US2356425A - Change-over device for circular weaving looms - Google Patents

Description

Aug. 22, 1944. H PE 2,356,425

CHANGE-OVER DEVICE FOR CIRCULAR WEAVING LOQMS Filed June 3 1940 2 Sheets-Sheet *1 Aug. 22, 1944. mm; v 2,356,425-

CHANGE-OVER DEVICE FOR CIRCULAR WEAVING LOOMS Filed June a, 1940 2 Sheets-She et 2 Patented Aug. 22, 1944 CHANGE-OVER DEVICE FOR CIRCULAR WEAVIN G LOOMS Henri P'elc, Flixecourt, France; vested in the Alien Property Custodian Application June 3, 1940, Serial No. 338,620 In France June 17, 1939 3 Claims.

Circular weaving looms exist of the type in which the warp threads are fed at right angles or approximately at right angles to the axis of the loom and the shuttles are pushed by rollers located outside the shed, acting, across a sheet of warp threads, on rollers mounted at the rear of the shuttles.

In order that this propulsion should be practically possible at high speed, the warp threads of the sheet trapped between the pushing roller and the pushed roller must be only slightly distorted, and for that purpose, it is necessary:

(1) That the pushing roller should rotate on itself in a direction and at a speed such that the sheet of threads which is clamped between both rollers is subjected to no tangential stress;

(2) That, at the place where it is clamped between the pushing roller and the pushed roller, said sheet of threads, should be inclined relative to the horizontal according to an angle equal or approximately equal to that which the tangent common to both rollers forms with the horizon.- tal, at their point of contact.

The second condition has already been satisfied by devices for forming the shed by means of needles, heddles or frames controlling only one warp thread, or a small number of warp threads, in such a manner that the distortion imparted to the threads by the passage of the rollers is sufliciently small so as not to damage the said threads. In the second case, the distance between the two extreme threads of one and the same frame can scarcely exceed, for the strongest threads, a small fraction of the diameter of the pushing roller.

Unfortunately these devices which lead to the use of a large number of needles, heddles or frames, necessarily of small dimensions, are costly, difficult to realise mechanically and do not allow of operating at high speed industrially.

The present invention is adapted to allow the use of frames each controlling a large number of threads (in particular, on a length greater than the diameter of the pushing roller) whilst forming, at the place where the sheet of warp threads is clamped between the pushing roller and the pushed roller, a perfect continuous curve thread to thread, having the desired inclination.

The change-over device according to the invention is more particularly characterised by the combination of means for controlling the heddle frames imparting to the latter vertical displacements ofsmall amplitude-,with a suitable shaping ofthe shuttle shoes such that the opening of the shed is accelerated by the sliding of said shoes against the warp threads and that the lower sheet forms, at the place where it is clamped between the pushing roller and the pushed roller, a continuous curve having the desired inclination regardless of the number of heddles in each frame.

For that purpose the shuttle shoes comprise a front nosearranged to engage in the slightly open shed and to complete the opening of said shed by the sliding movement of its edges on the upper and lower sheets.

But, in circular weaving looms which use, as members for clamping the weft, either combs sweeping over but a small portion of the shed, or pressure needles, or rollers, it frequently happens that owing to the breaking of a warp thread, the strand which has become free lies across the immediately adjacent warp threads. This is due to the displacement of the shuttles which tend to draw along after them any body which, for any reason whatever, becomes engaged thereon.

The entanglement resulting from this mishap can partly or entirely obstruct, in a certain zone, the passage of following or subsequent shuttles. The latter naturally cut the obstacles which are in their path. It will be easily understood that the defect produced becomes greater during the time it takes the shuttles to stop whe actuation of the loom is arrested to clearan entanglement.

The interlocked points of the entanglements are always in the axis of the sheds, and the defects produced increase in importance in proportion as said points, are removed from the well as the shuttles find it more and more difficult to clear their way. The attaching nose of their distorting shoe which acts in the same way as a cam, or as a plough share, cannot alone effect the selection of two interlocked sheets. In its displacement the shoe can only determine the breakages of most of the threads caught in the entanglement. Breakage caused in this manner results in repairs which are often long and, notwithstanding all the care taken, defects which can be frequently detected in the linen cloth.

The present invention is also adapted to remedy these inconveniences, or, at least to limit the seriousness thereof. For that purpose the point of the'distorting shoe of the shuttles is offset relatively to the median beating plane of the sheds. In this manner, if an entanglement is produced beyond a certain distance from the well, the two interlocked sheds are both picked up on the same side of the nose, and the weaving does not take place in the region considered.

Of course a slight defect is produced in the linen which will present, at certain places, missed picks, but this defect can be easily repaired. Moreover, numerous breakages of the warp threads are thereby avoided. The present invention is adapted for use with a warp protector and equalizing device such as described in my Patent No. 2,313,300, issued March 9, 1943; however, the use of this invention is not limited to said patented structure.

The accompanying drawings diagrammatically illustrates by way of example two embodiments of the subject-matter of the invention.

