WO1992018301A1

WO1992018301A1 - A method and arrangement for mutually separating boards cut simultaneously in a sawing machine

Info

Publication number: WO1992018301A1
Application number: PCT/SE1992/000233
Authority: WO
Inventors: Lennart Svensson
Original assignee: Ab A K Eriksson
Priority date: 1991-04-12
Filing date: 1992-04-09
Publication date: 1992-10-29
Also published as: SE9101115D0; SE467728B; SE9101115L

Abstract

In a sawing machine which is constructed to cut simultaneously from a log or a block (3) at least two mutually adjacent boards (1, 2), a method for separating said boards one from the other and advancing the boards to downstream board-treating equipment, such as an edging mill. The boards are pressed firmly against the log or the block until the boards have been completely cut therefrom. When the boards (1, 2) have been completely cut from the log or block (3), the outermost board (1) is separated from the log or block with the aid of gripping devices (7) which coact with the outermost board in a manner to release the board (2) that lies inwardly thereof. The outermost board is then released from the gripping devices. The invention also relates to an arrangement for carrying out the inventive method.

Description

A Method and Arrangement for Mutually Separating boards cut simultaneously in a sawing machine.

Machine

The present invention relates to a method of advancing separately at least two mutually adjacent boards cut simultaneously from a log or a block in a sawing ma¬ chine to downstream board treating equipment, said boards being held pressed against the remainder of the log or block until the boards have been completely cut from said log or block. The invention also relates to an arrangement for use when carrying out the method.

When cutting two or more mutually adjacent boards from a log or a block simultaneously in a conventional sawing mill, for instance in a bandsaw mill or a cir¬ cular saw mill, the boards cut from the log or block will be released from the remainder of the log simul¬ taneously and fall down onto an underlying surface, for instance a board conveyor. Subsequent treatment of the boards, for instance in a board edging mill, requires the boards to be introduced manually into the edging mill, one at a time.

It is known to eliminate the necessity of separating the boards manually with the aid of so-called board- separating knives placed in the saw cuts, these knives functioning to deflect the individual boards into different feed paths leading, for instance, to an edging mill.

The use of mechanical barrier devices to ensure that boards which are cut simultaneously from a log will be mutually spaced on a board conveyor has also been

SUBSTITUTES proposed in the art, see for instance SE-B-8302835-7 and FI-B-68373.

The main object of the present invention is to achieve effective separation of the boards without the need for board separating knives or barrier devices, so as to enable the edging mill to be operated unmanned.

This object can be achieved in accordance with the present invention by means of a method of the kind defined in the first paragraph of this specification which is characterized by, subsequent to having cut or sawn the boards from said log or said block, moving each outermost board away from the log or the block with the aid of a respective gripping device which coacts with said outermost board in a manner to release the board lying inwardly thereof and then releasing the outermost board from its gripping device.

In this way, it is possible to mutually separate two boards that have been cut from each side of the log or the block, i.e. four boards in all.

According to one preferred method, each inner board is allowed to fall down onto a board conveyor while the outermost board is held by its gripping device and the outermost board is then placed on the same conveyor by said gripping device at a slightly later point in time. Alternatively, the inner board may be allowed to fall down onto a supporting surface in one position and the outermost board released from said gripping device in another position. The first mentioned method results in a separation in time which can be utilized to achieve a separation in space, whereas the latter method provides a direct spatial separation between the boards. The remaining characteristic features of the inventive method, and also of an arrangement adapted for use in carrying out the method are set forth in the following Claims.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figures 1-4 illustrate an inventive arrangement in its various stages of operation in one working cycle.

By "boards" is meant in the description and Claims of this specification any piece of wood that is cut from a log or like workpiece, irrespective of the dimensions and length of said log.

In the Figures, the reference numeral 3 identifies a log from which two boards 1, 2 are cut from both sides of the log with the aid of a saw (not shown) , for instance a bandsaw or circular saw. As the log 3 is transported past the saw, the log is supported on a conveyor chain 5 and is urged against the chain by means of an overlying wheel or runner 6. Since both the saw and the log feeding arrangement may both be of conventional design, they will not be illustrated or described in detail here.

The boards 1 and 2 cut from the log 3 are held firmly against the remainder of said log by the means of a board pressing device which, in the case of the il- lustrated embodiment, comprises mutually opposing rollers 4, journal means 9 and drive motors 10, which may comprise series-connected hydraulic motors for instance, so that only one drive source is required.

When sawing full-length logs, four pairs of rollers are normally required along the length of the log, said rollers being moveable towards and away from the log in a manner known per se.

The arrangement also includes two mutually opposing gripping devices 7 which coact with the outermost boards 1 cut from opposing sides of the log. ^" In the case of the illustrated embodiment, the gripping de¬ vices 7 are carried by a parallelogram guide means 11, one leg of which is comprised of a hydraulic piston- cylinder device 12. In this case, movement of the gripping devices 7 towards and away from the log is guided by means of a hydraulic piston-cylinder device 14 carried by a schematically illustrated stand 13. The arrangement will preferably include at least three, normally four pairs of gripping devices 7, disposed along the length of the log 3. The gripping devices are suspended in pairs from rails 15, so as to permit a given degree of movement together with the log in the direction of its long axis.

The arrangement further includes a conveyor 8 which is provided with dogging devices 17 and which is able to deliver boards to a conveyor 18 located outside said arrangement. The conveyor 18 functions to convey logs against hooked stops 19 which are used to keep the boards separated from one another, so as to enable the boards to be advanced individually to a downstream edging mill.

