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(11) | EP 0 929 484 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
A SET-UP FOR FEEDING TIMBER TO A SINGLE-LOG FEEDER ANLAGE ZUM ZUFÜHREN VON BAUMSTÄMMEN ZU EINER VEREINZELEINRICHTUNG ASSEMBLAGE POUR APPORTER DU BOIS A UN DISPOSITIF D'ALIMENTATION D'UNE SEULE PLANCHE DE BOIS A LA FOIS |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to plant for feeding timber boards to and through a single-board feeder in accordance with the preamble of Claim 1. The invention relates in particular to high-speed production plants, i.e. plants in which the boards are fed to different stations at high speeds.
[0002] The timber boards are normally transported in sawmills with their longitudinal axes transversal to the direction of conveyor belt movement. The boards are not distributed uniformly on the belts and the spacings between the boards can vary widely. However, it is desirable to be able to convey the boards in a uniform and regular array, for instance in conjunction with sorting and cross-laying the boards. The boards are advanced with the aid of so-called single-board feeders which grip boards stored temporarily in a buffer region and advance the boards one by one for further handling.
[0003] Because the general aim is to increase the rate of production and therewith the speed at which boards are transported through the plant, it is endeavoured to keep the buffer region upstream of the individual board feeder under control, so that the buffer region will neither be too large nor too small. An excessively large buffer region will result in various kinds of disturbances in operation. For instance, the boards will not remain in contact with the conveyor, but will be pressed up and lifted in the buffer region. If the buffer region is too small or when no boards are present in said region, the feeder will stop. Both instances will immediately result in an interruption in production. Because a high production rate is contingent on the continuous outfeed of boards downstream of the board feeder, the buffer region must be kept constantly full of boards above a given lowest level, wherein the feeder output rate Vut, i.e. the number of boards that are fed out per unit of time multiplied by the width of the board, must be lower than the board feeding speed Vin upstream of the individual board feeder. The buffer region upstream of the board feeder can be said to form a magazine or storage facility and is thus necessary for single-board feeding.
[0004] By utilizing the irregular advancement pattern of the boards on the conveyor to the single-board feeder, with which single-board dispensing of up to three boards per second is possible in single-board feeding operations, the problem presented by the buffer region at high production rates has been solved by the invention, which prevents the buffer region from expanding or decreasing to a lowest level in an uncontrolled manner. This is achieved by virtue of the invention having the characteristic features set forth in the following Claims.
[0005] The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawing, in which the Figure is a schematic side view of a conveyor path on which timber boards are placed cross-wise in the vicinity of a single-board feeder.
[0006] The conveyor belt of the embodiment illustrated in Fig. 1 has the form of a belt conveyor 1 whose board-feeding rate is referenced Vin. The reference numeral 2 identifies a single-board feeder whose board-feeding rate is referenced Vut. Thus, the conveyor 1 moves the boards 4 at the speed Vin, said boards lying cross-wise to the conveying direction. The boards 4 will not normally be distributed regularly on the conveyor 1, but may be spaced unevenly therealong. This is indicated on the left of the Figure. Since the single-board feeder 2 is intended to feed the boards one by one on a forwarding conveyor provided with dogging means, as indicated on the right of the Figure, it is necessary to obtain a given temporary storage or buffer 3 upstream of the single-board feeder. This buffer is obtained by ensuring that Vin is greater than Vut, as earlier indicated. The aforedescribed forms part of the known technology and a more detailed description is thereof unnecessary.
