US3651669A

US3651669A - Fabric takeup for flat knitting machines

Info

Publication number: US3651669A
Application number: US84694A
Authority: US
Inventors: Wolfgang Findewirth; Helmut Irmscher; Gunther Kessler; Gunther Leubner
Original assignee: Wirkmaschinenbau Karl Marx Veb
Current assignee: Wirkmaschinenbau Karl Marx Veb
Priority date: 1967-05-11
Filing date: 1970-10-28
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28
Also published as: CH482047A; GB1291732A; SE364533B; DE2000211A1; DE2000211B2

Abstract

Fabric takeup mechanism for flat knitting machines for knitting fabrics of variable width, comprising a hook takeup including means carrying a row of hooks in a line parallel to the front edge of the fabric being knit, the hooks including a first set arranged on the left-hand side of the carrying means and a second set arranged on the right-hand side of the carrying means, the free end of each of the hooks of the first set pointing toward the left-hand edge of the fabric and the free end of each of the hooks of the second set pointing toward the right-hand edge of the fabric, means for bringing the row of hooks into engagement with the front edge of the fabric at the beginning of a knitting operation, a set of a plurality of coaxial takeup rolls and a set of a like plurality of coaxial pressure rolls each cooperating with a respective takeup roll to define a nip, the sets of rolls being positioned relative to the row of hooks to receive in the nips from the row of hooks the front edge of the fabric, and means for disengaging the row of hooks from the front edge of the fabric after the front edge of the fabric has been received in the nips.

Description

United States Patent Findewirth et al.

FABRIC TAKEUP FOR FLAT KNITTING [451 Mar. 28, 1972 FOREIGN PATENTS OR APPLICATIONS MACHINES 1,526,491 4/1968 France... ..66/149 [72] Inventors: Wolfgang Findewirth; Helmut Irmscher; 118161071 7/1969 Germanx "66/149 Gunther Kessler; Gunther Leubner a" of 7 991,975 5/1965 Great Britain ..66/149 KaILMarX'Stadt Germany Primary Examiner-Ronald F eldbaum [73] Assignee: VEB Wlrkmaschinenbau Karl-Marx-Stadt Attorney-Nolte and Nolte Kombinat fur Wirk-und Strickmaschinenbauerzeugnisse, Karl-Marx-Stadt, Ger- ABSTRACT many Fabric takeup mechanism for flat knitting machines for 22 Filed; Oct 2 1970 knitting fabrics of variable width, comprising. a hook takeup including means carrying a row of hooks in a line parallel to 1 pp 84,694 1 the front edge of the fabric being knit, the hooks including a first set arranged on the left-hand side of the carrying means and a second set arranged on the right-hand side of the carry- [5?] :LS. Cll mg means the free end of each of the hooks of the first set [5 nt.C. pointing toward theleft hand edgegofthe fabric and the free [58] Field Of Search "66/147, 149, I50, 152,242/55; end of each of the hooks of the second set p g toward the 139/304, 307, 305 right-hand edge of the fabric, means for bringing the row of hooks into engagement with the front edge of the fabric at the [56] References Ci beginning of a knitting operation, a set of a plurality of coaxial takeup rolls and a set of a like plurality of coaxial pressure UNITED STATES PATENTS rolls each cooperating with a respective takeup roll to define a 629,892 8/1899 Donner ..66 150 Sets 9 9 beillg relative hooks to receive in the nips from the row of hooks the front 2,642,096 6/1953 l-lolmes..... ..139/304 d f h f b d f h fh k 2685 896 8/1954 Holmes 139/304 e geo t e a r1c,an means or isengagmgt erowo 00 s from the front edge of the fabric after the front edge of the 3375'683 4/1968 fabric has been received in the nips. 3,376,716 4/1968 Joseph ....66/l50 3,590,602 6/1971 Blood et al.... ....66/149 7 Claims, 10 Drawing Figures a i 4 fi W 'l l 45 F u r 1 1 5 u r u 9 L 4 Jj iEi PATENTEDMAMB 1972 SHEET 2 [1F 5 wazMmew/vMw/Pn/ 9 HAY/14%? wwcwse P'A'TfNTEnmARzs 1972 SHEET 3 BF '5 WWW/7 INVENTOR BY/rfi ATTORNEY PATENTED M 2 8 m2 3. 651 ,6 6 9 SHEET UF 5 ATTORNEY P'A'TENTED MAR 2 8 I972 SHEET 5 [IF 5 MER wag 55 N/PAM wZfi .ZMTW flaw 9 H 4 6 a "w y y K w w m ATTORNEY FABRIC TAKEUP FOR FLAT KNITTING MACHINES The invention relates to a fabric takeup for flat knitting machines for knitting fabrics of variable width, consisting of a combination of a hook takeup with a roll takeup.

