GB1571974A - Woodwork moulding machine - Google Patents

Description

(54) WOODWORK MOULDING MACHINE (71) We, WADKIN LIMITED, a British Company, of Green Lane Works, Green Lane Road, Leicester, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to woodwork moulding machines.

The invention is an improvement in or modification of the invention described and claimed in our British Patent No. 1,490,277.

That Patent Specification describes the advantages that may be gained by rotating a 2-bladed moulding cutter block at speeds considerably higher than those obtainable with prior art moulding machines. The maximum speeds at which moulding cutter blocks have previously been run is about 9000 r.p.m., whereas our Patent No.

1,490,277 proposed operating speeds in the order of 18,000 r.p.m. To achieve the necessary stability it was proposed that the rotary cutter should be formed with an integral stub shaft, the rotary cutter and stub shaft being formed from a single piece of metal. In our other Patent Specification no mention was made of whether the cutter blades should be integral parts of the rotary cutter or removable therefrom, but the only embodiments disclosed were of cutters in which the blades and cutter body were integral.

The improvement or modification which is the subject of this Patent Application is the provision of at least one removable pair of cutter blades in the rotary cutter of such a woodwork moulding machine. To retain each cutter blade in the machine against the very considerable centrifugal forces experienced at such high speeds of rotation, each blade is provided with a longitudinally serrated, rear face that cooperates with a complementary serrated face of a groove in the cutter body, and is wedged into firm contact with this complementary face by a wedge member in the groove.

Before using a rotary cutter in a moulding machine according to this invention, the blades are ground to a desired profile while clamped in the cutter body. This is possible using modern grinding techniques, and involves removing the whole of the cutter from the female tapered bore of the moulding machine and mounting the cutter on a moulding grinding machine which permits the grinding of the desired contour on the moulding cutter blades, with each blade being ground to the same contour. The grinding machine uses a template to reproduce the contour accurately. When ground in this way, the cutter blades each have a relief taper over the whole of their width, and can be used without the need for jointing.

Preferably only two cutter blades are provided on the rotary cutter, which is then balanced for high speed operation. The taper mounting of the stub shaft of the cutter into the spindle of the moulding machine provides the precise axial alignment which enables the moulding machines of our Patent No. 1,490,277 to achieve such high speeds in practice.

The invention is illustrated by the accompanying drawings of which: Figure 1 is a side elevation of a rotary cutter of a woodwork moulding machine according to this invention; Figure 2 is a section taken along the line X-X of Figure 1; and Figure 3 is an end elevation of the moulding cutter of Figure 1, viewed from the right as shown.

The rotary cutter illustrated in the drawings is suitable for use in a woodwork moulding machine having a drive spindle as illustrated in Figure 1 of Patent No. 1,490,277. It comprises a cutter body 10 having a male tapered portion 12 into which is tapped a blind bore 14 which is screw-threaded for engagement with the cooperating screw thread 8 of the draw bar 7 of the drive spindle of Figure 1 of Patent No. 1,490,277. The cutter body 10 and male tapered stub shaft 12 are formed integrally from a single piece of metal.

Into the body 10 are milled two longitudinal grooves 16, spaced diametrically one opposite the other. Each groove is for mounting a cutter blade, and has a longitudinally serrated face 18 which in use is the forwardly facing face when considered in the direction of rotation. Into the grooves 16 are placed a pair of cutter blades 20 each of which has a serrated rear face 22 that is of complementary shape to the serrated face 18. The cutter blades 20 are wedged against the faces 18 by means of a pair of wedges 24 which extend longitudinally for the entire width of the cutter body. Each wedge 24 is provided with a concave outer face 26 and wedging faces 28 which are divergent in the direction of the axis of the cutter body.Grub screws 30 are provided within the wedges 24 and in use are screwed downwardly against a radially inner face 32 of each of the grooves 16 to force the wedges radially outwardly so as to effect the necessary wedging action. In use, when the cutter rotates at high speeds the wedging action is increased by a centrifugal force on the wedges 24.

