Abstract: Steel reinforced tire fabrics are cut with long rigid bar blades, circular disc blades and disc and anvil blades. All of these blades may have an open relatively deep slot spaced close to the cutting edge that creates a resilient cantilevered spring element that includes the cutting edge. In response to cutting forces, the spring element will deflect and form a concave crossover area that improves cutting. A supporting material, particularly a precompressed supporting material, such as a precompressed or stretched polyurethane strip may be inserted into the slot. The supporting material limits or reduces the deflection of the spring element so that the yield strength of the spring element is not exceeded and it returns to its original position when the forces are removed. A precompressed supporting material exerts an outward force on the spring element. A polyurethane strip may be precompressed by stretching it before it is inserted into the slot.

Abstract: Slitting shears comprising two knife shafts which are adjustable in relation to one another and are equipped with at least one knife each are described. Some of the knives are adjustable by means of compression springs and with compressed air in the opposite direction in parallel to the axis of the knife shaft. By correspondingly selecting the tensioning force, a machine tool is created which makes possible the automatic adjustment of the tools, especially knives and spring-loaded knives. Besides the reliable contact of the pairs of knives which is achieved as a result, the machine is made ready for operation in a simpler manner and more rapidly, especially in the case of a tool change.

Abstract: A ticket making apparatus includes a feed mechanism and a perforating assembly set within a housing that has an opening through which tickets are dispensed. The perforating assembly perforates a flexible material to define individual tickets. The apparatus can also include a slicer assembly to slice the flexible material into strips of tickets. The apparatus can also include a printing mechanism for adding print to the flexible material. A method for making tickets includes feeding a flexible material into a perforating assembly and dispensing the perforated material as a plurality of tickets. The method can also include synchronizing the flexible material to the rotation of the perforating assembly, slicing the flexible material into strips of tickets, and printing on the flexible material.

Abstract: Steel reinforced tire fabrics are cut with long rigid bar blades, circular disc blades sand disc and anvil blades. All of these blades may have an open relatively deep slot spaced close to the cutting edge that creates a resilient cantilevered spring element that includes the cutting edge. In response to cutting forces, the spring element will deflect and form a concave crossover area that improves cutting. A supporting material, particularly a precompressed supporting material, such as a precompressed or stretched polyurethane strip may be inserted into the slot. The supporting material limits or reduces the deflection of the spring element so that the yield strength of the spring element is not exceeded and it returns to its original position when the forces are removed. A precompressed supporting material exerts an outward force on the spring element. A polyurethane strip may be precompressed by stretching it before it is inserted into the slot.

Abstract: A slitter cutting element for slitting a sheet of web material has an axially displaceable blade member arranged on a blade carrier. The axially displaceable blade member is biased by an elastomeric biasing member that provides a continuous and uniform contact force with a face of the blade member. The elastomeric biasing member is restrained from axial expansion by being bonded to the blade carrier.

Abstract: Slitting shears comprising two knife shafts which are adjustable in relation to one another and are equipped with at least one knife each are described. Some of the knives are adjustable by means of compression springs and with compressed air in the opposite direction in parallel to the axis of the knife shaft. By correspondingly selecting the tensioning force, a machine tool is created which makes possible the automatic adjustment of the tools, especially knives and spring-loaded knives. Besides the reliable contact of the pairs of knives which is achieved as a result, the machine is made ready for operation in a simpler manner and more rapidly, especially in the case of a tool change.

Abstract: A cutting apparatus for cutting a piece of large-sized, printed paper as large as the multiple of a piece of small-sized paper into the multiple number of pieces of small-sized paper each having letters and/or pictures printed thereon such as name cards. The cutting apparatus has two pairs of parallel-arranged rods rotatably supported in its casing. The first pair of parallel-arranged rods has paired sharp blades fixed thereto at a relatively large interval whereas the second pair of parallel-arranged rods has paired sharp blades fixed thereto at a relatively small interval. The two parallel-arranged rods each of the first and second pairs are separated such a predetermined distance as to allow the paired sharp blades to rub circumferentially on each other. A handle is rotatably fixed to the casing, and operatively connected to the two pairs of parallel-arranged rods for turning the paired rods in opposite directions.

