GB2188336A - Circular knitting machines - Google Patents

Abstract

A circular knitting machine is provided with a desired number of striper boxes (2) each containing, in the example given, four striper fingers (6). Selector means (42) rotatable with the cylinder are provided to select one or more of the fingers from one or each box. The selector means comprise a plurality of cam-bearing members (48) which are arranged selectively to pivot under the initiating action of solenoids (46) to an active position in which they are held mechanically and in which a cam face (50) of the appropriate member is caused to project so that it strikes an operating member (12) associated with a striper finger. The member (12) is linked to the finger (6) e.g. by a rack and-pinion arrangement (28, 30, 32, 34). The contact between each of the cam faces (50) with the end portions of the corresponding member (12) takes place in a plane of contact separated from the plane of contact between neighbouring members (12) by an axial and/or radial distance with respect to the machine axis. <IMAGE>

Description

SPECIFICATION Circular knitting machines The invention is concerned with improvements in or relating to circular knitting machines, particularly machines provided with a striping facility.

Circular knitting machines provided with striping mechanisms are capable of producing horizontal (coursewise) bands of knitted yarn in the knitted fabric, said yarn having characteristics, such as of colour, differing from that of the yarn of the basic or ground fabric. Such mechanisms may be arranged to a plurality of stationary locations around the needle cylinder of the machine and conventionally introduce a yarn or yarns to the needles as the cylinder rotates, being provided with means to cut, trap and place the striping yarn as required. The number and arrangements of stripes produced may be varied by selection from the number of striping mechanisms, hereinafter referred to as fingers, within each "striper box", and the number of boxes arranged around the machine.

The object of the present invention is to provide improved facility for selecting desired striper fingers within the striper box, increasing the speed of selection and therefore the versatility ofthe knitting machine.

The present invention provides a circular knitting machine having a group of striper fingers at at least one location adjacent the path of rotation of a needle cylinder ofthe machine, selector means being provided for selection of one or more of said fingers, said selector means being arranged for relative movement with respect to each group of striper fingers and comprising a plurality of movable cam-bearing members each selectively projectible so as to contact an operating member associated with one of the striper fingers during said relative movement, wherein the operation ofthe cam-bearing members is controlled by electromagnetic means, the construction and arrangement being such that operation ofthe electromagnetic means initiates movement of a cam bearing member into a mechanically-held position in which the cam-bearing member contacts said operating member of the selected striperfingers.

Conveniently each group comprises four striper fingers, each associated by mechanical linkage with its operating member. Preferably, the mechanical linkage may incorporate a rack and pinion device.

Contact between each operating member and its corresponding cam-bearing member may advantageously be arranged to take place in a plane of contact separated frorn the plane of contact between neighbouring members by an axial and/or a radial distance with respect to the machine axis.

Advantageously, the operation of each cam-bearing member is controlled by a latching solenoid.

Cancellation of the operation, that is, the return of the operating members of each of the striper fingers to an inoperative condition is preferably by mechanical means, conveniently a cancelling cam member.

In machines arranged to operate according to the invention, there may be provided any selected number of striperfinger groups or boxes, for example from one to forty eight, each box containing fourstriperfingers. Intheexampleofa machine to be described below there are forty eight striper boxes, one set of selector means comprising four cam members and one cancelling cam member. It will be appreciated that the selection offinger(s) from each box may be changed during operation of the machine, the selector means being changed during the travel between adjacent striper boxes to selectorde-selectas required.

There will now be described an example of a machine according to the invention. It will be understood that the description, which is to be read with reference to the drawings, is given by way of exampleonlyand notbywayoflimitation.

In the drawings: Figure 1 is a side view, with parts omitted or broken away for the sake of clarity, of a striper box and a selector means of the machine; Figure2 is a side view of a portion of the selector means of Figure 1; Figure 3 is a plan view of said selector means; Figure 4 is a view of the cam bearing members of the selector means taken in the direction of arrowA of Figure 3; Figure 5is a view of the operating members of the striper box taken in the direction opposite to that of the arrowA of Figure 3; Figure 6shows the pattern of contact of the cam bearing means and the operating members; and Figure 7 is a fragmentary plan view of a rotating frame ofthe machine showing the selector means and a cancelling cam member.

Figure 1 illustrates a group 2 of striperfingers 6 within a striper box 4. There arefourfingers 6 which are positioned side by side (only one is shown) in an inoperative position as shown in the Figure. When it is required to bring a selected one of the fingers into an operating mode,thatfinger6 must be allowed two rise underthe infiuence of a spring 8 so that the finger can perform a conventional operation to provide a yarn to needles of the machine. Sincethis operation is conventional and forms no part of the present invention, no further description thereof is given.

