EP0796707B1 - Method and device for feeding a workpiece in a circular saw - Google Patents

Description

The subject of the present invention is a device and a process to ensure thrust, against the cutting blade a circular sawing machine, a piece to be cut, according to the preamble of claim 1. Such a device and such a method are for example known in US-A-4,603,662.

As is well known, among machine tools used in carpentry, there are sawing machines disc, more commonly known as "circular saws", essentially constituted by a frame which supports a cast iron tray through which protrudes, through a slot, the circular segment-shaped part of a disc steel with a serrated, serrated edge which constitutes the cutting blade.

The cutting operation consists, for the operator, in support the piece of wood to be cut, designated below under the term "board", on the cast iron plate, in then pushing said board against the rotating blade, this which has the effect of dividing it into two parts according to a straight cutting line.

On the plateau, parallel to the projecting part of the blade, there is also a stop which serves as lateral support for the board and, at the same time, thus defines the width of the part of said board that is to be cut.

A disadvantage that manifests itself when using a circular sawing machine for cutting a board in half pieces, is constituted by the risk of injury that the operator can suffer when the board is about to be completely cut, since the rotating blade comes then be close to the operator's hand which pushes and, at the end of the operation, when said operator must move the cut piece away from said blade.

Normally, both to push the cutting board and to move the cut part of the board away from the blade cut, the operator uses a rod with which he acts near said blade.

This system, which can be roughly compared to a manual operation is difficult, especially since the safety standards have required the use of safety placed around the cutting blade which protectors, in addition to being obviously a gene for the pushing operation of the cutting board, do not not allow the operator sufficient vision of the area of the cutting blade.

The main object of the present invention is to create a device that can replace the operation manual workpiece push or cutting board final phase of the cutting operation and which, moreover, can move the part of the board which has been cut.

The drive of the device according to the invention is fully automatic, so there is no longer the operator that the only task of pushing the cutting board up to a safe distance from the cutting area, thus avoiding any risk of possible accident for the operator and leaving to the aforementioned device the task of complete the operation.

The aforementioned device is defined in claim 1. In fact it includes a cleat which, when the end back of the board which is subject to the operation of cut crosses a predetermined limit, is placed in contact with said board and continue to push it against the rotating blade, substituting, this way, to the pushing action which, until this day, was performed manually by the operator.

The pushing action resulting from the rectilinear displacement cleat, hereinafter referred to as "push cleat", continues beyond the cutting blade, so as to move the two parts of the the board which are obtained after the cutting operation and at consequently facilitate the collection of these parts by the operator, who can operate under the conditions of maximum security.

Once the pushing action has ended, the push-stopper partially backs up, staying in waiting for a new positioning to achieve the push of the next cutting board.

The impetus for the training of the push stopper is controlled by a photocell, which detects when the back end of the work board crosses a predetermined limit, located nearby and in upstream of the rotating blade, so the operator can interrupt its manual pushing action, which is replaced by the fully automatic push action of said cleat.

Regarding construction, the push-stopper is articulated on a structure which is anchored on the platform in cast iron of the machine and which also acts as a stop lateral support for the cutting board.

Guides are provided on the machine structure used for the height adjustment of the cleat, in order to adapt it to the different thicknesses of the boards to be cut, as well as means and guides used to carry out the reciprocating linear displacement of this cleat.

Advantageously, a roller is provided on the structure crazy, placed in front of the push cleat and having the function keep the part of the work board pressed against the cast iron plate.

Finally, still in front of the push-button, also finds a safety protector which prevents rotating blade to touch said cleat in case, by mistake, the blade would protrude above the plate in cast over a distance much greater than the thickness of the cutting board.

The invention also relates to a method for the implementation of the pushing device described above.

la Fig. 1 est une coupe longitudinale du dispositif selon l'invention ;

la Fig. 2 en est une vue en plan.

la Fig. 3 illustre la phase de travail du dispositif, lorsque la planche est coupée à la suite de la poussée d'avance manuelle produite par l'opérateur, le dispositif étant encore à l'arrêt ;

la Fig. 4 montre la phase du déplacement vers l'arrière du taquet-poussoir par lequel ce dernier se place à l'extrémité de la planche partiellement coupée ;

la Fig. 5 représente la phase de poussée de la planche exécutée au moyen du taquet-poussoir ;

la Fig. 6 illustre la phase finale de la coupe de la planche.

