GB2271797A

GB2271797A - Automatic stud applicator

Info

Publication number: GB2271797A
Application number: GB9222181A
Authority: GB
Inventors: Peter Kenneth Slade; David Nicholas Kilner
Original assignee: BTM
Current assignee: BTM
Priority date: 1992-10-22
Filing date: 1992-10-22
Publication date: 1994-04-27
Also published as: GB9222181D0

Abstract

A travelling automatic stud applicator (4) for applying road studs (10) to a road surface comprises feed means for feeding road studs (10) sequentially to a standby position (P) adjacent the road surface and a stud placing device (56) for engaging a road stud (10) at the standby position (P) and pressing that road stud (10) onto the road surface. Drive means (54) are provided for periodically operating the placing device (56) and control means (68) are provided for actuating the feed means to advance a road stud (10) to the standby position. The feed means may comprise a feed path for conveying studs to the road surface whilst supported on a continuous strip of material (32) which comprises an adhesive. A hot wire (48) may be disposed at the end of the feed path adjacent the road surface for releasing the portion of adhesive to which each road stud (10) is applied, as that road stud (10) reaches the end of the feed path. <IMAGE>

Description

AUTOMATIC STUD APPLICATOR Road studs are in widespread use as traffic lane markers. For temporary purposes, such as for lane delineation during road works, it is common to use adhesively fixed road studs which are easy to place and do not mark a new road surface.

Such road studs are normally applied individually by hand. This is a labour intensive process and it requires a team of up to ten men to prepare the road and to place the studs. The manual methods are slow and inefficient and suffer from the additional problem of exposing the men working on the roads to the hazards of passing traffic.

EP 0425239 discloses a vehicle for automatically applying temporary road studs to a road surface. The road studs are secured to the road surface using a hot melt adhesive which is applied directly to the road surface. The road studs are subsequently positioned on the adhesive and pressed into the glue automatically as the vehicle advances. For various reasons, many local authorities ban the use of hot melt adhesives for applying studs on new road surfaces. Another problem with this method is that the glue must be heated to a temperature between 1600C and 1900C and so large gas heaters are required to melt the adhesive and to maintain its temperature.

According to the present invention there is provided a method for applying road studs to a road surface from travelling equipment, in which method the studs are conveyed successively along a feed path to the road surface, the studs being supported, while travelling along the feed path, on a continuous strip of material which comprises an adhesive, each stud being separated from the adjacent stud, upon reaching the end of the feed path, by releasing the portion of adhesive material, to which that stud is applied, from the continuous strip.

According to another aspect of the present invention there is provided equipment for applying road studs to a road surface, comprising a feed path for conveying studs to the road surface while supported on a continuous strip of material which comprises an adhesive, and release means, disposed at the end of the feed path adjacent the road surface, for releasing, from the continuous strip, the portion of adhesive to which each stud is applied, as that stud reaches the end of the feed path.

The apparatus preferably comprises an applicator assembly for applying the studs at a regular spacing to the road surface. The applicator assembly may comprise a ground contact wheel, and it may be provided with a stud contacting foot for pressing each stud on to the road surface.

In a preferred embodiment, the adhesive strip is advanced to convey the studs along the feed path. The continuous strip may comprise a compound tape having a central layer of adhesive material sandwiched between two release tapes made from non-adhesive material.

With the adhesive strip in this form, the adhesive may be advanced by applying traction to the release tapes.

For example, the release tapes may be separated from the adhesive material and drawn on to winding means which is driven to advance the adhesive strip. Release of each portion of adhesive from the continuous strip may be achieved by severing the adhesive.

In an alternative embodiment, the continuous strip may comprise a backing tape to which is applied discrete adhesive portions, each portion corresponding to an individual road stud. Release of each adhesive portion can then be achieved by progressively removing the backing tape.

The winding means may comprise a first drum for removing one of the release tapes to expose the adhesive strip for receiving the studs. A second winding drum may be provided for removing the other release tape to expose the adhesive strip for contact with the road surface.

In operation, the winding drums are preferably actuated intermittently to advance the adhesive strip to a position in which the next stud is presented for application to the road surface.

The equipment in accordance with the present invention preferably comprises a magazine for receiving a supply of these studs to be dispensed one at a time onto the exposed surface of the adhesive strip. The magazine may accommodate the studs in the form of a stack, the adhesive strip passing beneath the magazine so that the studs are applied to the adhesive strip under gravity.

The severing of the adhesive strip to separate the studs is preferably achieved by means of a hot wire.

