WO1992000170A1

WO1992000170A1 - Portable saw mill

Info

Publication number: WO1992000170A1
Application number: PCT/SE1991/000460
Authority: WO
Inventors: Ulric MÜLLERN-ASPEGREN
Original assignee: Muellern Aspegren Ulric
Priority date: 1990-06-28
Filing date: 1991-06-25
Publication date: 1992-01-09
Also published as: SE9002284D0; SE468160B; SE9002284L

Abstract

The invention relates to a portable saw mill for sawing of logs and which is intended to be assembled in the close vicinity of the location where the trees are felled. The saw mill comprises a frame (1) with a clamping device for clamping of a log (2) and a long runway rail (10) adapted on the frame (1). A runway carriage (12), on which a power-driven chain saw (21) is fixed, is movably adapted on the runway rail (10). The frame (1) comprises a bottom frame (3), which is intended to rest on the ground with at least two low base girders (4) arranged substantially in parallel and at a distance to each other. The log (2) is intended to rest on the base girders and to be clamped up in the clamping device during the sawing operation. The clamping device comprises at least one fixed stop (15) and at least one tightened, spring-loaded counterstay (16) and the log (2) is adapted to be fed towards the stop between each sawing operation. The stop (15) and counterstay (16) are arranged to steady hold the log (2) along its long sides.

Description

PORTABLE SAW MILL

Field of the invention

The present invention relates to a portable saw mill for sawing of logs. The saw mill is intended to be mounted in the immediate vicinity of the location where the trees have been felled in order that the processing from growing trees to sawn lumber can take place on site without heavy hauling of logs. The saw mill comprises a frame with a clamping device for a log, a long runway rail adapted on the frame and a carriage travelling along the runway rail with a power-driven chain saw mounted on said carriage.

Background of the invention

Logs of dimensions large enough to produce good lumber are, as a rule, too heavy to be moved by hand. Consequently, these logs require various forms of mechanical power for handling and haulage to a stationary sawmill. On a number of occasions it is inconvenient, difficult, or simply impossible to procure the necessary machine power to the location where the trees have been felled. For instance, it may be difficult or impossible for forest machines to get through, something that often happens when the felled forest is located on islands or in other types of terrain where no roads exist. There are also areas so delicate that forest machines are not welcome, due to the devastation of the ground that they cause. Timber may also be available in the vicinity of the place where building will take place, in which case it may be desirable to avoid the costly and unnecessary haulage of timber to a stationary sawmill and/or lumber to the building site. For certain purposes, utilizing special kinds of wood may be of great interest. e.g. types of wood which are not available from lumber yards or which are very expensive. These kinds of wood, such as precious wood, may instead be purchased while growing and be sawn at the location where the tree has been felled. There is also need for processing facilities for very thick logs which the conventional sawmills cannot manage.

Consequently, there is a large need for handling of logs and sawing them into lumber at the location where the tree has been felled. Small, portable saw mills have therefore been developed for this purpose, sawmills which can be assembled on site.

In AT-C-377 219 such a portable saw mill is described, which comprises two bearing stands on which the log is rested and fastened by means of clamping devices, adapted on the stand. On the stands a runway rail is adapted on which a carriage can be moved in the longitudinal direction of the log. A chain saw is mounted on the carriage with the guide bar pointing vertically downwards so that a longi¬ tudinal cut is sawn in the clamped log as the carriage is moved along the runway rail.

Another saw mill, which is designed in a similar way, is shown in DE-A-3 529 100. A number of bearing stands are assembled into a rigid unit by means of a number of longi¬ tudinal girders. Two longitudinal rails are attached to the upper side of the bearing stands and a carriage travels on said rails and on said carriage is mounted a chain saw with the guide bar pointing vertically downwards. The log is lifted up and placed on the bearing stands under the car¬ riage and fastened between two clamping devices at either end of the log.

The known devices are portable but have the disadvantage of being heavy to work and unnecessarily complicated. In both devices some sort of lifting device is needed to enable lifting of the logs up onto the high bearing stands. Since the saw is fixed to the carriage, a sideways shifting of the log is required after that each plank is sawn out of the log. To perform this operation it is necessary, in the known devices, to either first release the log from the clamping devices, move it into the next sawing position and then refasten the log in this position for a new sawing operation, or that the device is equipped with complicated, expensive and heavy mechanical devices for log positioning and shifting into the new sawing position after each cut. In connection with the moving of the log and the clamping in the new sawing position, manual measuring of the new position of the log must be carried out in order that the following plank will have the correct thickness. Further¬ more, the control of the guide bar is insufficient in the known devices, a fact which leads to uneven sawing and poor sawing accuracy.

