Sewing – Stitch forming – Feeding work material
Patent
1995-02-28
1996-07-30
Izaguirre, Ismael
Sewing
Stitch forming
Feeding work material
112318, 112322, D05B 2710
Patent
active
055401643
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The invention relates to workpiece positioning apparatus whereby two workpiece portions can be positioned with selected regions thereof in a desired relationship, e.g. an overlapping relationship, and be progressively advanced, in said relationship, through an operating locality of a machine by which said selected regions are progressively treated, e.g. a sewing machine at the operating locality of which a reciprocable needle is located for effecting a progressive sewing operation along said regions, the apparatus comprising workpiece support means for supporting the workpiece portions, workpiece clamping means co-operable with the workpiece support means for clamping the workpiece portions in the desired overlapping relationship, and advancing means for advancing the workpiece portions, clamped as aforesaid in said relationship, along a desired path through said operating locality.
2. Background Art
It is advantageous in the manufacture of certain three-dimensional articles, e.g. shoe uppers, to sew the constituent workpiece portions of the article together in a manner that results in the formation of a three-dimensional construction. This manner of stitching, commonly known as "sprung stitching", is adopted because it imparts a preliminary shape to the sewn article which facilitates the ultimate shaping by stretching the article around a former, which in the case of shoe uppers would be a last.
Whereas in general the feeding of workpiece portions through the operating locality of a treatment machine, e.g. a sewing machine, is relatively straightforward when the portions are "in the flat", difficulties arise in the case of sprung stitching, essentially because the selected regions to be sewn together will each have a stitching region which, while corresponding to the desired stitching path along which the portions are to be sewn, is shaped such that it does not overlap the region of the other portion along the whole of its length when the workpiece portions are in a substantially flat condition.
The two stitching regions must of course overlap at the time they are presented to the needle in order to ensure that the workpiece portions are sewn accurately together along the desired stitching path. One known method of ensuring that the stitching regions are accurately aligned is to deform and temporarily secure the workpiece portions together as a pre-assembly prior to presentation to the needle. When thus secured in this deformed condition the workpiece portions can be sewn together along the desired stitching path without any further need for positional adjustment of either of them. This method is, however, time-consuming because the deforming and temporarily securing operation is essentially a manual one.
Alternatively, the workpiece portions may be advanced to the operating locality of the machine and the operator must ensure that they are progressively deformed to bring the regions into overlapping relationship as they are fed. In such a case, reliance is thus placed solely on the skill of the operator and the task is time-consuming and requires considerable and sustained concentration.
THE INVENTION
It is an object of the present invention to overcome the problems associated with the known methods of preparing two workpiece portions of the type referred to above for presentation to the operating locality of the treatment machine. This object is resolved in accordance with the present invention, in an apparatus as set out in the first paragraph above, in that, for enabling workpiece portions to be treated having selected regions which do not match one another along the whole of their length when the portions are in a substantially flat condition, the workpiece clamping means comprises two elements, one engageable with each of the workpiece portions, by each of which elements movement of the workpiece portion engaged thereby can be effected transversely of said path, while the portion remains clamped as aforesaid, thus to bring the regions progressively into the desired
REFERENCES:
patent: 4653414 (1987-03-01), Harrington
patent: 4825787 (1989-05-01), Babson et al.
patent: 5031552 (1991-07-01), Hansberry
patent: 5033399 (1981-07-01), Miyachi et al.
Gilbert James M.
Grantham John W.
Taylor Gaynor E.
Taylor Paul M.
British United Shoe Machinery Limited
Izaguirre Ismael
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