Abstract: Method for cutting heavy wall steel tubing. The tubing is notched and cut through along a vertical axis but the blade is narrower than the interior diameter so as to leave the side walls uncut. A side wall is preferably notched during the first cut. Thereafter, a second blade is driven horizontally through the side notch to complete the cut.

Abstract: In preparation for reclaiming and recycling the material of construction of a plastic bottle, the friction-fitting base, if any, and bottle cap can be separated from the bottle body by cutting through the cap and base. The cap and base are cut in a plane in which the bottle's longitudinal axis lies. Alternatively, two cuts are made in parallel planes that are also parallel to the bottle's longitudinal axis.

Abstract: A method of cutting a hole in the wall of a pliable tube in which the tube is flattened and is held with the walls touching each other and in which a plug is cut in one of the sidewalls while the tube is in this flattened position.

Abstract: A pipe shearing device comprising a carriage supported slidably by a pair of spline shafts, a drum cam disposed in parallel with the carriage and engaging a pair of follower rollers of the carriage in its cam rail under a holding condition, a rotary drive means connected through a gear train to said spline shafts, a pair of rotary blades provided respectively on a pair of spline bosses which are supported by said carriage and in engagement with said spline shafts, a pair of arms provided on said carriage and adapted to open or close freely, chucks provided to counter to the pair of arms and a pipe chuck mechanism composed of lower blades provided in the chucks respectively and having an arm drive mechanism imparted, so that while the carriage is making a reciprocal movement produced by the revolution of the drum cam, the chuck mechanism grips or holds the pipe during such section of the forward movement of the carriage that the carriage speed is in synchronism with the pipe feed speed, while one of the rotary

Abstract: A manual tool for cutting a polymeric endless power transmission belt body and method of cutting employing such a tool are provided wherein the belt body has a plurality of endless V-belt elements fastened in spaced side-by-side relation by a common endless structure to define alternating projections and grooves in the belt body and wherein the tool comprises, a cutting knife for cutting the endless structure to define a plurality of endless belts each having at least one belt element, a support which is adapted to be disposed in a stationary position and has the cutting knife fastened thereon at a fixed location, and means for supporting and guiding the belt body during cutting with the supporting and guiding means being supported on the support and with the knife cooperating with the supporting and guiding means to provide precise cutting through the structure at the base of a particular groove upon moving the belt body relative to the knife with the knife in cutting engagement with the structure.

Abstract: A pipe coupling, which renders it possible to connect branch pipes (24) to a feed-pipe (1) without requiring the flow in the feed-pipe to be shut off. In a cylindrical guide passageway (5) of one of two coupling parts (2a,2b) embracing the feed-pipe a piston (4) is located, which is provided with a passageway (10) for fluid connection between the feed-pipe and the branch pipe. The piston is provided with an internal knife (9) which upon rotation of the piston cuts up material out of the feed pipe to form the opening to the passageway and projects the cut-up material into the guide passageway (5) to assist in anchoring the coupling in place.

Abstract: A continuous base of sheet material carrying on its one surface a number of successive rows of laterally spaced loops raised from the one surface is advanced continuously or intermittently along an arcuate path with the loops directed outwardly of the arcuate path. Each of the loops of one of the rows is cut on one of its legs at a two different points by reciprocating a cooperating pair of relatively movable cutting members two times along a given reciprocating path while the one row of loops is in the reciprocating path of the cutting members along the arcuate path.

Abstract: Apparatus draws a continuous length of shrink tubing from a reel, cuts off a section, and advances it onto the terminated end of a lead carried by an adjacent conveyor. This is accomplished by shear blades integral with jaws which close on the end of the tubing to sever a section and contain it and shape it between the jaws. The jaws move vertically in a plate which is then advanced horizontally toward the lead. A feed clamp which descends with the jaws draws the continuous length forward then releases vertically as the jaws depart and a stationary clamp grips the tubing while the jaws and clamp return over the tubing for the next shearing and advance operation. Above motions are effected by levers and a slide driven by followers riding in cam grooves on discs carried by a single shaft. The end of the lead with tubing section thereon is transported laterally through a hot air duct type heater having slotted walls which permit passage of the lead therethrough.