Fabric takeup devices are already known where the knitting head and smaller knitted pieces are taken up by a takeup comb alone and larger knitted pieces by takeup rolls. The takeup comb consists of a row of hooks which project at the start of the knitting beyond the takeup combs of the needle bed and which have wrapped around them a separating yarn. After the knit fabric is completed or after it has been transferred to the roll takeup, it is cast off the hooks of the comb by means of a mechanically operated ejector. The ejector consists of a plate extending over the entire working width of the knitting machine and having a bent edge which reaches over the row of hooks so that it drops the knitting from the hooks when it turns toward the takeup comb. In the case of long pieces of knit fabric, the fabric is taken up by the roll takeup, the back pressure rolls being displaced toward the continuous takeup roll and the knitted part being wound about onequarter of the circumference of the takeup roll.

This fabric takeup device has the disadvantage, however, that the roll takeup is arranged relatively low, so that large parts of the knitting are taken up by the comb. This has the result that the knitted fabric is distorted, due to the constant takeup force, particularly when reduction has already started. Besides, with these lengths, the knitted fabric already shrinks considerably. Special fabric width retaining means would thus have to be provided. The dropping of the knitting from the hooks by the ejector likewise does not always ensure a 100 percent release, due, among other things, to the form of the hooks, which may lead to distortion and damage in the knitted fabric. 7

Furthermore, fabric takeup devices are known in which takeup hooks arranged on bars feed the widening part or the head of a newly started knitted fabric to a takeup roll and to an arcuate guide element cooperating with the latter, which presses the knitted fabric against a part of the circumference of the takeup roll. For the automatic transfer of the knitted fabric from the takeup hooks to the takeup roll and to the arcuate guide element, the latter is in a configuration of a comb in the vicinity of the entrance point of the knitting, the spaces of which are engaged by the takeup hooks. The knitted fabric is deflected arcuately after entering the arcuate guide element and the takeup hooks move linearly. The takeup hooks remain in a position in which the knitting is taken up by the hooks. The takeup roll is driven over a ratchet gear and provides a takeup force that can be adjusted in dependence on the knitting width.

This device has the disadvantage, however, that the number of hooks for engaging the widening part or the head of the knitted fabric would have to be readjusted manually with each lot of new knitted articles or new sizes, or that new bars would have to be used. Besides the roll with the associated arcuate guide is relatively far away from the needle bed, which results in the occurrence of shrinkage. The friction conditions between the roll and the guide are not constant, so that a uniform takeup of the knitted fabric cannot always be ensured. The friction between the knitted fabric and the guide has an adverse effect on the quality of the knitted fabric, the knitted fabric receiving in addition an electrostatic charge. Furthermore, the knitting, particularly its first row, is distorted by the shape of the hooks.

It is the object of the invention to develop a fabric takeup for flat knitting machines with variable fabric width, where a clean loop pattern of the knitted material is maintained and where a minimum expenditure of assembly and attendance is necessary, due to a very simple design.

The fabric takeup provided by this invention does not have the disadvantages found in the prior art. An improved hookand-roll takeup is provided in which the two systems are arranged in a small space, close together and relatively close underneath the needle bed comb, a constant takeup force per unit knitting width is maintained, the hooks transfer their loops safely and shrinkage of the fabric is avoided without width retaining means.

According to the invention, the hook takeup for taking up the knitting head consists of hooks bent in a right angle, which are so inserted into the fabric that their free ends point in the direction of the knitting edge. The hooks are guided in hook bars. The roll takeup taking over the knitting is formed by a plurality of particularly small takeup and pressure rolls which work independently of each other and cooperate in pairs. The row of hooks of the hook takeup extending over the entire width of the machine is composed of two half rows, each of which is guided in a respective hook bar.

On each side of the machine the two hook bars are guided in a common bearing, each of which in turn is elevationally adjustably mounted on a slide.