[0007] The invention enables the buffer region 3 upstream of the single-board feeder 2 to be maintained within a controlled size. There is provided upstream of the single-board feeder 2 a regulator which includes endless belts 5 disposed across the width of the conveyor 1, each of said belts being guided over respective guide wheels or rollers 6, of which one is driven. The upper run of the endless belt 5 is located above the upper transporting plane of the conveyor 1 and will thus engage the timber boards 4. As indicated in the drawings, the upper run of the belt 5 shall move in the transporting direction of the conveyor 1. The speed of the belt 5 is Vreg, which is lower than the speed Vin of the conveyor 1. The unevenly distributed boards 4 transported on the conveyor 1 will either be gripped or retarded by the belt 5 as a result of the difference between the speeds Vin and Vreg. Thus, a pre-buffer 3' will be built-up with boards on the upper run of the belt 5 at the same time as the regulator device will deliver the boards that collect thereon in a delayed rate to the conveyor 1 upstream of the single-board feeder 2 when so required by the feeder buffer 3. The pre-buffer 3' can be allowed to grow or expand to a given extent upstream of the regulator. Thus, despite the boards being forwarded to the single-board feeder 2 on the conveyor 1 at the speed Vin, enlargement of the buffer region 3 upstream of the single-board feeder 2 will be equalized in accordance with the timing of the conveyor 1, i.e. an enlargement which keeps within largets and smallest permitted limits. Retardation of the boards and feeding of the boards to the single-board feeder 2 is made possible by utilizing the gaps between the boards on the conveyor 1 upstream of the regulator device. The invention thus enables building-up of the pre-buffer 3' and of the buffer 3 upstream of the single-board feeder 2 to be continued for given shorter periods, even if the feeder 2 is stopped due to a halt in production of the feeder, for instance. The regulator can be constructed to adapt to different speeds of the conveyor 1, and also to different board dimensions and feeder capacities. The regulator speed Vreg will normally lie between Vin and Vut. The invention thus provides a highly flexible arrangement which can be installed in existing plants to solve an existing serious problem, particularly in the case of high-production plants. In principle, the conveyor belts may be of any appropriate kind and made from any suitable material, including high friction chains, provided that they will lower the rate of feed of the boards the speed Vreg.
1. Plant for feeding boards of timber (4) to and through a single-board feeder (2) for
elongated boards of timber (4) which lie sequentially on a conveyor (1) transversely
to the longitudinal axis of said conveyor, wherein the conveyor advances the boards
to the single-board feeder (2) at a speed Vin, said feeder (2) operating at a board-feeding speed Vut that is lower than Vin, characterized by a regulator means (5, 6) mounted upstream of the board feeder (2) and the buffer
region (3) in the proximity thereof as seen in the conveying direction, wherein said
regulator means retards the boards (4) advanced on the conveyor (1) to a speed Vreg which is slower than Vin prior to the boards (4) being conveyed further to the board feeder (2) on the conveyor
(1).
2. Plant according to Claim 1, characterized in that the regulator means comprises high friction endless belts (5) or chains disposed
across the width of the conveyor (1) and each passing over at least two guide wheels
(6), wherein the upper runs of the belts in the regulator means are located above
the conveying plane of the conveyor (1) and move at a speed Vreg which is slower than Vin.
3. Plant according to Claim 1 or 2, characterized in that the speed Vreg of the regulator means is greater than the speed Vut of the single-board feeder (2) but slower than the feeding speed Vin of the conveyor.
4. A method of controlling the feed of timber boards to and through a single-board feeder
(2), wherein the boards are transported to said the single-board feeder (2) in mutually
sequential relationship transversely to the feed direction on a conveyor (1) having
a board-feeding speed Vin, wherein the feeder (2) operates at a board-feeding speed Vut that is slower than Vin, characterized by causing the boards (4) upstream of the single-board feeder (2) and the buffer region
(3) adjacent thereto, as seen in the conveying direction, to move at a speed Vreg which is slower than the speed Vin, prior to forwarding the boards to the single-board feeder (2) on the conveyor (1).
1. Anlage zum Zuführen von Holzbrettern (4) zu und durch eine Einzelbrettzuführung (2)
für längliche Holzbretter (4), welche nacheinander quer zu dessen Längsachse auf einem
Förderer (1) liegen, wobei der Förderer die Bretter mit einer Geschwindigkeit Vin zur Einzelbrettzuführung (2) vorschiebt, welche mit einer Brett-Zuführungsgeschwindigkeit
Vut arbeitet, die niedriger ist als Vin, gekennzeichnet durch ein in Förderrichtung gesehen vor der Brettzuführung (2) und der Pufferzone (3) in
der Nähe derselben angeordnetes Regelmittel (5, 6), wobei das Regelmittel die auf
dem Förderer (1) vorwärts bewegtere Bretter (4) auf eine Geschwindigkeit Vreg verlangsamt, welche langsamer ist als Vin, bevor die Bretter (4) auf dem Förderer (1) zur Brettzuführung (2) weiterbefördert
werden.
