EP0002145B1 - Grinding machine with a narrow belt - Google Patents

Grinding machine with a narrow belt Download PDF

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Publication number
EP0002145B1
EP0002145B1 EP78400162A EP78400162A EP0002145B1 EP 0002145 B1 EP0002145 B1 EP 0002145B1 EP 78400162 A EP78400162 A EP 78400162A EP 78400162 A EP78400162 A EP 78400162A EP 0002145 B1 EP0002145 B1 EP 0002145B1
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EP
European Patent Office
Prior art keywords
frame
grinder according
shaft
oscillation
fixed
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Expired
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EP78400162A
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German (de)
French (fr)
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EP0002145A1 (en
Inventor
Jean-Marie Guisez
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Guilliet SA
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Guilliet SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00—Machines or devices using grinding or polishing belts; Accessories therefor
    • B24B21/04—Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces
    • B24B21/10—Machines or devices using grinding or polishing belts; Accessories therefor for grinding plane surfaces involving a rigid member, e.g. pressure bar, table, pressing or supporting the belt over substantially its whole span

Definitions

  • the present invention relates to a narrow belt sanding machine, intended essentially for sanding wooden pieces.
  • a narrow belt sanding machine comprises, in a known manner, a horizontal work table adjustable in height, intended to receive the parts to be sanded, an endless abrasive belt placed above the table transversely to the direction of advance of the parts, suspended between two drums and driven by one of them, and a shoe suspended from a support, capable of pressing on the lower strand of the strip.
  • a more improved sanding machine in which the pressure pad is replaced by a pressure beam which occupies the entire width of the work table and which is controlled by a pneumatic or hydraulic cylinder.
  • Such a machine of course allows very higher feed speeds, but it has the disadvantage that the abrasive belt wears very quickly, because it works continuously over its entire width, and that it undergoes very significant heating, because she doesn't have time to cool down.
  • the object of the invention is to provide a narrow belt sanding machine for industrial production which does not have the drawbacks indicated and which consequently ensures prolonged use and satisfactory cooling of the abrasive belt.
  • the invention therefore relates to a narrow belt sanding machine comprising a frame, a horizontal table, linked to the frame and adjustable in height, for the reception of the pieces to be sanded, two drums, two supports connected to the frame and supporting in rotation these drums, one of the supports comprising a drive motor, an endless abrasive belt stretched between these drums and disposed above the table, and a pressure beam connected to the frame and arranged to press by its lower surface on the lower end of the strip, this machine being characterized in that the drum supports are connected to the frame so as to allow the drums, and therefore the strip, to effect an oscillating movement transverse to the direction of movement of the strip, and the lower surface of the beam has in cross section the shape of an arc centered on the axis of oscillation.
  • the heating is much less violent because only a limited area of the strip is active at a given time, and the other parts of the strip have time to cool.
  • the drum supports are integral with an axis supported in rotation by the frame.
  • the beam is suspended from at least one support integral with said axis.
  • the beam thus performs the same oscillation movement as the strip, which prevents transverse friction between the beam and the abrasive strip from being superimposed on the friction due to the movement of the strip.
  • the sanding machine shown in the drawing comprises a frame 1, a horizontal table 2 carried by the frame for receiving pieces of wood such as B, and a set or sanding head suspended from the frame and which will be described in detail below. -after.
  • Table 2 is not the subject of the present invention, and it will simply be indicated here that it must be adjustable in height so as to accept pieces of wood of different thicknesses.
  • the table is constituted by a drive belt 3 stretched between two drums 4 and moving in the direction of the arrow A to advance the workpiece B under the sanding head.
  • the supports of these drums are adjustable vertically from a flywheel 5 by means not shown.
  • a fixed guide 6 forming a stop for the pieces of wood.
  • many other types of tables can be used, in particular fixed tables associated with rollers for driving wooden pieces, roller tables, air cushion tables, etc.
  • the upper part of the frame is formed by uprights 8 and 9 which carry an axis 10 by means of respective bearings 11 and 12.
  • This axis 10 supports the sanding head consisting of the two drums 20 and 21 between which a band is stretched endless abrasive 22, and a pressure beam 40.
  • the drum 20 is driven in the direction of the arrow C by a motor 23, preferably an electric motor, fixed to a support 24 itself fixed by any means at one end (located on the left in FIG. 1) of the axis 10.
  • the drum 21 is supported in rotation by a support 25 fixed to the other end (situated on the right in FIG. 1) of the axis 10.
  • a cover 28 used to extract the wood dust is fixed to the support 24.
  • the axis 10 is driven in a relatively slow oscillatory movement and of small amplitude by an appropriate drive mechanism, generally designated by 30 and fixed on a part 31 of the frame.
  • the mechanism 30 comprises, in the case shown, a geared motor 32 driving a crank plate 33.