The characteristics of the invention will be better demonstrated by the description of a possible embodiment of the device in question, given solely by way of illustrative and non-limiting example, with the aid of the appended drawing in which:

Fig. 1 is a longitudinal section of the device according to the invention;

Fig. 2 is a plan view thereof.

Fig. 3 illustrates the working phase of the device, when the board is cut following the manual advance push produced by the operator, the device being still at a standstill;

Fig. 4 shows the phase of the rearward movement of the push-stopper by which the latter is placed at the end of the partially cut board;

Fig. 5 shows the pushing phase of the board executed by means of the push-button;

Fig. 6 illustrates the final phase of cutting the board.

As we can. see it in Figs. 1 and 2, the piece of wood to be cut 1, consisting of a board, is placed on the cast iron table 2 of the circular sawing machine, above from which the circular segment 3 of the blade projects rotating 4.

The forward movement of the board 1 against the blade 4, which is used to perform the cutting operation, results from the thrust produced by a push-stopper 5, which rests on the terminal part of said board.

The cleat 5 is mounted by means of a pivot 6 on a stirrup 7 driven by an alternative translational movement.

On the stirrup 7, at a point located in front of the cleat 5, is articulated an arm 8, provided with an idler roller 9 which, thanks to a return spring 10, keeps board 1 pressed against the plate 2 during the cutting operation of this board.

A protector 21 is also fixed on the stirrup 7, in a front position relative to cleat 5, this protector being articulated on an axis 12 and having its lower end in line with the maximum projection of the circular segment 3.

A stop 14 plays the role of lateral support for the plate 1 and, at the same time, also defines the width of the part to be cut, which corresponds to the space between said stop and the protruding blade.

On the stop 14, is inserted, in the frontal position, a photoelectric cell 15 which detects the passage of the Plate 1 and, consequently, determines the location of the cleat 5, in accordance with the procedures described below.

The angular displacement of the cleat 5 and of the protector 11 on their respective axes 6 and 12, is detected by sensors 16 and 17 respectively placed near the aforementioned items.

Vertical bracket 7 is fixed in different positions to adapt the cleat 5 to the different thicknesses of the cutting boards 1, on a horizontal crosspiece 18 which is in turn supported by an underlying element 19, which rests on the cast iron plate 1 and can be positioned differently depending on the width of the part 20 that it it is a question of cutting out in plate 11.

On the element 19 is fixed a pneumatic cylinder 21 which has for the function of carrying out the rectilinear displacement alternative of the horizontal cross member 18 capable of slide on a guide 22 and, therefore, the displacement alternating rectilinear of the push stopper 5.

The cutting operation of the wooden board 1, which is shown in the different phases in Figs. 3 to 6, starts with manual operator action, which pushes said board against the spinning wool 4.

During this first phase of manual pushing of the board 1, the device remains completely stopped and, in particular, the cleat 5, by turning on its axis 6, is raise to let pass the said board below (see Fig. 3).

When following manual thrust movement, the extreme rear face 23 of the board during work crosses the photocell reading line 15, begins the action of a pneumatic cylinder 21 which drives the horizontal cross member 18 and stirrup 7, causing the backward movement, i.e. in the opposite direction advancement of the board 1, of the cleat 5 which, being able tilt on axis 6, slide on said board (see Fig. 4).

When the cleat 5, in its rectilinear displacement towards the rear, crosses the extreme rear face 23, it return to the vertical position (fig. 5).

The change of position of the stopper 5, of the orientation tilted to the vertical orientation, is detected by the sensor 16, which sends a pulse to the command which causes the cylinder stroke to be reversed pneumatic 21, with the final consequence of obtaining reversing the direction of advance of the rectilinear movement of the cleat, which therefore firstly takes support against the rear face 23 and then push the board 1 against the rotating blade 4, substituting in this way to the manual action of the operator (see Fig. 1 and 5).

At the end of the cutting operation of board 1, that is to say when the push-button 5 has passed the blade 4, the pneumatic cylinder 21 again reverses its course by bringing back said cleat back and stopping it in a position intermediate, this cleat remaining pending the next pushing operation (see Fig. 6).

Claims (13)

1. Device for thrusting the piece or board to be cut in a circular saw machine, which comprises a cast iron plate (2) through which there projects, through an appropriate slot, a circular segment (3) of a toothed rotary blade (4) which serves the purpose of cutting the piece of wood (1) which is placed on the said plate and is thrust against the said plate, characterised in that it comprises a pusher dog (5) which is driven in straight alternating motion, a photoelectric cell (15) which provides a pulse in order to put a pneumatic jack (21) into motion, the said pusher dog (5) coming into contact with the rear outer surface (23) of the said piece during work, and exerting on the latter a thrust action which permits cutting of the said piece, the said thrust action ending when, in its straight displacement, the said dog has cleared the cutting area of the blade (4).
2. Device according to claim 1, characterised in that, to the front of the pusher dog (5), it has an idle roller (9) which presses the part of the piece which is being worked, against the cast iron plate (2).
3. Device according to claim 1, characterised in that the pusher dog (5) is articulated by a pivot (12) on a clamp (7), which can be adjusted in the vertical direction in order to allow the said dog to adapt to the different thicknesses of the pieces of wood (1) to be cut.
4. Device according to claim 2, characterised in that the idle roller (9) is supported by an arm (8) which is articulated on the clamp (7) and is maintained in contact with the piece (1) by the action of a return spring (10).
5. Device according to claim 1, characterised in that it comprises a protector (11) which is articulated on the clamp (7) by a pivot (12), and has its lower end according to the axis of the projection of the circular segment (3) of the cutting blade (4).
6. Device according to claims 3, 4 and 5, characterised in that the clamp (7) is supported by a horizontal cross-piece (18), which in turn is supported by an element (19) which rests on the cast iron plate (2), the said element being able to be positioned differently according to the different widths of the part (20) to be cut from the piece (1).
7. Device according to claims 1 and 6, characterised in that the front part of the element (19) acts as a stop (14) for the lateral support of the piece (1), and thus defines the width of the part (20) to be cut.
8. Device according to claim 1 and 7, characterised in that, on the stop (14), there is inserted upstream from the cutting blade (4) a photoelectric cell (15), which detects the passage of the part (1) being cut.
9. Device according to claims 1 and 6, characterised in that the straight alternating motion of the pusher dog (5) is obtained by means of a pneumatic jack (21) which is integral with the element (19), which drives a horizontal cross-piece (18) fitted in a sliding manner on a guide (22).
10. Device according to claims 1 and 5, characterised in that the rotation of the pusher dog (5) and of the protector (11) on their respective pivots-supports (6, 12) is detected by sensors (16, 17).
11. Method for implementation of the device according to claims 1 to 10, characterised in that, when the rear outer surface (23) of the piece or board (1) to be cut crosses the reading line of the photoelectric cell (15) after the manual thrust displacement executed by the operator, the said photoelectric cell supplies a pulse to put into action the pneumatic jack (21), which, by driving respectively the cross-piece (18) and the clamp (7), gives rise to straight displacement of the pusher dog (5) in the direction which is the inverse of the direction of advance of the said piece, the said dog then being in an inclined position.
12. Method according to claim 11, characterised in that when the pusher dog (5) clears the rear end surface (23) of the piece (1) in its movement of translation, it is restored to a vertical position, and in that this new position is detected by the sensor (12), which transmits a signal of inversion of the direction of the course of the pneumatic jack (21), the said dog firstly being supported against the said surface and then giving rise to a thrust action on the said piece, in the same direction as the manual thrust action.
13. Method according to claims 11 and 12, characterised in that the displacement, combined with the thrust action of the pusher dog (5), is continued until the said dog has cleared the cutting area of the blade (4), and once this action has been completed, the pneumatic jack (21) inverts once more the direction of the course, thus bringing the dog (5) into an intermediate waiting position.

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