GB2057020A

GB2057020A - Circular knitting machine

Info

Publication number: GB2057020A
Application number: GB7929047A
Authority: GB
Original assignee: NII PERERABOT ISKUSST VENNYKH
Current assignee: NII PERERABOT ISKUSST VENNYKH
Priority date: 1979-08-21
Filing date: 1979-08-21
Publication date: 1981-03-25
Also published as: DE2933851A1; DE2933851C2; GB2057020B

Abstract

A circular knitting machine comprises a frame 1, a needle carrier 3 with movable needles 7, warping reels 5 for feeding warp threads 6, a bobbin stand 4, mounted above said needle carrier and carrying bobbins for feeding stitch-forming threads 12, a drive 2, connected with the needle carrier 3 and/or the bobbin stand 4 for rotating them relative to each other, and also spring-actuated beams 8 mounted beneath the warping reels 5 each of which is kinematically connected with a driven half-coupling 18 of a friction clutch 16. The drive 2 is kinematically connected with a driving half-coupling 17 of said friction clutch 16. The driving half- coupling 17 is mounted for reciprocal movement relative to said driven half- coupling 18 under the action of the rocking beam 8. <IMAGE>

Description

SPECIFICATION Circular knitting machine This invention relates to circular knitting machines for making knitted fabrics with warp threads.

According to the invention, there is provided a circular knitting machine for making knitted fabrics with warp threads comprising a frame; a needle carrier with movable needles; a stand mounted beneath said needle carrier and carrying bobbins for feeding stitch-forming threads, the bobbins being arranged circumferentially above the needle carrier about the axis of the machine; a drive connected with the needle carrier and/or the stand for rotating them relative to each other; warping reels for feeding warp threads, said reels being mounted above the needle carrier and fixed stationary relative to said needle carrier; springactuated rocking beams, mounted beneath said warping reels; friction clutches, each of which is fixed stationary relative to said needle carrier and has a driving half-coupling kinematically connected with the drive and so mounted as to provide for reciprocal motion under the action of the rocking beam, and also a driven half-coupling kinematically connected with a warping reel for rotation and providing active feeding of the warp threads in case their tension changes and the rocking beam respectively rotates.

Because the warping reels are kinematically connected with the rotation drive and the engagement friction clutches, controlled by the rocking beams, it is possible to provide a uniform tension of the warp threads as they are drawn off from the warping reels and, therefore, to produce uniform knitted fabrics.

Structurally, a simple embodiment of the machine is an embodiment wherein a driven halfcoupling of each friction clutch has a worm meshed with a worm wheel mounted on the shaft of a respective warping reel for feeding the warp threads, while the rocking beam is connected with a driven half-coupling by means of a system of hinged levers and a screw pusher having a stop for the butt end of the driving half-coupling.

When utilizing hard threads for producing knitted fabrics, there is possible an alternative embodiment of the machine wherein the stop of the screw pusher is made in the form of a collar, and the surface of the butt end of the driving halfcoupling interacting therewith is perpendicular to the axis of the friction clutch.

When knitted fabrics are made of soft textured threads, it is expedient to employ a modification of the machine wherein the stop of the screw pusher is made in the form of a roller, and the surface of the butt end of the driving half-coupling interacting therewith in the form of a face cam.

With such an embodiment of the screw pusher and the driving half-coupling, the angle of rotation of the screw depends on the difference between the velocities of consuming and feeding the warp threads and on the diameter of the reels, while the force of engagement of the friction clutch is transmitted to the fillet of screw and not to the rocking beam, which considerabiy reduces nonuniformity of the warp thread tension within one cycle of an active feeding, thereby improving the quality of the fabric produced. In this case the function of the rocking beam is changed, consisting in preparing the friction clutch for engagement, while the engagement itself is caused by interaction between the roller of the screw stop and the axial cam of the driving halfcoupling.Rotation of the warping reel is of pulse character, the duration of the engagement pulse gradually increasing as the threads are being drawn off, having a minimum value at the beginning and a maximum value at the end of unreeling.

The invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic, perspective view of a first embodiment of a circular knitting machine according to the invention; Figure 2 shows a second embodiment of circular knitting machine according to the invention, with a rotating needle carrier and stationary bobbin stand; Figure 3 shows a third embodiment of circular knitting machine according to the invention, with a rotating needle carrier; Figure 4 shows a fourth embodiment of circular knitting machine according to the invention, with a rotating needle carrier and rotating bobbin stand; Figure 5 is a longitudinal section of a fifth embodiment of circular knitting machine according to the invention, with a driving halfcoupling having a bearing surface in the form of an axial cam;; Figure 6 is a longitudinal section through a six embodiment; Figure 7 is a graph illustrating changes in time of the angular velocity of the circular knitting machine having driving clutches with flat bearing butt ends; Figure 8 is a graph illustrating changes in time of the angular velocity of a warping reel at the beginning of unreeling, in the embodiment of the circular knitting machine shown in Figure 5 of the drawings; Figure 9 is a graph illustrating changes in time of the angular velocity of a warping reel at the end of unreeling, in the embodiment of the circular knitting machine shown in Figure 5 of the drawing.

A circular knitting machine for making knitted fabrics with warp threads, as can be seen in Figure 1, comprises a frame 1 on which is mounted a drive motor 2, a needle carrier 3, a stand 4, and also warping reels 5 for feeding warp threads 6.

The needle carrier 3, as is typical of circular knitting machines, is made in the form of a rotating body of revolution having a plurality of movable needles 7. The needle carrier 3 can also be made in the form of a disc with radially movable needles 7, or in the form of a cylinder with axially movable needles 7. As the operation principie remains the same for all the embodiments of the circular knitting machines, there will now be described a machine having the needle carrier 3 made in the form of a cylinder.

The warping reels 5 are so mounted as to enable them to rotate above said needle carrier 3, while their axes are fixed stationary relative to said needle carrier. Beneath each of the warping reels 5, there is mounted a rocking beam 8 the slewing axis of which is stationary relative to the warping reel 5. The warp threads 6 are passed round the rocking beams 8 which are intended for guiding said threads to the needle carrier 3. The rocking beam 8 is loaded by a spring 9.The stand 4 is mounted above said needle carrier 3 and carries bobbins 11, mounted on brackets 10, for feeding stitch-forming threads 12, and bobbins 14, mounted on brackets 13, for feeding weft threads 1 5. As can be seen in Figure 1, the bobbins 11 for feeding the stitch-forming threads 12 are arranged circumferentially about axis 0-0 of the machine and above the needle carrier 3.

Each warping reel 5 is drivingly connected with the drive 2 through a friction clutch 1 6 to provide for actively feeding the warp threads 6 as they are knitted into the fabric. Each friction clutch 1 6 comprises a driving half-coupling 1 7 and a driven half-coupling 1 8. The driven half-coupling 1 8 is connected with the warping reel 5 through a worm 19 loaded by a spring 20, and through a worm wheel 21 fixed on a shaft 22 of said warping reel 5.

The driving half-coupling 17 is connected with the drive 2 by means of a shaft 23 carrying on its lower end a pinion 24 meshed with a ring pinion 25. The ring pinion 25 has an inner geared ring 26 and an outer geared ring 27. The pinion 24 is meshed with the inner geared ring 26 of the ring pinion 25. Meshed with the outer geared ring 27 of the ring pinion 25 is a pinion 28 mounted together with a pinion 30 on a shaft 29. The pinion 30 is meshed with a pinion 31 mounted coaxially with the needle carrier 3. By means of a system 32 of pinions, the pinion 31 is drivingly connected with the drive 2.

The driving half-coupling 1 7 of the friction clutch 16 is mounted on the shaft 23 so as to ensure its axial reciprocation under the action of the rocking beam 8 which, through a system of hinged levers 33, is connected with a screw pusher 34 of said driving half-coupling 17.

Beneath the needle carrier 3 there are mounted rollers 35 for guiding the fabric produced. Said rollers 35 are mounted stationary relative to the needle carrier 3.

The drive 2 is intended for transmitting relative rotary motion to the needle carrier 3 and the stand 4.

In the embodiment shown in Figure 2, the needle carrier 3 with movable needles 7 is mounted for rotation and is drivingly connected with the drive motor 2. The needle carrier 3 is fixed to the pinion 31, and the warping reels 5, the friction clutches 1 6 and the spring-actuated rocking beams 8 are mounted on a rotary table 36 having a geared rim.

The geared rim of said rotary table 36 is meshed with a pinion 37 mounted on an extension of the shaft 29. In this embodiment, the stand 4 is fixed stationary on the frame 1 above the needle carrier 3.

In the embodiment of Figure 3, the needle carrier 3 with the movable needles 7 is fixed stationary on the frame 1, while the stand 4 is mounted for rotation.

In this embodiment there is a geared ring on the inner side of the ring stand 4 meshed with a pinion 38 mounted on the extension of the shaft 29.

The table 36, with the warping reels 5, the rocking beams 8 and the friction clutches 16, is fixed stationary on the frame 1 of the knitting machine.

