US3688807A

US3688807A - Weft drawing gripper for looms

Info

Publication number: US3688807A
Application number: US33286A
Authority: US
Inventors: Andrea Parolini
Original assignee: SOMET Societa Meccanica Tessile SpA
Current assignee: Promatech SpA
Priority date: 1969-04-30
Filing date: 1970-04-30
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: CA918541A; ES186800Y; GB1314086A; NL167739C; CH502460A; NL167739B; DE2020879A1; NL7006303A; FR2040443A1; ES186800U; BE749719A; DE2020879B2

Abstract

In a continuous weft supply loom wherein a pair of reciprocating weft-carrying grippers-one feeding and one drawing gripper-insert the weft in the warp shed, exchanging weft yarns at the center of the shed, the drawing gripper has a branch with a small raised end portion engaged by an oscillating arm for locking the weft, and a thin metal covering is applied to the surface of said raised end portion of the branch, said covering extending in the shape of a cantilever lamina for a short length along and above the non-raised portion of the branch.

Description

United States Patent Parolini 1 Sept. 5, 1972 [54] WEFT DRAWING GRIPPER FOR LOOMS [72] Inventor: Andrea Parolini, Gandino, Italy [73] Assignee: Somet Societa Meecanica Tessile S.p.A., Gazzaniga (Bergamo), Italy [22] Filed: April 30, 1970 [21] Appl. No.: 33,286

[30] Foreign Application Priority Data April 30, 1969 Italy ..16262 A/69 [52] US. Cl. ..139/122 N [51] Int. Cl. ..D03d 47/20 [58] Field of Search ..139/l22, 122 N, 123, 127

[56] References Cited UNITED STATES PATENTS Wasylewiez ..139/122 N 2,813,548 11/1957 Dewas 139/123 3,390,707 7/ 1968 Scherillo ..139/l22 N FOREIGN PATENTS OR APPLICATIONS 482,852 12/1969 Switzerland ..139/ 122 N Primary Examiner-Henry S. Jaudon Attorney-Young & Thompson ABSTRACT In a continuous weft supply loom wherein a pair of reciprocating weft-carrying grippers-one feeding and one drawing gripper-insert the weft in the warp shed, exchanging weft yarns at the center of the shed, the drawing gripper has a branch with a small raised end portion engaged by an oscillating arm for locking the weft, and a thin metal covering is applied to the surface of said raised end portion of the branch, said covering extending in the shape of a cantilever lamina for a short length along and above the non-raised portion of the branch.

5 Claims, 4 Drawing figures WEFT DRAWING GRIPPER FOR LOOMS BACKGROUND OF THE INVENTION Continuous weft supply looms are known wherein a pair of reciprocating weft-carrying grippers-one feeding and one drawing gripper-insert the weft in the warp shed, exchanging weft yarns at the center of the shed.

This invention relates to an improved drawing gripper for such looms, namely to a gripper which grasps the weft yarn at the center of the shed, taking it away from the feeding gripper which has carried the thread thereto, and draws the thread outside the shed leaving it there.

In particular, the gripper according to this invention is of the type comprising a stiff gripper body provided with an elongated lower branch having a small raised end portion onto which is urged in elastic engagement, for locking the weft yarn, an oscillating metallic arm which is also stiff and has a hook end for grasping the weft yarn.

SUMMARY OF THE INVENTION It is an object of the invention to make this gripper, of a type already known in to the art, particularly suited for working yarns with low and very low counts, for which up to now continuous weft supply looms have always given a bad performance. For this purpose, the invention provides for a drawing gripper of the type described above, characterized in that to the small raised end portion of the gripper lower branch is applied a thin metal covering on its surface of engagement with the oscillating hook arm, said covering extending in the shape of a cantilever lamina for a short length along and above the non-raised portion of the branch. Preferably, the metal covering is provided at one end with a square tailpiece for its connection to the end of the gripper lower branch.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be illustrated in detail, by mere way of example, with reference to the accompanying drawing which shows a practical embodiment thereof, and in which:

FIG. 1 is a general side view of the drawing gripper according to the invention;

FIG. 2 is an enlarged side view of the end of the same gripper with the oscillating element raised, of which FIG. 3 is an enlarged partial view from the top with the oscillating element broken away; and

FIG. 4 is a perspective view, according to the arrow IV of FIG. 3, of the end portion of the lower branch of the drawing gripper according to the invention and of its metal covering.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in greater detail, the drawing gripper according to the present invention comprises a gripper body 1 of known configuration comprising a horizontal base portion 1' and an upright portion 2 at the far side of the base portion 1 as seen in FIG. 1. Base portion 1' is extended forwardly by a horizontally extending portion 1" that terminates forwardly in a horizontal lower branch 3. Branch 3, at its end which appears as the left end in FIGS. 1 and 2, terminates in a small raised end portion 7 whose upper surface is above the level of the rest of the upper surface of lower branch 3.

