Introduction

This invention relates to a quarrying mill and in particular relates to a portable mill that can be

transported to a quarry, assembled on site, and then used to cut and finish varieties of stone.

Background of the Invention

Conventional quarrying methods require the use of relatively heavy equipment that is transported to the quarry to extract and transport stone in large blocks. The large blocks are then sent to a stonemason' s yard to be cut to size and finish. All these steps require large and expensive equipment operated by specialists. A problem with transporting large stone blocks from quarries is that it is extremely difficult to ascertain the quality of the stone until the cutting and finishing process commences. Thus, many blocks are sent to the stonemason's yard only to be rejected because of flaws and internal defects. This is considerable waste of stone and adds considerably to the cost of transportation from the quarry to the stonemason's yard. It is these issues that have brought about the present invention.

Summary of the Invention

According to one aspect of the present invention there is provided a portable quarrying mill comprising a demountable frame having longitudinal rails supporting an overhead gantry extending between the rails, the gantry supporting a milling head, drive means to effect

displacement of the gantry on the rails and movement of the milling head along and up and down the gantry, thus enabling movement in the X, Y and Z directions, the milling head including means to axially rotate a cutting wheel and means to pivot the rotational axis of the cutting wheel through at least 90°.

Preferably the frame is designed to be assembled on site. The drive means may be powered by electricity, hydraulic motor or mechanical drives from a diesel/petrol engine. Preferably the milling head is designed to finish, cut and buff the stone. By varying the selection of blade the quality of cut can be altered and the mill may be used on a wide variety of stones including

sandstone, granite, marble etc.

The displacement of the milling mill through the X, Y and Z directions is preferably effected by a first drive means that drives the overhead gantry longitudinally of the rails, a second drive means that drives the cutting head longitudinally of the gantry and transversely to the rails and a third drive means that raises or lowers the cutting head relative to the rails. The first and second drive means are preferably continuous elongate chains driven by sprockets preferably driven by a hydraulically driven shaft.

Description of the Drawings

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a perspective view of an assembled portable quarrying mill with a cutting head removed for clarity,

Figure 2 is a side elevational view of the mill, Figure 3 is a plan view of the mill,

Figure 4 is an end elevational view of the mill, Figure 5 is a cross sectional view through the rail, Figure 6 is a cut away side elevational view showing the combination of a rail, chain and drive sprockets,

Figures 7a and 7b are side elevations of cross rails, Figure 8a is a side elevation showing a bearing mount for a drive shaft within the cross rail,

Figure 8b is a side elevation illustrating drive to a sprocket and chain in the main rail,

Figure 8c is an end elevational view of the drive shown in Figure 8b,

Figure 9 is a side elevational view showing drive to a drive shaft in the cross rail,

Figures 10a and 10b are perspective views of halves of a nylon block to support a bearing located in the cross rail ,

Figure 11 is a side elevational view of a carriage showing a chain drive with tensioning device,

Figure 12 is an end elevational view of the carriage, Figure 13 is an enlarged side elevational view showing a drive sprocket,

Figure 14 is a side elevational view showing the drive of a cutting head assembly on gantry rails,

Figure 15 is a side elevational view of the cutting head assembly,

Figure 16 is a plan view of the cutting head

assembly,

Figure 17 is a side elevation of part of the gantry showing the vertical drive of cross rails of the gantry, Figure 18 is a plan view of that part of the gantry,

Figure 19a is a plan view of a cross beam

illustrating drive to the gantry transverse beams,

Figure 19b is a side elevational view of the assembly of 16a,

Figure 19c is an end elevational view of part of the assembly shown in 19b,

Figures 20a, 20b and 20c are side elevational views of a cutting head supported on a leg assembly,

Figures 21a, 21b and 21c are plan views illustrating the relationship between the leg assembly and a bearing ring, Figure 22 is an enlarged view showing a bearing assembly that supports the mounting leg on the bearing ring,

Figure 23 is a side elevational view of a cutting member,

Figure 24 is another cut away side elevational view of the cutting member, and

Figures 25a, 25b, 25c and perspective views of stone cutting stages.

Description of the Embodiments

The portable quarrying mill 10 illustrated in the accompanying drawings comprises demountable components to enable delivery to a specific site on a truck. The mill can then be assembled, used and then disassembled for transportation away from the site.