Figure 1 shows the arrangement during the actual log sawing operation, in which two boards 1, 2 are cut from opposite sides of the log 3. The boards are held firmly to the log with the aid of the roller-pairs 4. The outermost boards that were cut from the log in a preceding sawing operation are referenced 20 and are shown in abutment with the outermost hooked devices 19 for advancement to a downstream edging mill.

In the Figure 2 illustration, the boards 1, 2 are completely separate from the log 3 and the gripping devices 7 have been displaced into abutment with res¬ pective outer boards 1, with the aid of the piston- cylinder devices 14. In the case of the illustrated embodiment, it is assumed that each gripping device 7 is provided with suction cups which grip the outer boards. While the necessary vacuum in the suction cups is being established, the gripping devices 7 can be caused to accompany movement of the log through a short distance, by moving the suspension devices along the longitudinally extending rails 15.

When the required vacuum has been created, the gripping devices 7 are moved away from the log 3, see Figure 3, and the innermost boards 2 fall down onto the conveyor 8 while guided by a respective board deflecting plate 21, with the outermost boards 1 still held firmly by the gripping devices 7.

The hydraulic piston-cylinder device 12 is then ac¬ tivated to swing respective gripping devices 7 down towards the conveyor 8 and to deliver the boards 1 onto said conveyor, with said boards separated from the innermost board 2, see Figure 4.

The hooks 19, which are located in the vicinity of the outer conveyor 18 (see Figure 1) are controlled so that only one board at a time is advanced in a correct infeed position, in contact with the outer hooked device 19 for feeding the board into a downstream edging mill. It will be noted that as a result of the board deflecting plate 21 and downward swinging of the gripping devices 7 towards the conveyor 8, both boards 1, 2 will be positioned right-way-up, i.e. with the wane edge of the boards facing upwards on the conveyor 8. This positioning of the boards upstream of the following board-edging processing is highly advantag- eous and eliminates the necessity of turning certain boards manually.

As will be understood, the gripping devices 17 may be constructed to deliver the outerboards 1 held thereby in a position which differs from the positions in which the inner boards 2 fall down onto the conveyor 8, as an alternative to the aforedescribed method of delivering said boards on said conveyor, thereby to immediately achieve appropriate spacing between the boards without employing a time delay to deliver the boards on one and the same conveyor, as in the former case.

It will be understood that the described and illus¬ trated preferred embodiments of the invention can be modified in several respects within the scope of the following Claims. This applies primarily to the con¬ struction of the arrangement and to the construction of the gripping devices. For example, hooked devices which coact, e.g. , with the longitudinal edges of the outer boards may be used in addition to suction cups. Furthermore, the gripping devices may also be used as board pressing devices during cutting of the boards from the log, thereby obviating the need for separate pressure rollers or the like. The means for effecting movement of the gripping devices towards and away from the log may also be varied as desired. Furthermore, the gripping devices need only be used when two mutually adjacent boards are cut from the log simul¬ taneously. The gripping devices may optionally be mounted only on one side of the log.

Claims

1. A method of advancing separately to downstream board treating equipment, at least two mutually adja¬ cent boards cut simultaneously from a log or a block in a sawing machine said boards being held pressed against the remainder of the log or block until the boards have been completely cut from said log or block, c h a - r a c t e r i z e d by, subsequent to having cut or sawn the boards from said log or said block, moving each outermost board away from the log or the block with the aid of a respective gripping device which coacts with said outermost board in a manner to release the board lying inwardly thereof and then releasing the outermost board from its gripping device.

2. A method according to Claim 1, c h a r a c ¬ t e r i z e d by allowing the inner board to fall down onto a conveyor and placing the outermost board on the same conveyor with the aid of said gripping devices at a slightly later point in time.

3. A method according to Claim 1, c h a r a c - t e r i z e d by allowing the inner board to fall down onto an underlying surface in one position and by releasing the outermost board from said gripping de¬ vices in another position.

4. A method according to any one of Claims 1-3, c h a r a c t e r i z e d by using gripping devices arranged in pairs on opposite sides of the log or block, for mutually separating four boards cut simul¬ taneously from said log or block.

5. An arrangement for advancing separately at least two mutually adjacent boards (1, 2) cut simultaneously from a log or a block (3) in a sawing machine to down¬ stream board treating equipment, said arrangement being provided with means (4) for holding the boards (1, 2) pressed against the remainder of the log or the block (3) until said boards have been cut completely there¬ from, c h a r a c t e r i z e d in that the arrange¬ ment further includes gripping devices (7) which func¬ tion, subsequent to having completely cut the boards (1, 2) from said log or block, to separate the outer¬ most board (1) from the log or the block so as to release the inwardly-lying board (2) and to thereupon also release the outermost board.

6. An arrangement according to Claim 5, c h a r ¬ a c t e r i z e d in that it includes a conveyor (8) for receiving the inner board (2) ; and in that the gripping devices (7) are intended to place the outer¬ most board (1) on the same conveyor but at a slightly later point in time.

7. An arrangement according to Claim 5, c h r ¬ a c t e r i z e d in that said gripping devices (7) are intended to release the outermost board (1) in a position which differs from the position in which the inner board (2) falls down upon its release.

8. An arrangement according to any one of Claims 5-7, c h a r a c t e r i z e d in that said gripping de- vices (7) are mounted in pairs on opposite sides of the log or the block (3) , so as to enable four boards cut simultaneously from the log or the block to be separa¬ ted one from the other.

9. An arrangement according to any one of Claims 5-8, c h a r a c t e r i z e d in that said gripping de- vices (7) include suction cups which coact with the outer board (1) .

10. An arrangement according to any one of Claims 5-9, c h a r a c t e r i z e d in that said means for holding the boards (1, 2) pressed against the remainder of the log or the block (3) include pressure rollers (4).