GB2098262A - Improvements relating to tools for laying asphalt - Google Patents

Abstract

A heating tool for use in laying or smoothing asphalt or like material has shoe or foot plate 12 which is heated by a burner unit 24. The burner 24 is supplied from a separate fuel tank 40, 41 forming part of a handle 10 and connected to the burner by a pressure pipe 31. A manual pump 43 is provided for pressurising the fuel tank. A thermally insulating sleeve 34 reduces heat transfer up to the fuel tank. The shoe 12 is shaped to provide angular, curved and straight edges to enable the tool to be used for tamping in awkward corners. Alternatively the handle may be pivotally attached to the shoe which may be of elongated or circular form to be used as a smoothing device. <IMAGE>

Description

SPECIFICATION Improvements relating to tools for laying asphalt This invention relates to tools for use in laying or smoothing asphalt or like bituminous road making materials, and is applicable particularly, though not exclusively to hand-held tools for smoothing the marginal edges of asphalt strips laid by a machine, and to tools for use in treating small areas, such as the edges of laid asphalt, or for performing finishing operations on asphalt laid by a machine.

In surfacing or re-surfacing a road with asphalt, tarmacadam or like material which can be spread when heated but which sets firm when cool, a length of heated asphalt is often laid by a machine, the length then being rolled to make it more compact and firm. A second length is then laid immediately adjacent the first length and this is then rolled. Further lengths may be added.

Difficulties are encountered in that marginal edge portions of the lengths may be squeezed laterally by the roller, resulting in edge portions which are thinner than a central portion and an uneven road surface. Also when contacting side edges of two lengths are rolled, they may not form a satisfactory bond because the asphalt in the first length will have cooled to an extent that the roller affects it less than the still-hot asphalt of the second length. An unsatisfactory joint between two lengths will lead to undesirable wear at the joint.

It is an object of the invention to provide apparatus for smoothing surfaces made from asphalt, tarmacadam and the like which may enable some or all of these disadvantages to be reduced or overcome.

Accordingly the invention consists in apparatus designed for use in smoothing road surfaces made from asphalt, tarmacadam and the like comprising a base having a generally flat or smooth undersurface for engaging the surface of the asphalt, built-in self-container heater means for heating the base, and an elongated handle or extended operating means by which the apparatus may be moved over the asphalt road surface manually or by connection to a vehicle.

In conventional practice such hand-tools are provided with heavy metal shoes which are heated over a brazier or other burner before being used, and to save time it is usually necessary to provide a considerable number of tools, some of which are being heated while others are in use. Heating of tools in this manner is unreliable, inefficient, and frequently the tools are damaged by overheating.

It is an object of the invention accordingly to provide a tool for the purpose described which will include a convenient self-contained heating system for maintaining the temperature of the tool in use.

Broadly from one aspect the invention consists in a heating tool for use in laying or smoothing asphalt, or like material, including a shoe or foot plate, a fuel burner arranged above the shoe for heating the shoe, an elongated handle attached to the shoe, and fuel tank mounted on or forking part of the handle, and spaced from the burner and shoe.

In such a tool the fuel burner must be positioned above the shoe, and if the fuel tank is positioned above or in the immediate vicinity of the fuel burner it will tend to overheat. By placing the fuel tank on the handle, usually at some height above the burner, the risk of overheating is considerably reduced.

In one convenient construction the handle is of tubular construction and itself constitutes the fuel tank. This construction is particularly convenient for use with a "punner" or "tamper", where the handle is rigidly attached in a vertical position to the shoe, and must be of appreciable strength and dimensions to allow the tool to be raised and driven downwards onto the asphalt surface. By using a strong tubular handle as a fuel tank considerable economies in cost and weight are achieved.

For this type of heating tool it is preferred that the shoe should have a shape providing two or more different forms of edge profile, such as straight-edged, angular or concave-edged or convex-edged. The tool may be provided with all three forms of profile. This is particularly convenient when tamping asphalt around the edges of a variety of different objects such as man-holes, lamp-posts, and gutters.

According to another preferred feature of the invention the handle may be pivotally attached to the shoe. This is particularly convenient for tools designed to be moved horizontally over the asphalt surface for smoothing purposes, the pivoted handle allowing the tool to be swung laterally or pushed forwardly while the shoe remains in a horizontal attitude. In such cases the handle itself may be a tube of relatively small dimensions and the fuel tank may be attached to the handle. Conveniently a flexible fuel supply line leads from the tank to the fuel burner on the shoe.

With this type of smoothing tool, ideally the base of the shoe will be provided with upturned edges. Thus in one form the tool may be formed so that the ends of the heating shoe are curved up from the base. In an alternative form of tool, the tool may be formed so that the base of the heating shoe is circular and the outer edge is curved upwardly.

