Classifications

• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
  • A43B23/00—Uppers; Boot legs; Stiffeners; Other single parts of footwear
  • A43B23/08—Heel stiffeners; Toe stiffeners
  • A43B23/081—Toe stiffeners
  • A43B23/082—Toe stiffeners made of metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D18/00—Pressure casting; Vacuum casting
  • B22D18/02—Pressure casting making use of mechanical pressure devices, e.g. cast-forging
• • A—HUMAN NECESSITIES
  • A43—FOOTWEAR
  • A43D—MACHINES, TOOLS, EQUIPMENT OR METHODS FOR MANUFACTURING OR REPAIRING FOOTWEAR
  • A43D2200/00—Machines or methods characterised by special features

Definitions

• the present invention relates to an apparatus for manufacturing toe caps, for safety shoes and the like, made of aluminum, aluminum alloys and light alloys in general, and to the method of manufacturing toe caps.
• toe caps currently used in safety shoes or working shoes are usually made of steel and have a substantially constant thickness, since they are mostly manufactured by pressing metal plate.
• the aim of the present invention is to eliminate the drawbacks noted above, by providing an apparatus for producing toe caps for safety shoes made of aluminum, aluminum alloys and light alloys in general that allows to obtain a toe cap capable of withstanding impact tests and is considerably lighter than corresponding steel toe caps.
• an object of the invention is to provide a toe cap whose internal structure is practically free from gas with particularly closely arranged molecules, so as to achieve high mechanical strength properties.
• Another object of the present invention is to provide an apparatus that allows to form the part and in practice to forge it in the plastic state without sprue.
• Another object of the present invention is to provide an apparatus that allows to obtain a toe cap which, in addition to being nonmagnetic and lightweight, has a low cost.
• an apparatus for producing toe caps for safety shoes and the like made of aluminum, aluminum alloys and light alloys in general, according to the invention, which comprises a bottom die and a top die which can be associated with respective platens and can be mated so as to form at least one impression, characterized in that it comprises at least one male plug that can be inserted in said impression in order to form the shape of the part being formed and is suitable to act as a flow control element for the duct for introducing the liquid metal in said impression.
• Figure 1 is a schematic view of the apparatus according to the invention, with the dies in the open position;
• Figure 2 is a view of the apparatus with the dies closed during the step for introducing the liquid metal
• Figure 3 is a view of the apparatus during formation of the part by descent of the male plug
• Figure 4 is a view of the apparatus during the step of extracting the part from the bottom die;
• Figure 5 is a view of the apparatus during separation of the part from the male plug;
• Figure 6 is a schematic view of the resulting part. Ways of carrying out the Invention
• the apparatus for manufacturing toe caps for safety shoes and the like made of aluminum, aluminum alloys and light alloys in general, according to the invention, comprises a bottom die 1 and a top die 2, which are respectively associable with a lower platen 3 and with an upper platen 4.
• the dies can be mutually mated, by way of the relative motion of the platens and preferably by way of the descent of the upper platen, so as to form an impression 5.
• the particularity of the invention consists in that at the impression 5 there is a duct for introducing the liquid metal 10, which is connected to an assembly for feeding the molten metal 11, which is temperature-controlled and allows to introduce in the impression 5 pre-dosed quantities of liquid aluminum or aluminum alloys.
• a male plug 20 which is associated with a movable part 21 of the upper platen 4 constituting motion means for the male plug able to provide, after the introduction of the molten metal inside the impression 5, the introduction of the male plug forming the exact shape of the part being manufactured; further, the male plug 20 achieves the closure of the inflow duct 10 by means of a flat portion 22 that closes the passage of the duct 10 and allows to form a sprueless part.
• the male plug 20 defines in practice a flow control element for the duct
• the bottom die 1 is provided with lower heating resistors 30 and correspondingly the top die 2 is provided with upper heating resistors 31, which allow optimum temperature control, together with the presence of thermocouples 35 that perform temperature control of the male plug 20, wherein appropriate heating resistors are provided.
• the difference between the temperature of the metal before formation and the temperature of the dies that form the impression is preferably as low as possible and is between 150 and 250 °C, preferably 200 °C.
• the dies are heated to a preset temperature by means of the electric resistors 30 and 31, and the metal in the furnace is brought to the required temperature.
• the upper movable platen descends rapidly until the bottom die and the top die are mutually closed, keeping the male plug 20 partially extracted from the impression 5.
• the dosage system for the liquid metal constituted by aluminum and aluminum alloys, is activated in order to introduce a quantity of dosed liquid metal in the impression 5 by means of the inflow duct 10.
• the descent of the male plug 20 is activated, under the actuation of the cylinder 21, which performs a descent at a preset speed and applies a preset pressure. It is considerably important that the descent of the piston 20 automatically also closes the inflow duct 10 for the liquid metal.
• the solidification time begins; during this time, the pressure rises according to a preset criterion in order to forge the part, designated by the reference letter P, which is still in the plastic state.
• the ejector piston 41 is actuated and acts on the ejector 40 with an upward motion at a preset speed, simultaneously with the actuation for the rise of the upper platen of the press, male plug 20, up to a preset level. Once the preset upper level of the upper platen has been reached, the rise of the male plug 20 is actuated, consequently releasing the resulting part.
• the thicknesses of the resulting part can vary from point to point according to the requirements of mechanical strength of the part, a feature that was not obtainable with conventional methods, which instead started from the pressing of a plate.
• the materials used, as well as the contingent shapes and dimensions may be any according to requirements.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
• Forging (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (2)

Family

ID=11447619

Family Applications (1)

Country Status (14)

Cited By (3)

Families Citing this family (4)

Family Cites Families (9)

• 2001
  • 2001-05-09 IT IT2001MI000949A patent/ITMI20010949A1/it unknown
• 2002
  • 2002-05-02 CA CA002446373A patent/CA2446373A1/en not_active Abandoned
  • 2002-05-02 CZ CZ20033058A patent/CZ20033058A3/cs unknown
  • 2002-05-02 BR BR0205351-9A patent/BR0205351A/pt not_active IP Right Cessation
  • 2002-05-02 RU RU2003135641/12A patent/RU2003135641A/ru not_active Application Discontinuation
  • 2002-05-02 EP EP02750875A patent/EP1385399A2/en not_active Withdrawn
  • 2002-05-02 SI SI200220016A patent/SI21343A/sl not_active IP Right Cessation
  • 2002-05-02 US US10/477,094 patent/US20040154779A1/en not_active Abandoned
  • 2002-05-02 WO PCT/EP2002/004812 patent/WO2002089625A2/en not_active Application Discontinuation
  • 2002-05-02 SK SK1455-2003A patent/SK14552003A3/sk unknown
  • 2002-05-02 PL PL02366992A patent/PL366992A1/xx not_active Application Discontinuation
• 2003
  • 2003-07-08 TN TNPCT/EP2002/004812A patent/TNSN03111A1/en unknown
  • 2003-11-03 MA MA27380A patent/MA26175A1/fr unknown
  • 2003-11-03 ZA ZA200308566A patent/ZA200308566B/en unknown

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