GB2378378A

GB2378378A - Rotary cutter with protruding blade, having serrated and smooth sections

Info

Publication number: GB2378378A
Application number: GB0119219A
Authority: GB
Inventors: Richard John Hawes
Original assignee: AEW Engineering Co Ltd
Current assignee: AEW Engineering Co Ltd
Priority date: 2001-08-07
Filing date: 2001-08-07
Publication date: 2003-02-12
Anticipated expiration: 2021-08-07
Also published as: GB2378378B; GB0119219D0

Abstract

The rotating severing tool has a radially protruding blade 16 over part of its surface. The blade has cutting knife and sawing segments (figure 2, 18, 20, 24, 26). The tool is mounted on an axis that is perpendicular to the feed direction and the blade passes through a severing position in a plane perpendicular to the direction in which material is fed into the apparatus. The blades 16 are mounted on a circular plate, and the radius of the blades increases radially form the non-cutting area, over the saw toothed and slicing zones. Control means synchronise rotation of the tool and advance of the material 10. Preferably visual or ultrasound signals will also divert the material, change the direction of rotation and move the axis 28 about which the tool rotates. Adjustable conveyors 58, 60, 62, 68, 70, 74, a means, e.g., pendulum or conveyor belts 78 to hold the material, rollers 88, 90 for supporting the blades 16 and jets for cleaning 84 the blades are disclosed. The method, apparatus and severing tool are separately claimed. The apparatus is used for dividing meat products containing bone 64, e.g., a loin of pork 10.

Description

Title: Apparatus and methods for severing material containing soft and brittle components Field of the Invention This invention concerns apparatus and methods for severing material containing soft and brittle components (material of the type described) and is especially of use in cutting meat on the bone.

Background to the invention When cutting meat products such as pork loin (to give loin chops), rib of beef (to yield Tbone steaks) and leg of lamb (to give lamb chops), a number of problems have been experienced affecting the quality and safety of the cut product.

One such problem is smear of blood and fat across the cut face, so that the resulting product does not look as nice as it should, when displayed for purchase.

A second problem which can arise is bone chipping, so that the cut product can include tiny pieces of bone. This is not only unpleasant when eaten but is potentially dangerous.

In an attempt to reduce the risk of bone chips in the cut product, the cutting of meat on the bone has tended to be performed using a band saw. However whilst this does reduce the risk of bone chippings being present in the cut product, band saws do produce smear and inherently produce a large volume of waste and debris, known in the trade as sawdust.

Additionally band saws tend to require hand loading of product to be cut, which restricts the throughput speed of such machines, and are time consuming to adjust for different portion thicknesses where the requirement is to cut to constant weight.

It is an object of the present invention to provide an improved method and apparatus for severing material such as meat on the bone, which does not suffer from the above disadvantages and can be operated in a continuous manner (i. e. with automatic feeding of product for cutting in a continuous or pseudo-continuous manner), and in which the product to be cut can be indexed in a controlled manner between cuts, so that the thickness of the cut portions can be varied during a cutting programme, so as to accommodate varying product cross-section, and yield portions of substantially uniform weight.

Summary of the invention According to one aspect of the present invention apparatus for severing material of the type described comprises : (1) a delivery mechanism for delivering material to a cutting position; (2) an opening through which the material has to pass just upstream of the cutting position, which serves to control the depth of material in the cutting position; (3) a rotatable tool which includes a blade which extends partially around the tool and extends radially beyond a central circular region thereof, the tool being mounted for rotation in a plane generally perpendicular to the direction in which material is fed thereto, so that material downstream of the plane of the blade will be severed from that upstream of the plane of the blade, as the tool rotates through the cutting position; (4) a drive for rotating the tool; (5) a control system for synchronising the delivery mechanism and the tool drive; wherein :- (6) the diameter of the central region of the tool is such that no contact occurs between the material and the central region of the tool, so that after the blade has been rotated through and beyond the material and before it re-enters the material to resume cutting material upstream of the plane of the blade can be advanced into the cutting position, ready for the next cut to be made; and (7) part of the blade comprises a cutting segment and the remainder comprises a sawing segment.

The invention therefore comprises a method of severing material of the type described comprising the steps of :- (1) delivering material to a severing position; (2) controlling the thickness of the material just upstream of the severing position so that the depth of material to be cut is prevented from exceeding a predetermined maximum dimension; (3) rotating a severing tool, part of the circumference of which includes a radially protruding blade part of which comprises a cutting segment and the remainder of which comprises a sawing segment, so that the blade passes through the severing position in a plane generally perpendicular to the direction in which material is fed thereto, so as to sever material on the downstream side of the blade trajectory from material upstream thereof ; and (4) controlling the advance of material into the severing position in synchronism with rotation of the tool, so that material is only advanced after the blade has exited and before it re-enters the material.

The invention is of particular value where the material has a predictable cross section pattern, and can be arranged in the cutting position so that the brittle material will be cut before the soft material (or vice versa). The tool may be mounted so that the appropriate part of the blade enters and cuts through the cross section ahead of the other part, so that brittle material will be cut by the sawing segment, and in general, non-brittle (soft) material will be cut by the cutting segment, of the blade.

Where the material has a predictable cross section pattern it is of course important that it can be positioned so that the regions containing the brittle and non-brittle will be severed in succession one before the other.

The material may be arranged so that the brittle material region will be the first to be severed and the non-brittle material region will comprise the second part to be severed. In this way the sawing segment will form the first part of the blade, and where the depth of

the brittle material can vary (as will normally be the case) the depth to which the sawing segment extends is adjusted, so as to ensure that brittle material will be cut with the sawing segment, and the cutting segment is never employed to cut brittle material, even if some of the non-brittle material is cut by the sawing segment.

According to another preferred feature of the invention a viewing device such as a camera may be positioned to view the end face of each separate log of material before it reaches the severing position, and signals therefrom processed to generate information indicative of the depth of the brittle material and a stop or divert signal may be generated to inhibit advance of that log to the severing position if information relating to the position and/or depth of the brittle material therein indicates the position or depth is incompatible with the depth to which the sawing part of the blade will penetrate, or the depth value is simply greater than a maximum permitted value.

Alternatively an ultrasound transmitter and receiver may be located upstream of the severing position, and signals obtained from the receiver processed to generate information indicative of the depth and position of the brittle material and a stop or divert signal may be generated to inhibit advance of that log to the cutting position if the ultrasound derived information indicates a position or depth of the brittle material which is incompatible with the depth to which the sawing segment of the blade will penetrate into the material cross section, or the depth value is simply greater than a maximum permitted value.

A divert signal may simply cause the delivery mechanism to divert that log to an inspection station, and allow the next log to take its place.

A preferred tool comprises a generally circular plate adapted to be mounted on a shaft for rotation about a notional centre, in which over a first sector the circumference increases radially with angular position, from a starting datum, and a plurality of saw teeth are formed in its periphery, and in a second sector, which follows the first sector in the direction of rotation, the circumference also continues to increase radially with angular position from the starting datum, and a cutting or slicing profile is formed in its periphery,

and over the remaining, third part of the circumference of the plate between the end of the second part and the starting datum, the plate is of substantially constant radius which is less than the smallest radius of the first part.

A radial step typically exists in the tool profile between the end of the second part and the beginning of the third part.

Typically a similar but smaller radial step exists in the tool profile between the end of the third part and the beginning of the first part and dictated by the difference in radius between the first and third parts.

The tool may be machined from a metal plate, but is more efficiently constructed in two parts, comprising a hub portion and an arcuate blade portion secured to the hub to radially extend therefrom around part of its circumference, and the region of the hub portion around which the arcuate blade does not extend, comprises the said third part of the tool.

Typically the hub is in two parts and the inner peripheral edge of the arcuate blade is sandwiched therebetween, and secured by pins, bolts, nuts, rivets or by welding.

In order to simplify blade replacement, or changing the blade, a quick release mechanism may be provided so that either the assembly of hub and blade as a whole, can be demounted, and a fresh assembly located in place, or so that the blade can be removed from the hub, and be replaced by a new blade, leaving the hub in position.