Each finger 6 is retained in its inoperative position by means of a rod 12, one end 14 of which engages a shoulder 16 on the finger 6. The rods, only one of which is shown in Figure 1, lie side by side in a horizontal plane and are arranged for a lengthwise movement with respect to a housing 18securedto the striper box 4. Opposite ends 20 ofthe rods protrude from an operating face ofthe housing 18, as may also be seen in Figure 5.

Lengthwise movement of the rods is controlled by the provision of two location grooves 22, 24 on each rod 12, into which are received spring-loaded ball cathes 26. The rod 12 visible in Figure 1 is depicted in its restraining condition in dotted line, in which its associated striper fingerS is not free to operate and the ball catch 26 contacts with the inner groove 22.

Lengthwise movement of the rod 12 into its release condition (full lines) in which thefinger6 is no longer prevented from operating causes the ball catch 26to engage the outer groove 24 as shown in the Figure.

Movement of each ofthe rods 12 between its restraining and release positions is brought about by a rack-and-pinion arrangement provided for each rod, in which a toothed portion 28 ofthe rod 12 engages with one offour pinions 30,32. The pinions are each driven by engagement by toothed portions of separate pins 34,36,38,40, also arranged for sliding movement in the housing. As will be appreciated from Figure 5, the arrangement of the pins 34,36,38,40 is such that the distance between pins 34 and 36 from their respective rod ends 20 requires the use of larger diameter pinions 30 than the smaller diameter pinions 32 needed to drive the rods associated with pins 38 and 40. Pins 34,36,38 and 40 thus projectfromthe operative face ofthe housing 18 which is stepped to position the pins into separate planes both vertically and horizontally.

It is the selection of one rod from the four rods 12 forthe release of the selected striperfinger 6from the box 4, by means of one appropriate pin from the pins 34,36,38 that will now be described.

Whereas the striper boxes are arranged at selected locations on stationary machine frame parts, the selector means is mounted upon a rotaryframe portion passing each striper box once in each revolution ofthe knitting machine.

In Figure 1,the selector means indicated at 42, is required to depress the selected pin or pins 34,36,38 or40 as it passes the box. If no striperfinger is required to be brought into operation on that revolution, the selector means 42 must keep clear of the pins. In the present example, while there are a plurality of striper boxes on the machine, only one selector means is provided.

The selector means 42 comprising a mounting plate 44supporting fourso-called latching solenoids 46. Each solenoid 46 controls the action of one of fourtwo-armed levers 48. A cam face 50 (Figure 2) is provided on the free end of an outer one ofthe arms of each lever. The construction of one solenoid 46 and its operation on one lever 48 will now be described.

The solenoid 46 comprises a centrally disposed plunger member 52, an outer, bifurcated, end of which projects from the solenoid housing 54. The member 52 is partially received in a centre passage of a permanent magnet 56 within the housing 54. The remainder ofthe member 52 within the housing is surrounded by the windings of an electromagnet 58.

Mounted for limited pivotal movement about a shaft 60 isthe two-armed lever48, an inner arm 62 of which is attached by means of a spring 64to a reaction point 66. The outer arm 68 carries the cam surface 50. A lug 70 depending from the lever 48 pivotally mounts one end of a link 72, the other end being pivotally connected to the lower end of a link 74. The upper end of the link 74is mounted upon a shaft 76 secured in the plate 44. At a mid-point thereof, the link is pivotally pinned at 78 in the fork ofthe bifurcated end oftheplungermembers2.

When the device is at rest the permanent magnet operates to hold the plunger 52 firmly in position, but when a pulse of a first polarity is sent to the windings oftheelectromagnet58,theholding effectofthe permanent magnet 56 is "neutralised" and the plunger 52 is permitted to slide in the housing 54.

The strength of spring 64 is sufficientto pivotthe lever48from its inoperative full line position against a stop bar 80 as shown in Figure 2 into an operative position (in dotted line) and in so dqing causes the link72 to move to the right as viewed in that Figure and the link 74to pivot (to the right) about the shaft 76. This has the effectofwithdrawing the plunger52 from the housing 54.

When it is desired to move the lever 48 backto its inoperative position (de-select), the electromagnet is given a pulse of the opposite polarity which this time augments the influence of the permanent magnet and causes the plunger to be retracted into the housing against the influence of the spring 64. Thus the link74 pivots backto its original position, pulling with it the link 72 which through the lug 70 causes the lever48to return to its full-line position.

