A FASTENER

Field of the Invention

The present invention relates to fasteners suitable for use in inhibiting movement between a tool attachment and a tool mounting shaft. A particular application of the invention is in textile plotter cutter machines and although it will be convenient to hereinafter describe the invention with reference to textile cutting machines, it is to be understood that this is not to be taken as a limitation of the scope of the invention.

Background of the Invention

In machinery, tools are required to be exchanged and replaced from time to time in order to carry out different operations on a workpiece or workpieces using the same machine even where there are several tools mounted on a turret head. Often, especially in textile plotter cutter machines, an entire tool head, including motors, controllers, and the associated hardware are all replaced when, the tool is replaced. This leads to additional expense, wasted capital in doubling of machinery and in any event, is a difficult and time- consuming operation.

The ^* present invention seeks to ameliorate one or more of the abovementioned disadvantages.

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Summary of the Invention

According to one aspect of the present invention there is provided a quick release fastener apparatus suitable for inhibiting relative movement between a tool attachment and a tool mounting shaft, .the quick release fastener apparatus including: a fastener body mounted in a fastener aperture for rotational movement between a release position disposed at a first selected angular position and a fastened position disposed at a second angular position, the fastener body further including a cam which includes a first lobe wherein in the fastened position the first lobe extends into a tool connecting aperture for connecting the tool attachment and tool mounting shaft together, the lobe being withdrawn from the connecting aperture when the fastener body is moved to the release position.

Preferably the angular displacement between the release and the fastened position is approximately 180°.

Preferably a recess is disposed in either the tool attachment or tool shaft so that the first lobe may abut the recess when in the fastened position. Preferably the recess has a cross- section corresponding with that of the abutting portion of the lobe.

Preferably a fastener housing is provided in order to house the fastener aperture. Preferably the fastener housing is mounted on the tool attachment. Preferably the cam is integral with the fastener body.

In one arrangement the cam includes a helical engagement wall portion so that when driven, the rotation of the fastener body gradually advances an engagement portion of the helical engagement wall along a fastener body axis into the connecting aperture. Preferably the lobes are disposed within the cross-section of the fastener body.

Preferably the fastener body includes a drive head for engagement with a driving means, and a retention means disposed at an insertion end, the cam being disposed at an

intermediate region. Preferably the drive head is a hexagonal socket head.

Preferably the retention means includes a circlip which mounts in a channel for retention of the fastener body in the fastener aperture. Preferably a detent is provided to retain the fastener body in the release position. Preferably the detent is a biased projection which engages with a land to retard rotation of the fastener body about a fastener body axis when in the open position.

According to another aspect of the present invention there is provided a textile plotter cutter machine which includes a tool attachment and a tool mounting shaft, and ia quick release fastener suitable for inhibiting relative movement between the tool attachment and the tool mounting shaft, the quick release fastener including: a fastener body mounted in a fastener aperture for rotational movement between a release position disposed at a first selected angular position and a fastened position disposed at a second angular position, the fastener body further including a cam which includes a first lobe wherein in the fastened position the first lobe extends into a tool connecting aperture for connecting the tool attachment and tool mounting shaft together, the lobe being withdrawn from the connecting aperture when the fastener body is moved to the release position.

According to still another aspect of the present invention there is provided a plotter cutter machine which includes a quick release fastener to inhibit relative movement between a tool attachment and a tool mounting shaft.

According to a still further aspect of the present invention there is provided a plotter cutter machine tool attachment which includes a quick release fastener for attachment to a tool mounting shaft.

According to yet another aspect of the present invention there is provided a tool control head which is adapted to mount tools directly or indirectly thereupon, the tool control head including a tool shaft which is hollow so that control assemblies may access the tool region for additional control thereof.

Preferably the tool control head is used in textile operations. Preferred features such as reciprocating shafts, ejectors, hydraulic fluid conduits, pneumatic tubes may be fed down the hollow tool shaft in a manner such as above described.

Brief Description of the Drawings

In order to enable a clearer understanding of the invention, drawings illustrating example embodiments are attached, and in those drawings:

Figure 1 shows a number of views of a quick release fastener in accordance with a preferred embodiment of the present invention including: 1. (a) Side elevation 1. (b) Section of a cam portion

1. (c) End elevation from a drive end;

Figure 2 shows a side elevation view of a tool mounting shaft showing a recess at its end for receiving the cam;

Figure 3 shows a number of views of a quick release fastener assembly including:

3. (a) End elevation section showing a detent means;

3. (b) Exploded end elevation view showing the detent means holding the fastener in the release position; 3. (c) plan view of tool mounting head;

3. (d) plan view of fastener housing;

3. (e) end elevation views of fastener housing;

Figure 4 shows a variety of views of a tool control head, including: 4. (a) Front elevation view;

4. (b) plan view

Detailed Description of a Preferred Embodiment

It will be convenient to hereinafter describe various aspects of the preferred embodiments in combination with one another, but this is not to detract from the fact that there are several individual and separate aspects of the present invention.

