GB2156883A - Line marking machines - Google Patents

Abstract

A dry line marking machine comprises a chassis (2) fitted with ground-engaging wheels (6,7), a hopper (15) mounted on the chassis and having an open bottom, endless means (9) mounted on the chassis and arranged such that at least a portion of the upper run thereof is disposed in the open bottom of the hopper whereby, in use, it supports particulate material loaded into the hopper and positively conveys the material through an outlet in a wall of the hopper to one end of the endless means from which it is transferred to means (21) for determining the width of the line to be marked, and thence falls to the ground. <IMAGE>

Description

SPECIFICATION Line marking machines This invention relates to machines for marking lines on sportsgrounds, for example, and has particular reference to such machines utilising dry particulate material, which machines are usually referred to as dry line machines.

There area numberofknown dry line marking machines but they all suffer from the disadvantage that the particulate material used tends to stick rather than flow freely under gravity so that discontinuous lines are produced and once the material has clogged, then the machines are very difficult to push. In one of these known machines the material is gravity fed to a rotary brush which flicks the material to the ground. In another machine, an endless belt is mounted below a hopper, the material falling under gravity from a relatively small hopper outlet to the front end of the belt and being fed by the latter two an adjustable device which determines the width of the line to be marked, from which device the material then falls to the ground. Of course,the clogging problem is aggra- vated if the material is damp.

According to the present invention a dry line marking machine comprises a chassis fitted with ground-engaging wheels, a hopper mounted on the chassis and having an open bottom, endless means mounted on the chassis and arranged such that at least a portion ofthe upper run thereof is disposed in the open bottom of the hopper whereby, in use, it supports particulate material loaded into the hopper and positively conveys the material through an outlet in a wall ofthe hopperto one end ofthe endless means from which it is transferred to means for determining the width ofthe line to be marked, and thence falls to the ground.

Preferably, the endless means is a belt having outwardly-extending ribs which assist in the con veyance ofthe particulate material to the hopper outlet. One ofthefeatures of known machineswhich tends to produce clogging is that of a relativelytall, narrow hopper (i.e. a vertical hopper). According to a preferred feature ofthe present invention, the hopper extends longitudinally ofthe machine so that it is generally longer than it is tall (i.e. a horizontal hopper).

This arrangement not only prevents clogging but also makes the hopperveryeasyto load from a bag or sack of material and also lowers the centre of gravity of the machine which is helpful as regards manoeuvrability.

The hopper outlet is normally provided at the lower end of the front wall ofthe hopper and is adjustable in height two effect metering ofthe material to be discharged from the hopper. The width of line to be marked may be determined by a memberfitted to the chassis below the appropriate end ofthe endless means and having therein an aperture of the required width. If the width needs to be changed, then the member is replaced by another having the appropriately dimensioned aperture. In orderto prevent inadvertent discharge of particular material during transport of the machine, releasable closure means may be provided for the member.The endless means are conveniently driven from at least one of the ground-engaging wheels and clutch means are preferably employed in the drive train in orderto be able to disconnect the drive to the endless means when line marking is not required. Manoeuvrability ofthe machine when marking curved lines may be improved byway of providing each wheel of at least one pair of ground engaging drive wheels with a free-wheeling device so that the wheel on the inside of a curved line to be marked can be disengaged from the drive train.

Alternatively, a split axle may be employed to provide a differential arrangementforthe wheels to the same end.

Normally, two pairs of ground-engaging wheels will be employed with one pair being of larger diameter than the other, the smaller diameter wheels being disposed at ortowards the end of the endless means from which the particulate material is discharged so thatthe line width determining means can be disposed as close to the ground as possible. This prevents the need for any extra measures to be taken to shield the falling material from disturbing air turbulence which might otherwise impairthe accura cyofthe line being marked.

To assist in the free movement of the material from the hopper, agitator means may be provided therewithin, and driven with the endless means orseparately. Also, means such as one or more free hanging chains may be disposed attheforward end ofthe endless means in order to prevent the material packing or clogging in the discharge area.

