EP0418174A1 - Device for dividing elongated pieces of wood into smaller pieces - Google Patents

Abstract

The device comprises a cutting device (1) preceded by a loading conveyor (2). The cutting device (1) comprises two longitudinally offset circular saws (6, 7), associated with a bearing surface (4) and with drive pegs (16) driven by chains (15) housed in longitudinal slots in the bearing surface (4). The bearing surface (4) has an upward slope. The pegs (16) hold the pieces of wood (5) disposed transversely during their sawing by the saws (6, 7). <IMAGE>

Description

The present invention relates to devices for cutting elongated pieces of wood, for example pieces of firewood.

After felling, the pieces of firewood are generally stored in the form of pieces of 1 meter to 2 meters in length. They must then be cut into shorter sections. Preferably, the length of the sections must be less than the size of the stoves in which the wood is intended to be burned.

Generally, the pieces of wood are therefore cut into sections less than 50 centimeters long.

To carry out the flow of pieces of wood to form such sections, one can for example start from a piece of wood 1.20 meters long and cut it into three equal sections of 40 centimeters. According to another example, we start with a piece of wood 1 meter long which we cut into two equal sections of 50 centimeters. We can also start from a two-meter piece of wood, which we cut into five 40-cm sections.

These operations are traditionally carried out by saws, for example by means of circular saws. Known circular saws have a bearing surface on which the timber to be cut can be placed, and a disc-shaped blade rotatably mounted along a transverse axis carried by the frame, the blade being housed in a longitudinal slot in the surface d 'support. A motor drives the saw blade in rotation. The operator must therefore position the piece of wood placed on the support surface parallel to the axis of rotation of the saw, then he must gradually move the piece of wood towards the saw while keeping it parallel to the rotation axis

It is understood that these operations are both tedious and dangerous, and the throughput obtained cannot be significant.

The object of the present invention is in particular to automate the positioning and the driving of the pieces of wood, to bring them from a loading station towards the circular saw (s), to hold the pieces of wood during their cutting, and to evacuate the cut sections.

The difficulty lies in the fact that the pieces of wood to be cut generally have very diverse geometric shapes: the diameter of pieces of firewood can generally be between 5 and 50 centimeters, the diameter not being constant over the entire length of the piece of wood the piece of wood can also be non-linear, include some growths distributed irregularly over the length.

The problem proposed by the present invention is to ensure a correct drive of the pieces of wood, before, during and after their cutting, whatever the geometric irregularities of said pieces of wood, ensuring their correct maintenance for cutting them into sections of determined length. . The drive and the cutting must be done by avoiding as much as possible the jamming of the part on its supports or the saw.

According to another object of the invention, the device, while avoiding jamming as much as possible, however supports without inadmissible deterioration any jamming which may occur in exceptional cases.

According to a particular object of the invention, jamming is especially avoided when it is desired to cut a piece of wood into more than two sections, which requires the use of at least two circular saws; in this case, one must in particular avoid the jamming of one of the two saws, resulting from the presence of the other saw.

The invention has the other advantage of allowing loading in a relatively low position, so that the operator does not have to lift the pieces of wood to introduce them into the device, the introduction being able to be made at relatively low height.

Simultaneously, the device of the invention makes it possible to evacuate the sections in a relatively high position, allowing for example their direct evacuation in a trailer, on a truck or any other means of subsequent evacuation.

The device according to the invention has the further advantage of being very secure, by preventing the user from having direct access to the area occupied by the saw (s).

The device of the invention also makes it possible to significantly increase the flow rate, compared with traditional manual operations.

To reach these and other objects, the the invention comprises a frame comprising a bearing surface on which the timber to be cut can be placed, at least one circular saw blade rotatably mounted along a transverse axis carried by the frame, each blade being housed in a longitudinal saw slot the support surface; rotary drive means ensure the drive of the saw blade for cutting.

