WO1999042267A1

WO1999042267A1 - Cutting frame for sawing blocks of stone, rock, granite, marble or the like

Info

Publication number: WO1999042267A1
Application number: PCT/EP1999/000907
Authority: WO
Inventors: Augusto Cappelli; Francesco Evangelista
Original assignee: Licia, Benassi
Priority date: 1998-02-18
Filing date: 1999-02-12
Publication date: 1999-08-26
Also published as: IT1305405B1; AU2833299A; ITSV980013A1

Abstract

A cutting machine comprises one horizontal blade-holding frame (1); one or more parallel and adjacent cutting blades (2), held by the blade-holding frame (1) for cutting one or more blocks (B); means (4, 30, 31, 201) for guiding and supporting the blade-holding frame (1), for alternatively moving it in the direction of the cutting edge of the blades (2); means (3, 103, 12, 13, 14) enabling the relative motion of the blade-holding frame (1) with respect to the block(s) (B) which are being processed, and in the penetration or downfeed direction of the blades (2) through them; means (15, 16, 17) for reciprocatingly moving the blade-holding frame (1) in the direction of the cutting edge of the blades (2). The cutting machine further comprises means (4, 104, 204, 8, 9, 10, 11) for setting the blade-holding frame (1) into a reciprocating, oscillatory and swinging movement in the downfeed direction of the cutting blades (2).

Description

Cutting frame for sawing blocks of stone, rock, granite, marble or the like

The invention relates to a cutting frame for sawing blocks of stone, rock, granite, marble, or the like, comprising: one preferably horizontal blade-holding framework; one or more parallel and adjacent cutting blades, subtended by the blade-holding framework, having the longitudinal cutting edges turned towards one or more blocks being processed; means for guiding and supporting the blade-holding framework, in such a way as to move it alternately in the two longitudinal directions of the cutting edges of the blades ; means enabling the relative motion of the blade- holding framework with respect to the block/s which are being processed, in the penetration direction of the blades through them; means for starting the reciprocating motion of the blades and of the blade-holding framework in the direction of the cutting edge of the blades .

Cutting frames of this type are known from prior art and are widely used for cutting stones, rock, marble, granite, etc. Such cutting frames may be subdivided into two groups , differing in terms of types of oscillating supports for the blade-holding framework and being used for cutting specific stone types . A first group of frames has means for guiding and supporting the blade-holding frame being arranged to set the blade-holding frame into a simply rectilinear reciprocating motion in the longitudinal direction of the blades and parallel to the blade-holding frame . The means for guiding and supporting the blade-holding frame consist of a guide and support frame which generally has a horizontal orientation, parallel to the blade-holding frame and supports said blade-holding frame by means of sliding blocks or other sliding members. A connecting rod jointed to one transverse side of the blade-holding frame, eccentrically with respect to a motor-driven flywheel, sets the blade- holding frame into a reciprocating motion parallel to itself and to the guide frame. Typically, these types of frames are used for cutting blocks of marble or stone having hard and/or poorly abrasive waste. Blades with diamond sections are used, which interact with the block over their entire length, thereby requiring a considerable driving power and involving an often insufficient waste discharge from the cutting groove. A part of the process waste is held in the cutting groove and reduces cutting efficiency, i.e. the speed of the blades through the block in the so-called downfeed direction, with a higher blade wear. Further, the rectilinear reciprocating motion damages the diamond - 3 -

setting in the diamond plate, preventing a deep embedding thereof .

In cutting frames of the second type, the blade- holding frame is supported in four locations by oscillating arms. In this case, the blades make a cut wherein the blade acts on the workpiece only by a length respectively tangent to the bottom of the cutting groove . In such rames , the blades act on the material to be cut through abrasive pulp . These frames are mainly used for cutting very hard and/or abrasive materials, such as granites, or the like. Such frames also have drawbacks reducing their performance , i.e., their cutting speed. Due to the type of oscillatory reciprocating motion the blades receive from the oscillating arms , the blades only are efficient for a fraction of the total processing time of the cutting frame. Moreover, the designed path of the cut is not fit for blades having diamond sections , which can be and in fact have been used, but reach definitely poor efficiency and life results.

Both types of cutting frames also have considerable drawbacks relating to the noise generated during cutting operations , and law constraints could only be met by providing traditional frames with a shielding to reduce noise intensity. From the above descriptions , a drawback is apparent in addition to the specific functional drawbacks of the two different types of cutting frames , in that a sawmill shall have at least two different types of cutting frames for processing the various types of stone or other . 4 .

material, specifically requiring one or the other cutting frame. This involves a considerable economic burden not only for frame purchasing costs, but also for all expenses deriving from maintenance, personnel, facilities and plants required for accommodating and operating the cutting frames .

The invention has the object to provide a cutting frame of the type described hereinbefore, whereby, with simple, easy-to-implement and relatively inexpensive arrangements, the drawbacks of prior art frames may be obviated, while improving their performance and cutting efficiency, reducing blade wear as considered with equal amounts of cut material , and considerably widening the application range as regards the types of materials to be processed, the whole with a much lower installed power, as compared with the current ones, which range from about 60 metric HP for granite cutting frames to 180 metric HP for marble cutting frames with diamond blades moving in a rectilinear reciprocating motion.

The invention achieves the above purposes by providing a cutting frame as described hereinbefore, which is provided with means for also setting the blade-holding framework in a reciprocating, oscillatory and swinging movement in the penetration direction, usually termed downfeed direction, of the cutting blades , i.e. perpendicular to their longitudinal extension, in such a way that the part of the blades in contact with the piece to be cut (cutting edge) follows any cut profile in the cutting plane and with respect - 5 -

to the workpiece itself.

According to a preferred embodiment, said means set the longitudinal ends supporting the blade-holding framework, independently from each other, into a reciprocating motion in both directions , in a direction transverse, substantially perpendicular to the longitudinal direction of the cutting edge of the blades, and with preset and/or variable widths and phases . In frames of the type with oscillating arms, this arrangement allows to control at will , within the limits of the mechanism, the impact of the blades against the bottom of the cutting groove, caused by the downfeed component, i.e. in the penetration direction, of the motion of the blade-holding frame. This allows both the use of blades with diamond sections and the attainment of efficiency advantages . Blades with diamond sections may be used by properly selecting the lowering and lifting phases for the two ends of the blade-holding framework, which provides a cut profile in which the bottom of the cutting groove has a preferably convex and/or double-pitch shape, or else, as desired, within the limits of the mechanism in use. The contact of the blades with the workpiece is theoretically limited to a point, in practice to a short section of the blade which moves along the cutting groove during the cutting stroke of the blade, and anyway does not exceed 1/2 of the blade length.

The phase differences between the reciprocating motion of the blades in the longitudinal direction and - 6 -

the reciprocating motion in the downfeed direction may be advantageously selected in such a way that the blades only contact the workpiece in one of the two reciprocating strokes, or half-strokes in the longitudinal direction of the blades, whereas in the other stroke, or half-stroke, the blade-holder is moved away from the piece, separating the blades therefrom, i.e. the cutting edge of the blades from the cutting groove . While making cuts with a convex profile, the relevant operating area of the cutting blades moves along the blades and along the bottom of the cutting groove, in the advance direction of the blade-holder, so the cutting waste is advantageously left behind the blade . In cuts in which the bottom of the cutting groove has a convex profile, the blade is lifted from said bottom for most part of its extension, and does not keep the process waste, which can freely flow from the cutting groove also thanks to the convex profile of its bottom. The effective flow of the process waste allows the use of blades having diamond sections , even in cases in which this was not conventionally allowed, such as for cutting very abrasive materials , like granite. If blades with abrasive pulp are used, the phase difference provided for the blade-holder ends in reciprocating motion transverse to the blades , with respect to each other and to the reciprocating motion in the longitudinal direction of the blades , is selected in such a way that, in the forward stroke of the blade-holder (and with reference to a convex and/or - 7 -

double-pitch cut profile) , the blades only cut the front half of the workpiece whereas, in the remaining rear half, the blades are at a distance from the bottom of the groove, the contrary being provided in the back stroke. By this arrangement cutting operations are much more efficient, the processing times and the amount of pulp required being reduced. The pulp always flows along the cutting groove in a direction opposite to the motion of the blade in said groove . Further , by increasing the number of turns of the cams with respect to the turns of the driving flywheel, a greater number of cutting phases may be obtained for each cycle (flywheel turn) . This provides a longer blade/stone contact time and hence a longer cutting time for each cycle (flywheel turn) . This is an important characteristic, given that the number of cycles in a frame is generally limited to about 90-100 cycles/minute due to the blade-holder mass. By doubling or increasing even further the turns of the cams a cutting effect equaling doubled cycles, or even more is obtained.