Summary of the invention

The object of the present invention is to solve the above problems by means of a portable saw mill which is easy to assemble and dismount as well as easy to carry, and which is also rigid, easy to work and which produces high quality lumber.

A device of the type known by way of introduction is, according to the invention, characterized in that during the sawing operation the log is intended to be fastened in the clamping device, which comprises at least one fixed stop and at least one tightened, spring-loaded counterstay, that the log being adapted to be fed towards the stop between each sawing operation and that the stop and σount- erstay are arranged to steady hold the log along its long sides. 4

Additional advantageous features of the invention will be apparent from the following description of embodiments of the invention and from the dependent claims.

The portable saw mill according to the invention comprises a collapsible frame with a detachable runway rail and a carriage with a detachable heavy-duty chain saw. The saw mill can consequently be dismounted as required and trans¬ ported in two, three or four parts, each of which with a weight not exceeding what one person can carry to the location where the lumber is to be sawn.

The frame has a low profile and is made to be placed direct on the ground, which makes it possible to roll the log by hand, using e.g. a spit, onto the low frame. This implies the advantage of enabling one person to manage the sawmill single-handed and without any other mechanical aid than the chain saw.

In the saw mill according to the invention the log's own weight is utilized to fix the jig to the ground, thereby creating stability in the simple frame. This stability is essential to obtain sufficient accuracy in the sawing operation. So the low frame offers the benefits of good stability and manual handling of the logs. By virtue of this design, it is possible to handle logs of thick dimen¬ sions, which produce the best lumber.

The logs are fixed to the frame by means of a clamping device by clamping up the long sides of the log between a number of holding devices, i.e. at least one fixed stop on one long side and at least one counterstay on the other. It is possible to shift the stop on the frame and lock it in different positions, whereby these positions will determine the thickness of the sawn lumber. The counterstay applies a spring-loaded pressure against the log so that the log is constantly pressed against the stop plate. When the stop is locked in one and the same position, all sawn planks will automatically have the same thickness without measuring and adjustment of the log prior to each sawing operation. The absence of time-consuming adjustments implies that the capacity of the saw mill in accordance with the invention will be high.

According to a preferred embodiment of the invention the saw mill is designed with dual guide bar control providing high sawing accuracy and a good quality end product. The dual control is effected by one end of the guide bar being attached directly on the carriage and the other end running along a guiding slot in the frame. In this way, control is obtained both at the upper and the lower ends of the guide bar, resulting in even thickness along the entire length of the plank.

Brief description of the drawings

One embodiment of the device according to the present invention and modifications thereof are described in detail below with reference to the accompanying drawings, wherein

Figure 1 is a side elevation of a mounted saw mill with a log positioned to be sawn,

- Figure 2 is a front elevation of the saw, mill according to Figure 1,

Figure 3 is a top view of the stand without clamping device.

Figure 4 is a detailed side view oi the guide bar.

Figure 5 is a cross-sectional view along the line V-V in Figure 4 with an alter¬ native design of the lower control of the guide bar,

- Figure 6 is a cross-sectional view along the line VI-VI in Figure 1 with an al¬ ternative feeding device for the log.

Figure^~7 is a side elevation of Figure 6.

Detailed description of a preferred embodiment of the invention

In Figures 1 and 2 is shown how the frame (1) is placed on the ground and how a log (2) has been rolled onto the frame. The frame (1) (see Figure 3) comprises a bottom frame (3) with a number of, preferably two, base girders (4) mounted parallel and at a distance in relation to one another, which girders rest on the ground. A number of cross bars (5) are attached to the base girders (4), pre¬ ferably at the outer ends. On the frame (1) are also mounted two longitudinal guiding rails (6), which form between the rails a longitudinal guiding slot (7) in the bottom frame (3). The guiding slot (7) is open between the rails to prevent accumulation of dust during the sawing operation.

