Drawings, Showing an Embodiment
The single FIGURE shows a side view of the thread supply apparatus in part axial section.
The thread supply apparatus has a thread supply drum 1 formed as a pin-cage structure whose pins 2 are anchored with their ends in two end disks 3, 4 and disposed axially parallel to each other on a cylinder, not shown. The thread supply drum 1 with its end disk 3 is secured to a vertical drive shaft 5 which is rotatably journalled by ball bearings 6, 7 in a support holder 8 by which means of an attachment arrangement 9 can be placed on a suitable support ring, for example of a circular knitting machine. A pulley 11a is connected to the drive shaft 5 by which the shaft 5 can be rotated, for example over a flat belt by a drive source, not further shown.
Laterally next to the thread supply drum there is disposed at the level of its plane of circumference a lead-in thread eye 10 over which the thread 11 is guided tangentially on the rotating thread supply drum 1. The thread is derived from a supply spool, not further shown, after running through a first thread eye 12 and a thread brake 13 as well as the eye 14a of a stop-motion device.
A storage loop 14 is provided on the thread supply drum 1 consisting of several windings which is pushed downwardly by means of a feed element in form of a gear 15. The gear 15 engages in the manner shown in the FIGURE between the pins 2 of the thread supply drum 1; it is freely rotatably located by means of a ball bearing 16 on a shaft 17 connected to the support 8, so that it can be driven by the thread supply drum 1. Its shaft 17 is inclined with respect to the horizontal.
A thread pull-off eye is located laterally of the thread supply drum 1 on the side opposite the thread eye 10. Eye 19 is secured to a support element 18 which is screwed onto the support 8. Thread pull-off eye 19 has a horizontal axis and guides the thread 11 in a path 19D running off from the thread supply drum 1 to the eye 20 of a stop-motion device and a further thread eye 21 to knitting needles.
The thread pull-off eye 19 is positioned laterally adjacent to and by a predetermined amount 22 lower than the lower edge 23 of the thread supply drum 1. The thread supply drum 1 has its lower end disk 4 formed with a radially projecting ring flange 24 over whose rim edge the pay-out thread is pulled off in a path inclined downwardly from the pull-off eye 19.
A pull-off element 25 can be disposed coaxially to the thread supply drum 1 at a position in the prolongation of the axis of the thread supply drum 1. Element 25 may consist of a thread guide element rotatably located to rotate about the axis of the thread supply drum 1; or it may be positioned to be stationary below the thread supply drum 1. The thread running off from the thread supply drum can be guided over the element 25 in the thread path indicated at 26.
The thread pull-off eye 19 can be disposed height-adjustably on the support 18 in order to be able to simply adjust the distance 22 to the underside 23 of the thread supply drum 1, according to conditions.
Operation: (1) -- Positive feed:
The thread coming from the supply spool, not shown, is guided through the thread eye 10 in the described manner to the rotating thread supply drum 1 and wound on the storage winding 14 from which the thread is pulled off in path 190 through the pull-off eye 19 at the same speed with which it is supplied at 10. The storage winding 14 always maintains the same size and is continuously pushed down by the gear 15 according to the thread pull off.
If the tension of the thread taken off through pull-off eye 19 should decrease and a thread loop form between the lower edge of the thread supply drum 1 and the pull-off eye 19, it cannot be wound on the thread supply drum 1. Rather, the thread loop remains in the region below the thread supply drum 1 until the thread utilization device again takes off the normal quantity of thread and the tension of the running off thread thus again reaches the normal value, so that the thread loop is eliminated.
The distance 22 of the pull-off eye element 19 from the bottom of the thread supply drum is so chosen or adjusted that, on the one hand, no windings of the storage winding 14 fall off over the end flange 24 of the thread supply drum and, on the other, the running off thread is pulled off over the lower edge of the thread supply drum or, as in the present case, of the ring flange 24. The eye element 19 thus can guide the thread by its upper wall, when operating normally, and by its lower wall, when the thread is slack and not pulled through the opening of element 19.
(2) -- Negative, or demand feed:
In case the shown thread supply apparatus is to work selectively with a speed of thread pull-off independent of the speed of wind-up, i.e. the so-called negative-operation, the pull off element 25 is used. The thread is pulled off end-over-end, that is, over the bottom flange 24 of the drum 1. The thread is supplied to the drum 1 as before, but is then placed over the element 25 so that the thread path will be as shown in the broken line at 26. After passing over the element 25, the thread then continues through the guide eye 19.
Various changes and modifications may be made within the scope of the inventive concept.