GB2416780A

GB2416780A - Sinkers for knitting machines

Info

Publication number: GB2416780A
Application number: GB0515022A
Authority: GB
Inventors: William Ewert Shelton
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-07-28
Filing date: 2005-07-21
Publication date: 2006-02-08
Also published as: GB0515022D0; GB0416769D0

Abstract

In circular knitting machines a plurality of new loops (G,H,J) are drawn over the upper edge of modified sinker knibs avoiding contact with old loops (F) to measure the required length of yarn in each loop. Sinkers retract to release loops off the upper edge as associated needles descend, causing each loop to slide around the inclined profile of the sinker knib, to retain the pre measured length when a new loop is mehed with an old loop. The method is particularly suitable for knitting plated fabrics in that the correct juxtaposition of each yarn is preserved by the method described. Input yarn is fed at a relatively high tension to create a positive grip on the plurality of new loops preventing peaks of tension from reaching the knock over point.

Description

241 6780 IMPROVEMENTS IN OR RELATING TO KNITTING.

The present invention relates to improvements in knitting and more particularly to a method of knitting using an improved design of sinker. The invention also relates to single jersey fabric whenever knitted by the method of the invention.

For a clear understanding of the specification the following terms are defined: "Sinker" is a blade that works in conjunction with knitting needles and assists with loop formation and fabric holding down. The "throat" of the sinker is the slot which holds down the fabric. The "knib" is the part of the sinker immediately adjoining above the throat. "Forward position" of the sinker is located towards the centre of the knitting cylinder and "retracted" the outermost position.

"New loop"refers to a loop being drawn from the supply source, "old loop" is a previously formed loop and "knock-over" is the action of casting off an old loop over the hook of the needle to mesh with a new loop.

"Group" ( of loops) is the plurality of new loops formed over knibs of sinkers.

"Plated fabric" is knitted from two yarns, both of which are used in the same loop whilst positioned one behind the other. It is generally necessary to maintain a constant relationship between the two yarns so that one yarn forms the face of the fabric and the other appears on the reverse side.

"Positive grip" is the condition exerted on the new loops in the group, brought about by applying a relatively high tension to the input yarn and consequently a tight grip around the contact points of hooks and sinkers.

" Robbing" is the to and fro movement of yarn in the formation of a new loop in normal knitting. For example, if a loop length of 3mm is required, instead of the needle hook being 1.5mm below the sinkers, something like 2.5mm is drawn ( i e a 5mm loop) and when the needle is released from the nose of the stitch cam, 2mm is available to be robbed or pulled back to form the succeeding loop.

Prior art: GB 988396 describes a method of knitting circular fabric ( for ladies' hosiery) in which selected courses are produced by forming a plurality of adjacent needle loops of predetermined length prior to drawing completely each needle loop, and knitting other courses by drawing the needle loops without prior forming. This is achieved by the use of a two part stitch cam which is necessary in the knitting of a stocking because some courses such as the set-up or start of the welt, must be knitted conventionally. Other courses can be prior formed (and measured, without contact with previous loops) and thus better control the overall length of the stocking.

During normal knitting the input yarn is subjected to contact with many needle hooks and sinkers, plus high frictional contact by drawing the new loop through an old loop. This condition is exacerbated by the necessity of drawing more yarn into the new loop when the needle is at the lowest point of the stitch cam to allow yarn to be "robbed" from this loop as the associated needle is released from conact on the cam. For this reason a relatively low level of tension is needed in the input yarn.

When the prior forming method is used, with low input yarn tension, it is necessary to create an extended group of needles/sinkers to exert positive grip on the yarn and the diagram Fig 4 of GB988396 indicates a total of 15 needles/ sinkers in contact with the yarn.

In order to apply this method to large diameter knitting machines the group of new loops formed over needles/sinkers must be reduced to 3/4 needle loops or 6/7 contact points in order to achieve the number of knitting systems in a given diameter. The need for dual knitting methods is not applicable to continuous fabric producing machines and thus a high level of input yarn tension can be applied. The use of a relatively high input tension is also made possible by the limited number of frictional contact points imposed on the yarn at loop forming/measuring. The same high input tension ensures that a positive grip is exerted on the yarn in the group of new loops, preventing any snatches or peaks of tension fromthe supply source from reaching the knock-over point.

A further limitation of the method described in GB988396is the use of a standard sinker having a shallow knib which restricts the length of a new loop which can be drawn whilst avoiding contact with an old loop. It is necessary to increase the depth of the knib of the sinker to overcome this problem. It is equally essential to preserve the uniformity of the pre measured loops as they are released from the upper surface of the knib, particularly when dealing with plated fabric constructions where the yarns must be kept in correct relationship.

An objective of the present invention is to maintain control of the preformed new loops after they have released from the group of loops formed on the upper surface of the knib. A further objective is to exert a positive grip on the yarn in the group of loops in contact with at least two needles and three sinkers.

In accordance with one aspect of the invention there is provided a sinker for a circular knitting machine characterized by the knib having an upper surface spaced above the throat to permit the formation of a new loop over the upper surface without making contact with an old loop held in the throat, an inclined profile links the upper surface to the throat.

Another aspect of the invention is a method of knitting whereby a plurality or group of new loops are drawn over the upper surfaces of sinker knibs, a sinker is retracted to position a new loop at the top of an inclined profile, an associated needle descends causing the new loop to slide down the inclined profile, maintaining contact with the knib of the sinker and preserving the pre measured length of yarn in the new loop.

A further aspect refers specifically to the method of controlling yarns in the production of plated fabrics.

It is an advantage of the invention that a knitting machine fitted with sinkers in accordance with the invention does not require devices to assist the regular supply or metering of yarn to the needles. Yarn can be fed directly from the supply cone to the knitting point.

A butt is preferably provided on the sinker to define a recess between the butt and the rear portion of the knib, the recess reacting with the sinker cam to control the radial movement of the sinker.

The invention is now described by way of example only, making reference to the following drawings: Fig 1 shows a sinker S with upper surface of sinker knib at A, inclined profile B and throat C. Fig 2 shows the sinker in a forward position, new loop D drawn over surface A by needle N1,old loop E being retained on the closed latch, out of contact withn new loop D. It should be noted that the dimension from the surface A to the throat is sufficient to permit the drawing of new loop D without making contact with old loop E Fig 3 shows the sinker retracted to position loop D on the upper edge of inclined profile B in the vertical plane indicated at G. Downward movement of the needle is shown at N2 and progressively at N3 and N4 causing loop D to slide down profile B at positions G. H and J respectively. At position N5 the needle has reached knock over point to draw new loop D through old loop E. The pre measured length of loop D is preserved by contact with profile B until loop F has passed over the needle hook.

Fig 4 shows the same action as at fig 2 above when plated fabric is produced with face yarn L and backing yarn M drawn over surface A to measure these new loops. Old loops N and P are on the closed latch, out of contact with new loops L and M. Fig 5 shows the sinker retracted, ( from the forward position, shown dotted) to draw loops L and M in a controlled juxtaposition down profile B by needle hook at NO and finally at N7 to draw L and M through P and Q. loop L showing on one side of the fabric and loop M the other side.

Fig 6 shows a diagramatic plan view of sinkers S controlled by sinkers cam SC with needles at N and the position of the throat indicated at C. Sinkers S1 - S5 are held stationary in a forward position by the flat section of the cam, sinkers SO and S7 are retracted.

Fig 7 shows a front elevation in section through the needle line where needle N1 has drawn the first new loop D of the group over sinker S1, the group being created by needles N2, N3, N4, and N5 retained on the flat section of needle cam NC, sinker SO has retracted to allow new loop G to be drawn down profile B of sinker S7 by needle NO and knocked-over as needle N7 reaches the lowest point of cam NC. a.

Claims

CLAIMS.

1. A sinker for a circular knitting machine characterized by the knib having an upper surface spaced above the throat to permit the formation of a new loop over the upper surface without making contact with an old loop held in the throat, an inclined profile links the upper surface to the throat.

2. A method of knitting as in claim 1 in which the input yarn tension forming the plurality of loops is sufficiently high to exert a positive grip on the yarn when a minimum of two needle hooks and three sinkers are in contact with the yarn, to prevent snatches or peaks of tension from reaching the knitting point.

3, A method of knitting as in claims 1 and 2, in which two yarns are fed to the of the plurality to form loops in spaced relationship, upon retraction of a sinker both loops are positioned at the top of the inclined profile and maintain correct juxtaposition as they slide down the profileto the knock-over point,so that one yarn forms the face of the fabric and the other yarnappears on the t reverse side of the fabric. c.

, 4. A method of knitting plated fabric as in claim

3. .

. ,, 5. A method of knitting substantially as hereinbefore described, and with reference to and as illustrated in the accompanying drawings. (

c' 6. A knitting machine equipped with a plurality of sinkers as described and illustrated and camming for needles and sinkers to perform the methods of "' knitting as in claims 1, 2, 3 and 4, with reference to figures 1 - 7 of the accompanying drawings.

2 A method of knitting whereby a plurality of new loops are drawn over the upper surfaces of sinkers as in claim 1, a sinker is retracted to position a new loop at the top of the inclined profile of the knib, an associated needle descends causing the loop to slide down the inclined profile, maintaining contact on the knib of the sinker, and preserving the pre measured length of yarn in the new loop.

3. A method of knitting as in claim 2 in which the input tension of yarn forming the plurality of loops is sufficiently high to exert a positive grip on the yarn when a minimum of two needle hooks and three sinkers are in contact with the yarn, to prevent snatches or peaks of tension from reaching the knitting point.

4. A method of knitting as in claims 2 and 3, in which two yarns are fed to the input of the plurality to form loops in spaced relationship, upon retraction of a sinker both loops are positioned at the top of the inclined profile and maintain correct juxtaposition as they slide down the profile to the knock-over point, so that one yarn forms the face of the fabric and the other yarn appears on the reverse side of the fabric.

A method of knitting plated fabric as in claim

4.

6. A method of knitting substantially as hereinbefore described, and with reference to and as illustrated in the accompanying drawings.

7 A knitting machine equipped with a plurality of sinkers as in claim 1 and camming for needles and sinkers to perform the methods of knitting as in claims 2, 3, 4 and 5, with reference to figures 1 - 7 of the accompanying drawings. t

Amendments to the claims have been filed as follows CLAIMS.

1. A method of knitting whereby a plurality of new loops are drawn over the upper surfaces of sinkers, which feature a knib modified to provide an upper surface spaced above the throat sufficiently to permit the formation of a new loop without making contact with an old loop held in the throat, an inclined profile links the upper surface to the throat, a sinker is retracted to position a new loop at the top of the inclined profile of the knib, an associated needle descends causing said loop to slide down the profile, maintaining contact on the knib, and preserving the measured length of yarn in the loop.