Manufacture of the blade may be from a single arcuate sheet of metal, or more preferably from two shorter arcuate segments welded end to end, with the weld surfaces dressed back to remove the weld line, to form a smooth surface on each side of the blade.

The blade, or each segment of the blade and any teeth or cutting elements along its edge, may be cut from strip or sheet steel using a laser cutting tool.

However constructed, preferably the blade is coated or impregnated with low friction material.

The blade is preferably formed from high-density stainless steel typically Sandvik 7C27M02 stainless steel strip, and with support (see below) a blade thickness of as low as 0. 6mm has been achieved.

Preferably the blade thickness is as small as is compatible with the strength requirements imposed thereon. This is especially important where it is desired to cut down the volume of debris created by the sawing part of the blade.

The thickness of the blade may be reduced if it is supported at least in the region of the point of entry into (and possibly also exit from) the material to be cut.

A preferred support comprises a pair of elements forming a nip between which the blade passes as it rotates into (and/or out of) contact with the material.

The nip preferably exerts only a slight resilient grip on the blade so that friction and drag is minimised.

The elements forming the nip may comprise two rollers adapted to rotate about two spaced apart axes and which are lightly resiliently urged together to reduce the spacing therebetween, and which extend in a radial sense relative to the axis around which the blade rotates.

If cylindrical rollers are employed, there will be relative motion between the roller surfaces and the blade surfaces due to the speed of the blade relative to its surroundings increasing with distance from the axis of its rotation.

In a preferred arrangement the rollers are frusto conical, and the two axes are mutually inclined to bring the two frusto conical surfaces in contact with opposite faces of the blade, the angle of the cone being chosen so that there is no relative motion between the surface of the blade and the rollers The support elements may extend radially between the circumference of the hub and beyond the outermost radius of the blade. However, if the support elements only extend beyond the hub by a radial distance which is less than the smallest radius of the blade, any toothed peripheral region of the blade will always lie radially beyond the ends of the support elements, so that the teeth will not wear down the elements as could otherwise occur.

The radial position of the support elements relative to the axis of rotation of the tool may be adjustable.

In order to give maximum support to the blade the support elements may be mounted for movement inwardly and outwardly in a radial sense, under the control of a drive, which synchronously radially moves the support elements in and out so as to grip a region of the blade which is always close to its sawing or cutting edge. Thus the drive moves the support elements outwardly to follow the radially increasing sawing and cutting edge, and then after the end of the blade has passed, it moves the support elements radially back to be in the correct position to receive the beginning of the blade once again.

The support elements may be formed from a food-grade plastics material or from stainless steel.

A blade support may be provided just ahead of the point of blade entry into the material.

Preferably a blade cleaning station is located to remove debris from the blade after it has exited from the material and before it re-enters the material to make the next cut.

The blade cleaning station may comprise an air jet, or water jet, or brush, or any combination thereof, and is preferably located clear of the material at a position around the blade trajectory so that there is no tendency for debris removed thereby to find its way back onto the material waiting to be cut, or onto cut pieces downstream of the cutting position.

In general debris will be retained between any teeth around the blade, and the cleaning station is adapted to remove material lodged between the teeth in a direction generally perpendicular to the plane of the blade.

Preferably a collecting device, typically including suction, is provided, to collect debris that has been removed from the blade.

The axis about which the tool rotates may be adjustable so as to increase or decrease the distance between it and a surface of the delivery device on which the material to be cut rests.

Additionally the tool axis of rotation may be adjustable laterally relative to the surface on which the material rests when protruding into the severing position.

The adjustment may be manually controllable to enable the apparatus to be set up for a particular type of material, or may be actively controlled during cutting, under the control of an operator viewing the material being cut, or by control signals from a control system supplied with signals from a vision system (camera or scanner) set to inspect the face of severed material (or material to be severed), or from an ultrasonic system set to determine depth and/or position and/or size of brittle material in material waiting to be severed.

Preferably the delivery mechanism does not extend into the severing position, and any take up mechanism for receiving and carrying away severed portions, does not begin until after the severing position, so that neither delivery nor take up mechanisms extend into the plane containing the trajectory of the blade.

The depth of material that can be severed by the blade is determined by the increase in radius from the beginning to the end of the blade.

Typically this increase in radius is of the order of 140mm, thereby enabling material of up to that depth to be severed.

The increase in radius over the sawing segment of the blade may be the same as or different from the increase in radius over the cutting part of the blade.

In a preferred arrangement the rate of increase of radius per unit of angular displacement about the blade axis of rotation, is greater in the cutting part than in the sawing part of the blade.

Typically the rate of increase in the cutting part is twice that in the sawing part.

Where the increase in radius is to be substantially equal during the engagement of the material by each of the two parts, the circular extent of the sawing part will therefore have to be substantially twice the circular extent of the cutting part, if the rate of increase in radius in the cutting part is twice that in the sawing part.

The pitch of the teeth forming the sawing part of the blade is selected to be appropriate for the material to be cut.

In the case of meat on the bone, a tooth pitch in the range 3-8mm between points is usually appropriate, and a preferred pitch is 6mm.

It is usually desirable to form the teeth in the sawing part so that they are inclined at an angle to the plane of the blade, with the direction of the inclination alternating from one tooth to the next. When so formed the teeth are said to have a"set".

However, it has been found advantageous not to introduce a set into the teeth of the sawing part of the blade constructed in accordance with the present invention, so as to reduce the volume of debris created by the sawing process.

Although the other part of the blade has been described as performing a cutting function, it is to be understood that the edge of the blade need not be a continuous knife edge, and a scalloped knife edge may be provided so that the cutting is achieved by a series of knife edges separated by concave regions from which the blade material as been removed, the knife edges being circularly aligned so that each continues the cut made by the preceding knife edge. The spacing between the knife-edges may be linked to the increasing radius of the outer edge of the blade so that effectively a continuous knife-edge is presented to the material as the blade rotates.

Typically the knife-edges are formed by grinding two mutually inclined flats on the flank of the blade to define an equilateral triangle in cross section having an inclined angle at the blade periphery of the order of 200.

Typically the circular spacing between the leading point of each knife-edge and the next is of the order of 20mm.

A scalloped cutting edge has been found to have the advantage that any debris, particularly fat, created by the cuts will become lodged in the cutaway sections between the knifeedges, from where it can be removed by a cleaning station.

According to a further preferred feature of the invention each portion that is severed from the remainder of a log of material (e. g. a loin of pork) is supported in contact with the face of the remainder of the material, at least until the blade has passed completely through the material.

It has been found that in so doing debris scatter is restricted if not altogether prevented and debris, particularly from the sawing of brittle material, such as bone, is more reliably

retained in the gullets between the teeth in the saw part, and in the scallops between the knife edges in the cutting part, of the blade.

The support may be provided by at least one preceding cut portion which is restrained resiliently or in a controlled manner by a drive stop member, or by an escapement mechanism, and is prevented from freely advancing away from the severing position or falling forward so as to not be in a position to support the next portion to be cut.

Since material will be indexed forward into and through the cutting position (i. e. the plane of the blade) after the blade has exited from the material and before the leading end of the blade is to re-enter the material to make the next cut, the force required to index the material in the forward direction will also push any severed piece (s) ahead of it. It is therefore only necessary to provide an escapement mechanism acting with a small rearward force on the front face of the furthermost severed portion, to keep the severed portions in contact and the last severed portion in contact with the severed face of the following material, ready to maintain the same gentle rearward force between the severed face of the next portion to be severed and the new severed face of the following material, for the purpose aforesaid.

One simple form of escapement comprises a weighted pendulum which after being displaced by say 30 , will have lifted sufficiently to allow the foremost severed portion to pass under the lower end of the pendulum (or a pivoted lever linked thereto and movable therewith), so that the pendulum (or associated lever) can fall back to engage the front severed face of the next portion in the line, to press against it and provide the gentle rearward force, until that portion has in turn been pushed in a forward direction sufficient to allow it, in turn, to pass under the pendulum (or lever).

