GB1564417A

GB1564417A - Yarn storage device for warping machines

Info

Publication number: GB1564417A
Application number: GB4560776A
Authority: GB
Original assignee: LIBA Maschinenfabrik GmbH
Current assignee: LIBA Maschinenfabrik GmbH
Priority date: 1975-12-01
Filing date: 1976-11-02
Publication date: 1980-04-10
Also published as: DE2553943C3; DE2553943B2; DE2553943A1

Description

(54) YARN STORAGE DEVICE FOR WARPING MACHINES (71) We, LIBA MASCHINENFABRIK G.ntb.H., Postfach 1120, 8674 Naila, Germany (Fed. Rep.), and a German company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a yarn storage device for warping machines.

It is known practice to install yarn storage devices immediately before warping to simplify the tying of broken yarn. Such devices are of particular importance if breakage of individual yarn occurs and the free yarn end is taken up by the warp beam before the machine can be stopped by a yarn checker.

This yarn end must now be traced to tie it to the second yarn end coming from the creel. The storage device is used for this operation. The warp beam drive is reversed, and the warp sheet runs backward and is stored in meanders or loops between two sets of rolls moving in opposite directions.

It is very important to keep the warp sheet taut during this procedure. If possible, it should be stored and released, i.e. wound onto the warp beam from the storage device, with the tension preset for the warping process. All conventional storage devices heretofore in use, either operating with weights or driven by motors, have failed to meet this requirement satisfactorily. Tension peaks and drops have occured due to different friction coefficients, different speeding-up times of storage and beam drives, respectively, varying leverage conditions, and other reasons.

They have caused over-stretching and breakage of yarn, despite various attempts to avoid this by expensive synchronizing devices operating with microswitches (see for example U.S. Patent Specification No. 2,302,700).

It has, therefore, been proposed (U.S.

Patent Specification No. 3,550,827) to sense the tension of the warp sheet running on two sets of storage rolls mounted on carriages movable in opposite vertical directions, by means of a roll resting on the warp sheet and controlling the speed of the festooning movement of the roll sets. This control was to be effected by very expensive fluid pressure means fixedly mounted, together with the sensing roll, on a frame adjacent to the storage rolls. Separate transmission rods were required for the sensing roll, and the initiation of the control operation was considerably delayed.

According to the invention there is provided a yarn storage device for warping machines, comprising a frame; a first set of storage rolls rotatably mounted in said frame; a carriage adapted to be moved up and down with respect to said frame; a second set of storage rolls rotatably mounted in said carriage, said two sets of storage rolls being adapted to form storage loops in the warp sheet; driving means for moving said carriage; a rocking arm pivoted on said carriage and adjustably loaded; a sensing roll rotatably mounted on the free end of said rocking arm, said sensing roll being adapted to detect the warp tension; and an actuator arranged on said carriage and operable by said rocking arm to control said driving means.It is particularly advantageous when the rocking arm has its shaft placed on the carriage, and its length so chosen that the sensing roll and the rocking arm shaft are situated at opposite ends of the storage device.

One embodiment of yarn storage device according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is an elevational view of the storage devices; and Figure 2 is a frontal view, partly in section, of several elements of the storage device.

Referring to the drawings, the storage device comprises a frame generally designated by 1. A first set of storage rolls 2 is rotatably, but in fixed relation to the warp sheet, mounted on poles 20, 21 of the frame 1. Between the individual storage rolls 2, there are provided a second set of storage rolls comprising reciprocable or dancer rolls 4 rotatably mounted on a carriage 3. This carriage is adapted to slide up and down along frame posts 22, 23 to releasably store the warp sheet 5 coming from the creel (not shown) in meanders or loops 24. The sheet is to be taken up by a warp beam (not shown) of conventional construction and drive. If no yarn breakage has occurred, the carriage 3 with the rolls 4 is in an upper position (not shown) in which the rolls 4 do not touch the warp sheet.