According to the invention:
the support surface is inclined longitudinally relative to the horizontal, defining a low inlet end of the support surface and a high outlet end of the support surface,
the bearing surface comprises at least one longitudinal guide slot on either side of each saw slot,
- in each longitudinal guide slot is disposed a continuous guide chain stretched between two end sprockets mounted to rotate according to two transverse rotation shafts, a first end sprocket being disposed in the vicinity of the low surface entry end support, a second end gear being disposed in the vicinity of the upper outlet end of the support surface, the upper strand of guide chain being disposed in the vicinity of the support surface,
chain drive means cause at least one of the transverse rotation shafts to rotate,
- Each chain carries catches, regularly distributed on the chain according to predetermined spacings defining groups of catches aligned transversely, the catches being oriented outside the closed line defined by the chain, so that the catches of the upper strand chain protrude above the bearing surface and can cause in longitudinal translation pieces of wood arranged transversely on the bearing surface,
guiding means are provided for orienting and guiding the tabs during their movement on the bearing surface,
- two side walls and an upper wall surmount the bearing surface to define a cutting compartment in which any projections are retained,
- At least one lateral stop is adapted above the bearing surface, against which can be supported the pieces of wood during longitudinal translation.

According to a particular embodiment, the cleats include nent:
a substantially flat base wall intended to slide on the support surface of the frame, the base wall being of sufficient length to constitute a surface supporting the piece of wood to be cut in a transverse position,
- A rear wall, generally perpendicular to the base wall forming an protruding part of the cleat to drive the piece of wood in longitudinal translation.

The chain drive means advantageously comprise a torque limiting device. In this way, if jamming occurs, the drive is interrupted without damaging the drive members.

• - la figure 1 est une vue de côté, paroi latérale enlevée, de l'ensemble du dispositif selon l'invention ;
• - la figure 2 est une vue de dessus du dispositif de la figure 1 ;
• - la figure 3 est une vue de dessus d'une paroi inférieure de récupération de sciure ;
• - la figure 4 est une vue en bout de la paroi de la figure 3 ;
• - la figure 5 illustre en perspective la structure d'un taquet entraîneur selon l'invention et son association à une chaîne d'entraîne­ment et ;
• - la figure 6 est une vue en bout du dispositif de coupe de la figure 1, vu depuis la sortie du dispositif.

Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the attached figures, among which:

• - Figure 1 is a side view, side wall removed, of the entire device according to the invention;
• - Figure 2 is a top view of the device of Figure 1;
• - Figure 3 is a top view of a lower sawdust recovery wall;
• - Figure 4 is an end view of the wall of Figure 3;
• - Figure 5 illustrates in perspective the structure of a coach cleat according to the invention and its association with a drive chain and;
• - Figure 6 is an end view of the cutting device of Figure 1, seen from the outlet of the device.

In the embodiment shown in the figures, the device according to the invention comprises two main parts, namely the cutting device itself 1, preceded by an input conveyor 2.

We will first describe the cutting device 1 itself.

This device 1 comprises a frame 3 comprising a bearing surface 4 on which the wood 5 to be cut can be placed. The frame 3 carries two circular saw blades 6 and 7 in the form of a disc, mounted to rotate along transverse axes carried by the frame. Each blade is housed in a corresponding longitudinal saw slot made in the bearing surface 4. Rotational drive means, not shown in the figures, rotate the saw blades. These means can be identical to those usually used for driving circular saws. The axes of rotation of the two saws are arranged just below the bearing surface 4.

The bearing surface 4 is inclined longitudinally relative to the horizontal. The longitudinal direction is defined as being perpendicular to the axes of rotation of the saws 6 and 7. The longitudinal inclination of the bearing surface 4 defines a low inlet end 8 of the bearing surface and a high outlet end 9 bearing surface.

The bearing surface includes longitudinal guide slots, on either side of each saw slot. Thus, in Figure 2, there are three longitudinal guide slots 10, 11 and 12: the slots 10 and 11 are arranged on either side of the saw 7, while the slots 11 and 12 are arranged on both sides on the other side of the saw 6.

In each of the longitudinal slots 10, 11 and 12 is disposed a continuous guide chain such that the chain 15, continuous, stretched between two end sprockets 13 and 14 mounted to rotate according to two transverse rotation shafts. The first end pinion 13 is disposed in the vicinity of the lower inlet end 8 of the bearing surface, the second end pinion 14 being disposed in the vicinity of the upper outlet end 9 of the bearing surface . The upper strand 151 of the guide chain 15 is disposed in the vicinity of the bearing surface 4.

Torque limiter chain drive means, not shown in the figures, rotate at least one of the transverse rotation shafts to rotate the chains. The chains are all driven by the same movement. For this, the first end pinions such as the pinion 13 are all mounted on the same transverse input shaft, while the second end pinions such as the pinion 14 are all mounted on the same transverse output shaft, and are thus rotated at the same speed.