In accordance with another aspect of the invention an escapement mechanism can also be arranged to batch the portions, so that groups of similarly numbered portions (e. g. 2,3 or 4 per group) are allowed to become separated from the following portions, and travel as a

group forwardly away from the severing position, whilst leaving at least one portion behind.

The radially increasing periphery of the blade can be thought of as approximating to a socalled involute type of blade.

Preferably the periphery of each part of the blade (i. e. sawing and guillotining parts) describes part of a spiral.

If the radial increase per unit of angular displacement is the same in both parts, the two parts will lie on a single spiral.

If the radial increase per unit of angular displacement id different, the two curvatures will lie on two different spirals.

Preferably the delivery device by which material to be severed is moved towards the cutting position comprises a conveyor.

Typically the conveyor is in three sections, a loading conveyor for moving logs of material at a first linear speed until they lie on a second section, comprised of freely rotatable rollers which are not driven, and from which the logs are pushed from the rear as further logs are moved into contact by the loading conveyor, until each log over-runs onto the third section comprising a feed conveyor, which is driven but operated at a lower linear speed than the first conveyor, and whose motion is controlled in synchronism with the rotation of the blade, thereby to index material in a forward sense only when the sawing and guillotining parts of the blade are clear of the material.

The drive to the feed conveyor may be pulsed.

Normally in the case of pork loins they will be longer than the dead zone so that the first conveyor will have to be capable of matching the"pulsing"of the third conveyor when all the loins are in contact and the last loin has not left the first conveyor.

Preferably the material is sandwiched and lightly squeezed just prior to the cutting position, between a bridge member and the surface of the feed conveyor.

The bridge may be a fixed bar or roller or plurality of rollers or may comprise a supplementary endless belt conveyor, the bridge being resiliently forced by one or more springs or by air pressure acting on a piston in a cylinder so as to squeeze the material, and maintain substantially constant the thickness of the material relative to the surface of the feed conveyor, and therefore the depth of material which is to be severed by the blade.

Where one or more rollers or an endless belt supplementary conveyor is employed, the roller (s) or conveyor may be free running, so as to be rotated by movement of the material caused by the indexing of the feed conveyor.

Preferably however the roller (s) or supplementary conveyor is/are driven and preferably at a speed and in a direction and in synchronism with the pulse drive to the feed conveyor, so that there is no relative motion between the surface of the material and the roller (s) or supplementary conveyor.

Beyond the severing position, a deadplate may be provided onto which severed portions slide, preferably whilst remaining in the same attitude (e. g. upright) as when severed from the remaining material.

Beyond any deadplate, a powered transfer conveyor serves to receive portions pushed thereon ahead of portions stacking up on the deadplate, and to convey them away from the deadplate for sorting, grading, checking and/or packing.

The powered loading, feed and transfer conveyors may be driven by servo motors controlled by a control system, operated with feedback information from encoders, sensors and the like associated with the blade, a weighing station, scanning and/or inspection devices, and the like to control the motors so as to ensure logs of material are lined-up end to end upstream of the severing position and the leading end is indexed by the required distance between cuts, and the transfer conveyor operates at a suitable speed to remove portions at an appropriate rate for collating, checking etc. , and/or packing.

Preferably the distance between the bridge and the feed conveyor is adjustable to accommodate different materials of different mean thickness such as for example as between pork loins, legs of lamb and ribs of beef.

The loading and feed conveyors may be V-shaped to allow generally triangular cross section material to be reliably held in place laterally.

The V-shape may be formed by two co-operating endless belts.

Preferably the angle of one or both of the endless belts or other device (s), forming the Vshape, is or are adjustable to alter the included angle between the faces of the two belts or other device (s).

The invention will now be described by way of example with reference to the accompanying drawings, in which :- Fig 1 is a perspective diagrammatic view of apparatus for severing material of the type described, embodying various aspects of the present invention, Fig 2 is a plan view of the blade section of a tool for severing material of the type described, such as employed in the apparatus of Fig 1, and

Fig 3 is a plan view of part of the blade shown in Fig 1, to an enlarged scale, showing the tooth profile.

Detailed description of the drawings.

Fig 1 shows a meat severing apparatus for severing meat on the bone without creating smear on the faces of the cut portions and with reduced risk of bone chipping occurring.

A loin of pork 10 is carried by a conveyor assembly for feeding incrementally through a severing position at which the end of the loin therebeyond is severed from the remainder to form chops. The severing is achieved using a tool constructed in accordance with the invention and comprising a two part hub 12,14 between the two parts of which is sandwiched the inner periphery of an arcuate blade generally designated 16, but which itself comprises a knife edge section 18 and a saw edge section 20. The junction between the two section is denoted by the dotted line 24, although in practice this line would not be visible.

The blade is better seen in Fig 2. It is typically constructed from two arcuate sections 18 and 20 welded at 22. The weld line is ground away to leave a flush face on each side of the blade, and the blade is coated with a low friction material.

Around the outer periphery of section 18 a plurality of knife edges 24 are formed, typically at a 20mm pitch, and around the outer periphery of section 20 a plurality of teeth 26 are formed, typically at a 6mm pitch.

The radius of the inner periphery of each section is constant and the centre of curvature of that inner periphery is shown at 28. This is the centre of rotation for the blade. If the brittle material which is to be cut by the teeth 26 is in the lower part of the cross section of the loin of pork 10, the blade is rotated in the direction of the arrow 30, so that the upper part of the loin is cut through by the knife edges 24.

The blade 16 is attached to the hub 12,14 by means of screws which extend through holes around the hub part 12, one of which is denoted by reference numeral 32 and aligned holes around the blade 16, the corresponding one of which is denoted by reference numeral 34. The ends of the screws are received in tapped holes (not shown) in the other hub part 14 which align with the holes such as 32.

An inner region of each hub part 12,14 is of considerably increased thickness to form a collar 36 by which the hub can be mounted on a shaft 38 which is carried at opposite ends by bearings, one of which is shown at 40.

The shaft also carries a wheel 42 which is driven by a belt 44, itself driven by a wheel (not shown) carried on a second shaft 45 supported in bearings 46,48. Shaft 45 carries a third wheel 50 driven by a drive belt 52 from a wheel 54 carried by the output shaft of a drive motor 56.

The loin is first loaded onto a V-shaped loading conveyor 58 formed by two inclined endless belts 60,62, the inclined angle selected so as to accommodate the generally triangular cross sectional shape of the pork loin 10, so that the bone 64 is near the apex of the V. The conveyor 58 moves the loin in the direction of the arrow 66.

A free roller conveyor section 68 exists between the loading conveyor 58 and a feed conveyor 70 also formed by an inclined pair of endless belts only one of which is visible in Fig 1. The feed conveyor terminates just to the right hand side of the trajectory of the blade 16.

Beyond the blade trajectory is a dead plate 72 onto which cut pieces are pushed as the loin is indexed forward between cuts, and these cut portions fall onto and are carried away by a take up conveyor 74.

Two lateral supports straddle the feed conveyor 70, to constrain the pork loin ahead of the cutting region. One of these supports is shown at 76, The other (not shown) is similar.

Above the feed conveyor is an upper support conveyor 78 which is positioned at a height above the feed conveyor 70 such that the pork loin is lightly compressed between 78 and 70. The upper conveyor 78 runs at the same speed and at the same times as the feed conveyor 70, so as to positively drive the pork loin forwards towards the blade. The presents of the supports 76 and upper conveyor 78 constrains the pork loin to remain in a fixed position relative to the blade trajectory so that, apart from un-uniformity within each loin, and from one loin to another, the part of the loin section containing the bone will always occupy the vertex of the V section of the feed conveyor and will be a fixed distance below the conveyor 78.

