Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
  • A01B1/00—Hand tools
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
  • A01B1/00—Hand tools
  • A01B1/02—Spades; Shovels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25G—HANDLES FOR HAND IMPLEMENTS
  • B25G3/00—Attaching handles to the implements
  • B25G3/34—Attaching handles to the implements by pressing the handle on the implements; using cement or molten metal, e.g. casting, moulding, by welding or the like

Definitions

• the invention concerns a tool and a method for the manufacture of the tool.
• the shaft also comprises a metal tube, which, in the area between the handle and the tool part, comprises at least one bend and is surrounded by a plastic material of the same composition as the handle and tool part, and where assemblies respectively between the shaft and the plastic material surrounding the metal tube, and between the tool part and the plastic material surrounding the metal tube constitute a tight fusing together of plastic materials of the same composition as the remainder.
• the tool configured in this manner is thus especially hygienic with regard to its surfaces, in that the whole surface is enveloped in the same plastic material, and in that the plastic material selected is one which is acceptable within the relevant industry. All assembly transitions will be tight. Moreover, as a consequence of the shaft being provided with at least one curvature, an ergonomic shape is achieved, while at the same time that the necessary stiffness is retained, in that the tube is made of a suitable metal which ensures that regardless of almost any product for which the tool is used, the tool will not be subject to any deflection.
• the possibility is achieved of being able to mould the shaft of the tool with an ergonomically correct shape and also to adapt the product individually, in that the inner plastic material ensures that the metal tube does not become flat or get fractured during the moulding. Since the shape of the tool thus becomes independent of the mould, it is inexpensive to effect adjustments in the design.
• the invention also concerns a method for the manufacture of a tool, characterized in that
• the shaft is straight before mounting of the handle and tool part
• the tool is secured in the tool part and the handle, and
• the shaft is rotated to create friction welding between the shaft's surrounding plastic material and the handle and tool part respectively.
• figs. 1a-c show a shovel according to the invention seen from the front, from the side and in perspective
• fig. 2 shows a section along the line ll-ll in fig. 1 .
• figs. 3a-b show a fork according to the invention seen from the front and in perspective.
• Fig. 1 shows an example embodiment of a tool according to the invention, here a shovel
• the tool 1 comprises a shaft 2 with a handle 3 mounted on its one end and a working part, here a shovel blade 4, mounted on its opposite end.
• the handle 3 and the blade 4 are made of the same plastic material, preferably polypropylene, in that this is a weldable material.
• the shaft itself consists of a so-called sandwich construction, and consists in- nermost of a round rod 9 of polypropylene, said round rod being enclosed within an aluminium tube 8, which in turn is surrounded externally by a polypropylene tube 7. It is important that the shaft's outer plastic material consists of the same plastic material as the handle and tool part, thus making it possible to create a tight joint between these parts where a fric- tion weld is selected.
• Fig. 2 shows a section through the shaft and the mutual relationship between the individual parts, and as mentioned above said shaft consisting innermost of a solid round rod of polypropylene 9 surrounded by the alu- minium tube 8, which in turn is surrounded by a tube of plastic material, i.e. polypropylene 7.
• a suitable dimension for the tube part can be that the inner round rod is 20 mm in diameter.
• the aluminium tube itself has an inside diameter in the order of 20 mm and an outside diameter of 25 mm, while the outer polypropylene tube has an inside diameter of 25 mm and an outside diameter in the order of 27-28 mm.
• Aluminium is chosen for the reason that this metal will give the tool a stiff shaft, and that the strength of the aluminium and its alloys is sufficiently great for use for the shovel function, while at the same time that aluminium is a light material. Since aluminium is not approved within the foodstuffs industry, it is given the outer covering of plastic as described above.
• the reason for providing a solid round rod of plastic material inside the tube is that the shaft, after the shovel has been assembled, shall be shaped in an expedient ergonomic design, and whereby the shaft is preferably provided with an upper and a lower bend 12 with an angle in the order of 5-15°. This is shown in fig. 1 b, where the shovel is seen from the side.
• the shaft can naturally be provided with several bends depending entirely on require- ments and the user's specific demands.
