Weft cutter for air loom

Abstract: Weft cutter for air loom in which the mobile blade (15) is hinged onto the ram (18) of a pneumatic cylinder (19), which is pneumatically fed through a solenoid valve (22) provided, at its inlet, with a pressure regulator (25), with said ram (18) being kept in its resting position by a return spring (20) and said solenoid valve (22) being directly piloted from the loom control console (24).

Description: The present invention relates to a weft cutter device for air loom, which weft cutter, while is cheap, compact, operationally reliable and structurally simple, makes it possible the cutting times to be promptly and directly controlled as a function of the weaving conditions and, above all, the cutting operation to be disabled at will, even while the loom is being operating. It is well-known that in an air weaving loom the weft thread, drawn from a cop external to the loom, is entered into the open shed formed by the warp threads, from a plurality of nozzles and only after that said warp threads have reversed the shed by mutually exchanging their position, so as to lock the inserted weft thread between them, said weft thread is cut by the weft cutting device, so as to disengage it from said cop. According to the prior art, for instance in US-A-4,531,555 or EP-A-0 284 766, the used weft cutter is substantially constituted by a stationary blade with which a mobile blade cooperates, by being caused to oscillate by a mechanical drive means of cam type. Unfortunately, besides not allowing a direct and fast selection of the cutting times without having to act on in the loom -- beacuse such a selection would require that a manual action is performed inside the interior of the loom in order to disengage the fastening means of said cam onto its own shaft in order to suitably rotate said cam by a certain angle and finally to engage again said lock system -- such a device known from the prior art does not even allow the cutting operation to be disabled during loom operation. In order to obviate said drawbacks, said oscillation of the mobile cam was accomplished by means of an electro-mechanical drive unit in which a stepper motor drives the motion of the mobile blade through a suitable kinematic link means, or an electromagnetic drive means in which the mobile blade is driven by the action of an electromagnet. In fact, in these cases, the possibility is evident of selecting the cutting times and of disabling said cutting action at will, by suitably offsetting in time, or completely removing the motor or electromagnet biasing command. However, this latter type of weft cutters known from the prior art are affected by structural complexities which cause them to be rather expensive. In US-A-3,807,270 a cutting device for processing a thread on a spin-draw-winding machine, is disclosed. The purpose of the present invention is therefore of providing a weft cutter device which, with a simple, cheap, compact and operationally reliable structure makes it possible the cutting times to be promptly and directly controlled as a function of the weaving conditions and, above all, the cutting operation to be disabled at will, even while the loom is being operating. The above purpose is substantially achieved by directly driving the mobile blade by means of a pneumatic cylinder. In fact, it is evident that with such a structure, it is enough that the attending operator directly intervenes, from the air loom control console, on a solenoid valve in order to schedule at will the intervention times of said cylinder and consequently the cutting times, as well as the to disable said cutting action; on the other hand, with a simple pressure regulator installed at the inlet of said solenoid valve, it is also easily possible to vary the drive pressure fed to said pneumatic cylinder, and, consequently, the cutting force, as a function of the type of weft to be cut. From the above, one will furthermore easily realize the extreme structural and functional simplicity of the device -- and, consequently, its cheapness. Summing-up, the weft cutter for an air loom having a loom console, comprising a stationary blade cooperating with a mobile blade which is caused to oscillate by a drive system, from a resting position to an active position, and vice-versa, is characterized according to the present invention in that said drive system is constituted by a pneumatic cylinder the ram of which is hinged to said mobile blade and is urged to return back to its resting position by a return spring, which tends to keep said mobile blade in its resting position, said cylinder being pneumatically fed through a solenoid valve which is controlled from the loom console and is provided with a pressure regulator at its inlet. The present invention is better explained in the following by referring to the accompanying drawings, which illustrate a preferred embodiment supplied for merely exemplifying, non-limitative purpose, because technical or structural modifications can be supplied to it without departing from the scope of the present invention. On the other hand, it is clear that, although the weft cutter was disclosed up to here with regard to cutting the weft inserted in the air loom, it can also be used whenever in the loom the cutting action must be disabled during one or more operating step(s) of the same loom, such as, e.g., in the case of fals selvedge cutting, which may be carried out every two or more loom reed strokes, with consequent air saving. In said drawings: Figure 1 schematically shows a perspective view of an air weaving loom using the weft cutting device according to the present invention; Figure 2 shows a partially sectional side view, displayed on a strongly enlarged scale, of the weft cutter device of Figure 1. Referring to the above Figures, with (1) the external cop to the air loom is displayed from which the weft thread (2) is taken which, by running through the main nozzle (3), is entered into the open shed (4) formed by the warp threads (5) and (6), from a plurality of nozzles (7) and is then caught by the sucker (8). After that the reed (9) has beaten the inserted fill end (2) against the longitudinal edge of the fabric (10) under way of formation, and the warp threads (5) and (6) have exchanged their mutual position thus locking said fill end (2) in position between them, said fill end is cut at (11), close to the fabric (10) under way of formation, by the weft cutter (12) of the present invention. Said weft cutter (12) comprises a stationary blade (13) which, by being irremovably fastened onto the stationary body (14) of the loom, cooperates with a mobile blade (15) which which is hinged at its middle point, in (16), onto the stationary blade (13) and, at its free end (15'), is hinged, in its turn, onto the stem (17) of the ram (18) of a pneumatic cylinder (19). Said ram (18) is then urged downwards by a return spring (20), thus tending to keep said mobile blade (15) in its resting position, i.e., with its cutting edge (15") being spaced apart from the cutting edge (13") of the stationary blade (13), as illustrated in Figure 2. Finally, said pneumatic cylinder (19) is fed by the air source, not depicted in the Figure, through the duct (21) through a solenoid valve (22) which is electrically piloted, through the wire (23), directly from the loom control console (24) and is provided, at its inlet, with a pressure regulator (25). The operating way of the device is by now evident. After adjusting the operating pressure at the desired value by means of the pressure regulator (25), the mobile blade (15) will perform its cutting operation every time from the console (24) the solenoid valve (22) opening command is sent; when said command is not sent, the return spring (20) will keep the mobile blade (15) in its resting position.

Claims: Weft cutter (12) for an air loom having a loom console comprising a stationary blade (13) cooperating with a mobile blade (15) which is caused to oscillate by a drive system, from a resting position to an active position, and vice-versa, characterized in that said drive system is constituted by a pneumatic cylinder (19) the ram (18) of which is hinged to said mobile blade (15) and is urged to return back to its resting position by a return spring (20) which tends to keep said mobile blade (15) in its resting position, said cylinder being pneumatically fed through a solenoid valve (22) which is controlled from the loom console (24) and is provided with a pressure regulator (25) at its inlet side.

Inventors: CAPITANIO ROBERTO, SORA GIANLUIGI, ZANROSSO MAURO, CAPITANIO, ROBERTO, SORA, GIANLUIGI, ZANROSSO, MAURO
Applicants: NUOVO PIGNONE SPA, NUOVO PIGNONE S.P.A.
Application year: 1995
Main classification: D03D47
IPC codes: D03D47, D03D49