Abstract: A sheet cutter for cutting a sheet by shearing. The sheet cutter has a fixed blade, a movable blade which is movable along the fixed blade, and a receiving element which receives a sheet piece which is cut off from the sheet. The receiving element is structured so as to be movable together with the movable blade as the movable blade moves. The receiving element may be structured such that it is translationally movable in a direction substantially perpendicular to the moving direction of the movable blade.

Abstract: An apparatus for slitting a sheet of web material has an at least one first fixed blade member and axially displaceable at least one second blade member. The axially displaceable second blade member is biased by an elastomeric biasing member that provides a continuous and uniform contact force with a face of the second blade member. The elastomeric biasing member is restrained from axial movement by a bonded ring member.

Abstract: A cutting apparatus in a strong plastic housing having two rotatable slitter blades. The cutting apparatus is mounted on a guide rail for movement by hand across a tightly held sheet of media such as paper, vellum or film. The slitter blades are mounted back-to-back at an angle, and the shafts to which the blades are mounted are positioned in the housing so that their longitudinal axes are not parallel to each other. This offset minimizes the region of contact between the two blades.

Abstract: A knife holder unit combined with a rotary knife pair includes a frame composed of an upper frame part and a lower frame part; and an upper and a lower knife holder assembly supported in the upper and the lower frame part, respectively. Each knife holder assembly includes a bearing shaft composed of a first bearing shaft part having a longitudinal axis and an adjoining second bearing shaft part. The first bearing shaft part is received in a recess of a respective frame part for turning motions therein about the longitudinal axis. A first securing arrangement immobilizes the first bearing shaft part relative to the respective frame part. A rotary bearing surrounds the second bearing shaft part and has a rotary axis which is offset relative to the longitudinal axis to define an eccentricity therewith. A rotary knife is mounted on the rotary bearing.

Abstract: A multi-use cutter is especially useful for cutting standard size paper and card stock into business card sizes. The preferred model of the multi-use cutter will measure six inches deep by fifteen inches tall by fifteen and a half inches wide and will be powered by standard 115 volt alternating current power source. The paper stock is sequentially fed into the cutter and can be collected in catch trays. The starting feed stock size can be varied by simply changing the size of the paper guide. Where the cutters are set to produce an American standard sized two by three and a half inch business card, the starting feedstock can be of any size.

Abstract: A slitting assembly for producing a plurality of "interrupted cut" slits in a large sheet of sport card photos includes a horizontal support track carrying a plurality of individual upper slitting assemblies each including a freely rotatable upper hub, an upper blade concentrically attached to the upper hub, a resilient band circumferentially disposed on the upper hub to frictionally engage the top surface of the sheet being slit, and an upper blade biasing element to resiliently urge an edge of the upper blade against an edge of the corresponding lower blade. The upper blades are precisely parallel to the lower blades to avoid interference with notches provided in the lower blades to interrupt the slits being made. The locations of the notches are selected to compensate for slippage resulting from the frictional engagement.

Abstract: The invention relates to a tenter frame for treating web materials such as woven or knitted fabrics, film or the like, to apparatus for removing a web from a tenter while controlling the web and to a process for removal of a web from a tenter. A pair of endless opposed tenter chains having a plurality of pins thereon engage opposite edges of the web material for holding it as it is treated on the tenter frame. Pinned rolls are provided for engaging and transferring the web material from the pins of the tenter frame with the web taken off of the tenter chains without loss of control over the web. A cutter unit is also be provided for trimming the edges from the web after it has been removed from the tenter chain, and while the web remains under control of the pinned rolls, after which trimmed edges are automatically removed from the pins for discarding.

Abstract: A sheet material cutting mechanism for cutting sheet materials two rotary blades and a mechanism for pressing down a sheet material to be cut. When the motor is started, a screw shaft 2 rotates, and a rotary blade assembly 4 starts to move to the right in FIG. 1 . Then, the roller 12 rotates by friction with a frame 1, and a first rotary blade 10 rotates by the rotation of a roller. At the same time, a second rotary blade 20 also rotates by the frictional force generated between the rubber roller 22 and the frame 1. The sheet material, fed into the sheet material receiving portion 17, is pressed by the rubber roller 22 against the surface 5 of the frame 1 immediately before cutting to prevent lifting or bending of the sheet material, thereby producing satisfactory cutting of the sheet material.