In a preferred embodiment, the hot wire is disposed beneath the feed path, and means is provided for depressing the two studs at the end of the feed path adjacent to the road surface so that the adhesive strip is brought into contact with the hot wire.

For a better understanding of the present invention, and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a side view of a lorry fitted with an automatic stud applicator; Figure 2 shows a top view of the lorry and applicator of Figure 1; Figure 3 shows an enlarged side view of the road stud applicator; Figure 4 shows an enlarged side view of the road stud applicator; and Figure 5 shows an enlarged side view of a second embodiment of road stud applicator, The lorry 2 shown in Figures 1 and 2 is fitted with detachable road stud applicator equipment 4, comprising a road preparation assembly 6, a magazine 8 of road studs 10, an operating station 12 manned by an operator 14, a spool 16 of bitumen adhesive, and a road stud applicator head 18.As well as the operating station 12, the main bed of the lorry carries further supplies of adhesive spools 16A and road studs (not shown).

In more detail, the road preparation assembly 6 comprises a burner assembly 19 which receives compressed air from a compressor 20 and LPG gas from a gas cylinder 22 to provide a hot blast of air. The hot air jet is approximately 10 to 15 cm wide and is applied to the road surface as close to the stud applicator head 18 as is practicable.

Referring to Figures 3 and 4, the applicator head 18 comprises a sub-frame 23 supported on front and rear wheels 53 and 54. The sub-frame 23 carries the spool 16 of bitumen adhesive, the lower end of the stud magazine 8, and a support plate 26. The support plate 26 can swing relatively to the sub-frame 23 about a substantially horizontal pivot pin 28 at one end of the plate 26. A spring 30, acting between the sub-frame 23 and the plate 26, provides an upwards bias which holds the support plate 26 against the base of the stud magazine 8.

The bitumen adhesive is in the form of a tape 32 approximately 100 mm wide and 75 m long which is sandwiched between two paper release tapes 36 and 40 and is wound onto the spool 16. The spool 16 is mounted on an axle 15 and is held in place by a quick release hand wheel (not shown) for easy exchange of the spool by the operator 14.

The adhesive tape extends from the spool 16 and passes beneath a guide roller 34 supported on the subframe at a position just above the top surface of the support plate 26. The upper paper release tape 36 is separated from the adhesive tape 32 at the guide roller 34 and is wound on to a take-up roller 38. The lower layer of paper release tape 40 and the layer of adhesive tape 32 pass together over the support plate 26 to the end 39 furthest from the pivot pin 28, at which point the lower paper release tape 40 is separated from the adhesive layer and passes beneath the plate 26. The release tape 40 runs over a guide roller 44 and is wound on to a second take-up roller 46. The tape-up rollers 38 and 46 are driven by an electric motor 24.The adhesive tape 32 projects from the end of the articulated pressure plate 26, having picked up a road stud 10 from the magazine 8 (explained later), and passes over a hot wire 48.

The stud magazine 8 comprises a parallel sided tube of rectangular cross-section, and receives a stack of road studs 10. The stud magazine 8 would normally hold between 30 to 100 road studs 10 stacked one above the other. Although not shown, a mechanism may be provided for recharging the magazine 8 as studs 10 are drawn from it.

The magazine 8 is situated over the support plate 26 and so the adhesive tape 32, with the upper release paper 36 removed, runs beneath the open lower end of the magazine 8. As the adhesive tape 32 passes beneath the magazine 8, the studs 10 are deposited on the tape 32 one at a time. A fouling ledge 50 is fixed to the leading face (in the direction of tape travel) of the magazine at a height just sufficient to ensure that only the trailing edge of the bottom stud in the stud magazine 8 rests on the top face of the moving stud beneath it. This aids correct positioning of the stud on tlie apB 32 and minimizes tne frictional forts between the stationary and moving studs.

The rear wheel 54 carries a road stud placing assembly 56. The assembly 56 comprises a stud placing foot 62 which is adapted to contact the top surface of the road stud 10 and press it on to the road surface.

The placing foot 62 is mounted on a shaft 60 which runs in a bush 58 secured to the wheel 54. The shaft 60 is disposed radially of the wheel 54. A spring 64 is disposed between the stud placing foot 62 and the bush 58 in order to bias the road placing foot radially outwardly and in order to provide some compliance, so that when the road stud placing foot 62 contacts the top of a road stud, the shaft 60 moves within the bush 58, so that a controlled pressure is applied to the road stud 10. The tension in the spring can be adjusted so as to vary the controlled pressure.

