Textiles: spinning – twisting – and twining – Apparatus and processes – Splicing
Reexamination Certificate
1999-04-29
2001-03-13
Falik, Andy (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Splicing
C242S475400
Reexamination Certificate
active
06199360
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for pneumatic knotless splicing of threads or yarns, to be installed on textile machines, in particular on automatic spoolers.
The invention is based on a device of this type known from U.S. Pat. No. 5,680,751, or from the corresponding patent DE 196 10 818, from which known device the device according to the invention takes and maintains all the prerogatives and main characteristics, in particular those of permitting remote centralised regulation of the basic parameters of the splicing cycle, such as the duration both of the jet of compressed air used for preparation and pre-treatment of the ends of the thread or yarn to be joined, and of the jet of compressed air used in the splicing chamber, for execution of the knotless pneumatic splicing of the ends of the thread or yarn, and the length of overlapping of the prepared ends of the thread or yarn at the moment of splicing.
In the known device, the compressed air is admitted into the splicing chamber, and optionally also the compressed air is admitted into the units for preparation of the ends of the thread or yarn to be joined, by means of solenoid valves which can be controlled separately, remotely from the device, thus making the device to some extent dependent on other units of the textile machine on which the splicing device is installed.
The object of the present invention is mainly to eliminate this dependence of the splicing device on other units installed on the textile machine, thus making it independent from separate solenoid valves, which are remote from the points of use of the jets of compressed air.
For its actuation, like the known device, the splicing device according to the invention also comprises its own small, reversible electric stepper motor, which can be controlled remotely by electric pulses, in order to give rise to rotation in steps from a starting position, in a forward direction, and then, after a specific number of advance steps, to rotation in a direction of return, of a set of drum control cams, and of a cam in this set which controls the movement of the levers to draw the ends of the yarn or thread from the preparation units, in the direction of the splicing chamber, the said cam having a profile which increases progressively, and preferably in steps.
In order to achieve the above-described object of making the splicing device independent from separate units of the machine on which the device is installed, and in particular from a distinct, separate solenoid valve to control the intake of the jet of compressed air into the splicing chamber, according to the invention the device is provided with a slide valve which can be actuated by a specific cam in the set of drum cams, which cam is divided, for a limited section, into two parallel branches, the first in order to give rise, during rotation of the cam drum in the forward direction, to displacement of the rod of the slide valve in one direction, and the second, in order to give rise, during rotation of the cam drum in the direction of return, to displacement of the rod of the slide valve in the opposite direction, a specific amount of free play also being provided in the lever transmission, between the said cam with an increasing profile and the drawing levers, and the drawing levers being provided with braking means, in order to keep them stopped in the displaced position, on completion of the forward rotation of the cam drum.
SUMMARY OF THE INVENTION
In the device according to the invention, when the cam drum is rotated in the forward direction by the small stepper motor, by means of displacement of its rod in one direction, the slide valve controls the intake of the jet of compressed air into the units for preparation of the ends of the thread or yarn to be joined, and then, via the cam with an increasing profile, the drawing levers are displaced from their rest position, as far as the position which corresponds to the required overlapping of the prepared ends of the thread or yarn, after which the rotation in steps of the cam drum in the forward direction is stopped and inverted, whereas the drawing levers are kept stopped in the position reached, by the said braking means, and, during rotation of the cam drum in the return direction, by means of the second of the said two parallel branches, the rod of the slide valve is displaced in the opposite direction, and the valve controls intake of the jet of compressed air into the splicing chamber, for execution of the knotless splicing of the two ends of thread or yarn. It should be pointed out that unlike in the known device on which the present invention is based, in the present case, on completion of its advance in steps in the forward direction, and before it begins the rotation in the return direction, the rotation of the small electric motor is not stopped, such that the cam with a progressively increasing profile can keep the return levers for the prepared ends of the thread or yarn in the displacement position reached, since the rod of the slide valve must immediately begin its return displacement, such that the valve can control the intake of the jet of compressed air into the splicing chamber, and a separate solenoid valve is no longer provided for this purpose.
It is for this reason that in the device according to the invention, the return levers must be provided with braking means, in order to allow them to remain in the displaced position reached, and also, in the lever transmission between the cam with an increasing profile and the drawing levers themselves, a specific amount of free play must be provided, in order to allow the cam with an increasing profile to carry out its return movement to the starting position, without also immediately dragging with it the drawing levers also. This free play is eliminated only on completion of rotation of the cam drum, when the movement of the drum is inverted.
Simply by means of remote control by electrical pulses transmitted to the small, reversible electric stepper motor, the device according to the invention makes it possible to carry out three types of regulation, i.e.: by stopping the small electric motor at the moment when the rod of the slide valve is in the position which permits intake of the compressed air into the units for preparation of the ends of the thread or yarn, it is possible to regulate the duration of this jet of compressed air, and thus the efficiency of the preparation of the ends of the thread or yarn; by stopping the small electric motor again during its return rotation, at the moment when the rod of the slide valve is in the position in which it opens the intake of the jet of compressed air into the splicing chamber, throughout the stoppage time it is possible to regulate the duration of the jet of compressed air in the splicing chamber, and thus the efficiency of knotless pneumatic splicing; finally, by determining the steps of advance in the forward direction, and the moment of inversion of the rotation of the small electric motor, it is possible to establish the position of displacement reached by the drawing levers, and thus the required overlapping of the prepared ends of the thread or yarn in the splicing chamber during execution of the pneumatic splicing.
By providing a slide valve inside the splicing device, it has also been possible to allocate to this valve an additional task which has not hitherto been carried out pneumatically in the known devices, i.e. of controlling closure of the cover of the splicing chamber. In fact, hitherto, this control has always been carried out purely mechanically, by means of a cam of the cam drum, and corresponding lever transmission.
Positioning the slide valve in the device in the immediate vicinity of the units which use the compressed air, also has the advantage of avoiding dead time caused by the path of the compressed air, from the point at which the supply is opened up and released (for example separate, remote solenoid valve), to the point at which it is used (for example splicing chamber). In add
Falik Andy
Mesdan S.p.A.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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