Abstract: A holder for a circular cutting knife for slitting sheet metal, comprising a precision ground mounting shaft for attaching the cutting knife, the mounting shaft rotatably retained within a housing by engaging sets of high precision ball bearings. The ball bearings are located within the housing by a set of precision ground bearing spacers and precision ground bearing retainers. The bearings are preloaded in the housing to minimize longitudinal movement of the mounting shaft during operation. Additionally, the housing containing the bearings is tapered on one surface so that the cant of the knife blade can be adjusted by reversing the orientation of the housing.

Abstract: The invention relates to a circular knife (12) as well as a cutting device (11-15) for cutting materials into webs. The cutting device comprises at least one circular knife (12) arranged on a shaft (11) and characterized in that the circular knife is directly mounted on the shaft, the knife being maintained in the cutting position by means of two spacer rings (13) located on both sides of the knife. The knife is characterized in that, when it is mounted according to the present invention device, it exhibits a suitable flexibility, in order, when operating, to generate a pressure on a lower knife whose variations with respect to a mean value do not exceed 10% in absolute value.

Abstract: A roller assembly for supporting a running web of corrugated paperboard in a slitting apparatus includes a pair of rollers which define therebetween a slot for receipt of a rotary slitting blade. The rollers are mounted on separate rotational axes which are angled slightly with respect to one another so that the axially inner edge portions of the rollers where the blade enters the slot therebetween actually engage the blade edge and the diametrically opposite edge portions of the rollers are maximally spaced to define between the adjacent roller faces a downwardly divergent slot. Roller contact with the blade faces helps prevent paperboard adhesive build up and the entry of scrap into the slot. The downwardly divergent shape of the slot allows scrap which does enter therein to be discharged readily with rotation of the rollers. The roller assembly is adapted to be carried with the slitting blade and automatically positioned with the mechanism used to drive and lock the slitting blade in operating position.

Abstract: A device for machining sheet like material comprises first and second substantially circular machining tools having peripheral machining edges. The tools are each mounted on a shaft for rotation about the shaft axis. At least one of the tools is provided with magnetic means used to force the two tools into continuous contact with each other at a machining nip during operation of the device.

Abstract: A slitter moving mechanism includes an upper and a lower blade unit with an upper and lower blade respectively, the upper blade being movable between a slitting position to slit a web in a feed direction and a retracted position wherein the web can pass between the blades without being slit; a supporting member vertically and laterally movable within predetermined ranges and rotatably supporting the upper blade, a biasing member for upwardly biasing the supporting member and generating a coupling force for laterally moving the upper blade in a separating direction away from the lower blade; and guide member for restraining lateral movement of the upper blade in the separating direction beyond a predetermined distance and for guiding the vertical movement of the supporting member between the slitting and retracted position; the upper blade unit including a lowering device for lowering the supporting member and for generating another coupling force to swing the upper blade into contact with the lower blade, the

Abstract: A device for cutting and/or slitting travelling webs or sheet-like board material includes a pair of coacting rotary circular knives mounted on each side of the path of the web with the two peripheral cutting edges being in contact with one another. The device includes the use of a flat spring to provide an arrangement for biasing one knife against the other knife in the axial direction to provide the desired elastic pretension therebetween.

Abstract: A knife shaft assembly (1) for a document shredder formed from a series of cutting disks (3) arranged on a shaft (2) with spacer rings (4) disposed between them. The spacer rings (4) are compressible, and a securing mechanism, such as snap rings (6) received in grooves (5), is provided on the shaft to secure the cutting disks (3) on the shaft (2) under compression. During assembly, the spaces between the cutting disks (3) are adjusted to a predetermined size by compression in the axial direction. This arrangement enables material costs to be kept low while assuring high dimensional accuracy of the knife shaft assembly.

Abstract: The invention comprises a machine for slicing food products into then strips. Two stacks of spaced, axially aligned circular blades are positioned so as to be driven in counterrotating intermeshing relationship. Each of the blades comprises a central hub connected to a peripheral cutting ring by a plurality of spokes. Spacers are provided between adjacent ones of the circular blades. The stacked blades are assembled with the spokes of succeeding ones of the blades displaced by a predetermined angular amount, so that the spokes define a plurality of helical paths through the interior of the stacks. As the blades are rotated the food product is sliced by being forced between the spaced blades, and the resulting strips are deposited within the interior of the stack to travel along the helical paths defined by the spokes and be discharged at the end of the stack.

