GB2134142A

GB2134142A - Sinkers for circular knitting machines

Info

Publication number: GB2134142A
Application number: GB08400270A
Authority: GB
Inventors: Shinji Kawase; Toshiro Izumi
Original assignee: Precision Fukuhara Works Ltd
Current assignee: Precision Fukuhara Works Ltd
Priority date: 1983-01-27
Filing date: 1984-01-06
Publication date: 1984-08-08
Also published as: IT8419113A0; JPS59117691U; JPS6223828Y2; GB8400270D0; DE3402660A1; IT1173801B

Abstract

A sinker 1a for a sinker top latch needle circular knitting machine has a nose 2b and an operating butt 8a at opposite ends thereof, and is generally similar to a conventional sinker except that it has cut-out portions 11 and 12 in a bottom edge thereof between the nose 2b and the butt 8a. The cut-out portions 11, 12 provide non-continuous contact and reduced friction between the bottom edge and adjoining side faces of the sinker 1a respectively with a bottom wall and side walls of a sinker slot in a sinker bed of the knitting machine, which slot guides the sinker for reciprocating movement during the knitting process. The cut-out portions also serve to reduce the mass of the sinker. A bi-level sinker and one with two butts are also disclosed. <IMAGE>

Description

SPECIFICATION Sinkers for circular knitting machines The present invention relates to sinkers of the type used in sinker top latch needle circular knitting machines.

While the use of conventional sinkers in the aforesaid type of machine is generally satisfactory when the machines operate at conventional speeds, it is less than desirable when the machines are operated at higher speeds and when the number of feeds on the machine is increased.

The higher machine speeds and increased feeds place added stresses and strains upon the sinkers which results in added wear thereon and in increased sinker failure.

With the increased number of feeds the sinker cams are steeper so that there is increased twisting action upon the sinker operating butts, particularly with finer gauge sinkers. Also, the sinkers reciprocate at higher speeds which increases the friction between the sinker butts and cams as well as between the sinkers and the sinker slots: this results in increased wear on the sinkers in addition to the need for greater force to overcome the added friction. Further, there is increased shock upon the sinkers due to their more rapid directional changes. Increased machine speeds add to the aforesaid sinker problems in high speed knitting.

It is an intention of the present invention to overcome the above-mentioned problems.

According to one aspect of the present invention there is provided a sinker for use in a sinker top latch needle circular knitting machine, the sinker having a nose portion at one end thereof, a butt portion at the other end thereof, and a bottom edge and adjoining side side faces which in use are guided respectively in contact with a bottom wall and side walls of a sinker slot in a sinker bed of said machine, the bottom edge and the side faces having at least one cut-out portion between the nose and butt portion so as to provide non-continuous contact between the bottom edge and said bottom wall of said sinker slot and between the side faces and said side walls of said sinker slot.

In this way it is possible to reduce both the size and weight of the sinker, to reduce the friction between the sinker, the sinker cams of the knitting machine and the sinker slot, and to increase the resilience of the sinker.

According to a second aspect of the present invention, there is provided a sinker top latch needle circular knitting machine including a sinker bed having a plurality of sinker slots therein, a plurality of sinkers received within the sinker slots respectively for guidance thereby, each of the sinkers being as claimed in the second last preceding paragraph.

According to a third aspect of the present invention, there is provided a replacement sinker for a conventional sinker of the type used in a conventional sinker top latch needle circular knitting machine, both sinkers having a nose portion at one end thereof, a butt portion at the other end thereof, and a throat portion between the nose and butt portions, the distance between the butt and the throat portion being the same in both sinkers and the distance between the nose and throat portions in the replacement sinker being less than the corresponding distance in the conventional sinker.

The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a first type of conventional sinker for use in a sinker top latch needle knitting machine; Figure 2 is a side view of an equivalent sinker according to a first embodiment of the present invention; Figure 3 is a side view of a second type of conventional sinker; Figure 4 is a side view of an equivalent sinker according to a second embodiment of the present invention; Figure 5 is a side view of a third type of conventional sinker; and Figure 6 is a side view of an equivalent sinker according to a third embodiment of the present invention.

Figure 1 shows a conventional sinker 1 for a sinker top latch needle knitting machine which has a nose 2 at its forward end and a horizontal stitch drawing surface 3 forming a continuation of the nose 2, a throat 4 in turn forming a continuation of the surface 3 in a web 5 adjacent to a shoulder 6.

The sinker further comprises a shank 7, an operating butt 8, a tail end 9 and a bottom edge 10 which forms a straight horizontal line. The sinker 1 is made from flat stock and is slidably received in a respective slot in a circular needle bed (not shown) of the knitting machine; the depth of the slot (symbolically indicated at A) is generally equal to the height of the sinker shank 7. A plurality of such sinkers alternate with a plurality of needles in making a knitted fabric, which is walewise tensioned and which exerts pressure upon the sinker noses as it travels over them.

