AU714201B2 - Improvements in milling systems - Google Patents

Description

AUSTRALIA

Awl' I 2:2 M 0 Patents Act 1990 O0riginal: Complete Spec-ificationh :.St anda r d Patent P100I011 Regulation 3,2 Improvements in Milling Systems Application number PN 8779 Th folwn sttmn is fullJ description of this invention, icung thie best method of performng known to me:- I Clyde Maxwell Robertson, being an Australian citizen of 6 Bardia Avenue SEAFORD VICTORIA AUSTRALIA 3198 do hereby declare this invention to be described in the following statement: .1 2 This invention relates to milling,and in particular cutting,apparatus and systems.

"Milling" wherever used within this specification shall refer to the techniques of altering the dimensions or profile of a workpiece thru physical interaction. Typically this involves the use of cutting or abrasive surfaces or blades though does not preclude the use of gas cutting means,lasers or other means appropriate to the material of the workpiece,or of welding tools. Commonly it is envisaged that the workpiece used with the present invention will be timber,and sometimes metal,and that the most commonly used milling techniques will comprise cutting or sawing,routing,grinding,sanding and planing.

SMost known milling apparatus wherein the milling tool is movable with respect to an immobilised workpiece,mount the milling tool on a carriage movable along a horizontal arm. The arm is generally perpendicular to the length of the workpiece and the milling device is typically a circular saw. Movement of the saw along the arm engages the saw blade with the workpiece to effect the cutting of same.

In the known devices,the arm assembly is horizontal and above a workbench or platform upon which the workpiece is placed. The length of the arm 25 and the bulk of the associated milling equipment and carriage upon which it is mounted encompasses a considerable floor area,especially if there is a long cutting or milling stroke. Furthermore,if an operation is to be performed at each end of the workpiece,it is necessary to be able to support the full length of the workpiece either side of the arm assembly, or else physically turn the workpiece end for end. This is not practical for long lengths. In a milling operation employing such milling machines a considerable area must be devoted to accommodate the footprint of each machine.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only.

As the invention incorporates components which may be rotated or oriented in three dimensions, it is useful at this stage to define some common reference points. The term "arm zero plane" has been defined as being a plane lying within 450 of true vertical and which is a plane in which the arm (to which a milling tool is attached) lies when at rest. However as it is possible to orientate many of the components of the device to be described, in three dimensions,it is perhaps more appropriate to use a coordinate system based on x,y and z axes. Therefore the first term to be defined is the "rest state" of the apparatus,or more specifically,of the arm of the device to be described. When in a rest state,the arm is substantially vertical.

The next terms to be defined are the x,y, and z axes. When the arm is in 15 a rest state,it lies along the y axis. The x axis shall be defined as being parallel to the track along which a carriage of the present invention travels. The z axis is perpendicular to the x and y axis. This will be made clearer from the ensuing description and accompanying diagrams.

The next terms define the three different planes which will be discussed.

The xz plane is a plane in which the x and z axis lie: the xy plane is a plane in which the x and y axis lie; the yz plane is a plane in which the y and z axis lie.

Further comment needs to be made regarding the position of various components when they are described with respect to one of these axes or planes. For instance,complications may arise when it is possible to vary components in three dimensions. An example is made of the case wherein the arm, which is in a rest state, is able to pivot about an axis parallel to the z axis. This would provide rotation of the arm within the xy plane ie: the linear arm remains within the xy plane. However, suppose the pivoting axis, which is perpendicular to the arm(which in a rest state lies on the y axis), is attached to another component allowing the adjustment of the arm in a different plane. Suppose an adjustment was made such that the pivot axis,which was previously parallel to the z axis, was now inclined 450 downwardly within the xz plane. Rotation of the arm about this axis now,willbe such that the arm no longer lies within the xy plane. The matter is further complicated if rotation of the arm about a third axis is also provided.

