US3053311A - Heated tools - Google Patents

Description

Sept. 11, 1962 w. NOTTAGE 3,053,311

HEATED TOOLS Filed July 20, 1959 59 w. H I g 93 45 9 INVENTOR:

h M LTER NUTTAEB.

t B I15 5 IIEI E a CW United tes te This invention relates to tools for spreading, smooth' ing, scraping, and otherwise arranging or conditioning heated thermoplastic materials such as bitumens, and relates particularly to such implements for use in asphalt highway construction, repair and resurfacing.

Commonly employed road materials are mixtures of variously graded mineral aggregates and a bitumen, generally designated as asphalt or tar. The bituminous component acts as a cement in binding together the particles of mineral aggregate, the latter providing the basic strength and the wearing surface of the road. The tools of this invention are used mostly with asphaltic mixtures, as tars are quite often applied in a cold state, and also, since tars do not stand up as well as the asphalts, and are therefore not as commonly applied. When heated for application, these bituminous materials may be brought within a permissible range of 200 to 350 F.

In road construction there is customarily a foundation course from two and one-half to six inches thick. This may be a heated asphaltic concrete for which tools of this invention are adapted, although the base layer is more often composed of regular Portland cement concrete.

It has been found to be the best practice to place an asphaltic binder course as an intermediate layer upon the foundation base. The binder mixture is of two types, known respectively as open binder and close hinder, the difference being in the grading of the mineral aggregate. As indicated by the name, the close binder contains graded crushed stone and sand in proportions which provide a dense mixture quite free of voids and thereby more suitable for particularly heavy traific. The thickness of the binder layer depends upon the anticipated traffic load and may vary between one and two inches.

The final wearing course or black top of a sheet asphalt pavement consists of a mixture of sand, filler and an asphalt cement. The filler is composed of finely ground rock dust or Portland cement and is desirably of a size which will pass through a 200-mesh screen. A fine graded asphaltic concrete may also be applied to the top wearing course.

In building a road with the three asphaltic layers described, hot mixtures of material are involved throughout the full operation. The foundation course of bituminous concrete may be mixed in place, in which case it is generally referred to as bituminous macadam, or alternately the material may be mixed in a stationary plant. The standard hot-mixed asphaltic concrete is prepared with fine and coarse aggregate and righly eight percent of asphalt at a temperature of 350 F., whereas the socalled cold mixture is handled at a temperature of 200 to 225 F. The heavy mixture for the foundation is conventionally distributed on the road area mechanically by a standard spreading machine. The spreading step is followed by compressing with roller weighing about five tons.

If the base material is unevenly applied or must be spread further into approach ways, along joints and edges, which is usually the case, hand raking of the material precedes the rolling operation. Also for supplemental leveling purposes, hand lutes are utilized. The finishing of the concrete base is generally followed by the deposition of a binder course. The binder ingredients comprise lighter aggregate than present in the concrete base 3,9535 ll Fatented Sept. 11, 1962 and about seven percent asphalt. These materials are intermixed in a twin-pug or a drum mixer. The usual range of temperature is between 275 to 325 F., and the temperature must "be held quite accurately in order for the material to be spread and rolled satisfactorily.

The binder material is customarily mechanically spread, or may be dumped on the finished base in advance of the area to be covered. In the latter procedure, after being shoveled into place, the mixture is raked to a thickness that will, when rolled, give the prescribed final depth. Experienced hand rakers usually need no guide in this operation except possibly a line on the curb at the top of the layer.

The final wearing course must be placed soon after the binder course has been rolled and in no case be delayed beyond the same day. The wearing course composition is conventionally prepared by combining the ingredients of sand, mineral filler, and nine to twelve percent asphalt, in a twin-pug or a drum mixer. The temperature to which tiis material is heated should be around 350 F. which is somewhat higher than that for the binding composition.

The batch for the top wearing course is then mechanically spread or shoveled into place. When shoveled the mixture i thoroughly broken up and spread with rakes and is compacted to the proper thickness by rolling. A light tandem roller is generally used first, and is followed by an eightto ten-ton tandem roller for the final compression.

When hand tools are employed in the above road construction operations, as well as in the building of parking lots, airport runways, railroad crossings, and patch repair work, the heat-softened asphalt components, or more rarely, the warm tar substances, readily stick to the teeth of the rakes and to the contacting surfaces of scrapers and lutes. The material thus tends to rapidly accumulate on the working portions of the tools to a point where they become too heavy for easy handling and ineffective because of clogging of the teeth, and uneven coating of the contacting blades.

The tools consequently must be cleaned either by insertion in a fire to melt and burn off the built-up material, by tedious scraping, or by removing the bituminous accumulation by washing in a solvent. All of these procedures are time-taking as well as being somewhat hazardous.