Each chain such as the chain 15 carries catches, such as the cleat 16, regularly distributed over the chain according to predetermined spacings. The cleats correspond to one chain to another to define cleat groups aligned transversely. For example, in FIG. 2, there can be seen the cleat 16 of a first chain which is aligned with the cleat 17 of the second chain, itself aligned with the. cleat 18 of the third chain. The cleats are oriented outside the closed line defined by the chain. In this way, the tabs of the upper strand 151 of the chain protrude above the bearing surface 4 and can drive in longitudinal translation pieces of wood such as the piece 5 arranged transversely on the bearing surface 4.

Guiding means are provided to orient and guide the tabs 16 during their movement on the bearing surface 4. For this, according to the embodiment shown in FIG. 5, each cleat comprises a base wall 19 which is substantially flat, intended to slide on the bearing surface 4 of the frame. The base wall 19 has a length L sufficient to constitute a surface supporting the piece of wood 5. The length L must be chosen at least equal to the mean radius of the largest pieces of wood 5 that it is desired to cut with the device . The tabs 16 further comprise a rear wall 20, generally perpendicular to the base wall 19 of which it is integral. The cleat 16 thus forms a right dihedral, as shown in the figure. The upper edge of the rear wall 20 advantageously comprises a rim 21 tending to partially cover a piece of wood 5 which would be disposed on the cleat 16. The cleat 16 is secured to the chain 15 according to a median zone 22 of the base wall 19 , for example by welding or any other means.

The chain 15 comprises links such as the link 23 arranged in a substantially vertical plane, and intermediate links such as the link 24 arranged in an orientation substantially parallel to the bearing surface 4. The vertical links such as the link 23 come flush, by their upper branches, at the bearing surface 4, crossing the slot 10. The intermediate links 24 are housed in lower housings 25 hollowed out on either side of the slot 10 at its base , as shown in the figure. The chain 15 is thus guided in the slot 10, the housings 25 preventing its lifting. The chain 15 thus contributes to maintaining the tabs 16, and opposes their lifting away from the bearing surface 4.

The rear walls 20 of the lugs 16 form protruding parts of lugs to drive the piece of wood 5 in longitudinal translation on the bearing surface 4. A piece of wood 5 is thus held simultaneously by several lugs arranged in a transverse line. The width of the tabs is chosen so that, when passing near the saws, the tabs do not touch the saws.

In the embodiments as shown in which the device comprises two saw blades, it is preferable to offset the saws 6 and 7 longitudinally with respect to each other by a distance E sufficient for each piece of wood 5 to be cut only reaches the second blade 7 after complete flow by the first blade 6. For example, a gap E equal to or greater than the diameter of the saws used is usually necessary. This arrangement prevents the piece of wood from getting caught between the saw blades and blocking the blades.

Two side walls 26 and 27 shown in Figure 2 in top view, and an upper wall 28 shown in side view in Figure 1, surmount the bearing surface 4 to define a cutting compartment 29. The walls avoid any projections of pieces of wood resulting from defective cuts or jamming of the pieces of wood when passing over the saws. One of the side walls 27 also acts as a lateral stop, adapted above the support surface 4, and against which the pieces of wood 5 can be supported during longitudinal translation.

The relative transverse position of the side wall 27 and of the saws 6 and 7 determines the lengths of the cut sections. Advantageously, it is possible to provide means for adjusting the transverse position of the wall 27, in order to define different lengths of sections. The lateral adjustment of the wall 27 also makes it possible to adapt the device to different uses, for example: by bringing the wall 27 closer to position it about 40 centimeters from the saw 6, and by using two saws, it is possible to cut parts 1.20 meters of wood in three 40 cm sections; by moving the wall 27 away so as to place it 50 centimeters from the saw 6, and by using a single saw, pieces of wood of 1 meter can be cut into two sections of 50 centimeters.

For longitudinal guidance, the wall 27 can advantageously include convergent and divergent portions: in FIG. 2, an embodiment is shown in which the wall 27 comprises a convergent inlet portion, followed by a central portion parallel to the guide slots, itself followed by a divergent outlet portion. This arrangement appears favorable to preserve the piece of wood a certain freedom and to avoid its jamming during the cut by the saw.

