GB2144157A - Mechanism for adjusting the position of the upper looper in whipstitching machines - Google Patents

Abstract

Mechanism for adjusting the position of an upper looper 1 in a whipstitching machine, comprises a clamp 18 for holding the looper, the said clamp being provided with a pin 19 located inside a hole 20 perpendicular to the axis of a reciprocable and oscillatable drive rod 2, wherein the tang 21 of the looper 1 can be fixed to the said clamp 18 in a position substantially perpendicular to the said pin 19 in such away that the looper 1 can be adjusted angularly (A-A) around the said tang and vertically (B) along the said tang. Adjustment (C-C) around the pin is also possible. <IMAGE>

Description

SPECIFICATION Mechanism for adjusting the position of the upper crochet-hook in whipstitching machines Background of the invention The present invention refers to the adjustment of the position of an upper crochet-hook in a whipstitching machine, in such a way as to obtain the required adjustment between needle and crochethook, during the known movements of these.

It is known that for the correct formation of the whipstitch, the movement of the upper crochet-hook must be synchronized both with the lower crochethook and with the needle.

Attempts are made to obtain this condition by means of adjustments which, in a known manner, are actuated by adjusting the movement of the rod supporting the crochet-hook or by adjusting the position of the crochet-hook with respect to its rod.

Examples of such adjustments are described in U.S. Patent No. 3,670,677: in these examples, however, the tip of the crochet-hook is not positioned in a plane perpendicular to the needle and along a straight line vertical or parallel to the trajectory of the needle.

Summary of the invention The object and technical problem of the present invention is precisely that of achieving the means to obtain any desired synchronization between needle and crochet-hook and thus to adjust the position of the crochet in any direction, independently of the fineness of the needle used, the imperfection in the manufacture of the pivoting points of the mechanism which actuates the crochet-hook, and the dimensional differences of the levers which constitute the said mechanism.

The solution of this technical problem is obtained by means of a mechanism for adjusting the position of an upper crochet-hook in a whipstitching machine comprising a clamp for holding the crochet-hook, the said clamp being provided with a pin located inside a hole perpendicular to the axis of the rod which transmits the movement to the said crochethook, wherein the tang of the crochet-hook can be fixed to the said clamp in a position substantially perpendicularto the said pin in such a way that the crochet-hook can be adjusted angularly around the said tang and vertically along the said tang.

This mechanism has the advantage that all of the required adjustments are concentrated in the clamp holding the crochet-hook, so that ever after runningin operations, during which the couplings are allowed to settle, the synchronized conditions can easily be obtained again by repositioning the crochet-hook only.

Brief description of the drawings These and other advantages will be contained in the description which follows and is given merely by way of example and illustrated in the attached drawings, in which: Figure 1 represents the view of the movement of the upper crochet-hook in vertical section.

Figure 2 is a partially-sectioned front view of the movement of Figure 1, and Figure 3 is a perspective view of the mechanism which is the subject of the present invention.

The crochet-hook 1 is mounted on the upper end of the reciprocable and oscillatable drive rod 2 by means of the mechanism M which will be described in detail below.

The said rod 2 is articulated, by means of the pivot 3, with the rocker arm 4 which oscillates around the pivot 5. The end of the rocker arm 4, opposite the articulation pivot 3, is provided with a spherical head 6 engaged in a spherical cavity in a connecting rod 7 which is actuated by a crankshaft 8 in a known manner. The rod 2 slides in a sliding guide 9 provided with a tailpiece 9a, the axis of which intersects that of the rod 2 and which rotates in a bearing 10, the latter being fixed by means of a set-screw 11, in an appropriate cavity 12a formed in the housing 12 ofthewhipstitching machine.

A washer 13, kept in position by means of a screw 14 screwed axially into the tail piece 9a, prevents extraction of the tailpiece 9 from the bearing 10.

Numeral 15 represents the plane of the needle plate and numeral 16 represents the axis of the needle (not shown).

With the dimensions and layout of the elements shown in Figure 1, the tip la of the crochet-hook follows a path indicated by 17, which is equivalent to a large-radius circumferencial arc.

As is known, formation of the stitch occurs when there is correct synchronization between the position of the needle moving upwards and downwards along the trajectory axial direction 16 or the tip of the upper chochet-hook 1 a in such a way that this tip can intersect both the trajectory 16a of the lower crochethook (not shown) and the trajectory 16 of the needle.

In order to adjust this synchronization, the mechanism M has been realized, comprising the clamp 18 for holding the crochet-hook, which clamp is provided with a main body having a pin 19 extending outwardly thereform for reception into the hole 20 perpendicularly to the axis of the rod 2. The clamp 18 is provided with a hole which is substantially perpendicular to the pin 19 and inside which the tang 21 of the crochet-hook 1 can be fixed by means of the screw 22. With the clamp 18 thus formed, the crochet-hook 1 can be made to assume any position and hence can be adjusted angularly around its tang 21, as indicated by the arrows A-A, or vertically along the tang itself, as indicated by the arrows B-B.

Once the crochet-hook 1 is positioned in the correct position both angularly and in the vertical direction, it is locked in position by means of the screw 22 which, passing through the hole inside which the tang 21 is located, presses and locks the tang itself in the prechosen position.

The crochet-hook 1 integrally with the clamp 18 locked thereto by the screw 22 can also be adjusted in position around the pin 19, as indicated by the arrows C-C, and locked by means of the screw 23.

Further modifications or variations may be made to the mechanism in question without, however, going beyond the scope of the present invention.

Claims (5)

1. In a whipstitching machine having upper and lower crochet-hooks, a needle and an oscillatable and reciprocable drive rod 2 supporting the upper crochet-hook connected to drive means for effecting movement thereof, the improvement comprising a clamp 18, said clamp 18 including: (a) a main body having a pin 19 extending outwardly therefrom for reception into a hole 20 in the rod 2; and (b) means in said body substantially perpendiculay to said pin 19 for mounting the lower crochethook and providing for adjustment of both the angular and vertical positions of the hook.

2. Mechanism as claimed in claim 1, wherein the said clamp 18 is provided with a hole substantially perpendicular to the said pin 19, inside which hole a mounting of the crochet-hook can be fixed.

3. Mechanism as claimed in claim 2, wherein the said clamp is provided with a screw to lock the crochet-hook in the pre-chosen position.

4. Mechanism as claimed in claim 1, wherein the crochet-hook integrally with the said clamp can also be adjusted in position around the said pin 19 and locked by means of a screw.

5. A whip stitching machine constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.