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Title:
TRANSPORT DEVICES
Document Type and Number:
WIPO Patent Application WO/1999/042246
Kind Code:
A1
Abstract:
A transport device comprises a track (3) and a carriage (2) adapted to engage with said track, the track having at least one drive rail having means which extend along its length and which is adapted to be engaged by a drive wheel so that the carriage may be moved along the track. The rail may be provided with a series of holes or apertures along its length and the drive wheel is provided with a plurality of radial projections for engagement with said holes or apertures to provide the drive. Alternatively a toothed rack is provided along its length and the carriage is provided with at least one drive wheel which has a pinion or toothed wheel adapted to engage the rack to provide the drive.

Inventors:
BURGOYNE MYLES COWBURN (GB)
Application Number:
PCT/GB1999/000542
Publication Date:
August 26, 1999
Filing Date:
February 22, 1999
Export Citation:
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Assignee:
QUICKSILVER PROFILING EQUIPMEN (GB)
BURGOYNE MYLES COWBURN (GB)
International Classes:
B23K7/10; B23Q5/38; B23Q9/00; (IPC1-7): B23Q5/38; B23Q9/00
Domestic Patent References:
WO1989008002A11989-09-08
Foreign References:
FR2451517A11980-10-10
FR1525343A1968-05-17
US2079864A1937-05-11
US5070792A1991-12-10
DE2219181B11973-08-30
EP0594091A11994-04-27
US3722497A1973-03-27
Other References:
PATENT ABSTRACTS OF JAPAN vol. 7, no. 54 (P - 180)<1199> 4 March 1983 (1983-03-04)
Attorney, Agent or Firm:
Burgoyne, Myles Cowburn (19 Chatsworth Grove Harrogate North Yorkshire HG1 2AS, GB)
Burgoyne, Myles Cowburn (19 Chatsworth Grove Harrogate North Yorkshire HG1 2AS, GB)
Download PDF:
Claims:
CLAIMS:
1. A transport device comprising a track and a carriage adapted to engage with said track, said track having at least one drive rail having means which extend along me length of said drive rail and which is adapted to be engaged by a drive wheel on said carriage so as to provide drive between said drive wheel and said drive rail whereby said carriage may be moved along said track.
2. A transport device according to Claim 1, wherein said track has a hollow profile within which at least part of the carriage is retained to inhibit disengagement of the carriage from said track.
3. A transport device according to Claim 2, wherein said hollow profile is at least partly defined by a pair of rails which are engaged by wheels provided on said carriage.
4. A transport device according to Claim 3, wherein one of said rails that at least partly defines said hollow profile is said drive rail.
5. A transport device according to any of Claims 1 to 4, wherein said track has at least one drive rail which is provided with a series of holes or apertures along the length of said drive rail, the carriage being provided with a drive wheel which has a plurality of radial projections adapted to engage said holes or apertures to provide drive between said drive wheel and said drive rail.
6. A transport device according to Claim 5, wherein said drive wheel may selectively engage the top of the drive rail with the carriage mounted above said track.
7. A transport device according to Claim 5, wherein said drive wheel may selectively engage said drive rail from within said hollow profile with the carriage retained at least partially within said profile.
8. A transport device according to Claim 5, wherein said projections decrease in size radially of the drive wheel.
9. A transport device according to Claim 8, wherein said projections are chamfered, hemispherical or at least partspherical to assist location of the projections in the holes or apertures in said drive rail.
10. A transport device according to any of Claims 5 to 8, wherein said holes or apertures in said drive rail are in a single row or in a plurality of adjacent rows.
11. A transport device according to any of Claims 5 to 10, wherein said holes or apertures are of oval or elliptical shape with their maximum diameter transverse of said drive rail.
12. A transport device according to any of the preceding Claims, wherein said carriage is provided with at least one additional wheel of larger diameter than the drive wheel such that the carriage may also travel over a surface of said track by traction provided by the or each said additional wheel.
13. A transport device according to Claim 1, wherein said carriage is provided with two said drive wheels and said track is provided with two said drive rails for engagement each by a respective one of said drive wheels in order to move the carriage relative to and along the track.
14. A transport device according to Claim 1, wherein said track has at least one drive rail which is provided with a toothed rack along the length of said rail, said carriage being provided with at least one drive wheel which has a pinion or toothed wheel adapted to engage said toothed rack to provide drive between said drive rail and said drive wheel.
15. A transport device according to Claim 14, wherein said toothed rack is secured to said drive rail and is located inside the hollow profile of said track.
16. A transport device according to any of the preceding Claims, wherein said track is formed of extruded metal or alloy and is provided with at least one keyway to receive fasteners for fastening the track to a support surface.
17. A transport device according to Claim 16, wherein said track has three outer faces successively at right angles to one another, each of said faces being formed with a keyway, said faces being on a base and two longitudinal side faces of said track.
18. A machine tool mounted on a carriage of a transport device according to any of Claims 1 to 17 for movement on the carriage relative to a workpiece which is fixed with respect to said track.
19. A machine tool according to Claim 18, wherein said machine tool is a cutting, profiling, or surface treatment tool or any other tool for performing an operation on metal, wood, or any other workpiece or material.
20. A machine tool according to Claim 19, wherein said machine tool is a metal cutting torch.
21. A method of carrying out an operation on a workpiece by means of a machine tool according to any of Claims 18 to 20 comprising the steps of securing the workpiece and a track of a transport device of the machine tool in fixed relationship to one another and operating the said transport device to cause relative movement between the carriage and the workpiece as the operation is carried out on the workpiece.
Description:
TRANSPORT DEVICES This invention relates to transport devices and is particularly, although not exclusively, concerned with transport devices for machine tools.

