EP0322576A1

EP0322576A1 - Method of releasing and mending wefts mispicked into the shed in jet weaving machines

Info

Publication number: EP0322576A1
Application number: EP88119879A
Authority: EP
Inventors: Jan Dipl.-Ing. Pajgrt; Vincenc Dipl.-Ing. Smeták; Jaroslav Dipl.-Ing. Kalina; Jiri Vystrcil; Michal Dipl.-Ing. Zemek; Milan Dipl.-Ing. Pus; Pavel Dipl.-Ing. Bucek
Original assignee: ZVS VYZKUMNEVYVOJOVY USTAV KONCERNOVA UCELOVA ORGANIZACE
Current assignee: ZVS VYZKUMNEVYVOJOVY USTAV KONCERNOVA UCELOVA ORGANIZACE
Priority date: 1987-12-29
Filing date: 1988-11-29
Publication date: 1989-07-05
Also published as: JPH01266240A; CS274515B1; CS1003387A1

Abstract

The purpose is an effective weaving process by automation in the case of mispicking a weft. This is achieved in such manner that the weft (1) is released in the shed (2) from the free part of length (7) in the form of an advancing wave (15) by action of a pressure fluid flow.

Description

The present invention relates to a method of releasing the mending wefts mispicked into the shed in jet weaving machines.
A method of releasing and simultaneous removing of mispicked wefts from the shed formed of warp threads is known. Upon stoppage of the weaving machine and its position with open shed for the mispicked weft, a clamp is slipped out to its free end by complex motion, performed by a pair of piston rods of pneumatic cylinders. The free weft end is gripped by the clamp whereupon, from the box fixed in front of the shed on the carrier of the shaped reed, a flexible belt is slipped out. At the end of the belt, a paddle with bent sides is mounted which is inserted into the shed below the clamp. On one side, the paddle is guided by the carrier and by its other bent side is gripped the weft held by the clamp. By the motion through the shed along the shaped reed, the mispicked weft gripped by the other side of the paddle is mechanically released fromt he interlacing point. Upon having passed through the whole shed length, the paddle is returned to the box by winding back the flexible belt. Thereupon, the clamp moves the gripped end of the released mispicked weft by swinging motion to the sucking nozzle which removes it from the shed by sucking-off. Upon finishing that splitting cycle, it is possible to restart the weaving cycle on the weaving machine.
The disadvantage of that method of releasing and removing the mispicked weft from the shed consists in an extraordinary technical requirement on the course of many releasing motions following exactly each other. The mechanical releasing is neither gentle nor reliable, as the weft to be released might break by overcoming its limiting stress, caused by encountering an unevenness of the weft by the blade, or another reason for overcoming its limiting stress. Thereafter, neither releasing nor removing of the weft can be completed any more.
The main subject matter of the method according to the present invention consists in that the weft is released from the free part of its length in the shed in the form of an advancing wave by action of a pressure fluid flow.
The advantage of the method according to the present invention consists in that the tensile component of the force exerted on the weft at the point of the wave is caused by the high-speed field of the pressure fluid.
A further substantial advantage of the present method consists in that upon releasing the mispicked weft, the same is also mended, thus making possible to omit the whole procedure of removing the weft by a following insertion of a new length.
The object of the present invention is represented in the accompanying drawings.

Fig. 1 represents, in axonometric projection, a part of the open shed with the throughpassing weft wave which is being released from the face of the fabric;
Figs. 2, 3, 4 and 5 represent the formation of the wave on a mispicked weft, together with the phased course of the wave through the shed width.