A further advantage consists in that, by an appropriate selection of phases, the contact of the blades with the block is always provided at one end thereof. In this manner, the portion of blade between its end and the point whereat it contacts the block is always stretched, which contributes to increase blade tension and to reduce noise .

According to an improvement of the invention, in the cutting frame, the blade-holding framework is supported by a guide and support framework in such a way as to be movable in both directions parallel thereto and in the longitudinal direction of the blades, which guide and support framework is hung to oscillating arms so as to be movable in the direction of blade penetration in the workpiece (downfeed direction) in the cutting plane, that is in the plane subtended by the longitudinal extension of the blades and by the downfeed direction thereof in the workpiece, which oscillating arms are associated to said means for setting the blade-holding framework into a reciprocating, oscillatory or swinging motion in the penetration direction, named downfeed direction, of the cutting blades , i.e. perpendicular to their longitudinal extension and are jointed to the guide and support framework, there being provided removable means for limiting and/or substantially locking any angular movement of the oscillating arms about the axis of the joint between the blade-holding framework and the guide and support framework, as well as means for limiting and/or substantially locking any relative sliding movement of the blade-holding framework parallel to the guide and support framework .

Thanks to this arrangement, the frame according to the invention may move in a reciprocating motion in the direction of the cutting stroke, as combined with the downfeed movement and with the independent swinging or oscillatory movement of the two ends of the blade- holding framework, both like a frame of the type with oscillating arms and like a frame of the rectilinear - 9 -

motion type .

The passage from one mode to the other is simple and relatively fast, being obtained by simply locking either any angular movement of the oscillating arms with respect to the guide and support framework, or any reciprocating sliding movement of the guide and support framework and of the blade-holding framework.

In an advantageous embodiment of said improvement, the oscillating arms are prevented from oscillating about the axis of the joint with the guide and support framework not by rigid means , but by elastic limiting devices , which allow limited angular staggering movements , determined in the mechanism of the guide and support framework, when its ends are moved transversely to the longitudinal extension of the cutting blades , in combination with the reciprocating motion in the longitudinal direction of the blades .

The oscillating arms are hung in such a way as to be jointed to eccentric shafts, which are in phase to each other by pairs of arms associated to each end in the longitudinal direction of the guide and support framework .

The eccentric shafts are driven so as to rotate with respect to the oscillating arms by dedicated motors or by mechanical drive systems, there being provided means for synchronizing the rotary motion of the individual eccentric shafts with each other and/or with the rotation of the flywheel of the drive shaft.

When the workpiece is not the one to be moved, the eccentric shafts are mounted on motor-driven cars , movable in the downfeed direction, and while being synchronized with each other and/or with the rotation of the drive shaft.

The invention includes further features which form the subject of the dependent claims.

The characteristics of the invention and the advantages derived therefrom will appear more clearly from the following description of an exemplary embodiment, illustrated, without limitation in the accompanying drawings, in which:

Fig. 1 is a top plan view of a frame according to the invention, with the bridge structure being shown in section .

Figs . 2 and 3 are sectional views of the frame as shown in fig . 1 , with respect to a vertical median plane, in the two extreme positions of the cutting stroke respectively, i.e with the arms of the hanger fork in a substantially locked condition, preventing any oscillation relative to the guide framework, and with the blade-holding framework being freely translatable along the guide framework.

Fig. 4 shows a magnified detail of one end of a hanger fork of the guide framework at a column of the bridge structure as shown in ig . 1. Figs . 5 and 6 are magnified lateral views of the detail of a hanger arm of the hanger fork of the guide framework in the two respective extreme positions of the stroke of the cutting blades .

Figs . 7 and 8 show, like figs . 2 and 3 , the cutting frame in the two extreme positions of the stroke of the cutting blades, with the arms of the hanger forks freely oscillating with respect to the guide framework and with the blade-holding framework being locked to the guide framework, any relative sliding motion thereof being prevented.

Figs. 9 and 10 show, like fig. 5 and 6, the magnified detail of an arm of the hanger fork in the free oscillating position thereof with respect to the guide framework as shown in figs . 7 and 8. Figs 11a to lid show four phases of the blade motion in a cutting frame as shown in figs . 2 and 3 and with the following start settings : Phase of cam 1 : 225°, speed: -VO (V0=flywheel speed), Phase of cam 2: 225° , speed: VO . Figs . 12a to 12d show four phases of the blade motion in a cutting frame as shown in figs . 2 and 3 and with the following start settings: Phase of cam 1: 0°, speed: -VO (V0=flywheel speed), Phase of cam 2: 180°, speed: VO . Figs. 13a to 13h show eight phases of the blade motion in a cutting frame as shown in figs . 2 and 3 and with the following start settings : Phase of cam 1 : 135°, speed: -2V0 (V0=flywheel speed), Phase of cam 2: 135°, speed: 2V0. Figs. 14a to 14d show four phases of the blade motion in a cutting frame as shown in figs . 7 and 8 and with the following settings: Phase of cam 1: 0°, speed: -V0 (V0=flywheel speed), Phase of cam 2: 180°, speed: V0. Referring to the figures, a cutting frame - 12 -

according to the invention comprises a quadrangular and horizontal blade-holding framework 1, subtending more cutting blades 2, which are oriented vertically, with their cutting edge turned downwards . The blades 2 are adjacent and equally spaced. The blade-holding framework 1 is supported by being hung to a guide framework 30. The latter has two sliding guides 31 for each side parallel to the blades 2 , for the engagement of a sliding block, a wheel, a roller or the like 101, carried at the upper end of extensions 201 of the corresponding longitudinal side of the blade-holding framework 1. Between the blade-holding framework 1 and the guide framework 30, there are provided removable means 33 for locking the free mutual sliding movement of said two frameworks . Said locking means 33 may be of any type and in the embodiment as shown (see fig. 4) are schematically shown as pins or pegs , interacting with coincident through holes formed in the guides 31 and in the slide member carrying extensions 201 of the blade-holding framework 1. Hence, on insertion of said pins or pegs , the two frameworks 1 , 30 may be locked to each other, the free mutual sliding movement thereof being prevented.

The guide framework 30 is supported inside a bridge frame 3 , which has four columns 103 at corner zones. The guide framework 30 is jointed at the two ends, with axes 304 transverse to the blades 2, to respective hanger forks 4, having vertical arms 104 which can be rigidly connected to each other for each end. The vertical arms 104 are jointed, by their lower - 13 -

free end to the corresponding longitudinal side of the guide framework 30. Each arm 104 is provided with means for controlling the oscillation width and locking any oscillation with respect to the plane subtended by the guide framework 30 , which may be used as elastic angular staggering-limiting devices, as provided on pages 9-10 , or as means for locking any angular movement of the hanger arms 104, when needed, and also as described on pages 9-10. With reference to the illustrated embodiment, and to their simplest and most inexpensive version, said means consist of two limiting plates 404, parallel to the facing upper surface of the corresponding longitudinal side and disposed on the two diametrically opposite sides of the joint axis 304, while said upper surface of the longitudinal side is provided with elastic abutment means 5, interacting with said limiting plates 404. Each limiting plate 404 is supported so as to be able to reach its position and be locked therein in the two directions perpendicular to the longitudinal side of the guide framework, for example by means of a support threaded pin engaged in a threaded hole of a cross member 504 , borne by the hanger arm 104 in the zone wherein it is jointed to the guide framework 30. The elastic abutment means 5 of the two plates may consist of blocks of an elastic material 105 , such as a suitable rubber or a plastic material having predetermined elastic characteristics , which are accommodated in anti-bulging container cup 205. Particularly, said blocks have a cylindrical shape and are accommodated in metal cylindrical cups . - 14 -

By properly adjusting the distance of the limiting plates from the elastic blocks 105, it is possible to limit the oscillation width of the hanger arms 104 with respect to the guide framework 30 , or even suppress said oscillation within the limits of a slight angular staggering movement given by the elastic deformability of the blocks 105.

The transverse branch 204 of the hanger fork 4, which connects the associated hanger arms 104 to one of the ends of the guide framework 30 is tubular and cylindrical, a shaft 8 being passed therethrough and being rotatably integral with at least two eccentric disks 9 fastened to the shaft at the ends of the tubular transverse branch 204. Said transverse branch 204 of the hanger fork is supported in such a way as to be able to oscillate around the disks 9 by means of annular bearings 10. One or both ends of the shaft 8 are dynamically connected to a motor reducer 11, which is designed to rotate said shaft about its axis at a predetermined speed and with a predetermined phase, as related to the speed and phase of the reciprocating motion drive motor for the blades 2 and the other shaft 8. The two ends of each shaft 8 are freely rotatably supported each in a saddle or a carriage 12 which is engaged in a guide associated to the corresponding column 103 of the bridge frame. The saddle or carriage 12 is motor-driven or associated to actuators of any YP^e _/ which in the example consist of a threaded rod and nut screw drive. The threaded rod 13 is dynamically connected to a rotary drive motor 14 , whereas the nut screw is rotatably supported by the saddle or carriage 12.

The reciprocating motion of the blades 2 in the cutting direction is obtained thanks to a connecting rod 15 which is jointed to a cross member of the blade- holding framework 1, the other end thereof being eccentrically jointed to a flywheel 16, rotatably driven by a motor 17.

The block B to be processed is disposed under the cutting frame, and may be transported by a vehicle, a car, or the like 18, for example on rails 19.

All drive motors are preferably electric motors and are synchronized as regards rotational speed and rotation phase with the main cutting motion drive motor 17 by an appropriate synchronizing unit 20. Alternatively, a mechanical or partially mechanical synchronization may be also provided.

The individual rotating parts , such as the threaded rods associated to the saddles 12 and the hanger arms 8 of the hanger forks may be controlled by a single main motor, controlling more kinematic chains for motion distribution.

The frame according to the invention as shown in figs . 1 to 6 operates as a so-called rectilinear frame . The blade-holding framework 1 may slide freely in both directions along the guides 31 of the guide framework 30, whereas the eccentric shafts 8 for jointing the two hanger forks are alternately lifted and lowered with respect to the downfeed level with a predetermined phase and at a predetermined speed with respect to the - 16 -

cutting strokes of the blades 2. The hanger arms 104 of the guide framework are substantially locked in such a way that they do not oscillate with respect to it, thanks to the limiting plates 404, which are completely lowered against the elastic members 105. The latter allow very little oscillation for compensating the momenta acting on the arms when the guide framework 30 reaches the inclined positions. This is shown, exaggerating the effects thereof for the sake of clarity, in figs. 2 and 3 and 5 and 6.

In figures 7 to 10 , the blade-holding framework 2 is locked with respect to the guide framework 30 by the pins or pegs 33 , whereas the limiting plates are lifted to a predetermined extent from the elastic abutments 5 , whereby the hanger arms 104 may oscillate freely with respect to the guide framework 30 in the range between the two predetermined extreme positions . In these conditions , the frame operates like a frame with oscillating arms, and the blade-holding framework may perform the cutting reciprocating motion thanks to the oscillation of the hanger arms 104. At the same time, the inclination of the blades in their cutting plane may be also provided by lifting and lowering the ends of the guide framework 30 and of the blade-holding framework 1 , which is obtained by rotatably driving the shafts 8 for jointing the hanger forks 4 at a predetermined speed and with a predetermined phase .

In figures 11 to 14, a few examples of cam phase and rotational speed settings are shown, as related to the rotation phase and speed of the drive flywheel . - 17 -

In figures 11a to lid, the cutting frame shown in a diagrammatic view derives from the rectilinear motion frame as shown in figs . 2 and 3. A first setting provides that the first cam 1 has a phase and speed as follows, Fl=225° and V1=-V0 , in which VO is the speed of the flywheel , and that the second cam 2 has a phase and speed as follows, F2=225° and V2=V0. Here, the blades make a cut in which the contact point between the blade and the block B follow an arched convex profile. As is evident from arrows FI , F2 and F3, the blades only interact with the block in one direction, whereas, in the oppositely directed stroke, the blades are lifted from the block. It has to be noted that in these figures , and in the following ones , the blades are never shown in direct contact with the block, in order to provide a clearer illustration of the type of cut.

Figs . 12a to 12d show the cut obtained with further phase settings, in which the phase of the first cam is F1=0° , whereas the phase of the second cam is F2=180° . The speed settings are like in the previous example. The cut obtained therefrom has a house-shaped profile. As is apparent from figures 12a to 12c, and from arrows F4 and F5 , in this example the blades operate always in the same direction of their longitudinal extension, according to each half thereof, while the directions of the half blades in the operating condition are opposed to each other. Also here, the possibility to successfully use diamond blades is given, since each half blade performs - 18 -

processing movements in the same direction and opposite to the other half.

The example of figures 13a to 13h show eight phases of a frame as shown in figures 11 and 12 , wherein the following settings have been selected: phase of the first cam Fl=135° and likewise: phase of the second cam F2=135° . As for the rotation speeds: the speed of the first cam is always contrary to that of the lywheel , the speed of the second cam is oriented in the same direction as the rotation of the flywheel, while the modulus of speed is always twice that of the flywheel . In this case , as is apparent from arrows F6 , F7 , F8 , F9, F10, Fll, the blades perform two passes for each segment, i.e. for each operating half of the blade. As a result, for each turn of the drive flywheel , the operational times of the blades are doubled. For each forward and back stroke of the frame, the blades run the cutting stroke twice. Although this operation prevents an optimized use, i.e. in one direction, of the diamond plates, cutting times reduced by half contribute to the profitability of this solution. The cut as shown has a cambered, or convex arched profile.

Figs. 14a to 14d show, like the previous figures 11 , 12 and 13 , the phases of a frame as shown in figs . 7 and 8 , with the following phase and speed settings : first cam F1=0° and speed V1=-V0 and second cam F2=180° and speed N2=N0. Here , the behavior of the blades during the cutting operation is substantially the same as that described with reference to figures 12a to 12d. - 19 -

The blades , i.e. each half blade interacts with the workpiece moving always in the same direction. The resulting cut is still of the house-shaped type. The arrows indicate the direction of the blades and the corresponding half blade operating on the block. In swinging granite cutting frames operating with abrasive pulp, this arrangement is particularly advantageous, the weight of the blade-holding panel being borne by one half frame at a time, and the waste discharge being considerably advantaged by the cut slope .

Obviously, the settings indicated herein are theoretically the best ones, but are not the only ones allowed. Besides varying the rotation speed modulus of the cams with respect to the flywheel, the phases also can be varied as compared with the above illustration and description, to fit the specific material of the blades and of the block to be sawn, and to optimize the cutting behavior according to it.

The above choices , except the one in which double speeds have been provided, cause the respective operating parts of the blade to operate always in the same direction, and hence the diamond setting to be deeply embedded in the plate. The increase of the rotation speed of the cams with respect to the rotation speed of the flywheel also increases the number of passes for each turn of the flywheel , but involves operating phases of the blades or of parts thereof in two opposite directions , which is not the optimal solution with diamond blades, unless the materials to be sawn are normally hard and/or abrasive; i.e. similar - 20 -

to those of limestone/marble.

However, in the case of a frame operating with abrasive pulp, the advantage is notable, since if with rVl I = |v2 I = rVO I , two half operating phases correspond to each stroke , i.e. one contact involving the whole blade , by varying fvi | = rV21 and having it reach |2V01 or more, anyway multiple of two, the operating phases of the frame may be increased, while keeping the number of cycles unchanged. Such number may be greatly increased, beyond 90-100 cycles/min, given the mass of the moving parts of the frame. By this arrangement, the construction of frames is greatly simplified, by avoiding the problem of the mass of the blade-holding panel which, as apparent from the theory of the rotational thrust crank mechanism, cannot be solved by balancing and is limited in its solution by the size of the dif erent members .

Naturally, the invention is not intended to be limited to the embodiments described and illustrated herein, but may be varied, especially as regards construction, without departure from the guiding principle disclosed above and claimed below. So, for example, the rectilinear guide means for the blades and the means for hanging the blades may be provided of any type . The synchronizing and driving means may be also of any type whatsoever . Moreover, the blade-holding framework 1 may be stationary, and not movable towards the block B, whereas the block is moved towards the blades . According to a further variant, the frame may also be convertible between the two modes as shown in - 21 -

figures 2 and 3 and in figures 7 and 8, i.e. from a frame derived from the rectilinear motion frame, to a frame derived from the oscillating motion frame.

A further variant consists in that, instead of moving the blade-holder , while keeping the block still, it is possible to keep the blade-holder still, while moving the block towards the blades .

The frame according to the invention also provides a wide range of construction possibilities for different types of variants. For example, there may be provided arched sliding guides 31 for the blade-holder, so that the blades follow a curved path in their forward and back strokes . The frame could simulate a blade path similar to that of the frames with oscillating arms . Here, rather than for influencing the blade path, the cams would be used for lifting the blades from the position in which they contact the block during one of the two strokes , to prevent the blades from running an operating stroke in both directions, which involves the well-known drawbacks for the diamond set in the diamond blades .

Claims

- 22 -

CLAIMS 1. A cutting frame for sawing blocks of stone, rock, granite, marble, or the like, comprising: one preferably horizontal blade-holding framework (1) ; one or more parallel and adjacent cutting blades (2) , subtended by the blade-holding framework (1) , having the longitudinal cutting edges turned towards one or more blocks (B) being processed; - means (4, 30, 31) for guiding and supporting the blade-holding framework (1) , in such a way as to move it alternately in the two longitudinal directions of the cutting edges of the blades (2) ; means (3, 130, 12, 13, 14) enabling the relative motion of the blade-holding framework (1) with respect to the block/s (B) which are being processed, in the penetration direction of the blades (2) through them; means (15, 16, 17) for starting the reciprocating motion of the blades (2) and of the blade-holding framework (1) in the direction of the cutting edge of the blades (2) ; characterized in that the cutting frame is provided with means (4, 104, 204, 8, 9, 10, 11) for also setting the blade-holding framework (1) in a reciprocating, oscillatory and swinging movement in the penetration direction, termed downfeed direction, of the cutting blades (2), i.e. perpendicular to their longitudinal extension, in such a way that the part of the blades (2) in contact with the piece to be cut (B, F) (cutting - 23 -

edge) follows any cut profile in the cutting plane and with respect to the workpiece (B, F) itself.

2. A cutting frame as claimed in claim 1 , characterized in that said means (4, 104, 204, 8, 9, 10, 11) set the longitudinal ends supporting the blade- holding framework (1) , independently from each other, into a reciprocating motion in both directions and with preset and/or variable widths and phases , in a direction transverse, substantially perpendicular to the longitudinal direction of the cutting edge of the blades (2) .

3. A frame as claimed in claims 2 or 3 , characterized in that the differences in phase, rate and direction of the oscillation or of the independent reciprocating motion of the two end zones of the blades may be selected as following a direction perpendicular thereto .

4. A frame as claimed in claim 3, characterized in that the phase differences between the reciprocating motion of the blades (2) in the longitudinal direction thereof, and the reciprocation motion in the downfeed direction of the ends of the blades (2) may be selected in such a way that the blades (2) , or at least one part thereof, only contact the workpiece (B) in one of the two reciprocating strokes in the longitudinal direction of the blade-holder (1) , whereas in the other stroke, the blades , or the part thereof which was operating in the previous stroke , is moved away from the piece .

5. A frame as claimed in one or more of the preceding claims, characterized in that the phase - 24 -

difference and the rate of the oscillation or of the reciprocating motion in the downfeed direction of the two ends of the blades (2) are selected in such a way that the profile of the bottom of the cutting groove is convex with a rounded or an inverted V profile .

6. A rame as claimed in one or more of the preceding claims, characterized in that the rate of oscillation of the blades is a multiple of the forward and back rate of the blades in the longitudinal direction thereof.

7. A frame as claimed in one or more of the preceding claims , characterized in that the phase difference provided for the blade-holder ends in reciprocating motion transverse to the blades (2) , with respect to each other and to the reciprocating motion in the longitudinal direction of the blades (2) , is selected in such a way that the blades (2) only make the cut over different halves of their length in different strokes , and always in the same direction . 8. A frame as claimed in one or more of the preceding claims, characterized in that the blade- holding framework (1) is supported at the two sides of the two opposite longitudinal ends by pairs of oscillation arms (4, 104, 204, 8, 9, 10, 304) . 9. A frame as claimed in one or more of the preceding claims, characterized in that the blade- holding framework (1) is supported by a guide and support framework (30, 31; 101, 201) in such a way as to be movable in both directions parallel thereto in the same plane and in the longitudinal direction of the - 25 -

blades (2) , which guide and support framework (30) is hung to arms (4, 104, 204, 304, 404, 504) which are oscillating (8, 9, 10, 304) and movable (103, 12, 13, 14) in the penetration direction of the blades (2) in the workpiece (downfeed direction) in the cutting plane, that is in the plane subtended by the longitudinal extension of the blades (2) and by the downfeed direction thereof in the workpiece (B) , which oscillating arms (4, 104, 204, 304, 404, 504) are associated to said means (204,

8,

9,

10, 11) for setting the blade-holding framework (1) into a reciprocating, oscillatory or swinging motion in the penetration direction, named downfeed direction, of the cutting blades (2), i.e. perpendicular to their longitudinal extension and are jointed (104, 304) to the guide and support framework (30) , there being provided removable means (404, 504; 5, 105, 205) for limiting and/or substantially locking any angular movement of the oscillating arms (104) about the axis (304) of the joint between the blade-holding framework (1) and the guide and support framework (30) , as well as means (33) for limiting and/or substantially locking any relative sliding movement of the blade-holding framework (1) parallel to the guide and support framework (30) .

11. A frame as claimed in one or more of the preceding claims, characterized in that the oscillating arms (4, 104, 204) are prevented from oscillating about the axis (304) of the joint with the guide and support framework (30) by elastic limiting devices (5, 105, - 26 -

205) , which allow limited angular staggering movements, determined when a predetermined force is exceeded.

12. A frame as claimed in one or more of the preceding claims, characterized in that the oscillating hanger arms (4, 104, 204) are hung in such a way as to be jointed to eccentric shafts (8) , the arms (104) associated to the same end in the longitudinal direction of the guide and support framework (1) being in phase to each other .

13. A frame as claimed in claim 12 , characterized in that the eccentric shafts (8) are rotatably driven with respect to the oscillating arms (4, 104, 204) by dedicated motors (11) or by mechanical drive systems, there being provided means (20) for synchronizing the rotary motion of the individual eccentric shafts (8) with the main motor (17) for starting the cutting stroke motion.

14. A frame as claimed in one or more of the preceding claims , characterized in that each pair of hanger arms (104) associated to the same end of the blade-holding framework (1) consists of end branches of a hanger fork (4) , with a transverse branch (204) for connecting the hanger arms (104) which is tubular and cylindrical, and housing at least at its ends a disk (9) wherein the hanger shaft (8) is non-rotatably mounted, the disks (9) being accommodated in the ends of the connecting cylindrical transverse branch (204) in such a way as to rotate (10) with respect to it.

15. A frame as claimed in one or more of the preceding claims, characterized in that the hanger arms - 27 -

(4, 104, 204) and/or the workpiece (B) are supported on motor-driven carriages (103, 12, 13, 14) movable in the downfeed direction and so as to be synchronized with each other .

16. A frame as claimed in one or more of the preceding claims, characterized in that the limiting devices are operating, whereas the blade-holder is free to slide in the horizontal guides, there being provided the following settings with reference to the rotation phase of the drive flywheel and to the rotation speed thereof : a phase and a speed of the first cam 1 , Fl=225┬░ and V1=-V0 , in which VO is the flywheel speed, and a rotation phase and speed of the second cam, F2=225┬░ and V2=V0.

17. A frame as claimed in one or more of the preceding claims , characterized in that the limiting devices are operating, whereas the blade-holder is free to slide in the horizontal guides , there being provided the following settings with reference to the rotation phase of the drive flywheel and to the rotation speed thereof: a phase and a speed of the first cam 1, F1=0┬░ and V1=-V0, in which V0 is the flywheel speed, and a rotation phase and speed of the second cam, F2=180┬░ and V2=V0.

18. A frame as claimed in one or more of the preceding claims, characterized in that the limiting devices are operating, whereas the blade-holder is free to slide in the horizontal guides, there being provided the following settings with reference to the rotation phase of the drive flywheel and to the rotation speed - 28 -

thereof: a phase and a speed of the first cam 1, Fl=135┬░ and V1=-V0 , in which VO is the flywheel speed, and a rotation phase and speed of the second cam, F2=135┬░ and V2=V0.

19. A frame in which the limiting devices are operating, whereas the blade-holder is free to slide in the horizontal guides, as claimed in one or more of the preceding claims, and characterized by the following settings: first cam phase Fl=135┬░ or 225┬░, second cam phase F2=135┬░ or 225┬░, whereas the rotation speeds are V1=-2V0 for the first cam and V2=2V0 for the second cam, with V0=speed of the drive flywheel speed.

20. A frame as claimed in one or more of the preceding claims, characterized in that the blade- holder is locked in the horizontal guides, whereas the limiting devices are adjusted in such a way as to allow the oscillation of the support arms , there being provided the following phase and speed settings : first cam Fl=180┬░ and speed V1=-V0 , and second cam F2=0┬░ and speed V2=V0.

21. A frame as claimed in one or more of the preceding claims, characterized in that the blade- holder is locked in the horizontal guides, whereas the limiting devices are adjusted in such a way as to allow the oscillation of the support arms, there being provided the following phase and speed settings : first cam F1=0┬░ and speed V1=-V0 , and second cam F2=180┬░ and speed V2=V0.