GB2147015A - Electronic actuators for knitting machines - Google Patents

Abstract

An electronic actuator for a knitting machine has electromagnet devices (4) having armatures (6) pivotable at one end and projecting from the devices (4) at the other end, the armatures (6) being movable in evenly spaced planes. The devices (4) operate, upon coil energisation, at least four cranked actuator blades (10) pivotable about a common axis (12) extending transversely to the planes and connected at one end to the armatures (6) and having at the other end cam faces (16) for moving pattern jacks of a knitting machine in the direction of the axis (12). The armatures operate to pivot the actuator blades in the same general plane to move the cam faces (16) to and from a pattern jack engaging position. <IMAGE>

Description

SPECIFICATION Electronic actuators for knitting machines The invention relates to electronic actuators for knitting machines particularly to knitting machines having pattern jacks shifted selectively axially in tricks.

Numerous proposals have been made for electronic actuators which have actuators which are movable electro- magnetically to control needle selection. A wide variety of overall lay-outs have been suggested. Drawbacks have generally emerged on cost and reliability.

The invention has amongst its objects to provide an electronic actuator of improved performance and construction.

No single feature is believed to be responsible for the advantageous features of the invention rather there is a combination of features which function together to provide the improved result.

The invention provides an electronic actuator for a knitting machine including and electronic device having an armature pivotable at one end and projecting from the device at the other end and a cranked actuator blade pivotable about an axis, connected at one end of the armature and having at the other end a cam face for moving pattern jacks of a knitting machine in the direction of the axis, the armature and blade being pivotable about parallel axes in substantially a common place.

Suitably each column includes a plurality of electromagnet devices and blades are provided pivotable respectively in evenly spaced planes and the actuator blade is common to all actuator blades and the electromagnet devices are arranged superimposed in a column which mounts the armatures for pivoting about a substantially common axis.

Preferably then the electromagnet devices are associated with means for adjusting their longitudinal positions in the slideways to thereby adjust the degree of projection of the cam faces.

Conveniently the blades are restrained against axial movement on the common axis by pairs of blades lying against the actuator blades adjacent the axis and the ends of the blades near the cam faces are supported in slots. This gives a light actuator blade movement whilst providing good location.

The actuators can be utilised so that the engagement between the pattern butts of jacks in tricks of the cylinder of the knitting machine does not result in a significant force on the actuator blade tending to move the cam face out of its operative pattern butt engaging position.

Drawings: Figure 1 shows a side view of an electronic actuator according to the invention: Figure 2 shows a front view of the actuator of Figure 1; Figure 3 shows a top view of the actuator of Figure 1; and Figure 4 shows a transverse section through the actuator of Figure 1.

With reference to the Figures, an actuator 2 includes eight electromagnet devices 4 with pivotable armatures 6.

The armatures 6 pivot in parallel spaced planes 8. The armatures 6 operate actuator blades 10 having a pivot axis defined by a shaft 12. The blades 10 are cranked and have a slot 14 at one end for connecting to the armatures 6 and have cam faces 16 at the other end for operating pattern butts travelling in the area around the cylinder 46 indicated at 48 in Figure 4.

The electromagnet devices 4 are arranged in two columns 18 each including a post 20 with slideways 22. Slides 24 mounting the electromagnet devices 4 are provide in the post 20. The slideways accurately locate the devices heightwise. Eccentric screws 27 (Figure 3) can be operated to shift the devices 4 lengthwise in the slideways 22 to adjust the extent of projection of the cam faces 16, permitting them to be aligned in an easy manner without influencing or restricting the stroke. Bolts 29 can be tightened subsequently to secure the devices 4 firmly in the position to which they are adjusted by the screws 27. The electromagnet devices 4 include a mounting 28 supporting a coil 30 on a former 32 between permanent magnets 26.

Pole pieces 31 limit travel of the armatures 6. The free ends of the armatures 6 carry plastic pivots 33.

The actuator blades 10 are located on the shaft 12 by a comb-like arrangement blades 34 having a substantially semi-circular aperture received in a slotted member 36. The blades 34 locate axially the actuator blades 10 on the shaft 12. The end of the blade 10 adjacent the cam faces 16 is located against vertical movement by slots 38 in a slotted member 40. The slotted member 36 and the slotted member 40 are supported between a top plate 42 and a bottom casting 44.

With particular reference to Figure 4, in use the whole assembly is mounted adjacent a cylinder 46 of a sock knitting machine so that the cam faces are capable of engaging the pattern butts 48 on the leading side of the assembly.

