Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14B—MECHANICAL TREATMENT OR PROCESSING OF SKINS, HIDES OR LEATHER IN GENERAL; PELT-SHEARING MACHINES; INTESTINE-SPLITTING MACHINES
  • C14B1/00—Manufacture of leather; Machines or devices therefor
  • C14B1/02—Fleshing, unhairing, samming, stretching-out, setting-out, shaving, splitting, or skiving skins, hides, or leather
  • C14B1/14—Fleshing, unhairing, samming, stretching-out, setting-out, shaving, splitting, or skiving skins, hides, or leather using tools cutting the skin in a plane substantially parallel to its surface
  • C14B1/18—Fleshing, unhairing, samming, stretching-out, setting-out, shaving, splitting, or skiving skins, hides, or leather using tools cutting the skin in a plane substantially parallel to its surface using band knives
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14B—MECHANICAL TREATMENT OR PROCESSING OF SKINS, HIDES OR LEATHER IN GENERAL; PELT-SHEARING MACHINES; INTESTINE-SPLITTING MACHINES
  • C14B17/00—Details of apparatus or machines for manufacturing or treating skins, hides, leather, or furs
  • C14B17/14—Auxiliary devices for leather-working machines, e.g. grinding devices for blading cylinders or dust-removal devices combined with the working machines

Definitions

• This invention relates to an improved shearing unit, more particularly for a unit for the removal of a fleece from a sheep or from the pelt by the use of a continuously moving cutting blade.
• a shearing unit for shearing wool from a pelt or skin of a sheep comprising a head having an endless cutting blade, characterized in that said endless cutting blade is provided with a serrated cutting edge such that at cutting speeds in the range of 500 to 3,000 metres per minute the serrated edge cuts the wool.
• the term "serrated edge” is intended to mean an edge having a roughness similar to that produced by grinding with a stone having a grit size between 30 and 120 grit.
• the edge of the blade is treated with a selected stone during the process of removal of the wool from the skin or pelt to maintain its cutting efficiency. This is achieved by applying a stone to the blade by rotating the stone at a peripheral speed and at the required angle of presentation of the stone to the blade to produce the desired angle of serrations to engage the fibres.
• an improved shearing unit for removing wool from a skin, the unit including a shearing head, an endless cutting blade passing through the head, a grinding disc or wheel, and means for applying the grinding disc or wheel to the blade to provide the blade with a serrated cutting edge, characterized in that the grinding disc or wheel has an internal reinforcement for rotation at a high peripheral speed, and also having a bond and grit such that the grinding disc or wheel will wear at a rate to substantially prevent the build-up of lanolin in the wheel or disc.
• the required speed of the cutting blade is in the order of 500 to 3,000 metres per minute, preferably about 1 ,500 metres per minute and in order to produce a serration approximately perpendicular to the edge of the blade a particular range of peripheral speeds of the grinding disc is required to be produced. It is therefore required that the bonding properties of this disc or stone will allow the wheel to be safely rotated at this speed.
• the required hardness or strength of the bond is assisted by the incorporation of special fibres in the body of the wheel thus allowing a high peripheral speed to be used.
• the cutting blade is a special hard saw blade grade steel.
• the standard specification of grit for grinding this type of steel is normally regular aluminium oxide which is tough and not easily fractured.
• Silicon carbide grit is harder but more easily fractured.
• the silicon carbide wheel is used for grinding materials of low tensile strength, that is, marble, masonry etc. since the silicon carbide thus fractures more readily thus exposing more cutting edges.
• the silicon carbide disc or alternatively a modified aluminium oxide which is intermediate between the regular aluminium oxide and the silicon carbide is used, and the required rate of fracturing of the grits associated with the strength of the bond is varied to the requirement by controlling the pressure and length of application of the disc to the blade.
• An air cylinder is employed to move the grinding disc to make contact between the disc and the blade.
• the pressure of contact is controlled while the pressure of the air cylinder and the pressure regulator is used to vary this pressure.
• the frequency and period of application of the grinding disc being under the control of a control unit to periodically apply the disc to the blade.
• a grinding disc is used having a reinforced fibre to allow the high speeds required.
• a silicon carbide or the modified aluminium oxide grit is used of coarse grain size ranging from 30 to 120, preferably 40.
• the hardness grade of the bond can vary from medium to hard, that is, from L to R grade, preferably 0, the bond being of a rubber or resinoid type with a porosity structure from 2 to 8, preferably 5.
• the invention in a preferred form, utilizes a grinding disc for the production of a cutting edge on a high carbon steel blade by the use of a grinding disc having a silicon carbide or a modified aluminium oxide grit which is not usually used or recommended to use on such a steel, this having a coarse grain size to provide a serrated cutting edge, the bond being such that after fracturing of the grit to provide a further cutting edge, the grit is more readily removed from the disc to expose further grit to thus provide a sufficient rate of wear of the grinding disc to eliminate or minimize the build-up of lanolin on the disc.
• an improved shearing unit with a continuously moving cutting blade of an endless nature in which the blade is periodically sharpened by a grinding wheel or disc having a reinforced bond to hold the grit so that the wheel or disc will rotate at very high speeds and yet the bond and grit being of such a nature that it will wear away at a rate to prevent any substantial build-up of lanolin or grease on the wheel which build-up would then reduce the effectiveness of the grinding wheel or disc.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Crushing And Pulverization Processes (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3771463

Family Applications (1)

Country Status (3)

• 1987
  • 1987-02-10 WO PCT/AU1987/000036 patent/WO1987004654A1/fr not_active Ceased
  • 1987-02-10 EP EP19870901277 patent/EP0257064A4/fr not_active Withdrawn
  • 1987-02-11 ZA ZA870969A patent/ZA87969B/xx unknown

Non-Patent Citations (1)

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