US2375316A

US2375316A - Warp letoff device

Info

Publication number: US2375316A
Application number: US489529A
Authority: US
Inventors: Moessinger Albert
Original assignee: Sulzer AG
Current assignee: Sulzer AG
Priority date: 1942-07-11
Filing date: 1943-06-03
Publication date: 1945-05-08
Anticipated expiration: 1962-05-08

Description

1945 A. MOESSINGER WARP LET-OFF DEVICE Filed June 3, 1943 2 Sheets-Sheet l ATTORNEY Patented May 8,. 1945 WARP LETOFF DEVICE Albert Moessinger, Winterthur, Switzerland, as-

signor to Sulzer Freres, Societe. Anonyme,

Winterthur, Switzerland 1 Application June 3, 1943, Serial No. 489,529 J In Switzerland July 11, 1942 Claims.

Warp let-oft devices are known in which the warp beam is rotated more or less quickly by the loom, according'to the position of a tensioning device. In these warp let-off devices the engaging force of the coupling fitted between the loom and the warp beam acts on the tensioning device of the warp. The reaction of this engaging force on the tensioning device changes the Warp tension.

The invention eliminates this drawback and relates to a warp let-oif device in which the forward movement of the warp is effected by the.

loom by means of a coupling, especially a friction coupling, and the tension of the warp is kept uniform by means of a tensioning device. The invention consists in that there is provided, in addition to the axial relative movement of the two coupling parts, which is determined by the position of the tensioning device, also an axial movement, which is caused by a device driven by the loom.

The axial movement, which is produced by a cam driven by the loom, may act on the coupling part moving in accordance with the position of the tensioning device. This motion may also act on the coupling part which is not moving in ac cordance with the position of the tensioning device. The two coupling parts may be pressed together by means of one or more spring parts. The spring parts, by means of which the two coupling parts are pressed together, may exert a slight pressing force which is greater than the force causing the forward movement of the warp.

The engaging force of the coupling applied by the tensioning device may be released during the time when the tensioning device tensions the warp for the next beating up. This tensioning device, during the time when the engaging force acts on it, can by means of a clamping device be held stationary in the position in which it momentarily is. The position of the driven part of the coupling can be adjusted by the position of the tension beam; the driving part of the coupling may execute an axial reciprocating movement in addition to its rotary motions.

Fig. 1 is a diagrammatic illustration of a device according to the invention.

Fig. 2 diagrammatically shows a modified mechanism according to the invention.

Fig. 3 shows a detail of the mechanism accord ing to Fig. 2.

Fig. 4 diagrammatically shows a modification of the detail illustrated in Fig. 3.

Fig. 5 is a time-space diagram of the motions of the controlled parts of the coupling.

Referring to Fig.1 of the drawings, warp 2 running off warp beam 1 is led round a guide beam 3 and a tension beam 4, and then guided through dividing rods 4' and separated by harness 5, after which it passes into fabric 1. The forward movement of the warp 2, or the rotation of the warp beam I is effected by means of a worm wheel 45 and worm '44 and coupling part 12 which is keyed to shaft 19 and can be displaced axially. The coupling part 12 is actuated by coupling part 82, which is rotated at a constant speed by the loom through -shaft I5 by means of shaft 83 and bevel wheels 8h The warp tension beam 4 is rotatably supported in tension beam lever 65, which is itself carried in fixed fulcrum 61 and receives a turning moment through spring 26, this moment acting counterclockwise. To-an extension 69 of the tension beam lever 66 a regulating rod II is connected by means of a spring 10. This rod II is connected to the coupling part 12 through a toggle 13, I4 and a lever 15. The toggle l3, l4

is connected to lever 11 by a link 16 and is extended or contracted in time with the loom by means of cam 18 which is driven by the loom.

When the toggle I3, 14 is in its extended position (shown in full lines), the coupling part 12 is pressed against the coupling part 82 through the force of the spring I0. Any movement of the tension beam lever 66 will now change the tension of the spring 10 and therefore correspondingly modify the frictional force of the coupling. If the toggle 13, 14 is in its contracted position (shown in dotted lines), the

couplingparts

12, 82 are pulled away from each other. The regu lating rod H moves to the left under the influence of the spring 10, until the spring'lll is without tension. In that position the spring 10. ceases to act on the tension beam lever 66, so that the tension of the warp 2 is controlled only by thetension spring 26. The motion of the lever 11 which brings the toggle I3, 14 into the extended or contracted position by means of the cam 18, is, adjusted in such a way that the toggle l3, 14 is in its contracted position each time before a weft thread is beaten up. In this way the tension of the thread at each heating up of a weft thread is always kept constant.