Portable flame cutting machines have been known for very many years. They are useful in situations where it is required to cut sheet metal on site. To cut a straight line by hand on site is a very difficult and skilled exercise, and obviously, on site, one does not have readily to hand large flame cutting machines or the like. Therefore, portable flame cutting machines have been developed.

One type of known portable flame cutting machine uses a track on which a carriage moves. The carriage is supported on drive wheels which engage the track and provide traction by means of friction between the drive wheels and the track. A cutting torch is mounted on the carriage, and as the carriage moves along the track, the cutting torch performs a cutting operation on a workpiece on which or

or adjacent to which the track is mounted, and since the carriage follows the track, it can cut a straight line with precision. Other items of optional equipment allow circles and other shapes or profiles to be cut.

A drawback with this type of machine is that the drive of the carriage relies entirely upon friction. Thus, if the track is at an incline, there may be insufficient traction for the carriage to be driven reliably.

Also, the weight of the cutting torch, which must necessarily be spaced to one side of the carriage, applies a lever arm effect which tends to lift the carriage from the track. If the cutting torch is very heavy, or if it is disposed at anything more than a modest distance from the carriage, there is an appreciable danger of the carriage tipping over and leaving the track, and bearing in mind that the cutting torch is operating at an extremely high temperature, this can be very dangerous.

The present invention therefore seeks to provide an improved form of

transport device which will obviate the above and other disadvantages of known transport devices.

According to one aspect of the present invention, there is provided a transport device comprising a track and a carriage adapted to engage with said track, said track having at least one drive rail having means which extend along the length of said drive rail and which is adapted to be engaged by a drive wheel on said carriage so as to provide drive between said drive wheel and said drive rail whereby said carriage may be moved relative to said track.

Preferably, said track will have a hollow profile within which at least part of the carriage is retained to inhibit disengagement of the carriage from the track, and the hollow profile will preferably be at least partially defined by a pair of rails which are engaged by wheels provided on said carriage.

One of said rails that at least partially defines the hollow profile will

preferably be said drive rail.

In a first embodiment of the invention, the track will have at least one drive rail which is provided with a series of holes or apertures along the length of said drive rail, and the carriage will be provided with a drive wheel which has a plurality of radial projections adapted to engage said holes or apertures to provide drive between the drive wheel and the drive rail.

Preferably, the arrangement is such that the drive wheel may selectively engage the top of the drive rail with the carriage mounted above the track, or engage the drive rail from within the hollow profile, with the carriage retained at least partially within said hollow profile.

Said projections will preferably decrease in size radially of the drive wheel, and to this end they may be chamfered, hemispherical or at least part-spherical which may assist location of the projections in the

holes or apertures in the drive rail.

Said holes or apertures in said drive rail may be in a single row or in a plurality of adjacent rows. In the latter case, the holes or apertures of adjacent rows may be staggered.