Referring to the drawings there is shown a tool control head for a textile plotter cutter machine generally indicated at 10 in Figure 4(a), the tool control head 10 including four tool assemblies 8, 9, 12, 13 mounted on respective tool shafts, 14, 16 at respective lower ends 18, 19 thereof.

The tool shafts 14, 16 include access means 20, so that control means (not shown) may access the tool attachments 12, 13. The access means 20 are in the form of through apertures 22 from an upper end 17, 15 to lower ends 18, 19 of the tool shafts 14, 16. The control means (not shown) are in the form of rotating or reciprocating tools shafts, hydraulic pipes, pneumatic tubes, coolant, and the like (not shown).

The tool attachments 12, 13 and tool shafts 14, 16 are fastened together by a fastening apparatus 30, in the form of a quick-release fastener 31. The quick release fastener 31 includes a fastener body 32 which includes a cam 34 which is offset relative to a fastener axis 35. The fastener body 32 is mounted in a fastener aperture 33 which is disposed in a fastener housing 37 associated with the tool attachment 12, 13. A recess 36 is associated with the tool shaft 14, 16, the recess 36 corresponding in section to the section of the cam 34.

The fastener body 32 is a generally elongate shaft 35 which includes an engagement region 38 at an intermediate region 75, the engagement region 38 including the cam 34. The cam 34 may be helical in shape, but in the preferred embodiment shown, the cam 34 includes lobes 41, 51 and 52. The lobe 41 does not extend beyond the outer diameter of the shaft 35. The cam 34 includes a flat 45 so that, in the release position, the lobe 41 may be

disposed wholly withdrawn from, or wholly adjacent the connecting aperture 61 so that the end 18 of the tool shaft 14, may be received in the connecting aperture 61 to mount the tool attachment 12 on the tool shaft end 18.

A detent 50 is provided so as to retain the fastener body 32 in the release position in which the cam 34 is not in the connecting aperture 61. The detent 50 is in the form of a ball 51 biased towards the fastener body 32 by a biasing means in the form of a spring 53, The ball 51 retards the rotation of the fastener body 32 when it abuts a flat 57.

The recess 36 is in the form of a notch 37 in tool shaft 14, 16. The notch 37 is an arcuate bight 55, of a similar radius to the lobe 41, to facilitate a snug fit and maximum frictional force when engaged with the internal periphery of the bight 55.

In operation the tool attachment 12 is presented to the lower end 18 of the tool shaft 14 by rotating the fastener body 32 to the release position, the fastener body 32 being held in that position by the detent 50. The end 18 of the tool shaft 14 passes through the connecting aperture 61 in the tool attachment 12 and the notch 37 is disposed adjacent the flat 45. The fastener body 32 is then driven or rotated by a socket or wrench through an angular movement slightly less than approximately 180° until the lobe 41 gradually advances into the notch 37 and abuts the interior periphery of the notch 37. Friction holds the lobe 41 in the notch 37 and the tool 60 is held firmly and is inhibited from rotating if the shaft 14 does not rotate. Angular and axial backlash is minimised because the lobe 41 has a semicircular profile which corresponds to the profile of the notch, which makes for a snug fit. A high degree of accuracy with regard to the holding angle and a high holding strength is achieved. The shaft 18 can exert a high degree of control over the tool 60, and the tool 60 is less prone to self-steering because of the strong frictional hold (a snug fit over a large surface area). The gradually increasing radiused contour of the lobes 51 and 52 facilitate release into the release position.

The tool shaft 18 includes splines extending along the outer walls so that recirculating ball bearings may be used to engage with the spline to steer the tool 60 by (controlling the

rotation of the shaft 14). The steering achieved by sprockets 75 and the down force applied by cylinders 70 are thereby separated.

To release the tool attachment 12, the head of the fastener body 32 is turned approximately 180° back until the flat 45 is in the release position and then the tool attachment 12 drops out of the connecting aperture 61. The notch 37 is disposed in the end region 18 of the tool shaft 14 and therefore the tool attachment 12 only needs to drop a few millimetres before it may be removed entirely and renovated or replaced. This enables the .tools to be mounted only a few millimetres above a cutting table.

Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention.