Abstract: The invention relates to a filter with automatic cleaning using a hydraulically actuated sprinkling device. According to the invention, a carriage carrying tubes is driven by a hydraulic double-acting actuator. The working chambers of the hydraulic actuator are connected by off-take pipes to the cleaning liquid distributing circuit. Switching members control through the medium of electrically controlled valves the selective entry of the cleaning liquid into the off-take pipes. The device according to the invention can be used in an installation where air filtering is necessary, such as for example an air conditioning installation.

Abstract: A shade roller having a chain operated mechanism at one end thereof for controlling the position of the shade on the window, and means for maintaining the chain operated mechanism against a bracket to help insure proper positioning and operation of the said mechanism.

Abstract: There is disclosed a spot-type disc brake having a non-rotating brake carrier to receive the brake torque with brake shoes disposed on both sides of the brake disc. A yoke or frame embraces the disc and is movably guided in the brake carrier and held without clearance by resilient means. The frame transmits the operating force of an actuating device to the brake shoe disposed on the side of the disc remote from the actuating device. The frame is rigidly supported at and movable with respect to three guide points on the brake carrier. A biased spring is disposed between the brake carrier and frame. The spring .[.tensions.]. .Iadd.forces .Iaddend.the frame .[.at.]. .Iadd.against .Iaddend.its guide points and .Iadd.the spring force .Iaddend.acts on the frame at a point distant from the three guide points.

Abstract: An apparatus for rolling chain link fence including an endless belt including a free loop portion and with the endless belt moved in a particular direction and with the movement of the endless belt producing rotative motion in the free loop portion, and with progressive portions of the chain link fence fed into the free loop portion and with at least the free loop portion of the endless belt supporting the progressive portions of the chain link fence to have the individual links of the chain link fence collapse against each other to provide for a tight configuration of the chain link fence within the free loop portion, and with the rotative motion of the free loop portion of the endless belt producing a rolling of the progressive portions of the chain link fence with the individual links collapsed against each other to form a roll of chain link fence with a tight configuration and a small diameter.

Abstract: A derailleur serves to change the speed of a chain driven vehicle by moving a change-over frame having a tension and a guide pulley, the change-over frame being formed of a single plate and provided with a chain holder positioning radially outwardly of the guide pulley and keeping engagement of a driving chain therewith. Interaction between the change over frame and chain during the shifting of speed is substantially reduced. Chain position is maintained by means of a chain holder reducing chain interference with the change over frame. The chain may be removed with a minimum effort without special tools.

Abstract: An arc-shield supporting structure of a vacuum power interrupter is disclosed which comprises a hollow cylindrical supporting means having a turnover end portion embedded in the inner wall of the insulating envelope, and a connecting means one end of which is fitted over the supporting means while the other end of which is fixed to the arc-shield member.

Abstract: The shade assembly for use in a lighting fixture is characterized by a knockdown construction so that it may be easily disassembled for purpose of storage or transport. The shade assembly is in the general form of a regular polyhedron and includes a set of at least three flat trapezoidal windows arranged in a closed figure with their short sides on top and their long sides on the bottom. A base member is centrally disposed in the region above the windows. There are also a set of at least three ribs, each rib extending along the juncture of two of the windows and having its upper end removably secured to the base member. Each window is removably secured to the two adjacent ribs.

Abstract: A head covering having the general appearance of a turban and made from elastic fabric so as to fit securely in a snug manner about the head. Liner components are of a fleecy material to partially fill the interior of the head covering and thereby compensate for the wearer's loss of hair to render the appearance of a head covering worn over a full head of hair.

Abstract: A prosthetic heart valve including a supporting structure comprising a substantially semi-circular base or armature of semi-rigid but somewhat flexible material with two upwardly projecting struts. The armature and struts may be encased with plastic or other suitable material; and are covered with soft flexible material including a strip which connects the free ends of the semi-circular base to form a complete ring. A membrane of biological or biologically acceptable material is shaped about the supporting structure so as to define a cylindrical orifice having lips which overlap, over a significant part of their inside surfaces, to provide a complete and effective closure against and under the force of back-flow. When said lips open the flow is relatively unobstructed. The soft strip of material which completes the armature ring permits the valve to respond more readily to movements of the heart while the semi-rigid section provides adequate support for the valve.