The carriage can be raised or lowered by a controllable DC gear motor 6 secured to the carriage, and suitable gear means are provided consisting of a worm gear 7 driving a shaft 8, and two rack-and-pinion gears with gear wheels 19 fastened to the shaft 8 and two racks 18 secured to the frame posts 22 and 23, respectively. Thus, the motor will raise or lower the carriage with the storage rolls 4 as indicated by the arrow 17 depending on the desired amount of storage within the loops 24.

For controlling the gear motor 6, there is provided a sensing roll 9 rotatably mounted at the free ends of rocking arms 10 of suitable length which swing around a shaft 11 arranged at the carriage 3 near the warp sheet intake. The roll 9 senses the warp sheet tension by resting on the warp sheet 5 near the warp sheet outlet of the storage device. Rocking arm 10 is provided with a lever 12 and its left end, which is loaded by a spring 13. The spring tension is chosen so as to correspond to the desired warp sheet tension if the sensing roll 9 is in its centre position. A gear wheel 14 is secured to the rocking arm shaft 11 to drive a control actuator or setting device 15 (in the embodiment a rheostat or variable resistor) for controlling the gear motor 6 in a suitable manner.

In this simple way the warp sheet tension preset for the warping process can be maintained during the whole storing and releasing procedure. A small elevation angle of the rocking arms 10 is sufficient to bring the sensing roll 9 into the required positions.

If breakage of yarn occurs, the warp sheet 5 is instantly clamped with respect to the creel in the usual manner by a clamping bar 16, and the storage procedure is started by reversing the warp beam drive. The warp beam motor inches backwards and delivers the desired warp length. It is stored by the storage device in loops 24 by moving the carriage 3 with storage rolls 4 downward.

Thus far, this is a well-known procedure in warning and beaming machines.

However, the tension of the warp sheet 5 is detected by the sensing roll 9, and the gear motor 6 for the carriage is controlled to keep the rocking arm 10 in its centre position and maintain the warp tension.

Figure 1 shows the sensing roll in an upper and a lower position as caused by greater or lesser warp tension respectively, the latter occurring when there is an initial or sudden departure from the controlled situation. In Figure 2 the sensing roll 9 is shown in the lower position only, which is the initial to zero position. It should be noted that, before starting the storage procedure, the carriage 3 is in so high a position that both the rolls 4 and roll 9 are clear of the warp beam which rests substantially straight on the rolls 2 only. It will be realised that shortly after starting the storage procedure, i.e. turning on the motor 6 to lower the carriage 3, the roll 9 will dive into the warp sheet 5 first and well ahead of the rolls 4, form a loop, and sense the warp tension.

This instantly and without delay initiates the control operation.

It is to be understood that the yarn storage device may incorporate control means other than those particularly shown and described.

Compared with the known arrangements, the illustrated embodiment provides a storage device of simplified construction which requires less space, and always renders a sensitive and fast control of the storage roll movement without special transmission rods for the sensing roll assembly. Also, the requirement for complicated and delicate synchronising equipment is avoided.

WHAT WE CLAIM IS: 1. A yarn storage device for warping machines, comprising a frame; a first set of storage rolls rotatably mounted in said frame; a carriage adapted to be moved up and down with respect to said frame: a second set of storage rolls rotatably mounted in said carriage, said two sets of storage rolls being adapted to form storage loops in the warp sheet; driving means for moving said carriage: a rocking arm pivoted on said carriage and adjustably loaded; a sensing roll rotatably mounted on the free end of said rocking arm, said sensing roll being adapted to detect the warp tension; and an actuator arranged on said carriage and operable by said rocking arm to control said driving means.

