Claims
- 1. Thread supply apparatus particularly for knitting machines having needles comprising
- a rotatable thread supply drum (1) having a lower edge structure (24), and carrying a thread storage winding (14);
- means (5, 11a) rotating the supply drum;
- means (6-9) mounting said supply drum for rotation about a vertical axis;
- thread supply means (10-13) guiding thread (11) to the drum (1) at an upper zone thereof to wind a plurality of storage windings (14) on the drum;
- and pull-off guide means (19, 20, 21; 25) guiding thread being pulled off the drum from the lowest loop of the storage winding,
- comprising
- a thread guide eye element (19) fixed in position and located, with respect to the lower surface (23) of the lower edge structure (24) of the thread supply drum (1) laterally thereof and spaced therefrom, and therebelow, by a predetermined distance (22);
- the thread guide eye element (19) having an opening to hold a thread (11) in essentially fixed position with repect to the lower edge structure (24) of the thread supply drum (1) and guide the thread with respect to a vertical direction, upwardly or downwardly, to restrain the thread from uncontrolled vertical movement;
- and a pull-off element (25) located beneath the drum positioned in a general prolongation of the axis of the drum (1) and in a thread pull-off path between the thread supply drum and the thread guide eye element;
- to permit selective removal of the threads from the drum (1)
- (a) at a speed of thread pull-off corresponding to the speed of the thread supply through the guide eye element (19) located laterally next to, and below the thread supply drum (1) in a first thread path (190) bypassing the pull-off element (25) in its travel to the needles downwardly inclined over the lower edge structure (24) of the thread supply drum (1) and through the thread guide eye element (19); or
- (b) at the speed determined by needle demand in a second thread path (26), over the lower edge structure (24) of the drum to the the pull-off element (25) end-over-end with respect to the lower edge structure (24) of the drum and then upwardly through the thread guide eye element (19).
- 2. Thread supply apparatus according to claim 1, wherein the thread supply drum (1) has, at the lower edge, a radially projecting ring shoulder (24) over which the running off thread (11) is guided.
- 3. Thread supply apparatus according to claim 1, wherein the thread guide eye element (19) is adjustable in its height level relative to the lower edge (24) of the thread supply drum (1).
- 4. Thread supply apparatus according to claim 1, wherein the pull-off element (25) is a stationary element.
- 5. Thread supply apparatus according to claim 4, wherein the pull-off element (25) is located below the guide element (19) to guide the thread in said second path (190) to extend downwardly over the lower edge structure (24) of the drum, around the pull-off element (25) and upwardly and laterally of the drum to the guide elment (19).
- 6. Thread supply apparatus according to claim 2, wherein the pull-off element (25) is located below the guide element (19) to guide the thread in said second path (190) to extend downwardly over the lower edge structure (24) of the drum, around the pull-off element (25) and upwardly and laterally of the drum to the guide element (19).
- 7. Thread supply apparatus according to claim 3 wherein the pull-off element (25) is located below the guide element (19) to guide the thread in said second path (190) to extend downwardly over the lower edge structure (24) of the drum, around the pull-off element (25) and upwardly and laterally of the drum to the guide element (19).
- 8. Apparatus according to claim 1, wherein the axis of the thread guide element (19) opening extends horizontally.
- 9. Thread supply apparatus particularly for knitting machines having needles comprising
- a rotatable thread supply drum (1) having a lower edge structure (24) and carrying a thread storage winding (14);
- means (5, 11a) rotating the supply drum;
- means (6-9) mounting said supply drum for rotation about a vertical axis;
- thread supply means (10-13) guiding thread (11) to the drum (1) at an upper zone thereof to wind a plurality of storage windings (14) on the drum;
- and pull-off guide means (19, 20, 21; 25) guiding thread being pulled off the drum from the lowest loop of the storage winding comprising
- a thread guide eye element (19) fixed in position and located, with respect to the lower surface (23) of the lower edge structure (24) of the thread supply drum (1) laterally thereof and spaced therefrom and therebelow, by a predetermined distance (22);
- the thread guide eye element (19) having an opening to hold the thread (11) in essentially fixed position with respect to the lower edge structure (24) of the thread supply drum (1) and guide the thread with respect to a vertical direction, upwardly or downwardly, to restrain the thread from uncontrolled vertical movement;
- and a pull-off element (25) located beneath the drum in a thread pull-off path between the thread supply drum and the thread guide eye element positioned in a general prolongation of the axis of the drum (1) to guide the thread at the speed determined by needle demand in a thread path (26) over both the lower edge structure (24) of the drum and the pull-off element end-over-end with respect to the lower edge structure (24) of the drum and then through the thread guide eye element (19), the pull-off element being located below the guide eye element (19) whereby the thread path (26) will extend downwardly over the lower edge structure (24) of the drum, around the pull-off element (25) and upwardly and laterally of the drum to and through the guide eye element (19).
- 10. Apparatus according to claim 9, wherein the thread supply drum (1) has, at the lower edge, a radially projecting ring shoulder (24), over which the running off thread (11) is guided.
- 11. Apparatus according to claim 9, wherein the thread guide eye element (19) is adjustable in its height level relative to the lower edge (24) of the thread supply drum (1).