Abstract: An improved process for orthopedic implantation of a prosthesis where the prosthesis has a polymer coating on substantially the entire surface of same that is to be affixed to the bone by bone cement, the polymer coating being substantially completely polymerized and exhibiting a virtually pore free outer surface. After preparation of the bone cavity, a bone cement, preferably a self-curing acrylic is inserted into the bone cavity, after which the precoated prosthesis is properly positioned therein. The polymeric coating on the prosthesis should be compatible with the bone cement to achieve a chemical bond therebetween. A precoated prosthesis is also disclosed and claimed.

Abstract: A dispenser (10) for use in a flush tank of a toilet is disclosed. The flush tank has a first water level (17) during quiescent periods and a second water level (18) when the toilet is flushed. The dispenser (10) includes a housing (11) having a top (11a) and bottom (11b). The housing (11) defines a reservoir (12) having an inlet (13) proximate the top (11a) and an outlet (14) positioned lower than the inlet (13). The reservoir (12) holds the product to be dispensed, the product dissolving in water and forms a solution. A first valve means (16) for regulating flow of water from the flush tank into the reservoir (12) through the inlet (13) is provided. The first valve means (16) is responsive to changes from the first water level (17) to the second water level (18). The second valve means (24) regulates flow of solution out of the reservoir (12 ) through the outlet (14).

Abstract: The invention discloses a closure and hinge device that automatically releases and lowers a toilet seat, or the seat and its associated lid together, when the flushing handle of a commode or toilet is actuated. The device includes a releasable hinge-closing mechanism having a spring-biased latching lever and a dampening device mounted to the toilet lid, the device being positioned to be engaged by the latching lever. When the latching lever is actuated by the flushing of the commode, the seat or the seat and lid together are released and will move downwardly in a controlled manner by means of the dampening device. A latching pawl is located between the lid-hinge member and the seat, whereby the seat and lid are coupled together when in a raised position so as to be lowered together upon being released.

Abstract: A bubble-type shower door adapted to be pivotally mounted symmetrically about its vertical center axis to open and close a shower door opening of the same contour, the door being concave rearward and preferably having a rearward projecting diverging rim portion, and a stop flange projecting laterally from the rim on one side of the door.

Abstract: A toilet seat cover position monitoring device in the form of an attachment to the inside surface of a cover. Upon the cover being moved to the upper position permitting access into the toilet bowl, a first light begins to blink. After a set period of time, a buzzer will begin to sound. Deactivation of both the first light and buzzer will occur upon the toilet seat cover being moved to the lower position covering the opening of the toilet bowl.

Abstract: An adjustable-sized, readily assembled and readily disassembled baby crib made up of a series of plastic tube sections and plastic tube fittings. An invertible bottom portion is useful per se as a small short crib and, when inverted, is useful as a base portion of a taller playpen type of crib. This bottom portion has a planar assembly, a series of identical vertical tube sections, from upper sockets of the planar assembly, and a first generally rectangular assembly. In the playpen-crib the bottom portion is inverted and an upper, second generally rectangular assembly substantially identical to the first generally rectangular assembly and is connected to the long vertical tube sections.

Abstract: Mechanism for maintaining the shape of a floatation sleep system, such system including a bladder having flexible walls defining a chamber adapted to be filled with fluid and a marginal perimeter edge support for such bladder. The shape maintaining mechanism comprises a sheet of flexible, dimensionally stable material. The sheet is attached to the underside of the bladder along a substantial portion of opposed marginal edges so that it extends, in intimate contact, from one edge, around the adjacent marginal perimeter support, across the top portion of the bladder, around the opposite marginal perimeter support to the other edge. Such sheet is thus constrained to oppose the fluid forces on the marginal perimeter support and maintain the shape of the floatation sleep system.

Abstract: A wild bee nesting domicile comprising a strip assembly of a flexible backing sheet to which is secured a matching pleated strip, the strip assembly being rolled or wrapped about itself so that the tips of the pleats are in contact with the backing sheet to form closely spaced bee nesting bores. A backing member is secured to the roll to close one end of the nesting bores as preferred by the wild bees. The domicile may be rolled into circular or oblong form, or may comprise a stack of such strips.

Abstract: A process for the level exhaust dyeing of polyester fiber textile material is accomplished by dissolving unfinished disperse dyestuff synthesis material in as high a concentration as possible in an organic solvent miscible with water. This solution is forced into an aqueous liquor already at a dyeing temperature of 90.degree. to 140.degree. C. and already circulating through the polyester fiber textile material. Dyeing of the material then occurs in the usual manner.

