FEEDING DEVICE FOR AN EDGING SAW AND BELONGING FEEDING METHOD

Abstract: Method and device for the feeding of boards (6) to be sawn in an edging sawmill, the device consisting of a feeding device (1) comprising a feed conveyor (3) upon which the boards (6) are fed up to the edging sawmill, a cross conveyor (2) upon which the boards (6) are moved in their cross-direction up to the feed conveyor (3) and a centering device (5) by means of which the boards (6) are put in the desired position on the feed conveyor (3). A lifting device (4) is arranged between the cross conveyor (2) and the feed conveyor (3) by means of which the boards are lifted from a lower position below the level through the upper side of the feed conveyor (3) to an upper position on that level into a holding device (5).

Description: FEEDING DEVICE FOR AN EDGING SAW AND BELONGING FEEDING METHOD- TECHNICAL FIELD The present invention relates to a feeding device for the feeding of boards to be sawn in an edging sawmill comprising a feed conveyor upon which the boards are fed up to the edging sawmill, a cross conveyor upon which the boards are pushed in their cross-direction up to the feed conveyor, and a centring device by means of which the boards are placed in a desired position on the feed conveyor. BACKGROUND TECHNICS Patent applications SE 398 067 and SE 451 188 describe feeding devices for edging mills for wane sawing of pre-sawn boards. The feeding device according to SE 398 067 comprises, as it does in the present invention, a cross conveyor by means of which the boards are conveyed in their cross-direction up to a storing table from which the boards are pushed to a feed conveyor leading to the edging sawmill. A board leaving the cross conveyor is fed onto the storing table by means of a feeding arm situated under the storing table and that when turned, protrudes from the table and pushes the board up to the feed conveyor. By means of a sliding counter-stay the board is centred on this conveyor. A following board can not arrive to the storing table until the previous board has been centred and pushed away. That moment is largely decisive for the capacity of the edging sawmill. Patent application SE 451 188 describes a feeding device where the board is taken from a cross conveyor by means of clamping arms arranged above the feed conveyor and are lifted onto a roller way to be fed into the edging sawmill. Here the action cycle consists in lifting a board and putting it down, releasing it and returning to the next board. It has shown difficult to increase the speed of this action cycle. DESCRIPTION OF THE INVENTION The object of the present invention relates to a feeding device not showing the disadvantages of the above-mentioned known feeding devices. The object is achieved with a feeding device according to the preamble characterized in that a lifting device is arranged between the cross conveyor and the feed conveyor in order to lift the boards from a lower position below the level through the upper side of the feed conveyor to an upper position on that level . A holding device is also arranged to hold a first board in the upper position in the level through the upper side of the feed conveyor. The lifting device is able to take a second board in the position below the first board at the same time as the first board is held in the upper position by means of the holding device. A board arriving from the cross conveyor will then be intermediately stored on the lifting device meanwhile the holding device that also is a centring device pushes the first board onto the feeding conveyor and centres the board upon it to be fed to the edging sawmill. This obtains a saving of time that increases the capacity of the edging sawmill. Further features and characteristics concerning the present invention are evident from the description to the drawings below and from the claims. DESCRIPTION TO THE DRAWINGS The invention is described below as an example of an embodiment in connection with the enclosed drawing showing a feeding device 1 according to the invention connected with a cross conveyor 2 for boards to be sawn in an edging sawmill. The feeding device 1 comprises a feed conveyor 3 connected with a conventional edging sawmill, not shown in the figure, a lifting device 4 by means of which the boards are lifted and a centring device 5 by means of which the boards are centred on the feed conveyor 3. A board 6 to be sawn in the edging sawmill is fed forward at right angles to its longitudinal direction on the cross conveyor 2 up to the feeding device 1 according to the invention where it is lifted up onto a level of the feed conveyor 3 and then pushed onto it and at the same time being centred by means of the centring device 5. The lifting device 4 comprises at least two but preferably more lifters 4.1 parallel in relative position and co-ordinately turnable around a common axis of rotation 4.2. Each lifter 4.1 shows an outer section 4.3 that, when the lifter 4.1 is turned upwards, is on the same level as the level through the supporting surface of the feed conveyor 3 or corresponding members . When turned downwards these sections 4.3 are in direct connection with the end of the cross conveyor 2 and incline diagonally downwards from it. A board 6 that is fed over the end of the cross conveyor 2 passes by itself down onto the outer sections 4.3 of the lifters 4.1 until it jars against a stop member 3.1 on the feed conveyor 3. It lies within the scope of the invention to arrange the lifting device in various ways that however have in common that boards may be put down from the cross conveyor on a level lower than the level through the supporting surface of the feed conveyor. The centring device 5, also a holding device for boards in lifted position, is supported by a frame 5.1 that extends over the feed conveyer 3 and comprises a driving device 5.2 for two swinging arms 5.3 that are turnable around vertical axles and that support vertical clamping members 5.4 at their outer ends. The lower free end of each clamping member 5.4 is provided with ring- shaped slots 5.5 intended to be brought in contact with the long sides of the board 6 which at this sawing stage show so called wanes to be sawn off in the edging sawmill. However, it lies within the scope of the invention to perform those clamping members in several various ways but have in common the ability to keep a board in uplifted position and at the same time push the board onto the feed conveyor 3. In feeding a board 6 to be sawn in an edging sawmill, the board 6 arrives via the cross conveyor 2 to the lifters 4.1, which at that time are in their lower position. As soon as the clamping members 5.4 of the centring device 5 have taken their outer position, that is are put apart so that the board may be taken up between them, the lifters 4.1 are turned upwards until their outer ends 4.3 are on a level with the upper side of the feed conveyor 3. In that position the clamping members 5.4 are made to turn up to each other, the clamping member 5.4, to the right in the figure, pushing the board 6 sideways onto the feed conveyor 3. As the wane of the board 6 always shows a sharp, keen- like edge it is brought to force into one of the slots 5.5 of the clamping member 5.4 whereby the board 6 is kept in raised position partly because one of its sides is resting on the feed conveyor 3 and partly because its other side is held in one of the slots 5.5 of the clamping member 5.4. The lifters 4.1 now may be turned into their lower position to receive an additional board 6, shown dash dotted in the figure, which move is made at the same time as the clamping member 5.4 in the centring device 5 brings the first board 6 into a centred position to be sawn in the edging sawmill. It should be pointed out that the holding and centring device 5 not makes any vertical movement but only shows horizontal lateral movements of the clamping members 5.4. By introducing the boards 6 from underneath and in between the clamping members 5.4 a time consuming movement is avoided and a simplified construction is obtained at the same time as two movements, that is feeding from the cross conveyor 2 and centring on the feed conveyor 3, may be performed at the same time.