At the edge of the bottom frame (3) a number of vertical supports (8) are mounted articulated with the base girders (4) in such a way that the frame can be folded up when the saw mill is dismounted. At the same edge there is also at least one cross strut (9) mounted between the support beam (8) and the cross bar (5), which can be released at one end when the frame is folded up. A runway rail (10), see

Figures 1 and 2 etc., is mounted on top of the supports (8, 9) and comprises two parallel guiding tracks (11). The guiding tracks consist of longitudinal angle bars and on said guiding tracks a carriage (12) is adapted to move along the rails. The two guiding tracks (11) are connected by means of a number of cross bars (13) thus forming a rigid frame.

On the frame (1) a clamping device is adapted to hold the log (2) in a fixed position during the sawing operation. The long sides of the log are fixed between a number of clamping devices comprising at least one fixed stop (15) on one side of the log (2) and at least one spring-loaded counterstay (16) on the other. The fixed stop comprises an adjustable, long holding fixture (14) and, adapted to the holding fixture (14), a support plate (17) bearing against one long side of the log. The stop (15) is shifted on a threaded pin on the support beam (8) , said pin running in a horizontal slot in the holding fixture (14). The stop (15) is locked in the desired position by bracing the holding fixture (14) against the support beam by means of a nut (18) on the threaded pin. By setting the holding fix¬ ture/fixtures (14) at different positions, the distance between the support plate (17) and the saw is adjusted, which in turn determines the thickness of the sawn plank. The counterstay (16), preferably one on each base girder (4), is movable on the base girder and tightened in the direction of the log (2) by means of a rubber tightening device (19). Thus the log (2) is pressed against the stop and the support plate (17) by the counterstay (16).

Between each sawing operation the log can be fed against the stop (15) either manually with the aid of a spit or the like or by means of a feeding device, for instance of the type shown in Figures 6 and 7. In order to make the illu¬ stration clear, only the actual feeding device is shown in these figures, whereby certain details, such as stop and counterstay, have been left out. On one side of either of the base girders (4) one end of a feeding girder (30) is 8 attached to an operating lever (31) by a rotary joint and the other end is attached to a supporting beam (32) by a rotary joint. Operating lever (31) and supporting beam (32) are attached to the base girder ( ) , in such a way that they can rotate around two axles perpendicular to one another (33, 34), enabling the supporting beam to be moved along one plane parallel to the base girder (see Figure 6) as well as moved in one plane perpendicular to the base girder (see Figure 7) . When the lever is brought forward in the direction of the arrow in Figure 6, the feeding girder (30) will move upwards and forwards and will thereby lift the log from the base girder and bring it forwards against the stop (15) (not shown in Figure 6). The operating lever is then brought in the direction of the arrow in Figure 7, i.e. perpendicular to the previous direction, whereby the feeding girder (30) is released from the log. In this extended position the operating lever (31) can be brought back to the initial position (see Figure 6) thus enabling the log to be carried forward once again.

The carriage (12) is movable along the runway rail (10) by means of eight traversing wheels (20), two at each corner of the carriage (12). Each pair of wheels comprises two wheels, arranged perpendicularly, which clasp the outside of the angular guiding tracks (11). In this way, the car¬ riage (12) clasps the guiding tracks (11), thus providing rigidity and high accuracy in the guiding of the saw (21). An extendable locking pin (35) is adapted to the outside of the carriage (12) (see Figure 2) , which locking pin in an extended position runs under the edge of the outer guiding track (11). The locking pin is a safety device which will prevent the carriage from tipping over in case of uneven load.

On the carriage (12) a conventional power-driven chain saw (21) is mounted, which is equipped with a cleaving chain (22), i.e. a chain ground for use in cleaving operations. The saw is attached to the carriage by the guide bar (23) being screwed directly onto the carriage by means of pre¬ ferably two screws (27) through the upper part of the guide bar (23). This attachment implies that perfect control of the upper part of the guide bar is obtained at the same time as it allows great adaptability for use of different types of chain saws. This attachment also facilitates the chain tightening operation.

The lower part of the guide bar (23) is guided along the longitudinal guiding slot (7) between the guiding rails (6) in the bottom frame (3). For this lower guiding control the tip of the guide bar is equipped with sliding blocks (24) on both sides (see Figure 4) which slide along the guiding rails (6) when the saw (21) is moved along the runway rail (10).

