US3850012A

US3850012A - Circular knitting machine comprising a fabric draw off device

Info

Publication number: US3850012A
Application number: US00289881A
Authority: US
Inventors: N Bourgeois
Original assignee: Etudes et Bonneterie SA
Current assignee: Etudes et Bonneterie SA
Priority date: 1971-11-09
Filing date: 1972-09-18
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26
Also published as: DE2243054B2; CH539156A; FR2159873A5; JPS4856949A; IT972373B; DE2243054A1; GB1394097A; DE2243054C3

Abstract

A circular knitting machine comprises a fabric draw off device rotating with a rotary knitting assembly, said device including diametral traction rollers about which the knitted fabric is driven tangentially. The traction rollers are positively driven by a mechanical transmission device including a gear box with an input pinion driven by a rotary crown of said assembly, two exchangeable gears, and an output pinion the speed of which can be varied, as a function of the length of the fabric produced per turn of the machine, by choice of said exchangeable gears.

Description

United States Patent Bourgeois 1 1 Nov. 26, 1974 [5 CIRCULAR KNITTING MACHINE 463,788 11/1891 Hose et al 66/151 COMPRISING A FABRIC DRAW on: 3,415,081 12/1968 Anderson 66/151 DEVICE Prima Examiner-W. C. Re nolds l l W Y [75] nventor lglpg'rllicegt Pau Bourgeois Troyes Assistant Examiner /& M. Falik Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [73] Assignee: Etudes et Bonneterie S.A.,

Lausanne, Switzerland [22] Filed: Sept. 18, 1972 [57] ABSTRACT A circular knitting machine comprises a fabric draw [21] Appl 289881 off device rotating with a rotary knitting assembly, said device including diametral traction rollers about [30] Foreign Application Priority Data which the knitted fabric is driven tangentially. The Nov. 9, 1971 Switzerland 16270/71 traction rollers are Positively driven y a mechanical transmission device including a gear box with an input 52 U.S. c1. 66/151 pinion driven y a rotary Crown of Said assembly, two [51] Int. Cl D04b 15/88 exchangeable gears, andan Output Pinion the Speed of 58 Field 61 Search 66/149 R, 151, 153 which can be varied, as a function of the length of the fabric produced per turn of the machine, by choice of 5 R f en e Cited said exchangeable gears.

UNITED STATES PATENTS Bradford 66/151 4 Claims, 4 Drawing Figures PATENTE; W26 1974 3,850,012

sum 1 er a PAIEN'IL33265374 3 850,012

SHEH 2 OF 3 26 I Fig. 2

PATEMTE Elm/261974 SHEET 3 UP 3 CIRCULAR KNITTING MACHINE COMPRISING A FABRIC DRAW OFF DEVICE The invention relates to circular knitting machines of the type comprising a rotary assembly including at least one needle bed and a fabric draw off device rotating with said assembly, said draw off device including at least one traction roller disposed in a diametral plane of the machine and upon which the knitted fabric is driven tangentially.

On circular knitting machines it is known to use a rotary fabric draw off device driven in synchronism with the elements carrying the knitting members, the draw off device generally comprising several traction rollers disposed parallel to one another and generally diametrally of the machine. These rollers are rotatably mounted on the draw off device and a tube of fabric formed by the knitting members engages between the rollers in the form of a rectilinear sheet of doubled thickness which is driven tangentially about the rollers and is then, in most cases, rolled flat on a rotating shaft of a winding mechanism. The part of the mechanism controlling the rotation of the traction rollers is also provided with adjustment means enabling modification of the speed of the traction rollers as a function of the rate of production of the fabric on the knitting members.

In most known machines of this type, rotation of the traction rollers results from the relative movement between the assembly of the draw off device and the stationary parts of the machine.

In certain cases, a friction device is mounted on the rotary draw off device, this friction device being adjustable to allow modification of the speed of rotation of the traction rollers. The transmission includes a driving element which is controlled, during rotation of the rotary assembly of the machine, by a stationary toothed crown, and a driven element which is connected by gears to the rollers to be controlled, the friction device being adjusted by the movement of a counterweight.

Because of the conception of such mechanisms, a sliding is produced between the various element of the friction device and thus does not enable the fabric to be driven at a constant speed by the traction rollers.

In another type of known mechanism, two ratchet wheels with blocking rollers are mounted opposite one another at the ends of one of the traction rollers and are urged, during rotation of the rotary assembly, by arms which move on an inclined stationary camforming ring the inclination of which is adjustable to enable setting of the speed of rotation of the roller.

