US3828828A

US3828828A - Guiding comb for picking the weft by a stream of gaseous pressure medium

Info

Publication number: US3828828A
Application number: US00227875A
Authority: US
Inventors: J Cernocky; M Riha; J Martinec
Original assignee: Zbrojovka Vsetin np
Current assignee: Zbrojovka Vsetin np
Priority date: 1970-10-02
Filing date: 1972-02-22
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13
Also published as: CS148939B1

Abstract

A guiding comb for shuttleless looms for picking the weft thread into the shed of the loom, having teeth which can be adjusted in two angular positions, in the first one where the picking openings of the teeth form a practically completely closed channel, and in a second one, where gaps are created between adjacent teeth, enabling their entrance into and removal from the system of warp threads forming the shed.

Description

States Patent 1191 Cernoeky et al.

1451 Aug. 13,1974

[ GUIDING COMB FOR PICKING THE WEFT BY A STREAM OF GASEOUS PRESSURE MEDIUM Inventors Jiri Cernocky; Miloslav Riha, both 1 of Rybniky; Josef Martinec, Luh, all

of Czechoslovakia Zbojovka Vsetin Narodni, Vsetin, Czechoslovakia Filed: Feb. 22, 1972 Appl. No.; 227,875

Assignee:

Foreign Application Priority Data Oct. 2, I970 Czechoslovakia 667870 US. Cl. 139/127 P Int. Cl D03d 47/30 Field of Search 139/127 R, 127 P, 188

llllll lllll References Cited UNITED STATES PATENTS. 3,124,167 3/1964 Strake 139/127 P 3,557,345 1/1971 Svaty etal 139/127 P 7 Primary Examiner-Henry S. Jaudon [5 7] ABSTRACT A guiding comb for shuttleless looms for picking the weft thread into the shed of the loom, having teeth which can be adjusted in two angular positions, in the first one where the picking openings of the teeth form a practically completely closed channel, and in a second one, where gaps are created between adjacent teeth, enabling their entrance into and removal from the system of warp threads forming the shed.

3 Claims, 5 Drawing Figures GUIDllNG COMB FOR PICKING THE WEFT BY A STREAM OF GASEOUS PRESSURE MEDIUM BACKGROUND OF THE DISCLOSURE The invention relates to a guiding comb for picking a weft thread into the shed of a loom by a stream of a gaseous medium, the comb being particularly suitable for air jet looms.

In looms, where the weft thread is picked into the shed by a stream of pressure air, this stream of pressure air has tovbe confined in order to be able to pick the weft thread throughout the whole width of the shed. The arrangement confining the stream of pressure air taking along the picked weft thread has to be designed so as to prevent to the utmost any stray losses of the gaseous medium in the course of its contact with the surrounding air and thus to maintain its speed required for picking the weft thread. This requirement is particularly important for looms having larger reed-widths, where the weft thread has to be picked for a larger distance from the mouth of the arrangement, performing the picking of the weft thread by a stream of a gaseous medium.

Guiding combs are therefore used atpresent, the individual teeth of which engage between warp threads of an open shed, said teeth having openings for guiding the air stream. This arrangement substantially complies I with the requirements of confining of the air stream and can be advantageously usedfor looms having smaller widths of the reed. A drawback is that gaps must be between the individual teeth in order to enable their penetration into the system of warp threads. in the course of passage of the air stream taking along the picked in weft, the pressure air escapes through these gaps into the ambient space and surrounding air is simultaneously sucked in. Both these circumstances cause a reduction of speed of the air streamand thus its capability to reliably pick the weft, particularly for looms having larger widths of the reed.

An arrangement is furthermore used, where the open shed is in the course of picking coveredin its whole length by special cover plates, which together withone side of the reed form a closed space of triangular cross section. The weft is introduced into this, triangular space from one side by pressure air and is sucked on at the other side by another additional device. The warp threads of the open shed are in this case in a closed space which represents a drawback of this arrangement. During the picking of the weft into the shed by pressure air, the warp threads start to vibrate and thus braking or retarding the streaming air. If a warp thread should become loosened under these conditions, the picked in weft can be caught and cause a defect in the fabric.