In Figure 5 an alternative design is shown of the guiding of the saw tip in the guiding slot (7) between the guiding rails (6). The tip of the guide bar is in this embodiment equipped with a yoke (25) which extends outside the tip in both directions of the slot. At the outer ends of the yoke (25) wheels (26) are adapted, the diameter of which is somewhat smaller than the width of the guiding slot (7) . Thereby the wheels will run on one of the two guiding rails (6) when the carriage is moved.

To facilitate the handling of the heavy log in the frame (1) , a thin slice is initially cut from the log in order to create a flat surface along one long side of the log. Then the log is turned so that the flat side bears against the base girders. In this way the log will rest firmly on the frame whereby the feeding along the base girders is also facilitated.

Modifications of the invention

The invention is by no means limited to the embodiments described above and several possible modifications of the invention are feasible within the scope of the claims. The frame may, for instance, be fitted with one or more addi¬ tional base girders with stops to enable sawing of extra-short logs. The runway rail may also be supplied with an extension with separate ground braces to enable sawing of extra-long planks.

In order to make the sawing operation even more efficient, a number of gauge blocks may be placed on each base girder between the support plate (17) and the log (2) . The thick- ness of the gauge blocks is the same as the desired thick¬ ness of the sawn planks. After each sawing of a plank, said plank will be left in the frame bearing against the log, whereby the following sideways shifting of the log is adjusted by removal of one gauge block at each support plate (17). The handling is further facilitated by the fact that the light gauge blocks are considerably more easy to handle than the long, heavy planks.

Claims

1. Portable saw mill for sawing of logs into planks, which saw mill comprises a frame (1) with a clamping device for fixing of a log (2), a long runway rail (10) adapted to the frame (1) and, adapted to travel along the runway rail (10), a carriage (12) on which a power-driven chain saw (21) is fixed, said frame (1) comprising a bottom frame (3) adapted to rest on the ground with at least two low base girders (4) adapted to carry the log (2) and arranged substantially in parallel and at a distance to each other, characterized in that the log (2) is adapted to be fastened in the clamping device during the sawing operation, that the clamping device comprises at least one fixed stop (15) and at least one tightened, spring-loaded counterstay (16), that the log (2) is adapted to be fed towards the stop between each sawing operation and that the stop (15) and counterstay (16) are arranged to steady hold the log (2) along its long sides.

2. Portable saw mill according to claim 1, character¬ ized in that the fixed stop (15) may be set to different positions on the frame (1) and that said positions will determine the thickness of the planks sawn out of the log.

3. Portable saw mill according to claim 2, character¬ ized in that the runway rail (10) is adapted on support beams (8) which extend vertically from one edge of the bottom frame (3) .

4. Portable saw mill according to claim 3, character¬ ized in that the chain saw (21) is mounted on the runway carriage (12) by attaching the guide bar (23) to the car¬ riage (12) with screws (27) through the upper part of the guide bar.

5. Portable saw mill according to claim 4, character- ized in that a longitudinal guiding slot (7) is arranged in the bottom frame (3), parallel to the runway rail (10) and that the chain saw (21) guide bar (23) is arranged to run in the longitudinal guiding slot (7) when the runway car- riage travels along the runway rail (10).

6. Portable saw mill according to claim 5, character¬ ized in that on opposite sides of the tip of the guide bar (23) sliding blocks (24) -are arranged and that the sliding blocks (24) are arranged to slide along the guiding rails of the longitudinal slot (6) during the sawing operation.

7. Portable saw mill according to claim 5, character¬ ized in that a yoke (25) is arranged on the tip of the guide bar (23) which yoke extends outside the tip of the guide bar in both directions of the guiding slot (7) and which is equipped with a wheel (26) at either end of the yoke (25) and that the diameter of the wheels (26) is somewhat smaller than the width of the slot.

8. Portable saw mill according to claim 1, character¬ ized in that a feeding device is adapted to the frame (1) for feeding of the log (2) along the base girders (4) towards the stop (15) .

9. Portable saw mill according to claim 8, character¬ ized in that the feeding device comprises an operating lever (31) attached to the base girder (4) by means of a rotary joint, said lever being arranged to displace a feeding girder (30) upwards and forwards when performing a rotary motion parallel to the base girder, whereby the log (2) is lifted from the base girder and carried towards the stop (15) .