The broad object of this invention is to provide tools which will remain cleaner when used in conditioning heat-softened materials.

A further object of the invention is to provide tools, of the type having limited material contact portions such as rake teeth or straight edge scraper blades, in which are incorporated heating devices for maintaining the material contacting edges of the tools at an elevated temperature.

Another object of the invention is to provide a tool for conditioning heat-softened material which is composed of a metal of a nature which does not promote adhesion, is light in weight and of a good heat conducting capacity.

These and other objects and advantages of the invention are secured through the association with the tool of a heating means by which the working head of the tool is maintained at a temperature which will melt any heatsoftened material which lodges on it. The attainment of the objects is further promoted through the use of a sturdy metal composition such as certain alloys of aluminum, magnesium and bronze, all having high heat conducting capacity.

The benefits and objects of the invention will be brought out more clearly hereafter in connection with the drawings in which:

FIGURE 1 is a perspective view of an embodiment of my invention in the form of a rake;

FIGURE 2 is an enlarged elevation, partly in section, of the upper end of the handle of the rake of FIGURE 1, the section portion being taken on the line 22 of FIGURE 1;

FIGURE 3 is an enlarged cross section of the head of the rake taken on the line 33 of FIGURE 1;

FIGURE 4 is a partial horizontal section of the head of the rake taken on the line 4-4 of FIGURE 3;

FIGURE 5 is a perspective view of a combination lute and rake embodying features of this invention;

FIGURE 6 is a cross section of the head of the tool of FIGURE 5 taken on theiline 66 thereof;

FIGURE 7 is a perspective view of the head end of a scraper emboding the invention; and

FIGURE '8 is a vertical section of the head of the scraper of FIGURE 7 taken on the line 8-8 thereof.

Referring to the drawings in more detail, in FIGURE 1 is a heated rake 10 embodying one form of the invention. As there illustrated, the rake has a hollow handle 12 which is fastened to the square-sectioned head bar 14 by three rods 15, 16 and 17, joined respectively to brackets 18, 19 and 20 extending from the frame.

As shown in FIGURE 3, the rods are secured to the brackets by bolts 21 and nuts 22. A series of teeth 24 extend downwardly from the cross head member 14 and may be threadedly fastened thereto or may be welded at their upper ends as indicated at 25 in the drawing.

In this embodiment, the handle serves as a gas storage tank to which liquefied gas is admitted through the valve 26 at the upper end of the handle. The fuel 27 is delivered from the handle to a burner nozzle 28 within the head member 14 through an elbow connection 29, an adjusting valve 31, and tube 33.

As may be seen in FIGURE 4, the nozzle 28 has two oppositely positioned discharge orifices 37 and 33. Upon ignition, the fuel emitted from these discharge orifices receives combustion air through a series of ports 46 in the side of the head member. The size of the created flames, which extend toward the ends of the head member 14, may be regulated through control of the fuel flow provided by adjusting valve 31 and by the size and number of the port 40. A flame several inches long is normally adequate to heat the head member and by conduction to heat the teeth as well. With the teeth so heated, the asphaltic road material 43, pictured in FIG- URE 3, will not adhere thereto.

An alternate form of the invention is illustrated in FIGURES 5 and 6. The device 44 there depicted is a combination rake and lute. The head member 45 has a straight lute edge 47 on one side and a serrated tooth formation 48 on the opposite edge portion. A strengthening fin 49 extends from the rear side of the head. The handle 52 is secured to the fin 49 by rods 53, 54 and 55 which are fastened to the fin by bolts 53 and nuts 59.

Bolted to the back of the head 45 is a U-sectioned burner casing 60. While the handle 52 of this implement is also hollow, it does not serve as a fuel supply chamber. Instead, it has at its upper end a connection 62 for receiving a conventional gas cartridge 63. From the connection 62, a tube 65 passes down within the handle and is connected to an exterior elbow 66. Joined to the elbow is a control valve 68 from which a tube 69 delivers the fuel through a connection 71 to the burner nozzle 73. This nozzle also has two opposite discharge ports 74, and the burner casing has air inlet openings 77. The conductivity of the metal carries the heat from the flames emitted from the burner nozzle to the full area of the head member 45 and thereby keeps the asphaltic road material from adhering thereto.

In FIGURES 7 and 8 a third form of the invention is illustrated. This embodiment comprises a heated scrap- 4 er 79. The blade 81 of the scraper has edge brackets 82, 83 and 84 by which it is fastened through rods 86, 87 and (58 to handle 90, only the lower end of the latter being shown.