  • a connecting rod 34 is fixed, on the one hand, to the plate 33, on the other hand, at one end of a lever 35 whose l the other end surrounds the axis 10 and is fixed thereto.
  • the rotation of the plate 33 causes an alternating movement of the connecting rod 34 which causes the desired oscillation movement of the lever 35 and of the axis 10, this movement being symbolized by the double arrow in FIG. 3. It should be emphasized however that any mechanism giving the desired oscillation movement could be used.
  • the axis 10 further supports the pressure beam 40 by means of support arms 41 of a particular shape.
  • This beam 40 has the same transverse dimension as the drive belt 3. Its lower surface, which is the surface in contact with the abrasive strip 22a, seen in cross section (cf. FIGS. 2 and 3), the shape of a arc of a circle having its center the center of the axis 10, and therefore remains constantly tangent to the same horizontal plane so that the sanding is carried out by the band 22 in a perfectly regular manner during the above-mentioned oscillation movement.
  • the amplitude of oscillation of the sanding head must be such that the attack of the piece of wood by the abrasive belt occurs correctly for any instantaneous angle of oscillation, in particular in the extreme positions.
  • This condition defines a maximum value which depends on the width of the abrasive strip, or more precisely on the arc defined by the strip.
  • an oscillation of + 8 ° can be expected, with an oscillation period of approximately 1 s.
  • Such an amplitude allows a wood grip (thickness of the material removed) of 1 mm maximum. A larger wood grip can be obtained with a reduced amplitude of oscillation.
  • the extreme positions taken by the support arms 41 during the oscillations are indicated in dashed lines in FIG. 3.
  • the beam 40 carries at its ends rollers 45, 46 used for shaping the strip.
  • rollers are mounted idly on arms 47, 48 fixed to the beam 40 and have a shape such that they always present the strip with a surface identical to that of the beam 40. It is therefore a surface of revolution at constant curvature, which can be seen in FIG. 2.
  • the arms 47, 48 are arranged so that the plane tangent to the lower surface of the beam 40 is also tangent to the rollers 45, 46.
  • These rollers avoid deformation transverse of the strip 22. It should be noted in this regard that the drums 21 and 22 have only a very slight curvature, just necessary to hold the strip in place, and therefore clearly less than that of the lower surface of the beam 40.
  • the support arms 41 which connect the beam 40 to the axis 10 have a C shape, shown in Figure 3, so as to allow passage to the upper strand of the strip 22.
  • the fixing of the beam on the underside arms 41 are carried out in a known manner, for example by screws.
  • the material constituting the beam can be rigid or flexible depending on the requirements. If it is a calibration, i.e. a very precise job, a rigid material must be used, for example steel, wood, plastic, etc. In the case of surfacing, a flexible material such as rubber will be preferable.
  • the lower surface of the beam 40 with a coating of material suitable for friction, for example graphite, to reduce heating caused by the rapid movement of the abrasive strip 22.
  • the speed of movement of the strip 22 is in fact between 15 and 30 m / s.
  • a possibility of adjusting the height of the sanding head is given by the use, for the bearings 11 and 12 carrying the axis 10, of eccentric bearings.
  • the angular position of the bearing 11 can be defined from the adjustment lever 13 via the axis 14 and the connecting rod 15.
  • the angular position of the other bearing 12 is automatically adjusted identically via of the connecting bar 16, which remains blocked by a lever 17 once the adjustment has been made.
  • the adjustment stroke is very limited, for example of the order of 1 mm, but it makes it possible to compensate for the differences in roughness of the abrasive belts. This results in a constant wood grip, whether the strip is fine-grained or coarse-grained.
  • FIG. 4 shows an advantageous alternative embodiment, in which the drive motor 50 of the belt 3 is used to control the oscillation movement of the sanding head.
  • the motor 50 drives the drum 4 by means of a reduction gear 51.
  • the drum 4 is extended on the side opposite to the drive by a shaft 52 on which a crank 53 is fixed. Towards the end of the latter is pivotally mounted a connecting rod 54 also pivotally mounted at its other end on a lever 55 fixed to the support arm 41.
  • the rotation of the drum 4 while driving the belt will cause a continuous oscillation movement of the head sanding.
  • This embodiment has the advantage of not requiring a particular motor for controlling the oscillation.
  • the connecting rod 54 and the lever 55 are placed in the interval which separates the belt 3 from the upright of the frame.
  • the invention is not limited to the embodiments described. Thus, one could provide, instead of automatic control, manual control of the oscillation movement. It would suffice in this case to attach a lever such as the lever 55 of FIG. 4 to the support arm 41 and to mount at the lower end of this lever an operating handle moving in a slot or light passing through the upright of the frame and having the shape of an arc centered on the axis of oscillation.
  • Means may also be provided for blocking the lever in a given position, for example a threaded rod fixed on the lever in the vicinity of the handle and also engaged in the aforementioned slot, and a nut screwed onto the threaded rod, which can be tightened against the upright of the frame to immobilize the lever.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Description

La présente invention concerne une machine à poncer à bande étroite, destinée essentiellement au ponçage de pièces de bois.The present invention relates to a narrow belt sanding machine, intended essentially for sanding wooden pieces.