In the embodiment of Figure 4, the needle carrier 3 and the stand 4 are mounted for rotation and are drivingly connected with the drive motor 2. In this embodiment, the needle carrier 3 is fixed stationary on the pinion 31, and the geared ring of the stand 4 is meshed with the pinion 38 mounted on the extension of the shaft 29, the stand 4 and the needle carrier 3 rotating in the same direction but at different angular velocities.

In a further possible embodiment (not shown in the drawings), an idie pinion is inserted between the pinion 38 and the geared ring of the stand 4.

In this case, the stand 4 and the needle carrier 3 rotate in opposite directions.

In each of the above described embodiments, the rollers 35 for guiding the fabric produced are mounted stationary relative to the needle carrier 3.

Figure 5 shows in greater detail the construction of the friction clutch 1 6, the screw pusher 34 and the driving connection between the warping reel 5 and the drive motor 2. As can be seen in this figure, the driving half-coupling 1 7 is movably mounted on the shaft 23 and prevented from rotating by a key 39 inserted in a longitudinal slot of said driving half-coupling 1 7. The driven half-coupling 1 8 with the worm 19 is movably mounted on the shaft 23.

The screw pusher 34 comprises a screw 40 made in the form of a hollow cylinder having male multiple thread and a nut 41. In its upper part, the nut 41 has a collar 42 upon which rests the driven half-coupling 1 8.

The spring-actuated rocking beam 8, through the system of levers 33, is connected with a radial lever 43 (refer to Figure 1) mounted on the screw 40 (Figure 5).

Two modifications of the screw pusher 34 and the friction clutch 1 6 will be described.

According to the first modification, shown in Figure 5, a bearing butt end 44 of the driving halfcoupling 17 is flat and arranged on the axis of the friction clutch 1 6. The screw 40 has a stop on its inner side made in the form of a collar 45 interacting with the bearing butt end 44 of the driving half-coupling 1 7.

According to another modification, shown in Figure 6, a stop of the screw pusher 34 is made in the form of a roller 46 mounted on a shaft 47. The bearing butt end 44 of the driving half-coupling 17 is made in the form of an axial cam. Structurally, a simpie embodiment of the axial cam is an embodiment wherein a flat butt end of the driving half-coupling 1 7 forms an acute angle with the axis of the friction clutch 1 6.

The aforedescribed circular knitting machine operates in the following manner. After the warping reels 5 are charged, the warp threads 6 are passed over the rocking beams 8 and distributed among the needles 7 of the needle carrier 3.

The stich-forming threads 1 2 and the weft threads 1 5 are guided to respective needles 7.

After the needles are threaded, the drive motor 2 is started to transmit relative rotary motion to the needle carrier 3 and the stand 4. Simultaneously, through the system 32 of pinions, the pinion 31 is set in motion, and, through the pinion 30 and 28, rotation is transmitted to the ring pinion 25. With the ring pinion 25 rotating' the pinion 24, interacting with the inner geared ring 26 of the pinion 25, also rotates, and, consequently, the shaft 23 with the driving half-coupling 1 7 rotates too.

Under the action of the spring 20 and due to the tension of the warp threads 6, the driven halfcoupling 1 8 is pressed against the collar 42 of the screw 41. This is why the driven half-coupling 18, the worm 19, the worm wheel 21 and the warping reels 5 remain immovable relative to one another when the shaft 29 rotates.

As the warp threads are being knitted into the fabric, the rocking beam 8 rotates, overcoming resistance of the spring 9. When the beam 8 rotates, a respective system of the levers 33 rotates the screw 40. The screw 40 goes up the screw thread of the nut 41 , whereas its stop interacting with the bearing butt end 44 of the driving half-coupling 17, lifts said driving halfcoupling 17. Interacting with the driven halfcoupling 18, the driving half-coupling 17 slightly lifts said driven half-coupling 1 8 over the collar 42 of the nut 41. Rotation is transmitted from the driving half-coupling 17 to the driven halfcoupling 18, and, through the worm 19 and the worm wheel 21 , to respective warping reel 5, the warp threads 6 being actively fed to the needle carrier 3.

After unreeling a necessary length of the warp threads 6, the beam 8, compensating for the difference between the fed length and the consumed length of the threads, returns to its initial position under the action of the spring 9.

The system of levers 33 turns the screw 40 which sinks with the driving half-coupling 1 7. The driving half-coupling 1 7 is released from engagement with the driven half-coupling 1 8. After being lowered on the collar 42 of the nut 41, the driven half-coupiing 1 8 is braked and rotation of the warping reel 5 stops. As the warp threads 6 are being knitted in, the cycles of active feeding repeat themselves in a similar manner.

