Yarn Breakage Stop Motion Device for Textile Machines

1. Field of the Invention

The invention concerns a yarn breakage stop motion device for textile machines, particularly tufting machines, consisting of a number of plates corresponding to the number of the yarns to be monitored. The plates are equipped with an eye on both ends, one which serves to guide a yarn to be monitored and the other to place the plate on a carrier axle. The plurality of plates together form a register in the pivoting range whereof a photocell acting on the drive mechanism of the machine is arranged.

2. Background of the Prior Art

In a known type of a yarn breakage stop motion device, the plates are aligned freely on the carrier axle, so that they are not only essentially freely displaceable in the lateral direction, but are also free to tilt within a range determined by the unavoidable manufacturing tolerances of the guide axle and the eye of the plate. In another known type of a yarn breakage stop motion device, the plates are guided in a grooved rail consisting essentially of a square strip into which guide slots are machined with a predetermined spacing in widths corresponding to the thickness of the plates and parallel to each other. The rail additionally provides a longitudinal bore in the area of the webs formed by the machining operation. The bore has a diameter corresponding to that of the eye to receive the carrier axle.

Both known yarn breakage stop motion devices have certain significant disadvantages. One of the essential disadvantages consists of the substantial installation effort required in the case of the removal or insertion of one or several plates into the register. For example, during damage or the resetting of the machine for a product with a different yarn distribution the plates frequently require removal or additional plates need to be inserted. In such a case, it is necessary initially to disassemble the entire register, followed by the removal of all of the plates unilaterally from the terminal plate to the damaged plate. In case of a comb register, this is done after first retracting the guide axle for the register. The insertion of the replacement plates follows and then reassembly of the register using the plates previously removed is required. Resetting of the machine by installing the register and threading the previously pulled yarn then comprises the final step.

The same effort is required in the case of a reequipment of the machine. The only difference is that in this instance, depending on the type of resetting for a product with a higher or lower yarn division instead of replacing a plate, the removal or addition of a plate or several plates is required.

The second primary disadvantage of the known yarn breakage stop motion device is that they do not permit the setting or maintenance of an accurately defined yarn tension. The further consequence of this disadvantage is that the monitoring of machines so adjusted is not possible, for example, for the production of tufted, looped fabric with a yarn breakage stop motion device. It is known that that the production of tufted, looped or boucle fabrics is effected in a manner wherein the yarn needled through the basic fabric is held by a gripper during the pulling of the needle in order to form a loop with only the loop that is formed being held to the point in time wherein the needle reaches its upper dead center and is then released. As a precondition of the application of a yarn breakage stop motion device in machines equipped in this manner, it is again necessary to adjust the drop weight of the plates with high accuracy to a low value and to maintain this value permanently. This is required in order to safely prevent the pulling of the loop just formed under the weight of the plate. The known yarn breakage stop motion devices do not permit such an accurate weight adjustment.

It is the object of the present invention to provide a yarn breakage stop motion device that makes possible a simple removal and/or insertion of plates to replace damaged plates or to alter the division of yarns. This object is achieved according to the invention by providing a plurality of spacing rings on a carrier axle. These rings are held tensioned against each other. The spacing rings are also provided unilaterally with an annular shoulder surrounding the carrier axle. Plate members are mounted on the carrier axle through an eye at one end. The eye holds the plate member which is in turn equipped with an aperture so that the diameter of the eye corresponds to the external diameter of the annular shoulder of the spacing ring. The width of the aperture of the eye corresponds to the diameter of the internal opening of the spacing ring or to the diameter of the carrier axle. The invention provides a yarn breakage stop motion device, whereby in the simplest possible manner, it is possible to replace damaged plates and to reset the installation for a different yarn division without a necessary removal of the register from the machine and without pulling all of the yarns out of the guides just to take off plates in addition to the damaged or superfluous ones. A method of replacing damaged plates of the yarn breakage stop motion device is, therefore, also provided. This method merely requires releasing the clamping device holding the spacing rings against each other (such as by release of a simple threaded nut) and shifting of the spacing rings on the carrier axle to form a gap corresponding to the thickness of a plate between the plate to be removed and the adjacent spacing ring followed by removal of the plate desired by freeing the plate laterally of the annular shoulder holding it and extracting it by means of the aperture in the locating eye over the carrier axis. The insertion of the replacement plate is effected in the reversed order. It is also possible to alter the yarn division by removing or inserting plates. Thus a further method is provided wherein plates are removed or additional plates are inserted. In this procedure, the spacing rings not occupied by plates remain on the carrier axle as blind rings in the register. These spacing rings are clamped in following the adjustment of the register to the yarn division desired without interfering with the yarn breakage stop motion device.