Abstract: This invention pertains to the cutter area of size reduction equipment for plastic or other waste material. The primary objective of the invention is to provide a primary and secondary cutting area within the cutting head assembly so that the granulate is properly sized upon discharge. In the normal passage of the material through the cutter assembly, this reduction to a predetermined size is accomplished in the primary cutting area. However, if material inadvertently passes through the primary area without being properly sized, it will be appropriately dimensioned in the secondary cutting area prior to discharge. The invention pertains to a cutter mechanism which uses a single plane of counter rotating, alternating cutters in conjunction with a stationary cutting surface to achieve the primary and secondary cutting actions. The invention further addresses design considerations of the locating means of both the shaft mounted cutter assemblies and the stationary cutting surfaces.

Abstract: A cutting device for layered or unlayered foil lengths, having good cut quality and an extended period of use before re-grinding of the cutter is required, consists of cylindrically shaped keyway cutter bars with distance rings lying between them, which are mounted on a blade shaft, and of roller blades of right-angles cross-section, which are equally mounted on a blade shaft and wherein each roller blade is pressed by a spring washer against the corresponding keyway cutter bar. The advantage according to the invention consists in that first each roller blade is supported on one of the cutting blades of the keyway cutter bar and that after these cutting shoulders wear off the whole roller blade shaft is turned around and in each case the other cutting shoulder is used for cutting. After these cutting shoulders too have worn off the cutting device is made usuable for further cutting operation by grinding off the cylindrical outer surface of the keyway cutter bars (FIG. 2).

Abstract: A cutter for cutting sheets of material, paper and the like comprises a cup-type main rotary blade and a sub-rotary blade. The main rotary blade is supported by a main rotary shaft and has an edge part for performing cutting. The sub-rotary blade is rotationally responsive to rotational movement of the main rotary blade, has an edge part for performing cutting and is rotatably disposed to face the main rotary blade. A holding mechanism rotatably holds the main and sub-rotary blades so that the respective edge parts face each other in an overlapping manner. The holding mechanism is motor driven to enable the mechanism to move toward or away from the cutting work. A wire and pulley arrangement coupled to the holding mechanism functions to cause the main rotary blade to rotate as the holding mechanism is caused to move. A coil spring or a pair of plate springs bring the edge parts of the main and sub-rotary blades into press contact.

Abstract: An edge trimmer for trimming the side edges of a running length of metal strip having upper and lower rotary shearing cutter discs engaging the top and bottom respectively, of the strip being trimmer includes top and bottom cylindrical strip stabilizers mounted coaxially with the cutter discs engaging the top and bottom surface of the strip adjacent the trim line, and a movable holddown roll disposed inboard of the top strip stabilizer and cooperating with the lower strip stabilizer to stabilize the strip at a location spaced inward from the trim line. The holddown roll is movable between an operable position engaging the strip and an inoperable position permitting access to the cutter disc for servicing.

Abstract: In an apparatus for cutting a metal sheet, a pair of hollow shafts are mounted in a housing for angular movement relative thereto. The hollow shafts have respective hollow bores whose respective axes are eccentric to the axes of the respective hollow shafts. A pair of holder shafts are rotatably fitted respectively in the hollow bores. A pair of circular cutting blades are mounted respectively on projecting forward ends of the respective holder shafts in concentric relation thereto for rotation with the respective hollow shafts. When the holder shafts are rotated to rotate the cutter blades, the cutter blades cooperate with each other to cut a metal sheet caused to pass between the cutter blades. An interlocking unit is arranged between the hollow shafts, for enabling the hollow shafts to be moved angularly about their respective axes in an interlocking fashion, thereby moving the axes of the respective holder shafts toward and away from each other to adjust an amount of lap between the cutting blades.

Abstract: An improvement in cutters used in the field of paper manufacturing consisting in that the support-bearing for the knife is connected to a raising and lowering device through a structure elastically deformable and able to impart elastically opposing movements to the knife. These movements are essentially motions of torsion which allow compound movements thereby providing continuous engagement between the knives and the counter knives during rotation. Said elastic structure consists of at least one rectangularly shaped elongated blade formed of steel.

Abstract: A device for slitting an elastomeric strip into two identical halves of cross-section suitable for use as windshield wiper blades includes a drive roller which grips the strip and draws it through stationary dies past the operative cutting area of a pair of rotary cutters having cutting tip configurations and placement effecting cutting of the strip to provide sharp, consistent corners at the resulting blade tips.