Abstract: An insole support plate disposed on the last post, the insole support plate having a toggle mechanism which permits the support plate to be moved heelwardly an adjustable amount of distance, said support plate and toggle mechanism being arranged on a frame which is pivotable with respect to the last post to facilitate loading of an upper on a last by an operator of a shoe lasting machine.

Abstract: In a tack seat lasting machine the wiper plates (90) first effect an "advancing+inwiping" movement and thereafter an "inwiping only" movement, while a central wiping member (76), about which the wiper plates pivot, advances only. To achieve this motion, the member (76) is supported by an arcuate projection (78) which is accommodated in grooves (83) formed in the wiper carriers (88), the center of curvature of the projection and grooves coinciding with the axis of the wiper plates. Thus, the central wiping member is always brought to the same "back tack" position (but the shoe can be adjustably positioned relative thereto by varying the fore-and-aft position of the heel band (20)). The nail pattern is adjustable, without affecting the back tack position, by limiting the stroke of the cylinder controlling the operation of the wiper assembly.

Abstract: An abrasive scrubbing pad device combined with a wringer mop in which the scrubbing pad when not in use is automatically placed in a physical position which does not interfere with the normal mop function of the mop by an automatic pivoting action brought into operation by actuation of the crank handle of the wringer mop. When the crank handle of the wringer mop is moved to the position where the mop head is functional for mopping purposes, the scrubber pad is pivoted out of the way, and when the actuating handle is operated to retract the mop head between the wringer rollers during a squeeze-out operation, the scrubber pad is pivoted into its operating position. The scrubber pad may be incorporated into the mop when originally asssembled or may be added to the mop at a later time. The scrubber pad structure is formed so that the scrubber pad itself may be replaced in the support structure when the pad has been rendered no longer useful by virtue of wear.

Abstract: A buffing pad retainer is provided for retaining an annular buffing pad in operable engagement with the bristles of a rotating annular floor machine brush. The retainer is a truncated conical disk having a depending cylindrical coaxial disk portion. In operation, the conical disk fits in the bore of the annular rotating brush, while the depending cylindrical coaxial disk fits in the bore of the annular buffing pad.

Abstract: A horizontal mount is provided having opposite side portions and central structure for attaching the lower end of an elongated upstanding support member thereto disposed generally normal to a plane extending between and along the mount opposite side portions. A pair of depending arms are provided and pivot structure pivotally supports the upper end portions of the support arms from corresponding opposite side portions of the mount for independent swinging of the arms about generally parallel axes extending along the mount opposite side portions between extended downwardly and outwardly divergent positons and retracted generally parallel positions disposed generally normal to the aforementioned plane. The free end portions of the arms have fluted rollers journaled therefrom for rotation about axes generally paralleling the first mentioned axes and spring structure is operatively connected between the arms independent of the mount yieldingly biasing the arms toward the extended positions thereof.

Abstract: A method and a device to clean up oil spills or similar substances. Sorbent material for oil or similar products is blown out by means of an air current on to the oil via a spreading duct through a spreading opening. The sorbent material is brought to sorb the oil and oil and sorbent material is sucked up by means of a suction opening via a suction duct to a receptacle.

Abstract: An automatic floor cleaning machine includes a unitary, self-contained and propelled, power driven body mounting from front to rear in a normal cleaning direction of travel: a propulsion mechanism including drive wheels and guide wheels for dry tracking on the floor surface to be cleaned, a scrubber mechanism including a pair of rearwardly disposed, vertically articulated counter-rotating magnetically and floatably mounted brushes for wetting and cleaning such floor surface, a vacuum mechanism including a vertically and horizontally articulated quick-detachable squeegee for drying of and proper tracking on the cleaned surface, and a combined mechanical and electrical control system operatively associated with each of such propulsion, scrubber and vacuum mechanisms, for convenient actuation by a walk-behind operator to control actuation of such machine.

Abstract: A filter cleaning device for purging filters made of porous material employs a tank containing pressurized air and a flow conduit communicating with the tank. A shield mounted on the flow conduit is shaped to engage the filter whereby the pressurized air is suddenly released into an interior chamber of the filter upon actuating a flow valve. An extensible member such as a spring is mounted inside the conduit and has a air flow diverter attached to its lower end so that, upon the sudden rush of air, the flow diverter spreads the air outwardly and radially toward the filter medium and the extensible member gradually extends so that dust is purged substantially from all parts of the filter.