The wheel 54 also carries a first cam 66 which cooperates with a micro-switch 68 fixed to the subframe of the road stud applicator head 18, and a second cam 70, which cooperates with a follower rod 71 mounted on a rod 72 which projects upwardly from the plate 26 at the end away from the pivot pin 28.

A stud retaining bracket 27 is mounted on the upper surface of the support plate 26 at the opposite end to the pivot pin 28. A first micro-switch 29 is mounted on the sub-frame near the magazine 8 and is adapted to detect the passage of road studs 10 along the upper surface of the support plate 26.

In use, the vehicle 2 is driven at low speed along a road surface to which the road studs 10 are to be applied.

Hot air issuing from the burner 19 warms and dries out the road surface to enhance the prospective adhesion band. Forward movement of the vehicle 2 causes rotation of the stud applicator wheel 54 and when the cam 66 contacts the micro-switch 68 a signal is sent to the electric motor 24 causing it to rotate the take-up rollers 38 and 46, so advancing the tape 32 from the tape spool 16. Winding of the upper paper release tape 36 on to the take-up roller 38 exposes the upper surface of the adhesive tape 32. As the tape 32 passes beneath the magazine 8, the leading edge of the bottom road stud in the road stud magazine 8 adheres to the upper surface of the adhesive layer and is entrained with the tape 32, causing it to be pulled from the fouling ledge 50 and, drop onto the adhesive tape 32.The next road stud in the stack then drops until its trailing edge is arrested by the fouling ledge 50 and its leading edge is arrested by the top surface of the preceding road stud 10.

Thus as the adhesive tape 32 advances, successive road studs 10 drop from the magazine 8 onto the adhesive tape 32 and are pulled from the bottom of the magazine towards the wheel 54, forming a continuous line of road studs on the adhesive tape 32.

The micro-switch 29 responds to the passage of each road stud as it travels along the support plate 26. As each road stud 10 approaches the end of the plate 26, so that it is positioned beneath the stud retaining bracket 27, the micro-switch 29 is tripped and the electric motor 24 is switched off to stop the adhesive tape 32. As shown in Figure 4, this leaves the endmost road stud 11 in a placement position P in which it is close to, or in contact with, the road surface. The adjacent road stud 13 is below the stud retaining bracket 27. With the studs 11, 13 in these positions, the hot wire 48 is positioned exactly beneath the portion of adhesive tape which interconnects them. Rotation of the wheel 54 brings the placing foot 62 into contact with the road stud 11 in the placement position P.At approximately the same time, the cam 70 contacts the follower 71 and a downward force is applied to the support plate 26, causing it to pivot about the pivot pin 28 against the action of the spring 30. This causes the stud 11 to assume a more horizontal position in relation to the road surface. The road stud 13 is simultaneously pulled downwards by the stud retaining bracket 27. The action of the placing foot 62 has the effect of drawing the portion of adhesive tape 32 which interconnects the endmost and following road studs 11, 13 over the hot wire 48 and thereby separates the studs 11, 13, and at the same time presses the outermost road stud 11 firmly onto the road surface.

Shortly afterwards, rotation of the wheel 54 brings the cam 66 into contact with the micro-switch 68 and the motor 24 is re-started to advance the adhesive tape 32 until the micro-switch 29 detects that another road stud 10 has moved beneath the stud retaining bracket 27. Thus, successive road studs 10 are withdrawn from the magazine to pass beneath the stud retaining bracket 27 into the placement position P.

If necessary (for example in cold weather), the adhesive tape 32 may be heated in order to condition it. This may be achieved by electrically heating the plate 26.

To vary the spacing of the road studs, the diameter of the wheel 54 can be altered, or the wheel 54 may be provided with more than one placing assembly 56. In one possible preferred embodiment, not illustrated, two road stud contacting assemblies 56 are provided on the wheel 54 at 1800 spacing, giving a spacing of 1 metre between studs.

In the embodiment of Figure 5, the wheel 54 is replaced by an alternative form of wheel 76. In this embodiment, the road stud placing assembly 56 is replaced by a projection 78 which engages each stud 10 in turn and presses it against the road surface. The micro-switch 29 is replaced by a photo cell 80 which detects when the endmost stud 82 is in the placement position P (i.e. in the position in which the joint between the endmost road stud 82 and the following road stud 84 is situated directly above the hot wire 48).

