GB2225281A - Device for turning wooden objects - Google Patents

Description

2r, z_25281 1 DEVICE FOR TURNING WOODEN OBJECTS The present invention

concerns a device for turning wooden objects, especially logs, said device being 5 defined below in the introductory part of claim 1.

Previously known log debarking machines include those proposed in patent publication 91,571 and the publication of patent application DE 2,345,267. The debarking machine proposed in the former publication comprises two rings connected to each other: a fixed ring and a rotary ring, the log being fed axially through the machine via the centre of the rings. Mounted on the rotary ring are swinging arms,. each with a debarking cutter at the free end. The swinging a2:ns are pressed against the surface of the log, which moves axially through the machine. When the rotary ring is rotated, the swinging arms also revolve about the log. The inner surface of the fixed ring is provided with a toothed rim. This toothing engages tooth wheels arranged in conjunction with the swinging arms to transmit the rotary notion to the debarking cutters. In this way, energy is transmitted fron the rotary ring over the tooth rim and tooth wheels to the debarking cutters. Such a power transmission systen, in which energy is transmitted by means of a tooth rim and tooth wheels, is complex and, in its operating environment, subject to wear and disturbances. Furthermore, producing the toothing for this purpose is expensive as compared to the total manufacturing costs for the whole debarking machine.

The other one of the above-mentioned publications proposes a debarking machine which also comprises a rotary ring supported by bearings on the body of the machine. In this case, too, the log is fed into the machine along the central axis of the ring. Mounted on the rotary ring are swinging arms, and the ends of these are provided with debarking tools. The arms are so 1 2 arranged that they can be turned from th e ring towards the central axis by means of hydraulic cylinders operated by a hydraulic pump, which in turn is driven by an electric motor. Such a debarker construction is complex and subject to disturbances. Therefore, the machine may require a lot of maintenance. Further problems may be encountered in the balancing of the rotary ring.

A drawback common to both of the debarkers described above is that the swinging arms and debarking cutters cannot be turned down from the ring towards the central axis until the log has been fed into the machine. Such an arrangement retards the debarking process. it requires the employment of an operator to take care of turning the swinging arms down against the log after it has been inserted. An alternative solution is to use a specific automatic system for detecting the presence of a log.

The object of the present invention is to achieve an improved device for turning wooden objects, especial- ly logs. To implement this, the device of the invention is characterized by what is presented in the characteristic features part of claim 1.

one of the advantages provided by the device of the invention is that the log fed into the machine need not be rotated but only has to be moved axially forwards, while cutters mounted at the ends of swinging arms pivoted on the rotary ring of the device efficently chip the log surface without the operation of the device being adversely affected by possible curvature or out-of-round shape of the log. The swinging arms of the device of the invention are so implemented that, when a log is being moved axially into the machine, they are automatically swung aside by the log end so that the cutters will move into the operating position and start working the log surface. Moreover, the energy required for rotating the cutters is derived from the kinetic energy of the rotary ring by means of simple and easily 3 replaceable power transmission elements, i.e. belts and pulleys. Thus, no separate energy source is required for the cutters. Each swinging arm of the device is preferably provided with a counterweight and a spring acting in relation to the boss of the arm, so that the arms will move in a controlled fashion e.g. when the end of a log is pushing then aside from the path of the log. In addition, the spring or equivalent allows effective variation of the cutter pressure against the sur- face of the wooden object to be worked.

In the following, the invention is described in detail with reference to the drawings attached, wherein Fig. 1 presents the device of the invention in sectional side view; Fig. 2 presents the device in Fig. 1 in front view; Fig. 3a presents a swinging arm of the device as seen from one side; and Fig. 3b presents the arm in Fig. 3a as seen from the direction of entry of the wooden object.

The device of the invention comprises a body 1, which is mounted on a suitable fixed bed, and a ring 2 supported by bearings on the body 1 and rotated by a power unit, e.g. an electric motor 3, using a suitable power transmission means 4. Pivoted on the ring 2 of the device is at least one arm 5, and this arm is provided with a rotatable cutter 6. The wooden object T to be worked is fed into the device in the direction of the axis A-A of the ring 2, and the turning of the object is effected by means of the rotary ring 2 and the rotatable cutters 6 linked to it by the arms 5.

In the embodiment illustrated by Figs. 1 and 2, the arms 5 are arranged symmetrically relative to the central axis A-A of the ring 2, on different sides of it. Each arm 5 is attached at its boss 8 to the rotary ring 2 by means of a sleeve 9 or a similar holding element. The arm 5 is thus allowed to turn freely about its boss 8.

4 The arm 5 is a longish part having a curvature from the boss 8 to the free end such that, relative to the vertical plane B-B perpendicular to the axis A-A, the arm is curved in the direction away from the rotary 5 ring 2.. i.e. in the log feed direction C.

The arm 5 is also preferably arched between the boss 8 and the free end in such manner that, relative to the straight line D-D (Fig. 1) between the boss 8 and the central axis A-A of the ring 2, the arm turns 10 concavely to one side of this line.

