GB2053288A - Raschel machine with compound needles - Google Patents

Abstract

The movement of the tongue (4) and the shogging movement of the pattern guide bars (8) in a Raschel machine are so controlled that the needle (1) is closed immediately after completion of the over-lapping of the ground guide bars (7) and after the needle has completed at least one- fifth of its travel down from its top position (9). The rear pattern guide bars (8a) perform their under-lapping consecutively individually or in groups during swinging-in (direction of arrow) immediately after they have passed the needles (1). The front pattern guide bars (8b) do not perform their under-lapping movement until swinging-out, again individually or in groups. <IMAGE>

Description

SPECIFICATION Raschel machine with compound needles This invention relates to a Raschel machine with compound needles and a plurality of guide bars.

In a known machine of this type the needle opens during the rising movement, because the upward movement of the tongue does not start until somewhat later. Once the needle has reached its top position (about 900 of the knitting cycle), it stays in the open state in that position to about 2700, the tongue being in the top position which it reaches at about 1 300, and overlapping of the ground guide bars takes place at this time. The still open needle then starts to move down together with the tongue, the needle reaching the closed position at about 3400. Only then can underlapping of all the pattern guide bars begin, and this must be completed at about 600 of the next knitting cycle.Consequently, only about 750 of the knitting cycle is available for the underlaps, so that very considerable shogging lengths such as always occur with complicated pattern variations, necessitate a considerable restriction of the machine speed.

The object of the invention is to increase the time available for performing the pattern guide bar under-laps.

According to the present invention, a Raschel machine includes compound needles, a plurality of ground and pattern guide bars, and control means for the needles, the needle tongues and swinging and shogging of the guide bars so arranged that the rear pattern guide bars perform their underlapping during the swinging-in movement individually or in groups consecutively and immediately after passing the needle, while the front pattern guide bars perform their underlapping movement, individually or in groups, during swinging out. Preferably, the control means is so arranged that each needle is closed immediately on completion of the over-lap by the ground guide bars and at the latest by the time the needle has completed one-fifth of its travel down from its top position.

During operation of a machine constructed in accordance with the invention, the needle may be open during the rising movement as before, with the upward movement of the tongue not starting till somewhat later, so that the ground guide bar over-lapping can take place in the top position of the needle after the tongue has reached a position allowing opening of the needle. Since, however, in accordance with the invention, the pattern guide bars do not perform their shogging movement jointly, but individually or in groups, the rear pattern guide bars can perform their under-lapping successively during the swinging in of the guide bars, immediately after they have passed the needles. A period from about 1100 to 650 of the next cycle is thus available for these rear pattern guide bars, i.e. about 315".

In the preferred arrangement, the needle has already closed as a result of additional tongue travel immediately after completion of the overlapping of the ground guide bars, and at the latest by the time the needle has descended one fifth of its travel, the forward pattern guide bars can again start consecutively, as early as 2400 during the swinging out movement, until the last pattern guide bar has performed its shogging movement at about 1 600 of the next cycle, so that a total time of about 2800 is available to these forward bars.

It has already been shown that the invention makes possible an extraordinary increase in the under-lapping time for the pattern guide bars, and this makes possible greatly increased machine speeds, even with considerable shogging lengths.

Since, as already stated, the needle is closed by the additional tongue travel, immediately after completion of over-lapping, and remains closed until the knock-over position, the tongue experiences a special delayed movement, which allows a gradual transition through the top position of the additional travel to the closed position of the needle, more particularly in order to reduce the inertia forces, and this may result in a varying projection of the tongue beyond the needle head.

The greatest advantage can be obtained by using a compound needle whose breast is situated not higher than half the upward projection of the needle when the needle is in its top position.