In a preferred embodiment of the invention, the carrier axle is displaceably supported in a slot or elongated hole guide on a support frame and a counter bearing rod is also displaceably supported in a second elongated hold guide. In this manner, the exact adjustment of the drop weight of the plate for any requirement is made possible. At the same time, a setting for the low yarn tensions are permitted in the production of tufted looped fabrics. In this embodiment, the values set remain constant over long periods of time in contrast to the known yarn breakage stop motion devices. For example on the one hand, the plates are guided satisfactorily in all directions. On the other hand, the tilting of the plates and the penetration of dirt or dust between the guiding surfaces to interfere with their functioning is prevented as the result of the compact clamping without clearance of the spacing rings against each other.

The invention is illustrated in the drawings in the form of an example.

In the drawing:

FIG. 1 shows a top view of a yarn breakage stop motion device;

FIG. 2 illustrates a view of a plate member;

FIG. 3 shows a side view cross section and a front view cross section through a spacing ring; and

FIG. 4 shows the manner in which the spacer rings are held together on the axle of the present invention.

In FIG. 1 of the drawing, 1 designates the support frame mounted in a stationary fashion on the frame of the yarn breakage stop motion device. The support frame 1 comprises a plurality of plates 2 which are aligned in fundamentally arbitrary numbers adjacent to each other. The plurality of plates is not seen in FIG. 1 as such plates are aligned behind one another and mounted on a carrier axle 3. A photocell 4 is located within the pivoting range in the direction of the dropping plates. The photocell acts on the drive machanism of the machine and in cooperation with the plates such that upon the breaking of the yarn 6 passing through the eye 5, the dropping plate intersects the beam of light to the photocell 4 thereby generating a pulse which in turn deactivates the machine drive.

On the carrier axle 3, as also illustrated in FIGS. 2 and 3, an arbitrary number of spacing rings 7 are held against each other by means of a clamping device (not shown). The spacing rings are provided unilaterally as shown in FIG. 3 with an annular shoulder 9. In FIG. 2, an eye 10 at one end of each plate serves to support such plates 2. The eye also displays an aperture 11. In this design the guiding diameter of the eye 10 corresponds to the external diameter D.sub.1 of the annular shoulder 9 and the width W of the aperture 11 corresponds to the diameter W.sub.1 of the inner bore 12 of the spacing ring 7. This inner bore 12 generally corresponds to the diameter of the carrier axle 3.

The carrier axle 3 as illustrated in FIG. 1 is supported adjustably in an elongated hole guide 14 in the support frame. A counter bearing rod 16 is located adjustably and displaceably in an adjacent elongated hole 15 and is provided in the pivoting range of the plates 2 in the direction of the yarn tension. This arrangement renders possible (by means of the mutual adjustment of the axle 3 and the rod 16 for the purpose of alignment) the accurate setting of the drop weight of the plate and thus of the tension applied to the yarn being guided. The tension is adjustable to sufficiently low values so that the monitoring even of tufting machines set for the production of looped fabrics is possible.

The clamping of the spacing rings on the carrier axle against each other may be effected by any suitable means. Usually, the clamping means comprises threads on the other or on both sides of the carrier axle and one or two threaded nuts to hold the rings against the shoulder. FIG. 4 shows the arrangement in which two nuts 20 are provided on threads 22 on the ends of axle 3.

In any arrangement of the clamping means, it is however particularly advantageous to permit insertion and/or removal of one or any number of the plates without disassembling the entire apparatus.

In order to remove or insert one or several plates, it is then sufficient to initially release a threaded nut far enough so that a gap corresponding at least to the thickness of a plate is formed between a spacer ring and the annular shoulder of the immediately adjacent spacer ring. The spacer rings are then moved on the carrier axle so that a similar gap is formed next to the annular shoulder of the plate to be removed or inserted. The plate is then extracted by initially pushing it off the annular shoulder laterally and then moving it outwardly over the carrier axle by means of the eye aperture.

The above description describes a preferred embodiment of the invention. It is to be understood however, that the invetnion is not limited to any single embodiment or feature, but should be construed to cover all modifications and alternative embodiments falling within the scope of the invention as defined by the claims which follow.