Thus, wherever the specification, and claims, refer to adjustment or rotation of a component about a certain axis, or within a certain plane it shall be assumed that any other adjustments in other axes or planes shall be in a central 0' (of deviation) position or rest state. For instance, if adjustment is provided within the xy plane (ie: rotation of the outer z axis),the rest state or 0O of deviation position will typical -ly be when the arm is in a vertical position. For rotation about the y axis (ie: within an xz plane-though it is noted that the arm will not wholly lie within the xz plane during this operation),then the 00 of deviation position is when an imaginary line drawn from the y pivot axis to the arm is parallel to the z axis. For rotation about the x axis (ie: within a yz plane) a 0* ofdeviation position is when typically an imaginary line from the x pivot axis to the arm is parallel to the z axis.

15 5z axis.

It is noted to the reader that if all posible options or possibilities were to be considered, then the matter and nature of the definitions would become even more complicated. It shall be assumed that the definitions made thus far are sufficient for indicating the spirit of the 20 invention as intended without overly complicating matters; that is envisaged that the orientation of many components may be made within three dimensions and that adjustment or rotation about a large number or a limited selection of possible axes may be provided or no choice at all.

25 25 It is also useful to define the term "substantially vertical" which wherever used within the specification,will represent 450 of true vertical,unless otherwise indicated.

It is also envisaged that some components such as the arm and track will in most embodiments of the present be linear. However, in some instances they may be curved which again imposes complications if they are to be described with respect to a certain axis or plane. To address this problem, whenever the instance arises where an arm is non linear, then it shall be treated as being a linear arm lying on an imaginary line which is an average through the actual non-linear arm(equivalent to a mathemati -cal regression line). For the instance where reference is made with respect to a non-linear track, especially with respect to a carriage on the track or a component on the carriage, the track shall be treated as being linear and aligned or parallel to a tangent to the actual track, which tangent is taken at a point on the track at the position of the carriage (or more specifically the point on the track at which a line normal to the arm when in a true rest state) is projected.

According to one aspect of the present invention there is provided milling apparatus comprising: a track; central fixed support and holding means for a workpiece; ejection means for a workpiece; S at least two carriages which may travel along said track and wherein each carriage includes: support and holding means for a workpiece; ejection means for a workpiece; S a swivel arm having thereon a travelling head assembly to which a milling tool may be attached and wherein the head assembly can travel in a path which is substantially vertical (as herein defined) and which allows the milling tool to interact with a workpiece supported by the carriage.

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According to another aspect of the present invention there is provided o milling apparatus in which the arm is repositionable so as to allow the path of the travelling head assembly to be adjusted with respect to one coo• 25 or more of an xz,yz, or xy plane,as herein defined.

According to a further aspect of the present invention there is provided milling apparatus substantially as described above wherein the track comprises a plurality of rails and wherein each rail is disposed vertically to, its neighbour.

According to another aspect of the present invention there is provided milling apparatus substantially as described above wherein there is provision to allow variation of the orientation of the milling tool with respect to the head assembly and/or workpiece.

According to a further aspect of the present invention there is provided a milling assembly comprising two or more milling assemblies substantially as described above,and in which the milling assemblies are linked to be controllable from a single station and to operate on a single workpiece.

6a Aspects of the present invention will now be described by way of example only with reference to the accompanying drawings of one possible embodiment thereof in which: Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

is a front diagrammatic view of one possible embodiment of the present invention, is a plan diagrammatic view of one possible embodiment of the present invention, is an end cross sectional view of one possible embodiment of a carriage for the present invention, is a side diagrammatic view of a possible embodiment of the arm and head assemblies of the present invention, is a front schematic view of a possible embodiment of the present invention, and is an end diagrammatic view of a possible embodiment of the arm and head assemblies of the present invention, and is a schematic view illustrating a possible embodiment of movements of the carriage, arm, head and support means, and is an isometric view of one possible embodiment of the present invention, and is an isometric view of one possible embodiment of the carriage, arm, head assembly, support means and clamp.