2. Anlage nach Anspruch 1, dadurch gekennzeichnet, dass das Regelmittel endlose Bänder (5) oder Ketten mit hoher Reibung enthält, welche
quer über die Breite des Förderers (1) verlaufen und jeweils über mindestens zwei
Führungsrollen (6) laufen, wobei die Obergurte im Regelmittel über der Förderebene
des Förderers (1) liegen und sich mit einer Geschwindigkeit Vreg bewegen, welche niedriger ist als Vin.
3. Anlage nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Geschwindigkeit Vreg der Regelmittel grösser ist als die Geschwindigkeit Vut der Einzelbrettzuführung (2), jedoch niedriger als die Zuführungsgeschwindigkeit
Vin des Förderers.
4. Verfahren zur Steuerung der Zuführung von Holzbrettern zu und durch eine Einzelbrettzuführung
(2), wobei die Bretter nacheinander quer zur Zuführungsrichtung auf einem Förderer
(1) mit einer Brett-Zufuhrgeschwindigkeit Vin zur Einzelbrettzuführung (2) transportiert werden, wobei die Zuführung (2) mit einer
Brett-Zuführungsgeschwindigkeit Vut arbeitet, die niedriger ist als Vin, dadurch gekennzeichnet, dass die Bretter (4) in Förderrichtung gesehen vor der Einzelbrett-Zuführung (2) und der
Pufferzone (3) neben derselben mit einer Geschwindigkeit Vreg bewegt werden, welche langsamer ist als Vin, bevor die Bretter auf dem Förderer (1) zur Einzelbrett-Zuführung (2) weiterbefördert
werden.
1. Installation pour l'alimentation de planches de bois (4) dans et à travers un dispositif
d'alimentation (2) de planches individuelles pour planches de bois allongées (4),
placées de manière séquentielle sur un convoyeur (1) transversalement à l'axe longitudinal
dudit convoyeur, le convoyeur avançant les planches au dispositif d'alimentation (2)
de planches individuelles à une vitesse Vin, et ledit dispositif d'alimentation (2) fonctionnant à une vitesse d'alimentation
Vut qui est inférieure à Vin, caractérisée par un moyen de régulation (5, 6) agencé, vu dans la direction de transport, en amont
du dispositif d'alimentation (2) des planches et de la zone-tampon (3) et à proximité
de celui-ci, ledit moyen de régulation ralentissant les planches (4) avancées sur
le convoyeur (1) à une vitesse Vreg qui est inférieure à Vin avant que les planches (4) ne soient avancées vers le dispositif d'alimentation (2)
des planches sur le convoyeur (1).
2. Installation selon la revendication 1, caractérisée en ce que le moyen de régulation comprend des courroies (5) ou chaînes continues s'étendant
à travers la largeur du convoyeur (1) et passant chacune sur deux rouleaux de guidage
(6) au moins, les brins supérieurs des courroies dans le moyen de régulation étant
situés au-dessus du plan de transport du convoyeur (1) et se déplaçant à une vitesse
Vreg qui est inférieure à Vin.
3. Installation selon la revendication 1 ou 2, caractérisée en ce que la vitesse Vreg du moyen de régulation est supérieure à la vitesse Vut du dispositif d'alimentation (2) de planches individuelles mais inférieure à la vitesse
d'alimentation Vin du convoyeur.
4. Procédé de réglage de l'alimentation de planches de bois dans et à travers un dispositif
d'alimentation (2) de planches individuelles, les planches étant transportées audit
dispositif d'alimentation (2) de planches individuelles de manière séquentielle et
transversalement à la direction d'alimentation sur un convoyeur (1) ayant une vitesse
d'alimentation des planches Vin, le dispositif d'alimentation (2) fonctionnant à une vitesse d'alimentation Vut qui est inférieure à Vin, caractérisé en ce que les planches (4), vu dans la direction de transport et en amont du dispositif d'alimentation
(2) de planches individuelles et de la zone-tampon (3) y adjacente, sont déplacées
à une vitesse Vreg qui est inférieure à la vitesse Vin avant que les planches ne soient avancées vers le dispositif d'alimentation (2) de
planches individuelles sur le convoyeur (1).