According to another arrangement the weft is introduced by means the weft ofa hollow needle engaging up to the center of the open shed, where it is taken over by a similar hollow needle entering the shed from the opposite side, by means of which the weft is gripped by being sucked on and brought across the other half of the shed. After the taking over of the weft by the second needle, both needles are removedfrom the open shed. This arrangement issomewhat complicated, can operate with reduced speed only, and a further drawback is that such a loom needs a substantially larger floor space. An arrangement for picking the weft into the shed by means of a stream of pressure air .is also known, where this stream of pressure air is rectified by a special trough and complemented by additional pressure air,'suppliedby jets situated at certain distances along the whole width of the-shed. These jets are designed and controlled so as to be able to penetrate in the course of picking into the system of warp threads and to confine by the produced air stream the weft in the trough. This method permits a relatively reliable picking in the weft; much air is, however, dissipated and such method requires large amounts'of air.

It is an object of this invention to provide a guiding comb picking through the weft, which operates reliably, which eliminates the danger of the weft being caught by loosened warp threads, which is economical in air consumption and which may be used for larger widths of the shed. The teeth of the guiding comb according to this invention can be considered as parts of a hollow body, for instance of a cylinder, cut along parallel planes inclined with respect to the longitudinal axis'of this hollow body at a chosen angle and having a chosen thickness. Each individual tooth is provided with a stem, the axis of which is perpendicular to the axis of the imaginary hollow body. The individual teeth are by means of their stems controlled by a device, operating to turn all teeth simultaneously to two operating positions. The fundamental operating position of the tooth corresponds with the angle of the inclined cut of the imaginary hollow body, in the second operating position the teeth are turned perpendicularly to the axis of the imaginary hollow body to a position parallel with the warp threads. By turning the teeth, gaps are produced between the individual teeth, the magnitude of which depends on the chosen angle of the cut, inclined with respect to the axis of the imaginary hollow body. With the teeth in this position it is possible to introduce them into the system of warp threads in the course of opening of the shed,.whereby the warp threads can pass through gaps between individual teeth of the guiding comb up to a moment where the teeth reach a position in front of the device for picking through the weft by means of a gaseous medium. At that time the teeth are again turned into their original fundamental position, forming by their openings a substantially fully closed channel, which efficiently confines the stream of gaseous pressure medium for picking in the weft. After the weft has been picked in, the individual teeth of the guiding comb are again turned into a position corresponding to the direction of warp threads and the teeth can be removed from the closing shed, whereby the picked weft, which has been in the picking openings of the teeth, is removed therefrom by way of exit slots provided in each tooth. The picked weft is after removal from the teeth beaten up to the fabric by the reed and woven in by exchange of both systems of warp threads. The internal walls of the picking openings of the teeth are after turning into their fundamental position, where they form a substantially completely dosed channel, substantially parallel with the axis of the channel, enabling a picking in of the weft from one or the other side of the shed.

An advantage of the thus arranged teeth of the guiding comb is that the gaseous medium causing the direct picking in the weft is efficiently rectified by the teeth and the speed of its passage is maintained with only small losses of its volume. The space required for the device confining the gaseous medium is small and the dimensions of the open shed may be also kept relatively small. A contact of the gaseous medium with the warp threads is impossible and no loosening and tearing up of these threads can be caused in the course of picking through the weft. The weft cannot be also caught by loose warp threads. The closed picking openings of the teeth form a tube with a smooth, non-converging, inside, enabling the weft to be picked alternately from one and then the other side of the shed.

DESCRIPTION OF DRAWINGS The attached drawings show an examplary embodiment of the arrangement of teeth of a guiding comb according to this invention, Where FIG. 1 shows an elevation of a tooth of a guiding comb in two operating positions A and B in the front and rear position of the batten,

FIG. 1a is a fragmentary view partially in section and partially in elevation showing means for transmitting the swinging movement of the crank to a linear reciprocatory movement of the rack which imparts a pivotal movement to the teeth between two active positions thereof;