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35,3 With reference to the drawings and by way of example only there is provided milling apparatus, generally indicated by arrow 1, comprising: a track,generally indicated by arrow 2; central fixed support and holding means 8D, for the workpiece 9; at least two carriages 4, which may travel along said track 2, and wherein each carriage 4 includes; support and holding means 8, for a workpiece 9; a swivel arm 5, having thereon a travelling head assembly, generally indicated by arrow 6, to which a milling tool 7, (as herein defined) may be attached and wherein the head assembly 6, can travel in a path which is substantially vertical (as herein defined) and which allows the milling tool 7, to interact with a workpiece 9, supported by the carriage 4.

Further, there may be provided a milling system (generally indicated by arrow 10) such as illustrated in Figures 1 and 2,comprising two or more milling assemblies, each substantially as described above, in which the milling assemblies 1 are linked to be controllable from a single station, generally indicated by arrow 11, and adapted to operate on a single workpiece 9.

Each milling apparatus 1 comprises at least one track 2 along which a tracking device 3 may be positioned.

The track 2 which is generally horizontal, is also in most cases linear.

V However, it is also envisaged that where the milling apparatus is to be used in conjunction with non linear or complex work pieces the track 2 may deviate from the horizontal or may be curved.

The tracking device 3 which includes a carriage 4 is mounted on the track 2 An engagement system allows the carriage 4 to move (typically in a sliding motion) along the track 2 yet at the same time being resistent to 20 derailment.

There is a wide variety of carriage to track engagement systems 12 which r ~may be used, these including for instance, roller and groove mechanisms, bush and guide rail mechanisms and flange and rail mechanisms. These are e:eo 25 representative of only some possible mechanisms and it is envisaged that a combination of mechanisms may be used. Further, the coupling mechanism may be modified to allow the ready removal of the carriage 4 from the track 2, with or without the disconnection of sections of the carriage or track.For instance the track may be modified at a certain position to allow disconection of the carriage 4 or a coupling system (for instance a flange and slot or semi-circular collet with guide rail mechanism) may be provided so that the carriage 4 may be lifted from the track. Again these are several possibilities and it is envisaged that other derailing means may be provided or a combination thereof.

It is preferable that a system resistant to any derailment is used and in a preferred embodiment of the present invention the carriage 4 encloses two rails 12. Roller bearings provided on the carriage 23 /4 allow for the smooth movement of said carriage 4 along the rails 12. The track 2, in the preferred embodiment comprises two such rails 12 which are disposed vertically with respect to each other, ie: both share a vertical plane at any point there along. It is envisaged that most embodiments of the present invention will comprise such a vertical track wherein if there is a plurality of rails, they are disposed substantially vertical to,and parallel to, their neighbour. The footprint may be reduced in this manner.

It is also envisaged that other track arrangements may be used in the present invention, including multiple rails, horizontal or diagonally disposed (with respect to each other) rails or various combinations thereof.

15 The rails 12 of the preferred embodiment comprise steel rod of square ~.cross section though other configurations may be used according to the carriage to track coupling system. The track may be treated with a hardened coating to extend the life thereof. Coatings which reduce friction between the track and carriage may also be provided, as may 20bearings in contact with the track and/or carriage.

The carriage 4 provides support for the arm 5, head 6 and milling tool 7 9999 -which are mounted thereon. The arm 5 is pivotably connected with respect to the carriage 4. The arm 5 provides a path for the travelling head assembly thereon. It shall be assumed for simplicity that the path of the travelling head is parallel to the arm though other variations may exist. Further, the carriage 4 provides support for the workpiece 9 via arm 8 which is slideably mounted on the carriage 4 by According to the present invention the path along which the travelling 30 head assembly may travel must at least be positionable so that the path is substantially vertical. However in a preferred embodiment, and most other embodiments of the present invention, there is provided adjustment for the arms so that the path may be oriented in various directions.

35 A simple alternative embodiment enables variation of the arm and path about a single axis. The illustrated embodiment is one such case, and the adjustment may be catered for by providing a pivotable connection between the arm and the carriage. In the illustrated embodiment there is a shaft 13 which provides a pivot axis for rotation of the arm assembly.