As shown in Figures 1-4 the mill 10 comprises a rectangular frame 11 in the form of elongate main rails 12, 13 of approximately 8m in length and supported by cross rails 17, 18 which are 6m in length. Each corner of the frame is supported by a jacking leg 15 with a turn handle 16 that allows the height to be adjustable to compensate for uneven terrain. Each rail 12, 13 supports a carriage 20 comprising a base enclosure 21 and

upstanding posts 21, 23 joined by a bridge 24 to form a U- shaped post. The upstanding arms 22, 25 in turn support a rectangular gantry 30 that comprises transverse rails 31, 32 joined by cross members 33, 34, and 36. The gantry 30 supports a cutting head assembly 50. As shown in Figure 3 the bridges 24 of the gantry are interconnected by spaced parallel bracing members 38, 39.

The carriages 20 and gantry 30 are displaceable longitudinally of the main rails 12, 13 of the frame 11. The gantry 30 is displaceable vertically relative to the posts 21, 23 and the cutting head assembly 50 is displaceable along the length of the gantry 30 on the transverse rails 31, 32. Thus the cutting head 50 can move in the X, Y and Z axes. Each carriage 20 is driven longitudinally of the rails 12, 13 by a chain and sprocket drive 40 housed within each rail. A similar chain and sprocket drive 60 drives the cutting head assembly 50 along the gantry 30. The chain and sprockets are located within the beams 31, 32 that make up the gantry 30 and the drive 35 for the sprockets is located in one cross member 34. The vertical displacement of the transverse beams 31, 32 and cutting head 50 is effected by four vertical ACME screws 46-49 located in each corner of the gantry as shown in Figures 2 and 3.

As shown in Figures 6 and 9 each chain and sprocket drive 40 of the rails 12, 13 comprises a elongate chain 41 with sprockets 42, 43 at each end. The sprocket 42, 43 are interconnected and driven by shafts 44, 45 extending along and within the cross beams 17 and 18. The beam 17 includes a hydraulic drive 47 which rotates the shaft 44 to drive the drive sprocket 42 at each end of the shaft. The other beam 18 supports an idler shaft 45 that supports sprockets 43 at the opposite end of the frame.

As shown in Figures 5 and 6 each rail 12, 13

comprises a rectangular hollow enclosure 9 with a U-shaped channel 8 fabricated on top. The chain 41 is located in the base of the channel 8 and returns along the base of the hollow enclosure 9. The rectangular enclosure 9 houses the sprockets 42, 43 at each end with the

continuous chain 41 joining the two sprockets 42, 43. As shown in Figures 7 each cross rail 17, 18

terminates in a V section 8 that locates in a

corresponding recess in the main rails 12 and 13. Each cross member includes spaced bearings assemblies 7 to support the shafts 43, 44, 45 that drive the sprockets 42, 43 in the main rails 12, 13. As shown in Figures 8 to 10 these bearing assemblies 7 comprise a Y roller bearing 151 that is mounted in a nylon block 152 that is secured within the interior of the cross rails 17, 18 by

appropriate fastening bolts 153 that are threadedly engaged in captive nuts 149 in the nylon block 152. As shown in Figures 10a and 10b the nylon block 153 comprises two square halves 146, 147 that are bolted together at each corner by fasteners (not shown) . A recess 148 along the mid point of each side holds the captive nuts (not shown) . The nylon block has a central circular aperture 154 through which the shaft 44, 45 extends supported by a Y roller bearing 151 supported by the block halves 146,

147. As shown in Figure 9 the cross beam 17 that supports the hydraulic drive 47 has two such bearing assemblies 7 mounted on either side of the shaft 44 adjacent the hydraulic drive 47 which is driven by a sprocket 155 located between the bearings. Each end of the shaft 44, 45 has a splined male end 156 that fits into a female socket 157 that is in turn coupled to the sprocket 42, 43 that drives the chain 41 in the main rails 12, 13. This arrangement is shown with particular reference to Figures 8. As shown in Figures 7 five equally spaced bearing assemblies 7 are provided in cross rail 18 which is supports the idle shaft 45 whilst the cross beam 17 that supports the hydraulic drive 47 has six bearing assemblies 7 to support the drive shaft 44.