Abstract: Fibrous board transition parts are produced on the job site from standard lengths of preformed fiberboard duct units. Transition parts are interposed between linear runs of duct pieced together to change direction of the duct work. The transition parts, sometimes referred to as elbows or bends, can be easily fabricated on the job site by modifying standard lengths of preformed linear duct by cutting and removing pie-shaped sections from the duct. The modified duct can be bent inwardly to form a one-piece arcuate transition part wherein the outer wall section remains intact and provides structural strength to the transition part. The seams are secured with structural adhesive tape wrapped around the transition part.

Abstract: A hand tool for cutting a textile cot from an associated mandrel, method of making such tool, and method of utilizing the tool and removing such a cot from the mandrel are provided wherein such tool is in the form of a pliers-like instrument having a special cutting blade.

Abstract: A tapping apparatus and method for making connections to pipelines and vessels while they are in service and contain fluid under pressure. The tapping apparatus and method includes an explosively driven punch that is operated to penetrate the pipeline. A tensile force is applied to retract the punch, and allow the fluid to pass from the pipeline through the apparatus and into the service connection.

Abstract: An apparatus and method for cutting a flexible hose which has an axially extending helically wound reinforcing wire during continuous forming of the hose around a mandrel are provided wherein the apparatus comprises, means for determining length increments of the formed hose, a pair of cooperating cutters for cutting the formed hose based on each determined length increment with the cutters comprising a rotary cutter for cutting the flexible portion of the hose and a chisel cutter for cutting the wire of the hose and with the cutters being operatively connected to the determining means, a first and a second fluid powered cylinder for operating the cutters, first connecting means operatively connecting the first cylinder to the rotary cutter, second connecting means operatively connecting the second cylinder to the chisel cutter, and control means for sequentially actuating the cylinders in response to each determined length increment of the formed hose.

Abstract: A remotely operable device for cutting sample pieces from the walls of an irradiated component while the component is submerged in a pool of water to shield the operator from radiation.

Abstract: A pipe shearing device provided with a holder means which is shifted laterally by means of a follower connected therewith and engaging in a cam groove of a drum cam, a pair of rotating blades slidably mounted on spline shafts, the first blade of the pair being arranged to cut the surface of the pipe to form a slit during its rotary movement to make it easy for the second blade of the pair to produce a cut pipe of the desired length by cutting through the slit during its opposite rotary movement, a clamp device which grips or holds the pipe unmovably while the pair of rotary blades are in motion, and a motor connected to the drum cam and the spline shafts through a gear train.

Abstract: An apparatus for removing the wire-reinforced inside rim cores of automobile tires and the like so as to permit shredding for fuel or other use of the remaining carcass, such apparatus principally featuring axially aligned reciprocative action tubular cutters, associated tire positioning and centering mechanism including conjointly actuated centering arms, an annular tire support platform that yieldably supports the tire at a level initially above the lower cutter, and a centering cone member that precisely centers the tire as the upper cutter approaches cutting engagement with the tire, and further featuring an upper cutter assembly that carries a stripper that presses the severed or partially severed cores through the interior of the lower cutters and in the process thereof completes the severance of tire wall material over the edge of the lower cutter.

Abstract: A ram operated tube cutoff apparatus of the type employed for severing successive lengths of tubing emanating from a source such as a mill includes a transversely reciprocating notching blade for producing a stress relieving notch in the periphery of the tubing, and a severing blade having a thickness less than that of the notching blade for severing the tubing through the notch. The tubing is clamped during the notching and severing operation by reciprocably mounted die jaws each of which comprises a pair of spaced apart, parallel clamping members between which the notching and severing blades may travel. The clamping members are provided with blade supporting parallel surfaces in the opposing spaces thereof for closely receiving the severing blade therebetween to prevent deflection of the severing blade during the cutting process.

Abstract: A strap cutter is secured to the top structure on an oil well casing and as the discharge pipe supporting a submersible pump is withdrawn, the cutting head of the strap cutter engages with and cuts the straps which secure the pump power cable to the discharge pipe. The strap cutter is manually guided into place but employs the upward motion of the discharge pipe string to supply the cutting force. The method comprises the use of the upward motion to accomplish the cutting step.

