Log cutting machine

Abstract

 The invention relates to log cutting apparatus, particularly mobile log cutting apparatus. A framework (2) mounted on a trailer (1) has a pair of roller tracks (32) for supporting a log thereon located by a stop (26) and clamp (25). A chain saw mechanism (7) mounted on a carriage (4) is movable along the framework on rollers (6) and tracks (3) by a drive (18).

Description

[0001] This invention has reference to log cutting means and has particular reference to mobile log cutting means, that is to say, log cutting means which are capable of being moved, preferably towed, to a position adjacent the position where a tree has been felled so that it may be sawn into strips or planks.

[0002] It is an object of the present invention to provide an improved log cutting means.

[0003] It is a further object of the present invention to provide an improved mobile log cutting means of simple construction.

[0004] According to the present invention a log cutting means comprises a supporting framework, means for locating a log on the framework the framework including a pair of roller tracks, means for moving a log on the roller tracks against the means for locating the log on the framework and a chain saw mechanism mounted on a carriage on the framework and capable of longitudinal movement along the framework to cut the log into strips or planks.

[0005] Log cutting means in accordance with the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Fig. 1 is a plan view (partly cut away) of the log cutting means

Fig. 2 is a side view (also partly cut away) and

Fig. 3 is a sectional view taken on the line

[0006] Referring to the drawings, the log cutting means is in the form of a trailer 1 capable of being towed behind a drive vehicle and which comprises a framework 2 extending at each side of the trailer from the front to the back of the trailer and has an upper outwardly projecting substantially horizontal flange which constitutes a track 3 for a carriage 4. The carriage 4 has a gantry framework 5 and at each lower side of the gantry framework 5 there is provided a twin pair of double rollers 6 (Fig. 2) which engage the upper and lower sides of the track 3 respectively. These twin pairs of rollers roll on the track and are mounted on the gantry framework and arranged so that the carriage 4 is capable of moving lengthwise of the trailer from the back to the front thereof or vice versa.

[0007] The carriage 4 carries an endless chain saw cutting mechanism 7 which passes round a drive mechanism conveniently hydraulic drive mechanisms 8. Conveniently one drive mechanism is movably mounted on one upright member of the carriage 4 and another drive mechanism is movably mounted on the other upright member. The hydraulic drive mechanisms 8 are each mounted on a back plate 9 with four apertured brackets 10 (Fig 2) with a pair of locating posts 11 being part of the gantry framework 5 passing through two apertures arranged one above the other. An internally threaded member 12 is also secured on the back plate and a screw threaded bar 13 is screwed into this internally threaded member so that on rotation of the screw threaded bar 13 in one direction the bracketed hydraulic drive mechanism is raised whereas movement in the reverse direction causes the hydraulic drive mechanism 8 to be lowered. The respective screw threaded bars 13 on opposite sides of the gantry framework have corresponding crown gear wheels 14 at their upper ends which engage with complementary crown gear wheels 15 on a cross shaft 16 which is rotated by a manually operated drive wheel or power drive. It will be apparent that such rotation either raises or lowers the hydraulic drive mechanisms 8 on the opposite sides of the carrier with these drive mechanisms moving in synchronism. A graduation means (not shown) may be provided to enable the operator to be aware of the amount of movement of the hydraulic drive mechanism.

[0008] The carriage 4 is moved on the track 3 by a carriage drive mechanism 18 which drives a winch mechanism 19 (to be hereinafter described) as well as the carriage drive. The drive mechanism 18 is connected through respective clutch mechanisms 20 to the winch mechanism 19 and to a pulley 21 mounted on a cross shaft on which a pair of sprockets 22 are also mounted, one on each side of the trailer, which sprockets have a respective drive chain 23 passing around them. Each drive chain also passes around an idler chain sprocket 24 at the other end of the trailer and the ends of the drive chain 23 are connected to the carriage 4.

[0009] Thus on operation of the drive mechanism 18 the sprockets 22 are rotated to move the chain 23 to pull the carriage 4 on the trailer either in forwards or backwards direction with the pairs of double rollers 6 riding on the track 3. The drive is connected to opposite sides of the carriage and serves to pull the carriage lengthwise of the trailer.