Said holes or apertures may be of oval or elliptical shape with their maximum diameter transverse of the drive rail.

Preferably, said carriage will be provided with at least one additional wheel of larger diameter than the drive wheel such that the carriage may also travel over a surface of said track by traction provided by the or each said additional wheel.

The carriage will preferably be provided with two said drive wheels and the track will preferably be provided with two said drive rails for engagement each by a respective one of the said drive wheels in order to move the carriage relative to and along the track.

Preferably, said track will be formed of extruded metal, and for example of aluminium, and the track will preferably be formed with at least one keyway to receive fasteners for fastening the track to a support surface.

Preferably, said track will have three outer faces successively at right angles to one another, each of which faces is formed with a keyway, said faces being preferably on a base and two longitudinal side faces of the track.

In an alternative embodiment of the invention, the track will have at least one drive rail which is provided with a toothed rack along the length of the said rail, and the carriage will be provided with at least one drive wheel which has a toothed wheel or pinion adapted to engage said toothed rack to provide drive between said drive rail and said drive wheel.

Preferably, said toothed rack will be secured to said drive rail and will

preferably be located within the hollow profile of said track.

According to another aspect of the present invention, there is provided a machine tool mounted on the carriage of a transport device according to any of the preceding aspects of the invention, for movement on the carriage relative to a workpiece which is fixed with respect to the track.

In the context of this specification, the term'machine tool'is used in general sense to include any tool for performing a cutting, profiling, surface treatment, or any other operation on metal, wood, or any other workpiece or material.

Preferably, said machine tool is a metal cutting device and may comprise, for example, a cutting torch.

According to a further aspect of the present invention, there is provided a method of carrying out an operation on a workpiece by

means of a machine tool according to any of the preceding aspects of the invention, comprising the steps of securing the workpiece and the track of the transport device of the machine tool in fixed relationship to one another and operating the transport device to cause relative movement between the carriage and the workpiece as the operation is carried out on the workpiece.

In order that the invention may be more readily understood, preferred embodiments of the invention will now be described, by way of example only, reference being made to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view of one example of a portable flame cutting apparatus, comprising one embodiment of the invention, with a carriage mounted above a pair of drive rails of a hollow profile track; Figure 2 is another perspective view of the portable flame cutting apparatus, with the carriage mounted within the hollow profile track and engaging the drive rails;

Figure 3 is a view of part of the apparatus in the direction of arrow A in Figure 2; Figure 4 is an and view of the portable flame cutting apparatus shown in Figure 2; Figure 5 is a perspective view of part of the hollow profile track and showing an alternative embodiment thereof ; and Figure 6 is an end view of the drive wheel of the carriage and showing an alternative embodiment of said drive wheel and for use with the hollow profile track shown in Figure 5.

Referring to the drawings, and firstly to Figure 1, the portable flame cutting apparatus 1 comprises a carriage 2 which engages with a track 3. The track has a hollow profile which is partially defined by two parallel drive rails 4, each of which is formed with a series of holes or apertures 5.

The carriage 2 is provided towards one end thereof with a pair of drive wheels 6, each of which has a plurality of radial projections or

studs 7 which engage the holes or apertures 5 in the drive rails 4. The carriage 2 is provided towards an opposite end thereof with a pair of free wheels 8. The drive wheels 6 are mounted on a common drive shaft 10, together with a pair of additional wheels 9 of larger diameter. Similarly, the free wheels 8 are mounted on a common axle, together with another pair of additional wheels 9A of larger diameter.

The opposite wheel 6,8 of each pair that is not visible in Figure 1 is arranged substantially symmetrically with that wheel 6,8 that is visible, on the opposite side of the carriage 2.

The carriage 2 is shown in Figure 1 resting on top of the track 3, with the drive wheels 6 engaging with the drive rails 4 and the free wheels 8 resting on the drive rails 4. An electric motor (not shown) transmits drive to the drive shaft 10 in order to cause the drive wheels 6 to rotate. A hydraulic, pneumatic or other suitable motor may be used as an alternative to the electric motor. The projections or studs 7 on the drive wheels 6, which are at the same pitch and spacing as the holes or apertures 5 in the drive rails 4, engage the holes or apertures 5 and,

as the wheels 6 are rotated, the carriage 2 is propelled along the track 3.