The pressure rolls can be turned by means of pressure levers toward the stationary takeup rolls. This pivotal movement is started by actuating a limit switch arranged on the guide of the hook takeup. For release, the hook bars can be displaced from the center horizontally in opposite directions by carriers arranged on a spindle having oppositely directed threads engaging respective base rails of the hook bars.

The takeup roll assemblies are each provided with a carrier plate as well as freely rotatable rollers, and the pressure roll assemblies each with a positively coupled locking plate as well as a stationary bolt serving as a return lock. For driving the takeup rolls the carrier plates are connected over chains provided with springs which are prestressed by a pull-back shaft.

For the adjustment of the takeup force of the takeup rolls all driving springs are secured on a spring tension bar which is infinitely variably displaceable by means of a threaded spindle, and for the adjustment of the pressure of the pressure rolls all springs arranged on the pressure levers are secured on a spring retaining bar which is likewise infinitely variably displaceable by means of a threaded spindle. The adjustment of the threaded spindles causes at the same time the variation of the takeup force of all takeup rolls and of the pressure of all pressure rolls.

This arrangement of the hook and roll takeup permits an early takeover of the fabric by the roll takeup. Shrinkage of the fabric is avoided without width retaining means. The design of the takeup comb including its horizontal drive ensures a safe dropping of the loops; there are no distortions of the fabric. When changing to other articles or sizes, no manual work is required. Besides, a constant takeup force at all points of the knitted fabric is ensured by the special design of the roll takeup including its drive.

The invention will be described more fully below by reference to a specific embodiment as illustrated in the drawings, in which:

FIG. 1 is a front elevation of the roll takeup;

FIG. 2 is a side elevation of the roll takeup;

FIG. 3 is a plan view of the roll takeup;

FIG. 4 is the roll takeup in a cross section;

FIG. 5 is a front elevation of the hook takeup;

FIG. 6 is a cross section of the hook takeup;

FIG. 7 is a plan view of the needles and hooks when laying an intermediate mesh;

FIG. 8 is a schematic diagram of the drive for the rotatory and the pivotal movements of the roll takeup; and

FIGS. 9a and 9b are schematic diagrams of the drive for the vertical movement of the hook takeup.

In the box legs 1 of the knitting machine are secured columns 2 on which are arranged takeup bearings 3. The takeup bearings 3 are joined with frame walls 4 by screws. The roll takeup 5 is mounted in these frame walls 4 (FIG. 1

The roll takeup 5 consists of a plurality of particularly small takeup rolls 10 and of an equal number of pressure rolls 20 (FIG. 2). The takeup and pressure rolls l0 and 20 are provided with a high friction coating or cover, such as rubber, so that the coefficient of friction is increased and the pressure between takeup and pressure rolls l0 and 20 remains relatively small. A pair of opposed rolls, viz a takeup roll 10 and a pressure roll 20, work together. Due to the division of the roll takeup into many small roll pairs a uniform knitting tension is achieved even with varying knitting width. The takeup rolls run on a shaft 11 (FIG. 2). The pressure rolls 20 are mounted rotatably on pressure levers 21 on a shaft 22 (HO. 4). They are urged by springs 23 against the takeup rolls 10. The springs 23 are secured on a spring retaining bar 24, which can be displaced by means of threaded spindles 25. An infinite variation of the pressure is thus possible. The spring retaining bar 24 and the threaded spindle 25 are positioned in adjusting lever 26 which is fixed to the shaft 22.

On the last pressure lever 21 on each side of the needle bed 35 are arranged plungers 31 on which is secured a rope 32 extending over the entire takeup width. The plungers 31 move the rope 32 with each reversal of the slide in the direction of the takeup rolls 10, thus ensuring a good sliding of the knitting over the slide-off plate 33 and avoiding sticking of the knitting due to electrostatic charges.

The drive for the movement of the plungers 31 is derived by means of Bowden cables from a pull-back shaft 16 to be described more fully below.