Sinker loops are formed when the needles draw loops over the stitch forming surfaces of the sinkers. The throats engage with the sinker loops to retain same during the knitting process.

Figure 2 shows an equivalent sinker 1 a according to the present invention, which has a projection 2a at its forward end ahead of a round nose 2b, and a horizontal stitch drawing surface 3a formed as a continuation of the surface 3a in a neb 5a adjacent to a shoulder 6a. The sinker 1 a also includes a shank 7a, an operating butt 8a, a tail end 9a and mutually aligned bottom edge portions 1 0a, 1 0b and 1 Oc which are spaced apart by cut-out portions or openings 11 and 12: the portions 11 and 12 are of trapezium shape and are substantially equal in length. These cut-out portions thus remove parts of the bottom edge and adjoining areas of the sinker.

Comparing the sinkers 1 and 1 a shown respectively in Figures 1 and 2, the nose 2 of the sinker 1 has been shortened to provide a round nose 2b on the sinker 1 a with an extension 2a projecting forwardly therefrom. The extent of the shortening is such that the knitting function of the sinker is not interfered with. In the present instance, the length of the nose 2b (as measured from the bottom of throat 4a) is about half the corresponding length of nose 2 as measured from the bottom of throat 4. The extension 2a provides vertical support for the forward end of the sinker.

The throat 4a and the neb 5a are unchanged, but the shoulder 6a is reduced in size. The height of the shank 7 has been reduced to about one half by the cut-out portion 1 2 as shown at 7a, the resultant height of shank 7a then being about half the depth of the sinker slot. The butt 8a is unchanged but the tail 9a is reduced. The sinker 1 a is slidingly supported in the respective sinker slot by the spaced edge portions 1 0a, 1 Oh and 1 Oc. The height of the cut-out portion 11 is approximately equal to the depth A of the sinker slot. The combined lengthwise extent of the cutout portions 11 and 12 is about 60% of the overall length of sinker 1 a, as measured along the bottom edge thereof.The cut-out portions have their nonparallel sides inclined at a shailow angle (as at 12a) while the interior corners are rounded (as at 11 a) to avoid concentration of the forces acting upon the sinker. On an overall basis, the weight of the sinker I a is approximately 25% less than the weight of the sinker 1, while retaining all of the normal functions of the sinker 1 in the knitting process. The area of frictional contact between the side faces of the sinker la and the side walls of the sinker slot is substantially less than the area of frictional contact between the side faces of the sinker 1 and the slot so that the force needed to reciprocate the sinker 1 a is reduced compared with that needed for the sinker 1. Less force means less sinker wear and failure.

A conventional bi-level sinker 1 5 is shown in Figure 3 as having a round nose 1 6 at its forward end, a horizontal stitch drawing surface 1 7 formed as a continuation of the nose 1 6 and throat 1 8 formed as a continuation of the surface 1 7 in a neb 19 adjacent to an upper shoulder 20. The sinker 15 also comprises a lower shoulder 21, a shank 22, an operating butt 23, a lower level bottom edge 23, an upper level bottom edge 25, and an inclined edge 26 between the edges 24 and 25.The lower portion of the sinker 1 5 (on which the edge 24 is formed) reciprocates in a lower level sinker slot whose depth (symbolically indicated at B) is equal to the height of the shank 22, while the upper portion of the sinker (on which the edge 25 is provided) reciprocates in an upper level sinker slot whose depth (symbolically shown at C) is less than the height of the nose 1 6.

Figure 4 shows an equivalent sinker 15a according to the present invention which has a projection 1 6a at its forward end ahead of a round nose 16b, a horizontal stitch drawing surface 1 7a formed as a continuation of the nose 1 6b and throat 1 8a formed as a continuation of the surface 1 7a in a neb 1 9a adjacent to an upper shoulder 20a. The sinker 15a also comprises a lower shoulder 21 a a shank 22a, an operating butt 23a, lower bottom edge portions 24a and 24b and an upper bottom edge 25a which are spaced apart by intervening, trapezium shaped cut-out portions 27 and 28. The cut-out portions remove regions of the bottom edges 24, 25 and of adjoining areas of the sinker.

Comparing the sinkers 1 5 and 15a shown in Figures 3 and 4 respectively, the outline of the sinker 1 5 has been modified to the outline of the sinker 1 5a in a generally similar manner to that employed for the sinkers 1 and 1 a, except for variations resulting from the fact that the sinkers 15 and 15a are bi-level sinkers. The forward projection 1 6a reciprocates on its bottom edge 25a in the sinker slot of depth C, the height of the cut-out portion 28 being generally equal to this depth. One side of the cut-out portion 28 merges with the inclined edge 26 at 26a. The shoulders 20 and 21 are narrowed as at 20a and 21 a.The spaced bottom edge portions 24a and 24b reciprocate in the slot of depth B, and the cut-out portion 27 reduces the height ofthe shank 22a to about half of this depth. The lengthwise extent of the cut-out portions 27 and 28 as measured along the edges 24a and 24b and 25a is about 50% of the overall length of the sinker 1 5a.