Since for this type of mechanism the two ratchet wheels with blocking rollers operate alternately, the traction roller is rotated intermittently and its rotation is, moreover, not constant for all positions of the rotary draw off device in relation to the inclined control ring. The consequence of this drawback is particularly emphasized in large-output multisystem machines where the length of knitted fabric produced per turn of the machine is relatively great.

Another disadvantage common to these different types of mechanism resides in the difficulty of obtaining a given adjustment of the speed of traction of the fabric, since in effect it is difficult for the operator to return with high precision to a previous setting.

The present invention aims to remedy these disadvantages and to provide the traction roller(s) with a continuous rotation, ie which does not involve the problems inherent when the rotation is intermittent, and with a speed exactly proportional to that of the rotary assembly of the machine, independent of the speed of rotation of the traction roller(s), whatever may be the position occupied by the rotary draw off device relative to the main frame of the machine.

According to the invention, a circular knitting machine comprises a rotary assembly including at least one needle bed and a fabric draw off device rotating with said assembly, said traction device including at least one traction roller disposed generally diametrally of the machine and upon which roller the knitted fabric is driven tangentially, mechanical means forming an uninterrupted kinematic chain for positively driving the traction roller(s) from a driving element rotatably driven by another element rotating in synchronism with said assembly and draw off device, and means for enabling the speed of the driving element to be adapted as a function of the length of fabric produced per turn of the machine.

The accompanying drawings show, by way of example, an embodiment of the invention as well as a variation. In the drawings:

FIG. 1 is a perspective view of the lower part of a circular knitting machine schematically showing the fabric draw off device as well as a control mechanism for the traction rollers;

FIG. 2 is a perspective view of a part of the control mechanism of FIG. 1;

FIG. 3 is a cross-section taken along line X-X of FIG. 2; and

FIG. 4 is a view similar to FIG. I showing a varied form of control mechanism.

The circular knitting machine partially shown in FIG. 1 comprises a rotary assembly provided with one or two needle beds (not shown) and a device 1 for drawing down and winding of fabric produced by the needles. This draw off device 1 includes at its upper part three

traction rollers

2, 3, 4 disposed parallel to one another, generally diametrally of the machine, in a plane perpendicular to the axis of rotation of said assembly. Said draw off device I is fixed on a rotary toothed crown 5 coaxial to the rotary assembly and disposed at the base of a stationary frame 6 of the machine, the crown and the rotary assembly being rotated at the same speed driving means, not shown. The traction rollers could also be disposed diametrally but at different levels.

The fabric produced forms a tube 7 which engages, in the form of a rectilinear sheet of double thickness, between the roller 2 and the central roller 3 about which it passes and then engages between this central roller 3 and roller 4, from where it is wound on a rotating shaft 8 of a winding mechanism of a type well known to these skilled in the art, the details and mode of control of which do not fall within the ambit of the invention and are therefore not shown.

Traction of the fabric by the

rollers

2, 3, 4 takes place tangentially, and the rotation of the three rollers is controlled from rotation of the draw off device with said rotary assembly by means of the following elements which form a differential in a kinematic chain with positive drive comprising a transmission with differential movement.

A gear train 9 carried by a support integral with stationary frame 6 comprises a driving pinion ll meshing with the teeth of the rotary crown 5. Pinion 11 is coaxially connected to a second pinion 12 driving, by means of an intermediary pinion 13, a pinion 14 of a pair of coaxial

integral pinions

14, 15. Pinion 15 meshes with a pinion 16 on the shaft of which is keyed a chainwheel 17.

Chainwheel 17 is connected by a chain 18 to a chain- 1 wheel 19 of a pair of

chainwheels

19, 20 joined by a sleeve 39 passing through the base of device 1, which sleeve is mounted about a central spindle, not shown, integral with the base of frame 6 and disposed coaxial with said crown and said rotary assembly. Chainwheel 20 is connected by a chain 21 to a chainwheel 22 keyed on the lower end of a vertical shaft 23 supported by the rotary draw off device. The upper end of shaft 23 carries a worm 24 engaging with a worm wheel 25 mounted at one end of traction roller 4, the rotation of

rollers

2 and 3 being provided from roller 4 by gears not shown.

As will be described in detail further on, pinions l2 and 14 of gear train 9 are removably mounted on their shafts and can be exchanged for pinions with different numbers of teeth. Taking into account the ratios defined by the other gears and toothed wheels of the mechanism, it is is possible, by a judicious combination of

pinions

12 and 14, to obtain a large range of rotational speeds for the traction rollers.

The different elements of-the described drive mechanism thus constitute an uninterrupted kinematic chain enabling the device to obtain, by a positive liason, a rotational speed of the traction rollers exactly proportional to that of the rotary assembly of the machine, whatever be the value of this speed.