In the arrangement according to Fig. 2 warp beam I supplies warp 2', which runs over guide beam 3' and tension beam 4" through the harness 5' and reed 6 to form fabric 1'. Between the reed 6 and the fabric 1' the weft thread 50 is inserted. The fabric 1' is led round a breast beam- 8, carried forward by operating roll 9, led

over guide roll lo and finally wound on to piece beam I. c

On the main shaft H of the loom a helical toothed wheel I! is keyed which meshes with helical toothed wheel H on shaft i5; Among the parts keyed on the shaft I5 is a bevel wheel I which meshes with bevel wheel I! revolving freely on shaft l8. On the bevel wheel II a claw which latter'is connected to tension spring The end of the otherarm 25 is firmly held between two clamping plates 28 (Fig. 3), which are pressed together by springs 29. Rollers 30 are provided at the ends of plates 28 and can be pressed apart by a key 3| connected to a free end of lever 32, thus freeing the tension beam lever 23, i. e. loosening it from the clamping plates. The lever 32 is operated, for instancethrough a curved path 33', by a cam 33 rotated by the shaft l5.

On a fixed fulcrum 34 a lever 35 is mounted, which carries an operating ,pin 36 meshing with an annular groove on the coupling part 2| The other end of the lever 35 is connected to the tension beam lever 23 through rod 38 and spring 39. The coupling part 2|l,has also an annular groove 4|! in which rests the pin of an eccentric 4| driven by the'shaft |5. The shaft I8 is supported in two

bearings

42 and 43 and carries a worm 44' which engages with worm wheel 45' connected to the warp beam Y Y The device operates as follows:

Upon rotation of the main shaft l2 or of the shaft l5, the eccentric 4| imparts an axial reciprocating motion to the coupling part 20.: Through the uniform rotation of the coupling IS, a uniform rotary motion is also imparted t this coupling part 20.- Depending on'the position of the tension beam 4" or of the tension lever 23, the other coupling part-2| is held back to a. greater or less extent from the coupling part 20. The a distance between the two coupling parts 20 and 2| is designated by letter h.

In Fig. 5a time-stroke diagram of the motion of the coupling parts 2| and 22 is given. The full line 2||'- corresponds to the axial movement of the coupling part 20,'the dotted line 2| to the motion or the position of the coupling part 2|. The distance 72 between the two coupling parts 20 and 2| is also indicated. Through its axial movement the coupling part 20 is pressed onto the coupling part-2l so that the lever 35 is also moved and the spring 39 is compressed. During the time 1., when the two couplings 2| and 22ers pressed together, the coupling part 2| will make the same rotary movement as the coupling 20 which rotates at a uniform rate. 1

The smaller the distance it, the longer will be the time if during which the coupling 2| is rotated, and the greater will be the angular rotation of this coupling or the forward rotation of the warp beam If the warp beam I has been turned somewhat too far, the warp 2 becomes somewhat slacker and longer and the tension beam 4" is moved to the left. Through this movement to the left, the

asrasie a coupling part 2| is also moved to the left, so that the distance h increases, or the angle through which the coupling part 2| is turned is diminished. In this way the forward motion of the warp beam is somewhat slowed down until the warp 2 is again shortened and the tension beam 4" returns to its normal position.

Preferably the tension beam lever 23 is kept stationary by the clamping plates'28 on the arm 25 during the beating up of the weft thread 20 into the fabric I. In accordance with the invention, during the time when the tension beam is kept stationary, the coupling part 20 is pressed against the coupling part 2|. Qonsequently the reaction exerted by the adjusting force of the coupling 2| on the tension of the warp 2 is eliminated.

Fig. 4 shows a modified mechanism for temporarily fixing'the position of the tension beam lever 23. In this case, the tension beam lever 23 has, in addition to the arm 24', also two further arms 5| which are individually connected to pistons 53 by piston rods 52. These pistons operate in two cylinders 54, which are connected by means of a central passage 55. In the connecting passage 55, a valve56 is arranged through which the passage 55 can be closed or opened. The valve 5515 moved up or down by means of a lever 53 pivoted at the fixed fulcrum 51.

