GB1567557A - Cutting apparatus - Google Patents

Description

(54) CUTTING APPARATUS (71) We, CHARBONNAGES DE FRANCE, a Public Institute organised and existing under the laws of France of 9 Avenue Percier, 75008 Paris (Seine) France do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to cutting apparatus comprising a sawing or cutting arm having a chain driven by a rotating motor.

In the majority of known sawing or cutting arms the tension of the chain is adjusted and tensional play is taken up through the telescopic mounting of the arm. This mounting however has the effect of weakening the arm, so that it has to be overdimensioned.

U.S. Patent No. 1,934,562 proposed a rigid arm and proposed to effect tensioning of the chain by means of a guide pinion. In an arrangement of this kind the drive gear acts on the chain only at two diametrically opposite tangential points, which is very ineffective.

The Applicant of U.S. Patent No. 1,934,562 was therefore unable to abandon the arrangement in which the motor block is fixed rigidly to the frame of the arm.

The present invention seeks to provide cutting apparatus having a sawing or cutting arm which will withstand the heaviest stresses that the machine can endure, and which makes it possible to obtain the advantage of adjusting the tension of the chain while retaining the engagement of the chain over 1800 of the drive pulley. More precisely, the invention seeks to provide an apparatus which, for otherwise identical functional characteristics, can withstand a stress substantially equal to twice the usual stress through its section and its depth of cut.

According to the present invention there is provided a cutting apparatus comprising an endless cutting chain arranged to be driven by a drive gear fastened onto the output shaft of a drive motor, said chain being longitudinally guided on an elongate cutting or sawing arm having a curved guide end and extending away from the gear, said cutting or sawing arm being rigid and rigidly fastened to a frame, wherein the motor, its output shaft and the drive gear together form a unit mounted on the frame by way of adjusting and securing means, said adjusting and securing means extending in a direction substantially parallel to the direction of extent of said cutting or sawing arm.

Thus, the same pulley therefore serves both as drive pulley and as adjusting pulley, thereby in addition ensuring great compactness and very great strength of the whole arrangement.

In a preferred embodiment the unit is mounted for pivoting on the frame about an axis parallel to that of the gear and offset substantially perpendicularly to the direction of extent of the arm, and means for adjusting the unit by pivoting and securing it are mounted on the frame substantially diametrically opposite one another.

It is advantageous for either the frame or the unit, or both of them, to have at least two selectable utilisable positions for the pivoting axis.

In order to achieve this, the utilisable positions of the pivoting axis are provided by circular holes in the frame and in the unit, while the pivoting articulation is provided by one or more pivot pins, each pivot pin being inserted into one hole in the frame and one hole in the unit, all the holes being aligned.

An embodiment of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a plan view of cutting apparatus of the invention comprising a cutting or sawing arm; Figure 2 shows an axial longitudinal section of the apparatus on the line 11-Il of Figure 1; Figure 3 shows an axial cross-section of the apparatus on the line III--III of Figure 1; Figure 4 shows a section on the line IV-IV of Figure 2; Figure 5 shows a perspective view of a pivoting part for fastening the motor unit on the frame; and Figure 6 shows a perspective view of parts for adjusting and securing the motor unit on the frame.

A sawing or cutting apparatus of the invention is shown in Figures 1, 2, 3 and 4.

This apparatus comprises two constructional units, on the one hand a rotary motor unit 10, having a gear 12 fastened to its output shaft 11, and on the other hand a rigid arm 21 rigidly fastened to a frame 20.

The arm 21 and the frame 20 may be integrally formed or may be joined together, provided that they constitute a perfectly rigid constructional unit. The arm 21 is straight or curved, as is known per se, it being understood that it extends away from the gear 12 in the plane of the gear either diametrically of or tangentially to the gear 12, as is also known per se, that is to say in a direction D in the plane of Figure 1.

The two constructional units of the cutting apparatus are connected together in a manner explained in greater detail below. An endless cutting chain 22 having cutting teeth or points is driven by the gear 12 and is guided around the rounded end 23 of the arm 21 in known manner. It is guided by any suitable means, for example, by a guide groove 24 which extends along both sides of the arm 24 and around the end 23 thereof. In the description below it is assumed that the direction of attack of the arm is the direction marked by the arrow F towards a material 1 which has to be sawn, that is to say downwards in Figure 1.

The motor unit 10 as a whole is circular and is fixed to a ring 13. The frame 20 is also in the form of a ring and the two rings 13 and 20 are mounted conceptrically to one another, but with a clearance L as will now be explained.

The two rings 13 and 20 are joined together by adjustment and securing parts shown in detail in Figures 5 and 6 and supplemented by pins.

The ring of the frame 20 is provided with a plate 25 which is spaced from the plane of the gear 12 and which, on each side of the axis of the ring, carries points 32 for the fastening of adjustment and securing parts.

The points 32 are diametrically opposed with respect to one another. In the embodiment illustrated sixteen tapped holes 32 are provided parallel to the axis of the ring and arranged in groups of four. Two groups of four holes 32 are intended to receive a fastening part 33 and the other two groups of four holes 32 are intended to receive a pair of adjusting blocks 34, in such a manner that the two centre points of the part 33 on the one hand and of the pair of blocks 34 on the other hand are diametrically opposite and aligned perpendicularly to the direction D of the arm, that is to say parallel to the direction of attack F.

Between each two groups of four tapped holes 32 disposed on the same side of the axis thereof the plate 25 has a cutout 26.

The fastening part 33 is housed in the cutout 26 of the plate 25 which is nearest to the side of the arm 21 actually to be used for cutting and sawing and is fixed by screws at eight points 32 on each side of the cutout 26.

The two adjusting blocks 34 are fixed symmetrically on each side of the opposite cutout 26.

The ring 13 of the motor unit 10 is provided substantially opposite the cutouts 26 with two pairs of circular holes 36 whose axes are parallel to the axis of the gear. One of these holes 36, that is to say one of the two holes which are on the side for the fastening part 33, is provided with a pivot pin 37 which penetrates into a circular recess 38 in the fastening part 33. It is advantageous for this fastening part 33 to be provided on each side with two holes 38 in order to make available two possible positions for the pivot pin 37 and thereby for the pivoting axis of the ring 13 with respect to the ring 20.It is also advantageous for the ring 20 to have a second annular plate 27 at its more distant end, this second annular plate and the ring 13 being provided with holes which can be made to coincide with one another so that a hole 40 in the ring 13 and a hole 39 in the plate 27 receive a second pivot pin 37 in alignment with that already received in a hole 36 and a hole 38.

The ring 13 has a circular hole 31 formed therein in proximity to the holes 36 opposite to the hole 36 which has received the pin 37.

The tail portion, which forms a pin 42, of a stop element 41 is introduced into this hole 31. The stop element 41 acts as an adjusting stop for the two adjusting blocks 34, by way of two screws 44 which pass in alignment through a corresponding tapped hole 43 in each of these blocks 34. Lock-nuts 45 enable the stop 41 to be secured.

It is seen that the user has at his disposal three possible places for positioning the two rings which are pivotally articulated in relation to one another, and that starting from each of these positions he will be able to adjust tension by means of the stop 41 which by means of the adjustment screws 44 permits adjustment and securing in the direction D in which the arm extends away from the gear.

The clearance previously mentioned is made sufficient to utilise all the possible movement of the stop 41 when the motor unit pivots from one of its three possible positions.

The pivoting axis, which is defined by the pins 37 in the aligned holes 36 and 38, extends parallel to the axis of the gear 12 and is offset perpendicularly to the direction D of the arm.

As seen in Figure 1, the pivoting axis is in the lower part of the motor unit and the frame, but the fastening part 33 and the adjustment blocks 34 may be transposed, thus making it possible for the tension adjustment point always to be positioned where the lever arm for the application of stresses is the longest, that is to say where the stress is the lowest possible at the adjustment and securing point.

WHAT WE CLAIM IS: 1. A cutting apparatus comprising an endless cutting chain arranged to be driven by a drive gear fastened onto the output shaft of a drive motor, said chain being longitudinally guided on an elongate cutting or sawing arm having a curved guide end and extending away from the gear, said cutting or sawing ann being rigid and rigidly fastened to a frame, wherein the motor, its output shaft and the drive gear together form a unit mounted on the frame by way of adjusting and securing means, said adjusting and securing means extending in a direction substantially parallel to the direction of extent of said cutting or sawing arm.

2. Cutting apparatus as claimed in claim 1, wherein said unit is mounted for pivoting on the frame about an axis parallel to that of the gear and offset substantially perpendicularly to the direction of extent of the arm, and wherein means for adjustment by pivoting and means for securing the unit are mounted on the frame substantially diametrically opposite one another.

3. Cutting apparatus as claimed in claim 2, wherein either the frame or the unit or both the frame and the unit has or have at least two selectable utilisable positions for the pivot axis.

4. Cutting apparatus as claimed in claim 3, wherein the utilisable positions for the pivot axis are provided by circular holes in the frame and in the unit and the pivoting articulation is provided by one or more pivot pins, each pivot pin being inserted into one hole in the frame and one hole in the unit, all said holes being aligned.

5. Cutting apparatus as claimed in any preceding claim, wherein the frame and the unit carry separable articulation means and securing means and that at least some of these means are removable for transposition.

6. Cutting apparatus as claimed in any of claims 2 to 5, wherein the pivot axis is provided by two aligned pivots positioned at the two extremities of said unit.

7. Cutting apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. possible for the tension adjustment point always to be positioned where the lever arm for the application of stresses is the longest, that is to say where the stress is the lowest possible at the adjustment and securing point. WHAT WE CLAIM IS:

1. A cutting apparatus comprising an endless cutting chain arranged to be driven by a drive gear fastened onto the output shaft of a drive motor, said chain being longitudinally guided on an elongate cutting or sawing arm having a curved guide end and extending away from the gear, said cutting or sawing ann being rigid and rigidly fastened to a frame, wherein the motor, its output shaft and the drive gear together form a unit mounted on the frame by way of adjusting and securing means, said adjusting and securing means extending in a direction substantially parallel to the direction of extent of said cutting or sawing arm.

2. Cutting apparatus as claimed in claim 1, wherein said unit is mounted for pivoting on the frame about an axis parallel to that of the gear and offset substantially perpendicularly to the direction of extent of the arm, and wherein means for adjustment by pivoting and means for securing the unit are mounted on the frame substantially diametrically opposite one another.

3. Cutting apparatus as claimed in claim 2, wherein either the frame or the unit or both the frame and the unit has or have at least two selectable utilisable positions for the pivot axis.

4. Cutting apparatus as claimed in claim 3, wherein the utilisable positions for the pivot axis are provided by circular holes in the frame and in the unit and the pivoting articulation is provided by one or more pivot pins, each pivot pin being inserted into one hole in the frame and one hole in the unit, all said holes being aligned.

5. Cutting apparatus as claimed in any preceding claim, wherein the frame and the unit carry separable articulation means and securing means and that at least some of these means are removable for transposition.

6. Cutting apparatus as claimed in any of claims 2 to 5, wherein the pivot axis is provided by two aligned pivots positioned at the two extremities of said unit.

7. Cutting apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.