Abstract: A Jack-O-Lantern forming method for cutting facial feature openings (14) in a pumpkin (12). At least one pumpkin die element (26) having a closed contour sidewall element (32) is provided. The sidewall element (32) has a lower edge (36) adapted for contiguous interface with the pumpkin outer surface contour (16). Additionally, the pumpkin die element (26) has an upper edge (38) adapted to be impact loaded for displacing the pumpkin die element (26) through a wall (22) of the pumpkin (12). The die element (26) is impacted on the upper edge (38) and displaced through the wall (22) to provide a plug element which is removable and is contoured in the form of one of the facial feature openings (14). Through use of a number of differently contoured die elements (26), a wide variety of facial feature contour openings (14) may be provided in a minimal time reference frame.

Abstract: Hollow cylinders of relatively rigidized paper are perforated in closely spaced circularly extending, axially spaced rows by perforating adjacent ones of the rows from opposite sides on the cylinders. Apparatus for perforating the cylinders uses a fixed rolling shoe and a rotating drum each of which carry needles to effect perforation. The method and apparatus are especially effective for perforating paper cylinder cigarette mouthpieces.

Abstract: An apparatus for and method of severing a continuous flexible reinforced elastomeric conduit supported on a plurality of elongated rigid mandrels disposed in connected end-to-end relation is provided with the apparatus and method enabling cutting through the conduit at each end of each mandrel so that each mandrel has a length of conduit therearound which is approximately equal to the length of the mandrel.

Abstract: Apparatus including two types of cutting means or roller cutters and shears for cutting a channel box for a fuel assembly for a nuclear reactor and method therefor. The roller cutters and shears are located in the lower portion of a casing having inserted thereinto the channel box from which the fuel assembly has been removed, with the shears being located beneath the roller cutters. The roller cutters continuously cut the channel box axially thereof, while the shears shear the axially-split portions of the channel box in a direction intersecting the center axis of the channel box. Means for outwardly expanding the axially-split portions of the channel box is provided between the roller cutters and the shears. Means for downwardly moving the channel box in the casing is inserted in the casing. Means for drawing off coolant from the casing to clean the latter is connected to the upper portion of the casing.

Abstract: Method and apparatus for inverting a torroidal article such as a tractor tire, comprising: a base assembly; a first frame assembly pivotably rearwardly attached to the base assembly; a second frame assembly pivotably attached to a forward portion of the first frame assembly; a tire holder attached to the second frame assembly; and grappling means for holding an edge portion of a tire to be inverted relative to the base assembly. The tire holder is rotatable to permit the removal of a rim portion of the tire on the tire holder by a cutting blade fixed on a boom attached to the apparatus. Rotation of the tire holder is actuated by a hydraulic motor, and hydraulic cylinders are used to pivot the first frame assembly and the second frame assembly. The apparatus is made portable, with a minimum of necessary external support systems, such as a hydraulic fluid pump. The article thus produced has a generally cylindrical shape, smoothed by clamping means, making it useful as a feed bunk for livestock.

Abstract: A thermoplastic corrugated drainage tube comprising annular peaks and valleys and a plurality of drainage openings internally cut about the circumference of each valley, the openings in each valley aligned with the openings in successive valleys along helical lines described by said openings. The method of forming the drainage openings comprises placing a cutting tool in the interior of the tubing and rotating the tool while moving the tubing axially past the tool. The cutting tool comprises a body having a plurality of radially projecting cutters spaced equidistantly about the cutter body and means for rotating the tool.

Abstract: Corrugated tubing is advanced along its axial path by rotatably driven lead screw members the screw threading of which is in meshing engagement with the corrugations of the tubing, the lead screw members being in pairs with the screw threading of the members of each pair being of opposite hand and the lead screw members each pair being rotated in opposite directions. The lead screw members of each pair present outwardly directed cutters which are synchronized substantially simultaneously to intersect the tubing thereby, in perforating the tubing, to restrain the tubing against rotation thereof about the axial path.

Abstract: A method and a device for interrupting or reducing a media flow through a tubular pipe, involving removal of two opposed circumferential wall portions of the tubular pipe by means of two mainly parallel pistons, thereafter moving a third piston mainly mutually perpendicularly to the direction of travel for the pistons parallel piston and the length axis of the tubular pipe to a position mainly extending through the parallel pistons, the tubular pipe and the opposed openings of same, the third piston means being arranged with expanding devices, which, after completed movement of the third piston, are expanded to reduce, or interrupt, the internal cross-sectional area of the tubular pipe.