A retractable inlet flap 30 closes the lower inlet end 8 of the cutting compartment 29. The inlet flap 30 is pivotally mounted on an upper transverse axis 31 between an exhaust position shown in the figure and a position shutter pivoted down. The lower edge of the flap 30 is free to be pushed back and pivoted towards the upper outlet end 9 of the device by the cleats 16 or by the pieces of wood 5 to be cut. The flap 30 thus allows the passage of the cleats and the pieces of wood, and then returns to the closed position. The flap 30 has a double function: firstly, in the closed position, avoiding projections of pieces of wood or debris towards the lower entry end of the device; by its weight and the resistance it opposes to pivoting, it also tends to press the pieces of wood 5 into the bottom of the cleats 16, to improve their positioning by gravity before sawing.

Below the bearing surface 4, there is a bottom wall 32 oriented at an inclination similar to that of the bearing surface 4. The bottom wall 32 occupies at least the entire area disposed under the saws 6 and 7. It thus provides the lower protection of the device. It also ensures the recovery of sawdust produced by cutting the pieces of wood. Indeed, the sawdust falls on the lower wall 32 and, by the inclination of the wall, the sawdust gradually tends to flow towards the lower inlet end 8 and escapes downwards towards an outlet lower sawdust.

The lower wall 32 is advantageously arranged in such a way that the tabs of the lower strand 152 of the chain come to bear slidingly on the lower wall 32. In this way, the tension of the chain is reduced, and a certain amount is thus favored. game of cleats to avoid jamming. In this way, the tabs of the lower chain strand 152 also ensure that the sawdust is drawn towards the lower sawdust outlet.

The longitudinal inclination of the bearing surface 4 is advantageously between 15 and 45 degrees.

FIGS. 3 and 4 show a possible structure of the lower wall 32. In this embodiment, the lower wall 32 comprises upper ribs forming guides for the tabs. For example, the upper ribs 320 and 321 form a channel, the entry of which tapers progressively, into which engage the tabs corresponding to the longitudinal slot 12. This improves the guiding of the tabs, and the evacuation of sawdust. .

In the embodiment shown in FIG. 1, the device further comprises the inlet conveyor 2. The conveyor 2 is of the chain and crossbar type, and has a substantially horizontal loading area 33 without lateral guidance, followed by 'a guiding and centering zone 34 with converging side walls 35 and 36, to bring the pieces of wood in the vicinity of the low entry end 8 on the bearing surface 4. The loading zone 33 of the conveyor d entry 2 is higher than the lower entry end 8 of the bearing surface 4. An inclined plane 37 is provided between the exit of the entry conveyor 2 and the lower entry end 8 of the support 4. The pieces of wood to be cut coming from the conveyor 2 slide by gravity on the inclined plane 37. The inclined plane 37 has a lower part intended to allow the passage of the tabs 16. For example, the lower part of the inclined plane may include lights arranged es in line with the areas occupied by the longitudinal slots 10, 11 and 12. The transverse bars 38 of the conveyor 2 are driven in longitudinal translation by chains 39, the upper ply of bars being driven towards the device 1, by means of drive not shown in the figures.

The present invention may in particular give rise to two particular embodiments. According to a simplified embodiment, the device only comprises a cutting device 1, without an input conveyor 2. The device is then relatively simple. By providing such a device in which the bearing surface 4 is sufficiently long and sufficiently inclined, the lower inlet end 8 can be relatively low to facilitate the introduction of the pieces of wood without having to lift them too high, while the high outlet end 9 can be relatively high, for example at a height sufficient for the sections escaping by l The high outlet end falls into an evacuation device such as a trailer or other vehicle.

According to a more complex embodiment, the cutting device 1 is then associated with an inlet conveyor 2, and can also be associated with an outlet conveyor, not shown, to move the sections cut from the upper outlet end 9 to 'at another outlet end.

The embodiments described above and shown in the figures include two saw blades. It is also possible, according to the invention, to provide a larger number of saw blades, for example 4 or 5 blades, for cutting longer pieces of wood into sections compatible with the admissible lengths in the heating devices.

The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below.