A dry line marking machine constructed in accordance with the invention will now be described in greater detail, byway of example, with reference to the accompanying diagrammatic drawings, in which: Figure lisa front perspective view of the machine, with certain parts removed, Figure 2 is a side view, to a larger scale, of Figure 1, Figure 3 is an enlarged view of part of Figure 2with certain parts removed, Figure 4is a partial plan viewof Figure 3, Figure 5 is detail, to a larger scale, of part of Figure 4, Figure 5A is a detail of Figure 5, Figure 6 is a section of a detail of Figure 2, and Figure 7 is an exploded view of part of Figure 6.

Referring to the drawings, the dry line marking machine comprises a chassis 1 in the form of a channel member 2 which is open at the top, closed at each end, and closed at the bottom exceptfora cut-away portion 3 adjacent the open end. The channel-shaped chassis 2 extends longitudinally of the machine and carries front and rear axles 4, 5, respectively, fitted with front and rear pairs of ground-engaging tyred wheels 6 and 7, the former wheels being of smaller diameter than the latter.

An endless member, in the form of a ribbed belt 9 is mounted in the chassis member 2 on front and rear rollers 11 and 12 mounted on a shaft 13 and the rear axle 5, respectively, the shaft 13 extending through, and being journalled in, the side walis of the chassis member.

A rectangular hopper 15 is carried by the chassis member 2, the hopper being "horizontal" in that it is longerthan it is tall and extends longitudinally ofthe machine. The hopperwalls slope downwardly from the open top thereof to form an open bottom of smaller dimensions, the side walls terminating in vertically-extending flanges 8 which are secured to the respective sidewalls ofthe chassis member 2. The frontwall ofthe hopper 15 terminates short of the open bottom to provide a hopperoutlet30 (Figures2 and 3).

The longitudinai dimension ofthe open bottom of the hopper 15 is less than the distance between the rollers 11 and 12 so thatthe bottom entirely overlies the belt 9, the upper run of which is disposed in the open bottom. The hopper outlet is adjustable in height bythe provision of a gate 17 slidably mounted on the outside ofthe hopperfrontwall and being retained in the adjusted position by two wing nuts 18 and being movable by a handle 10, these components only being shown in Figures 2 and 3. The wing nuts 18 cooperate with bolts secured to the hopper front wall and passing through respective inclined slots (not shown) in the gate 17.

The front end of the chassis member 2 is fitted with an upwardly inclined cap 20whichterminates adja centthe hopperfrontwall above the outlettherein in orderto provide sufficient space forthe material to be carried through the outlet by the belt9 and thence fall offthe front end ofthe Iatterthrough the space defined between the front end ofthe chassis and the belt. To the front end ofthe chassis 2 there is detachably mounted buy a bolt or other device 19 an L-shaped member which serves to determine the width ofthe line to be marked.One limb 21 ofthe member 19 is a solid plate by which the member is bolted or otherwise secured to the chassis and the other limb 22 is slotted with inwardly inclined plates 23 extending downwardlyfrom the edges ofthe slow which is positioned forwardly of and belowthe hopper outlet.

The limb 22, on assembly, passes th rough a slot 24 (Figure 7) in the bottom ofthe front end ofthe chassis and is supported by the bottom ofthe chassis adjacent the cut-away portion 3 therein.

The endless belt9 is driven directly from one ofthe rearwheels7 so thatthe upper run thereof moves from rearto front ofthe machine. More specifically, the rear axle 5 is in the form of athree-parttube 25,26 and 27 as seen in Figures 4 and 5, which is supported by various bush bearings 28 on a rod 29 and retained thereon by split pins 31. Interposed between thetube portions 25 and 26 is a dog clutch 32 comprising two clutch portions in the form of collars 33 and 34 (Figure 5) surrounding, and attachedto,the respective tube portions.Each collar33,34 has a semi-circular dog 35, the dogs35 engaging each otherwhen the clutch is engaged and being separated to interrupt drive to the belt 9 when the clutch is disengaged. Clutch disengagement is effected by a wedge-sheped member 36 (Figure 5A) which is driven between respective annularflanges 37 on the collars 33,34 by an actuating rod 38.The wedge-shaped member 36 is U-shaped with the opposed limbs being tapered from the intermediate limb (to providethewedge) and being apertured to receive one end 39 ofthe rod 38 which extends at rightangles to the main partofthe rod in a plane at right angles to that in which the other end 41 ofthe rod extends (aiso at right angles to the main part of the rod), the end 41 being journalled in a link 42 carried by a twistgrip 40 mounted on a handlebar 43 disposed at one end of handle supports 44which are attached atthe rearendto the chassis 2.

