GB2331726A - Cutting assembly - Google Patents

Abstract

A cutting assembly has cutting tools suitable for removing material from work pieces, for example, the removal of burrs from welded plastics extrusions formed into window frames, wherein the assembly comprises a carrier 50 arranged to move reciprocally in a linear direction and cutting tools 53 and 67, cutting tool 53 being movable in a linear direction Z for operating on a linear surface (12B, Figure 2A) during the cutting operation and cutting tool 67 being movable in a direction for operating on a surface 12A inclined to the linear surface (12B). A support 65 for cutting tool 67 is moveable relative to the carrier 50 to follow the inclined surface and is biassed to urge the cutting tool 67 towards the work piece. The carrier 50 and support 65 are mounted for pivotal movement about the axis of pivot 56. A clamping assembly for clamping the workpiece during the cutting operation is also disclosed (see Figure 1).

Description

2331726 1 CUTTING ASSEMBLY This invention relates to cutting assemblies

and in particular cutting assemblies having cutting tools in the form of knives suitable for removing material from workpieces.

Cutting tools are used to remove material from plastic extrusions at the joints between assembled extrusions and such cutting tools are relatively straightforward when the surface to be cut lies in a single plane. However when there are adjacent surfaces inclined to one another the cutting operation becomes more complex. It is an object of the invention to provide a cutting tool of simple construction which is suitable for this purpose.

According to the invention a cutting assembly comprises a cutting tool, a support for said tool, and a mounting for said support, said mounting being pivotally mounted for pivoting of the mounting and support about the axis of the pivot, the support being movable in its longitudinal direction relative to said mounting and the cutting tool being mounted on said support so that during a cutting operation the mounting moves in a linear direction and the cutting tool moves in a direction inclined to said linear direction, the support in its longitudinal direction being biased to urge the tool towards a workpiece.

Preferably the tool is associated with a tool holder which is movable to a limited extent relative to said support.

The cutting assembly may comprise a further cutting tool, a carrier for said further tool, said mounting being pivotally carried on said carrier for said pivoting action to take place about a pivot at a right angle to the longitudinal movement of said support, and said further cutting tool being movable in said linear direction.

In one arrangement said cutting tools are arranged to successively remove material from two relatively inclined surfaces, each tool operating on one of said surfaces, during said linear movement of the mounting.

2 In another aspect a cutting system for operatmg on a workpiece comprises a carrier arranged to be reciprocally movable in a linear direction, cutting tools for operating on relatively inclined surfaces of the workpiece including a first cutting tool operating on one of said surfaces and a second cutting tool operating on the other of said surfaces, the second tool being movable in said linear direction, and the first tool being movable in a cutting action in a direction inclined to said linear direction, the support for the first cutting tool being movable relative to the carrier whereby to follow said inclined direction.

In one arrangement said support is arranged to be pivotable about an axis at a right angle to said linear direction. In addition the support may be arranged to move in its longitudinal direction which urges the associated tool into engagement with a workpiece. By the combination of said longitudinal and said pivotal movements the first cutting tool is able to effect a cutting operation on a workpiece surface lying at an angle to said linear direction and to disengage the cutting tool from the workpiece upon completion of the cutting action.

Said longitudinal direction of the support extends at an acute angle to the linear direction and the extent of pivoting of the support is limited.

Further features of the invention appear from the following description of an embodiment of the invention given by way of exwnple only and with reference to the drawings, in which:

Fig 1 is a plan view of a clamping assembly in which the cutting assembly of the invention is intended to be used, Figs 2A and 2B are side elevations of a cutting assembly at different stages of a cutting operation, and Fig 3 is a plan view of the cutting assembly of Figs 2A and 2B.

Referring to the drawings and firstly to Fig 1 there is shown a clamping assembly the subject of our prior British patent application 9612949.5 in which the cutting assembly of the present 3 invention is intended to be used.

The clamping assembly shown in Fig 1 is intended for a workpiece W (of which only part is shown) which, in this case, is a window frame formed of plastic extrusions which are assembled together. Thus the frame comprises a transom element 10 and a side frame element 11 which are welded together at 12 and 13 at the junction between the elements 10 and 11. The welds 12 and 13 usually leave portions of plastics material standing proud of the join and the purpose of the assembly is to hold the window frame in position while the join is acted upon to remove excess material, as will be describe& The assembly shown is mounted on a framework having supports (not shown) for the workpiece W and the purpose of the assembly is to locate the workpiece W in the horizontal plane. However the workpiece can be located in any plane inclined to the horizontal or vertically. The frame carries two clamps 14 and 15 aligned with one another and spaced apart along the side of the fl-ame member 11. The clamps 14 and 15 may be fixed or movable and have clamping faces to engage the side of the frame 11.