In use, the two cutter blades 20 are firmly wedged into the grooves 16, and then the desired profile is ground onto the blades with the cutter mounted in a grinding machine.

The mounting in the grinding machine is between the tapped bore 14 in the stub shaft 12 and an axial tapped bore 34 at the opposite end of the cutter body. The profile to be ground is dictated by the shape of the woodwork moulding to be produced using the cutter, and the result is a continuous heel 36 across the full width of each blade 20. After grinding, the cutter is rotated at high speeds and balanced by removing small portions of metal from an end face 38, until it becomes stable for use at the 18,000 r.p.m. contemplated. The cutter shown in the drawings can be used even at those high speeds in the production of wood mouldings, as the male taper on the stub shaft 12 holds the cutter in precise axial alignment on the machine spindle. The high speed provides the advantage of surface finish explained in Patent Specification No. 1,490,277.

WHAT WE CLAIM IS: 1. A woodwork moulding machine according to any one of the claims of our Patent No. 1,490,277, wherein the rotary cutter body, which is integral with the stub shaft, has at least one removable pair of blades, and each blade is provided with a longitudinally serrated rear face that cooperates with a complementary serrated face of a groove in the cutter body, and is wedged into firm contact with the complementary face by a wedge member in the groove.

2. A woodwork moulding machine according to claim 1, wherein the cutter comprises a single pair of cutter blades in diametrically opposed grooves in the cutter body.

3. A woodwork moulding machine having a rotary cutter substantially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. thread 8 of the draw bar 7 of the drive spindle of Figure 1 of Patent No. 1,490,277. The cutter body 10 and male tapered stub shaft 12 are formed integrally from a single piece of metal. Into the body 10 are milled two longitudinal grooves 16, spaced diametrically one opposite the other. Each groove is for mounting a cutter blade, and has a longitudinally serrated face 18 which in use is the forwardly facing face when considered in the direction of rotation. Into the grooves 16 are placed a pair of cutter blades 20 each of which has a serrated rear face 22 that is of complementary shape to the serrated face 18. The cutter blades 20 are wedged against the faces 18 by means of a pair of wedges 24 which extend longitudinally for the entire width of the cutter body. Each wedge 24 is provided with a concave outer face 26 and wedging faces 28 which are divergent in the direction of the axis of the cutter body.Grub screws 30 are provided within the wedges 24 and in use are screwed downwardly against a radially inner face 32 of each of the grooves 16 to force the wedges radially outwardly so as to effect the necessary wedging action. In use, when the cutter rotates at high speeds the wedging action is increased by a centrifugal force on the wedges 24. In use, the two cutter blades 20 are firmly wedged into the grooves 16, and then the desired profile is ground onto the blades with the cutter mounted in a grinding machine. The mounting in the grinding machine is between the tapped bore 14 in the stub shaft 12 and an axial tapped bore 34 at the opposite end of the cutter body. The profile to be ground is dictated by the shape of the woodwork moulding to be produced using the cutter, and the result is a continuous heel 36 across the full width of each blade 20. After grinding, the cutter is rotated at high speeds and balanced by removing small portions of metal from an end face 38, until it becomes stable for use at the 18,000 r.p.m. contemplated. The cutter shown in the drawings can be used even at those high speeds in the production of wood mouldings, as the male taper on the stub shaft 12 holds the cutter in precise axial alignment on the machine spindle. The high speed provides the advantage of surface finish explained in Patent Specification No. 1,490,277. WHAT WE CLAIM IS:

1. A woodwork moulding machine according to any one of the claims of our Patent No. 1,490,277, wherein the rotary cutter body, which is integral with the stub shaft, has at least one removable pair of blades, and each blade is provided with a longitudinally serrated rear face that cooperates with a complementary serrated face of a groove in the cutter body, and is wedged into firm contact with the complementary face by a wedge member in the groove.

2. A woodwork moulding machine according to claim 1, wherein the cutter comprises a single pair of cutter blades in diametrically opposed grooves in the cutter body.

3. A woodwork moulding machine having a rotary cutter substantially as described herein with reference to the accompanying drawings.