The outer periphery of the blade 16 progressively diverges away from the inner periphery as between the end 80 and the end 82, so that with rotation about 28, the cutting edges 24 26 of the blade will progressively move down through the cutting station to cut through anything extending ahead of the feed conveyor 70 onto the dead plate 72. The rise of the cutting edge from 80 to 82 is typically of the order of 160mm so that material up to that thickness can be cut through.

Since it is now known where the boned region of the loin section is located, the saw tooth region 26 is arrange to have been rotated into the cutting position shortly prior to the level at which the cutting point would enter the boned region, so that from thereon, the cutting is achieved by the saw teeth 26.

Prior to this point, the loin can be guillotined and to this end the first part 24 of the blade 16 is formed with a series of knife-edges, which cut through the meat and fat of the loin with minimal waste. Any meat or fat picked up by the blade will tend to lodge between the knife-edge carrying segments, and between the teeth of the saw tooth section. Any such material is removed from the blade by a cleaning station 84. This may comprise a water or air jet and may include a brushing device and suction recovery device, so that the blade is fully cleared of debris before it re-enters the material to make the next cut.

The feed conveyor is operated intermittently so that the loin is indexed forward after the end 82 has left the loin and before the leading end of the blade 80 re-enters the loin. A control system (not shown) provides the control signal for controlling the conveyor drive including the time for which it operates and/or the speed of operation, so that the length of loin which extends beyond the blade trajectory after each indexing movement is the correct length to form an equal weight cut portion each time. Feedback signals from the control system may include a photocell based sensor such as 86 for detecting when the blade end 82 has left the loin, a shaft encoder (not shown) associated with the shaft 38, to provide angular information as to the position to which the blade has been rotated at any instant.

The blade 16 is supported just prior to entry by a pair of rollers 88,90 which are resiliently urged together to define a nip through which the blade passes. Each roller may be formed by a plurality of separate rolling elements to accommodate the different surface speeds of the blade, depending on the radial position where the roller engages the blade. The rolling elements may extend only over a sufficient length of each supporting axle (not shown) to just engage the blade between the hub parts 12,14 and the cutting edge of the blade, to prevent the rolling elements from being in contact with the teeth, so as to reduce wear on the rolling elements.

The rollers/rolling elements may be constructed from a food grade plastics material, or from stainless steel.

Fig 3 shows a part of the cutting edge of the blade, at the junction between the guillotining section and the sawing section.

The knife-edges are formed on the crests 92 of the teeth 94 and the spacing between crests is 20mm.

The 200 inclined angle of the triangular profile of the knife edge regions 92 is shown in Fig 3A, which shows the blade 16 as having a thickness of 0.6mm.

The saw teeth such as 96,98 have a pitch of 6mm, and to reduce waste, are not formed with a set.

Typically the knife edged teeth 94 extend around approximately 1/3 of the circular extent of the blade and the saw teeth extend around the remaining 2/3 of the blade.

Typically the rise in the cutting edge relative to the start point at end 80, up to the junction 100 between the knife edge section and the saw tooth section (see Fig 3) is equal to the rise between the junction 100 and the end of the blade 82. Therefore if the blade is rotated at constant speed, the cut through the first 50% of the depth of the loin section occurs in one half of the time allowed for the saw tooth section to cut through the remaining 50% of the loin section, which contains the bone.

Claims

Claims 1. A method of severing material of the type described comprising the steps of :- (1) delivering material to a severing position; (2) controlling the thickness of the material just upstream of the severing position so that the depth of material to be cut is prevented from exceeding a predetermined maximum dimension; (3) rotating a severing tool, part of the circumference of which includes a radially protruding blade part of which comprises a cutting segment and the remainder of which comprises a sawing segment, so that the blade passes through the severing position in a plane generally perpendicular to the direction in which material is fed thereto, so as to sever material on the downstream side of the blade trajectory from material upstream thereof; and (4) controlling the advance of material into the severing position in synchronism with rotation of the tool, so that material is only advanced after the blade has exited and before it re-enters the material.
2. A method as claimed in claim 1, wherein the material has a predictable cross section pattern of brittle and non-brittle (soft) material, and is arranged in the cutting position so that the brittle material will be cut before the soft material (or vice versa).
3. Apparatus for severing material of the type described comprising: (1) a delivery mechanism for delivering material to a cutting position; (2) an opening through which the material has to pass just upstream of the cutting position, which serves to control the depth of material in the cutting position; (3) a rotatable tool which includes a blade which extends partially around the tool and extends radially beyond a central circular region thereof, the tool being mounted for rotation in a plane generally perpendicular to the direction in which material is fed

<Desc/Clms Page number 21>

thereto, so that material downstream of the plane of the blade will be severed from that upstream of the plane of the blade, as the tool rotates through the cutting position; (4) a drive for rotating the tool; and (5) a control system for synchronising the delivery mechanism and the tool drive; wherein :- (6) the diameter of the central region of the tool is such that no contact occurs between the material and the central region of the tool, so that after the blade has been rotated through and beyond the material and before it re-enters the material to resume cutting, material upstream of the plane of the blade can be advanced into the cutting position ready for the next cut to be made; and (7) part of the blade comprises a cutting segment and the remainder comprises a sawing segment.
4. Apparatus as claimed in claim 3, wherein the tool is mounted so that an appropriate part of the blade enters and cuts through the cross section of the material ahead of the other part, so that brittle material will be cut by the sawing segment, and in general, non-brittle (soft) material will be cut by the cutting segment, of the blade.
5. Apparatus as claimed in claim 4 further comprising means for positioning the material relative to the blade so that the regions containing the brittle and non-brittle material respectively will be severed in succession one before the other.
6. Apparatus as claimed in claim 5 wherein the material is arranged so that the brittle material region will be the first to be severed and the non-brittle material region will comprise the second part to be severed.
7. Apparatus as claimed in any of claims 3 to 6 further comprising a viewing device such as a camera positioned to view the end face of each separate log of material before it reaches the severing position, means for processing signals therefrom to generate information indicative of the depth of the brittle material and means for generating a stop or divert signal to inhibit advance of that log to the severing position if information relating

<Desc/Clms Page number 22>

to the position and/or depth of the brittle material therein indicates the position or depth is incompatible with the depth to which the sawing part of the blade will penetrate, or the depth value is simply greater than a maximum permitted value.
8. Apparatus as claimed in any of claims 3 to 6 further comprising an ultrasound transmitter and receiver located upstream of the severing position, means for processing signals obtained from the receiver to generate information indicative of the depth and position of brittle material in the log of material to be severed, and means for generating a stop or divert signal to inhibit advance of that log to the cutting position if the ultrasound derived information indicates a position or depth of the brittle material which is incompatible with the depth to which the sawing segment of the blade will penetrate into

. erickl (-rncc ei- (, tirin nr thi-rien n n mnyimiim the material cross section, or the depth value is simply greater than a maximum permitted the Mat value.
9. Apparatus as claimed in claim 7 or 8 wherein a divert signal causes a delivery mechanism to divert a log to an inspection station, and allow the next log to take its place.
10. A rotatable tool for use in apparatus as claimed in any of claims 3 to 9 comprising a generally circular plate adapted to be mounted on a shaft of the apparatus for rotation about a notional centre, in which over a first sector the circumference increases radially with angular position from a starting datum, and a plurality of saw teeth are formed in its periphery in the first sector, and in a second sector, which follows the first sector in the direction of rotation, the circumference also continues to increase radially with angular position from the starting datum and a cutting or slicing profile is formed in its periphery, and over the remaining, third part of the circumference of the plate between the end of the second part and the starting datum, the plate is of substantially constant radius which is less than the smallest radius of the first part.
11. A tool as claimed in claim 10 wherein a radial step typically exists in the tool profile between the end of the second part and the beginning of the third part.