The invention may be carried into practice in various ways but one Raschel machine embodying the invention will now be described by way of exampie with reference to the accompanying drawings, in which: Figure lisa detail of the machine during loop forming; Figures 2 to 4 are similar views with the knitting elements in different positions; and Figure 5 is a diagram showing one cycle of movement of the knitting elements, the solid-line, chain-dotted line and broken-line curves respectively denoting the movement of the compound needles, the swinging of the guide bars and the movement of the tongues, The hatched strips denote the front guide bar shogging while the cross-hatched strips denote the rear guide bar shogging. The positions in the cycle shown in Figures 1 to 4 are indicated in Figure 5 which should be considered jointly with each of Figures 1 to4.

Figures 1 to 4 show in conventional manner the knitting region of a Raschel knitting machine which employs compound needles 1 mounted in a vertically movable needle bar 2. Each needle has a tongue 4 which is secured to a tongue bar 5 and is guided in a groove 3 in the respective needle. The needles perform their strokes in the grooves of a trick or comb plate 6. In the example being described, there are two ground guide bars 7a and 7b and a plurality of pattern guide bars 8.

Figure 1 shows the elements in the knock over or bottom position, which coincides approximately with 0 of the knitting cycle as shown in the diagram in Figure 5.

Referring to Figure 2, the needle has reached its top position 9 and the guide bars are just starting to swing out in the direction of arrow 10 after the ground guide bars 7 have carried out their overlapping. Immediately after the needle 1 has been passed by the farthest forward pattern guide bar 8b the latter starts its shogging movement, i.e.

approximately at 2700 (Figure 3) after the needle has been closed by the additional travel of the tongue 4. From then on, further pattern guide bars perform their shogging movements consecutively as they move in succession forward of the needle.

As already stated the closing of the needle as shown in Figure 3 takes place immediately after the ground guide bars 7 have carried out the overlapping but at the latest before the needle 1 has covered one-fifth of its travel down from its top position.

The pattern guide bars situated farthest inwards, i.e. those adjacent the innermost guide bar 8a, can start to swing in one after the other immediately after they pass the needle, this occurring at approximately 1100. The sequence of the shogging movement of these rearward pattern guide bars can extend into the next knitting cycle, up to about 650 as shown in Figure 5. In order that the up and down movement of the tongue during the additional travel 11 shown in Figure 5 can be made relatively shallow in order to avoid appreciable inertia forces, the downward movement of the tongue lags with respect to the downward movement 12 of the needle, as will also be seen from Figure 5, so that the tongue may project (as at 13) beyond the needle head 14 as shown in Figure 4.

As can be seen from Figure 3, the machine uses a special compound needle 1 in which the needle breast 15 does not extend above the trick plate 6 more than half the distance 9 by which the needle so extends when the needle is in the raised position, to ensure trouble-free over-lapping.

Claims (6)

1. A Raschel machine which includes compound needles, a plurality of ground and pattern guide bars, and control means for the needles, the needle tongues and swinging and shogging of the guide bars so arranged that the rear pattern guide bars perform their underlapping during the swinging-in movement individually or in groups consecutively and immediately after passing the needle, while the front pattern guide bars perform their underlapping movement, individually or in groups, during swinging out.

2. A Raschel machine as claimed in Claim 1 in which the control means is so arranged that each needle is closed immediately on completion of the over-lap by the ground guide bars and at the latest by the time the needle has completed one-fifth of its travel down from its top position.

3. A Raschel machine as claimed in Claim 1 or Claim 2 in which the control means is arranged so to control the tongue that the tongue performs an additional travel to close the needle after completion of the over-lapping of the ground guide bars.

4. A Raschel machine as claimed in Claim 1 or Claim 2 or Claim 3 in which the control means is arranged so to control the tongue that the downward movement of the tongue lags on the downward movement of the needle.

5. A Raschel machine as claimed in any of the preceding claims in which each compound needle has a breast which is situated not higher than half the upward projection of the needle when the needle is in its top position.

6. A Raschel machine constructed and arranged to operate substantially as described herein with reference to the accompanying drawings.