The subject of the present invention is an improved blade device for seizing and holding stockings, especially for automatic stocking inverting machines.

It is known that stockings may be produced by a cycle which provides the production of a tube which is then sewn in correspondence with the toe, with the stocking inside out, that is to say from the side which will remain inside during the use of said stocking.

Also known in the art are machines adapted for automatically performing the inverting (turning inside out) of the stocking after said sewing has been effected, for the purpose of despatching the stocking to confectioning, already turned the right side out. Such machines are known, for example, from Patents Nos. 1 160 526 and 1 175 756 in the name of the present Applicant, in which there is provided a movable blade element, which is moved vertically downwards between pairs of rollers until it engages with the toe or "cap" of the stocking, which is then threaded and inverted on said blade element by said rollers, appropriately driven in rotation, and is then unthreaded off the blade by the action of other rollers, also driven in rotation, and is then despatched, already inverted, to the final confectioning.

During this cycle, which provides for the feed of the stocking by means of a pulling tongs unit from the stitcher and the subsequent closure of the rollers with simultaneous descent of the blade, it is, however, necessary to make the engagement of the tip of the blade with the toe of the stocking as certain and continuous as possible for the whole period of time necessary for the first pair of rollers to collect the stocking on the blade and commence the inversion, bearing in mind that failure to invert even a single stocking of the batch will require the subsequent manual performance both of the inversion and of the insertion of same into the group of which it is a member.

The technical problem therefore arises of creating an improved device which shall make it possible to achieve, at the instant of commencement of the inversion, a reliable and continuous coupling with the toe of the stocking to be inverted (turned inside out), which shall be easy and economical to construct and be suitable for incorporation into machines already in use, without a need for substantial modification of said machines.

Said results are achieved by the device according to this invention, in which the blade onto which the stocking to be inverted is threaded is constituted of an internally hollow tubular rod, having an upper opening placed in communication with appropriate suction means for the purpose of creating a vacuum inside said blade and having at least one opening at the lower end of the blade, by means of which said vacuum produces a suction action adapted for pulling and holding the toe of the stocking against the tip of the blade for a predetermined cycle time.

Further details will be obtained from the following description, with reference to the attached drawings, in which there are shown:

• in Figure 1: the blade element viewed in the direction of arrow A of Fig 2, with the end partially in section;
• in Figure 2: the blade element in section on the plane II-II of Fig. 1, and
• in Figure 3: a simplified schematic view of a machine for inverting stockings, with the device fitted.

As will be seen from the Figures, the device of the present invention, referenced generally 1, comprises a completely tubular blade having an upper part 2, closed at the top, and continued by a blade part 3, the lower end 3a of which has rounded corners 4 and an opening 5 disposed at the tip of the blade in the direction of the width of same.

Aproximately in the junction zone between the tubular part 2 and the blade part 3 there is fitted a portion of pipe 6, adapted to be connected to alternate suction devices, themselves known and indicated in the Figure simply by an arrow B.

In this way, as will be seen more easily seen from Figure 3, when said suction means are set in operation, the entire blade element is brought under sub-pressure with respect to the external environment, thus creating a true suction action at the opening 5 of the end 3a of the blade 3, which suction action draws the toe 8a of the stocking 8 towards the tip of the blade.

Said suction is synchronized with the instant at which the toe of the stocking is taken between the feed rollers 9 and 10 and the blade has been lowered until it comes into contact with, or very near to, said toe of the stocking.

The duration of suction is regulated according to the length of the stocking, or, essentially, for the time required for reliably starting the threading of the stocking to be inverted onto the end of the blade, holding it until the instant at which the counter-rotation of the rollers has performed the initial accumulation of the stocking on the blade for the purpose of inverting it. At this instant a sensor detects this accumulation and shuts of the suction, allowing the stocking to complete the inverting and discharge cycle.

The device according to this invention may also be used in the same machine, or in similar machines for promoting the discharge of the stocking, when already inverted and still threaded on the blade. In such a case it is possible to feed pressurized air into the tubular blade, so that this air, issuing at high speed from the opening 5, which may also be shaped to give a venturi effect, creates a blowing action adapted for removing the toe of the stocking from the blade and promoting engagement of the stocking between the rollers 9 and 10 for removal, or said stocking, already inverted, may be unthreaded off the blade and despatched for collection directly by the blowing of pressurized air without the intervention of the rollers.

It will be understood that many variants are possible of the shape of the hollow, tubular blade for exerting a suction and/or compression action on the toe of the stocking, and also that the means and duration of such actions may be varied, without thereby departing from the scope of the present invention.