The drive for the feed and the pivotal movement of the roll takeup is effected by the geared motor 9, which drives

chain wheels

71 and 72 over a chain drive 8 (FIG. 8). These

chain wheels

71 and 72 rotate freely on

shafts

73 and 74 when not connected to clutches 75 by driver elements 76. The

shafts

73 and 74 are driven through carriers 76, dogs 77 and clutches 75 by

chain wheels

71 and 72. The dogs 77 actuate by means ofa magnet the clutches 75 which are fixedly mounted on the

shafts

73 and 74. The clutches 75 are thus connected through the driver elements 76 to the

chain wheels

71 and 72. When the

shafts

73 and 74 are thus rotated to a position at which the dogs 77 engage the driver elements 76, the dogs 77 thus disengage the driver elements 76 from the

chain wheels

71 and 72 and the sequence is then repeated. These movements of the

shafts

73 and 74 are transmitted over linkage 7 including an eccentric 7a to the pull-back shaft 16 and likewise to a shaft 22. The rotation of the shaft 22 effects a pivotal movement of the pressure rolls away from or toward the takeup rolls l0, and the rotation of the pull-back shaft 16 effects the prestressing of the takeup rolls 10.

The takeup rolls 10 are driven by springs 12 through chains 13 and carrier plates 14. The springs 12 tend constantly to turn the takeup rolls 10 in the takeup direction. With each reversal of the slide the springs 12 are prestressed over chains by the pull-back shaft 16. All the springs 12 are secured on a spring retaining bar 17. Their takeup force can be varied infinitely by displacing the spring retaining bar 17 by means of a threaded spindle 187 The takeup force as well as the pressure of all the rolls 10 can be varied only by adjusting the threaded spindles.

The hook takeup 40 is guided in guides 41 connected with the frame walls 4. It is subdivided into a takeup comb 42 and slide 43 (FIG. 5). The guides 41 are inclined to the vertical by a few degrees. The takeup comb 42 is formed of two hook bars 48 which consist each of a base rail 49 and counter rail 50 in which segments 51 are guided (FIG. 6). Into these segments are inserted hooks 52. The hooks 52 are bent in a right angle and so inserted into the segments 51 that their free ends point from the center in the direction of the knitting edge. Each hook 52 engages a number ofloops. Between the segments 51 and the base rails are interposed vertically arranged springs 53. The hooks 52 effect the takeup of the knitting immediately after the formation of the loops. The base rails 49 run on bearings (rollers) 54 mounted on the slides 43. The slides 43 have racks 44 which are connected with each other by a differential shaft 45 having gear wheels 46 arranged at its ends (FIG. 5). The vertical movement of the takeup comb 42 along the racks 44 is effected by a motor 37 through its output sprocket 37a, a chain 38 and a sprocket 61 (FIG. 1). The sprocket 61 is freely rotatably mounted on a shaft 62. When the chain wheel 61 is rotated, it couples over a carrier 63 with a clutch 64 and thus turns the shaft 62. A cam shaft 66 and the cams 39 arranged thereon (FIGS. 9a and 9b) are driven by the shaft 62 through a pair of gears 65. Each cam 39 engages one end of a respective lever 34 the other end of which engages a roller 47 mounted on a respective rack 44 and thus lifts or lowers the takeup comb 42 into the desired position.

For driving the hook takeup 30 in the horizontal direction, the hook bars 48 are provided with recesses which are engaged by carriers 56 which are mounted by means of nuts 57 on a threaded spindle 58 having an opposite thread (FIG. 5). The threaded spindle 58 is driven over a belt drive 59 by a motor 60. During the rotation of the threaded spindle 58 the carriers 56 move toward or away from each other, driving the hook bars 48.

If the knitting is to be taken up, the takeup comb 42 is lifted into its uppermost position before the first courses are started, the hooks 52 projecting over the needle beds 35. In order to make sure that the hooks 52 are at the same point each time a knitting is started, the extreme position of the hook bar 48 is limited'by permanent magnet stops 55 arranged on the slide 43 (FIG. 5). Due to the special design of the hooks 52 it is possible to place an intermediate mesh over the entire selected knitting width. Only at the points where the hooks 52 protrude through the needle beds do the needles 36 remain inactive. These inactive needles are taken up by the Jacquard device of the knitting machine. When the intermediate mesh is formed, the takeup comb 42 is lowered so far that the hooks 52 rest on the mesh rows. The knitting is taken up from the takeup comb 42 until the latter releases a limit switch arranged on the slide 43. After the actuation of this limit switch, the rolls of the roll takeup 5 are swung together by turning the pressure rolls 20 toward the stationary takeup rolls 10. The feed of the rolls is actuated immediately and the knitting is thus taken over smoothly by the rolls. Subsequently, the hooks 52 of the takeup comb 42 are moved in the direction of the knitting center by moving the hook bars 48 and the knitting is thus released. This movement of the takeup comb 42 takes place only in its bottom position. It remains in this position until a new knitting is started.