During the weaving process, the insertion of weft 1 through the shed 2, consisting of warp threads 3, in a known weaving machine is tracked and checked by the pick stop motion 4 at the end of said shed. Upon detecting a mispick of weft 1 towards the end of shed 2, pick stop motion 4 emits a signal to a not represented control mechanism which stops measuring the length of weft 1, and simultaneously prevents the inlet of pressure fluid into the inserting nozzle 5. At the same time, a signal is emitted for blockage of cutter 6, in order to prevent the separation of weft 1 at the inlet side of shed 2. During stoppage of the weaving process, a constant tensile stress is maintained on free part 7 of weft 1 for the purpose of preventing the breakage of the mispicked length 9 of weft 1 therefrom during the beat-up by reed 8. Upon stoppage of the weaving process, when the weaving machine is reversed to the shed 2 with the mispicked length 9 of weft 1, a part of the measured, retained following length 10 of weft 1 is released. The free part 7 of weft 1 between the measured following length 10 of weft 1 and the mispicked length 9 of weft 1 is then acted upon by a transversal pressure fluid flow from auxiliary nozzle 11. By action of the said transver sal pressure fluid flow, a loop 12 is formed on the free part 7 of weft 1 by releasing a part of the following length 10 of weft 1. This part of the method can be already performed during stoppage of the weaving process, thus eliminating the necessity of supplementary compensation of tension on the free part 7 of the uncut weft 1. Upon reversion to shed 2 with the mispicked length 9 of weft 1, the weaving machine is stopped in a position in which the insertion of weft 1 is started in a normal weaving process. This is advantageous for that reason that in this still first quadrant of the weaving machine revolution, the motion of warp threads 3 advances the motion from the interlacing point 13 moving reed 8 with the weft inserting channel. The consequence thereof is that the shed 2 of warp threads 3 is considerably opened while reed 8 is not too far from interlacing point 13 and the supplementary blowing nozzles 14 project into the shed 2 via the lower branch of warp threads 3 only with their upper parts with outlet openings.
By entry into the open shed 2 with the mispicked length 9 of weft 1 it is possible to start its actual releasing. By increased tensile stress caused in the free part 7 of weft 1 by the pressure fluid flow which acts upon loop 12, a part of the mispicked length 9 of weft 1 is released at the border of warp threads 3. This tensile stress can be formed in the free part 7 of weft 1 also by the action of other, e.g. mechanical means.
Thereafter, the pressure fluid entering the inserting nozzle 5 and the supplementary blowing nozzles 14 is released. Simultaneously, the pressure fluid flow from auxiliary nozzle 11 is suppressed. By tension of the weft inserting pressure fluid flow the released part of the following length 10 of weft 1 is transferred from loop 12 into shed 2, there forming on weft 1 a wave 15 of which the front 16 is being acted upon by a weft inserting pressure fluid flow discharged from the supplementary blowing nozzle 14.
The pressure fluid flow discharged from the supplementary blowing nozzles 14 thus must overcome the retaining frictional force of the mispicked length 9 of weft 1 in the wedge of shed 2 formed of warp threads 3. The intensity of that retaining force changes about the length of shed 2 because of the unequal tension of separate warp threads 3 and the unevenness of their fibres. Moreover, the length of wave 15 cannot be excessively increased as in that case a situation is brought about in which the connecting part 17 of weft 1 in wave 15, between its front 16 and the beaten-up mispicked length 9 is considerably acted upon by the preceding supplementary blowing nozzles 14. This causes a premature releasing of weft 1 from the interlacing point 13, a loosening of the connecting part 17 of weft 1 and, due to rotation of the pressure fluid flow, a twisting of the front part of the advancing wave 15 and a subsequent stoppage thereof. This, however, can be prevented by following up the movement of the front 16 of wave 15 in the shed 2 and by action of the pressure fluid weft inserting flow merely thereon.
The moving wave 15 passes then, about weft 1, the whole length of shed 2, the whole mispicked length 9 of weft 1 thus being released from the interlacing point 13 of the manufactured fabric 18. Simultaneously, the mending of the mispicked length 9 of weft 1 is performed as, by throughpassing of wave 15, weft 1 is stretched and straightened in shed 2. If, during weaving, a breakage of weft 1 in shed 2 happened, and a part of its length was blown off, said length being longer than the length added by the releasing wave 15, the pick stop motion 4 does not track the presence of weft 1 upon throughpassing of wave 15. In that case weft 1 is released from the measured following length 10 of weft 1 until the front 16 of weft 1 which is moved through shed 2 by the weft inserting fluid flow, arrives at the pick stop motion 4 which thereupon emits a signal by which the releasing from the following length 10 of weft 1 and the supply of the weft inserting pressure fluid flow is stopped. Thus, the mispicked length 10 is completely mended and the weaving cycle can be immediately carried on. When the woven material is of such type that defibering the impairment of weft 1 takes place during the throughpassing of releasing wave 15 by bending about a small radius on wave 15 or by excessive action of the pressure fluid thereupon, the mispicked, already released length 9 of weft 1 is removed from shed by withdrawing, e.g. by means of a known winding device, either towards the inserting, or the pick side of shed 2. When the released, mispicked length 9 of weft 1 is removed by drawing out to the pick side of shed 2, then a whole new following length 10 of weft 1 is simultaneously inserted into shed 2, and upon starting the normal weaving cycle, this length is already beaten up into the interlacing point 13 during the first revolution of the weaving machine. When weaving material tending to form starting streaks in the fabric 18, the weft 1 is cut-off upon releasing the mispicked length 9 by wave 15 and removed from the shed, e.g. in the manner already specified above. Upon removal of this mispicked length 9 of weft 1 the normal weaving procedure is restarted by insertion of the following length 10 of weft 1.

Claims

1. Method of releasing and mending wefts mispicked into the shed in jet weaving machines by a weft inserting pressure fluid flow in which after stopping the weaving procedure the measured and retained inserting length of the weft is permanently connected with its free part with the weft length mispicked in the open shed and beaten up in the interlacing point of the manufactured fabric, and the weft is released from the interlacing point from the inserting towards the pick side of the shed,
characterized in that
the weft (1) is released from the free part of length (7) in the shed (2), in the form of an advancing wave (15), by action of a pressure fluid flow.

2. Method as claimed in Claim 1,
characterized in that
before starting the releasing, a part of the retained measured following length (10) of weft (1) is released.

3. Method as claimed in Claims 1 and 2,
characterized in that
before starting the releasing of the mispicked length (9) of weft (1), its free part of length (7) is being acted upon by tensile stress.

4. Method as claimed in Claims 1 to 3,
characterized in that
by the pull of the released mispicked weft length, at least a part of the new following inserting length (10) of weft (1) is introduced into the shed.

5. Method as claimed in Claims 1 to 4,
characterized in that
the releasing pressure fluid flow acts upon weft (1) in at least one successive, continuous pressure wave.