Une machine à poncer à bande étroite comprend de façon connue une table de travail horizontale réglable en hauteur, destinée à recevoir les pièces à poncer, une bande abrasive sans fin disposée au-dessus de la table transversalement à la direction d'avance des pièces, suspendue entre deux tambours et entraînée par l'un d'eux, et un patin suspendu à un support, susceptible de presser sur le brin inférieur de la bande.A narrow belt sanding machine comprises, in a known manner, a horizontal work table adjustable in height, intended to receive the parts to be sanded, an endless abrasive belt placed above the table transversely to the direction of advance of the parts, suspended between two drums and driven by one of them, and a shoe suspended from a support, capable of pressing on the lower strand of the strip.

Dans une version artisanale d'une telle machine, un opérateur déplace le patin de pression de façon appropriée suivant la largeur de la pièce, de façon à obtenir un ponçage régulier. Mais la vitesse d'avance des pièces est beaucoup trop réduite pour satisfaire aux exigences de la production industrielle.In an artisanal version of such a machine, an operator moves the pressure pad appropriately according to the width of the part, so as to obtain a regular sanding. But the feed speed of the parts is much too reduced to meet the requirements of industrial production.

On connaît également une machine à poncer plus perfectionnée, dans laquelle le patin de pression est remplacé par une poutre de pression qui occupe toute la largeur de la table de travail et qui est commandée par un vérin pneumatique ou hydraulique.A more improved sanding machine is also known, in which the pressure pad is replaced by a pressure beam which occupies the entire width of the work table and which is controlled by a pneumatic or hydraulic cylinder.

Une telle machine permet bien entendu des vitesses d'avance très supérieures, mais elle présente l'inconvénient que la bande abrasive s'use très vite, car elle travaille en permanence sur toute sa largeur, et qu'elle subit un échauffement très important, car elle n'a pas le temps de se refroidir.Such a machine of course allows very higher feed speeds, but it has the disadvantage that the abrasive belt wears very quickly, because it works continuously over its entire width, and that it undergoes very significant heating, because she doesn't have time to cool down.

L'invention a pour but de procurer une machine à poncer à bande étroite de production industrielle, qui ne présente pas les inconvénients signalés et qui assure par conséquent un usage prolongé et un refroidissement satisfaisant de la bande abrasive.The object of the invention is to provide a narrow belt sanding machine for industrial production which does not have the drawbacks indicated and which consequently ensures prolonged use and satisfactory cooling of the abrasive belt.

L'invention a donc pour objet une machine à poncer à bande étroite comprenant un bâti, une table horizontale, liée au bâti et réglable en hauteur, pour la réception des pièces à poncer, deux tambours, deux supports reliés au bâti et supportant en rotation ces tambours, l'un des supports comportant un moteur d'entraînement, une bande abrasive sans fin tendue entre ces tambours et disposée au-dessus de la table, et une poutre de pression reliée au bâti et agencée pour presser par sa surface inférieure sur le brin inférieur de la bande, cette machine étant caractérisée par le fait que les supports de tambour sont reliés au bâti de façon à permettre aux tambours, et donc à la bande, d'effecteur un mouvement d'oscillation transversal à la direction de déplacement de la bande, et la surface inférieure de la poutre présente en section transversale la forme d'un arc de cercle centré sur l'axe d'oscillation.The invention therefore relates to a narrow belt sanding machine comprising a frame, a horizontal table, linked to the frame and adjustable in height, for the reception of the pieces to be sanded, two drums, two supports connected to the frame and supporting in rotation these drums, one of the supports comprising a drive motor, an endless abrasive belt stretched between these drums and disposed above the table, and a pressure beam connected to the frame and arranged to press by its lower surface on the lower end of the strip, this machine being characterized in that the drum supports are connected to the frame so as to allow the drums, and therefore the strip, to effect an oscillating movement transverse to the direction of movement of the strip, and the lower surface of the beam has in cross section the shape of an arc centered on the axis of oscillation.

Du fait de ce mouvement d'oscillation, l'usure se répartit sur toute la largeur de la bande abrasive.Due to this oscillating movement, the wear is distributed over the entire width of the abrasive belt.