Abstract: A clamp structure especially for use in applications in which space conditions do not permit any projecting parts such as plastically deformable ears, and in which outwardly extending hooks adapted to engage in apertures are used to mechanically interconnect the clamp structure; to enable tightening of the band about an object to be fastened, cold-deformed pressed-out embossments are provided in inner and outer band portions, which extend generally in the circumferential direction so that each pressed-out embossment remains integral at least on both sides thereof, where the tool-engaging surfaces thereof are able to withstand very large tightening forces in the circumferential direction which permit a secure tightening of the clamp structure.

Abstract: The present invention provides a conduit clamp comprising means for securing a conduit such as a hose to another structure, a pair of jaws arranged to be clamped around a conduit, means on one side of a first jaw arranged to engage pivotally with complementary means on the corresponding side of a second jaw, means for closing the jaws into clamping engagement with a conduit which closing means comprises an open sided recess in one jaw, a locking pin mounted in an aperture in the other jaw and a lever pivotally attached to the locking pin, the arrangement being such that when the lever is moved to a first position the locking pin is released from and then pivoted away from the recess and when the lever is moved to a second position the locking pin is moved into the recess and then locked thereinto.The clamp of the present invention is particularly envisaged for sub-sea operation such as in oil drilling but it can be used for mining and industrial applications which are not underwater.

Abstract: A three-tape type zipper is disclosed which comprises first to third tapes, a first slider for fastening the first and second tapes and a second slider for fastening the first and third tapes. One end of the first tape and one end of the second tape are connected to each other and one end of the third tape and the other end of the first tape are connected to each other so that the first tape serves as a common counterpart to the second and third tapes. The other ends of the second and third tapes are kept free. The first and second tapes are fastened together by moving the first slider toward the second slider, whereas the first and third tapes are fastened together by moving the second slider toward the first slider.A bag-shaped article with the three-tape type zipper secured thereto is also disclosed which comprises a body with an opening formed thereon through which things are inserted.

Abstract: The invention comprises safety belt fastening means of the type having a locking tongue slideably engageable with a locking device. The locking device includes a locking flap releaseably engageable with the tongue, and release means for lifting and releasing the flap from engagement with the tongue; according to the invention, blocking means are provided which retain the locking flap in a raised position when the belt is unfastened, which resist initial releasing action to increase the necessary force for unfastening the belt, and which urge the locking flap into close engagement with the tongue on fastening the seat belt. The blocking means includes a blocking flap which coacts with the locking flap, and biasing means acting on the blocking and locking flaps.

Abstract: A high performance lateral transistor may be fabricated by first providing a monocrystalline semiconductor body having a principal surface and where the desired transistor is a PNP transistor, a buried N+ region with an N+ reach-through connecting the buried region to said principal surface. The collector region of the transistor is formed into the surface by blanket diffusing P type impurities into the desired region. An insulating layer is formed upon the top surface of the semiconductor body. An opening is made in the insulating layer where the groove or channel-emitter contact is desired. An etching of a substantially vertical walled groove into the monocrystalline semiconductor body using the patterned insulating layer as the etching mask. An N base diffusion is carried out to produce as N region around the periphery of the opening in the body. Oxygen is then ion implanted into the bottom of the groove to form a silicon dioxide region at the bottom of the groove.

Abstract: A self-stringing jet device which is compact and easy to string up includes a body, a yarn inlet section, a movable venturi and a cylindrical baffle located at the outlet end of the jet. The venturi may be moved from a string up position to an operating position between positive set points engaging the movable venturi located within the jet.

Abstract: A device is described with which a gas check can be squarely placed onto the shank of a cast bullet in a bullet sizing apparatus. The device is a gas check seating body with a laterally located slot so as to fit into the apparatus while partially enclosing a push rod below its head while resting on a shelf. The head of the push rod rests on the gas check seating body and supports an ejector rod located in the bore of the swaging die with an upper end so located that a gas check can be conveniently placed thereon. A bullet shank can then be forced into the gas check so it will squarely fit onto the bullet.

Abstract: A scraping tool more particularly intended to rough-hew surfaces coated with a primer and set up in a frame comprising at least two lateral walls and a face of a plane taken the form of the surface to rough-hew and supplied with an opening in which the sharp steel blade forming the scraper is placed so as to project of the face transversely to the displacement axis of the face on the surface to rough-hew, wherein the blade is mounted in a plane perpendicular to the plane of said face.