9 a With reference to Figure 7, additional connections may be provided to allow variation of arm attitude and orientation about other axes. The range of adjustment may be limited; the range willbe dependant upon physical limitations opposed by the interaction of the components as well as considerations as to the effect that varying orientations will have upon the milling tool when it encounters the workpiece. Typically adjustment will be within 450 It is noted that the above means may also be adapted for mounting other components of a milling assembly, such as for instance, the milling tool7 to head assembly 6 or head assembly 6 to arm 5 etc..

In figures 1 thru 7 the arm 5 is connected to the carriage 4 by ashaftl3, the (pivotable) axis 12 thereof being substantially perpendicular to the longitudinal axis of the track (or for curved tracks, an axis tangential to the track at the point where the axis 12 may be projected thereon) at c. the point where the axis 12 if extended would intercept.

S A gearing arrangement may be provided to control rotation of the arm and in a preferred embodiment the shaftl 3 interacts with a worm gear box 14 mounted on the carriage 4.

It is envisaged that other mechanisms may also be provided to allow for the rotation and control the arm 5. It is also envisaged that more complex •cot systems may be provided to allow the orientation of the arm 5 in other planes than described and may already be apparent to the reader from the previous definitions of the geometries defined herein. It is envisaged 30 30 that most applications of the present invention will be in automated or eeao semi-automated operations where all or most controlling movements of the various components are controlled remotely and/or automatically. It is further envisaged that where such additional control over the orientation of the milling tool is required, it is normally preferable to provide 3 provision for such fine tuning at the point of connection of the milling tool 7 to the head 6(depending on the milling tool itself) though the provision of such variation of orientation may also be provided on the carriage 4 (eg: variation of the attitude of the face on which the arm _is mounted).

It is also desirable to provide some form of calibration so that various settings and inclinations are reproducable and so that particular paramet -ers may be entered. This will also have influence over the type of pivotal connection employed. For instance, it would be desirable to use components which allow separate adjustment of the orientation of the arm unit about each axis (such as depicted in Figure Thus a separate degree of deviation or inclination may be determined for each axis about which an adjustment is made. These factors may also influence embodiments in which orientation of the arm is controlled from the remote location.

The use of rotational motors such as electric motors, make the separate adjustment about each desired axis a more viable alternative to an omni- "'pivoting type connection. Also, it may be desirable that the exact position of an arm be monitored, as too the carriage at a remote controll 15 -ing station. This will require the use of sensing devices to ascertain these relative positions. The use of sensing devices to determine the degree of rotation and/or the distance of lineal movement about each V0.. single axis is desirable.Such devices are well known (eg: computerised numerical controlled servo systems) and would give much more accurate 20 results than monitoring via interface.

S e Other means to power the adjustment of the arm and associated components may also be provided eg: other than electric motors,hydraulic,pneumatic 2.or other systems. The arm 5 is essentially a track upon which the head D 6 (which is effectually a carriage) may progress. Once again the motion is typically a sliding movement Once again also, a variety of carriage to track coupling systems may be used though as most movements of the head 6 will be in a substantially vertical direction, and further, the head 6 will be subjected to much greater rigour than the main carriage 4, a coupling system for the head 6 to the arm 5 which is extremely resistant to any possible derailment should be used. The arm 5 and head 6 arrangeme -nt is most clearly seen in Figure 6. The arm 5 comprises a length of RHS(rectangular hollow section) having a track 16 of rectangular cross section extending along an internal face thereof. The head assembly 6 includes a carriage 17 which interacts with track 16. Bearings may be provided to allow for the smooth relative movement between same. Further in the preferred embodiment, the carriage 17 is kept within close proximity of the track 16 by the drive means 18 to which the carriage 17 is connected. Said drive means 18 is positioned adjacent the RHS stock internally,beneath the track 16.

11 a The drive means 18 will be discussed in more detail later. It should be envisaged that varaitions of the track assembly described herein may be made without departing from the spirit or scope of the present invention.