In accordance with the invention the lever 53 or the valve 56 is controlled in such a way that during the time in which the two couplings 20 and 2| are pressed together, the connecting passage 55 is closed. The cylinders 54, filled with a liquid, for instance oil, will exert such a great resistance to the motion of the pistons 53, that the tension beam 4" cannot move and the reaction of the spring 39 on the tension of the warp remains ineffective. I

The position of the tension beam 4-" is not always the same. Regulation of the movement of the warp is only possible bymodifying it. By changing the position of the tension beam 4", a change is caused in the controlling force which consequently-changes the tension of the warp.

be extended as desired over for

instance

10 or 20 picks. The controlling force will also influence the tension of the warp periodically. This periodic change in the warp thread tension makes itself apparent in delicate fabrics such as silk.

By means of the execution according to this invention, this alteration in the warp thread tension is eliminated, so that very delicate fabrics can be woven without any defects appearing in them.

I claim:

1. In a'loom for weaving including a substantially continuous source of power,- a warp let-off mechanism comprising a warp beam, drive means connected with said beam and with said source of power and comprising coupling means, warp tension means, a member connected with said tension means and being responsive to changes in the tension of the warp, coupling actuating means connected with said coupling means and with said member, and control means connected with and driven by said source of power and connected with said actuating means and periodically making the connection between said member and said actuating means inefiective.

2. In a loom for weaving including a substantially continuous source of power, a warp let-oil mechanism comprising a warp beam, drive means connected with said beam and with said source of power and comprising coupling means, warp tension means, coupling actuating means connected with said coupling means and being connected with and responsive to said tension means, and other, periodically acting, coupling actuating means connected with and driven by said source of power and connected with and periodically actuating said coupling means in addition to said first mentioned actuating means.

3. In a loom for weaving including a substantially continuous source of power, a warp let-oil mechanism comprising a warp beam, drive means connected with said beam and said source and comprising two shaft members and a friction clutch for temporarily interconnecting said two shaft members, warp tensioning means, clutch actuating means connected with said clutch and also with and being responsive to said tensioning means, a cam mechanism connected with and continuously operated by that source, and control means connected with said cam mechanism and with and controlling the operation of said actuating means.

4. In a loom for weaving including a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and said source and comprising a friction clutch having two axially movable clutch members, warp tensioning means. clutch actuating means connected with one of said clutch members and also with and being responsive to said tensioning means, an eccentric mechanism connected with and continuously operated by said source and connected with and controlling the operation of the other of said clutch members. I

5. A warp let-off mechanism as set forth in claim 1 comprising resilient means interposed between said member and said tension means.

6. In a loom for weaving including a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and said source and comprising clutch means, warp tensioning means, clutch actuating means connected with said clutch means and with and being responsive to said tensioning means, and control means connected with and operated by said source and periodically interrupting the action of said tensioning means on said actuating means.

'7. In a loom for weaving including a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and said source and comprising clutch means, warp tensioning means, clutch actuating means connected with said clutch means and with and being responsive to said tensioning means, and control means connected with an operated by said source and connected with said actuating means and periodically interrupting the influence of said tensioning means on said actuating means.

8. In a loom for weaving includin a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and said source and comprising clutch means, warp tensioning means, clutch actuating means connected with said clutch means and with and being responsive to said tensioning means, and control means connected with and operated by said source and connected with said tensioning means and periodically interrupting the influence of said tensioning means on said actuating means.

9. In a loom for weaving including a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and said source and comprising clutch means, warp tensioning means, clutch actuatin means connected with said clutch means and with and being responsive to said tensioning means, and arresting means connected with and operated by said source and periodically arresting said tensioning means at the position in which they are at the moment of arresting.

10. In a loom for weaving including a substantially continuous source of power, a warp let-off mechanism comprising a warp beam, drive means connected with said beam and with said source of power and comprising coupling means, warp tension means, spring means connected with said tension means and coupling actuating means connected with said spring means and with said coupling means and being resiliently responsive to said tension means.

ALBERT MOESSINGER.