Cutting of the adhesive tape 32 which interconnects the endmost road stud 82 and the following road stud 84 is caused directly by the eccentric projection 78 on the wheel 76 engaging the endmost road stud 82 and pushing it downwardly relative to the hot wire 48. In this arrangement, a stud retaining bracket 27 is not required, since sufficient support of the following road stud 84 is provided by the base of the stud magazine 8. The support plate 26 is replaced by a rocking plate 86 carried by a spring-biased pivotable arm 88. This allows the following stud 84 to deflect downwardly when the endmost stud 82 is depressed by the projection 78, to cause the hot wire 48 to cut the adhesive tape.

Claims

1. Travelling equipment for applying road studs to a road surface comprising: feed means for feeding road studs sequentially to a stand-by position adjacent the road surface; a stud placing device for engaging a road stud at the stand-by position and for pressing that road stud onto the road surface; drive means for periodically operating the placing device to perform a stud placing operation; control means responsive to the drive means for actuating the feed means to advance a road stud to the stand-by position between two successive stud placing operations.

2. Travelling equipment as claimed in claim 1, in which the drive means comprises a wheel on which the placing device is supported.

3. Travelling equipment as claimed in claim 2, in which the placing device is biased outwardly from the rotary axis of the wheel.

4. Travelling equipment as claimed in any one of the preceding claims, in which the placing device comprises a spring biased plunger for pressing the stud onto the road surface.

5. Travelling equipment as claimed in any one of claims 2 to 4, in which the placing device is one of a plurality of placing devices provided around the circumference of the wheel.

6. Travelling equipment as claimed in any one of the preceding claims, in which the control means comprises a detector which is actuated in response to displacement of the placing device.

7. Travelling equipment as claimed in any one of the preceding claims, in which the feed means comprises a feed path for conveying studs to the road surface while supported on a continuous strip of material which comprises an adhesive, release means being disposed at the end of the feed path adjacent the road surface for releasing, from the continuous strip, the portion of adhesive to which each stud is applied, as that stud reaches the end of the feed path.

8. Travelling equipment as claimed in claim 7, in which the continuous strip comprises a compound tape having a central layer of adhesive material sandwiched between two release tapes made from non-adhesive material.

9. Travelling equipment as claimed in claim 8, in which the feed means advances the adhesive by applying traction to the release tapes.

10. Travelling equipment as claimed in claim 9, in which the feed means comprises winding means on which the release tapes are wound, whereby rotation of the winding means advances the adhesive strip.

11. Travelling equipment as claimed in claim 10, in which the winding means comprises a first drum for removing one of the release tapes to expose the adhesive strip for receiving the studs and a second winding drum for removing the other release tape to expose the adhesive strip for contact with the road surface.

12. Travelling equipment as claimed in any one of claims 7 to 11, in which a magazine is provided for receiving a supply of studs to be dispensed sequentially on to the exposed surface of the adhesive strip.

13. Travelling equipment as claimed in claim 12, in which the magazine accommodates the studs in the form of a stack, the adhesive strip passing beneath the magazine so that the studs are applied to the adhesive strip under gravity.

14. Travelling equipment as claimed in any one of claims 7 to 13, in which severing means is provided for releasing each portion of adhesive from the continuous strip.

15. Travelling equipment as claimed in claim 14, in which the severing means comprises a hot wire.

16. Travelling equipment as claimed in claim 15, in which the hot wire is disposed beneath the feed path, and means is provided for depressing the two studs at the end of the feed path adjacent to the road surface, so that the adhesive strip is brought into contact with the hot wire.

17. Travelling equipment for applying road studs to a road surface, comprising a feed path for conveying studs to the road surface while supported on a continuous strip of material which comprises an adhesive, and release means, disposed at the end of the feed path adjacent the road surface, for releasing, from the continuous strip, the portion of adhesive to which each stud is applied, as that stud reaches the end of the feed path.

18. A method for applying studs to a road surface from travelling equipment, in which method the studs are conveyed successively along a feed path to the road surface, the studs being supported, while travelling along the feed path, on a continuous strip of material, which comprises an adhesive, each stud being separated from the adjacent stud, upon reaching the end of the feed path, by releasing the portion of the adhesive material, to which that stud is applied, from the continuous strip.

19. Travelling equipment for applying road studs to a road surface, substantially as described herein, with reference to, and as shown in Figures 1 to 4 or Figure 5 of the accompanying drawings.

20. A method for applying road studs to a road surface from travelling equipment, substantially as described herein, with reference to Figure 1 to 4 or Figure 5 of the accompanying drawings.