Abstract: An apparatus for perforating the minor diameter or inner corrugation of a transversely corrugated thermoplastic drainage pipe. A plurality of perforations are simultaneously formed in the inner corrugations of the pipe by reciprocally moving heated punches radially into the pipe, removing the punches and then translating the pipe to another position for the next punching step. In an alternative embodiment, the punches are carried by a rotating ring which positions them opposite an inner corrugation and a cam device drives the punch radially into the pipe.

Abstract: In order to produce an optical cable core composed of a plurality of optical cable elements stranded together, each element is produced by longitudinally slitting a stable tube, inserting at least one optical fiber into the tube through the slit, and causing the slit to close behind the fiber so that the fiber lies loosely in the tube, and the resulting elements are then stranded together to form the core.

Abstract: Described is a method of making fluid-issuing openings through the wall of flexible plastic members, particularly fluid conduits, by forming each opening through a small radius of curvature portion of the conduit wall while the respective wall portion is of curved oblong shape in cross-section, such that during use of the conduit, it assumes a circular shape, thereby increasing the radius of curvature of the wall portion and reducing the cross-sectional area of the outer part of the opening formed therethrough. The method is particularly described for producing linear-source water irrigation emitters which have a smaller sensitivity to clogging, which are easier to clean, and which have a smaller sensitivity to pressure variations in the water supply line.

Abstract: Corrugated tubing is advanced along its axial path by rotatably driven lead screw members the screw threading of which is in meshing engagement with the corrugations of the tubing, the lead screw members being in pairs with the screw threading of the members of each pair being of opposite hand and the lead screw members of each pair being rotated in opposite directions. The lead screw members of each pair present outwardly directed cutters which are synchronized substantially simultaneously to intersect the tubing thereby, in perforating the tubing, to restrain the tubing against rotation thereof about the axial path. There is also disclosed a method of producing the lead screw members with the outwardly projecting cutters mounted thereon.

Abstract: Making insulation sleeves from binder containing fibrous material, including integrated method and apparatus features for dividing a continuous blanket or web of fibrous material into individual lengths, winding individual lengths of fibrous blanket upon a multi-part separable mandrel, heating the mandrel to cure the binder in the inside surface layer of the sleeve, separating the sleeve from the mandrel, bringing the outside surface of the sleeve into contact with a heated surface to cure the binder in the outside surface layer of the sleeve, delivering the sleeves to a curing oven in which the sleeves are advanced and rotated, trimming the ends of the sleeves, and axially slitting the sleeves.

Abstract: An apparatus for cutting openings at arbitrarily selectable intervals into a pipe which has a smooth inside or outside surface or a transversely corrugated inside or outside surface comprising a knife disposed inside or outside said pipe, and a movable element whose movement is responsive to a signal to move the knife and pipe wall into mutual contact so that the knife cuts into the pipe wall. Disclosed herein is an apparatus which cuts an opening through the surface of a smooth inner pipe disposed within an outer pipe having transverse corrugations. Also disclosed is an apparatus whose knife is disposed exteriorly and is employed to cut openings into the exteriorly disposed transversely corrugated pipe. The application further discloses an apparatus comprising a pipe forming machine, an apparatus which cuts a hole in a pipe from within the pipe and an apparatus which cuts a hole in a pipe from outside the pipe.

Abstract: Apparatus comprising a pair of endless conveyors arranged on an aligned line with a space therebetween, one of which runs intermittently and the other continuously; a lifter arranged between the conveyors to freely move up- and downwards; a gripper arranged above the lifter to freely close and open its claws; and a cutter arranged immediately below the gripper and attached freely swingable and integral to a cutter plate being freely movable in a direction perpendicular to the direction at which a cylindrical package is conveyed; wherein the front end of the package is brought and stopped above the lifter by means of the intermittently running conveyor; the front end of the package is a little lifted and pressed by the lifter against the claws of the gripper; the gripper closes its claws to grip the packaging material of the package at the upper side thereof and then to hang the package when the lifter returns to its original position; the tip of the cutter is horizontally thrust into the packaging material be

Abstract: A system for notching tubes to facilitate their joinder to other tubes or rods, in which a first portion of the notch is formed by a rotary cutting action extending progressively inwardly into the tube side wall and then outwardly in an arcuate path, and the second portion of the notch is formed by a plunging, shearing action which simultaneously punches the entire second portion of the notch out of the wall of the tube. The apparatus for forming each of the notches preferably includes a pair of die halves which together define a tube receiving passage intersected by a tool receiving passage, and a cutting tool positioned in the tool receiving passage. The tool is provided with a substantially axially extending rotary cutting edge for forming the first portion of the notch and a shearing edge for punching out the second portion of the notch when the tool is plunged through the wall of a tube positioned in the intersection of the tube and tool receiving passages.