Therefore when it is desired to select one striper finger 6 to operate from the fourfingers in anyone striper box 4, the cam surface 50 of the appropriate lever 48is positioned to contact the associated pin 34 or 36, or 38, or40 as it passes the box 4. It will be observed that when the cam surfaces 50 contact the pins, the mechanical stress of impact force is transferred to the shaft 60 and the bar 80, and no strain is imparted to the solenoid itself.Moreover it should be noted that the solenoid operation is not required to control the accurate positioning ofthe operating links and levers. It will also be appreciated that since a single pulse of electrical power is all that is required to select or deselectthe cam surface, the changes of selection and therefore of patterning are very rapid. Thus it is possible to change the selection pattern, if desired, of each of the forty eight boxes so that each operates differently from its neighbours i.e.

a different arrangement of fingers is selected.

However, despite this speed of operation,the solenoids, because they receive pulses ratherthan constant electrical power do not produce sufficient heat to affect the cool running of their operation.

The present example illustrates a single-acting latching solenoid. It will be appreciated that an alternative arrangement may be utilised in which a double-acting latching solenoid is caused to operate the lever 48. In such a case, the movementofthe lever between its two illustrated positions is under solenoid control in both directions and the spring 64 may be dispensed with.

Figure 4 shows the appearance of the selector means of the present example when all four levers 48 are in the non-selecting inoperative condition. The pattern of the cam surfaces 50 is reproduced (in mirror image for reasons that will become clear) in Figure 6 aswhite rectangles. Immediately adjacent each white rectangle is a black rectangle representing the operative position. Figure 6 also shows the pattern of pins 34,36,38 and 40 of Figure 5, and, bearing in mind that pins 38 and 40 are in a different vertical plane to that of pips 34 and 36 (see Figures 1 or3), it will be apparent that each pin is operated by one cam surface 50 only, when that surface is in the "black" position and is superimposed upon the circular pins as it would momentarily appear as the selector means passes the striper box.

Because of the action of the spring 8 (Figure 1)the striper mechanism selected will remain operative in the selected colouryarn until the next selection is made even though in the present example the cam surface is restored to its inoperative position by a cancelling cam 82 provided "upstream" of the selector means. This cam operates by contacting in turn all four rod ends 20, causing them to retract, pivot the pinions 30,32, and thus extend the rods 14 so that they are able to re-engage the shoulders 16 if the next pattern selection does not require that particularstriperfingerto operate.

Various modifications may be made within the scope of the invention as defined in the following

Claims (9)

claims. CLAIMS

1. Acircular knitting machine having a group of striper fingers atat least one location adjacent the path of rotation of a needle cylinder of the machine, selector means being provided for selection of one or more of said fingers, said selector means being arranged for relative movement with respect to each group of striperfingers and comprising a plurality of movable cam-bearing members each selectively projectible so as to contact an operating member associated with one of the striper fingers during said relative movement, wherein the operation ofthe cam-bearing members is controlled by electromagnetic means, the construction and arrangement being such that operation ofthe electromagnetic means initiates movement of a cam bearing member into a mechanically-held position in which the cam-bearing member contacts said operating member of the selected striperfingers.

2. Amachine as claimed in claim 1,wherein contact between each operating member and its corresponding cam-bearing membertakes place in a plane of contact separated from the plane of contact between neighbouring members by an axial and/ora radial distance with respect to the machine axis.

3. A machine as claimed in claim 1, wherein each striper finger is provided with an associated operating member and linked therewith by a mechanical linkage.

4. A machine a claimed in claim 3, wherein the mechanical linkage incorporates a rack and pinion device.

5. A machine as claimed in claim 4, wherein the rack and pinion device ofthe mechanical linkage includes a rod member adapted to contact a body portion of the striper finger and a toothed portion of the operating membercontactable by the appropriate cam-bearing member.

6. A machine as claimed in anyone ofthe preceding claims, wherein the movement of each cam-bearing member into a position in which it iies in the path of an operating member of one of the striper fingers is controlled bya latching solenoid.

7. A machine as claimed in any one of the preceding claims, wherein the operating member of each ofthe striper fingers are returned to an inoperative condition by a cancelling cam.

8. Amachineasclaimed inclaim G,whereinthe cam-bearing member is a two-armed lever, one arm ofwhich is adapted to be contacted by a plungerof the solenoid and the other arm of which is provided with a cam surface adapted to be selectively in contact with said operating membe

9. Acircularknitting machine having a groupof striperfingers at at least one location adjacentthe path of rotation of a needle cylinder of the machine and selector means for selection of one or more of said fingers, constructed and arranged as hereinbefore described with reference to and as shown in the drawings.