The burner casing 92 here utilized is a channel member similar to the casing 66 of the combination tool 44 shown in FIGURE 5. The casing is similarly fastened to the blade member 81 by means of bolts 93 and 94, and nuts 96 and 97. The nozzle 98 within the casing 92 receives fuel through the tube 99 which may be supplied from either an. attached cartridge or from a reservoir in the hollow handle 90.

While, obviously, other fuels in liquid or gas form may be effective for supplying the heat required for the tools of this invention, bottled propane and butane are readily available commercially and have a high heat generation value. Of the two, butane is preferred because of its lower vapor pressure which allows the use of lighter gauge metal in the handles and fittings. Where the handles are utilized for fuel storage, they can be filled with the liquefied petroleum gas from a large cylinder. The cartridges for attachment to the tools may be purchased in a charged condition and returned for refilling to the gas dealer.

The temperature at which the implements should be maintained in order to keep them clean will vary somewhat with the asphaltic mixtures involved and also with the state of the weather. Slight adjustment of the fuel valves should provide the right flame arrangement for any situation. A slide valve may be installed over the air supply ports if a variable control of the supply of combustion air is desired.

In addition to highway construction, the scrapers of this invention are very helpful in cleaning trucks and the surfaces of other storage receptacles for asphaltic mixtures and other thermoplastic materials.

From the preceding it may be concluded that tools have been provided by the invention which satisfy the objects and advantages previously recited.

In accord therewith the tools are light in weight, stay clean in operation, use a minimum of fuel and require infrequent additions of fuel.

The invention pertains particularly to tools having a cross-wise head member with teeth or a short blade extending perpendicularly therefrom, a type of tool to which it would not ordinarily be considered possible for feasible to apply heat.

The advantages of the invention are more apparent with heated materials, but are also secured with cold asphaltic mixtures which are sticky at ordinary tempera tures and will therefore adhere to unheated tools.

Various structural features include a hollow head member serving as a burner casing, a burner nozzle near the center of the head member and directing flames therefrom toward the other ends of the head member, direct heating of a portion of the head member and conductive heating of the limited working edge portion or teeth of the tool, and fuel supply through the handle.

Modifications in materials and designs of the embodiments disclosed herein may, of course, be made without departing from the spirit of the invention as defined in the accompanying claims.

I claim:

1. A portable tool for leveling thermoplastic road surfacing material having an elongated handle, a fuel supply chamber within the handle, a working member fixed to the end of the handle, said working member having a fully planar side facing away from the handle and to which the handle is relatively perpendicular, a fuel burner located adjacent the center of the side of the working member to which the handle is fixed, tubing conveying fuel from the supply chamber within the handle to the burner, and means directing the flame of the fuel burner laterally from the center of the side of the working member to which the handle is fixed.

2. A portable tool according to claim 1 in which there are connecting members diverging from the handle by which the working member is fixed to the handle.

3. A portable tool for arranging bituminous road surfacing material having an elongated handle, a fuel supply chamber within the handle, a working head member fixed to the end of the handle, said head member being of flat blade form disposed in a plane to which the handle is perpendicular, a narrow heating casing extending across the head member on the side facing the handle, said casing being ported along one side thereof and open at its ends, a fuel nozzle mounted within the casing at the center thereof, and a conduit delivering fuel from the supply chamber within the handle to the fuel nozzle.

4. A portable tool according to claim 3 in which the Width of the narrow casing is less than half the width of the head member.

5. A tool for arranging road surfacing material, said tool being of the type having a limited edge portion of a cross-wise positioned working member of blade form adapted for contact with the material, said tool characterized by having a long, cylindrical handle, a fuel chamber within the handle, a Working member of a highly heat conductive metal fixed to one end of the handle, and means for delivering fuel from the fuel chamber and applying heat therewith to an area of the Working member spaced from the limited edge portion thereof whereby the conductive metal serves to transfer the heat to the edge portion from the area spaced therefrom, said area constituting a limited, confined portion of the working member, said means for applying heat to the Working member including a comparatively narrow casing attached to one side of the Working member, said casing enclosing the area to which heat is applied.

6. A tool according to claim 5 in which the casing has a U- haped cross section with the open portion of the U positioned against the working member.

References Cited in the file of this patent UNITED STATES PATENTS 816,486 Long Mar. 27, 1906 1,286,600 Johnson Dec. 3, 1918 1,298,200 Gorgey Mar. 25, 1919 2,486,018 Furkert Oct. 25, 1949 2,692,641 Woods Oct. 26, 1954 2,699,614 Welch Jan. 18, 1955 2,782,781 Broyhill Feb. 26, 1957 2,819,756 Schmidt Jan. 14, 1958 2,996,111 Mocerino et al. Aug. 15, 1961

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