The drive between the carriages 20 and rails 11 and 12 is shown with particular reference to Figures 11 to 13. The rectangular base enclosure 21 that supports the U- shaped posts 22 and 23 and bridge 24 is arranged to be a running fit via track wheels 55, 56, 57 and 58 that run on bearings 60 over the channel 8 that is upstanding from the rail 11. The chain 41 extends through the U-shaped channel 8 and then is turned upwardly into the rectangular enclosure 21 via a first sprocket 61, upper sprockets 62 and 63 and a return sprocket 64 which returns the chain back into the channel 8 at the top of the rail. A

tensioning device 70 tensions the chain 41 to ensure that there is interconnection within the drive sprockets that causes the carriage 20 to move longitudinally of the rail. A cross bracket 80 supports a shaft 81 that in turn supports a tensioning sprocket 82. The bracket is mounted to be displaceable in the vertical sense against coil springs 83 and 84. The bracket is slidable among vertical guides 86 and 87 and the threaded rod 88 with an adjusting nut 89 pulls the tensioning sprocket and support shaft downwards to tension the chain 41.

As shown in Figure 1, each rail 12 and 13 supports a carriage 20 driven in the manner described above via continuous chains 41. The elongate transverse gantry rails 31 and 32 support the cutting head assembly 50 that is driven along the length of the rails in a manner very similar to the drive between the main rails 12 and 13 and carriages 20.

As shown in Figures 4, 14 and 15 each transverse rail 31 and 32 supports a hollow walled carriage 90. The cutting head 50 is suspended underneath the carriages 90. As shown in Figure 11 each carriage 90 is displaceable along the transverse rails via track wheels 93, 94 and 95. A drive chain 101 extends up into the enclosure through four spaced sprockets 96, 97, 98, 99 two 97, 98 of which can have their spacing adjusted to tension the chain. In this manner, the carriage 90 on each side of the gantry rails 31, 32 moves longitudinally of those rails 31, 32 to cause transverse movement of the cutting head assembly 50 along the gantry relative to the main rails 12 and 13. As shown in Figures 17 to 19 each ACME rod 46 to 49 threadedly engages a sprocket 71, 72 and mount 73, 74. The mounts 73, 74 are connected to the transverse beams 33 or 36 and the sprockets 71, 72 are interconnected by a chain 75 so that the chain rotates the sprockets to drive the mounts 73, 74 of the beams up and down the screws 46 to 49. In this way, the cutting head assembly 50 is moved up and down vertically relative to the gantry 30. The chain 75 that drives the sprockets is driven by a

hydraulic motor 76 located centrally of the transverse beam 33. The hydraulic motor 76 has an output sprocket 77 that meshes with two idler sprockets 78, 79 mounted on the beam 33 and the chain then drives the sprockets 73, 74 secured to the ACME screws 46, 47 at either side. The motor 76 is displaceable in a horizontal sense to tension the chain 75 as necessary. The chain 75 leaves the transverse beam 33 and runs down a rail 80 on the inside of the beams 31 and 32 across the gantry so that drive from the motor 76 extends across the gantry along beams 31 and 32 and through the cross beams 33 and 36 to cause drive up and down the gantry posts 22, 23.

The cutting head assembly 50 is supported about a bearing ring 100 that is suspended from the underside of the carriages 90 by a bracket 119. Details of this assembly is shown with reference to Figures 14 to 16. The bearing ring 100 supports a fabricated leg structure 110 that in turn supports the cutting head 140. This

arrangement is shown with particular reference to Figures 17 to 19. The bearing ring supports four leg mounts 111, 112, 113, 114, that extend down from the underside of the ring 100. The mounts 111-114 are in a square array as shown in Figures 20 to 21 and are suspended from

adjustable bracket assemblies 150 that are arranged to be a running fit on the bearing ring 100. The bearing ring 100 is a rectangular cross section and the bracket

assemblies 150 comprise roller bearings 151, 152 mounted at 45° to run in the opposed apexes 102, 103 of the ring. The bearing assembly 150 is shown in particular detail with reference to Figure 23. The four leg mounts 111-114 support the cutting member 140 that is in the form of a hydraulic motor 141 that drives a cutting blade 142. The cutting member is mounted at the end of the leg mounts 111-114 to be pivotal about a horizontal axis between a vertical position shown in Figure 20a to a horizontal position (Figure 23) or even 30° past the horizontal.

The whole assembly 140 is rotatable about the bearing ring 100 through use of the bearing assemblies 150. Each leg terminates in a apertured flange 121 that forms part of the bracket 119. The flange 121 is located on an adjustable bolt 122 that carries a pair of adjusting lock nuts 123, 124 that engage on opposite sides of the flange 121 as shown in Figure 22. The bolt 122 terminates in a nylock nut 125 and coil spring 126, and the opposite end of the bolt 122 has Y shaped jaws 127, 128 that engage a pivot pin 129 and support shafts 131, 132 for the bearing assemblies 150 ride on the apexes 102, 103 of the bearing ring 100. The pivot pin 128 has a shaft 129 that extends through the adjust nut 125 and the assembly is held in engagement with the bearing shafts 131, 132 through the adjusting nut 125 and coil spring 126.