The clamping assembly includes two sets of linkages 17 and 18 disposed to opposite sides of the transom member 10 and operated by a common drive 19 which may be in the form of a pneumatic or hydraulic cylinder having a piston rod 20 attached to a pin 21 for movement in the direction A.

Each set of linkages 17, 18 comprises similar elements including a crank arm 23 pivotable about a pivot 24 and having a slotted opening 25 engaged by the pin 2 1. At the other end of the crank arm is a pivot pin 26. The pivot pin 26 is arranged for movement along a rectilinear path Y-Y or X-X defined by a slot (not shown).

Pivotally attached to the pins 26 are a pair of links D3, D4 and D I, D2 which are pivotally attached at their opposite ends to pivotal plates E3, E4 and El, E2 respectively. These plates are in turn pivoted about pivots 27, 28 and 29, 30. The plates E3, E4 and E 1, E2 are each of generally triangular configuration and each have pivotally attached thereto at pivots 31, 32 4 and 33,34 clamping members F3, F4 and Fl, F2. It will be seen that the pivots for links D3, D4 and DI, D2 and the pivots 27, 28 and 29, 30 and pivots 31, 32 and 33, 34 are located at the respective comers of the triangular plates.

The clamping members F3, F4 and F 1, F2 each have a clamping surface S arranged to engage surfaces of the workpiece and it would be seen that the clamping members F2 and F3 engage opposite sides of the transom member 10 of the workpiece whereas the clamping members F4 and FI engage aligned sides of the workpiece 11 opposite to the clamping members 14 and 15. Each of die clamping members F3, F4 and FI, F2 are pivotable about their respective pivots.

The drawing shows in chain lines the positions of the clamping members F3, F4 and F I, F2 after the linkages have been moved to a clamping position which, in this case, is the full possible movement when the piston rod 20 is fully extended. This gives a minimum transorn thickness shown, the maximum m thickness being indicated by dimension T. Similarly there is a minimum and maximum thickness of the workpiece element 11 which can be accommodated.

Operation of the clamping assembly is by locating the workpiece W in position on the supports of the frame with the piston rod 20 in its retracted position. The piston rod 20 is then extended until the clamping members Fl-F4 engage the respective surfaces of the workpiece W thereby clamping the workpiece in position. It will be seen that the workpiece is fully clamped with the three illustrated limbs of the workpiece engaged between opposed clamping surfaces. Once fully clamped the workpiece may be acted upon by reciprocal cutting assemblies 40 and 41 movable in the directions Y-Y and X-X respectively aligned with the joins 12 and 13. The assemblies 40 and 41 are driven by suitable drive means in linear direction Z to engage the joins 12 and 13 and remove excess material therefrom to give a satisfactory appearance to the joins.

In the present case the joins or welds 12 and 13 have mutually inclined portions 12A and 1213, the portion 12A being a bevelled portion on the inner edges of the elements 10 and 11.

The weld portion 12B is aligned with the linear direction Z whereas the portion 12A is inclined at an acute angle to direction Z, such angle being different for different frames.

Each cutting assembly 40 and 41 includes a carrier 50 mounted on the end of a piston rod 51 for movement in the direction Z, generally aligned with the weld 12 or 13. The carrier 50 carries, extending downwardly from the carrier, a tool holder 52 at the lower end of which is mounted a cutting tool 53 having a forwardly directed knife-like cutting edge 54 arranged to be of a width suited to the associated weld on surface 12B. In addition the tool 53 and edge 54 are aligned with said surface 12B lying parallel to the direction Z.

Towards the upper end of the carrier 50 is mounted amounting 5 5 through a pivot 5 6 which extends at a right-angle to the direction Z and in a generally horizontal direction.

The carrier 50 also carries an adjustable stop 57 which is arranged to engage the upper surface of the mounting 55 through a vertically adjustable rod 58 thereby limiting the extent of upward movement of the rear and of the mounting 55.

Mounted on the mounting 55 are longitudinal support members 60 comprising cylindrical rods which extend through bores 61 in the mounting 55, there being a space between the outer side of each support member 60 and the associated bore 61 which accommodates a spring 62 arranged to bias the associated support member downwardly in the axial direction of the support member 60. The extent of movement of the support members 60 in said downwards direction is limited by a stop assembly 63 having a longitudinally adjusted stop member 64 arranged to engage the mounting 55 at its lower end.

