Background to the invention Although the present invention will be described with particular reference to a rotary hand piece for shearing sheep, in which the rotary hand piece has a cutting assembly comprising a rotating cutting blade, it is to be noted that the scope of the present invention is not limited to the described arrangement or embodiment, but rather the scope of the present invention is more extensive so as to include other forms of the rotary blade or hand piece, other assemblies of the various components forming the hand piece and how such components are assembled, and other uses of the hand piece than those specifically described.

Further, it is to be noted that although the invention will be described with particular reference to a hand held hand piece, the scope of the present invention is more extensive, so as to include other forms of the hand piece having the same or similar cutting assembly which arc not used as hand pieces, but rather are used as part of a larger cutting assembly, such as for example, a robotically controlled cutting head having different forms of the cutting assembly, cutting heads and cutting assemblies located at

the end of a mechanical arm or similar, cutting assemblies provided with automatic shearing machines or the like.

Rotary hand pieces were developed to overcome many, of the disadvantages and shortcomings of conventional reciprocating hand pieces in which a fixed comb and movable cutter are held together in intimate contact. However, whilst the rotary hand pieces are generally effective in most situations, there are some circumstances in which the rotary hand piece suffered from one or more problems, such as for example, being able to effectively cut very fine wool of the type produced by fine wool Merino sheep. As the wool of fine wool Merino sheep is extremely fine, there is a tendency for the wool to wrap around the rotating parts of the hand piece, particularly the blade or a hub or shaft connecting the blade to the drive mechanism when shearing Merino sheep and similar fine-wooled animals. Therefore, there is a need to provide a modified or improved form of the rotary hand piece which addresses the problem of stray fibres becoming entangled or wrapping around the rotating components adjacent the blade.

A further problem associated with some breed of sheep, most notably fine wool Merino sheep, is that the fleece of such animals is extremely thick, so that it is difficult in some circumstances to push or otherwise force the hand piece through the mass of fibres forming the fleece to effect a clean cut of the fibres, particularly without the fibres becoming entangled around the rotating components adjacent the blade.

Various different forms of drag are experienced during shearing operations which provide resistance to the hand piece moving through the fleece and making the shearing operation more labour intensive or slow down the pace of the shearing operation. One form of drag is that experienced on the body of the hand piece caused by the cut fleece pressing against the body of the hand piece or cutting head. It is desirable if the cut fleece can be lifted free of the hand piece, preferably through a vibratory or other motion of the handpiece or cutting head but which in turn does not place an unacceptably uncomfortable vibratory effect for the person doing the shearing.

Thus, there is a need for a modified or improved hand piece which is easier to push through the fleece of some animals, particularly fine wool Merios.

Therefore, it is an aim of one form of the present invention to provide a hand piece which is easier to use when cutting fine wool Merinos or similar animals having a densely-packed fleece or similar of fine to very fine fibres, whereby the chances of the fibres becoming entangled within the hand piece are reduced or eliminated.

Summary of the Invention According to one aspect of the present invention, there is provided a generally circular blade for use in a rotary cutting head, said blade having a central portion and a perimeter portion, wherein the perimeter portion is angularly inclined to the central portion, the blade having a cutting edge on the peripheral edge thereof.

Preferably the cutting edge is defined by a plurality of cutting teeth spaced apart around the perimeter of the blade. The teeth may be generally radially orientated, or may be curved.

Preferably the central portion is provided with an aperture. The blade may be connected to the drive mechanism by a spindle, axle, shaft or similar being received through the centrally located aperture.

The blade may be connected to the cutting head by a tensioning means, preferably a manually adjustable tensioning means.

Optionally the cutting head is provided with adjustable tension for adjustably tensioning the blade to the hand piece. Typically, the adjustable tension is obtained by a threaded bolt arrangement in combination with removable shims so that one part of the bolt arrangement is received within another part of the arrangement. In another embodiment, the adjustment tension is provided by a resilient gasket or washer located between the rotary blade and the hand piece.

The blade may include an upstanding deflector collar at or adjacent the interface between the central portion and the inclined portion. The deflector collar preferably includes a radially outer surface of non-planar configuration. Said non-planar configuration may comprise a series of ribs or corrugations. Said radially outer surface may be inclined to the rotational axis of the blade at an angle of between 5° and 45°, preferably between about 206 and 306 to the rotational axis of the blade.

The inclined portion may be integral with the central portion and the deflector collar may be integral with the central portion.

In use, the deflector collar lifts and vibrates fibres over the body of the cutting head, thereby preventing the fibres from becoming trapped between the rotating blade and the stationary cutting head. Also, a portion of the cutting head preferably nests within the annular space defined radially inwardly of the collar, thereby creating a labyrinth path for fibres, and preventing fibres entering the space between the upper surface of the central portion and the under surface of the cutting head.