Abstract: Disclosed is an apparatus to longitudinally cut a cord reinforced rubber sheet into at least two strips of tire ply stock while the sheet is being conveyed past the apparatus. The apparatus includes a slitting device that utilizes shear-type action to cut through the sheet by the interaction of rotating disc-like upper and lower slitters. The upper slitter is power driven while the lower slitter is rotated by frictional contact between the upper and lower slitter. The apparatus may include a trimming device for trimming a boundary strip of the sheet. The trimming device also utilizes shear-type action to trim the sheet by rotating disc-like upper and lower trimmers similar to the upper and lower disc-like slitters of the slitting device.

Abstract: The present invention provides a method and apparatus for slitting sheet material. The apparatus includes a first arbor shaft for mounting and rotatably driving a first rotary cutter. The first cutter is comprised of at least one rotary knife element having two opposite side faces, and the first arbor shaft is constructed to allow axially movement of the knife element along the first arbor shaft. A second arbor shaft mounts and rotatably drives a second rotary cutter. The second rotary cutter is comprised of at least one rotary knife element which has two opposite side faces and is movable axially along the second arbor shaft. The second arbor shaft is also selectively movable radially with respect to the first arbor shaft to provide a selected intermeshing overlap region between the first cutter knife element and the second cutter knife element.

Abstract: In a copier with a copy sheet output slitter for slitting the copy sheets outputted by the copier into a selected plural number of smaller sub-sheets cut in the direction of movement of the outputted copy sheets, and wherein the output slitter also optionally provides uncut copy sheet output, and provides a transport path for both cut and uncut copy sheet output, the improvement wherein the output slitter comprises a plurality of first generally cylindrical metal rollers rotatably driven on a first shaft and a second plurality of generally cylindrical metal rollers on a second shaft parallel to and spaced from the first shaft, the spacing and the diameters of these rollers being such that the first rollers interdigitate the second rollers, the first and second rollers having sharpened opposing radial end surfaces selectively forming paper slitting shears therebetween by end-abutting selected ones, or none, of the first and second rollers by selective movement of rollers along the axis of at least one of the s

Abstract: A circular rotary slitter construction comprises a body hub having a circular perimeter and at least one axially facing surface. A cutting edge hoop cylinder is fixedly mounted on the body hub perimeter. At least that portion of the axially facing surface contiguous to the hoop cylinder is axially inset from an annular cutting edge of the hoop cylinder so that the annular cutting edge margin of the hoop cylinder overhangs the contiguous axially facing surface cantilever fashion and the cutting edge is axially outwardly spaced relative to the contiguous axially facing surface. The hoop cylinder is adapted to be made from tool steel and the body hub is adapted to be made from a more easily machined material such as aluminum and at least partially from a suitable plastic material.

Abstract: An attachment for a field chopping machine has a cutting device arranged in a picking region of a working unit and having two cutting disks which rotate in opposite directions and arranged so that at least one of the cutting disks is turnable about an further axle which lies in a working direction of the machine normal to its pivot axle and is held in frictional engagement with the other cutting disk under the action of the spring acting on the further axle.

Abstract: A slitter knife holder has a rod for supporting a slitter knife. Strain gauges are attached to the rod. There is provided a conversion circuit for converting changes in electric resistance of the strain gauges due to the deflection of the rod caused by the pressure of contact of the upper blade with the lower blade of the slitter knife into a signal indicative of the pressure of contact of the upper blade with the lower blade. The signal from the conversion circuit may be applied to a contact pressure monitor for indicating the signal directly to an operator or to an automatic contact-pressure control system.

Abstract: A slitter apparatus for slitting a sheet member such as a corrugated cardboard or the like into predetermined widths. At least one pair of upper and lower rotary cutters and at least one pair of upper and lower shifters corresponding thereto being disposed above and below a conveying passage for the sheet member. The pair of upper and lower shifters being operatively arranged to be moved slidably along on respective guide rods by respective feeding screws. The pair of upper and lower rotary cutters being selectively imparted with a predetermined shift movement. At least one of the upper and lower rotary cutters being rotatably supported on one end portion of a supporting arm, and the other end portion of the supporting arm being in threaded engagement with a screw rod provided in parallel with the guide rods so that the supporting arm may be swingable about the screw rod and also may be movable along the axial direction of the turning screw rod.

