FIELD

[0001] The present invention relates to paint curing systems, in particular to a paint curing system for a vehicle repair

workshop .

BACKGROUND

[0002] A number of paint curing systems are used in vehicle repair workshops. The largest systems are highly energy

efficient and comprise a gas, diesel or oil heated booth in which the car is placed and which is kept at high temperature by convection heating. Where only a small part of the car is being painted, this is highly energy inefficient and time-consuming. Another system utilises a gantry arrangement containing

shortwave infrared lamps which the car passes underneath or which pass over the car, or an installed overhead rail over which a drying lamp travel is and is manipulable into various orientations to cover desired parts of the car. Such gantry or rail systems are expensive to install and operate. Other mobile small systems use a number of stationary infrared lamps and are placed next to the recently painted section of the vehicle . Such systems must be placed at a substantial distance from the surface to be treated to avoid hotspots . As a result,

substantial energy is wasted and typically uneven heating can be a problem.

[0003] There is therefore a need to provide an improved paint curing system for a vehicle repair workshop. SUMMARY OF THE INVENTION

[0004] According to a first broad aspect of the invention there is provided a mobile paint curing unit for a vehicle repair workshop, comprising:

one or more curing heat or radiation sources ; and

a powered drive mechanism on which the curing heat or

radiation source (s) is/are mounted, the drive mechanism being configured to repeatedly pass the curing heat or radiation source (s) over a stationary painted surface of a vehicle

requiring curing, so as to evenly cure the painted surface; and wherein the unit rests on the floor in normal use and is sufficiently compact so that it is able to be located manually next to the painted surface and to be relocated manually from one vehicle to another within the repair workshop as needed.

[0005] In one embodiment, the drive mechanism drives the curing heat or radiation source (s) so as to pass repeatedly over the surface along a one-dimensional trajectory. The drive mechanism may comprise one or more lead screws attached to screw shafts for driving the curing heat or radiation source (s) so as to pass repeatedly over the surface along the one-dimensional

trajectory. The drive mechanism may be operated by a motor rotating the screw shaft (s) so that the lead screw (s) move back and forth between limit positions .

[0006] In one embodiment, the curing heat or radiation source (s) comprises an infrared or ultraviolet lamp.

[0007] In one embodiment, the curing heat or radiation source (s) comprises an elongate infrared lamp disposed generally

transverse to the one-dimensional trajectory. [0008] In one embodiment, the one-dimensional trajectory is generally vertical and the unit is adapted to cure a side surface of the vehicle . The curing heat or radiation source may comprise a radiant lamp directed partly downwards so as to enable curing of upwards facing upper surfaces of a mudguard of the vehicle as well as sidewards facing surfaces of the

mudguard.

[0009] In another embodiment, the one-dimensional trajectory is generally horizontal and the painted surface is an upper surface of a bonnet, roof, or trunk of the vehicle. The generally horizontal one-dimensional trajectory may be provided by a lead screw moving horizontally in response to a generally horizontal screw shaft. The generally horizontal screw shaft may be

disposed within a beam attached through a second lead screw to a generally vertical screw shaft to allow vertical movement of the generally horizontal screw shaft.

[0010] In another embodiment, the one-dimensional trajectory is generally vertical and the curing heat or radiation source comprises a lamp system directing radiation in different

directions and arranged so that different facing sides of a corner of the car can be cured.

[0011] In one embodiment, the unit further comprises a set of wheels to enhance mobility of the unit.

[0012] In accordance with a second broad aspect of the invention there is provided a method of curing the painted surface using the mobile paint curing unit of the first broad aspect of the invention, the method comprising the steps of:

wheeling the unit suitably close to the painted surface requiring curing; positioning and/or configuring the unit so that the drive mechanism can repeatedly pass the curing heat or radiation sources over the painted surface so as to evenly cure the painted surface; and

operating the drive mechanism for a sufficient curing time.

BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a perspective drawing room of an embodiment of the invention adapted for curing vertical panels such as mudguards or doors ;

[0014] Figure 2 is a cross sectional drawing of the embodiment of figure 1 showing the inner workings .

[0015] Figure 3 shows the embodiment of figure 1 in use during a front mudguard.

[0016] Figure 4 is a perspective view of another embodiment of the invention adapted for curing upwards facing horizontal surfaces such as bonnets, trunks, and roofs.

[0017] Figure 5 is a view from above of another embodiment of the invention adapted for curing both faces of a corner of the vehicle .

DETAILED DESCRIPTION OF EMBODIMENTS

[0018] Embodiments of the current invention will now be

described. [0019] Referring first to Figure 1, the exterior view of an embodiment is shown in perspective adapted for curing relatively vertical surfaces such as doors or mudguards ("wings") . The unit 100 comprises a housing 10 having a digital control Panel 11 and slot 40. Curing heat or radiation source 20 in the form of an elongate shortwave infrared lamp is attached in a slightly downward angle orientation to a support arm 30 which moves up and down slot 40 by an electrically powered drive mechanism powered through standard power supply cable 70. Housing 10 rests on a base 50 equipped with castor wheels 64 for locating unit 100 next to a painted surface requiring curing or for moving between vehicles . The unit is about 1.4 m in overall height from floor to top and other dimensions are to scale.