The milling tool 7 is generally fixed immovably to the carriage 17 of the head assembly 6. In most applications of the present invention, the milling tool 7 will comprise a circular saw. In most applications, any provision for additional orientation of the milling tool (blade etc) will be restricted to rotation about an axis substantially parallel or tangential to the arm 5 at or near the current position of the head 6 carriage 17. It may be more desirable to orientate the workpiece via the support means, and provision or modification of the support means to allow for same may be provided.

To support a workpiece for a milling operation, support arms 8/8D are provided combined with both horizontal and vertical clampA which hold the workpiece firmly in position. In a preferred embodiment, a central support 8D acts as an anchor to the workpiece, whilst the support means 8 mounted on the carriage 4, supports and holds the workpiece in close proximity to the point at which it is milled,and where support is most required. A horizontal supportl9 and vertical back support 20 is provided in the preferred embodiment, said back support 20 also positioning the workpiece 9 in the correct position for a milling operation.

a a The workpiece 9 may be kept in contact with the support means 8 by the use of a clamping mechanism. In a preferred embodiment of the present invention, a hydraulic or pneumatically operated clamping ejection S. 30 assembly is provided to each support means 8/8D. Safe guards may be built into semi or fully automated units so that the milling tool 7 may not come into contact with the workpiece until such workpiece 9 is firmly clamped.

Free floating support members 22 may be provided to support ends of a workpiece 9 being trimmed. These may slide along the track 2 in the same manner as the carriage 4 though typically have a simplified coupling arrangement allowing their ready removal or repositioning along the track 2.

_i I 12 Such additional support means 22 may be in a fixed (or adjustable) spaced relationship from the carriage rather than able to be freely positioned along the track. Further, each support means 22 may have its 5 own drive system allowing it to be automatically positioned along the track 2 in a similar manner as the carriage 4. Typically the driving means and position sensing means will be less sophisticated than for the carriage 4 as accuracy in positioning the additional support means 22 is not a major consideration. Further, the carriage 4 may be used to reposition the support means 22 by including a coupling means enabling the support means 22 to be shunted down the track in the same manner as a .9 railway locomotive and wagon. It is envisaged that a wide range of possibilities exist for the design and use of the additional support means 22.

In the various embodiments of the present invention, it is necessary to maintain moveable components, such as the carriage 4, and head 6, as well as arm 5, in the various desired positions and orientations during a 999e milling operation. In a manually operated or semi automatic (though not excluding fully automatic) embodiment of the present invention, a locking means may be provided to maintain the said components in their chosen ooos o. 9 positions. A wide variety of locking mechanisms are available(eg: cams, gripping surfaces,locking pins etc) which may all be used to effect.

The locking means may also be operable from a remote location (solenoids, 25 Shydraulic and pneumatic cylinders etc).

However it is envisaged that typically most embodiments of the present invention will be adapted to an automatic process, wherein movement of the moveable components is powered by a suitable means. Such power may be derived electrically, hydraulically,pneumatically or by other practical means,and it is possible that a combination of various powering means may be incorporated in to various embodiments. For instance in the preferred embodiments of the present invention, the moveable components are pneumatically driven whilst the milling tool 7 is powered hydraulically requiring both the connection of compressed air and also hydraulic power unit scources. Electrically operated units could equally well be used and it is possible that the head may be modified to allow the exchange of different milling tools and equipment.

13 a The head 6, in the preferred embodiment, is driven along the arm 5 via the drive means 18 which comprises a pneumatically operated piston cylinder.

A wide variety of commercially available pneumatic devices may be employed.

As the head 6 is capable of bi-directional travel, a unit capable of propelling the head6 bi-directionally is required, however a return mechanism such as a biasing means(eg: a spring, gas cartridge) or another drive unit could also be employed. The main carriage 4 may also be driven pneumatically along the track 2. Movement of the carriage 4 may be by means of a pneumatically or hydraulica 1 -lly driven units such as used for the head 6 as bi-directional travel is also 32 required. However, in a preferred embodiment, a cable extending substantially parallel to the track 2, controls movement of the carriage 4 along the track by A capstan type winch pulley driven via an electric servo motor, fixed to the carriage 4 Many other sensing systems may be employed on this or various other embodiments of the invention. The inclusion of an accurate position sensing device among other things, makes control of the apparatus from a remote or central location more practical.