According to another aspect of the present invention, there is provided a cutting head including a drive mechanism for driving a generally circular disc shaped rotary blade having a substantially planar central portion and a perimeter portion, wherein the perimeter portion is inclined relative to the central portion, the peripheral edge of the perimeter portion having a cutting edge thereon. The cutting head preferably includes a plurality of cutting bits mounted to the cutting head in close proximity to the cutting edge, the cutting edge being adapted to interact with the cutting bits to cut through material in use.

Typically, the cutting bits are of generally elongate configuration, and define a cutting surface thereon adapted to engage with the cutting edge on the blade. The cutting bits may be comprised of high tensile metal and are preferably generally radially aligned, and project in a forward direction of the cutting head. The cutting head preferably has a series of comb teeth projecting forwardly in a plane perpendicular to the axis of rotation of the blade, each comb tooth having a cutting bit associated therewith, the teeth being spaced apart to define a series of fibre receiving channels, and fibres entering said channels being adapted to be cut by the rotating blade and the cutting bit adjacent to the channel. The cutting bits are preferably able to reciprocate backwards and forwards between a relatively more forward position and a relatively more rearward position, and are held under tension in said forward position. The tension may be provided by a tensioning means located at or towards the rear end of the cutting bits. The cutting bits may be adapted to pivot about a pivot axis which is perpendicular to the length of the cutting bits.

The cutting bits are preferably mounted within a cartridge which retains the individual cutting bits in their operative orientation, and allows for quick replacement of all cutting bits simultaneously. The cartridge is preferably comprised of a thermally conductive material to allow heat in the cutting bits to dissipate through the cartridge.

Typically, the cutting bit tensioning means is a ring or part ring of a resilient material, typically a rubber or rubber-like material, such as for example, neoprene.

Optionally the neoprene part ring has an L-shaped profile or similar in cross-section.

More typically, the rear of each individual cutting bit is located against the L-shaped profile such that the lower surface of the end of the cutting bit rests against the junction of the two arms of the"L". Even more typically, the rear end of the cutting bits is located in the rebate of the Lshaped profile of the ring so as to hold the cutting bit and to bias the cutting bit towards the more forward position.

Optionally the hand piece is provided with a vibration means for vibrating the hand piece. The vibration means may be a mechanical vibration means, such as for example, a rotatable eccentric collar or similar, an electrical vibration means, such as for example, a miniature motor, or a pneumatically operated vibration means, such as for example, air operated valves or rotating shafts.

In one embodiment, the mechanical vibration means is an out of balance eccentric weight located on a rotating shaft, i. e., an eccentric collar, power drive or similar which causes vibration as a result of rotation. In another embodiment, the electrically operated vibration means is an oscillating solenoid or a micro motor, such as for example, of the type used in the vibration mode of a mobile phone, in which an asymmetrical weight or shaft is rotated by a miniature motor. Alternatively, in another embodiment, the vibrating means is a pneumatically operated, oscillating or reciprocating weight, shaft or similar.

Yet another vibration means is hydraulically operated.

Brief description of the drawings The present invention will now be described by way of examplc with reference to the accompanying drawings, in which :

Figure 1 is a vertical cross section of one form of the forward facing end of the hand piece of the present invention showing the improved form of the blade and provided with one form of the vibrating means; Figure 2 is a top plan view of the hand piece of Figure 1; Figure 3 is a side elevation view of the hand piece of Figure 2 showing the teeth located around the inclined edge of the blade; Figure 4 is a vertical cross-section of one form of the hand piece of the present invention having an inclined blade provided with a fibre deflector collar and not provided with a vibration means; Figure 5 is a side view of one form of the inclined blade; Figure 6 is a cross-sectional view of the blade of Figure 5 ; Figure 7 is an enlarged view of one part of the peripheral portion of one form of the inclined blade; Figure 8 is a plan view showing one form of the teeth of the rotary blade and one form of the cutting bits and showing the angle of inclination between the teeth and the cutting bits; Figure 9 shows a side view of a rotary blade which includes a deflector collar ; and Figure 10 shows the blade of Figure 9 in cross-section.

Detailed description of preferred embodiments Figures 1 to 3 show one form of a rotary hand piece, generally denoted as 2, comprising a rear portion which acts as a handle 4 so that the hand piece can be held in the hand of a user, such as for example, a shearer. Alternatively, handle 4 may be adapted for fitting to an arm of an automated shearing machine or similar. The rearmost part of handle 4 is fitted with an adapter to allow it to be connected to a convenient drive means so that the hand piece can be driven by the drive means, such as for example, a driving shaft 5 connected to a driving means such as an electric motor, an air motor, a hydraulic motor or similar. Altematively, the rear of handle 4 is adapted to be driven by a suitable driving means of an automatic shearing apparatus, robotic arm or similar. It is to be noted

that any suitable driving means can be used, such as an electric motor, an air motor, hydraulic motor or other driving means as required by the circumstances.

The forward portion of hand piece 2 comprises a main body portion 6, and a base in the form of a substantially planar comb 8 having multiple forwardly-directed fingers or teeth 10 extending in the common plane of the comb. The main body portion 6 houses a cutting assembly 12 comprising a number of components which cooperate together to transmit motion from the drive shaft 5 to rotating blade 16, such as for example, bearings, meshed gears, spindles and the like. The cutting assembly 12 is located in a cavity 14 positioned on the underside of the body 6. It is to be noted that the use of terms describing the orientation of the rotary hand piece and its components, such as rear, forward, underside and the like, refer to the rotary hand piece when in its normal in-use position, as shown in Figure 1, in which the forward facing direction corresponds to the position of the fingers 10. This orientation and the description is not meant to be limiting of the scope of the present invention but is used for ease of description and understanding. The rear handle portion 4 and body portion 6 of the rotary hand piece enclose a suitable drive mechanism which is connected to the cutting assembly 12 to drive a rotary blade 16, such as shaft 18 and bearing arrangement 20.

An eccentrically weighed collar 19 is located around shaft 18 in Figure 1 so as to rotate in accordance with corresponding rotation of shaft 18. As collar 19 is an offset weight as it rotates, vibrations of shaft 18 are produced which are transmitted to the hand piece and particularly the fingers 10 of comb 8 attached to the base of the hand piece. A blade retaining plate 21 connects rotary blade 16 to the hand piece in a location between the comb 8 and the bearing arrangement 20.

One form of the rotary blade 16 will now be described This form is provided with a substantially planar central body portion 24 and an inclined peripheral portion 26. A suitably threaded spindle arrangement 28 is received in a centrally located aperture of the central body portion 24 of blade 16. The blade is thus generally dish or convex shaped, and defines a. cutting surface on the underside thereof, adapted to engage with a series of cutting bits, as will be described in more detail below.

The forward facing body 6 of the rotary hand piece 2 is in the form of a generally tounded front and is provided with a guide means in the form of a plurality of forwardly- directed teeth or fingers 10 arranged in substantially parallel spaced apart relationship to each other, around and about the front of the hand piece extending from one side of the hand piece to the other side in an arcuate arrangement, as shown more particularly in Figure 2. The fingers are arranged to point generally in alignment with each other in substantially the same direction which direction corresponds to the forward direction of movement of the hand piece when in normal use. It is to be noted that the fingers can be arranged radially at the front of the hand piece or substantially parallel to each other. It is also to be noted that the underside of the fingers 10 form the lower part of the hand piece 2 at and towards the front of the hand piece and the comb 8 forms the remainder of the undemeath of the hand piece extending from towards the front to the rear as shown in Figure 1 and fingers 10 and comb 8 are the part of the hand piece which contacts and rets upon the skin or body of the animal when being shom.

The Angers may be substantially identical to each other or may be different from one another. A fleece receiving channel 9 is defined between adjacent fingers 10, and as the hand piece is pushed in a forward direction into the fleece of a sheep or other animal, the individual fibres enter into the fleece receiving channel and will be sliced by the blade as it passes towards the rear most end of those channels 9. The manner in which the fleece is cut is described in more detail below.

Typically, the fingers include a"sighter"finger 11 and a"guide"finger 13, located at either end of comb 8. The"sighter''and"guide"fingers are used to assist and guide the hand piece through the fleece on the pathway required by the shearer. Further, it is to be noted that the fingers can have any suitable shape, size, profile or cross-section as required. Also, the number of fingers can vary from about 8 up to about 20, with 9, 10, 11, 12, 13 being typical numbers of fingers.