In use the permanent magnets 26 hold the actuator blades 10 so that the cams faces 16 are either kept projected into the path of pattern butts (as shown in solid lines in Figure 4) 48 or retracted of the path of the pattern butts 48 (as shown dotted lines in Figures 4). To effect a change the electromagnetic devices are appropriately energized and the actuator blades will then be reset. When the pattern butts first strike a projected cam face 16, the resulting force tends to confirm the position of the actuator blade 10 concerned. The electromagnet device controlling the blade 10 need not resist the force which results on engagement of the pattern butts and the cam face.

The electromagnet devices 4 may be mass produced devices of low cost as produced for example by Harting. By mounting them in the columns 18, they can be easily exchanged and wiring can be conveniently passed from the bottom of the respective columns 18 to the individual devices 4.

The slides 24 are secured by bolts 29 to the post 20 but they have not been shown in all cases for simplicity's sake. Similarly the bolts for securing the post 20 onto the bottom casting 44 have not been shown.

By engaging the plastic pivots 33 in the slots 14 of the blades 10, the armatures 6 are connected to the blades 10 in a way which provides little friction and little play.

The blades 10 themselves can be made very rigid in spite of their length because the blades 10 are flat and the actuating forces are applied in the plane of the blades 10 themselves. The cam faces 16 are supported near their end by the slots 38 in the slotted member 40 so that the reaction forces from engaging the pattern butts 48 transverse to the planes of the blades 10 are not transmitted to the body of the blades 10. The actuator blades 10 are subjected to very little friction by the blades 34 yet are accurately located on the shaft 12 to ensure proper alignment with the plane of operation the armatures 6.

In spite of the large size of the blades 10, they can be operated satisfactorily by the electromagnet devices 4 as the period of time for operating the devices 4 corresponds approximately to the time necessary for eight needle increments to pass to datum position. It is hoped that the new arrangement will permit reliable operation for needle selection on for example double cylinder machines and will reduce to some extent the problems encountered previously with lighter, more compact high speed actuator systems.Whilst the system may appear to be a collocation of known components, the combination of (A) a sloped cam face 16 which tends to lift pattern butts 48 in their tricks (B) with the cranked planar actuator blade pushed by the force of engagement with the butts to confirm the position of the armature 6 and (C) operated by a bi-stable electromagnet device so as to reduce the period of electromagnet energization, provides a highly effective interface between the mechanically operated parts of the knitting machines and the eletromagnet output devices of a microprocessor for controlling the knitting machines.

The arrangement is such that, on coarse gauge knitting machines in which the wide needle spacing gives more time for insertion of the actuator blades, only four actuator blades may be adequate to provide the necessary needle selection, whereas on fine gauge machines two columns are used as described giving eight actuator blades at each ac tuato r.

Claims (10)

1. An electronic actuator for a knitting machine including an electromagnetic device having an armature pivotable at one end and projecting from the device at the other end and a cranked actuator blade pivotable about an axis, connected at one end of the armature and having at the other end a cam face for moving pattern jacks of a knitting machine in the direction of the axis, the armature and blade being pivotable about parallel axes in substantially a common place.

2. An actuator according to claim 1 in which a plurality of electromagnet devices and blades are provided pivotable respectively in evenly spaced planes and the actuator blade axis is common to all actuator blades.

3. An actuator according to claim 2 in which the electromagnet devices are arranged superimposed in a column which mounts the armatures for pivoting about a substantially common axis.

4. An actuator according to claim 3 in which at least four electromagnet devices are arranged in at least two columns with the actuators in each column superimposed, the devices in each column being angularly off-set with respect to the common axis and the blades operable by the devices in the respective columns alternating.

5. An actuator according to either claims 3 or 4 in which the or each column includes a post having slideways into which the electromagnet devices can be secured and in which the devices are bi-stable devices with permanent magnets on each side of coils enveloping the armatures, no retun springs being provided.

6. An actuator according to claim 5 in which the electromagnet devices are associated with means for adjusting their longitudinal positions in the slideways to thereby adjust the degree of projection of the cam faces.

7. An actuator according to any of the preceding claims in which the or each blade is restrained against axial movement on the blade pivot axis by a pair of blades lying against the actuator blade adjacent the axis and the end of the actuator blade near the cam faces is supported in a slot.

8. An electronic actuator substantially as shown and described with reference to the Figures.

9. An electronic actuator for a knitting machine having a plurality of electromagnet actuators in accordance with any preceding claim and having the cam faces of the actuator blades disposed in such a manner that the force of a pattern butt striking the cam face of the blade is resolved by the common axis of the blades.

10. An electronic actuator for a knitting machine according to claim 9, the actuators being shielded by a housing with sidewalls converging towards the cylinder and with the cam faces being on the leading side of the common axis with respect to the direction of rotation of the knitting machine.