Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Utility Patent
1998-12-03
2001-01-02
Ortiz, Angela (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C425S129200, C425S577000, C425S119000
Utility Patent
active
06168741
ABSTRACT:
This invention relates to footwear and particularly, although not exclusively, relates to a mould for making an article of footwear.
A known mould for the manufacture of plastics footwear by injection moulding is shown diagrammatically in
FIGS. 1 and 2
of the accompanying diagrammatic drawings wherein
FIG. 1
is a schematic vertical cross-section through a mould and
FIG. 2
is a schematic vertical cross-section through the mould rotated through 90° relative to FIG.
1
.
Known moulds are constructed of metal or other hard, rigid materials and generally comprise four or more principal components: two mould halves
2
,
4
to form a cavity of the mould; a last
6
centrally mounted within the cavity to form the core of the mould; and one or more sole plates
8
at the foot end of the mould beneath the last, to form the outsole of the article of footwear.
In order to keep the last
6
in a central position between the two mould halves
2
,
4
, so that both sides of an article of footwear manufactured using the mould are of equal thickness, the mould is constructed so that a considerable additional depth and thickness of material
10
is provided beyond the leg length
12
of the article of footwear to mechanically support the last
6
. The last is thereby supported from only one end by a cantilever effect; however, the parts necessary for this add considerably to the size, weight and cost of the mould and, furthermore, require precise fitting and machining. Additionally, such a mould must be used with an injection moulding machine with a large and powerful press or mechanical lock that can exert sufficient clamping pressure on the parts of the mould to maintain the parts in the desired positions.
Known injection moulding machines for footwear manufacture tend to be large, complex and expensive.
It is an object of the present invention to address problems associated with the manufacture of articles of footwear.
According to one aspect of the invention, there is provided an apparatus for manufacturing a complete article of waterproof footwear by moulding, said apparatus comprising a mould and a last means arranged in a cavity defined by the mould. Restrictor means is provided between the mould and the last means for supporting the last means and for restricting relative movement between the mould and the last means, said restrictor means comprising a male or female formation provided on or by the last means arranged to be engaged by the other of a male or female formation provided on or by the mould.
Preferably, the mould includes a first sole member used to form an inner sole of the article of footwear, the first sole member being interchangeable with a second sole member which is used to form an outer sole of the article of footwear and the restrictor means comprise a projection provided on the first sole member which engages with an opening in a sole part of the last means.
Alternatively, the restrictor means comprises a rod which is housed within the last means and extensible therefrom to engage with a hole provided in the mould.
Preferably, the last means includes a generally solid foot part and a generally hollow leg part which are releasably securable to one another. This enables the last means to be more easily removable from a moulded article of footwear.
The apparatus may further comprise a mould support and a multiplicity of moulds supported thereby, wherein said moulds are pivotable relative to the mould support so that the orientation of each mould can be adjusted.
According to another aspect of the invention there is provided a method for manufacturing a complete article of waterproof footwear by moulding from polyurethane, said method comprising, in a first moulding process, manufacturing a first footwear moulding with a hole therein using a mould which includes restrictor means provided between the mould and a last means for supporting the last means and for restricting relative movement between the mould and the last means, said restrictor means comprising a male or female formation provided on or by the last means arranged to be engaged by the other of a male or female formation provided on or by the mould, which restrictor means causes the production of said hole and in a second moulding process, covering or filling said hole.
Preferably, the hole is plugged with a plug member prior to the second moulding process.
In said first moulding process a first sole member may be used to produce an inner sole of the article of footwear and in said second moulding process a second sole member which is different to said first sole member may be used to produce an outer sole of the article of footwear.
Any suitable material or materials may be used in the method. Preferably, said material is flexible after curing. It may be a plastics material or the like, with polyurethane plastics material being especially preferred or it may be a rubber material or the like.
REFERENCES:
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patent: 4505660 (1985-03-01), Seidel et al.
patent: 4651444 (1987-03-01), Ours
patent: 4778368 (1988-10-01), Rebers et al.
patent: 5667738 (1997-09-01), Krajcir
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British Search Report for Application No. GB 9711495.3, dated Sep. 26, 1997 (1 page).
International Search Report for PCT/GB97/01504, dated Oct. 27, 1997 (2 pages).
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