<Desc/Clms Page number 23>
12. A tool as claimed in claim 11 wherein a similar but smaller radial step exists in the tool profile between the end of the third part and the beginning of the first part, dictated by the difference in radius between the first and third parts.
13. A tool as claimed in any of claims 10 to 12 machined from a metal plate.
14. A tool as claimed in any of claims 10 to 12 constructed in two parts comprising a hub portion and an arcuate blade portion secured to the hub portion to radially extend therefrom around part of its circumference, and the region of the hub portion around which the arcuate blade does not extend comprises the said third part of the tool.
15. A tool as claimed in claim 14 wherein the hub is in two parts and the inner peripheral edge of the arcuate blade is sandwiched therebetween, and secured thereto by pins, bolts, nuts, rivets or by welding.
16. A tool as claimed in claim 14 or 15 wherein a quick release mechanism is provided so that the assembly of hub and blade as a whole, can be demounted, from the shaft, to allow for replacement.
17. A tool as claimed in claim 14 or 15 wherein a quick release mechanism is provided securing the blade to the hub so that the blade can be removed from the hub, and be replaced by a new blade, leaving the hub in position.
18. A tool as claimed in any of claims 12 to 17 wherein the blade is formed from a single arcuate sheet of metal.
19. A tool as claimed in any of claims 12 to 17 wherein the blade is formed from two arcuate segments welded end to end, with the weld surfaces dressed back to remove the weld line, to form a smooth surface on each side of the blade.

<Desc/Clms Page number 24>
20. A tool as claimed in any of claims 13 to 19 wherein the blade, or each segment of the blade, and any teeth or cutting elements along its edge, is/are be cut from strip or sheet steel using a laser cutting tool.
21. A tool as claimed in any of claims 13 to 20 wherein the blade is formed from highdensity stainless steel.
22. A tool as claimed in any of claims 13 to 21 wherein the blade thickness is 0. 6mm.
23. A tool as claimed in any of claims 13 to 20 wherein the blade is coated or impregnated with low friction material.
24. tool as claimed in any of claims 10 to 23 wherein the increase in radius over the sawing segment of the blade is the same as the increase in radius over the cutting part of the blade.
25. A tool as claimed in any of claims 10 to 23 wherein the increase in radius over the sawing segment of the blade is different from that over the cutting part of the blade.
26. A tool as claimed in claim 25 wherein the rate of increase of radius per unit of angular displacement about the blade axis of rotation, is greater in the cutting part than in the sawing part of the blade.
27. A tool as claimed in claim 26 wherein the rate of increase in the cutting part is twice that in the sawing part.
28. A tool as claimed in claim 27 wherein the circular extent of the sawing part is substantially twice the circular extent of the cutting part, so that the rate of increase in radius in the cutting part is twice that in the sawing part.

<Desc/Clms Page number 25>
29. A tool as claimed in any of claims 10 to 28 for cutting meat on the bone, in which the tooth pitch is in the range 3-8mm, preferably 6 mm, between points.
30. A tool as claimed in any of claims 10 to 29 wherein the teeth in the sawing part are inclined at an angle to the plane of the blade, with the direction of the inclination alternating from one tooth to the next.
31. A tool as claimed in any of claims 10 to 29 wherein the teeth of the sawing part of the blade are not inclined to the plane of the blade, so are not formed with a set, so as to reduce the volume of debris created by the sawing process.
32. A tool as claimed in any of claims 10 to 31 wherein the part of the blade performing a cutting function is a continuous knife edge.
33. A tool as claimed in any of claims 10 to 31 wherein the cutting edge of the blade is formed as a scalloped knife edge so that the cutting is achieved by a series of knife edges separated by concave regions from which the blade material as been removed.
34. A tool as claimed in claim 33 wherein the separate knife edges are circularly aligned so that each continues the cut made by the preceding knife edge.
35. A tool as claimed in claim 34 wherein the spacing between the knife-edges is linked to the increasing radius of the outer edge of the blade so that effectively a continuous knifeedge is presented to the material as the blade rotates.
36. A tool as claimed in any of claims 33 to 35 wherein the knife-edges are formed by grinding two mutually inclined flats on the flank of the blade to define an equilateral triangle in cross section having an inclined angle at the blade periphery of the order of 200.
37. A tool as claimed in any of claims 33 to 36 wherein the circular spacing between the leading point of each knife-edge and the next is of the order of 20mm.

<Desc/Clms Page number 26>
38. A tool as claimed in any of claims 10 to 37 wherein the radially increasing periphery of the blade approximates to a so-called involute type of blade.
39. A tool as claimed in any of claims 10 to 37 wherein the periphery of each part of the blade (i. e. sawing and guillotining parts) describes part of a spiral.
40. Apparatus as claimed in any of claims 3 to 9 when fitted with a tool as claimed in any of claims 10 to 39.
41. Apparatus as claimed in claim 40 wherein means is provided to support the blade at least in the region of the point of entry into the material to be cut.
42. Apparatus as claimed in claim 41 wherein means is also provided to support the blade where it exits from the material.
43. Apparatus as claimed in claim 41 or 42 wherein the support comprises a pair of elements forming a nip between which the blade passes as it rotates into and/or out of contact with the material.
44. Apparatus as claimed in claim 43 wherein the nip preferably exerts a resilient grip on the blade.
45. Apparatus as claimed in claim 43 or 44 wherein the elements forming the nip comprise two rollers adapted to rotate about two spaced apart axes which are resiliently urged together.
46. Apparatus as claimed in claim 45 wherein the axes extend in a radial sense relative to the axis around which the blade rotates.
47. Apparatus as claimed in claim 45 wherein the rollers are frusto conical, and the two axes are mutually inclined to bring the two frusto conical surfaces in contact with opposite

<Desc/Clms Page number 27>

faces of the blade, the angle of the cone being chosen so that there is no relative motion between the surface of the blade and the rollers
48. Apparatus as claimed in any of claims 42 to 47 wherein the support elements extend between the circumference of the hub and beyond the outermost radius of the blade.
49. Apparatus as claimed in any of claims 42 to 47 wherein the support elements only extend beyond the hub by a radial distance which is less than the smallest radius of the blade, so that any toothed peripheral region of the blade will always lie radially beyond the ends of the support elements, so that the teeth will not wear down the elements.
50. Apparatus as claimed in any of claims 42 to 49 wherein the radial position of the support elements is adjustable relative to the axis of rotation of the tool.
51. Apparatus as claimed in claim 50 wherein the support elements are movable inwardly and outwardly in a generally radial sense, by a drive means, which synchronously radially moves the support elements in and out so as to grip a region of the blade which is always close to its sawing or cutting edge.
52. Apparatus as claimed in claim 51 wherein the drive means moves the support elements outwardly to follow the radially increasing sawing and cutting edge, and after the end of the blade has passed, it moves the support elements in a generally radial manner back to be in the correct position to receive the beginning of the blade once again.
53. Apparatus as claimed in any of claims 42 to 52 wherein the support elements are formed from a food-grade plastics material or from stainless steel.
54. Apparatus as claimed in any of claims 42 to 53 wherein a blade cleaning station is provided to remove debris from the blade after it has exited from the material and before it re-enters the material to make the next cut.