When the rod 38 is pushed by appropriately rotating the twistg rip 40, the wedge member36 is driven between the flanges 37 to separate the dogs 35 to disengage the clutch, separation ofthe dogs being possible by a slot 45 formed in the outercollar33, the head of a bolt 46 securing the collartothe tube portion 25 engaging the slot to prevent rotational movement ofthecollar33 relative to thetube portion 25 but permitting sliding movementagainsttheaction of a compression spring 47 which forces the dogs back into engagementwhen the wedge member 36 is withdrawn from between the flanges 37. The spring 47 acts between the end ofthe collar33 and the hub of the adjacent rearwheel 7.

The tube portion 26 carries the rear roller 12 around which the belt9 passes and thus drives that roiler, and hence the belt, when the clutch 32 is engaged but not when disengaged. Thethirdtube portion 27 carries a sprocket 48 around which a drive chain 49 passes as will be described.

The hopper 15 is fitted with a hinged lid 51 to prevent ingress of rain and foreign matter both during use and non-use, and is also fitted with a central pointer 52 which enables the operatorto sight the centre ofthe line being marked. Within the hopper 15 there are mounted agitators (Figures 3 and 4) in the form offront and rear pairs of rotary members each comprising a shaft 53 on which are mounted two radially extending and diametrically opposed agitators 54 in the form of a rod or bar having one end 55 extending longitudinally ofthe machine and the other end 56 extending at angletothefore-and-aft axis of the machine, with the ends interconnected by a transverse member 57.The agitators 54Of each pair are arranged so that the inclined ends 56 are adjacent the respective sidewalls of the hopper 1 5, these ends serving generallyto wipe the sidewalls on rotation.

The shaft 53 are journalled in self-lubricating bronze bushes provided in the hoppersidewalls.

The agitators 54 are rotatably driven by the other rearwheel 7 via the chain 49 which extends around sprockets 58 on one end of each of the shafts 53 and the sprocket48 on the rear axle tube portion 27. The chain 49 is tensioned by an eccentric cam 59 of a material having a low coefficient of friction. The sprockets 58 and the chain are on the outside of the hopper 15 and are protected by a shield 61 shown in Figures 1 and 6. With the drive for the agitators 54 being separatefrom that ofthe belt 9, the agitators can rotate so as to keep the material in the hopper in a generallyfluid state even when drivetothe belt 9 is interrupted.

On the underside ofthe chassis 2 at the rear end of the cut-away portion 3 thereofthere is mounted a brush 62 (Figure 6) the bristles ofwhich are in general sealing engagementwith the lower run ofthe belt so asto sweep material therefrom to avoid any build up of material in the bottom ofthe chassis which is both wasteful and likelyto prevent, if not stop, proper operation of the machine.

In order to prevent the material packing at the forward end ofthe chassis 2 as it falls from the belt 9, two lengths of chain 63 are suspended from a rod 60 in the chassis end cap in that area (Figure 6).

In use, the hopper 15 filled with a dry particulate material which normally comes in bags or sacks and thus loading of the machine is readily accomplished with the large hopper opening. The material falls to, and is supported by, the upper run of the belt 9 (which in turn is supported by a plate not shown). When the dog clutch 32 is engaged, the belt 9 is driven from the associated rear wheel 7 and the ribs thereon positively convey the material through the hopper outlet 30 and as it then passes overthefront roller 1 1,the metered material thereon falls to the ground via the slotted limb 22 of the member 19 which determines the width ofthe line to be marked by the material.With the smaller wheels 6 being at the front of the machine, the slotted limb 22 is relatively close to the ground so that there is little likelihood of material falling therethrough being disturbed by air turbulence. In any event, the front wheels 6themselves shield the falling material from the side draughts. When line marking is to be discontinued either because marking has been finished or because a broken line is to be marked, the twistg rip 40 is actuated so as to force the wedge member 36 between the flanges 37 to separate the collars 33,34 and thus disengage the dogs 35. Thus drive to the belt 9 is interrupted but, provided the machine is still being wheeled, the agitators 54 continue to be driven as already explained.

