1. Field of the Invention
The present invention relates to a working site to stitch manufactured items, of the type comprising a supporting frame defining at the top a supporting surface on which at least a sewing machine is disposed which is arranged to perform a given number of operations on a manufactured item being worked (or workpiece) and the front portion of which faces a user who is sitting in front of the supporting surface.
2. Prior Art
It is known that when the sewing of manufactured items such as garments and the like is concerned, many stitching operations of different types are requested. For example, on making a singlet or a vest it is necessary first of all to assemble and sew the different component parts thereof, then neck-bands or support tapes have to be applied to the neck edges and sometimes the sleeve edges; furthermore, when tapes are not intended to be applied, it is necessary to carry out hemmings at the lower ends of the singlet and the singlet sleeves.
In order to perform all operations necessary to manufacture a given item, the arrangement of a work chain formed of several consecutively aligned sites is provided in which each site is entrusted to a respective seamstress and substantially comprises a sewing machine adapted to execute a given working, which is mounted near a supporting table defined at the top of a supporting frame.
The number of sewing operations provided in a working cycle to obtain a finished item are brought to an end by a series of successive passages of the manufactured item from a work site to another. In greater detail, after the manufactured item has been submitted to a given working operation in a work site, it is delivered to the seamstress of the subsequent work site to be submitted to a new operation as provided by the working cycle.
However this working method has many drawbacks.
First of all, since the workpiece has to be transferred many times from a work site to another, there is an undesired increase in the handling time of the workpiece which adversely affects the productivity.
Many problems also arise from the fact that the work of each seamstress is, on one hand, subordinated to the productivity of all the other seamstresses which act upstream of said one seamstress--reference being made to the designed sequence for a working cycle--and, on the other hand, it exerts influence upon the work of the seamstresses acting downstream.
The above situation involves many difficulties in trying to reach the so-called "line-balancing", that is to ensure the graduate delivery to each seamstress of an amount of workpieces equal to the workpieces she is capable of sewing. In addition, not only said line-balancing is hardly achieved, but it can be easily impaired due to unexpected events such as for example the absence of a seamstress, the sewing machine breakdown and so on.
Furthermore each seamstress should also have a stock or supply of manufactured items to work at her disposal in order to prevent her from being devoid of said items when for any reason the seamstress coming before her temporarily stops or slackens production. Taking into account the number of working sites usually provided, the stocks reach a rather important amount and consequently involve an increase in the dwell time of each workpiece in the production line. In fact, it is always necessary to add the time during which a workpiece stays as a stock at each working site, to the time materially used to carry out the appropriate stitching operations on a workpiece.
For all the above reasons a quick delivery of the ordered items is adversely affected. In fact it is impossible to start the working of a specific type of manufactured item if the supply of all manufactured items previously in course of working has not been exhausted. It will be recognized that this drawback involves serious difficulties when works of great urgency are ordered.
Furthermore it is to be pointed out that the presence of a plurality of working sites involves a long idle time every time it is necessary to make all sewing machines ready to sew a new type of manufactured item, when the preceding working is over. This is a particularly troublesome inconvenience when small amounts of manufactured items of different types must be sewn.
The known art also suffers the disadvantage that it is very difficult to immediately detect possible manufacture defects on the individual items being worked. On the contrary it often happens that a manufacture defect due for example to a wrong setting of the sewing machine, the inexperience of a seamstress or the like, is detected in one of the sites following that in which said defect has been caused. In this case the detected defect is likely to be present in all garments of the stocks existing in all sites comprised between the one in which the defect has originated and the one in which it was detected.
It is also to be noted that the above described production systems do not stimulate the interest of the staff designed for said working as their task is almost limited to the systematic and repeated execution of a reduced number of operations. This aspect as well as being obviously important from a human point of view, also has repercussions on the productivity and quality of the finished product.
USPTO Backgrounds
USPTO Backgrounds