<Desc/Clms Page number 28>
55. Apparatus as claimed in claim 54 wherein the blade cleaning station comprises an air jet, a water jet, a brush, or any combination thereof.
56. Apparatus as claimed in claim 55 wherein the cleaning station is located clear of the material to be cut at a position around the blade trajectory at which there is no tendency for debris removed thereby to find its way back onto the material waiting to be cut, or onto cut pieces downstream of the cutting position.
57. Apparatus as claimed in any of claims 54 to 56 wherein the cleaning station is adapted to remove material lodged between the teeth of the blade
58. Apparatus as claimed in claim 54 wherein the cleaning station comprises an air jet or water jet acting in a direction generally perpendicular to the plane of the blade, to remove material from between the teeth.
59. Apparatus as claimed in any of claims 54 to 58 wherein the cleaning station includes a debris collecting device, typically including suction, to collect debris that has been removed from the blade.
60. Apparatus as claimed in any of claims 3 to 9 or 40 to 59 wherein the axis about which the tool rotates is adjustable so as to increase or decrease the distance between it and a surface of the delivery device on which the material to be cut rests.
61. Apparatus as claimed in claim 60 wherein additionally the tool axis of rotation is adjustable laterally relative to the surface on which the material rests when protruding into the severing position.
62. Apparatus as claimed in claim 60 or 61 wherein the adjustment is manually controllable to enable the apparatus to be set up for a particular type of material, or is actively controlled during cutting, under the control of an operator viewing the material being cut, or by control signals from a control system supplied with signals from a vision system set

<Desc/Clms Page number 29>

to inspect the face of severed material (or material to be severed), or by control signals from an ultrasonic system set to determine depth and/or position and/or size of brittle material in material waiting to be severed.
63. Apparatus as claimed in any of claims 3 to 9 or 38 to 62 further comprising means for supporting each portion that is severed from the remainder of a log of material so that the cut face remains in contact with the face of the remainder of the material, at least until the blade has passed completely through the material, so as to reduce debris scatter when sawing brittle material, such as bone, and retain the debris in the gullets between the teeth in the saw part, and in the scallops between the knife edges in the cutting part, of the blade.
64. Apparatus as claimed in claim 63, wherein the support is provided by at least one preceding cut portion and means is provided to restrain such said cut portion resiliently or in a controlled manner by a drive stop member, or by an escapement mechanism, to prevent it from freely advancing away from the severing position or falling forward so as to not be in a position to support the next portion to be cut.
65. Apparatus as claimed in claim 64 wherein an escapement comprises a weighted pendulum which after being displaced by a given angle, will have lifted sufficiently to allow the foremost severed portion to pass either under the lower end of the pendulum or a pivoted lever linked thereto and movable therewith, so that the pendulum (or associated lever) can fall back to engage the front severed face of the next portion in the line, to press against it and provide a rearward force, until that portion has in turn been pushed in a forward direction sufficient to allow it, in turn, to pass under the pendulum (or lever).
66. Apparatus as claimed in any of claims 3 to 9 or 40 to 62 wherein the delivery device by which material to be severed is moved towards the cutting position comprises a conveyor.

<Desc/Clms Page number 30>
67. Apparatus as claimed in claim 66 wherein the conveyor is in three sections, a loading conveyor for moving logs of material at a first linear speed until they lie on a second section, comprised of freely rotatable rollers which are not driven, and from which the logs are pushed from the rear as further logs are moved into contact by the loading conveyor, until each log over-runs onto the third section comprising a feed conveyor, which is driven but operated at a lower linear speed than the first conveyor, and whose motion is controlled in synchronism with the rotation of the blade, thereby to index material in a forward sense only when the sawing and guillotining parts of the blade are clear of the material.
68. Apparatus as claimed in claim 67 wherein drive to the feed conveyor is be pulsed.
69. Apparatus as claimed in claim 67 or 68 wherein the material is sandwiched and lightly squeezed just prior to the cutting position, between a bridge member and the surface of the feed conveyor.
70. Apparatus as claimed in claim 69 wherein the bridge is a fixed bar or roller or plurality of rollers or comprises a supplementary endless belt conveyor, and the bridge is resiliently forced by one or more springs or by air pressure acting on a piston in a cylinder so as to squeeze the material thereby to maintain substantially constant the thickness of the material relative to the surface of the feed conveyor, and therefore the depth of material which is to be severed by the blade.
71. Apparatus as claimed in claim 69 in which one or more rollers or an endless belt supplementary conveyor is employed as the bridge.
72. Apparatus as claimed in claim 71 wherein the roller (s) or conveyor are free running, so as to be rotated by movement of the material caused by the indexing of the feed conveyor.
73. Apparatus as claimed in claim 71 wherein the roller (s) or supplementary conveyor is/are driven, at a speed and in a direction and in synchronism with the pulse drive to the

<Desc/Clms Page number 31>

feed conveyor, so that there is substantially no relative motion between the surface of the material and the roller (s) or supplementary conveyor.
74. Apparatus as claimed in any of claims 66 to 73 wherein beyond the severing position, a deadplate may be provided onto which severed portions slide, whilst remaining in the same attitude (e. g. upright) as when severed from the remaining material.
75. Apparatus as claimed in claim 74 wherein beyond the deadplate, a powered transfer conveyor serves to receive portions pushed thereon ahead of portions stacking up on the deadplate, to convey them away from the deadplate for sorting, grading, checking and/or packing.
76. Apparatus as claimed in claim 75 wherein the loading, feed and transfer conveyors are driven by servo motors controlled by a control system, operated with feedback information from encoders, sensors and the like associated with the blade, and/or from a weighing station, and/or from a scanning and/or inspection device, to control the motors so as to ensure that logs of material are lined-up end to end upstream of the severing position and that the leading end is indexed by the required distance between cuts, and that the transfer conveyor operates at a suitable speed to remove portions at an appropriate rate for collating, checking and/or packing.
77. Apparatus as claimed in any of claims 69 to 76 wherein the distance between the bridge and the feed conveyor is adjustable to accommodate different materials of different mean thickness such as for example as between pork loins, legs of lamb and ribs of beef.
78. Apparatus as claimed in any of claims 67 to 77 wherein the loading and feed conveyors are V-shaped to allow generally triangular cross section material to be reliably held in place laterally.
79. Apparatus as claimed in claim 78 wherein the V-shape is formed by two cooperating endless belts.

<Desc/Clms Page number 32>
80. Apparatus as claimed in claim 79 wherein the angle of one or both of the endless belts or other device (s), forming the V-shape, is or are adjustable to alter the included angle between the faces of the two belts or other device (s).

80. Apparatus as claimed in claim 79 wherein the angle of one or both of the endless belts or other device (s), forming the V-shape, is or are adjustable to alter the included angle between the faces of the two belts or other device (s).

<Desc/Clms Page number 33>

Amended claims have been filed as follows

1. A method of severing material of the type described comprising the steps of :- (1) delivering material to a severing position; (2) controlling the thickness of the material just upstream of the severing position so that the depth of material to be cut is prevented from exceeding a predetermined maximum dimension; (3) rotating a severing tool, part of the circumference of which includes a radially protruding blade part of which comprises a cutting segment and the remainder of which comprises a sawing segment, so that the blade passes through the severing position in a plane generally perpendicular to the direction in which material is fed thereto, so as to sever material on the downstream side of the blade trajectory from material upstream thereof; and (4) controlling the advance of material into the severing position in synchronism with rotation of the tool, so that material is only advanced after the blade has exited and before it re-enters the material.

2. A method as claimed in claim 1, wherein the material has a predictable cross section pattern of brittle and non-brittle (soft) material, and is arranged in the cutting position so that the brittle material will be cut before the soft material (or vice versa).

3. Apparatus for severing material of the type described comprising: (1) a delivery mechanism for delivering material to a cutting position; (2) an opening through which the material has to pass just upstream of the cutting position, which serves to control the depth of material in the cutting position; (3) a rotatable tool which includes a blade which extends partially around the tool and extends radially beyond a central circular region thereof, the tool being mounted for rotation in a plane generally perpendicular to the direction in which material is fed

<Desc/Clms Page number 34>

thereto, so that material downstream of the plane of the blade will be severed from that upstream of the plane of the blade, as the tool rotates through the cutting position; (4) a drive for rotating the tool; and (5) a control system for synchronising the delivery mechanism and the tool drive; wherein :- (6) the diameter of the central region of the tool is such that no contact occurs between the material and the central region of the tool, so that after the blade has been rotated through and beyond the material and before it re-enters the material to resume cutting, material upstream of the plane of the blade can be advanced into the cutting position ready for the next cut to be made; and (7) part of the blade comprises a cutting segment and the remainder comprises a sawing segment.

4. Apparatus as claimed in claim 3, wherein the tool is mounted so that an appropriate part of the blade enters and cuts through the cross section of the material ahead of the other part, so that brittle material will be cut by the sawing segment, and in general, non-brittle (soft) material will be cut by the cutting segment, of the blade.

5. Apparatus as claimed in claim 4 further comprising means for positioning the material relative to the blade so that the regions containing the brittle and non-brittle material respectively will be severed in succession one before the other.

