DE1255845B - Thread cutting device for circular knitting machines - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

D 04 b

German class: 25 a - 25/05

Number: 1 255 845

File number: D 38948 VII a / 25 a

Filing date: May 18, 1962

Opened on: December 7, 1967

The invention relates to a thread cutting device for circular knitting machines for cutting of reinforcement threads with a fixed and a movable one with a vibration drive Knives, which are provided with facing cutting edges and in the area above the removed knife can be brought.

In these in the earlier patents 1195 006 and 1 220 547 proposed thread cutting devices, the knives either form a leaf spring flat * ° held scissors or they are elongated, axially moving strips with laterally attached rectangular strips Teeth whose tooth flanks are designed as cutting edges.

The invention is based on the object of ^{creating a 1} S thread cutting device, which can cut the reinforcing threads as short as possible, as well as effectively and quickly in both movement devices of the knives, and which also has relatively evenly long thread ends even at vibration frequencies between 33 and 100 periods / sec achieved.

This object is achieved by the invention in that the knives are arranged almost horizontally and can be brought approximately radially from the outside into the area above the withdrawn needles and that the Cutting of each knife are designed as V-shaped incisions, which are initially approximately at right angles to each other and then arcuate, so that at the end of the incisions they have an increasingly pointed 3 ο form ren angles with each other.

There are also already thread cutting devices (British Patent 761 975) are known in which two knives are moved axially against each other, once for each cutting process. One of these Knife has a hook-shaped front projection with an inner cutting edge, while the other knife carries a cutting edge on its front face, so that the cutting edges of the the two knives together form a V-shaped groove. However, such a knife arrangement only works during the advance of the knife provided with the cutting edge, but not during its return.

In contrast, in the thread cutting device according to the invention, a cutting effect is achieved both during the advance and during the return movement of the movable knife. Furthermore, according to the invention, the incisions in each knife are initially closed both in one direction and in the other, even when the movement begins. They open in the middle part of this movement, and they close again against moving thread trimmer
for circular knitting machines

Applicant:

Italo Delia Bella, Wörrstadt, Gutenbergstr. 9

Named as inventor:
Italo Delia Bella, Wörrstadt

Claimed priority:
Italy of November 24, 1961 (18 209),
dated December 28, 1961 (19 119)

end. As a result, the incoming thread is cut with certainty and in any case before it reaches the bottom of the cuts in the knives. The thread runs through it, into the progressively narrowing ones Area of the cutting edges and therefore cannot be pulled through the cutting area of the knife will.

It is particularly useful within the scope of the invention if the movable knife with a wider one Incision than the fixed knife is provided. This will introduce the thread into the Knife cutting much safer.

An embodiment of the invention is explained in more detail below with reference to the drawing. It shows

F i g. 1 is a perspective schematic representation of a circular knitting machine for women's stockings with attached thread cutting device according to the invention with open dial.

2 the thread cutting device in side view,

F i g. 3 the thread cutting device according to FIG. 2 in plan view,

4 shows the front end of one knife on an enlarged scale in plan view,

F i g. 5 the front end of the other knife in an enlarged view in plan view,

F i g. 6 shows a section along the line VI-VI in FIG. 2 and

F i g. 7 three different positions of the knives in their mutual alternating movement.

In the example shown, the thread cutting device on a circular knitting machine is used to manufacture

709 707/107

ment of women’s stockings. The thread cutting device 2 is by means of a boom 1 attached to the frame of the machine. F i g. 1 shows a two-system machine, the thread cutting device 2 is arranged in a zone 8 in which the needles are withdrawn so that the Thread cutting device 2 in the area of the rim for forming the reinforcement parts (e.g. stocking heel and sole) specific needles.