[0020] Referring now to figure 2, the same unit 100 is shown in cross-section with working parts including the drive mechanism revealed. Support arm 30 engages via lead screw 31 with screw shaft 80 which rotates inside bearings 81 and 82 at either ends thereof, in either direction to impart vertical motion upwards or downwards of curing lamp 20 so that the curing lamp 20 passes over a surface to be painted repeatedly along a one-dimensional trajectory. Screw shaft 80 is turned by electric motor 85 in a given direction until limit switch 83 or 84 is activated by contact with lead screw 31. Support arm 30 also engages through sliding bearing 32 on parallel guide rail 90 secured at either end 91 and 92 of housing 10. Curing lamp 20 comprises shortwave infrared heating element 21 reflecting off parabolic reflector 22 to impart a directional radiation beam onto the surface to be cured. Lamp 20 also comprises a safety grille 23 and fixing arm 24 which attaches to support arm 30 via angle-adjustable joint 25, shown in this diagram in a slightly downward angled

configuration .

[0021] Referring now to figure 3, unit 100 of figure 1 and figure 2 is shown in use curing upwards facing 220 and sidewards facing 210 parts of a mudguard of vehicle 200. The unit 100 is positioned so that the natural distance between curing lamp 20 and the surfaces 210 and 220 at closest approach on the one- dimensional trajectory is sufficiently close to provide a curing temperature but sufficiently far to prevent overheating, taking into account the speed of movement of lamp 20 along slot 40. The slightly downward angle of lamp 20 enables curing of both generally upwards facing surfaces such as the top of the

mudguard 220, as well as sidewards facing surfaces 210.

Operationally, typical appropriate distances for a 2000 Watt shortwave infrared curing lamp is 30 to 45 centimetres, for a travel speed 1 metre per minute over a vertical trajectory of length about 0.92 m. Digital control panel 11 enables setting of a time to automatically switch off the unit after a user- specified time period.

[0022] Unlike conventional mobile units, curing lamp 20 is able to be located quite close to the painted surface due to the fact that it is constantly moving over the surface, enabling a lower powered lamp to be used, saving energy and better directing the radiation more evenly onto the surface where needed and not radiating energy unnecessarily to parts of the vehicle that have not been painted. Further, when lamps of less than about 2200 W are used, the system of the invention can be powered from a conventional low power socket which in some workshop areas is standard.

[0023] Referring now to figure 4, an alternative embodiment is shown particularly adapted to curing flat surfaces of a vehicle such as a roof, bonnet or trunk. Unit 300 comprises extended base 380 which may be partly wheeled under the vehicle. In this embodiment, lamp 360 is generally downwards facing and is connected via support arm 350 to a housing 330 that comprises a slot, screw shaft and the limit switches similar to previous embodiment (not shown) . Housing 330 is also attached through second slot 340 to another vertical screw shaft enabling

vertical motion of lamp 360, primarily for setting an initial height above the bonnet, roof or trunk over which lamp 360 is to be laterally scanned repeatedly. Control mechanisms may be contemplated for this embodiment that enable programmed

simultaneous movement in both dimensions to provide a

curvilinear one-dimensional trajectory, suitable for

particularly curved surfaces .

[0024] Referring now to figure 5, another one embodiment is shown as a concept sketch viewed from above, with housing 410 similar to housing 10 of the first embodiment, and a lamp system comprising lamps 420 and 430 positioned to direct radiation in different directions so different facing sides of corner of the car 250 and 260 can be radiated. Also contemplated are

embodiments of similar functionality to this embodiment which comprise a lamp system of a curved row of a number of point radiation sources to provide radiation on the corners 250 and 260, or embodiments having a lamp system comprising a special purpose elongate light source manufactured in an appropriate curved shape.

[0025] In an alternative variation currently under trial and applicable to all the above examples , guide rail 90 may be disposed on the outside of housing 10 rather than inside housing 10. More particularly guide rail 90 may be disposed on the same face as slot 40, and even more particularly there may be 2 guide rails on either side of slot 40 engaging at either end of the lamp bracket or a branched support arm.

[0026] Persons skilled in the art will also appreciate that many variations may be made to the invention without departing from the scope of the invention.

[0027] For example, while the examples given shown essentially strictly repeated one-dimensional trajectories, more complicated drive mechanisms allowing freedom for multidimensional

trajectories to repeatedly pass over the surface are also within the scope of the invention. Further, any curing heat or

radiation is contemplated other than infrared such as

ultraviolet (conventional or LED) , or convection using hot blowing over the surface. Other types of infrared radiation source such as flameless gas catalytic infrared sources are also contemplated. Also, additional functionality may be included such as the ability to adjust the position of the limit switches to confine the one-dimensional movement to a needed region.

Further still, the electrically powered drive mechanisms of the example shown could be replaced by other forms of power such as pneumatically powered drive mechanisms .

[0028] 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. Further, any method steps recited in the claims are not necessarily intended to be performed temporally in the sequence written, or to be performed without pause once started, unless the context requires it.

[0029] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.