Figure 5 shows a conventional sinker 30 which is similar to that shown in Figure 1 except that its butt end is extended to provide spaced butts 31 and 32 with an additional shank 33 therebetween.

An equivalent sinker 30a according to the present invention is shown in Figure 6, which is modified in a manner similar to the modification of sinker 1 in Figure 1 to provide butts 31 a and 32a which are spaced by a reduced shank 33a having a cutout portion at 34. The resulting sinker is in contact with its sinker slot at four spaced bottom edge portions thereof instead of for its full length.

The foreshortened sinker 1 a can be used as a replacement for the conventional sinker 1 for the reason that the critical distance between the throats 5, 5a and butts 8, 8a of these sinkers is the same as shown at D in Figures 1 and 2. The distance between the nose and the throat, shown at E, has been foreshortened by half, as shown at F, to any desired distance which does not interfere with the normal sinker functions. The forward projection 2a is ahead of the nose 2b to stabilize the sinker. Similarly, the sinkers 1 5a and 30a can be used as replacements for the conventional sinkers 1 5 and 30.

Since the sinker is made lighter, its resilience normal to its direction of travel is increased, so that there is a great reduction in the shock generated upon the sinker as the direction of its reciprocating movement changes during high speed operation of the knitting machine. Also, the reduction in the area of contact between the sinker and its guiding slot results in a decreased force being needed to operate the sinker. As a result of the above, the sinker is suitable for high speed machine operation and/or with increased numbers of feeds in which wear and sinker failure is greatly reduced.

Claims

1. A sinker for use in a sinker top latch needle circular knitting machine, the sinker having a nose portion at one end thereof, a butt portion at the other end thereof, and a bottom edge and adjoining side faces which in use are guided respectively in contact with a bottom wall and side walls of a sinker slot in a sinker bed of said machine, the bottom edge and the side faces having at least one cut-out portion between the nose and butt portion so as to provide noncontinuous contact between the bottom edge and said bottom wall of said sinker slot and between the side faces and said side walls of said sinker slot.

2. A sinker as claimed in claim 1, wherein the bottom edge has at least two cut-out portions therein which are spaced apart from one another, the bottom edge being arranged in use to contact said bottom wall of said sinker slot in a region or regions between the cut-out portions.

3. A sinker as claimed in Claim 1 or 2, wherein the or each cut-out portion has the shape of a trapezium, the longer of the parallel sides of the trapezium being aligned with the bottom edge.

4. A sinker as claimed in Claim 1, 2 or 3, wherein the height of the cut-out portions or at least one of the cut-out portions is approximately equal to half the depth of said sinker slot.

5. A sinker as claimed in Claim 1,2 or 3, wherein the height of the cut-out portion or at least one of the cut-out portions is approximately equal to the depth of said sinker slot.

6. A sinker as claimed in Claim 1,2 or 3 wherein at least two cut-out portions are provided, the height of one of these portions being approximately equal to half the depth of said sinker slot, and the height of another of the cutout portions being approximately equal to the depth of said sinker slot.

7. A sinker as claimed in any preceding claim, wherein the length of the cut-out portion or portions along the bottom edge is approximately equal to 60% of the length of the bottom edge of an identical sinker not provided with the cut-out portions.

8. A sinker top latch needle circular knitting machine including a sinker bed having a plurality of sinker slots therein, and plurality of sinkers received within the sinker slots respectively for guidance thereby, each of the sinkers being as claimed in any one of the preceding claims.

9. A replacement sinker for a conventional sinker of the type used in a conventional sinker top latch needle circular knitting machine, both sinkers having a nose portion at one end thereof, a butt portion at the other end thereof, and a portion between the nose and butt portions, the distance between the butt portion and the throat portion being the same in both sinkers and the distance between the nose and throat portions in the replacement sinker being less than the corresponding distance in the conventional sinker.

10. A replacement sinker as claimed in Claim 8, wherein the distance between the nose and throat portions of the replacement sinker is approximately equal to half the length of the corresponding distance in the conventional sinker.

11. A replacement sinker as claimed in Claim 8, wherein both sinkers have a bottom edge and adjoining side faces which in use are guided respectively in contact with a bottom wall and side walls of a sinker slot in a sinker bed of said knitting machine, and the replacement sinker has at least one cut-out portion in its bottom edge and its side faces.

12. A replacement sinker as claimed in Claim 11, wherein the weight of the replacement sinker is approximately 25% less than the weight of the conventional sinker.

13. A sinker for use in a sinker top latch needle circular knitting machine, substantially as hereinbefore described with reference to Figure 2 or Figure 4 or Figure 6 of the accompanying drawings.