The thread cutting device consists of a slide 3 which is provided with a prismatic guide 4 and which can slide on a carrier which is firmly connected to the boom 1. The carriage 3 is advanced into the working position by a flexible cable 6, the jacket of which counteracts an abutment 7 fastened to the frame or carrier 5 in the known, adjustable manner. The cable 6 is operated in the known and conventional manner by a cam provided on the control drum (not shown) which controls the various working phases of the circular knitting machine. As a result, the slide 3 with the knife system at 8 is advanced into the working position in the direction of the arrow A, that is to say essentially radially to the needle ring. The caused by the cable 6 movement of the carriage 3 relative to the carrier 5 takes place against the action of a spring 15 which is articulated on the carrier 5 and the carriage 3, so that the unit of carriage 3, knife system and vibrator 13 when the train stops the cable 6 is withdrawn by the spring 15 from the area of the needle roller assembly.

The knife system carried by the carriage 3 contains two knives 10 and 11, one on top of the other, of which the lower knife 10 is firmly attached to the carriage 3 and the upper knife 11 in counteraction to a spring 12 is operated by the electric vibrator 13, for example, which to this effect acts to tighten the knife 11. The vibrator 13 is attached directly to the carriage 3 and with connected to the upper knife 11.

The two knives 10 and 11 are different at their front end on one side with one each shaped incision 20 and 21 provided, in such a way that in each mutual position of the knife an input for the thread is open, which is connected to the rotating needle roller assembly according to the respective Machine type is supplied, for example via the in F i g. 1 shown dial 24. The two knives each have two opposite cutting edges, which are approximately at right angles at the entrance of each incision lie to each other and, as shown in FIGS. 4 and 5 can be seen, are shaped differently. The cutting each have a V-shaped course, the incision 20 of the moving knife 11 being wider than the Incision 21 of the fixed knife 10.

In Fig. 7, the three positions α, b, c are illustrated, with α the middle position, b the position in which the upper knife 11 arrives at the inner stroke end and c the position in which the upper knife 11 arrives at the outer stroke end, represents.

It should be noted that during the relative movement between the two knives, the thread must pass through the space S and that the upper knife 11 performs the cutting motion twice during this period of time.

The operation of the thread cutting device is as follows:

During the normal formation of the reinforcement the control drum of the machine exercises by means of its Above-mentioned cam a train on the cable 6 and caused by the fact that the carriage 3 with the knives 10, 11 and the vibrator 13 is advanced into the cut-off zone 8 of the needle roller assembly. At the same time, the control drum can operate a switch that puts the vibrator 13 into operation. Of the Vibrator 13 can be an electromagnetic vibrator for 50 Hz alternating current. The vibrator 13 moves in counteraction to the spring 12, the knife 11 relative to the fixed knife 10. As soon as the reinforcement thread is laid out with his conventional thread guide, he runs with the last one carrying him Needle and dial 24 into the opening that is always present at the entrance of the incisions 20 and 21 and is sheared from the edges of the incisions 20 and 21. After the reinforcement is finished the cam of the control drum loosens the cable 6, and the spring 15 automatically pulls the carriage 3 with it the knives back into the rest position, while the switch, not shown, turns off the vibrator.

Claims (2)

Patent claims: 1. Thread cutting device for circular knitting machines for cutting off reinforcing threads with a fixed and a movable knife equipped with a vibration drive, which are provided with facing cutting edges and in the area above the withdrawn Needles can be brought, characterized in that that the knives (10, 11) are arranged almost horizontally and approximately radially from the outside into the area above the withdrawn needles can be brought and that the cutting edges of each knife (10, 11) as V-shaped incisions (20, 21) are formed, which initially run approximately at right angles to each other and then arcuate, so that they form an increasingly acute angle with one another at the end of the incisions. 2. Apparatus according to claim 1, characterized in that the movable knife (11) with a wider incision (20) than the fixed knife (10) is provided. Considered publications:
British Patent No. 761,975;
U.S. Patent Nos. 2,970,460, 2,824,436. Legacy Patents Considered:
German patent specifications No. 1 220 547, 1195 006. 1 sheet of drawings 709 707/107 11. 67 © Bundesdruckerei Berlin