- 12. Apparatus according to claim 9, wherein the axis of the thread guide element opening (19) extends horizontally.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 2608590 |
Mar 1976 |
DEX |
|
BACKGROUND AND PRIOR ART
Cross reference to related patents assigned to the assignee of the present invention and showing thread supply drums and structures therefor:
The invention relates to a thread supply apparatus for textile machines, and particularly for knitting machines.
Various thread supply devices are known, e.g. of the type with a thread supply drum carrying a storage winding to which the thread can be supplied tangentially and from which the thread can be pulled off through a pull-off eye disposed laterally next to the thread supply drum at a thread pull-off speed corresponding to the speed of thread supply.
A thread supply apparatus is known, for example, from German Patent Publication DT-AS 1 760 600, where an adjustably disposed thread pull-off eye can be moved to an operating position where it will be positioned laterally next to the thread supply drum which corresponds to the so-called positive-operation of the thread supply apparatus. Only so much thread can be pulled off through the yarn pull-off eye thereby as there is supplied to the thread supply drum from the storage winding, that is, the thread pull-off speed is limited by the speed of thread supply. The thread pull-off eye is disposed above the lower edge structure of the thread supply drum in such a way that the yarn, lying approximately in a horizontal plane, runs tangentially off the thread supply drum.
In operation, for example when associated with a circular knitting machine equipped with thread supply apparatus of this type, it has been found, however, that difficulties arise in the selective use of yarns, i.e. yarns having, respectively, S-twist or Z-twist, depending on the respective direction of rotation of the thread supply drum. With slackening tension of the pulled off yarn, according to the direction of rotation of the thread supply drum, S-twisted or Z-twisted yarn can form loops between the pull-off eye and the yarn supply, which loops are wound up on the yarn or thread supply drum, which, in turn, leads to stoppage of yarn pull-off and thus to tearing of the yarn.
Basically similar problems in the selective use of yarns with S- or Z-twist also exist in another thread supply apparatus, as described, for example, in German Patent Publication DT-AS 2,341,498, where the thread is pulled off end-over-end from the thread supply drum over a pull-off eye coaxially disposed below the thread supply drum; in positive operation, a thread guide element is disposed near the edge of the thread supply drum in the thread path between the underside of the thread supply drum and the pull-off eye. This thread guide element, not completely enclosing the thread on all sides, is formed approximately in shape of a hook open on the side which holds the run off position of the thread fixedly in space away from the thread supply drum. If individual fibers should catch or snag, as when the yarn is pulled off end-over-end, more than one winding can simultaneously be pulled off from the thread supply drum, thereby developing a loop below the thread supply drum which leads to stoppage of the knitting machine. Depending on the respective direction of rotation of the thread supply drum, a perfect thread run-off is only possible with yarns which have either S- or Z-twist. A reversal of direction of rotation of the thread supply drum presupposes, however, that first of all the hook would have to be removed and reinstalled in reversed position, which is undesirable.
It is therefore the object of the invention to create a positive-acting thread supply apparatus in which, selectively, yarns with S- or Z-twist can be worked without any switch-over of parts.
The thread supply apparatus according to the invention comprises a pull-off eye element disposed laterally next to the thread supply drum and disposed by a predetermined distance below the lower edge structure of the thread supply drum, so that the thread being pulled off is directed through the pull-off eye element in a path inclined downwardly over the edge of the thread supply drum. Other thread guide eye elements known per se can also be used.
By guiding the running off thread inclined downwardly exteriorly over the edge of the thread supply drum, yarn loops which could possibly appear with slackening of the thread tension cannot be wound back up on the yarn supply drum. They remain, as experience has shown, below the bottom of the thread supply drum so that a blockage of the thread path cannot occur. Through this arrangement of the thread guide eye elements beyond the thread supply drum, simultaneous pull-off of more than one yarn winding from the thread supply drum is also prevented.
The distance by which the pull-off eye element is situated below the lower edge of the thread supply drum, depends on the dimensions of the thread supply drum and the thread supply apparatus together. It is to be chosen in such a way that the windings of the storage loop disposed on the thread supply drum do not drop off overhead, which would correspond to a negative-operation.
In order to avoid an undesired drop off of the thread windings of the storage loop due to incorrect setting of the pull-off loop, the thread supply drum preferably has a radially projecting ring shoulder at the lower edge over which the running off thread is guided.
The height or level adjustment of the thread pull-off eye element with respect to the thread supply drum can also be simplified in that the pull-off eye element is adjustably secured relative to the lower edge of the thread supply drum.
In case the thread supply apparatus is to work selectively also in the negative-operation, i.e. with a speed of thread pull-off independent of the speed of thread supply to the thread supply drum, the arrangement can be made in such a way that a pull-off element located below the thread supply drum is provided in the thread pull-off path between the thread supply drum and the lateral thread pull-off eye element, over which the thread can be selectively guided.
US Referenced Citations (5)
Foreign Referenced Citations (4)
| Number |
Date |
Country |
| 2426680 |
May 1975 |
DEX |
| 2419793 |
Nov 1975 |
DEX |
| 1168905 |
Oct 1969 |
GBX |
| 1373884 |
Nov 1974 |
GBX |
Patent Grant
4138866