Claims: CLAIMS 1. Method for the feeding of boards (6) to be sawn in an edging sawmill by means of a feeding device (1) comprising a cross conveyor (2) upon which the boards (6) are moved in their cross-direction up to a feed conveyor (3) upon which the boards (6) are fed up to the edging sawmill, a holding and centring device (5) by means of which the boards (6) are brought into a desired position on the feed conveyor (3), and a lifting device (4) , arranged between the cross conveyor (2) and the feed conveyor (3) and by means of which the boards are lifted from a position below the level through the upper side of the feed conveyor (3) to an upper position right above that level into the holding and centring device (5) , cha rac t eri zed in that a first board (6) is held in the upper position on the level through the upper side of the feed conveyor (3) by means of a holding and centring device (5) at the same time as the lifting device (4) is brought to receive a second board (6) in the lower position below the first board (6) . 2. Method according to claim 1, charac t e r i zed in that the second board can be brought to slide by itself from the cross conveyor (2) to the lifters (4.1) that are turnable between the lower and the upper position around an axis of rotation (4.2) that is at right angles to the driving direction of the cross conveyor (2) and that shows an outer section (4.3) inclining diagonally downwards from the cross conveyor (2) in the lower position. 3. Feeding device (1) for the feeding of boards (6) to be sawn in an edging sawmill comprising a cross conveyor (2) upon which the boards (6) are moved in their cross direction up to a feed conveyor (3) upon which the boards (6) are fed up to the edging sawmill, a holding and centring device (5) arranged above the feed conveyor (3) by means of which the boards (6) are put in desired position on the feed conveyor (3) and a lifting device (4) arranged between the cross conveyor (2) and the feed conveyor (3) comprising lifting members (4.1) that are movable between the lower and the upper position, each lifting member (4.1) showing a section (4.3) to which a board may be pushed from the cross conveyor (2) in the lower position, charac t e ri zed in that the lifting members are lifters (4.1) that are turnable between the lower and the upper position around an axis of rotation (4.2) that is at right angles to the driving direction of the cross conveyor (2), that each lifter (4.1) shows an outer section (4.3) that inclines diagonally downwards from the cross conveyor (2) in the lower position to which a board may glide by itself from the cross conveyor (2) . 4. Device according to claim 3 , charac t e r i zed in that the holding and centering device (5) comprises two mainly vertical clamping members (5.4) that are movable up to each other and that extend somewhat below the level through the upper side of the feed conveyor (3) . 5. Device according to claim 4, charac t er i zed in that at least one clamping member (5.4) shows a lower end that is provided with a holding members in the shape of slots (5.5) .

Inventors: LOEVKVIST HAAKAN, LOEVKVIST, HAAKAN
Applicants: LOEVKVIST HAAKAN, PARIS TRAE & METALL AB, LOEVKVIST, HAAKAN
Application year: 1998
Main classification: B27B31
IPC codes: B27B31, B65G47