En outre, l'échauffement est beaucoup moins violent car seule une zone limitée de la bande est active à un instant donné, et les autres parties de la bande ont le temps de se refroidir.In addition, the heating is much less violent because only a limited area of the strip is active at a given time, and the other parts of the strip have time to cool.

Dans une forme de réalisation préférée, les supports de tambour sont solidaires d'un axe supporté en rotation par le bâti.In a preferred embodiment, the drum supports are integral with an axis supported in rotation by the frame.

De préférence, la poutre est suspendue à au moins un support solidaire du dit axe. La poutre exécute ainsi le même mouvement d'oscillation que la bande, ce qui évite qu'un frottement transversal entre la poutre et la bande abrasive se superpose au frottement dû au déplacement de la bande.Preferably, the beam is suspended from at least one support integral with said axis. The beam thus performs the same oscillation movement as the strip, which prevents transverse friction between the beam and the abrasive strip from being superimposed on the friction due to the movement of the strip.

L'invention sera bien comprise à la lecture de la description suivante, faite en se référant au dessin annexé sur lequel:

  • - la figure 1 est une vue en élévation frontale simplifiée d'une machine à poncer selon l'invention;
  • - la figure 2 est une vue de profil de la machine de la figure 1, certaines parties n'étant par représentées;
  • - la figure 3 est une vue en coupe selon la ligne a-a de la figure 1, et
  • - la figure 4 illustre une variante cie réalisation avantageuse.
The invention will be clearly understood on reading the following description, made with reference to the appended drawing in which:
  • - Figure 1 is a simplified front elevational view of a sanding machine according to the invention;
  • - Figure 2 is a side view of the machine of Figure 1, some parts not being shown;
  • FIG. 3 is a sectional view along the line aa in FIG. 1, and
  • - Figure 4 illustrates a variant cie advantageous embodiment.

La machine à poncer représentée sur le dessin comprend un bâti 1, une table horizontale 2 portée par le bâti pour la réception de pièces de bois telles que B, et un ensemble ou tête de ponçage suspendu au bâti et qu'on décrira en détail ci-après.The sanding machine shown in the drawing comprises a frame 1, a horizontal table 2 carried by the frame for receiving pieces of wood such as B, and a set or sanding head suspended from the frame and which will be described in detail below. -after.

La table 2 n'est pas l'objet de la présente invention, et on indiquera simplement ici qu'elle doit être réglable en hauteur de façon à admettre des pièces de bois de différentes épaisseurs. Dans le cas représenté, la table est constituée par un tapis d'entraînement 3 tendu entre deux tambours 4 et se déplaçant dans le sens de la flèche A pour faire avancer la pièce B sous la tête de ponçage. Les supports de ces tambours sont réglables verticalement à partir d'un volant 5 par des moyens non représentés. De plus, il est prévu un guide fixe 6 formant butée pour les pièces de bois. On peut toutefois utiliser bien d'autres types de tables, notamment des tables fixes associées à des galets d'entraînement des pièces de bois, des tables à rouleaux, à coussin d'air, etc.Table 2 is not the subject of the present invention, and it will simply be indicated here that it must be adjustable in height so as to accept pieces of wood of different thicknesses. In the case shown, the table is constituted by a drive belt 3 stretched between two drums 4 and moving in the direction of the arrow A to advance the workpiece B under the sanding head. The supports of these drums are adjustable vertically from a flywheel 5 by means not shown. In addition, there is provided a fixed guide 6 forming a stop for the pieces of wood. However, many other types of tables can be used, in particular fixed tables associated with rollers for driving wooden pieces, roller tables, air cushion tables, etc.

La partie supérieure du bâti est formée par des montants 8 et 9 qui portent un axe 10 par l'intermédiaire de paliers respectifs 11 et 12. Cet axe 10 supporte la tête de ponçage constituée des deux tambours 20 et 21 entre lesquels est tendue une bande abrasive sans fin 22, et d'une poutre de pression 40.The upper part of the frame is formed by uprights 8 and 9 which carry an axis 10 by means of respective bearings 11 and 12. This axis 10 supports the sanding head consisting of the two drums 20 and 21 between which a band is stretched endless abrasive 22, and a pressure beam 40.

Le tambour 20 est entraîné dans le sens de la flèche C par un moteur 23, de préférence un moteur électrique, fixé à un support 24 lui- même fixé par un moyen quelconque à une extrémité (située à gauche sur la figure 1) de l'axe 10. Le tambour 21 est supporté en rotation par un support 25 fixé à l'autre extrémité (située à droite sur la figure 1 ) de l'axe 10.The drum 20 is driven in the direction of the arrow C by a motor 23, preferably an electric motor, fixed to a support 24 itself fixed by any means at one end (located on the left in FIG. 1) of the axis 10. The drum 21 is supported in rotation by a support 25 fixed to the other end (situated on the right in FIG. 1) of the axis 10.

