IL45302A - Thread supply device for textile machines - Google Patents

Description

A thread supply device for textile machines Aktiebolaget ISO C. 43349 A Thread Supply Device for Textile Machines !, This invention relates to a thread supply device for textile machines, in particular knitting machines, comprising a thread drum which can be. set n rotation and upon which there is tauge.ntially wound the thread issuing from a storage bobbin' in order to form an intermediate supply and from which drum the thread may be unwound vertically over a withdrawal rim of the drum and through a withdrawal eye assembly which is disposed coaxially to said drum and which comprises a cut-off eye which may be pivoted transversely to the thread passage due to. spring action, and further comprising a thread control element which is arranged to be stationary in the area of the path of the withdrawn thread adjacent the. withdrawal rim, but which is preferably arranged to be movable out of the withdrawing path if so desired, and against 'which thread control element the thread laterally abuts due to the withdrawal tension during positive thread supply.

A thread supply device of this type is described in an earlier application. The withdrawal eye assembly in that application includes a pair of stationary withdrawal eyes in spaced relation on the imaginary drum axis between which the cut-off eye is located. If the withdrawal tension is decreased for example due to. the' fact that too much thread is supplied to the textile machine, due to the presence of dirt in the thread guide at the point of thread consumption or due to the fact that a. knot in the thread issuing from the thread drum becomes untangled, the cut-off eye may be pivoted laterally and forms between the two stationary withdrawal eyes a thread loop which extends to the side. If the resultant movement of the cut-off eye is great enough, the cut-off is activated. In this assembly, the spring action acting on the cut-off eye must be relatively great so that the cut-off eye is capable of laterally drawing the thread unwinding from the thread drum between the two withdrawal eyes in the form of a loop in the event that the withdrawal tension is reduced. This relatively great force of the spring, however, also acts on the thread during normal positive operation of the thread supply device so that the minimum tension in the thread "being supplied to the textile · . machine cannot "be reduced as much as desired.

• The invention is based on the object of designing a thre d supply device of the class described at the outset such' that it is possible to indicate an undesirably great reduction in the withdrawal tension, but nevertheless carry out positive thread supply with a very low withdrawal tension.

This object is accomplished in accordance with the invention in that the cut-off eye is the first eye of the . ithdrawal eye assembly traversed by the thread after it has passed the. withdrawal rim and that the spring load urges the cut-off eye below the area of the withdrawal rim relative to the imaginary thread drum axis, into" which area the location is moved at which the thread leaves the rim while simultaneously leaving the thread control element during a reduction o the withdrawal tension.

The invention avails itself of the following phenomenon: in a thread supply device of the recited class, the thread unwinding over the withdrawal rim of the thread drum abuts laterally on the thread control element during normal positive supply operation. This abutment is due to the fact that the vertically withdrawn thread attempts to travel around the withdrawal rim due to the withdrawal tension, but is prevented from doing so by the thread control element. Thus, only that amount of thread may be removed or withdrawn .which is released by the rotation of the thread drum.. In this way, the point at which the thread passes over the withdrawal rim is normally fixed in · space and is located adjacent the thread control element. If the tension is decreased in the withdrawn thread, less thread is removed from the drum than is released due to its rotation. The rotating thread drum pulls the unwinding thread along in the direction of rotation so that the point at which the thread leaves the withdrawal rim travels in the direction of drum rotation away from the thread control element along a circular path determined by the circumference of the withdrawal rim. Due to this movement, the thread unwinding from the drum attempts to pivot the cut-off eye, which it reaches first, in a lateral direction toward the location at which the displaced point of withdrawal is located due to the residual tension still present in the thread. Since the cut-off eye is urged in the same direction due to the spring force acting thereupon, the residual withdrawal tension in the thread and the spring force enhance one another. A very slight spring force is thus sufficient to indicate an inadmissible decrease in the withdrawal tension at the cut-off. The reduced spring force acting on the cut-off eye also causes reduced withdrawal tension in the thread during normal positive thread supply as. well.

One embodiment of the invention is illustrated in the drawing, in which :- Figure 1 is a side elevation of an inventive thread supply device in a position during normal positive thread supply and Figure 2 sho^s the. thread supply device according to Figure Λ in a position during an inadmissibly high reduction in the withdrawal tension of the thread.

In the drawing, 1 is a thread drum which is ro tably journaled in a housing 2. The housing 2 is secured to a textile machine, in particular a knitting machine, by means which are not shown I the. drawing, a plurality of supply devices corresponding to the number of knitting systems being provided in the knitting machines. The drum 1 is driven via a pin wheel 3 and a perforated belt (not shown) which cooperates with the pin wheel and which is driven synchronously with the textile machine. The thread F issues from a supply bobbin (not shown), passes through a preliminary braking means 4, a disc brake 5 and a thread monitoring device 6 to be wound tangentially upon the thread drum 1 which rotates in the direction indicated by the arrow P. The thread drum 1 is associated with an inclined cis- placement disc 7 which displaces the thread windings which are formed in axial direction along the thread drum so that an intermediate thread supply V is formed on the drum. Th,e thread is unwound from the intermediate supply V through a "braking ring 8 in vertical direction and over a lower withdrawal rim 1a of the thread drum 1. The unwinding' thread F' passes through a. ithdrawal eye assembly illustrated "by number 9 n Fig. .1. This consists of a stationary withdrawal eye 10, which is located on the imaginary axis A of the thread drum, and of a cut-off eye 11 which is the thread eye first reached by the unwinding thread F' after leaving the withdrawal rim 1a.. From the. withdrawal eye 10, the thread arrives at the working station of the textile machine, for example at the thread guide element of one. knitting system of a knitting machine. The withdrawal eye 10 is journaled at the free end of a support arm 13 which extends outside the thread drum 1' parallel to the imaginary axis A thereof and which is mounted in the housing 2 at its other end.