The invention may be performed in various ways and preferred embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation through a form of tamping tool according to the invention; Figure 2 is a horizontal section on the line Il-Il in Figure 1; Figure 3 is a sectional side elevation through the lower part of another tool according to the invention with a pivoted smoothing shoe; Figure 4 is a perspective view of a third example, having a pivoted hollow rectangular smoothing shoe, for use in forming asphalt edges; and Figure 5 is a side sectional elevation of parts of a further example of a pivoted smoothing shoe having a circular base.

In the first example illustrated in Figures 1 and 2 the invention is applied to a so-called "punner" which is designed to be lifted manually and driven downwards to provide a tamping effect on the asphalt. The tool comprises an elongated tubular metal handle 10, having a length of approximately three feet, attached at its lower end to a combined burner and shoe unit indicated generally at 11. As seen in Figure 2 the shoe is a metal plate 12 having a profile providing two straight edges 13, 14 meeting at a right angle, one curved convex edge 15 and one curved concave edge 16. A radiussed nose 1 7 is provided between the edge surfaces 1 5, 1 6 and another nose 18 of somewhat smaller radius lies between the edges 1 6 and 13.

This shape provides a large number of possible profiles for use in working close up against fixed objects of all types.

A hollow cylindrical metal flame shield 20 is welded to the upper surface of this shoe 12, the shield having a number of outlet apertures 21 in a ring around its lower edge, above the shoe 12, and a fuel burner 24 is positioned centrally above an opening in the upper part of this shield, from which it is supported by a perforated metal sleeve 25. The burner 24 is arranged to direct a flame downwardly onto a conical steel flame spreader 26 welded to the centre of the upper face of the shoe plate 12. In this example the burner is of the type designed to burn vaporised paraffin (Kerosene), and may resemble conventional vaporising liquid fuel burners as used in blow lamps. Alternatively the burner may be a gas burner designed to burn gaseous fuel from a bottled gas tank.

The combined handle and fuel tank 10 is attached to the upper part of the flame shield 20 by an intervening metal tube 30 which holds the lower end of the tank at an appreciable height above the burner 24, and the lower end of the tank is connected to the burner by a pressure pipe 31. The lower end of this tube 30 is welded to the shield 20, and the upper end is seamed to the lower end of the tubular handle by transverse bolts 33, the two parts being separated by a thermal insulating sleeve 34 which reduces heat transfer upwards into the handle. The upper part of the tube 30 is provided with numerous spaced openings 35 which allow combustion air to enter.

The tube 30 is also rigidly connected to the shield 20 by a number of steel straps 36 welded to the sides of the tube and to the shield, and a collar 37 is welded to the handle 10 and abuts against the upper end of the tube.

The tubular handle 10 has a central portion of reduced diameter, convenient to be gripped manually. The upper and lower portions 40, 41, are of somewhat increased diameter and form with the central portion a continuous elongated fuel tank for the liquid paraffin. This shape is also convenient for raising and lowering the tool. The upper end of the hollow handle is provided with a combined filler plug and pressure relief valve 42, and also a manual pump 43 for pressurising the tank. A pressure gauge (not shown) may be provided if required, and a fuel cock 44 is provided at the lower end of the fuel tank.

The examples of the invention illustrated in Figures 3,4 and 5 are all provided with pivoted handles, having forked lower ends attached to combined burner and shoe units. In each case the handle is of relatively light construction, with a separately formed fuel tank attached to the shaft of the handle, and a flexible fuel line leading from the lower end of the tank to the fuel burner.

In the tool illustrated in Figure 3 the shoe 50 is circular in plan, with its outer edge 51 slightly curved upwards, resembling a frying pan. A cylindrical metal flame shield 52 is secured to the upper face of the shoe, and a vaporising liquid fuel burner 53 is located centrally above the shield, in the same manner as in the previous example. A number of gas outlet openings 54 are provided in the lower edge of the shield, and again a conical steel flame spreader 55 is welded to the upper surface of the shoe 50 to direct the flame outwardly.

The handle of the tool includes a straight tubular shaft 57 having a pair of forked limbs 58 secured to its lower end, the limbs each being pivotally attached to a projecting stud 59 on the side wall of the shield 52. The handle can thus tilt relative to the shoe and burner unit about a horizontal axis, which is positioned as low as possible immediately above the shoe plate, to minimise tilting movements when in used. In this example a separately formed fuel tank 60 is attached by metal straps to the handle 57, and a flexible pressure fuel line 61 leads from the lower end of the tank to the burner 53. The tank is appreciably spaced thermally insulated from the burner.