Abstract: A means and method of installing emitters in irrigation tubing, wherein a core assembly dimensioned for ready insertion in a thinwall irrigation tube is provided with internal rollers which are confronted by fixed external rollers positioned to function through the walls of the irrigation tube so as to retain the core assembly in a fixed position as the tubing is moved between the internal and external rollers; the core assembly including an anvil periodically engaged by an external radially movable cutting tool to form in the irrigation tube a series of emitter receiving perforations; the core assembly also including a fork member for spacing the perforated wall of the irrigation tube from the opposite wall thereof to facilitate reception of emitters forced therein by an external mandrel; the anvil and fork and their respective cutting tool and mandrel adapted to be spaced at preselected distances depending on the required emitter spacing.

Abstract: An apparatus for cutting into and stopping the flow of fluid in a plastic pipe including a cutting blade that is forced downwardly into a pipe by a hydraulic force. The blade is slightly larger than the internal diameter of the pipe and thus when located within the pipe stops the flow of fluid in the pipe. The apparatus is constructed so that the cutting, flow stopping and the consequential withdrawal of the blade operation is carried out without loss of fluid from the pipe. Part of the apparatus is left on the pipe and encapsulated to complete the operation.

Abstract: A process for perforating plastic tubes, in particular thin-walled corrugated tubes, by a punching or cutting operation wherein the plastic tubes are subjected to a direct or indirect treatment by a cooling fluid prior to the punching and cutting operation. The process is performed by an apparatus comprising a guide structure and conveying device for conveying the plastic tubes, and further comprising punching or cutting members, while spraying devices are provided for effecting the above-mentioned cooling treatment.

Abstract: Tube slotting machine for cutting series of transverse slotted openings in flexible corrugated tubing comprises main framework with tube supporting and conveying structure connected thereto for guiding tubing through machine. Cutting structure is adapted to engage tubing as it travels through machine and to cut transverse slotted openings therein. Cutting structure includes plurality of primary cutter blades, and equal number of spaced apart secondary blade pairs are arranged with one primary blade located between each pair. Each secondary blade has curved portion that complements curvature of tubing. Secondary blades are positioned next to exterior of tubing as it moves through machine along its path of travel, and primary cutter blade is shifted across its associated secondary blade pair so that primary blade penetrates tubing and sweeps across secondary blade pair to thereby cut slivered portion from tubing to provide transverse slotted opening therein.

Abstract: A cut-off die set is disclosed for use in a cut-off apparatus of the type in which continuous length of tubing or other elongated stock emanating from a tubing mill is severed into lengths as the tubing emanates from the tubing mill by means of a cut-off die set mounted within the cut-off apparatus. The cut-off die set is adapted to be clamped to the tube so as to move therewith during severing of the tubing by a ram operated cut-off blade descending vertically to shear the tubing. The present disclosure involves a improvement to a notching mechanism often included in such cut-off apparatus in which a horizontally reciprocated blade notches the upper portion of the tubing just prior to severing by the main cut-off blade so as to eliminate dimples in the severed tube cross section.

Abstract: A method for manufacturing perforated plastic pipes, in particular corrugated thermoplastic pipes of which the wave valleys are perforated by at least one punching member, to which a velocity is imparted in the direction of conveyance of the plastic pipes, which equals the rate of conveyance of these pipes. During the punching operation the punching member or members retain substantially a perpendicular position with respect to the plastic pipes.

Abstract: A tool for making a radial cut in the annulus of a ring, including a support holding a circular saw and a pair of jaws pivoted to each other and to the support for clamping the ring and moving it across the saw to form a cut through the annulus of the ring.

Abstract: The instant invention relates to a system for the forming and trimming of tubular articles, such as aluminum and steel cans. The irregular edge at the open end of the can is trimmed by internally and externally positioned knives with respect to the can, with the internally positioned knife having a diameter less than 0.0015 inch shorter than the inside diameter of the can.

