Claims
- 1. A control system for a circular knitting machine the control system including a main drive shaft, and means for varying the rate at which yarn is supplied to the machine in a controlled manner over a period of time such that the shape of the workpiece is controlled by the rate of yarn feed, said means for varying the rate at which yarn is supplied to the machine including a rotatable profile cam, and a variable speed pulley fixed on said main drive shaft for rotation therewith, and wherein said rotatable profile cam acts in a direct linear manner upon said variable speed pulley to control the yarn feed supply rate.
- 2. A control system for a circular knitting machine as claimed in claim 1 in which the controlled yarn is a single feed of elastic yarn.
- 3. A control system for a circular knitting machine as claimed in claim 1 in which the controlled yarn is a ground yarn.
- 4. A control system for a circular knitting machine as claimed in claim 1 in which a plurality of yarn feeds are controlled either elastic or non-elastic/ground yarns.
- 5. A control system for a circular knitting machine as claimed in claim 1 including an electric motor drivingly connected to said rotatable profile cam, and an electronic control system to supply control signals to said electric motor to control the yarn feed supply rate.
- 6. A control system for a circular knitting machine as claimed in claim 1 in which the rotational speed of said profile cam is varied relative to the main drive speed to produce a different shape of workpiece.
- 7. A control system for a circular knitting machine as claimed in claim 1 in which said variable speed pulley is driven from said main drive shaft such that the yarn feed is driven at a variable speed which is a ratio of the main drive speed of the knitting machine.
- 8. A control system for a circular knitting machine as claimed in claim 1 in which the knitting machine is of the dial and cylinder type and in which a control system is provided for the dial and cylinder machine and includes means for adjusting the dial height by further adjustment means in addition to the feed yarns.
- 9. A control system for a circular knitting machine as claimed in claim 1 including means for collecting the completed workpieces, said means comprising rotary collection roller means rotating at the speed of rotation of the dial and cylinder.
- 10. A control system for a circular knitting machine as claimed in claim 9 including means for marking the beginning of each workpiece produced.
Parent Case Info
This is a continuation-in-part of application Ser. No. 07/094,338, filed Sept. 8, 1987 now abandoned.
The present invention relates to knitting machines and more particularly to circular knitting machines which are used to knit tubular workpieces.
Circular knitting machines are well known and a common type comprises two main knitting components to produce a tubular workpiece. The components known as a dial and cylinder cooperate together to produce a tubular workpiece, the dial being manually adjustable when the machine is stationary to adjust the stitch length and hence the width of the tubular workpiece within the practical limits set by the size of the machine. The operation of a circular knitting machine is extremely well known within the knitting machine art and does not form part of the present invention. Such operation will be referred to but will not be described in any detail because of its common knowledge within the knitting machine art.
The simple dial and cylinder machine thus produces a parallel tubular workpiece the width of which can be adjusted when the machine is stationary by adjustment of the dial height. The simple machine is, therefore, not capable of producing a shaped tubular workpiece, i.e., one which varies in diameter along its length.
A particular, but not exclusive use of circular type knitting machines is in the manufacture of elastic bandages in which one of the yarns used is elastic, the yarn being knitted or laid in round the circumference of the tube to provide an elasticated bandage.
In a known machine a complex single feed elastic lay-in system is used which directly controls the feed of the elastic yarn. By such control a shaped workpiece, for example to fit a knee, can be produced, the elastic yarn serving to shape the workpiece.
A further known machine is the single cylinder stocking machine which is used to manufacture shaped stockings. This type of machine is provided with a drum/cam control system. The machine can knit a limited graduated shape, e.g. a stocking shape by a combination of the control drum segments and by a graduated lowering of the cylinder during knitting using a rack wheel, cam and chain studs. The machine is, however, relatively non-versatile in that the shape to be knitted is not readily alterable and the machine cannot control the multi-feed of elastic and ground yarns.
The present invention provides a control system for a knitting machine which enables the machine to produce a variable width workpiece of desired shape which control system is versatile in use and which is capable by simple changes of altering the shape produced by the machine.
The present invention, therefore, provides a control system for a circular knitting machine, the control system including means for varying the rate at which yarn is supplied to the machine in a controlled manner over a period of time such that the shape of the workpiece is controlled by the rate of yarn feed.
Preferably in a first embodiment the controlled yarn is a single feed of elastic yarn. In an alternative embodiment the controlled yarn is a ground yarn.
In an alternative embodiment many yarn feeds may be controlled either elastic or non-elastic or ground yarns.
Preferably the means for varying the rate at which yarn is supplied to the machine is by means of a profile cam which is rotated to act in a direct linear manner on a variable speed pulley to control the yarn feed supply rate. In a particular embodiment the rotational speed of the profile cam is varied relative to the main drive speed to produce a different shape of workpiece.
Preferably the variable speed pulley is driven from the main drive supply such that the yarn feed is driven at a variable speed which is a ratio of the main drive speed of the knitting machine.
In a further embodiment in addition to controlling the elastic yarn the ground yarn is controlled at a different rate to the elastic yarn. In a more complex control system for a dial and cylinder machine the dial height may also be adjusted by further adjustment means in addition to the feed yarns during knitting. Thus the width of a workpiece may be adjusted in a variable manner to produce a variable width garment.
The present invention also provides a method of producing a variable width garment on a circular dial and cylinder knitting machine by adjusting the dial height of the machine while the machine is running. Additionally, the feed rate of an elastic yarn may also be adjusted at the same or a different rate to the dial adjustment thereby producing a garment of wide width variation.
US Referenced Citations (7)
Foreign Referenced Citations (3)
| Number |
Date |
Country |
| 2611668 |
Oct 1976 |
DEX |
| 861880 |
May 1956 |
GBX |
| 1033827 |
Jun 1966 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
94338 |
Sep 1987 |
|
Patent Grant
4977758