En outre, un capot 28 servant à aspirer la poussière de bois est fixé au support 24.In addition, a cover 28 used to extract the wood dust is fixed to the support 24.

L'axe 10 est animé d'un mouvement d'oscillation relativement lent et de faible amplitude par un mécanisme d'entraînement approprié, désigné dans son ensemble par 30 et fixé sur une partie 31 du bâti.The axis 10 is driven in a relatively slow oscillatory movement and of small amplitude by an appropriate drive mechanism, generally designated by 30 and fixed on a part 31 of the frame.

Le mécanisme 30 comprend, dans le cas représenté, un motoréducteur 32 entraînant un plateau-manivelle 33. Une bielle 34 est fixée, d'une part, au plateau 33, d'autre part, à une extrémité d'un levier 35 dont l'autre extrémité entoure l'axe 10 et y est fixée. La rotation du plateau 33 provoque un mouvement alternatif de la bielle 34 qui entraîne le mouvement d'oscillation souhaité de levier 35 et de l'axe 10, ce mouvement étant symbolisé par la double flèche de la figure 3. Il faut souligner toutefois qu'on pourrait utiliser tout mécanisme donnant le mouvement d'oscillation désiré.The mechanism 30 comprises, in the case shown, a geared motor 32 driving a crank plate 33. A connecting rod 34 is fixed, on the one hand, to the plate 33, on the other hand, at one end of a lever 35 whose l the other end surrounds the axis 10 and is fixed thereto. The rotation of the plate 33 causes an alternating movement of the connecting rod 34 which causes the desired oscillation movement of the lever 35 and of the axis 10, this movement being symbolized by the double arrow in FIG. 3. It should be emphasized however that any mechanism giving the desired oscillation movement could be used.

L'axe 10 supporte en outre la poutre de pression 40 par l'intermédiaire de bras-supports 41 de forme particulière. Cette poutre 40 a la même dimension transversale que le tapis d'entraînement 3. Sa surface inférieure, qui est la surface en contact avec la bande abrasive 22a, vue en section transversale (cf. figures 2 et 3), la forme d'un arc de cercle ayant pour centre le centre de l'axe 10, et reste donc constamment tangente au même plan horizontal si bien que le ponçage est effectué par la bande 22 d'une manière parfaitement régulière au cours du mouvement d'oscillation précité.The axis 10 further supports the pressure beam 40 by means of support arms 41 of a particular shape. This beam 40 has the same transverse dimension as the drive belt 3. Its lower surface, which is the surface in contact with the abrasive strip 22a, seen in cross section (cf. FIGS. 2 and 3), the shape of a arc of a circle having its center the center of the axis 10, and therefore remains constantly tangent to the same horizontal plane so that the sanding is carried out by the band 22 in a perfectly regular manner during the above-mentioned oscillation movement.

L'amplitude d'oscillation de la tête de ponçage doit être telle que l'attaque de la pièce de bois par la bande abrasive se produise correctement pour tout angle instantané d'oscillation, en particulier dans les positions extrêmes. Cette condition définit une valeur maximale qui dépend de la largeur de la bande abrasive, ou plus précisément de l'arc défini par la bande. En pratique, on peut prévoir une oscillation de + 8°, avec une période d'oscillation d'environ 1 s. Une telle amplitude permet une prise de bois (épaisseur de la matière enlevée) de 1 mm au maximum. Une prise de bois plus importante peut être obtenue avec une amplitude d'oscillation réduite. Les positions extrêmes prises par les bras-supports 41 au cours des oscillations sont indiquées en trait mixte à la figure 3.The amplitude of oscillation of the sanding head must be such that the attack of the piece of wood by the abrasive belt occurs correctly for any instantaneous angle of oscillation, in particular in the extreme positions. This condition defines a maximum value which depends on the width of the abrasive strip, or more precisely on the arc defined by the strip. In practice, an oscillation of + 8 ° can be expected, with an oscillation period of approximately 1 s. Such an amplitude allows a wood grip (thickness of the material removed) of 1 mm maximum. A larger wood grip can be obtained with a reduced amplitude of oscillation. The extreme positions taken by the support arms 41 during the oscillations are indicated in dashed lines in FIG. 3.