[0010] The winch 1 is driven by the drive mechanism 18. A rope is wound on this winch so that a part of a tree (or log) can be pulled towards the trailer. For example, it can be pulled from a position in which it has been felled towards the trailer. The trailer has four adjustable legs 24 (two of which are shown in Fig. 2) one adjacent each corner of the trailer and these legs are each operable manually or by hydraulic power to raise the front end of the trailer into the position of the trailer illustrated in chain dotted lines in Fig. 2 to retain the trailer in position when it is disconnected from the drive vehicle. It is preferred that when the four legs are lowered into operational position the trailer is inclined downwardly as shown in chain dotted lines in Fig. 2 at an angle of about 10 .

[0011] The log is pulled on the trailer by the winch mechanism 19 and is located in its required cutting position by an adjustable clamp 25 operable by manual or hydraulic means to move the log (as shown in Fig. 2 against a backstop 26 (Fig. 2). To enable the log to be moved easily on the trailer a pair of roller tracks 32 are provided. Each track 32 comprises a series of rollers with their axes arranged parallel to one another and each roller being mounted in a framework so arranged that the individual rollers are inclined transversely of the tracks at an angle of about 30 ⁰ from the horizontal to retain the log between the roller tracks.

[0012] The trailer has a cross shaft 27 clamped to the framework 2 and to the ends of which wheels 28 are secured.

[0013] A pack system 30 is carried on the trailer to supply power for the hydraulic mechanisms.

[0014] The motor of this system is transversely mounted through a worm and wheel drive. The power pack may be in the form of an on board diesel/hydraulic power pack giving independance, or a power pack take off unit which will require drive from the towing vehicle; or an electric motor which will need a mains supply.

[0015] An auxiliary drive motor 31 may also be supplied and fitted to the cross shaft 16 which is used for raising and lowering the drive mechanisms rather than moving them manually.

[0016] When a log is to be cut into strips or planks the log is pulled by the winch mechanism 19 onto the roller tracks 32 and then driven by the drive mechanism 18 and is clamped securely in position between the clamp 25 (Fig.l) and the backstop 26 (Fig.2). The carriage 4 is moved behind the log and the height of the chain saw cutting mechanism is selected to cut the first strip or plank of wood from the log.

[0017] The chain saw mechanism is moved by the drive mechanism 8 with the chain saw out of contact with the log until the carriage is moved forward under the action of the carriage drive mechanism 18 which slowly moves the carriage (and hence the chain saw mechanism) forward - (that is from the right to the left as shown in Fig. 2) until one strip or plank is cut from the log. The carriage is then returned to the starting position, the chain saw mechanism is lowered by an amount corresponding to the desired thickness of the strip or plank and the operation is repeated. This operation is repeated until the log is cut into strips or planks as desired when the trailer with the cut log carried thereon is towed away.

Claims

1. Log cutting means comprising a supporting framework (2), means (25,26) for locating a log on the framework, the framework including a pair of roller tracks (32), means (19) for moving a log on the roller tracks against the means (26) for locating the log on the framework and a chain saw mechanism (7) mounted on a carriage (4) on the framework and capable of longitudinal movement along the framework to cut the log into strips or planks.

2. Log cutting means according to claim 1, characterised in that the roller tracks (32) are each inclined transversely of the tracks to retain the log between the tracks.

3. Log cutting means according to claim 1 or claim 2, characterised in that the carriage (4) has a gantry (5) with a drive mechanism (8) mounted on at least one of the upright members of the gantry and connected to the chain saw cutting mechanism (7).

4. Log cutting mechanism according to claim 3, characterised in that the gantry framework (5) has a pair of supporting rollers (6) on each of the upright members of the gantry which roll on a track (3) on the framework (2) so that the gantry is capable of moving lengthwise of the framework.

5. Log cutting mechanism according to claim 1, characterised in that the means for locating the log on the framework includes an adjustable clamp (25) and a backstop (26), the clamp (25) being arranged to urge the log against the backstop.

6. Log cutting mechanism according to any one of the preceding claims characterised in that the framework (2) is mounted on a trailer (1).

7. Log cutting mechanism according to any one of the preceding claims having wheels (28) to support the mechanism to be towed by a drive vehicle and adjustable legs (24) to position the mechanism when the trailer.(1) is disconnected from the drive vehicle.

8. Log cutting mechanism according to any preceding claim characterised in that the framework (2) is adapted to be supported and the mechanism operated in a position inclined to the horizontal.

Drawing