It is envisaged that a wide variety of other driving and positioning mechanisms 2for the carriage 4 or head 6 may be employed. For instance, belt drive systems, chain and sprocket systems, driven wheels or gears which engage the track may Salso be employed. Alternative position sensors may also be employed including mechanisms which calculate the position of the carriage from markings on the Strack (or arm) or devices which calculate the distance of the carriage from a s datum point (eg: ultrasonic,microwave or electromagnetic distancing systems) and of which there is a wide variety available. The choice of any one system over another will be dependent upon the degree of precision required and the o• choice of the user.

rooq So 30 Control is also required over the arm 5 with respect to carriage 4. In a preferred embodiment, the positioning of the arm 5 is controlled by a worm gearbox 14 which interacts with the arm 5, pivotshaftl3. Again a position sensing means may be provided to indicate to the controller the exact orientation of the arm. The accuracy of such a system is dependent on the degree of 35 recision required and any number of rotational sensing devices may be employed as could any of the aforementioned positioning mechanisms for a carriage when modified accordingly.

a I _M 14 Control of the gearbox 14 may be from a central control area 11. The gearbox 14 may include its own processing equipment able to position the arm to a given orientation parameter supplied by the control 11 or alternatively such calculations may be performed by the central control unit which merely operation of the gearbox in response to position readings fed back to said control unit.

Similarly for operation of all other driven components, control may be delocentralized with each driven unit having its own processing equipment thereon able to independently control the unit under its charge according to a position/orientation parameter recieved from the central unit, or alternatively the processing may be centralized with each driven unit merely feeding information to a central control unit which directs a drive unit to move in direction or the other. (ie: Computerised numerical controlled servosystem).

Consequently, the present invention may be fully automated with control decisions being made either by a central human operator or a computer. Design 20and choice of the control area and unit will be dependent upon monetary considerations, intended application(eg: whether the unit will be used for mass production involving highly repetitive operations or short runs wherein parameters are constantly changing). It is also noted that where the term central is used in relation to control unit, this need not mean centrally l51ocated with respect to the milling apparatus 1,10 but rather localised in a certain area(or areas) which may be considerably remote from the apparatus 1,10.

Each milling apparatus 1 as described above may be combined as part of a larger assembly or system 10. For a typical application of the present which involves the cutting of timber for pre-cut framing, it is envisaged that two milling apparatus 1, each with a carriage,track and cutting apparatus will be combined into a single assembly Each cutting apparatus will be responsible for the trimming of a single end of a piece of timber 9. Thus both ends of a single workpiece may be trimmed simultaneously without movement of the workpiece, thus significantly improving the speed by which a length may be processed. Further to this, a plurality of workpieces may be cut together,as with a single workpiece.

It is desirable that wherever two or more milling assemblies are combined into a larger system, that they are adapted to be operable from a combined or central station.

Thus from one location, an operator can have control of both assemblies.

The controls may be modified so that both assemblies are synchronised though the ability to controleach assembly independently may be provided. As before described, the control need not be central with respect to the systems, but may even be remote therefrom. A transportable control unit which may be connected to the system by cable allows mobility of the operator about the system. A transportable control assembly will give greater mobility and flexibility to the operator.

9 Modifications may be provided wherein three or more carriages 4 (with associated milling machinery) operate on a single track.

99** Standard safety features may be built into the overall invention. In the 15 embodiment illustrated in Figures 1 and 2, the operator is located centrally within the unit which is safely remote from any milling operation. Guards around milling tools may also be provided as well as around any other areas desirable to be protected.

9. 0 29 0 Aspects of the present invention have been described by way of example only and it should be appreciated that additions and modifications may be made thereto without departing from the spirit or scope thereof as defined in the appending claims. appending claims.