Fig. 1 is a perspective view of part of a circular loom showing a portion only of the central well through which the woven fabric descends, the rear of a shuttle and its pushing roller, the front of the following shuttle and two of the warp threads with the respective heddles.

Figs. 2, 3, 4 show the same elements at three successive moments of a change-over phas of the threads.

Fig. 5 illustrates a developed vertical section made according to the circumference described by the shuttles.

Fig. 6 is a view similar to Fig. 5 showing a shuttle of different shape provided in order to produce the complete uncovering of the shuttles by a backward movement of the latter.

Fig. 7 is a perspective view of a portion of a circular loom showing only one position of the central well through which the woven fabric descends, the rear of a shuttle slightly different from the above mentioned shuttles and its pushing roller, the front of the following shuttle and four of the warp threads with the respective heddles.

Fig. 8 is a view similar to Fig. 7 showing an entanglement caused by the breakage of a warp thread.

Fig. 9 is a developed vertical section made according to the circumference described by the shuttles of Figs. 7 and B.

l and 2 designate two warp threads controlled by two respective heddles a1 and 412 which are adapted to be moved in reverse directions by frames the vertical reciprocating stroke of which is only of small amplitude.

in and b2 designate two shuttles the shoe of which carries at the rear a roller 3 against which presses a pushing roller 4 having a continuous circular movement around the well 5.

The shoe of each shuttle terminates at the front in a nose 6 adapted to engage in the slightly open shed (Fig. 1) and to complete the opening thereof by the sliding movement of its edges on the upper and lower sheets (Fig. 2). It results therefrom that, even if each frame comprises a great number of heddles, the respective threads I or 2 form sheets the intersection of which by the vertical cylindrical surface over, which pass the shoes of the shuttles is a continuous curve, as shown in Fig. 5.

The profile of the rear nose 1 is so chosen that said curve, at the place where the lower sheet passes between the rollers 3 and 4, has the same be moved upwardly before the shuttles issue from the corresponding parts of the shed (Fig. 3) so that the threads, still pressed on the shoes, cross between the latter and the heddles until they are abandoned by the rear point of the shoes. Thus, the shed is prepared in which the nose 6 of the following shuttle (Fig. 4) is engaged. The cycle diagrammatically illustrated in Figs. 1 to 4 takes place over again in a similar manner every other shuttle.

This device allows, owing to the suitable shaping of the rear nose 1 the shoes, of obtaining automatic and complete uncovering of the shuttles by a simple backward movement of the latter according to a distance at least equal to their length. For that purpose, it sufiices that the point of said nose I should be above the lower parts' of the upper sheet of warp threads, as shown in Fig. 6. Upon the backward movement of the shuttles, all the threads I and 2 which are encountered are brought below the shoes so that the shuttles are entirely uncovered. For producing this backward movement, there is provided a second roller 8 at the front part of each shoe against which the pushing roller 4 will act.

In the foregoing it has been assumed that the heddle frames were arranged in pairs, for weaving linen, but it is to be understood that the device described can also apply to the use of any weaves. It suffices, instead of having two series of frames, to have a number 11. thereof greater than two and to suitably combine the eccentrics inclination as the tangent common to the latter.

Some of the heddle frames are adapted to be moved downwardly while others are adapted to and the cams which displace them. In this case, the cycle diagrammatically illustrated in Figs. 1 to 4 will take place over again similarly, every n shuttles.

According to the improvement illustrated in Figs. l'to 9, the front nose 6 of each shuttle is slightly offset relatively to the median beating plane of the sheds so that if an entanglement 1 due to a broken warp thread 8 occurs at a certain distance from the well 5 (Fig. 8), the two interlocked sheds will both be picked up below the nose 6 which will not risk breaking them.

I claim:

1. For use in a circular weaving loom of the type having heddle frames for producing a change-over movement of a small amplitude of warp threads and for dividing said threads into a shed of two superposed sheets, a shuttle having a separating cam the front and the rear of which are shaped to form noses having oblique inclines, the front nose of said separating cam being located at a short distance above the median beating plane of the sheds and the rear nose being located above the upper sheet of warp threads at the rear of the shuttle when the shuttle is in the shed. l

2. For use in circular weaving loom of the type having heddle framesfor producng a changeover movement of small amplitude of warp threads and for dividing saidthreads into a shed of two superposed sheets, a shuttle intended to pass between both sheets formed by said warp threads, a separating cam on said shuttle for spacing the warp threads apart and having at the front and at the rear a nose having oblique inclines, the rear nose of the separating cam of the shuttle being placed in such a manner that it is located above the .plane of the upper sheet of warp threads which are at the rear of the shuttle when the shuttle is in position in the shed. 1 i

3. In a circular weaving loom of the type havbelow the lower sheet at the rear of said loosely mounted roller and in contact with the loosely mounted roller, both of said rollers being positioned with respect to each other to have the lower oblique incline of the rear nose of said shoe lie in a plane which is tangent to both of said rollers at the contacting portions of said rollers,

HENRI PELCE.

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