When the takeup rolls 10 are driven, they cooperate with the carrier plates 14. During the takeup of the knitting, the carrier plates 14 are turned clockwise by the springs 12 and drive the takeup rolls 10 through freewheeling rollers 19. When the springs 12 are tensioned during the reversal of the slide by the pull-back shaft 16, the carrier plates 14 are turned counterclockwise, the carrier plates 14 turning freely on the takeup rolls 10. Since the prestressed knitting tends to turn the takeup rolls 10 at this time counterclockwise and the pressure rolls 20 clockwise, the pressure rolls 20 are locked against such return rotation by the locking plates 27 which are positively coupled with the pressure rolls 20. These locking plates 27 act withrunning bolts 28 as a return lockv If another knitting with a wider head is to be taken up immediately, it is necessary to work a few intermediate courses so that, when the takeup comb 42 rises, the knitting is suspended on the needles of the front needle bed 35. When the takeup comb 42 rises, the pressure rolls 20 are turned away from the takeup rolls 10.

What is claimed is:

1. Fabric takeup mechanism for flat knitting machines for knitting fabrics of variable width, comprising a hook takeup including means carrying a row of hooks in a line parallel to the front edge of the fabric being knit, the hooks including a first set arranged on the left-hand side of the carrying means and a second set arranged on the right-hand side of the carrying means, the free end of each of the hooks of the first set pointing toward the left-hand edge of the fabric and the free end of each of the hooks of the second set pointing toward the right-hand edge of the fabric, means for bringing the row of hooks into engagement with the front edge of the fabric at the beginning of a knitting operation, a set of a plurality of coaxial takeup rolls and a set of a like plurality of coaxial pressure rolls each cooperating with a respective takeup roll to define a nip, the sets of rolls being positioned relative to the row of hooks to receive in the nips from the row of hooks the front edge of the fabric, and means for disengaging the row of hooks from the front edge of the fabric after the front edge of the fabric has been received in the nips.

2. Fabric takeup mechanism according to claim 1, in which the carrying means includes two bars, each having mounted thereon a respective one of the sets of hooks.

3. Fabric takeup mechanism according to claim 1, in which the means for engaging and disengaging the hooks includes means for raising and lowering the hook carrying means.

4. Fabric takeup mechanism according to claim 1, in which the means for engaging and disengaging the hooks includes means for reversibly driving the respective bars in mutually opposed directions.

5. Fabric takeup mechanism according to claim 1, further comprising means for adjustment of the takeup force of each of said takeup rolls and means for adjustment of the pressure of each of said pressure rolls.

6. Fabric takeup mechanism according to claim 5, in which said means for adjustment of the takeup force of each of said takeup rolls comprises means for driving the takeup roll including a first spring arranged for biasing of the takeup roll in the takeup direction and means for adjusting the tension of said first spring and said means for adjustment of the pressure of each of said pressure rolls comprises a second spring arranged for biasing of the pressure roll against the respective takeup roll and means for adjusting the tension of said second spring.

7. Fabric takeup mechanism according to claim 6, in which each takeup roll is provided with a carrier plate and freerunning rolls and each of the pressure rolls is provided with a locking plate and a running bolt together forming a return lock, and further comprising a first chain fastened at one end to the first spring and at the other end to the carrier plate, a pull-back shaft arranged to bias the carrier plates in the direction opposite the takeup direction of the takeup rolls, and a second chain fastened at one end to the pull-back shaft and at the other end to the carrier plate.

Claims

7. Fabric takeup mechanism according to claim 6, in which each takeup roll is provided with a carrier plate and free-running rolls and each of the pressure rolls is provided with a locking plate and a running bolt together forming a return lock, and further comprising a first chain fastened at one end to the first spring and at the other end to the carrier plate, a pull-back shaft arranged to bias the carrier plates in the direction opposite the takeup direction of the takeup rolls, and a second chain fastened at one end to the pull-back shaft and at the other end to the carrier plate.