6. Apparatus as claimed in claim 5 wherein the material is arranged so that the brittle material region will be the first to be severed and the non-brittle material region will comprise the second part to be severed.

7. Apparatus as claimed in any of claims 3 to 6 further comprising a viewing device such as a camera positioned to view the end face of each separate log of material before it reaches the severing position, means for processing signals therefrom to generate information indicative of the depth of the brittle material and means for generating a stop or divert signal to inhibit advance of that log to the severing position if information relating

<Desc/Clms Page number 35>

to the position and/or depth of the brittle material therein indicates the position or depth is incompatible with the depth to which the sawing part of the blade will penetrate, or the depth value is simply greater than a maximum permitted value.

8. Apparatus as claimed in any of claims 3 to 6 further comprising an ultrasound transmitter and receiver located upstream of the severing position, means for processing signals obtained from the receiver to generate information indicative of the depth and position of brittle material in the log of material to be severed, and means for generating a stop or divert signal to inhibit advance of that log to the cutting position if the ultrasound derived information indicates a position or depth of the brittle material which is incompatible with the depth to which the sawing segment of the blade will penetrate into the material cross section, or the depth value is simply greater than a maximum permitted value.

9. Apparatus as claimed in claim 7 or 8 wherein a divert signal causes a delivery mechanism to divert a log to an inspection station, and allow the next log to take its place.

10. A rotatable tool for use in apparatus as claimed in any of claims 3 to 9 comprising a generally circular plate adapted to be mounted on a shaft of the apparatus for rotation about a notional centre, in which over a first sector the circumference increases radially with angular position from a starting datum, and a plurality of saw teeth are formed in its periphery in the first sector, and in a second sector, which follows the first sector in the direction of rotation, the circumference also continues to increase radially with angular position from the starting datum and a cutting or slicing profile is formed in its periphery, and over the remaining, third part of the circumference of the plate between the end of the second part and the starting datum, the plate is of substantially constant radius which is less than the smallest radius of the first part.

11. A tool as claimed in claim 10 wherein a radial step typically exists in the tool profile between the end of the second part and the beginning of the third part.

<Desc/Clms Page number 36>

12. A tool as claimed in claim 11 wherein a similar but smaller radial step exists in the tool profile between the end of the third part and the beginning of the first part, dictated by the difference in radius between the first and third parts.

13. A tool as claimed in any of claims 10 to 12 machined from a metal plate.

14. A tool as claimed in any of claims 10 to 12 constructed in two parts comprising a hub portion and an arcuate blade portion secured to the hub portion to radially extend therefrom around part of its circumference, and the region of the hub portion around which the arcuate blade does not extend comprises the said third part of the tool.

15. A tool as claimed in claim 14 wherein the hub is in two parts and the inner peripheral edge of the arcuate blade is sandwiched therebetween, and secured thereto by pins, bolts, nuts, rivets or by welding.

16. A tool as claimed in claim 14 or 15 wherein a quick release mechanism is provided so that the assembly of hub and blade as a whole, can be demounted, from the shaft, to allow for replacement.

17. A tool as claimed in claim 14 or 15 wherein a quick release mechanism is provided securing the blade to the hub so that the blade can be removed from the hub, and be replaced by a new blade, leaving the hub in position.

18. A tool as claimed in any of claims 12 to 17 wherein the blade is formed from a single arcuate sheet of metal.

19. A tool as claimed in any of claims 12 to 17 wherein the blade is formed from two arcuate segments welded end to end, with the weld surfaces dressed back to remove the weld line, to form a smooth surface on each side of the blade.

<Desc/Clms Page number 37>

20. A tool as claimed in any of claims 13 to 19 wherein the blade, or each segment of the blade, and any teeth or cutting elements along its edge, is/are be cut from strip or sheet steel using a laser cutting tool.

21. A tool as claimed in any of claims 13 to 20 wherein the blade is formed from high- density stainless steel.

22. A tool as claimed in any of claims 13 to 21 wherein the blade thickness is 0. 6mm.

23. A tool as claimed in any of claims 13 to 20 wherein the blade is coated or impregnated with low friction material.

24. A tool as claimed in any of claims 10 to 23 wherein the increase in radius over the sawing segment of the blade is the same as the increase in radius over the cutting part of the blade.

25. A tool as claimed in any of claims 10 to 23 wherein the increase in radius over the sawing segment of the blade is different from that over the cutting part of the blade.

26. A tool as claimed in claim 25 wherein the rate of increase of radius per unit of angular displacement about the blade axis of rotation, is greater in the cutting part than in the sawing part of the blade.

27. A tool as claimed in claim 26 wherein the rate of increase in the cutting part is twice that in the sawing part.

28. A tool as claimed in nay of claims 10 to 23 wherein the circular extent of the sawing part of the blade is substantially twice the circular extent of the cutting part of the blade, and the rate of increase in radius in the cutting part is twice that in the sawing part.

<Desc/Clms Page number 38>

29. A tool as claimed in any of claims 10 to 28 for cutting meat on the bone, in which the tooth pitch is in the range 3-8mm, preferably 6 mm, between points.

30. A tool as claimed in any of claims 10 to 29 wherein the teeth in the sawing part are inclined at an angle to the plane of the blade, with the direction of the inclination alternating from one tooth to the next 31. A tool as claimed in any of claims 10 to 29 wherein the teeth of the sawing part of the blade are not inclined to the plane of the blade, so are not formed with a set, so as to reduce the volume of debris created by the sawing process.

1 t) ±'I 111--F +I,an. in any o'claims L\./LU Jk w L-e-n +I,--t ad 32. A tool as claimed in any of claims 10 to 31 wherein the pan of the blade performing a cutting function is a continuous knife edge.

33. A tool as claimed in any of claims 10 to 31 wherein the cutting edge of the blade is formed as a scalloped knife edge so that the cutting is achieved by a series of knife edges separated by concave regions from which the blade material as been removed.

34. A tool as claimed in claim 33 wherein the separate knife edges are circularly aligned so that each continues the cut made by the preceding knife edge.

35. A tool as claimed in claim 34 wherein the spacing between the knife-edges is linked to the increasing radius of the outer edge of the blade so that effectively a continuous knifeedge is presented to the material as the blade rotates.

36. A tool as claimed in any of claims 33 to 35 wherein the knife-edges are formed by grinding two mutually inclined flats on the flank of the blade to define an equilateral triangle in cross section having an inclined angle at the blade periphery of the order of 200.

37. A tool as claimed in any of claims 33 to 36 wherein the circular spacing between the leading point of each knife-edge and the next is of the order of 20mm

<Desc/Clms Page number 39>

38. A tool as claimed in any of claims 10 to 37 wherein the radially increasing periphery of the blade approximates to a so-called involute type of blade.

39. A tool as claimed in any of claims 10 to 37 wherein the periphery of each part of the blade (i. e. sawing and guillotining parts) describes part of a spiral.

40. Apparatus as claimed in any of claims 3 to 9 when fitted with a tool as claimed in any of claims 10 to 39.

41. Apparatus as claimed in claim 40 wherein means is provided to support the blade at least in the region of the point of entry into the material to be cut.

42. Apparatus as claimed in claim 41 wherein means is also provided to support the blade where it exits from the material.

43. Apparatus as claimed in claim 41 or 42 wherein the support comprises a pair of elements forming a nip between which the blade passes as it rotates into and/or out of contact with the material.

44. Apparatus as claimed in claim 43 wherein the nip preferably exerts a resilient grip on the blade.

45. Apparatus as claimed in claim 43 or 44 wherein the elements forming the nip comprise two rollers adapted to rotate about two spaced apart axes which are resiliently urged together.

46. Apparatus as claimed in claim 45 wherein the axes extend in a radial sense relative to the axis around which the blade rotates.