La poutre 40 porte à ses extrémités des galets 45, 46 servant à la mise en forme de la bande. Ces galets sont montés fous sur des bras 47, 48 fixés à la poutre 40 et ont une forme telle qu'ils présentent toujours à la bande une surface identique à celle de la poutre 40. Il s'agit donc d'une surface de révolution à courbure constante, que l'on peut voir sur la figure 2. Les bras 47, 48 sont disposés de façon que le plan tangent à la surface inférieure de la poutre 40 soit également tangent aux galets 45, 46. Ces galets évitent une déformation transversale de la bande 22. Il faut préciser à ce sujet que les tambours 21 et 22 ne présentent qu'une courbure très légère, juste nécessaire au maintien en place de la bande, et donc nettement inférieure à celle de la surface inférieure de la poutre 40.The beam 40 carries at its ends rollers 45, 46 used for shaping the strip. These rollers are mounted idly on arms 47, 48 fixed to the beam 40 and have a shape such that they always present the strip with a surface identical to that of the beam 40. It is therefore a surface of revolution at constant curvature, which can be seen in FIG. 2. The arms 47, 48 are arranged so that the plane tangent to the lower surface of the beam 40 is also tangent to the rollers 45, 46. These rollers avoid deformation transverse of the strip 22. It should be noted in this regard that the drums 21 and 22 have only a very slight curvature, just necessary to hold the strip in place, and therefore clearly less than that of the lower surface of the beam 40.

Les bras-supports 41 qui relient la poutre 40 à l'axe 10 ont une forme en C, représentée à la figure 3, de manière à laisser le passage au brin supérieur de la bande 22. La fixation de la poutre sur la face inférieure des bras 41 s'effectue de façon connue, par exemple par des vis.The support arms 41 which connect the beam 40 to the axis 10 have a C shape, shown in Figure 3, so as to allow passage to the upper strand of the strip 22. The fixing of the beam on the underside arms 41 are carried out in a known manner, for example by screws.

La matière constituant la poutre peut être rigide ou souple suivant les exigences. S'il s'agit d'un calibrage, c'est-à-dire d'un travail très précis, il faut utiliser une matiére rigide, par exemple de l'acier, du bois, une matière plastique, etc. S'il s'agit d'un surfaçage, une matière souple telle qu'un caoutchouc sera préférable.The material constituting the beam can be rigid or flexible depending on the requirements. If it is a calibration, i.e. a very precise job, a rigid material must be used, for example steel, wood, plastic, etc. In the case of surfacing, a flexible material such as rubber will be preferable.

En outre, on prévoit avantageusement de munir la surface inférieure de la poutre 40 d'un revêtement en matière adaptée au frottement, par exemple en graphite, pour réduire réchauffement provoqué par le déplacement rapide de la bande abrasive 22. La vitesse de déplacement de la bande 22 se situe en effet entre 15 et 30 m/s.In addition, it is advantageous to provide the lower surface of the beam 40 with a coating of material suitable for friction, for example graphite, to reduce heating caused by the rapid movement of the abrasive strip 22. The speed of movement of the strip 22 is in fact between 15 and 30 m / s.

En résumé, grâce au mouvement d'oscillation de l'ensemble de la tête de ponçage et à la forme appropriée de la poutre 40, on obtient un allongement très important de la durée de vie d'une bande, puisque l'usure est répartie sur toute la largeur de la bande. Comme la partie en contact avec le bois ne représente qu'une petite fraction de la bande, on obtient l'avantage supplémentaire que les parties non en contact peuvent se refroidir, ce qui limite l'échauffement et augmente la durée de vie de la bande. En outre, grâce à la courbure de la poutre 40, l'engagement de la pièce de bois s'effectue sans aucun problème, ce qui permet des avances de pièce rapides.In summary, thanks to the oscillation movement of the entire sanding head and the appropriate shape of the beam 40, a very significant lengthening of the life of a strip is obtained, since the wear is distributed across the width of the strip. As the part in contact with the wood represents only a small fraction of the strip, we obtain the additional advantage that the parts not in contact can cool, which limits heating and increases the life of the strip. . In addition, thanks to the curvature of the beam 40, the engagement of the piece of wood is carried out without any problem, which allows rapid piece advances.

D'autre part, une possibilitié de réglage en hauteur de la tête de ponçage est donnée par l'utilisation, pour les paliers 11 et 12 portant l'axe 10, de paliers à excentrique. La position angulaire du palier 11 peut être définie à partir du levier de réglage 13 par l'intermédiaire de l'axe 14 et de la bielle 15. La position angulaire de l'autre palier 12 est réglée automatiquement de façon identique par l'intermédiaire de la barre de liaison 16, qui reste bloquée par un levier 17 une fois le réglage effectué.On the other hand, a possibility of adjusting the height of the sanding head is given by the use, for the bearings 11 and 12 carrying the axis 10, of eccentric bearings. The angular position of the bearing 11 can be defined from the adjustment lever 13 via the axis 14 and the connecting rod 15. The angular position of the other bearing 12 is automatically adjusted identically via of the connecting bar 16, which remains blocked by a lever 17 once the adjustment has been made.