Abstract: A roll for use in a printing operation and a method of making same is disclosed. The roll includes a tubular mesh sleeve which is covered with an elastomer composition, such as a Buna-N rubber. The composition includes discrete fibers, such as nylon fibers, which are substantially uniformly dispersed in the composition. The sleeve is stretched over a metal mandrel and the composition, with the fibers therein, is extruded onto the sleeve to form a seamless covering which is vulcanized to the sleeve. The mandrel is removed and the sleeve with its vulcanized covering is then bonded to a metal core by a suitable adhesive, such as an epoxy adhesive, and the outer surface of the covering is ground to raise a nap of the fibers and cleaned to remove any foreign matter not anchored to the coating.

Abstract: A hydraulic accumulator comprises two-halfs shells, the diaphragm therebetween defining two cavities. One cavity contains presssurized gas and the cavity receives hydraulic fluid under pressure. The two-half shells are held together by a mechanical element, such as a belt which has been previously prestressed to a tension selected according to the maximum pressure to which the accumulator will be subjected. The use of the prestressed mechanical element changes the dynamic stresses ordinarily found in a hydraulic accumulator to static stresses, thus minimizing the occurrence of creeks and failure of the device.

Abstract: A jet engine compressor stage puller engages the lip of each disk and spa section of a jet engine compressor, and the end of the compressor shaft. A guide bar has a central threaded hole through which a bolt is threaded. A cup integral with the bolt engages the end of the compressor shaft. A pair of guide rods pass through slots in the guide bar, the slots being symmetrical about the central threaded hole. Shoes attached to the ends of the guide rods engage the lip of each disk or spacer section to be removed. As the bolt is rotated a force is exerted to pull the shoes upward, and thus loosen the disk and spacer stages without danger of damage to compressor parts or hazard to personnel.

Abstract: Apparatus for use in welding end-to-end a pair of annular members such as pipes has first and second annular clamps for encircling and clamping the respective pipes. One of the clamps is supported by the other for axial, transverse, and rocking movements relative to the other clamp while the two pipes are clamped so as to enable the confronting ends of the two pipes to be located in a predetermined relationship prior to being welded together and then maintained in such relationship during welding. Clamping forces are applied on the pipes by radially adjustable pressure members spaced circumferentially about the clamps. The clamps are swingable conjointly from a vertical, operative position to a horizontal position in which the assembly and adjustment of the pressure members is facilitated.

Abstract: An apparatus is provided for assembling pallets which includes an assembly table which is pivotable on an axis, supports for supporting a plurality of first deck boards, and a displaceable support for holding up the underside of the pallet when the table has been inverted, the displaceable support being displaceable to an out of the way position to permit the pallet to drop from the table when assembly has been completed.

Abstract: A method of assembling a rigid wire element for driven rotational movement including attaching a rotational element to a drive means with the rotational element having a transverse bore therethrough slightly larger in diameter than the rigid wire element diameter. A pivot element is located spaced from the rotational element and has an aperture slightly larger in diameter than the rigid wire element diameter. The rigid wire is formed having at one end thereof a relatively straight portion having at one end an integrally formed stop element and at the opposite end a terminal end portion formed at an acute angle relative to the straight portion. The opposite end of the rigid wire element has a U-shaped portion having two legs interconnected by a center section.

Abstract: A scheme for accurately and quickly axially positioning a rotatable member such as the axles of a differential or a shaft supported impeller of a centrifugal pump within a housing or similar support for rotation therein with predetermined axial bearing clearance which is independent of the dimensional variations of the member and support is disclosed wherein a deformable spacing element is associated with each thrust carrying bearing with the adjacent bearing and spacing element being held axially captive between the shaft and a corresponding disc which is slidable relative to the housing and with one disc axially aligned and limited in sliding movement on one common direction opposite the direction from which the rotatable member is positioned by engagement with the housing. Typically there are two discs, one limited in movement toward the interior of the housing and the other limited in movement by the means of encapturing the rotating assembly.