A flame cutting torch 12 is supported on the carriage 2 and is disposed to one side of the track 3. The torch 12 is carried on a shaft 13 which is formed with a rack which engages with a pinion in a gearbox 14, such that the distance of the torch 12 from the one side of the track 3 may be varied and adjusted. Gas is supplied to the torch 12 via tubes 21 which are connected to a valve and/or control box (not shown), which may be mounted on the carriage 2.

Thus, as seen in Figure 1, the carriage 2 may be propelled along the track 3 at a desired rate by means of the electric motor. The torch 12 may then cut a straight line in a sheet of metal to which the track 3 may be clamped. In this way, an accurate cut may be achieved readily and quickly, using relatively unskilled labour.

Also mounted on the carriage 2 is a manual gearbox which has an

upstanding shaft 15 to which a handle may be fitted. On rotating the handle, the shaft 15 rotates with it and causes rotation of a worm or other gear to transmit drive to the drive shaft 10 and thereby turn the wheels 6 to drive the carriage 2 along the track 3. In this way, manual propulsion of the carriage 2 may be achieved at a slow, relatively steady rate, even when there is no external power source to drive the drive shaft 10, or in the event that such power source fails. The carriage 2 is also provided with a handle 23 by which the carriage may be propelled manually.

With the carriage mounted on top of the track 3 as shown in Figure 1, there may be improved traction, as compared to a conventional friction drive, and the drive is reliable, even up an incline. However, when used as shown in Figure 1, it is thought that the apparatus may suffer the disadvantage of many conventional machines, in that the carriage may tip off the track 3, particularly if a large rotational loading is applied to or by the torch 12. This may be particularly troublesome where it is desired to make a cut at a greater distance

from the track 3.

To overcome this difficulty, the carriage 2 is alternatively disposed within the hollow profile of the track 3 as shown in Figures 2 to 4. In this arrangement, the additional wheels 9 and 9A support the carriage 2 on the base 16 of the track 3, and the studded drive wheels 6 engage the respective drive rails 4 from below. Optionally, further perforated drive rails 22 are provided on the base 16 of the track 3, one under each of the studded drive wheels 6, to engage with the drive wheels 6.

In this way, a very stable and reliable transport device is provided for the cutting torch 12. The studded wheels 6 engage the drive rails 4 to provide a positive and accurate drive in either direction along the track 3. Because the carriage 2 is at least partially disposed within the hollow profile of the track 3, it is prevented from tipping out of engagement with the track 3. Thus, relatively heavy torches such as 12 may be employed and/or the torch 12 may be placed at a much

greater distance from the track 3 than is possible with conventional machines.

It is to be noted that the track 3 is provided with keyways 18-to receive fastening devices (not shown)-in each of three outer faces of the track 3. Thus, referring now to Figure 4, one keyway 18 is provided in an outer surface of the base 16 of the track. Another respective keyway is provided in the outer surface of each of the longitudinal side walls 17 of the track 3. Thus the track may be secured to a workpiece or other structure in many different, convenient ways.

It will be appreciated that manufacture of the track 3 may be relatively inexpensive. It is preferably extruded from aluminium (or other suitable metal or alloy). The holes or apertures 5 may be provided as a single row or series (as shown) in each drive rail 4, or may be provided as two or more rows or series side by side (optionally staggered) and may readily be formed by punching. Any

such punching is preferably carried out in an upward direction (as seen), so that the holes or apertures 5 may be formed with a slight bevel or chamfer from below, in order to assist location of the studs 7 in the holes or apertures 5. The holes or apertures 5 may be formed otherwise with chamfers, underneath and/or above. The holes or apertures 5 may be oval or elliptical in shape, with their longer dimension at right angles to the direction of extent of the track 3. This provides a degree of tolerance for engagement of the studs 7 in the holes or apertures 5.

Preferably, the track 3 is of substantial size and mass. When extruded of suitable section of aluminium or the like, this need not make the track 3 particularly expensive. One advantage of having the track 3 of substantial size and mass is that it is strong. Another is that it can have an appreciable heat mass and therefore dissipate a significant amount of heat from the torch 12, thereby providing useful protection for components on the carriage 2. The track may be made in standard lengths which may be joined together-using the keyway 18 in the

base 16 of the track 3, for example-to provide a track of any desired overall length.