La course de réglage est très limitée, par exemple de l'ordre de 1 mm, mais elle permet de compenser les différences de rugosité des bandes abrasives. On obtient ainsi une prise de bois constante, que la bande soit à grain fin ou à grain grossier.The adjustment stroke is very limited, for example of the order of 1 mm, but it makes it possible to compensate for the differences in roughness of the abrasive belts. This results in a constant wood grip, whether the strip is fine-grained or coarse-grained.

Ce réglage fin est particulièrement intéressant dans le cas d'une machine à plusieurs bandes juxtaposées effectuant des ponçages de plus en plus fins d'une même pièce de bois. Le réglage précité permet alors de compenser la finesse croissante des bandes. On a représenté à la figure 4 une variante de réalisation avantageuse, dans laquelle on utilise le moteur d'entraînement 50 du tapis 3 pour commander le mouvement d'oscillation de la tête de ponçage.This fine adjustment is particularly advantageous in the case of a several juxtaposed bands carrying out increasingly fine sandings of the same piece of wood. The aforementioned adjustment then makes it possible to compensate for the increasing fineness of the bands. FIG. 4 shows an advantageous alternative embodiment, in which the drive motor 50 of the belt 3 is used to control the oscillation movement of the sanding head.

Le moteur 50 entraîne le tambour 4 par l'intermédiaire d'un réducteur 51. Le tambour 4 se prolonge du côté opposé à l'entraînement par un arbre 52 sur lequel est calée une manivelle 53. Vers l'extrémité de celle-ci est montée pivotante une bielle 54 également montée pivotante à son autre extrémité sur un levier 55 fixé au bras-support 41.The motor 50 drives the drum 4 by means of a reduction gear 51. The drum 4 is extended on the side opposite to the drive by a shaft 52 on which a crank 53 is fixed. Towards the end of the latter is pivotally mounted a connecting rod 54 also pivotally mounted at its other end on a lever 55 fixed to the support arm 41.

Comme le bras-support 41 est solidaire de l'axe 10, auquel sont également fixés les supports de tambour non représentés ici, la rotation du tambour 4, tout en entraînant le tapis, va provoquer un mouvement d'oscillation continu de la tête de ponçage.As the support arm 41 is integral with the axis 10, to which are also attached the drum supports not shown here, the rotation of the drum 4, while driving the belt, will cause a continuous oscillation movement of the head sanding.

Cette réalisation a l'avantage de ne pas nécessiter un moteur particulier pour la commande de l'oscillation.This embodiment has the advantage of not requiring a particular motor for controlling the oscillation.

En ce qui concerne la disposition des différents éléments dans cette variante, on indiquera que, comme le montre d'ailleurs la figure 4, la bielle 54 et le levier 55 sont placés dans l'intervalle qui sépare le tapis 3 du montant du bâti. L'invention n'est pas limitée aux formes de réalisation décrites. Ainsi, on pourrait prévoir, à la place de la commande automatique, une commande manuelle du mouvement d'oscillation. Il suffirait dans ce cas de fixer un levier tel que le levier 55 de la figure 4 au bras-support 41 et de monter à l'extrémité inférieure de ce levier une poignée de manoeuvre se déplaçant dans une fente ou lumière traversant le montant du bâti et présentant la forme d'un arc de cercle centré sur l'axe d'oscillation. Une action sur la poignée provoquera ainsi un déplacement de la tête de ponçage, le mouvement étant communiqué aux supports de tambour par l'intermédiaire de l'axe 10 comme dans la réalisation de la figure 4. On pourra prévoir en outre un moyen pour bloquer le levier dans une position donnée, par exemple une tige filetée fixée sur le levier au voisinage de la poignée et également engagée dans la lumière précitée, et un écrou vissé sur la tige filetée, qu'on pourra serrer contre le montant du bâti pour immobiliser le levier.With regard to the arrangement of the various elements in this variant, it will be indicated that, as also shown in FIG. 4, the connecting rod 54 and the lever 55 are placed in the interval which separates the belt 3 from the upright of the frame. The invention is not limited to the embodiments described. Thus, one could provide, instead of automatic control, manual control of the oscillation movement. It would suffice in this case to attach a lever such as the lever 55 of FIG. 4 to the support arm 41 and to mount at the lower end of this lever an operating handle moving in a slot or light passing through the upright of the frame and having the shape of an arc centered on the axis of oscillation. An action on the handle will thus cause a displacement of the sanding head, the movement being communicated to the drum supports via the axis 10 as in the embodiment of FIG. 4. Means may also be provided for blocking the lever in a given position, for example a threaded rod fixed on the lever in the vicinity of the handle and also engaged in the aforementioned slot, and a nut screwed onto the threaded rod, which can be tightened against the upright of the frame to immobilize the lever.