2. A yarn storage device according to claim 1, in which the sensing roll is arranged adjacent to the intake or the outlet of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. along frame posts 22, 23 to releasably store the warp sheet 5 coming from the creel (not shown) in meanders or loops 24. The sheet is to be taken up by a warp beam (not shown) of conventional construction and drive. If no yarn breakage has occurred, the carriage 3 with the rolls 4 is in an upper position (not shown) in which the rolls 4 do not touch the warp sheet. The carriage can be raised or lowered by a controllable DC gear motor 6 secured to the carriage, and suitable gear means are provided consisting of a worm gear 7 driving a shaft 8, and two rack-and-pinion gears with gear wheels 19 fastened to the shaft 8 and two racks 18 secured to the frame posts 22 and 23, respectively. Thus, the motor will raise or lower the carriage with the storage rolls 4 as indicated by the arrow 17 depending on the desired amount of storage within the loops 24. For controlling the gear motor 6, there is provided a sensing roll 9 rotatably mounted at the free ends of rocking arms 10 of suitable length which swing around a shaft 11 arranged at the carriage 3 near the warp sheet intake. The roll 9 senses the warp sheet tension by resting on the warp sheet 5 near the warp sheet outlet of the storage device. Rocking arm 10 is provided with a lever 12 and its left end, which is loaded by a spring 13. The spring tension is chosen so as to correspond to the desired warp sheet tension if the sensing roll 9 is in its centre position. A gear wheel 14 is secured to the rocking arm shaft 11 to drive a control actuator or setting device 15 (in the embodiment a rheostat or variable resistor) for controlling the gear motor 6 in a suitable manner. In this simple way the warp sheet tension preset for the warping process can be maintained during the whole storing and releasing procedure. A small elevation angle of the rocking arms 10 is sufficient to bring the sensing roll 9 into the required positions. If breakage of yarn occurs, the warp sheet 5 is instantly clamped with respect to the creel in the usual manner by a clamping bar 16, and the storage procedure is started by reversing the warp beam drive. The warp beam motor inches backwards and delivers the desired warp length. It is stored by the storage device in loops 24 by moving the carriage 3 with storage rolls 4 downward. Thus far, this is a well-known procedure in warning and beaming machines. However, the tension of the warp sheet 5 is detected by the sensing roll 9, and the gear motor 6 for the carriage is controlled to keep the rocking arm 10 in its centre position and maintain the warp tension. Figure 1 shows the sensing roll in an upper and a lower position as caused by greater or lesser warp tension respectively, the latter occurring when there is an initial or sudden departure from the controlled situation. In Figure 2 the sensing roll 9 is shown in the lower position only, which is the initial to zero position. It should be noted that, before starting the storage procedure, the carriage 3 is in so high a position that both the rolls 4 and roll 9 are clear of the warp beam which rests substantially straight on the rolls 2 only. It will be realised that shortly after starting the storage procedure, i.e. turning on the motor 6 to lower the carriage 3, the roll 9 will dive into the warp sheet 5 first and well ahead of the rolls 4, form a loop, and sense the warp tension. This instantly and without delay initiates the control operation. It is to be understood that the yarn storage device may incorporate control means other than those particularly shown and described. Compared with the known arrangements, the illustrated embodiment provides a storage device of simplified construction which requires less space, and always renders a sensitive and fast control of the storage roll movement without special transmission rods for the sensing roll assembly. Also, the requirement for complicated and delicate synchronising equipment is avoided. WHAT WE CLAIM IS:

1. A yarn storage device for warping machines, comprising a frame; a first set of storage rolls rotatably mounted in said frame; a carriage adapted to be moved up and down with respect to said frame: a second set of storage rolls rotatably mounted in said carriage, said two sets of storage rolls being adapted to form storage loops in the warp sheet; driving means for moving said carriage: a rocking arm pivoted on said carriage and adjustably loaded; a sensing roll rotatably mounted on the free end of said rocking arm, said sensing roll being adapted to detect the warp tension; and an actuator arranged on said carriage and operable by said rocking arm to control said driving means.

warp sheet and is adapted to move between said storage rolls, and in which said actuator is operable by a shaft coupled with said rocking arm in accordance with its elevation angle.

3. A yarn storage device according to claim 2, in which the shaft of said rocking arm is so arranged on said carriage and the length of said rocking arm is so dimensioned that said sensing roll and said rocking arm shaft are situated near opposite ends of the storage device.

4. A yarn storage device according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawing.

5. A warping machine provided with a yarn storage device according to any one of the preceding claims.