The forward distal ends of the fingers are provided with a rounded tip portion 30 which enters the fleece of the sheep being shown using the hand piece. A longitudinal recess 32 is located in the upper surface in use of each of the fingers 10 and extends along the lengthwise extending axis of the fingers. A movable cutting bit is located in each

recess in such a way so as to undergo reciprocating movement in an alternately forwards and backwards direction in alignment with the fingers. Cutting bits 34 may be individual cutting bits, or may be a cartridge of cutting bits. The cartridge is preferably formed of a heat conducting material such as steel, copper, brass or other alloy, which will properly retain the cutting bits in position, allow the reciprocal movement of the cutting bits, but which will allow heat generated in the cutting bits to dissipate as the blade rotates. As cutting bits 34 are subject to wear, the cutting bits, in whatever form, are replaceable either individually or as a complete cartridge. In one form, the cutting bits are substantially C-shaped. However, other shapes, sizes, profiles, cross-sections of the cutting bits are possible, including flat cutting bits. A tcnsioning means in the from of a part circular rubber tube 36, such as for example, a length of circular tube, made from neoprene or similar, is located at the rear of the cutting bits to provide a forward bias for the cutting bits so that in the at-rest position, the cutting bits adopt a relatively more forward position within slot 32 provided in the upper surface of each finger 10, as shown in Figure 1.

In one form, the cutting bits 34 can take a grooved profile, such as for example, a V-shaped or C-shaped cross sectional profile with the groove located between the sides of the cutting bits. More particularly, the forward facing end of the grooved cutting bit is tapered. The sides of the cutting bit 34 cooperate with the rotating blade 16 to cut material located between teeth 40 provided around the periphery of the blade and the edges of the cutting bit.

The cutting bits 34 are located such that the forwardly-directed edge or tapered surface of each cutting bit is located adjacent the cutting surface or surfaces of teeth 40 provided at regularly spaced apart locations around the edge of the peripheral portion of rotary blade 16, so that as blade 16 rotates, the teeth 40 engage with the cutting surfaces of the cutting bits at or towards the forwardly-directed end of the cutting bit to push the cutting bit rearwardly and slide along the front surface, thereby severing material located between the rotating blade and the cutting bit In one form, the blade is a dished or domed shaped blade having an inclined peripheral portion with a cutting edge on the periphery thereof, generally defined by a

series of cutting teeth which interact with the cutting bits to slice through the fibres to be cut. The cutting bits generally engage and press against the cutting blade so that there is constant but reasonably light contact between the blade and the cutting bits. The teeth on the blade tends to force the fibres into the nip between the blade and the cutting bit, and as the blade rotates past the cutting bit the fibres are sliced at the interface in a clean and efficient slicing motion.

One form of the dished or domed blade of the present invention will now be described with particular reference to Figures 5 to 7.

In Figures 5 to 7, the rotary blade 16 is provided with a centrally located aperture 42 and a substantially planar body portion 24 located surrounding central aperture 42. A perimeter portion 26 is located radially outwardly of and surrounding the planar central portion 24. Perimeter portion 26 is located out of the plane of the planar body portion 24 in the form of a flange or peripheral extension, so as to form a cup-like or domed shape.

The downwardly inclined perimeter 26 is provided with a number of regularly spaced apart teeth 40 located around the entire circumference of the perimeter portion 26. The angle of inclination of the respective teeth 40 is the same as the angle of inclination of the perimeter portion 24, such that the teeth 40 are all angularly inclined to the planar body portion 24.

In one form, the teeth are substantially arcuate, having curved leading and trailing edges, as shown in Figures 5 and 7, whereas in other forms, the teeth are substantially triangular in shape and profile, having straight edges which meet at an apex in which the apeces are located along the extreme distal part of the perimeter as shown in Figure 8.

It is to be noted that the exact shape, profile, size and arrangement of the teeth 40 can vary to suit cutting requirements depending upon the use of the hand piece.

Additionally, the exact size, shape, profile and arrangement of the blade 16 can vary.

Additionally, other forms of the blade can be provided with combinations of different teeth, such that there are two or more different styles of teeth on the blade.

In some embodiments, the leading edge of each tooth is provided with a sharp cutting surface, whereas the trailing edge of each tooth is not necessarily a cutting edge.

In one embodiment, as shown in Figure 7, the perimeter portion 26 and teeth 40 are tapered in the direction from the central portion 24 of the blade towards the tip 44 of the teeth 40 at the perimeter of the blade 16. Even more typically, the edge or tip 44 of the teeth 40 is tapered or bevelled. Typically, the angle of inclination of the tooth or perimeter portion to the planar portion of the blade is about 28°, whereas the bevel at the tip of the tooth is about 30°, as shown more particularly in Figure 7. However, any convenient taper, bevel or angle of inclination is possible depending upon the use of the blade.

It is to be noted that the extreme end or tip 44 of each tooth 40 is provided with a sharp edge or profile to assist in more effective cutting of material located between the blade and the cutting bit In another form of the hand piece of the present invention such as is illustrated in Figure 4, the rotating blade is provided with an upstanding collar on the convex side of the blade, the collar arrangement acting as a deflector preventing or reducing the incidence of fibres being located in the gap between the upper side of the rotating blade and the underside of the body of the hand piece. In particular the deflector collar prevents fibres from being wrapped around the moving or rotating components of the hand piece.