• the aluminium tube can be replaced by stainless steel of smaller wall thickness.
• the outer polypropylene tube 7 on the aluminium tube 8 does not cover the whole of the aluminium tube, in that about 75 mm at each end lies free and is thus not surrounded by the plastic, whereby the bare surface of the alu- minium tube protrudes.
• the connection part of the handle 3 comprises a tube with an inner diameter of a dimension which enables it to be press- fitted down in the shaft, and corresponding conditions apply at the other end, where the shovel part has a connection part 11 with dimensions which similarly allow press-fitting on the aluminium tube.
• connection parts 10, 11 are such that a smooth surface transition arises between these parts and the outer polypropylene tube 7 on the shaft 2.
• Fig. 1c shows the shovel seen in perspective, and also shows the ergo- nomically correct shape of the shovel.
• the actual manufacture of the shovel is effected by inserting a solid round rod of polypropylene inside an aluminium tube of suitable length, so that the rod fills out the inner cavity of the aluminium tube.
• the outer polypropylene tube 7 is then pushed down over the aluminium, and in such a manner that approx. 75 mm of the tube at each end is exposed.
• the handle with its connection part 10 is now pressed down on the one end of the exposed aluminium tube, and the tool part, here a shovel blade with its connection part 11 , is pushed down on the other end of the shaft.
• the tool must now be set up, and here it is important that the shaft itself is completely straight.
• the handle 3 and the shovel blade 4 are now held fast, in that opposing pressures are applied from each end, and the shaft is now brought to rotate at a speed in the order of 900 rpm. With this rotation, a friction welding is effected between the handle's polypropylene and the shaft's 2 outer polypropylene tube 7, and a corresponding welding at the opposite end between the lower connection part 11 of the shovel blade 4 and the abutting polypropylene tube 7 which lies around the tube 8.
• the friction welding results in a completely tight fusion between the two assembly points 5, 6, and also ensures that these assembly points become smooth, which means that there is no basis for bacterial growth.
• the shovel or tool 1 is now taken down and transferred to a work station where the shaft is provided with the necessary bends 12.
• solid plastic material for example polypropylene
• This bending and thus also shaping of the finished tool can be industrialised so that it is the same identical shovel or tool which emerges from the work station.
• it can also be individualised in a very simple manner, unlike the known shovels where changes in the finished product necessitate a total change of the mould itself.
• the points of assembly can possibly be given a subsequent surface finishing for the removal of any flash or fraze.
• the relevant method provides a product which has a very hygienic surface
• the product is completely covered with plastic and with a smooth surface, which is a surface which is accepted within the foodstuffs industry
• a very high speed of production in order for the friction welding to take place, it is an important parameter firstly that an interference fit is effected between the connection parts and the shaft itself, and secondly that the shaft and the connection parts are circular in cross-section.
• the plastic materials which abut against each other are of the same type, hereby making a friction welding possible and enabling an optimum fusing together to be achieved.
• the invention can not only be used for shovels, but naturally also for other products where demands are made regarding great stiffness and lightness combined with a smooth surface and with due consideration to an ergo- nomic shape.
• a tool i.e. a fork
• a tool which similarly comprises a shaft 2, a handle part 3 and a tool part 4, here in the form of a fork part.
• Other tools can also fall within the scope of the invention, e.g. spades, brooms, stirrers, dustpans etc.
• the handles and work parts can with advantage be injection moulded, and especially the handles will typically be the same regardless of which type of tool is involved, while the tool part can naturally be of various configurations.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Soil Sciences (AREA)
• Environmental Sciences (AREA)
• Food-Manufacturing Devices (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8099093

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Family Cites Families (3)

• 1997
  • 1997-08-12 DK DK92697A patent/DK92697A/da not_active IP Right Cessation
• 1998
  • 1998-08-10 AU AU86230/98A patent/AU8623098A/en not_active Abandoned
  • 1998-08-10 EP EP98937418A patent/EP1011303A1/en not_active Withdrawn
  • 1998-08-10 WO PCT/DK1998/000347 patent/WO1999009800A1/en not_active Application Discontinuation
• 2000
  • 2000-02-02 NO NO20000547A patent/NO20000547L/no not_active Application Discontinuation

Non-Patent Citations (1)

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