Abstract: The invention concerns a document shredding machine of the kind comprising two cutter assemblies, each assembly comprising a drive shaft upon which cutter discs are mounted at spaced intervals, the assemblies being mounted so that the discs of one assembly enter into the gaps between the discs of the other assembly with little or no clearance, the machine comprising a drive mechanism to rotate the drive shafts in opposite directions, so that the overlapping discs collectively act to cut material fed into the nip of the machine into narrow strips. One of the cutter assemblies is capable of movement away from its normal working position, whereby when thick documentary material is fed into the nip, as would otherwise tend to jam the machine, the cutter discs may be permitted to separate somewhat allowing the documentary material to pass through the machine without jamming.

Abstract: A shredder includes a pair of blade assemblies operated at high speeds to receive and shred paper material, such as notes or coupons. The blades of the assemblies are disposed to contact and overlap each other. Means are provided to control the amount of overlap and loading of the blades.

Abstract: Apparatus for slitting sheet material includes a pair of rotatable shafts having cooperating cutting knife assemblies thereon. The knives on one shaft are in the form of axially-spaced knife rings receivable between knife members on the other shaft. The knife rings are elastically deformable axially of the shafts and are spaced-apart a distance slightly greater than the spacing between the knife members to insure the absence of any gaps between the cooperating cutting knives. The knife members are releasably clamped axially on their shaft and are biased apart upon release of the axial clamping force in order to allow positioning of the knife rings between the knife members. Central mounting holes in the knife members increase in size from the axial center thereof toward the opposite ends thereof for allowing limited tilting movement of the knife members relative to the shaft on which they are mounted.

Abstract: In a cutting device of the shearing type comprising two circular blades one of which is in the form of an elastic disc displaceable on a bracket by pressure from a pressure element engaged by a lever, the cutting edge of said blade in the form of an elastic disc being disposed against the cutting edge of the other blade, the improvement wherein said bracket is disposed within a bearing sleeve which in turn is disposed within a bearing of said disc, said bearing sleeve being connected to said lever in an axially inflexible manner, said pressure element disposed adjacent to the cutting area of said blade in the form of an elastic disc and passing a moment into said bearing sleeve and said bearing which is opposed to the moment of any reaction force imposed on said disc in its cutting area.

Abstract: A high-speed rotary shear for making, in the direction of travel, straight cuts, curved cuts, and combinations thereof, through a continuously moving web of thin, pliable, compliant, cut-resistant material and a process of making such cuts. The shear comprises at least one pair of first and second cooperating blades located to either side of the web. Each of the first and second blades is mounted on a blade support affixed to a rotatable shaft. At least one of the first and second blades is in part at least elastically mounted on its support and is itself flexible. The axes of the shafts of said first and second blades lie in spaced horizontal planes and in vertical planes which intersect at an angle such that the first and second blades will be skewed with respect to each other at an angle of from about 1.degree. to about 6.degree. and such that the first and second blades, having the same outside diameter, will have a single point contact, cutting the web with a scissors action.

Abstract: An arrangement for dampening vibrations in and lubricating the operative edges of a pair of cooperating sheet cutting discs. A block member having a surface comprised of a solid lubricant is yieldably biased so that said surface engages the face of one of the discs that is in operative engagement with a face of the other disc.

Abstract: An air bearing slitter wherein the slitter disc is mounted on a hub that is freely rotatable and axially movable relative to a shaft on an air bearing. This arrangement has been found to improve the slitter knife life between sharpenings and to permit the use of tungsten carbide coated slitters for slitting paper.

Abstract: A cutting tool consists of circular, rotatably mounted upper and lower blades, the upper blade extending past the periphery of the cutting shoulder of the lower blade and bearing resiliently against it. The thickness of the cutting shoulder of the lower blade is less than the distance of the said extending of the upper blade, and the material hardness of the upper blade is greater than that of the lower blade.

Abstract: Slitting apparatus for trimming the edges of a web of corrugated board and longitudinally cutting the web into a plurality of narrow webs is constructed with selectively operable fluid operated means that clamps the working heads in adjusted positions along the length of their respective drive shafts. The fluid operated means includes a plurality of pressure bars extending parallel to the length of each shaft and disposed within different grooves thereof. The pressure bars are constructed of spring steel, and each is operatively positioned to clamp a plurality of heads in operating positions by engaging keys secured to these heads. The keys extend beyond the faces of the heads, and for each of the heads include notches that provide clearance for the extending portions of the keys secured to adjacent heads.The drive shafts are parallel to each other.