. Diamond inserts are provided in carbide inserts on the gage row of a cutter. Diamond inserts can also be used in tungsten carbide inserts on the heel row of a rolling cone cutter for maintaining gage of a hole being bored.

Abstract: A transducer for measuring the load of a vehicle employing an equalizing beam suspension. In an equalizing beam suspension a pair of tandem wheels are supported by opposite ends of a pair of transversely spaced, center-mounted equalizing beams. Each equalizing beam carries one of the transducers which measures the deflection of the respective equalizing beam responsive to vehicle loading. The transducer includes a push rod clamped to the equalizing beam and extending into a measurement block which is clamped to a different point on the equalizing beam. The measurement block contains a strain gauge instrumented cantilever beam against which the motion transmitting bar abuts. Consequently, the cantilever beam deflects responsive to movement of the motion transmitting bar toward and away from the measurement block produced by load induced deflections of the equalizing beams. The measurement block is essentially a plurality of stacked plates, one of which forms the cantilever beam.

Abstract: The magnet system of a top-loading precision balance with electromagnetic load compensation is fixedly fastened in an aluminum alloy frame constituting the fixed link in the parallelogram suspension for the weighing pan. Distortion of the frame under thermal stresses due to the different coefficients of expansion of the ferrous metal of the magnet system and the light metal of the frame is prevented by openings in the frame walls spacedly surrounding the portions of the frame wall fixedly fastened to the magnet system.

Abstract: An improved load cell scale which comprises a load supporting frame pivotally carried upon levers which bear upon a load cell on the frame and, are in turn, pivoted upon fulcrum pins. All pivot pins are journaled in oversized bores formed in the levers so as to rock the pins with a slight rolling motion in the bores under load-induced pivotal action, rather than with rotation about the pin axis.

Abstract: A resistor coded anti-theft system particularly adapted for incorporation as original equipment on a motor vehicle is disclosed. The ignition system is defeated unless an ignition key having both the proper mechanical code and proper code resistor is used to start the vehicle. A selectively destructible fuse device is incorporated in the circuitry to permit determination of the value of the proper code resistor during a final stage of vehicle assembly.

Abstract: A quarter fender and associated support of the type used with a tractor of a tractor-trailer mounted from the frame of the tractor adjacent rear wheels of the tractor. The support for the fender comprises a tube or pipe accommodating at one end a hefty washer welded into the tube and for receiving a bolt for securing the tube against the frame of the vehicle, a nut being provided in association with the bolt for tightening the support to the vehicle frame.

Abstract: Axle mounting of integral power steering is provided by a central adjustable locating pin that prevents lateral movement of the mounting base plate of the steering gear with respect to the axle. The locating pin includes an opening adjacent the slightly oversized hole in the vehicle axle with radially extensible ball bearings positioned in the opening. The bearings are spaced around the pin to provide engagement against the periphery of the wall of the hole. The pin is accurately positioned in the base plate of the mounting bracket by employing a tight fit in a reamed mounting aperture in the bracket. The locating pin includes a central bore having a cam screw including a frusto-conical section on the lower end to force the ball bearings outwardly against the wall of the hole in the axle. The opening for the bearings is filled with high viscosity grease to hold the ball bearings in position during mounting and for lubrication.

Abstract: A system for vibrating the earth in a location where seismic mapping is to take place, including forming a relatively shallow hole in the earth such as a hole 10 feet deep, placing a solid propellant in the hole, sealing a portion of the hole above the solid propellant with a device that can rapidly open and close to allow a repeatedly interrupted escape of gas, and igniting the propellant so that high pressure gas is created which escapes in pulses to vibrate the earth.

Abstract: The present invention relates to a multipurpose apparatus that may be used, for example, as a tree stand or backpack frame or the like. Structurally, the apparatus comprises a main frame structure having a seat pivotably mounted about one area thereof and a back area provided above said seat within said main frame structure. Straps are provided about said main frame structure for enabling the apparatus to be strapped about a tree or other structure, or to be utilized as shoulder straps for supporting the apparatus about an individual when the apparatus is used as a backpack frame.

Abstract: An apparatus for actuating the hoistway doors of an elevator, which comprises a coupling element fixedly arranged at the hoistway or elevator shaft door and a movable electromagnetically actuatable coupling element arranged at the elevator cabin door which, at the region of an elevator landing or storey can be brought into engagement with the fixed coupling element of the hoistway door. The movable coupling element arranged at the elevator cabin door comprises an entrainment member composed of discs arranged at essentially the same spacing from one another. The stationary or fixed coupling element mounted at the hoistway door comprises a comb having prongs which possess an essentially uniform spacing from one another, which spacing is dimensioned such that the discs of the entrainment member, during the coupling action, engage with play between the prongs of the comb.

Abstract: A portable parking brake for use with tandemly mounted wheels of a vehicle including a pair of brake shoes mounted on a central shaft with at least one of the brake shoes being movable horizontally away from the other along that shaft so that each brake shoe can contact the central area of one of the tandemly mounted wheels. Also included is an adjusting means for moving the pair of brake shoes into braking engagement with the wheels to effect the shoes' braking condition.

Abstract: A brake shoe clearance adjusting device in an internal shoe drum brake including a pair of arcuate brake shoes, and a strut of adjustable length extending between the brake shoes and consisting a first strut part, a second strut part having male screw-thread portion thereon at least a part of which being received slidably in a tubular portion of the first strut part, and an adjusting nut engaging screw-thread portion of the second strut part and abutting with the first strut part, wherein a retaining member extends between one of brake shoes and one end of the strut and engages with one end of a shoe return spring whereby a portion of the force of the shoe return spring acts to pull the strut bodily toward the other brake shoe.