In one form, the deflector collar is in the form of an upstanding flange 50 or cowing, faring or similar arrangement having a front surface 52 which is substantially concave in shape, leading to and transiting into the forward curved portion of the curved body 6 forming the front of the body of the hand piece. The front of surface 52 of deflector 50 may be straight, such as for example, inclined at any suitable angle from 06 to 45D, or more to the plan of the blade. Typically, the angle of the deflector is from 5'to 30*, preferably from 10° to 20°. The rear face 54 of the upstanding flange 52 is essentially straight and can be inclined to be substantially vertical. If the flange is inclined, it is typically inclined back towards the body of the hand piece so as to reduce the gap between the top of the flange 50 and the front of the body. The flange is located so as to extend on the opposite side of the blade to the inclined peripheral portion 26. It is to be noted that the deflector can be any suitable shape, size, profile and arrangement depending on the use of the blade.

It is considered important that the inclined face or front surface 52 of the deflector collar 50 is non planar, that is it may be of fluted, cormgated, or otherwise irregular configuration. This irregular surface will have the effect of"bouncing"or otherwise lifting the cut fleece up and away from the hand piece. The irregular surface will thus decrease the drag experienced on the hand piece as it is pushed through the fleece in a typical cutting stroke.

With particular reference to Figure 8, one form of the cutting bits and of the rotary blade and the relationship between the two is illustrated and now described. Cutting bits 34 are all arranged to extend radially outwardly from the front portion of the hand piece, typically in alignment with fingers 10 (as shown in Figure 8). Teeth 40 of the blade 16 all extend radially outward from blade 16 and are all substantially triangular, having a rounded distal apex. As teeth 40 rotate past cutting bits 34, any material located there between is cut. The angle between the cutting surface of one cutting bit 34 and the cutting surface edge of corresponding tooth 40 is illustrated in Figure 8 and is shown to be about 30° to the horizontal. That is the cutting edge on the cutting bits and the cutting edge on the under surface of the blade are both inclined at the same angle so that an intimate face to face contact of the two cutting surfaces is achieved. However, any angle from about 0° to 50"is possible with preferred angles being between 10° and 4011, more preferred from 20"to 35°, with about 30-being the most preferred.

It is to be noted that since the angle of inclination of the peripheral portion of the blade with respect to the central portion is substantially the same as the taper or bevel on the forward edge of the cutting bit, there is a minimum clearance between the inclined, peripheral portion of the blade or tooth and the-cutting bit for cut fibres to become entangled in the rotating parts of the hand piece. Further, owing to the presence of the deflector collar, cut fibres ride up the forward facing surface of the deflector away from the cutting bits or the gap between the rotating blade and the hand piece so that there is. less chance of the fibres becoming entangled around the rotating parts of the hand piece or within the body of the hand piece.

Figures 9 and 10 show the blade including the deflector collar 50 in more detail.

As shown the deflector collar 52 is located on the convex side of the blade. The front face

52 of the collar is inclined as shown so as to form a ramp-like surface to induce the cut fleece to move up and over the hand piece during a normal shearing stroke.

The front face is preferably not smooth, that is, it preferably has some form of non-planar formation formed thereon which as the blade 16 rotates will have the effect of vibrating or loosening the cut fleece, providing further decrease in the drag of the fleece over the top of the hand piece. The non-planar configuration shown in the drawings preferably comprises a series of vertically aligned corrugations 55 which extend around the periphery of the collar. As the cut fleece is contacted by the corrugations there will be a tendency for the fleece to move away from the rotating collar and, it is believed, significantly reducing the drag between fleece and hand piece.

Other forms of irregular formations on the collar are possible, including, for example, fluting, ribs, button-like protrusions, and the like.

The collar may be made separate from the blade, and fixed to the blade using suitable fastening rivets or the like, or the blade and collar may be integrally formed. The front face of the collar may be inclined at a relatively steep angle to the horizontal, say 45 degrees or more. The collar thus serves two main purposes. Firstly it prevents fibres passing into the gap 57 between the upper surface of the blade and the undersurface of the hand piece. Secondly it serves to deflect cut fleece upwardly, helping to reduce drag as the hand piece is used to execute a shearing stroke.

The described arrangement has been advanced by explanation and many modifications may be made without departing from the spirit and scope of the invention which includes every novel feature and novel combination of features herein disclosed.

Those skilled in the art will appreciate that the invention described is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident