AU7610898A - Saw system - Google Patents

Description

AUSTRALIA

Patents Act 1990 a

I

COMPLETE SPECIFICATION STAN1DARD

PATENT

Applicant(s): MOUNT SHAMROCK PTY LTD A-C-N. 005 471 456 Invention Title: SAW SYSTEM The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 SAW SYSTEM This invention relates to a saw system.

Saw systems are known and conventionally used for cutting workpieces to prescribed lengths and at prescribed angles.

Typically, such saw systems are used in the fabrication of building components including trusses and other wooden frame components.

The present invention, in a first aspect, may be said to reside in a saw system, including: a workpiece support platform for supporting a workpiece; a saw table top; a saw and saw blade supported by the saw table Stop; moving means for moving the saw table top f transverse with respect to the workpiece support platform 20 or a guide member on the workpiece support platform; rotating means for rotating the saw table top about a substantially vertical axis; and workpiece moving means for engaging a workpiece and driving the workpiece along the support platform to the saw table top for cutting by the saw blade.

Preferably the workpiece moving means comprising: a carriage supported for movement along the workpiece support platform; an abutment member coupled to the carriage for engaging the workpiece; a continuous belt coupled to the carriage; and drive means for driving the continuous belt to in turn move the carriage along the workpiece support table so that the abutment member can engage the workpiece and drive the workpiece along the support table.

do.e -310793 3 3 Preferably the workpiece moving means includes control means for controlling the speed of movement of the carriage and therefore the workpiece whereby the control means accelerates the carriage to a predetermined speed and decelerates the carriage from the predetermined speed until the carriage stops to position the workpiece at a desired position for cutting.

It has been found that the deceleration of the carriage ensures that the workpiece can be stopped at a desired position very accurately to ensure that the desired length of workpiece is cut without fear of the workpiece being pushed past a desired stop position by the speed and otherwise abrupt shut off of the moving means. Thus, by deceleration of the carriage and therefore the workpiece, the workpiece can be positioned extremely accurately to ensure that the desired and required length of workpiece is actually cut.

Preferably the saw blade is pivotally mounted relative to the saw table top so that the blade can pivot from a retracted position away -from the workpiece to a cutting position whereby the saw blade cuts through the workpiece.

Preferably the saw blade is mounted on an idler shaft which is coupled to a saw blade motor of the saw by a drive belt, the idler shaft and the saw blade being pivotally mounted relative to the saw blade motor.

A further aspect of the invention may be said to reside in a saw system, including: a workpiece support platform for supporting a workpiece; a saw and saw blade arranged within the support platform for cutting a workpiece; workpiece moving means for moving a workpiece along the workpiece support platform to a desired position 13/07138 4 for cutting by the saw blade; and control means for controlling the workpiece moving means so that the workpiece moving means is accelerated from a stationary position to a drive speed and then decelerated from the drive speed to a stopped position to accurately locate the workpiece for cutting of a required length of workpiece by the saw blade.

As previously explained, the deceleration of the workpiece ensures that the workpiece is located very accurately at a required position so that the correct length of workpiece can be cut. The deceleration prevents abrupt stopping of the workpiece moving means which, whilst can be stopped at an accurate position by rapid removal of drive from the 15 workpiece moving means, will nevertheless result in the workpiece moving forward a further distance in view of the momentum of the workpiece which has been imparted by the drive means. The more gradual deceleration of the drive means results in gradual decrease of the momentum of the 20 workpiece so that the momentum of the workpiece does not carry the workpiece beyond a required stopped position which would otherwise result in the workpiece moving too far and therefore not being cut at the required position to provide a workpiece of the desired length.

Preferably the workpiece support platform includes a saw table top which supports the saw and saw blade.

Preferably the saw blade is pivotally coupled to the saw table top for pivotal movement from a retracted position to a cutting position for cutting the workpiece.

Preferably the saw system includes a moving means for moving the saw table top transverse with respect to the workpiece support platform or a guide member on the workpiece support platform.

H \K.ren\ K-MCUN r-sWiOCK-sK Mdoc 13107198 5 Preferably, rotating means is provided for rotating the saw table top about a substantially vertical axis.

A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is plan view of a saw system according to the preferred embodiment of the invention; Figure 2 is a front view of the saw system of Figure 1; Figure 3 is a cross-sectional view along the line III-III of Figure 1; Figure 4 is a cross-sectional view along the line IV-IV of Figure 3; 15 Figure 5 is a cross-sectional view along the line V-V of Figure 2; .Figure 6 is a side elevation of part of Figure 2; Figure 6A is a side elevation of the same part as shown in Figure 6, but from the opposite side; Figure 7 is a view of part of the arrangement shown in Figure 6 from the dire tion of the arrow marked 7 in Figure 6; Figure 8 is a schematic diagram illustrating computer control of the saw system of Figures 1 to 7; Figure 9 is a graph illustrating part of the operation of the saw system; Figure 10, Figure 11 and Figure 12 are diagrams illustrating operation of the saw system of Figures 1 to 7.

With reference to Figures 1 and 2 a saw system 10 is shown which comprises a workpiece support platform 12 which has portions 12a and 12b which are separated by a saw table top 14 which is generally circular in configuration as can be best seen in Figure 1. The table 14 has a generally central slot 16 through which a saw blade 18 can project for cutting a workpiece W to a desired length or to a desired length and angle as will be described in more 131 ~7I 6 detail hereinafter.

An abutment member 24 is mounted for movement along the portion 12a of the platform 12 to move the workpiece W in the direction of arrow A in Figure 1 to locate the workpiece at a desired position for cutting by the saw blade 18.

The platform 12 includes a rear guide wall 25 against which the workpiece W can also abut to position the workpiece W at a required datum defined by the wall 25 relative to the saw blade 18.

The table top 14, as will be explained in detail hereinafter, is movable transverse with respect to the platform 12 and wall 25 in the direction of double headed arrow B in Figure 1 and also rotatable around a substantially vertical axis as shown by double headed arrow C in Figure 1.

The table 14 may therefore be rotated in the direction of double-headed arrow C so as to angle the blade 18 with respect to the workpiece W for cutting the workpiece W at a required angle or indeed to position the blade 18 parallel to the workpiece W for cutting the workpiece longitudinally.

The table 18 can also be moved in the direction of double headed arrow B so as to position the blade 18 when the blade is arranged parallel to the workpiece W a desired distance from the wall 25 for cutting the workpiece W to provide a desired thickness of workpiece W.

Although in the preferred embodiment of the invention, the table top 14 is moved in the direction of double headed arrow B to position the saw blade relative to the wall it would be possible to move the wall 25 relative to the iJ/olii -7 support platform 12 to position the workpiece W relative to the blade 18.

As best shown in Fi.gure 2, the support table 14 is mounted on a frame 26 which includes a circular bottom frame plate 28 supported on a bearing The table 14 and the support frame, made up of the frame members 26, 28 and cross frame member 32 are carried by a support carriage 40 which has frame members 42 which in turn carry wheels 44. The wheels 44 engage rails 46 (shown in Figure 6) so that the support carriage 40 and therefore the table 14 can be moved along the rails 18 to provide the movement in the direction of double headed arrow B previously described. The carriage 40 includes a bottom support plate 43 which mounts the bearing As is best shown in Figure 6, the frame member 43 also mounts a pedestal 50 which has an upper table 52 upon which is mounted a computer 54 for controlling operation of the saw system 10. A DC servo motor 56 is arranged on frame 43 and has an output sprocket 58 which drives a belt 60. The belt 60 also engages a drive sprocket 62 on a screwthreaded shaft 64. The shaft 64 is mounted in bearings 66 and engages a screw-threaded block 68 which is fixed to the rails 46. When the motor 56 is driven under the control of the computer 54, the belt 60 rotates to rotate the shaft 64 so that the shaft 64 engages the screw-threaded block 68 which is fixed on the rails 46 so that the carriage 40 is moved back and forward in the direction of double headed arrow B as previously described and as shown in Figure 6 relative to the block 68 and therefore the rails 46. As previously explained,.this positions the table top 1 in the direction of double headed arrow B3 relative to the wor-kpiece W for splitting or cutting the workpiece

W

longitudinally to a required thickness.

U

8 The pedestal 50 supports a hydraulic ram 70 which has a ram arm 72 coupled to a guard arm 74. The arm 72 is arranged within a sleeve 74 and the arm 74 has a block 76 which can slide on the sleeve 74. The sleeve 74 is supported by plates 78. Thus, when the arm 72 is extended or retracted by the cylinder 70, the guard arm 74 can be moved upwardly and downwardly in the direction of double headed arrow D shown in Figure 6.

The guard arm 74 is pivotally coupled to a guard 80 by a pivotal coupling 82. The guard 80 has a rod 84 arranged at one side which is received within a sleeve 86 coupled to the saw support table 14.

Thus, when the support table 14 is rotated about bearing in the direction of double headed arrow C shown in Figure 1, the guard 80 rotates with the table 14 by virtue of the pivotal coupling 82 whilst the guard arm 74 remains stationary relative to that pivotal movement of the saw table 14.

Figure 6A shows the mechanism for rotating the support table 14 about the substantially vertical axis. Figure 6A is a side elevation similar to Figure 6 but from the opposite side which shows more of the detail of this mechanism. A DC servo motor 90 is mounted on frame 43 and drives a sprocket 93 through a gearbox 91. A belt 97 is engaged with the sprocket 93 and extends about the periphery of the circular frame plate 28 which is mounted on the bearing 30 and on which the saw table top 14 is arranged. The belt 97 may be clamped to the periphery of the plate 28 by a clamp 99. Tension rollers 83 are located for tensioning the belt 97 about the periphery of the circular plate 28 and may be supported by struts or plates 81. Thus, when the DC servo motor 90 is driven, drive is transmitted to the belt 97 to rotate the circular plate 28 on the bearing 30 and therefore rotate the table 14.

9- When a workpiece W has been correctly positioned on the table 14, the workpiece W is clamped in place by operation of the cylinder 70 to lower the guard 80 onto the workpiece W so that the guard 80 clamps the workpiece W onto the table 14 for cutting by the blade 18.

The saw blade 18 is mounted for '3ivotal movement in the direction of arrow F shown in Figure 6 so that a saw blade can move from the position shown in Figure 6, up through slot 16 to make a cut in the workpiece W positioned on the table 14 and clamped in place by the guard 80. The saw blade 18 is powered by a motor 92 which has an output sprocket 94 which drives a belt 134. The belt 134 drives an idler shaft 98 via a sprocket 100 as will be described in more detail hereinafter. A ram 100 is mounted on frame 28 and has an arm 102 connected to one of a pair of connecting rods 104 so that when the cylinder 100 is activated, the saw blade 18 is pivoted around the axis 106 of the motor 92 from the position shown in Figure 18 up to the cutting position through slot 16 to cut the workpiece

W.

Figure 7 shows the detail of the pivotal coupling of the sawr blade 18 for movement about the axis 106 of the motor 92.

The motor 94 has a motor shaft 110 which passes through connecting rods 104. The connecting rods 104 each support bearings 112 which are mounted on the shaft 110 so that the shaft 110 can rotate within the bearings 112. The output sprocket 94 is mounted on one end of the shaft 110.and engages the belt 134 which is also engaged with a sprocket 122 on idler shaft 98 to which saw blade 18 is fixed. The shaft 98 is mounted within a sleeve 118 by bearings 123.

Thus, drive transmitted from the motor 94 via the shaft 110 to the belt 134 is applied to rotate the shaft 98 about its "Al axis to in turn rotate and drive the saw blade 18. The connecting rods 114 are coupled to connecting studs 114 by bolts 116. The studs 114 are welded onto the sleeve 118 and, as previously mentioned, the arm 102 of the cylinder 100 is connected to one of the rods 104 as shown in Figure 7. When the cylinder 100 is extended, the arm 102 pushes upwardly in Figure 6 and generally out of the plane of the paper in Figure 7 so that the pair of rods 104, together with the sleeve 118 and therefore the shaft 98 and saw blade 18 are also pivoted upwardly so that the saw blade 18 moves through slot 16 to cut the workpiece W. After cutting the cylinder 100 is retracted to return the saw blade 18 to the position shown in Figure 6 where the sleeve 118 can rest on sleeve support 144 shown in Figure 6.

The abutment 24 for moving the workpiece W on the platform 12 will be described in more detail with reference to Figures 3, 4 and 5. The platform 12 is formed from a pair of box section beams 150 which are supported by frame legs 162. A carriage 164 is mounted between the frame sections 160 and is guided on a pair of rails 166 respectively coupled to each of the frame sections 160. The carriage 164 has'recesses 168 for accommodating the rails 166. The carriage 166 is welded or otherw,.ise coupled to the abutment 24.

A shaft 170 is journalled in bearings 172 connected to beams 160 and supports a sprocket 174. A toothed belt 180 is arranged on the sprocket 174 and, as is best shown in Figure 3, extends to a shaft and sprocket 189, which is identical to that shown in Figure 4. The belt 180 is clamped by bolts 167 or the like to the carriage 164 by a clamp plate 182.

As is best shown in Figure 3, the belt 180 is guided about a guide sprocket 184, drive spro cket 186 and a further guide sprocket 188 which are mounted between plates 190 as will be described hereinafter.

Limit switches 194 and 196 are provided along the path of the belt 180 for contact by the carriage 164 so as to output pulses which can be used as position references for positioning the carriage 164 and therefore the abutment 24 so that the computer 54 can ascertain the location of the carriage and workpiece for the start of each operation.

As is best shown in Figure 5, the plates 190 which are connected to the frame sections 160 support shafts 201 and 203 in bearings 202 and 205. Drive sprocket 186 is mounted on shaft 201 and idler sprocket 184 is mounted on shaft 203. A further idler sprocket (not shown in Figure 5) is directly behind the sprocket 184 and mounted on the shaft similar to the shaft 203.

DC servo motor 292 is connected to one of the plates 190 and has an output shaft 294 which carries the sprocket 296.

A sprocket 293 is mounted on one end of the shaft 201 and an endless belt 293 extends about the sprockets 296 and 293. Thus, when the motor 292 is activated, drive is transmitted to shaft 294 and therefore to sprocket 296 which in turn drives the belt 298 and sprocket 293 to rotate the shaft 201 and drive the drive sprocket 186 to circulate the belt 180 and move the carriage 164. Movement of the carriage 164, of course, moves the abutment 24 to drive the workpiece W.

Figure B shows schematically control system where the computer 54 controls the servo motors 56, 292 and 90 for moving the saw table 14 back and forth in the direction of double headed arrow V, shifting the abutment member 24 in the direction of arrow A and rotating the table 14 in the direction-of double headed arrow C shown in Figure 1. The computer receives input information concerning the job to be performed and this may include data keyed into the H ~13/07/98 -12 computer 54 on a keyboard (not shown) or information downloaded from a job description or job lot so that length and angle of the workpiece W to be cut can be determined.

As previously mentioned, the computer obtains initial positioning information by the carriage 24 abutting stops 194 and 196 to initialise itself. Output signals are then supplied by the computer 54 to the motor 292 so that the motor 292 can be operated to circulate belt 180 so that carriage 164 and abutment 24 are moved. The computer 54 controls the speed of operation of the servo motor 292 as shown in Figure 9 by firstly determine the amount of movement of the abutment 24 which is required to cut the workpiece W to the prescribed length. The computer will then determine a first time period from to to tl at which the carriage 164 and abutment 24 are accelerated up to speed V a period from tl to t 2 at which generally constant speed V is maintained and a period t 2 to t 3 at which the carriage 164 and abutment 24 is decelerated from speed V to zero speed to stop the workpiece W at exactly the right place for cutting to the required length. As previously explained, the deceleration in the period t 2 to t 3 ensures that momentum is gradually removed from the workpiece W so that the workpiece W does not overshoot the desired stopping position which would otherwise be the case if the speed of the carriage 164 and abutment 24 was shut off abruptly. This would result in the workpiece W having moved too far and therefore being cut to an incorrect length. Thus, deceleration of the workpiece ensures accurate positioning of the workpiece for cutting the required length.

Depending on the length of the workpiece and the amount of movement required, the time period ti to t 2 may be very small and, indeed, may be zero so that the abutment 24 is accelerated from time to to tl and then immediately decelerated down to zero speed to ensure stopping at the required distance.

S.faren p lH ia -5HA i OCK-saw-ystem.d oc 3/07/1 2 13 As is shown in Figure 10, saw blade 18 results in a certain thickness of material marked d 2 being removed f rom. the workpiece W during the cutting operation as the workpiece is cut. The amount of material which is moved by the cutting operation will be known for a saw blade and, in most embodiments, will be in the order of approximately 4 mm. Thus, if it is desired to cut a workpiece W to a length d as shown in Figure 10, the end of the workpiece adjacent the abutment 24 should be a distance d d 2 from the right hand edge of the saw blade in Figure 10. Thus, if it is again required to cut another piece of material of length d, the abutment 24 should be moved a distance d d to result in the required length d being out.

if the servo motor 90 is operated to angle the blade 18 so as to cut an angle as shown in Figure 11, the amount of additional material cut by the saw blade will increase because of the angle at which the saw blade 18 makes with the longitudinal axis of the workpiece

W.

As is shown in Figure 12, the angle at which the blade 18 has been angled is 0 which will be known from the information input into the computer 54, the distance d 3 can easily be calculated by simple trigonometry so as to ensure that when cutting that angle, the workpiece is moved a distance d, d 3 to compensate for the material which will be cut from the workpiece during the cutting operation by the saw blade 18.

Thus, the computer controller 54 automatically calculates the-length of material and angles required from the information downloaded or inputted and positions the workpiece W and moves the position W the required distances 3S to make the cuts to ensure that the produced workpieces are of the required length and that cuts are made at the required angles for the job description.

st- d.c 13/07/98 V 14 Since modifications within the spirit and scope of the invention may reaaily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiments described by way of example hereinabove.

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Claims (9)

1. A saw system, including: a workpiece support platform for supporting a workpiece; a saw table top; a saw and saw blade supported by the saw table top; moving means for moving the saw table top transverse with respect to the workpiece support platform or a guide member on the workpiece support platform; rotating means for rotating the saw table top about a substantially vertical axis; and workpiece moving means for engaging a workpiece and driving the workpiece along the support platform to the saw table top for cutting by the saw blade.

2. The saw system of claim 1, wherein the workpiece moving means comprising: a carriage supported for movement along the workpiece support platform; an abutment member coupled to the carriage for engaging the workpiece; a continuous belt coupled to the carriage; and drive means for driving the continuous belt to in turn move the carriage along the workpiece support table so that the abutment member can engage the workpiece and drive the workpiece along the support table.

3. The saw system of claim i, wherein the workpiece moving means includes control means for controlling the speed of movement of the carriage and therefore the workpiece whereby the control means accelerates the carriage to a predetermined speed and decelerates the carriage from the predetermined speed until the carriage stops to position the workpiece at a desired position for cutting. XK'- !K^XaOK-.r -IY. 1L3/01/93 16

4. The saw system of claim 1, wherein the saw blade is pivotally mounted relative to the saw table top so that the blade can pivot from a retracted position away from the workpiece to a cutting position whereby the saw blade cuts through the workpiece.

The saw system of claim 1, wherein the saw blade is mounted on an idler shaft which is coupled to a saw blade motor of the saw by a drive belt, the idler shaft and the saw blade being pivotally mounted relative to the saw blade motor.

6. A saw system, including: 15 a workpiece support platform for supporting a workpiece; a saw and saw blade arranged within the support platform for cutting a workpiece; workpiece moving means for moving a workpiece along the workpiece support platform to a desired position for cutting by the saw blade; and control means for controlling the workpiece moving means so that the workpiece moving means is accelerated from a stationary position to a drive speed and 25 then decelerated from the drive speed to a stopped position to accurately locate the workpiece for cutting of a required length of workpiece by the saw blade.

7. The saw system of claim 6, wherein the workpiece support platform includes a saw table top which supports the saw and saw blade.

8. The saw system of claim 6, wherein the saw blade is pivotally coupled to the saw table top for pivotal movement from a retracted position to a cutting position for cutting the workpiece. 13107198 .1 IV qr q -R P a '~l"rF -~---rrr-rar~u~-o 17

9. The saw system of claim 6, wherein the saw system includes a moving means for moving the saw table top transverse with respect to the workpiece support platform or a guide member on the workpiece support platform. The saw system of claim 6, wherein rotating means is provided for rotating the saw table top about a substantially vertical axis. Dated this 13th day of July 1998 MOUNT SHAMROCK PTY LTD By their Patent Attorneys: GRIFFITH HACK Fellows Institute of Patent Attorneys of Australia. H.\~Een~eep~(CI1I~Si~iMX-lv-Fo~n13/D198