Other advantages of the described machine, and particularly those resulting from the use of a crown wheel and a pair of sprocket wheels, coaxial to the crown wheel, constituting with the gear train, a transmission with differential, movement will be apparent from the following explanation analysing the functional relationships between the various members of the control mechanism. For the purpose of simplification, the reference numbers of various members, are replaced by letters. Hence, the toothed crown 5, driving pinion 11,

gears

12, 14, l5, l6 and 17 are respectively designated by A, B, C, D, E, F and G;

double chainwheels

19, 20 and wheel 22 by H, J and K; the ratio between worm 24 and worm wheel 25 of the traction roller is designated by l/R; and the diameter of roller 4 by d. The expression turn of the machine means each rotation of the rotary assembly. i.e., ofthe elements carrying the knitting members.

For each turn of the machine, toothed crown 5 and the assembly of the draw off device including chainwheel 22, the worm gear 24, wheel 25 and the traction rollers also make one turn about the central axis of the machine. The length l of fabric tangentially driven by the traction rollers during one turn of the machine is given by the following formula:

l=(A/B 'C/D'E/F'G/H l) 'J/K l/R'n'd,

the part J/K l/R 1r (1 of which may be expressed by k, a constant characteristic of the various members of the rotary draw off device.

The number n of turns of the double chainwheels H and J in the same direction of rotation as toothed crown A, per turn of the latter, i.e., for one turn of the machine, is expressed by:

n =A/B C/D E/F G/H this number of turns being dependant on the ratio A/B,

' defined by the pair of exchangeable pinions (C, D) of gear train 9.

The length of fabric driven tangentially by the traction rollers for one turn of the machine is thus given by Selection of the ratio A/B by choice of the interchangeable pinions C, D would enable the provision of n l, in which case the

rollers

2, 3 and 4 would not turn about their axes and the traction of the rollers on the fabric is therefore zero.

By employing a transmission having a differential movement, the means for enabling adaptation of the speed of the driving element F as a function of the length of fabric produced per turn of the machine may be disposed on a stationary part of the machine. It thus becomes possible, from small variations in the gear ratios of the gear train 9, to obtain large variations in the speed of rotation of the traction rollers, this rotation being moreover exactly uniform even at very low speed.

The disposition and the features of the gear train 9 enable the provision of a simple gear box, of low bulk and with easy access. An embodiment of such a gear box, in accordance with the mechanism of FIG. 1, is shown in detail on FIGS. 2 and 3.

A support 10, fixed on the stationary frame 6 and carrying the gear train 9, has the form of a case provided with a cover 26 pivoting about a pin 27. The input pinion 11, which meshes with crown 5, as well as reducing pinion 15 are disposed under the base of support 10 and are respectively fixed on

shafts

28, 29 which pass through the base of support 10 to control the corresponding

interchangeable pinions

12 and 14 mounted so as to be axially removable on fluted ends of the respective shafts. The second reducing pinion l6 and chainwheel 17 constitute an assembly rotatably mounted on a shaft 30 fixed below support 10.

The intermediary pinion l3, rotatably connecting the removable pinions l2 and 14, is freely rotatably mounted on a shaft 31. To facilitate exchange of

pinions

12 and 14 of different diameters, no fixing means for shaft 31 are provided, but shaft 31 is simply held at its ends by jamming between the plane surface 32, defining the upper surface of the base of support 10, and the pivoting cover 26 which is folded down and held by a locking screw 33. So as to eliminate any risks of unwanted displacement of the pinion 13 during manipulation of the cover 26, a permanent magnet 34 is disposed at the base of shaft 31 and ensures a slight holding thereof on the surface 32.

Such an arrangement considerably facilitates the exchange of the various removable pinions l2 and 14, which may additionally include visual identification means such as letters or numbers enabling a desired rotational speed of the traction rollers to be rapidly obtained.

Each time that it is necessary to modify the speed of the traction rollers, clamping of the

interchangeable pinions

12, 14 produces a momentary interruption in the kinematic chain connecting the crown 5 to the rollers. The fabric 7, submitted to a certain tension between the knitting members and the rollers, tends to free itself by reversing the direction of rotation of the latter; the use of a worm gear with suitably inclined worm 24 (FIG. 1) enables such a reversal to be prevented.

In the variation shown in FIG. 4, the differential movement is obtained by a second toothed crown 35 concentric to the control crown 5 and rotatably mounted thereon. Crown 35 is controlled by a driving pinion 36 disposed at the output of the gear box 37 of which the input pinion 40 meshes with the crown 5, and driving of shaft 23 of the draw off device is effected from rotation of crown 35 by means of pinion 38.