Figures 23 and 24 show specific views of the cutting head 140 with the cutting blades 142 bolted to a rotating shaft 144 that is in turn driven by a hydraulic motor 145 that is suspended by the leg structure at the base of the bearing ring 100.

A series of brakes (not shown) are incorporated on the shafts that drive the various sprockets. These brakes are of the spring loaded disc variety that lock up when not powered but can be released through movement of a manual release lever. Thus, when there is no power to the assembly the brakes are locked and thus preventing all movement. When the apparatus is to be used power is applied to the brakes to release the brakes and effect movement of the componentry. The manual override provides an ability to move the components when there is no power. The brake is a conventional proprietary type, an example of which is marketed under the trade mark INTORQ BFK458. This is a spring applied brake with a single disc with two friction surfaces and de-energized several compression springs are used to generate the braking force. The brake is released electromagnetically but, as mentioned above can also, be released manually.

Typical Operation Sequence for milling 400mm X 200mm X 200mm blocks .

1 ^st Cutting Stage (Figure 25a)

The mill 50 is set up in position and level on site. The cutting head 50 is adjusted with the blade 142 in the vertical mode and is positioned to the right hand side of the gantry.

The gantry is lowered to a depth of 200mm, it is then locked in position by a brake on the traverse beam system. A cut is commenced along to the axis of the main rail. When this cut is completed, the blade is raised out of the rock. The brake is released and a brake is applied to the main rail. The cutting head 50 is moved 400mm to the left, then lowered back to the 200mm depth and the

traverse brake applied. The brake on the main rail is released and a new cut is commenced back to the start end of the rails. On completion, the process is repeated until the series of vertical cuts are finished. When vertical cuts are finished, the traverse brake is released and cutting head 50 is returned to its original start position. 2 ^na Cutting Stage (Figure 25b)

The cutting head 50 is adjusted so the blade 142 is in a horizontal plane. The 200mm depth of cut is

maintained from the previous operation. The traverse brake is applied. The blade is then fed into the rock on the along the main rails to a depth of 200mm.

The brake is applied to the main rails and the traverse brake released. A single cut is taken along the axis of the traverse beam. When this cut is taken, the brake on the main rail is released and the blade is removed back 200mm. The cutting head is then returned to the start position .

3 ^ra Cutting Stage (Figure 25c)

The cutting head 50 is raised above any obstructions and adjusted back so the blade 142 is vertical. It is then rotated on its main thrust bearing through 90 deg.

The cutting head is then fed in on the main rails 200mm, and then the brake on the main rail is applied.

The gantry is lowered back to the original 200mm depth of cut. A cut is taken along the axis of the traverse beams. As the blade cut moves to the left of the start point it releases each block in turn. Before the block is fully released from the main body of rock, a lifting cradle is inserted into the previous horizontal cut. A lifting winch on a track trolley then carries the finished block to a loading pallet. When the entire row is completely finished the cutting head is returned to the start

position.

To continue milling blocks on the same layer, repeat steps from the 2 ^nd cutting stage. When the entire layer has been milled, the gantry is lowered to repeat the process from the 1 ^st cutting stage. This invention is especially designed for use on site. The mill is transported to the site on a truck and the power associated with the truck namely, the trucks motor, a separate generator or a hydraulic pump is

utilized to drive the mill. The mill is assembled on site and provides a framework that allows a variety of stone to be cut along three axes so that the stone is cut to size ready for the finishing steps. By cutting the stone to size on site there is no need to transport large pieces of stone to a stonemason to finish the cutting process. The cutting of the stone on site also provides an indication of whether the stone is faulty and does away with the current practice of transporting faulty stone long

distances only for the stone to be then discarded.

The mill is sturdy and effective yet dismountable to be easily transported. The drive mechanisms for the moving components of the mill are housed within steel structures and protected from damage in use. Although the preferred power is the use of hydraulic pumps it is understood that other power sources and drives are

envisaged such as electrical power to drive stepper motors . One option is to replace the chain and sprocket drives by electrically driven linear actuators which render the assembly move compact, and lighter whilst providing precise control of movement. The mill has been designed so that it does not avail itself of conventional mains electricity but relies on the variety of power sources that can emanate from a truck.

It is further understood that the cutting head 150 may also incorporate buffing, polishing and other

finishing tools to further process the cut stone on site. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.