FIG. 2 is a top view of the teeth in their fundamental position A,

FIG. 3 is a top view of the teeth, turned to position B, where gaps are created between the teeth, enabling DESCRIPTION OF PREFERRED EMBODIMENT The teeth 1 of the guiding comb are built substantially as parts of a hollow body, for instance of a cylinder, cut along parallel planes inclined with respect to the axis of this hollow body at an angle a and having a thickness s. (FIG. 2) Each tooth 1 has a stem 2, the axis of which is preferably perpendicular to the axis of the imaginary hollow body. The angular position of the teeth 1 is controlled by a mechanism 3 composed, for instance, of a rack guided within the batten 4 and of cams on the stems of the teeth, the whole arrangement being supported, for instance, on the batten 4 and controlled by a crank 5 (FIG. 1). The fundamental position A of the teeth 1 corresponds angularly to the angle a of the plane of the inclined cut of the imaginary hollow body (FIG. 2). In this position the teeth 1 of the guiding comb form a continuous substantially closed channel 6 for confining the stream of the gaseous medium in the course of picking the weft. At the moment prior to turning of the batten 4 with the reed 7 to the beating up position the teeth 1 are turned to position B (FIG. 3), creating gaps between the individual teeth 1, enabling the entrance of the teeth of the guiding comb through the system of warp threads into the shed, or their removal from the shed after the weft has been picked in.

The position B of the teeth 1 is advantageously parallel with the warp threads 8. Immediately after entrance of the teeth into the shed, in the course of which movement the teeth finish by their flanks the separation of warp threads, even of those which are loosened and are hanging over into the shed, an impulse is generated for turning the teeth to the fundamental position A creating a continuous closed channel 6, which confines the stream of gaseous medium taking along the weft after it has left the jet. After the weft has been picked in and after a corresponding impulse, the teeth 1 of the guiding comb are turned back to position B and the removal of the teeth 1 from the shed is started at a simultaneous removal of the picked in weft from the picking opening of the teeth by way of exit slots 9, which are preferably arranged so as to be in position B of the teeth 1 (FIG. 3) in register and in a common plane, parallel with the axis of picking of the weft in the shed. During a turn of the teeth 1 to position A the exit slots are mutually offset, so that the picking channel is closed and any slipping out of the weft from the channel in the course of the picking operation is prevented.

The embodiment shown herein operates in the following manner, reference being had specifically to FIGS. 1 and 1a. The swinging movement of the crank 5 is transmitted via a connecting rod 10 to a sword 11, the sword 11 being pivoted at 12 at one of its extremities and at the other extremity being fixedly attached to the batten 4. A cam 13, the outer end of the crank arm, is connected to the connecting rod 10 by a pivot pin 14 which is fixedly connected to the connected rod. Mounted on an extension of the pivot pin 14 is a cam 13 which thus partially rotates about its axis in synchronism with the swinging movement of the connecting rod 10. The cam 13 cooperates by means of a pin cam follower 15 with an arm 16 of a two-arm lever 17 pivoted at 18. The arm 16 is constantly urged counterclockwise (FIG. 1a) by a coil tension spring 19 secured to a lug 30 on the body 21 which is fixed to the batten 4. The second arm 22 of the two-arm lever 17 cooperates with the rack 23 which, due to its reciprocatory movement, imparts a pivotal movement to all the arms 24 projecting from the stems 2 of the respective teeth 1, also as shown in FIG. la.

We claim:

1. In a jet loom having a batten, and in which weft thread is picked by stream of a gaseous pressure medium through sheds formed in warp threads, the improvement which comprises a comb mounted on said batten for guiding a stream of gaseous pressure medium through successive sheds, the comb having teeth each of which is provided with a stem, means on the batten for pivotally supporting the stems of said teeth in alignment along the length of the batten, and means for synchronously turning all of the teeth about the axis of their stems from a first terminal position in which the teeth lie transverse to the length of the batten and present warp thread receiving slots therebetween thereby permitting their entrance into and their removal from the system of warp threads forming the sheds in a loom, to a second terminal position in which the interfaces between successive teeth lie at acute angles with respect to the length of the batten with adjacent interfaces being in substantial interengagement, whereby the teeth form an elongated substantially closed hollow body having a passage therethrough for the picking of the weft.

2. Guiding comb as set forth in claim 1, the teeht having openings therethrough, said openings in the second terminal position of the teeth lying coaxial, the internal walls of the openings of the teeth in said second terminal position forming a smooth and completely closed channel for picking the weft.

3. Guiding comb as seth forth in claim 1, wherein the circumference of each of said teeth is interrupted by an exit slot for the removal of the pick weft thread, said slot so located that in said first terminal position of the comb teeth said exit slots are in register, and in the second terminal position of the comb teeth said exit slots are offset.