The carriage 2 may readily be removed from the track 3, by drawing it out from one of the open ends of the track. The carriage may then be fitted to any desired alternative mechanism-for example, in order to cut circles or other shapes and configurations.

Preferably, the studs 7 taper radially of the respective wheels 6, to assist engagement of the studs 7 in the holes or apertures 5. For example, the studs 7 may be hemispherical, or have at least a part- spherical portion at their ends.

By securing a pair of tracks 3 in parallel, with suitable cross members, and mounting a torch (or any other tool) on a carriage that engages the tracks 3 and is also movable transversely thereof, there may be provided an apparatus in which the torch (or other tool) is movable both up and down the tracks and transversely thereof. By

controlling the movement of the carriage both along the tracks and transversely thereof, a relatively cheap and portable CNC device may be provided.

Although a portable flame cutting apparatus has been illustrated as one example of the invention, other embodiments of the invention may be used for transport in other machine tools-for example, cutting, general welding, plasma and TIG tools, as well as tools for grinding, drilling, polishing and other tools, to carry out operations on any suitable materials, including metal, wood, plastics and glass.

Transport devices in accordance with the invention may be used for any other suitable transport purposes.

Although in the embodiments of the invention illustrated in and described with reference to Figures 1 to 4, the carriage wheels are provided with holes or apertures, it is possible alternatively to provide holes or apertures in the carriage wheels and projections or studs in the rails, to provide traction between the wheels and the rails.

Referring now to the further alternative embodiment of the invention shown in Figures 5 and 6, and referring firstly to Figure 5, the hollow profile track 24 has keyways in the same positions as shown in Figure 4-two such keyways are indicated by reference numerals 25- and carries a toothed rack 26 which extends along the length of the track and which is secured to an inwardly extending portion 27 of the track 24 by a series of fastening means 28.

The toothed rack 26 will preferably be composed of the same material as the track 24, such material preferably being the same as that disciosed in the previously described embodiment.

For co-operating engagement with the toothed rack 26, the drive wheels 6 of the carriage 2 of Figures 1 to 4 are replaced by a single drive wheel 29 (Figure 6) which carries a pinion or toothed wheel 30 which is adapted to engage with the toothed rack 26 to cause relative movement between the track and the carriage. The other drive wheel of the carriage 2 of Figures 1 to 4 is replaced by a free wheel (not

shown in Figure 6) which is the same as or substantially the same as the wheels 9A in Figure 2.

The portion 31 of the wheel 29 engages the portion 24A of the track- see Figure 5-so as to support the carriage on the track, and the opposed free wheel referred to above, as well as the wheels 9A in Figure 2, serve the same purpose. The portion 32 of the wheel 29-as well as the corresponding portions of the three free wheels-engage the underside surface 33 of the inwardly extending portion 27 of the track (see Figure 5), such engagement serving to prevent or assisting in the prevention of the carriage inadvertently leaving the track in circumstances described earlier in this specification.

Whilst in this embodiment the provision of a single toothed rack 26 and a single pinion or toothed wheel 30 has been disclosed, it will be appreciated that a further toothed rack may be provided at the opposed position of me track, and that a second pinion or toothed wheel, the same as the pinion or toothed wheel 30, may be provided

on the carriage. Further, one or more additional toothed racks may be provided on the inside surface of the base of the track, in which case the carriage would be provided with one or more additional pinions or toothed wheels for engagement therewith.

It will be appreciated that instead of the toothed rack 26 being secured to the track 24, the toothed rack may be formed integrally therewith.

Although in the embodiments of the invention described and illustrated herein the track is stationery and the carriage is movable with respect to the track, it is possible alternatively to make the carriage stationery and cause the track to move with respect to the carriage.

In the context of this specification, the term'wheel'includes any suitable device to provide rolling motion and includes, for example, a single drive roller that engages two spaced, parallel drive rails.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

It will be appreciated that the invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed, or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Finally, the movement of the carriage along the track (s) and/or the movement of the track (s) relative to the carriage, as well as the operation of any tool carried by said carriage, may be computer controlled if desired and where circumstances permit.