Abstract: A method of forming an axle with hollow spindles which are each capable of supporting a rotatable hub having a wheel and tire mounted thereon. Each hub would include an intermediate cavity which is sealed to define with a wall of the spindle a reservoir for inflation air for the tire. Inflation air is supplied to the spindle at a region axially inwardly of the hub at a predetermined circumferential location thereon. The steps of forming include providing each of the spindles with an outer cylindrical surface at the region. Air passages are formed in the wall of the spindles communicating the intermediate cavity of the hub with a radially extending passage at the outer cylindrical surface. Each of the spindles is welded respectively to the opposite ends of the central portion of the axle.

Abstract: In the disclosed method for fabricating corrugated microwave components, a billet assembly is formed of electrically conductive plates sandwiched with chemical etching sensitive spacer material and clamped together. An inside surface is formed in the billet and a mandrel inserted. An outer contoured surface is then formed on the mandrel-billet assembly. The outer surface is then plated to a desired thickness. The mandrel is removed and the spacers chemically etched away leaving the finished component. With the disclosed method, microwave device fabrication for frequencies including 100 GHz and higher is possible.

Abstract: In a sodium sulphur cell, improved protection of a cathode current collector is obtained by isostatically pressing graphite foil or flakes onto the surface of the collector, which surface is preferably roughened or coated with an intermediate conductive layer such as a nickel-chromium alloy or a conductive carbide providing a rough surface.

Abstract: Apparatus and a method are presented for the paired connection of sheet piles with claws, the piles having either Z-shaped cross-sections or U-shaped cross-sections. The machinery is divided into two general sections having a common axis. One pile to be joined is positioned in one section against a first alignment edge with a claw on the common axis, and the other pile to be joined is positioned in the second section against a second alignment edge with a claw on the common axis. The piles are then joined together to form a paired or "threaded" connection.

Abstract: A method and apparatus for fabricating a plurality of electrical harnesses is disclosed. Each electrical harness includes at least one connector defined by a housing with insulation displacement type contacts loaded therein. The apparatus sequentially feeds sets of connectors to a first station wherein each set includes a plurality of housings joined together by integral, severable connecting tabs. Each set of connectors is then moved to a second station and wires are inserted into the aligned contacts. Additional functions such as drawing lengths of the wires, forming loops of differing magnitudes in the wires and removing insulation from the wires may also be performed by the apparatus. At the completion of the desired functions, the apparatus is actuated to remove the connecting tabs from between the housings thereby forming a plurality of individual harnesses. The individual harnesses are then ejected.

Abstract: A razor blade assembly comprising a blade disposed between skin engaging elements adapted in operation to engage a surface being shaved ahead and behind, respectively, of the blade, the blade being movable relative to the elements in response to forces encountered during a shaving operation, the blade assembly having pivot mountings thereon for pivotal attachment to a razor handle, whereby the blade assembly, as a whole, may be pivotally movable on a handle in response to forces encountered during the shaving operation.

Abstract: A razor handle assembly comprising a grip portion, a head portion at one end of the grip portion having first and second shell bearings mounted thereon, the shell bearings being adapted to receive a razor blade assembly for pivotal movement on the handle, and a spring-biased plunger disposed in the head portion and extending between the first and second shell bearings, the plunger being reciprocally movable, the free end of the plunger being adapted to engage an underside cam portion of the blade assembly to exercise a bias on the blade assembly and thereby urge the blade assembly to a given position on the shell bearings.

Abstract: Apparatus for separating individual conductor elements in a multiple-conductor flat ribbon cable including a rotatable cutting element for cutting the insulating sheathing of the cable along each of the score lines running between the individual conductor cores. The cutting element is provided with a plurality of protruding arcuate cutting edges each interrupted by a shorter indrawn non-cutting edge. Further provided is a cable support element adapted to press a cable inserted into the apparatus against the cutting edges, but not against the indrawn edges. When the indrawn edges face the cable support element, a feed-in and feed-out gap is provided for easy insertion and removal of the cable.

Abstract: An improved hand knife 20 of the type used for trimming meat with a rotary gear-driven ring-like blade 34 guided by a ring-like housing 30. The blade is retained by a partial peripheral flange 90 of the housing and a pivoted retaining shoe 36 secured to the knife hand piece 22. A securing screw 40 and an adjustable abutment 80 retain and position the shoe against the blade. The arrangement allows convenient blade changing. A handpiece 22 has asymmetrically flared recesses 56, 130, 132 adjacent the blade for promoting discharge of product particles that tend to accumulate. The shoe and housing substantially cover gear teeth 42 of the blade.