Figs. 3a and 3b visualize the arm 5, detached from the machine and without a cutter 6. The gudgeon 6a which accommodates the cutter 6 and the pulley 14 and constitutes the axis of rotation of the cutter is shown in Fig. 3a.

The curved shape of the arm 5 serves to ensure that, when a log T is being fed into the machine, the obtuse front end T1 of the log will push the arms 5 aside from its path. In this way, the arms 5 automati- cally make way for the log T, so that the ends of the arms 5 together with the rotatable cutters 6 will move into position to follow the log surface. The cutters 6 will start working the log as soon as the arms 5 start following the log surface.

The inner edge 5a of the arm 5 is preferably provided with a protrusion 10 running longitudinally along the arm. When a log T is fed into the machine, this protrusion 10 will meet the log first, effectively turning the arm 5 about its boss 8 to make way for the log. The inner edge 5a can also be somewhat rounded on the log entry side to help the arm swing aside from the way of the log.

The arm 5 is preferably provided with a counterweight 17 and a spring 18 or equivalent, which, relative to the boss the arm 5, are piaced at the end opposite to the rotary cutter 6. The spring 18 presses the rotary cutter 6 towards the central axis (A-A) of the ring 2 and therefore against the surface of the wooden object fed into the machine.

The device of the invention also comprises a fixed ring 7, which is connected to the body 1. The fixed ring 7 is preferably separated by a distance s from the rotary ring 2 in the direction of the axis A-A. Each sleeve 9, attached to the boss 8 of the arm 5, accom- ' modates a rotatable shaft 11. The ends of the shaft 11 are on oppos ite sides of the rotary ring 2, with a pulley 12,13 fitted at each end. Another pulley 14 is fitted on the axle of the rotatable cutter 6. Around the fixed ring 7 is a V-belt acting as a power transmission means 4 and running over each of the pulleys 12. The pulleys 13 at the opposite ends of the shafts 11 are connected by V-belts 16 to the pulleys 14 of the rotatable cutters 6. Instead of V-belts, it is possible to use e.g. cogged belts, chains etc. and corresponding wheels.

When the ring 2 is rotated, the shafts 11 and pulleys 12 attached to it revolve with the ring. The V-belt 4 engaging pulleys 12 remains stationary, but the motion of the ring 2 causes the pulleys 12 to rotate, and these transmit the rotational motion to the shafts 11 and pulleys 13, which, over V-belts 16 and pulleys 14, transmit the motion to the cutters 6.

The invention has been described above mainly with reference to one of its preferred embodiments, but it is obvious that the invention can be implemented in various ways within the scope of the following claims.

6

Claims (6)

1. Device for turning wooden objects, especially logs, said device comprising a body (1), a ring (2) supported by bearings on the body (1) and rotated by a power unit, e.g. an electric motor (3), using a suitable power transmission means (4), said ring (2) being pro- vided with at least one arm (5) which is turnably mounted and provided with a rotatable cutter (6), the-wooden object to be worked being fed into the device in the direction of the axis (A-A) of the ring (2) and turned by means of the rotatable cutter (6), c h a r a ct e r i z e d in that the arm (5) is a longish part having a curvature from the boss (8) toward the free end such that the arm is curved in the log feed direction (C) away from the rotary ring (2).

2. Device according to claim 1, c h a r a ct e r i z e d in that the arm (5) is arched between the boss (8) and the free end in such manner that, relative to the straigh.L'-- line (D-D) between the boss (8) and the central axis of (A-A) the ring (2), the arm turns concavely to one side of this line.

3. Device according to claim 1 or 2, c h a r a c t e r i z e d in that the inner edge (5a) of the arm (5) is provided with a protrusion (10) running longitudinally along the arm.

4. Device according to claim 1, c h a r a ct e r i z e d in that the arm (5) is provided with a counterweight (17) and a spring (18) or equivalent, which, relative to the boss (8) of the arm, are placed at the end opposite to the rotary cutter (6), said spring or equivalent (18) pressing the rotary cutter (6) towards the central axis (A-A) of the ring (2).

5. Device according to any one of the preceding claims, c h a r a c t e r i z e d in that the device comprises a fixed ring (7) and, for each arm (5), a shaft (11) passing through the boss of the arm (5) and 1 1 ( 7 accommodating two belt pulleys (12, 13)/ th at the axle of the rotary cutter is also provided with a belt pulley (14), said fixed ring (7) and the pulleys (12) being connected by a V-belt (4) or equivalent while the pulley (13) at the other end of the shaft (11) and the pulley of the rotary cutter (6) are connected by another V-belt (16), said cutters (6) being rotated by the kinetic ' energy obtained from the notion of the rotary ring (2) and transmitted by the belt (4) around the fixed ring 10 (7).

6. Device for turning wooden objects, substantially as hereinbefore described with reference to the accompanying drawings.

Published 1990&tThe Patent Office. State House, 66'71 High Holborn. London WClR4TP_ Further copies mkvl>e obtained from The Patent Office Sales Branch, St Mary Cray. Orpington, Kent BRS 3RD Printed by Multiplex techniques ltd. St Mary Cray, Kent. Con. 1187