What is claimed is:

1. A circular knitting machine having a stationary frame and comprising:

a rotary assembly mounted on said stationary frame;

a fabric draw-off device mounted on said rotary assembly and rotating therewith, said drawoff device comprised of at least one knitting traction roller operatively disposed substantially diametrically of said rotary assembly, knitted fabric being tangentially driven thereon; and

mechanical transmission means operatively coupled between said rotary assembly and said at least one knitting traction roller and forming an uninterrupted kinematic chain for positively driving said at least one traction roller, said mechanical transmission means comprised of a first rotary command element coaxially connected to said draw off device, and rotating therewith, a second rotary command element coaxial to said first rotary command element, means connected to said second command element and said at least one traction roller for transmitting rotation from said second command element to said at least one traction roller and gear box means positioned on said stationary frame of the rotary knitting machine and coupled to both said first and second rotary command elements for controlling said second rotary command element from the movement of said first rotary command element, said gear box means comprised of at least one pinion said at least one pinion being removably mounted there in and being interchangeable with a pinion of a different diameter to vary the rotative speed of said second command element.

2. The circular knitting machine of claim 1 wherein said first rotary command element is a crowned wheel, said second rotary command element being comprised of a pair of coaxial chain wheels coupled together for rotation and wherein said gear box means further comprises a first chain wheel and a first chain, said chain being linked to said first chainwheel and one of said pair of coaxially coupled chainwheels, and said means transmitting the rotation to said at least one traction roller from said second rotary command element being comprised of a second chainwheel placed on an end of a shaft supported by said drawoff device and having gear means at the other end thereof, the rotation of said second chainwheel being transmitted to said at least one traction roller through said gear means which is operatively positioned therefor, and a second chain linking said second chain wheel to the other of said pair of coaxial coupled chainwheels.

3. A circular knitting machine according to claim 1 wherein said first rotary command element is a first crown wheel and said second rotary command element is a second crown wheel coaxial to said first crown wheel, said gear box means comprises a first pinion coupled to said second crown wheel, and said means for transmitting rotation to said at least one traction roller from said second rotary command element being comprised of a second pinion coupled to said second crown wheel and a shaft having one end adjacent said at least one traction roller and supported by said drawoff device and having gear means on said adjacent end operatively coupled to said at least one traction roller, said second pinion being coupled to the opposite end of said shaft.

4. A circular kitting machine as recited in claim 1., wherein said gear box means comprises two interchangeable pinions and a third intermediate pinion rotatably connecting said two interchangeable pinions, said intermediate pinion freely fitted on a shaft, and locking means comprised of a fixed member and a movable member, said shaft of said intermediate pinion being rigidly supported between said fixed and movable members at a position within said gear box means de pending on the diameters of the interchangeable pin-

Claims

1. A circular knitting machine having a stationary frame and comprising: a rotary assembly mounted on said stationary frame; a fabric draw-off device mounted on said rotary assembly and rotating therewith, said drawoff device comprised of at least one knitting traction roller operatively disposed substantially diametrically of said rotary assembly, knitted fabric being tangentially driven thereon; and mechanical transmission means operatively coupled between said rotary assembly and said at least one knitting traction roller and forming an uninterrupted kinematic chain for positively driving said at least one traction roller, said mechanical transmission means comprised of a first rotary command element coaxially connected to said draw off device, and rotating therewith, a second rotary command element coaxial to said first rotary command element, means connected to said second command element and said at least oNe traction roller for transmitting rotation from said second command element to said at least one traction roller and gear box means positioned on said stationary frame of the rotary knitting machine and coupled to both said first and second rotary command elements for controlling said second rotary command element from the movement of said first rotary command element, said gear box means comprised of at least one pinion, said at least one pinion being removably mounted there in and being interchangeable with a pinion of a different diameter to vary the rotative speed of said second command element.

3. A circular knitting machine according to claim 1 wherein said first rotary command element is a first crown wheel and said second rotary command element is a second crown wheel coaxial to said first crown wheel, said gear box means comprises a first pinion coupled to said second crown wheel, and said means for transmitting rotation to said at least one traction roller from said second rotary command element being comprised of a second pinion coupled to said second crown wheel and a shaft having one end adjacent said at least one traction roller and supported by said draw-off device and having gear-means on said adjacent end operatively coupled to said at least one traction roller, said second pinion being coupled to the opposite end of said shaft.

4. A circular kitting machine as recited in claim 1, wherein said gear box means comprises two interchangeable pinions and a third intermediate pinion rotatably connecting said two interchangeable pinions, said intermediate pinion freely fitted on a shaft, and locking means comprised of a fixed member and a movable member, said shaft of said intermediate pinion being rigidly supported between said fixed and movable members at a position within said gear box means depending on the diameters of the interchangeable pinions.