Claims (11)

1. Narrow belt grinder comprising a frame (1), a horizontal table (2) connected to the frame (1) and adjustable in height, for receiving pieces (B) to be ground, two drums (20, 21), two supports (24, 25) connected to the frame (1) and supporting these drums (20, 21) in rotation, one of the supports (24, 25) comprising a drive motor (23), an endless abrasive belt (22) stretched between these drums (20, 21) and disposed above the table, and a pressure beam (40) connected to the frame (1) and arranged for its lower surface to press on the lower side of the belt, characterised in that the drum supports (24, 25) are connected to the frame (1) so as to allow the drums (20, 21) and therefore the abrasive belt (22), to make a movement of oscillation transverse with respect to the direction of displacement of the abrasive belt (22), and the transverse section of the lower surface of the pressure beam (40) is in the form of an arc of circle centred on the axis of oscillation.
2. Grinder according to Claim 1, characterised in that the drum supports (24, 25) are fast with a shaft (10) supported in rotation by the frame (1).
3. Grinder according to Claim 2, characterised in that the shaft (10) is animated by a movement of oscillation by a drive mechanism (30) fixed to the frame (1).
4. Grinder according to Claim 3, characterised in that the mechanism (30) for driving the shaft (10) comprises a motor reduction gear (32) fixed to the frame (1), a disc-crank (33) and connecting rod (34) assembly driven by the motor reduction gear (32) and a lever (35) fast with the shaft (10) and fixed to the free end of the connecting rod (34).
5. Grinder according to Claim 2, characterised in that the pressure beam (40) is suspended from at least one support arm (41) fast with said shaft (10).
6. Grinder according to Claim 5, characterised in that said support arm or arms (41) are in the form of a C so as to allow the passage of the upper side of the abrasive belt (22).
7. Grinder according to one of Claims 1 to 6, characterised in that idle rollers (45, 46) are fixed to the pressure beam (40) on either side thereof, in the direction of displacement of the abrasive belt (22), said rollers (45, 46) having the same curvature as the lower surface of the pressure beam (40).
8. Grinder according to Claim 5, characterised in that it comprises a lever (35, 55) fixed to one of the support arms (41) for pressure beam (40) by one end and adapted to be driven by the other end to cause a movement of oscillation of the support arm or arms (41) for pressure beam (40) and of the drum supports (24, 25) fast with the shaft (10).
9. Grinder according to Claim 8, in which the receiving table (2) is constituted by an endless belt (3) mobile between a driving drum (4) and a driven drum, characterised in that a crank (53) is fixed on the shaft (52) of the driving drum (4) and a connecting rod (54) connects the respective ends of the lever (55) and the crank (53).
10. Grinder according to Claim 8, characterised in that the free end of the lever (55) bears a handle engaged in a slot made in the frame and having the form of an arc of circle centred on the axis of oscillation (10).
11. Grinder according to Claim 5, in which the shaft (10) is mounted to rotate in eccentric bearings.
EP78400162A 1977-11-14 1978-11-02 Grinding machine with a narrow belt Expired EP0002145B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7734173A FR2408428A1 (en) 1977-11-14 1977-11-14 NARROW BELT SANDING MACHINE
FR7734173 1977-11-14

Publications (2)

Publication Number Publication Date
EP0002145A1 EP0002145A1 (en) 1979-05-30
EP0002145B1 true EP0002145B1 (en) 1981-07-01

Family

ID=9197570

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78400162A Expired EP0002145B1 (en) 1977-11-14 1978-11-02 Grinding machine with a narrow belt

Country Status (5)

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EP (1) EP0002145B1 (en)
DE (1) DE2860814D1 (en)
ES (1) ES475066A1 (en)
FR (1) FR2408428A1 (en)
IT (1) IT1100087B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6569002B2 (en) 1999-12-10 2003-05-27 Porter-Cable/Delta Hand-held oscillating spindle sander

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2064476A (en) * 1931-07-25 1936-12-15 Gustave T Johnson Abrading machine
FR1165605A (en) * 1955-12-13 1958-10-28 Corning Glass Works Grinding machine
US3529384A (en) * 1967-04-21 1970-09-22 Carborundum Co Sanding machine
US4038784A (en) * 1976-05-07 1977-08-02 Acrometal Products, Inc. Method and apparatus for cross grain abrading to produce a rough-sawn effect

Also Published As

Publication number Publication date
EP0002145A1 (en) 1979-05-30
FR2408428A1 (en) 1979-06-08
IT7829559A0 (en) 1978-11-08
FR2408428B1 (en) 1982-12-03
DE2860814D1 (en) 1981-10-08
IT1100087B (en) 1985-09-28
ES475066A1 (en) 1979-04-01

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