Directly below the withdrawal rim 1a, there is journaled on the support arm 11 by means of a hub 1 a hook 15 which can be pivo.ted in the plane of the drawing in the case of the illustrated embodiment from the position shown in the drawing, in which the mouth of the hook which is open toward the. viewer of the drawing projects into the path of the thread- F1 , into a position in which it does not project into the path of the unwinding thread. This pivotability serves to switch over from positive to intermittent thread supply and is not of prime : importance for the present invention, nor is it essential that this be a hook. It could also be any other thread control element, for example, a rod as long as the unwinding thread is not completely enclosed by this thread control element.

The cut-off eye 11 is positioned on a pivotal arm 16 which is urged by a spring (not shown) such that the cut-off eye 11 tends to pivot about an axis B, clockwise in a top i.e. out of the plane. of the drawing toward the viewer.

The mode of operation is„ as follows: The withdrawal tension in the thread section F' removes the thread vertically from the bottom of the thread -drum 1. The speed of withdrawal and the speed of rotation of the thread drum 1 are co-ordinated so that the unwinding thread F1 has a slight tendency to travel about the withdrawal rim 1a - imagined as being stationary - contrary to the direction of rotation P of.', the thread drum. The hook 15 however is in the path of this movement so that the location at which. the thread F1 leaves the withdrawal rim 1a is normally fixed in space. This normal point of withdrawal is characterized .-as Ap in Fig. 1. It lies directly above the hook 15· By maintaining the point of withdrawal Ap contrary to the direction of drum rotation, only that amount of thread-may be unwound from the drum 1 as is released during rotation of the drum at the point of withdrawal Ap above the hook . This ensures positive thread supply.

The withdrawal tension present in the unwinding thread F' causes the thread 'to be taught between the point of withdrawal Ap and the withdrawal eye 10.. This taught thread holds the cutoff eye 11 in the position shown in Fig. .1 against the spring force .acting on the eye. In this position, the cut-off eye is positioned coaxially relative to the withdrawal eye.

If the withdrawal tension is reduced, for example because the textile machine does not require as much thread as the supply device is supplying or because the. thread is jammed somewhere along the path between the supply device and the textile machine, due, for example, to dirt in the thread guide or because an already formed tangle becomes untangled . between the thread supply device and the textile .machine , the tendency of the unwinding thread F' to travel about the withdrawal rim 1a opposite the direction of rotation P due to the withdrawal tension not only stops, but also reverses so that the thread, drum 1 pulls the unwinding thread 1 along a bit in the sense of rotation P. As is shown in Fig. 2, the thread. F' thus leaves the hook 15 and escapes laterally. The point of withdrawal, i.e. the location at which the thread F' passes over the withdrawal rim 1a, moves along the withdrawal rim la in a circular path and reaches the location Ap' shon in Fig. 2 for instance. The unwinding thread F' extends "between the point of withdrawal Ap' and the withdrawal eye 10. The point of with-•drawal Ap 1 is displaced- along a circle defined by the withdrawal rim 1a in the same direction in which the spring attempts to . urge the cut-off eye 11. The residual tension in the thread F' thus coacts with the sprin force to pivot the cut-off eye 11 into the position shown in Fig. 2 in which it de-activates the textile machine "by means of a conventional switching assembly ■■ (not shown) and/or activates an indicating means 1'7.

The invention is not limited to the embodiment described : herein. As already mentioned, the hook may be replaced by a rod or by another thread control element as long the thread F' . is permitted to leave^ the thread control element laterally when the withdrawal tension is reduced. The cut-off eye 11 does not have to be eye-shaped in configuration. A guide element abutting on the unwinding thread laterally would also suffice. It is-only essential that no other thread guide element be located between the withdrawal rim 1a and the cut-off eye 11. This would make it necessary for the cut-off eye to laterally, deflect the thread in the. form of a loop when the withdrawal tension decreases.

In principle, the invention may also be used on thread . supply devices with stationary thread drums. In this case, a rotating winding element is provided which would have to be connected to the thread control element. If the thread supply becomes excessive, the unwinding thread leaves the control element in this case as well as arrives in a position in which it coacts to pivot the cut-off eye.

Claims (1)

1. 45302-2 - 7 - WHAT IS CLAIMED IS:- A thread supply device for textile machines, in particular knitting machines, comprising a thread drum which can be set in rotation and upon which thereis . tangentially wound the thread issuing from a storage bobbin in order to form an intermediate supply and from which drum the thread may be unwound vertically over a withdrawal rim of the drum and through a withdrawal eye assembly which is disposed coaxially to. said drum and. which comprises a cut-off eye Which may-be pivoted transversely to the thread passage due to spring action, and further comprising a thread control element which is arranged to be stationary in the area of the path of the withdrawn thread adjacent the withdrawal rim, but which is preferably arranged to be movable out of the .withdrawing path if so desired, and against which thread control element the thread abuts laterally due. to the withdrawal tension during positive thread supply, characterized in that the cut-off eye is the first eye of the withdrawal eye assembly traversed by the thread after it has passed the withdrawal rim and that the spring load urges the cut-off eye below the area of the withdrawal rim relative to the imaginary thread drum axis, into which area the location, at which the thread leaves the withdrawal rim, is moved during a reduction of the withdrawal tension while simultaneously leaving the thread control element. For the Applicants DR. REINH0L0 COHN AND PARTNERS