Claims (10)

1 - Device for cutting elongated pieces of wood into sections, comprising:
- a frame (3) comprising a bearing surface (4) on which the wood (5) to be cut can be placed,
at least one circular saw blade (6, 7) rotatably mounted along a transverse axis carried by the frame (3), each blade being housed in a longitudinal saw slot of the bearing surface (4),
- means for driving saw blades in rotation, characterized in that
the support surface (4) is inclined longitudinally with respect to the horizontal, defining a low inlet end (8) of support surface and a high outlet end (9) of support surface,
the bearing surface (4) comprises at least one longitudinal guide slot (10, 11, 12) on either side of each saw slot,
- in each longitudinal guide slot (10, 11, 12) is disposed a continuous guide chain (15) stretched between two end pinions (13, 14) mounted to rotate according to two transverse rotation shafts, a first pinion end (13) being arranged in the vicinity of the lower inlet end (8) of the bearing surface, a second end pinion (14) being arranged in the vicinity of the upper outlet end (9) of surface of support, the upper strand (151) of guide chain (15) being disposed in the vicinity of the support surface (4),
chain drive means cause at least one of the transverse rotation shafts to rotate,
- Each chain (15) carries catch catches (16), regularly distributed over the chain according to predetermined spacings defining groups of catches (16, 17, 18) aligned transversely, the catches being oriented outside the closed line defined by the chain (15), so that the tabs of the upper chain strand (151) protrude above the bearing surface (4) and can cause pieces of wood (5) arranged transversely in longitudinal translation on the bearing surface (4),
guiding means are provided for orienting and guiding the tabs during their movement on the bearing surface (4),
- two side walls (26, 27) and an upper wall (28) surmount the bearing surface (4) to define a cutting compartment (29) in which are retained any projections,
- At least one lateral stop (27) is fitted above the bearing surface (4), against which the pieces of wood (5) can be pressed during longitudinal translation. 2 - Device according to claim 1, characterized in that the tabs (16) comprise:
- a substantially flat base wall (19), intended to slide on the bearing surface (4) of the frame, the base wall being of length (L) sufficient to constitute a surface supporting the piece of wood (5) to cut in a transverse position,
- A rear wall (20), generally perpendicular to the base wall (19) forming an protruding part of the cleat to drive the piece of wood (5) in longitudinal translation. 3 - Device according to one of claims 1 or 2, characterized in that the chain drive means comprise a torque limiting device. 4 - Device according to any one of claims 1 to 3, characterized in that it comprises two circular saw blades (6, 7), interposed in the zones located between three longitudinal slots (10, 11, 12) for guiding . 5 - Device according to claim 4, characterized in that the two blades (6, 7) are offset longitudinally relative to each other by a distance (E) sufficient for each piece of wood (5) to be cut only reaches the second blade (7) after full flow through the first blade (6). 6 - Device according to any one of claims 1 to 5, characterized in that it further comprises a retractable inlet flap (30) closing the lower inlet end (8) of the cutting compartment (29) , the inlet flap (30) being pivotally mounted on an upper transverse axis (31) between a closed position and an exhaust position, its lower edge being free to be pushed back and pivoted towards the end of high outlet (9) by the cleats (16) or the pieces of wood (5) to be cut to allow their passage and then return to the closed position. 7 - Device according to any one of claims 1 to 6, characterized in that it comprises a lower wall (32), disposed below the bearing surface (4) and at a similar inclination, ensuring sawdust recovery and low protection of the device. 8 - Device according to claim 7, characterized in that the lower wall (32) is arranged so that the tabs of the lower strand (152) of chain (15) come to bear slidingly on said lower wall, so that the chain tension (15) is reduced and the tabs drive the sawdust and evacuate it to a lower sawdust outlet. 9 - Device according to any one of claims 1 to 8, characterized in that it further comprises an input conveyor (2) of the chain type (39) and transverse bars (38) comprising a loading area ( 33) substantially horizontal without lateral guiding, followed by a guiding and centering zone (34) with converging side walls (35, 36), to bring the pieces of wood to the lower entry end (8) of the bearing surface (4). 10 - Device according to claim 9, characterized in that:
the loading area (33) of the input conveyor (2) is higher than the lower input end (8) of the bearing surface (4),
- an inclined plane (37) is provided between the output of the input conveyor and the low input end (8) of the bearing surface, inclined plane on which the pieces of wood to be cut slide by gravity in the direction of the low entry (8) of the bearing surface,
- The inclined plane (37) includes lights for the passage of the cleats (16).

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