As a result of the differential arrangement of the rear axle 5, the machine is very easily manoeuvred around arcs or circles which may have to be marked.

The agitators 54 help to prevent the material from clogging or sticking and the resulting operation ofthe machine is very smooth. Also the low centre of gravity of the machine arising from the use of a "horizontal" hopper also considerably aids the manoeuvrability of the machine.

The belt 9 is tensioned by moving one of the roller shafts in slots (not shown) provided in the chassis member 2 sidewalls and the belt itself may have ribs of any required dimensions compatible with the material being used. However, ribs having 1.25cm centres and a depth of about 3mm have been found satisfactory.

Claims (22)

1. A dry line marking machine comprising a chassis fitted with ground-engaging wheels, a hopper mounted on the chassis and having an open bottom, endless means mounted on the chassis and arranged such that at least a portion ofthe upper run thereof is disposed in the open bottom of the hopper whereby, in use, it supports particulate material loaded into the hopper and positively conveys the material through an outlet in a wall of the hopper to one end ofthe endless means from which it is transferred to means for determining the width ofthe line to be marked, and thence falisto the ground.

2. A machine according to claim 1 wherein the endless means is in the form of an endless belt having outwardly-extending ribs which assist in the conveyance of the particulate material to the hopper outlet.

3. A machine according to claim 1 or 2, wherein the hopper extends longitudinally of the machine so that it is generally longerthan it is tall.

4. A machine according to any of the preceding claims, wherein the hopper outlet is adjustable in height two effect metering ofthe material to be discharged.

5. A machine according to any of the preceding claims, wherein the width of the line to be marked is determined by a member fitted to the chassis below the discharge end of endless means and having therein an aperture ofthe required width.

6. A machine according to claim 5, wherein the width determining member is detachably mounted on the chassis, whereby it can be replaced by an alternative member having an aperture of different width.

7. A machine according to claim or 6, wherein releasable closure means are providedforthewidth determining memberto prevent inadvertent discharge of material during transit.

8. A machine according to any of the preceding claims, wherein the endless means is driven from at least one of the ground-engaging wheels.

9. Amachineaccording to claim 8,wherein a clutch is provided in the drive train forthe endless means.

10. A machine according to claim 9, wherein the clutch is a dog clutch.

11. A machine according to any ofthe preceding claims, wherein the wheels of at least one pair of ground-engaging wheels are arranged to rotate differentially.

12. A machine according to claim 11, wherein each of said wheels is fitted with a free-wheeling device.

13. A machine according to claim 11, wherein said pairofwheels is mounted on a split axle to provide the differential.

14. A machine according to any ofthe preceding claims, wherein two pairs of ground-engaging wheels are provided with one pair being of larger diameter than the other pair, the smaller diameter wheels being disposed at ortowards the end of the endless means from which the particulate material is discharged, wherebythe distance the material has to fall to the ground is minimised.

15. A machine according to any of the preceding claims, wherein at least one agigator is mounted within the hopperto preventthe particulate material packing in the hopper.

16. A machine according to claim 15, wherein the or each agitator is rotatable and is driven separately from the endless means.

17. A machine according to claim 15 or 16, wherein the or each agitator is shaped so as, in use, generally to wipe an adjacent side of the hopper.

18. A machine according to any of the preceding claims, wherein means are provided atthe end of the endless means from which the particulate material is discharged, said means being operable to prevent material packing in the discharge area.

19. A machine according to claim 18, wherein said means is in the form of at least one chain freely suspended in the discharge area.

20. A machine according to any ofthe preceding claims, wherein means are provided to wipe the lower run of endless means to prevent particulate material being carried round by the endless means.

21. A machine according to claim 20, wherein the wiping means is in the form of a brush.

22. A dray line marking machine substantiaily as herein particularly described with reference to the accompanying drawings.