In steady-state conditions, the rocking beam 8 and the screw 40 take a position providing for an automatic change in the average rotational velocity of each warping reel 5, and for maintaining a constant average linear velocity of unreeling the warp threads 6; the tension of the threads remains constant and depends on the force of compression of the spring 9.

In the embodiment of the knitted machine shown in Figure 2, rotation of the pinion 31 is accompanied by rotation of the needle carrier 3, the rotary table 36 with the warping reels 5, the rocking beams 8 and the friction clutches 1 6. The rollers 35 rotate synchronously with the needle carrier 3, while the stand 4 remains immovable.

During the operation of the embodiment of the knitting machine shown in Figure 3, rotation is transmitted from the drive motor 2 to the stand 4 through the pinions 32, the pinidn 31, the shaft 29 and the pinion 38; at the same time, the needle carrer 3 and the table 36 with the warping reels 5, the rocking beams 8 and the friction clutches 1 6 remain immovable. In this rotation is transmitted to the shaft 23 through the ring pinion 25.

During the operation of the embodiment of the knitting machine shown in Figure 4, rotation is transmitted from the drive motor 2 both to the needle carrier 3 and the stand 4.

During the operation of the embodiment of the machine shown in Figure 5, as the warp threads 6 are being knitted in, the beam 8, turning through the system of the levers 33, transmits motion to the screw 40 which, in turn, rises and engages recurrently the friction clutch 1 6. Angular velocity zD of the warping reel 5 changes in time t, as shown by the graph in Figure 7. As can be seen in this graph, duration of the cycles of actively feeding the warp threads 6 is of random character and subject to considerable changes.

During the operation of the embodiment of the machine shown in Figure 6, the axial cam of the driving half-coupling 17, turning around the roller 46, alternately engages and disengages the friction clutch 1 6. The cycles of operation of the mechanism are repeated at a frequency determined by the rotational velocity of the shaft 23. Thus, rotation of the warping reel 5 is of pulse character. The frequency and amplitude of the pulses of turning of the warping reel 5 remains constant, while duration of the pulses changes, depending on the diameter of reeling and the velocity of consuming the warp threads 6.

As the diameter of the reels changes, the period of time during which the friction clutch 11 is engaged automatically increases, as can be seen in Figure 8 and Figure 9 representing graphs illustrating changes with time t of the angular velocity w of the warping reel 5 at the beginning and at the end of the unreeling process.

Thus, the aforedescribed structural peculiarities of a circular knitting machine make it possible to stabilize the tension of the warp threads and to bring to conformity their feeding and the velocity of their knitting into the fabric.

This factor favourably affects the quality of the knitted fabric produced.

Claims

1. A circular knitting machine for making knitted fabrics with warp threads, comprising a frame; a needle carrier with movable needles; a bobbin stand mounted above said needle carrier and carrying bobbins for feeding stitch-forming threads, the bobbins being arranged above said needle carrier circumferentially about the axis of the machine; a drive connected with the needle carrier and/or the bobbin stand for rotating them relative to each other; warping reels for feeding warp threads, so mounted so as to enable them to rotate above the needle carrier and to be stationary relative to said needle carrier; springactuated rocking beams mounted beneath said warping reels; friction clutches, each of which is fixed stationary relative to said needle carrier and has a driving half-coupling kinematically connected with the rotation drive and mounted for reciprocal movement under the action of the rocking beam, and also a driven half-coupling kinematically connected with each warping reel for rotating and actively feeding the warp threads when their tension changes and the rocking beam turns.

2. A circular knitting machine, as claimed in claim 1, wherein the driving half-coupling of each said friction clutch has a worm meshed with a worm wheel mounted on the axis of the respective warping reel for feeding the warp threads, and the rocking beam is connected with said driving halfcoupling by means of a system of hinged levers and a screw pusher, having a stop for the butt end of said driving half-coupling.

3. A circular knitting machine, as claimed in claim 2, wherein the stop of said screw pusher is made in the form of a collar, and the surface of the bearing butt end of said driving half-coupling interacting with the screw pusher is perpendicular to the axis of said friction clutch.

4. A circular knitting machine, as claimed in claim 2, wherein the stop of said screw pusher is made in the form of a roller, and the surface of the bearing butt end of said driving half-coupling interacting with the screw pusher is made in the form of an axial cam.

5. A circular knitting machine substantially as herein described with reference to and as illustrated in the accompanying drawings.