47. Apparatus as claimed in claim 45 wherein the rollers are frusto conical, and the two axes are mutually inclined to bring the two frusto conical surfaces in contact with opposite

<Desc/Clms Page number 40>

faces of the blade, the angle of the cone being chosen so that there is no relative motion between the surface of the blade and the rollers 48. Apparatus as claimed in any of claims 42 to 47 wherein the support elements extend between the circumference of the hub and beyond the outermost radius of the blade.

49. Apparatus as claimed in any of claims 42 to 47 wherein the support elements only extend beyond the hub by a radial distance which is less than the smallest radius of the blade, so that any toothed peripheral region of the blade will always lie radially beyond the ends of the support elements, so that the teeth will not wear down the elements.

50. ~Annnrntiicz nz L-1iimpri in aT of A2'-^AD adal o LILIL% L IA.

Y 50. Apparatus as claimed in any of claims 42 to 49 wherein the radial position of the support elements is adjustable relative to the axis of rotation of the tool.

51. Apparatus as claimed in claim 50 wherein the support elements are movable inwardly and outwardly in a generally radial sense, by a drive means, which synchronously radially moves the support elements in and out so as to grip a region of the blade which is always close to its sawing or cutting edge.

52. Apparatus as claimed in claim 51 wherein the drive means moves the support elements outwardly to follow the radially increasing sawing and cutting edge, and after the end of the blade has passed, it moves the support elements in a generally radial manner back to be in the correct position to receive the beginning of the blade once again.

53. Apparatus as claimed in any of claims 42 to 52 wherein the support elements are formed from a food-grade plastics material or from stainless steel.

54. Apparatus as claimed in any of claims 42 to 53 wherein a blade cleaning station is provided to remove debris from the blade after it has exited from the material and before it re-enters the material to make the next cut.

<Desc/Clms Page number 41>

55. Apparatus as claimed in claim 54 wherein the blade cleaning station comprises an air jet, a water jet, a brush, or any combination thereof.

56. Apparatus as claimed in claim 55 wherein the cleaning station is located clear of the material to be cut at a position around the blade trajectory at which there is no tendency for debris removed thereby to find its way back onto the material waiting to be cut, or onto cut pieces downstream of the cutting position.

57. Apparatus as claimed in any of claims 54 to 56 wherein the cleaning station is adapted to remove material lodged between the teeth of the blade

58. Apparatus as claimed in claim 54 wherein the cleaning station comprises an air jet or water jet acting in a direction generally perpendicular to the plane of the blade, to remove material from between the teeth.

59. Apparatus as claimed in any of claims 54 to 58 wherein the cleaning station includes a debris collecting device, typically including suction, to collect debris that has been removed from the blade.

60. Apparatus as claimed in any of claims 3 to 9 or 40 to 59 wherein the axis about which the tool rotates is adjustable so as to increase or decrease the distance between it and a surface of the delivery device on which the material to be cut rests.

61. Apparatus as claimed in claim 60 wherein additionally the tool axis of rotation is adjustable laterally relative to the surface on which the material rests when protruding into the severing position.

62. Apparatus as claimed in claim 60 or 61 wherein the adjustment is manually controllable to enable the apparatus to be set up for a particular type of material, or is actively controlled during cutting, under the control of an operator viewing the material being cut, or by control signals from a control system supplied with signals from a vision system set

<Desc/Clms Page number 42>

to inspect the face of severed material (or material to be severed), or by control signals from an ultrasonic system set to determine depth and/or position and/or size of brittle material in material waiting to be severed.

63. Apparatus as claimed in any of claims 3 to 9 or 38 to 62 further comprising means for supporting each portion that is severed from the remainder of a log of material so that the cut face remains in contact with the face of the remainder of the material, at least until the blade has passed completely through the material, so as to reduce debris scatter when sawing brittle material, such as bone, and retain the debris in the gullets between the teeth in the saw part, and in the scallops between the knife edges in the cutting part, of the blade.

64. Apparatus as claimed in claim 63, wherein the support is provided by at least one preceding cut portion and means is provided to restrain such said cut portion resiliently or in a controlled manner by a drive stop member, or by an escapement mechanism, to prevent it from freely advancing away from the severing position or falling forward so as to not be in a position to support the next portion to be cut.

65. Apparatus as claimed in claim 64 wherein an escapement comprises a weighted pendulum which after being displaced by a given angle, will have lifted sufficiently to allow the foremost severed portion to pass either under the lower end of the pendulum or a pivoted lever linked thereto and movable therewith, so that the pendulum (or associated lever) can fall back to engage the front severed face of the next portion in the line, to press against it and provide a rearward force, until that portion has in turn been pushed in a forward direction sufficient to allow it, in turn, to pass under the pendulum (or lever).

66. Apparatus as claimed in any of claims 3 to 9 or 40 to 62 wherein the delivery device by which material to be severed is moved towards the cutting position comprises a conveyor.

<Desc/Clms Page number 43>

67-Apparatus as claimed in claim 66 wherein the conveyor is in three sections, a loading conveyor for moving logs of material at a first linear speed until they lie on a second section, comprised of freely rotatable rollers which are not driven, and from which the logs are pushed from the rear as further logs are moved into contact by the loading conveyor, until each log over-runs onto the third section comprising a feed conveyor, which is driven but operated at a lower linear speed than the first conveyor, and whose motion is controlled in synchronism with the rotation of the blade, thereby to index material in a forward sense only when the sawing and guillotining parts of the blade are clear of the material.

68. Apparatus as claimed in claim 67 wherein drive to the feed conveyor is be pulsed.

69. Apparatus as claimed in claim 67 or 68 wherein the material is sandwiched and lightly squeezed just prior to the cutting position, between a bridge member and the surface of the feed conveyor.

70. Apparatus as claimed in claim 69 wherein the bridge is a fixed bar or roller or plurality of rollers or comprises a supplementary endless belt conveyor, and the bridge is resiliently forced by one or more springs or by air pressure acting on a piston in a cylinder so as to squeeze the material thereby to maintain substantially constant the thickness of the material relative to the surface of the feed conveyor, and therefore the depth of material which is to be severed by the blade.

71. Apparatus as claimed in claim 69 in which one or more rollers or an endless belt supplementary conveyor is employed as the bridge.

72. Apparatus as claimed in claim 71 wherein the roller (s) or conveyor are free running, so as to be rotated by movement of the material caused by the indexing of the feed conveyor.

73. Apparatus as claimed in claim 71 wherein the roller (s) or supplementary conveyor is/are driven, at a speed and in a direction and in synchronism with the pulse drive to the

<Desc/Clms Page number 44>

feed conveyor, so that there is substantially no relative motion between the surface of the material and the roller (s) or supplementary conveyor.

74. Apparatus as claimed in any of claims 66 to 73 wherein beyond the severing position, a deadplate may be provided onto which severed portions slide, whilst remaining in the same attitude (e. g. upright) as when severed from the remaining material.

75. Apparatus as claimed in claim 74 wherein beyond the deadplate, a powered transfer conveyor serves to receive portions pushed thereon ahead of portions stacking up on the deadplate, to convey them away from the deadplate for sorting, grading, checking and/or packing.

76. Apparatus as claimed in claim 75 wherein the loading, feed and transfer conveyors are driven by servo motors controlled by a control system, operated with feedback information from encoders, sensors and the like associated with the blade, and/or from a weighing station, and/or from a scanning and/or inspection device, to control the motors so as to ensure that logs of material are lined-up end to end upstream of the severing position and that the leading end is indexed by the required distance between cuts, and that the transfer conveyor operates at a suitable speed to remove portions at an appropriate rate for collating, checking and/or packing.

77. Apparatus as claimed in any of claims 69 to 76 wherein the distance between the bridge and the feed conveyor is adjustable to accommodate different materials of different mean thickness such as for example as between pork loins, legs of lamb and ribs of beef.

78. Apparatus as claimed in any of claims 67 to 77 wherein the loading and feed conveyors are V-shaped to allow generally triangular cross section material to be reliably held in place laterally.

79. Apparatus as claimed in claim 78 wherein the V-shape is formed by two co-operating endless belts.

<Desc/Clms Page number 45>