Abstract: A tube perforating device for forming outlet openings in a tube, such as a plastic tube, having discharge openings for passage of air, or the like, where it is desired to diminish the sound of the discharge to a minimum, and the method of accomplishing such opening formations by multiple perforations with perforating members spaced as desired and having ovoid heads to permit perforations of the walls of the tube and withdrawing the head of the perforating means through the perforations, drawing the peripheral margins of the opening outwardly, leaving the inside wall of the tube smooth, thus diminishing turbulance therein, and said device having an adjustment permitting a selective penetration of both walls of the tubing, transversely, with just the point of the penetrating means perforating the bottom wall, forcing said peripheral margin outwardly on the bottom perforation, and withdrawing the said head through the upper wall penetration, again moving the peripheral margin outwardly, providing pairs of openin

Abstract: An endless elastic band is severed from a tube of resilient material while the interior of the resultant band is being engaged by tensioning fingers which can be manipulated to deliver the band in at least partially expanded condition.

Abstract: A tube cutoff apparatus of the shear knife type is provided with an improved knife holder to reduce the likelihood of fracture. The knife holder and the tube clamping jaws are formed to provide a nesting relationship at the full cut position which increases the blade penetration depth without sacrificing blade support.

Abstract: A device for manufacturing corrugated plastic tube by subjecting an internally unsupported corrugated plastic tube, at a temperature between 30.degree. and 70.degree. C, to the simultaneous action of at least two punching members in one or in two corrugations.A device comprising a guide for corrugated plastic tube, and punching means with an operating member for simultaneously acting upon at least two punching members spaced a short distance from each other.

Abstract: A cutting tool is provided with a plurality of circular cutting blades of varying predetermined thicknesses to shear sections from rings made of precious metals. Each blade is formed with a notched perimeter to provide a pair of blade cutting edges. The blades are mounted on a spindle for rotation therewith, while the spindle is rotatably mounted in a plurality of cutting blocks which are affixed to a base in an alternating arrangement with the aforesaid blades. The cutting blocks define cutting edges so that rotation of the spindle causes the blade cutting edges formed by the notched perimeter to come into a simultaneous shearing relation with the cutting edges of the two adjacent cutting blocks. Further rotation of the spindle will shear out a section of a ring interposed in the notched perimeter of the blade. The tool is further provided with removable trays to catch sheared pieces of precious metals. Rotation of the spindle is accomplished through a conventional crank handle.

Abstract: Parallelepipedic packing containers are made and filled in succession by passing a continuous web of packaging material over a forming device which converts the web into tubular form with an overlapped longitudinal seam. The tube is then filled with the intended contents, e.g., a liquid and is then divided off into individual packing containers by first pressing the tube transversely at longitudinally spaced intervals along broad zones and the opposite sides of the flattened tube are heat-sealed to each other along two narrow sealing regions close to the opposite base lines of the flattened zone while the remaining portions of the flattened zone remain non-sealed.

Abstract: A can slitting device is provided for cutting slits in cans, such as beverage cans, typically for producing ornamental objects. The device comprises a lever pivotally mounted on a vertical member and carrying a blade to cut the can upon urging the lever, and a cylindrical support extending from the support and adapted to extend into a can, the blade being received in the slit as the can is cut.

Abstract: A metal door frame has trim molding applied to its flanges by the aid of separate clips. Each clip interfits an aperture in the flange and a notch at the flange edge. The aperture and the notch are punched in the flange so that the spacing thereof from the corner of the flange is constant whereby alignment of the clips is assured notwithstanding lack of critical dimensional control of the flange.

Abstract: A roll splitter apparatus is described for splitting a roll of paper or other sheet material using a cutter blade which moves substantially horizontally toward the roll core. A pair of generally horizontal extending holding arms are provided with hooks on the ends of such arms which engage a shaft extending through the core of the sheet roll to hold such roll while the cutter blade is moved radially inward toward the core to cut the roll. The cutter blade is driven by a fluid cylinder and has guide members which slide along the holding arms to guide the movement of such blade. The holding arms and blade are raised and lowered by means of another fluid cylinder in order to accommodate rolls of different diameter. A knife guard is provided which covers the cutter blade in its retracted position, such guard being raised and lowered by cams provided on the blade.