In the third example illustrated in Figure 4 the shoe of the tool is an elongated rectangular plate with its two ends 65 curved upwards. A second plate 66 lies above and spaced from this lower plate and is welded to the two up-turned ends and also connected to two vertical metal plates 67 extending along the two elongated sides.

Openings 68 between the two plates are provided at each side of each end to allow the flames or hot gases to escape. The tool includes a vaporising burner 70 positioned as in the previous examples within a cylindrical tube 71 fixed to the upper plate 66, over an aperture therein to allow the burner flame to pass downwards into the cavity between the two plates. The tool has a handle 73 with forked lower limbs 74 pivotally attached to the side plates 67 of the shoe, and a fuel tank 75 fixed to the handle has a flexible pressure line 76 leading to the burner.

The tool illustrated in Figure 5 is an alternative to that shown in Figure 3 and again has a shoe which is circular in plan, formed by a base plate 77 having an upturned curved edge 78. A top plate 79 forms an enclosure with the base plate 77 and a gap 80 between the two plates allows for the escape of the heating gases. The top plate 79 is provided with a central opening 81 through which the heating flame from the heater (not shown) will pass to heat the base plate 77 after deflection by a flame spreader 82. Bolted to the top plate 79 is a burner shield 83 also provided with a central opening 84. The burner shield 83 additionally provides a pivotal mounting for a handle 85 held by a pivot pin 86 at both sides of the burner shield 83.A stop 87 limits the upward movement of the handle 85 and the wall of the burner shield 83 itself provides a lower limiting point for rotation of the handle to the position 85A shown in dashed outline. A gripping portion 88 is provided near the top of the handle 85 for ease in manipulating the tool and a fuel tank 89 is bolted to the cross-piece 90 of the U-shaped handle 85.

The heating tool shown in Figure 5 is particularly suited for operating on small areas of asphalt and in particular for heating of the adjacent edges of two areas of asphalt when a hole or small strip has been filled. After heating the joining edges of the areas of asphalt it may be additionally smoothed if necessary by a roller or suitable tool.

The arrangement of the pivoted handle 85 and the burner shield 83 may readily be employed in the device shown in Figure 4 to replace the forked limbs 74 and the cylindrical burner shield 71.

Claims (14)

1. Apparatus designed for use in smoothing road surfaces made from asphalt, tarmacadam and the like comprising a base having a generally flat or smooth undersurface for engaging the surface of the asphalt, built-in self-contained heater means for heating the base, and an elongated handle or extended operating means by which the apparatus may be moved over the asphalt road surface manually or by connection to a vehicle.

2. A heating tool for use in laying or smoothing asphalt, or like material, including a shoe or foot plate, a fuel burner arranged above the base for heating the shoe, an elongated handle attached to the shoe, and a fuel tank mounted on or forming part of the handle, and spaced from the burner and shoe.

3. A heating tool according to claim 2 in which the handle is rigidly attached in a vertical position to the shoe, and is of appreciable strength and dimensions to allow the tool to be raised and driven downwards onto the asphalt surface.

4. A heating tool according to claim 3 in which the hollow shoe has a shaped profile as seen in plan, providing angular, curved and straight edges.

5. A heating tool according to claim 4 in which the hollow shoe has a profile providing both convex and concave edge portions.

6. A heating tool according to claim 2 in which the handle is pivotally attached to the shoe.

7. A heating tool according to claim 6 including a flexible fuel supply line from the fuel tank to the burner.

8. A heating tool according to claim 6 or claim 7, in which the base of the shoe has upturned edges.

9. A heating tool according to claim 8, in which the two ends of the heating shoe are curved up from the base.

10. A heating tool according to claim 8, in which the base of the heating shoe is circular and the outer edge is curved upwardly.

11. A heating tool according to any one of claims 6 to 10, in which the handle is a tube of relatively small transverse dimensions, and the fuel tank is formed separate from but attached to the handle.

12. A heating tool according to any one of claims 2 to 10, in which the handle is of tubular construction and itself constitutes the fuel tank.

13. A heating tool according to any one of claims 2 to 12, in which the burner includes heat transfer means for vaporising a liquid fuel such as paraffin, and the fuel tank includes a pump for pressurising the liquid fuel in the tank.

14. Apparatus according to claim 1 in which the heater means includes a burner jet designed to vaporise and burn a liquid fuel, a fuel tank, and means for pressurising the tank, means for directing the hot combustion gases towards the base, and means for cleaning the jet orifice.

1 5. Heating apparatus for use in laying or smoothing asphalt, or like material, substantially as herein described with reference to the accompanying drawings.