Upright portion 2 is forwardly extended by a further upright portion 2 and a still further upright portion 2" that terminates forwardly in a protecting member 8 (see FIG. 3).

Pivoted at its rear end to the rear of portion 2, for vertical swinging movement about a horizontal axle 4, is a generally horizontally extending metal arm 5. Arm 5 terminates at its free end, which is the left end seen in FIGS. 1 and 2, in a hook 6 comprising a portion that rises from the end of arm 5 and then extends laterally as seen in FIG. 3 and then rearwardly above branch 3 to the rear or right end of the hook as seen in FIGS. 1 and 2. The portion of hook 6 that thus extends rearwardly above branch 3 receives between itself and branch 3 the weft yarn as seen in FIG. 2. Spring means (not shown) acts on arm 5 continuously to urge arm 5 toward lower branch 3 thereby releasably to engage arm 5 with lower branch 3 to hold the weft yarn between them. Cam means (not shown) are provided in the path of the drawing gripper to swing arm 5 from the FIG. 1 position to the FIG. 2 position to release the yarn at an appropriate point in the path of movement of the gripper. These aspects of the operation of the device of the present invention are described in greater detail in Swiss Pat. No. 482,852.

According to the invention, the end of the branch 3 is formed with its small raised portion 7 provided with a metal covering 9 having a portion thereof extending in the shape of a cantilever lamina 10 for a short length along and above the non-raised portion of the branch 3. As can be seen from the drawing, and in particular from FIG. 4, the covering 9 comprises a flat, thin covering, being applied on the engaging surface of the small raised portion 7 of the branch 3, so as to project with its lamina l0, and a square tailpiece 11. The weft yarn is thus grasped between hook 6 and lamina 10, as will be evident from a comparison of FIGS. 1, 2 and 3.

The lamina 10 of the covering 9 according to the invention is slightly arch-shaped on its side facing the protecting member 8, thereby to have reduced thickness compared to the widest portion of the covering itself (see FIG. 3). The tailpiece 11 contacts the inner side 12 of the end of branch 3 and serves to fix the covering 9 by means of protuberances or further bent portions of the tailpiece 1 1 itself incorporated into the plastic material forming the branch.

It is understood that the manner of fixingthe covering 9 with its cantilever lamina 10 to the branch 3 could be other than that illustrated and that the shape of the covering itself could consequently vary as regards the form and arrangement of the tailpiece 11.

At the free end, the lamina 10 terminates in a tip portion 13 bent towards the protecting member 8 and slanting towards the branch 3, which can be provided, in correspondence of the tip 13 itself, with a notch 14 for housing the same in the event of severe stress and deformation of the lamina 10.

It is important to observe that, with the arrangement adopted, the drawing gripper can handle, even at a high loom speed, yarns with very low counts and delicate yarns in general, without having to reduce the speed of the loom on which the gripper is mounted and without frequent breaking of the threads taking place. The reason for this is to be found in the fact that with this arrangement a very smooth and progressive engagement of the thread grasped by the drawing gripper is obtained, this engagement being fovored by the invitation offered by the bent slanting tip 13.

Practice has shown that in a loom equipped with a pair of grippers comprising the drawing gripper according to the invention, it has been possible-in the case of yarns with very low counts-t increase the speeds of about 200 strokes per minute of the most improved known looms to speeds of 230-240 strokes per minute and over, with no particular inconveniences arising during work, but on the contrary, with a reduced breaking of the weft yarns.

lclaim:

1. In a drawing gripper for carrying weft yarns in stationary weft supply looms, comprising a rigid gripper body having an elongated lower branch having a small raised end portion, a rigid oscillating arm, means mounting said arm for oscillation into and out of engagement with said raised portion, said arm being resiliently urged into engagement with said raised end portion, said oscillating arm having a hook end for receiving a weft yarn; the improvement comprising a thin metal covering on the surface of engagement of said raised end portion with said oscillating arm, said covering having a portion thereof extending in the shape of a cantilever lamina beyond said raised portion for a short distance along and above said lower branch.

2. A drawing gripper as claimed in claim 1, said metal covering having at one end a square tail piece of greater thickness than the rest of said covering for connecting said covering to said lower branch.

3. A drawing gripper as claimed in claim 1, said short length of said metal covering terminating in an end away from said raised end portion of the lower branch, said end of said short length being inclined downwardly toward said lower branch.

4. A drawing gripper as claimed in claim 3, and a recess in said lower branch in registry with said inclined end portion to receive said inclined end portion.

5. A drawing gripper as claimed in claim 1, in which said gripper body and lower branch are of plastic.