The support members 60 carry a cutting tool and holder 67 at its lower end through a tool mounting member 65 secured to the support members 60. The tool holder 67 is removably attached to the member 65 for replacement.

The tool holder 67 incorporates a cutting tool having a knife-like cutting point 68 at its forward end and behind the cutting point 68 the cutting tool is formed with a surface 69 lying 6 at a right-angle to the longitudinal axis of the support member 60.

As can be seen in Figs 2A and 2B the support members 60 lie at an acute angle to the vertical, the angle being selected according to the inclination of the surface 12A to the direction Z and the angle of the support members 60 being adjustable according to the movement of the mounting 55 about the pivot 56 and the setting of the stop member 57.

In order to accommodate small inaccuracies of the location of the welds 12 and 13 in relation to the cutting assembly the tool holder 67 is loosely mounted on the tool support 65 so that it may be moved to a limited extent in relation to said tool support to align the cutting tool with the surface 12A. It will be appreciated that such alignment will take place automatically due to the centring effect of the surfaces adjacent the associated weld surface 12A.

In Fig 2B the cutting assembly is shown just prior to a cutting operation of the tool 67 of the surface 12A. As the carrier 50 is moved in the direction Z the cutting tool 67 engages the surface 12A to remove material therefrom. As the carrier 50 progresses in the direction Z the support member 60 is retracted along the bore 61 against the action of the spring 62 whereby the cutting tool moves upwardly along the inclined surface 12A. Once the cutting tool 67 reaches the upper limit of the surface 12A the tool is disengaged from the cutting action and portion 70 of the cutting tool acts as a shoulder to engage with the surface 12B but without a cutting action thereon.

After this stage has been reached continued movement of the carrier 50 in the direction Z brings the cutting tool 53 into position engaging the surface 12B. From this position the cutting tool 53 removes material from the surface 12B by the engagement of the point 54 with the material to be removed.

After completion of a cutting action a reverse movement of the carrier 50 returns the cutting tools to their start position of Fig 2B.

It has been found that the combination of the cutting tools 67 and 53 is able to effect a cutting 7 action on the two inclined surfaces 12A and 12B and it will be appreciated that if only the inclined surface needs to be acted upon the cutting tool 53 can be dispensed with. Similarly when a surface lying parallel to the direction Z is to be acted upon the cutting tool 67 can be omitted.

The cutting tools can take a form suited to the purpose which may be of any convenient kind depending on the material to be removed.

8 CLA1MS 1. A cutting assembly which comprises a cutting tool, a support for said tool, and a mounting for said support, said mounting being pivotally mounted for pivoting of the z mounting and the support about the axis of the pivot, the support being moveable in its longitudinal direction relative through said mounting and the cutting tool being mounted on said support so that during a cutting operation the mounting moves in a linear direction and the cutting tool moves in the direction inclined to said linear direction, the support in its longitudinal direction being biassed to urge the tool towards the work piece.

2. A cutting assembly according to claim 1 wherein the tool is associated with a tool holder which is moveable to a limited extent relative to said support.

3. A cutting assembly according to claim 1 or 2 which comprises a finiher cutting tool, a carrier for said further tool, said mounting being pivotally carded on said carrier for said pivoting action to take place about a pivot at a right angle to the longitudinal movement of said support, and said further cutting tool being moveable in said linear direction.

4. A cutting assembly according to claim 3 wherein said cutting tools are arranged to successively remove material from two relatively inclined surfaces of the work piece, each tool operating on one of said surfaces, during said linear movement of the mounting.

5. A cutting system for operating on a work piece which comprises a carrier arranged to be reciprocally moveable in a linear direction, cutting tools for operating on relatively inclined surfaces of the work piece including a first cutting tool operating on one of said surfaces and a second cutting tool operating on the other of said surfaces, the second tool being moveable in said linear direction, and the first tool being moveable in a cutting action in a direction inclined through said linear 9 direction, the support for the first cutting tool being moveable relative to the carrier whereby to follow said inclined direction.

6. A cutting system according to claim 5 wherein said support is arranged to be pivot able about an axis at a right angle to said linear direction.

7.

A cutting system according to claim 6 wherein the support is arranged to move in its linear direction and urges the associated tool into engagement with the work piece.

8.

A cutting system according to any one of claims 5, 6 & 7 wherein said longitudinal direction of the support is at an acute angle to the linear direction and the extent of pivoting of the support is limited.

9. A cutting assembly substantially as described with reference to the drawings.