US3160154A

US3160154A - Vehicular-type asphalt roadbed heater

Info

Publication number: US3160154A
Application number: US388019A
Authority: US
Inventors: Clarence W Sowell
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-08-06
Filing date: 1964-08-06
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 c. w. SOWELL VEHICULAR-TYPE ASPHALT ROADBED HEATER 5 Sheets-Sheet 1 Original Filed Feb. 9, 1962 INVENTOR.

CZAFE/VCE 14 Jan/14 wk n ig/4 m AGENT 7 /Ill Dec. 8, 1964 c. w. SOWELL 3,160,154

VEHICULAR-TYPE ASPHALT ROADBED HEATER Original Filed Feb. 9, 1962 3 Sheets-Sheet 2 FIG. 5

FIG.6

INVENTOR. azn z/vce m Jon 14 2mm. MW

Dec. 8, 1964 c. w. SOWELL 3,160,154

VEHICULAR-TYPE ASPHALT ROADBED HEATER Original Filed Feb. 9, 1962 s Sheets-Sheet s 9 77 7a m; I 7'5 75 75 FIG. 9

INVENTOR CZ4FN6E m Jon 14 AGENT United States Patent 7 3,160,154 VEIHCULAR-TYPE ASPHA T RQADBEB HEATER (Ilarence W. Sowell, 16248 Itasca, Sepulyeda, Calif. Continuation of application Ser. No. 172,213, Feb. 9, 1962. This application Aug. 6, 1964, Ser. No. 338,019

12 Claims. (Cl. 126-2712.)

This application is a continuation of application Serial No. 172,213, filed February 9, 1962.

The invention herein set forth pertains to surface heaters, and more particularly to a vehicular type asphalt roadbed heater.

The instant invention is an improvement upon the equipment described in my Patent No. 2,558,160, which issued June 26, 1951, to which reference will frequently be made in this specification; in fact, apparatus therein illustrated and described will not be illustrated and discussed in the present application, excepting in cases where some of the components of the earlier structure are elements of the new combinations embodying the present invention as set forth in the appended claims.

The patent to which reference has just been made disclosed a heater carried by a chassis frame of substantially the maximum width permitted on most city streets, but provisions were therein set forth for moving the heater laterally with respect to the chassis in order to permit greater lateral coverage of the roadbed than the width of the heater would otherwise allow. The increased broadside range of heating made it possible to use the heater closer to curbs and streetcar tracks than would otherwise be the case, and to obtain this additional coverage without any lateral movement of the chassis.

One of the primary objects of the present invention is to extend the lateral coverage in a practical manner beyond the limits permissible with the structure set forth in my earlier patent. This is accomplished by providing the firebox with removable side plates and with pivotally mounted side extensions that may be rotated downwardly at will from a parked position over the hood to a working position in which they for-m continuations of the firebox that greatly expand its width.

Another object is to provide a firebox with hinged side extensions that may be selectively used to provide such different firebox widths that combinations thereof will correspond to the width of the street. This is important because there should be no overlapping of successive passes over the asphalt. If the main hood or firebox is 8 feet wide, four passes without using either of the side extensions will cover a street 32 feet in width, but if the side extensions are 2 feet across, the same street may be covered by two traversais using one side extension to give foot spreads and one traversal with both side extensions down to cover the remaining .12 feet. Or two passes with a total firebox width of 12 feet and one of 10 feet would I also do the job. A street 30 feet wide could be covered in three sweeps using a firebox 8 feet across and one side 1 extension 2 feet wide. And it will readily be seen that streets of various widths up to 48 feet can be covered in no more than four passes. Since most cities will not permit equipment more than 8 feet-wide to move from one job site to another, it would take six traversals of a firebox without selectively usable side extensions to cover the same 48-foot street. I

My mobile heater may also be used for melting snow and ice from thestreets; or for drying them; the latter use having been employed on racetracks; and .it is of course obvious that the adjustable-width feature makes it possible to accomplish -al1'these tasks more economically thanv would otherwise be the case. p

Pursuant tothe uses justsetforth, an important-object of the invention is to provide the hood with hinged side extensions that may be rotated out of the way when their use is not required.

A further object is to provide linkage means operable by the lateral movement of the hood itself for rotating the hinged extensions.

An additional object is to provide the heater or firebox with removable sides for use when the hinged extensions are not required.

Still another object of the present invention is to provide an improved firebox construction that will produce a better spread of the fire.

Yet another object is to reduce the smoke produced by providing an after-burner effect in the the rear part of the hood.

Still other objects will appear as the specification proceeds.

In the drawings:

FIG. 1 is a side elevation of a mobile surface heater embodying my invention.

FIG. 2 illustrates a conventional means that may be used for connecting the chassis of my heater structure to the transporting truck.

FIG. 3 is a cross-section taken on line 33 of FIG. 1.

FIG. 4 is a longitudinal section through my improved firebox or heating hood.

FIG. Sis a section taken on line 5-5 of FIG. 1.

FIG. 6 is a section taken generally on line 6-6 of FIG. 1. I

FIG. 7 is an enlargement of the parts shown within the circle at the left in FIG. 5.

FIG. 8 is a view taken on line 88 of FIG. 7.

FIG. 9 is a section taken on line 9-9 of FIG. 1.

The supporting chassisof my surface heater is a generally rectangular frame 19 of substantially the construction shown in my earlier patent. This rectangular frame may be supported at the rear by two downwardly extending extensions 10b, FIGS. 1 and 3, which are attached to member between the wheels 95. At the front end, individual extensions 19a of the side members of the chassis frame lti may appropriately extend downwardly and inwardly at an angle as shown in FIG. 2, where they are connected to a disc or fifth wheel 97 that is pivotally supported on a mating structure or fifth wheel 93 carried by a truck or tractor 55. Attached to and depending from the side members of the frame 10 are two parallel I-

beams

11 and 12. A shiftable rigging 13 is movably supported on the lower flanges of these I-

beams

11 and 12 by means of roller-bearing equipped

hanger carriers

14, 15, 16 and 17. The rigging 13 comprises two parallel longitudinally disposed I-beams 2t and 21 and two spaced and transversely disposed parallel I-

beams

22 and 23 welded or otherwise rigidly connected to

members

29 and 21 to form a rectangular frame.

The

hanger carriers

14 and 16 are assembled to I-beam 18 which extends across the rigging 13 and is rigidly connected to the longitudinally extending

side members

20 and 21, and

hanger carriers

15 and 17 are in like manner assembled to I-beam cross-member 19 which is also rigidly attached to the'side members. Each of the carrier assemblies comprises two opposed side plates 24 and 25, which are generally triangular in shape. A pair of flanged carrier Wheels are rotatably'mounted on each of the plates 24. and a pair of identical flanged supporting wheels are similarly rotatably mounted on each of the plates 25.

Hanger carriers

14 and 16 are rigidly connected to I-beam cross member 18 by means of bolts 27 and 28, respectively, FIG. 9, which pass through the I- beam. The

hanger carriers

15 and 17 are similarly attached to cross-member 19 by means of

bolts

29 and 30, FIG. 5.

The hanger carriers just described make it possible for the frame or carriage 13, comprising the two

longitudinal members

26 and 21 and the four

cross-members

18 and 19, 22 and 23, to be shifted laterally. T o prevent the hanging carriage from slipping entirely off of the lower flanges of the cross-beams 11 and 12, which act as supporting tracks, I provide two limiting struts, each of which comprises a diagonal arm 31. One arm 31 joins with an abutting section 2, and arm 31 at the right in a similar manner joins an abutting section 33. It will be observed in FIG. 6 that the shiftable carriage comprising

longitudinal members

20 and 21 and

cross members

22 and 23 cannot be moved farther to the left because the longitudinal beam 20 is abutting against section 33. The movement of the carriage to the right is similarly limited by the engagement of I-bearn 21 and the abutting section 32.

Two rotatable shafts 34 and 35 extend all the way across, and overhang the cross carriage 13 as may be seen in FIGS. 1 and '6, the latter figure showing shaft 35 only. Each of these shafts is journaledin a pair of bearings 36, FIG. 6, appropriately attached to the longitudinal beams by a pair of U-bolts 37. v v

The two shafts 34 and 35 are so connected by. link 38 and

lever arms

33 and 40 that they turn as a unit. The lever arm 39 is rigidly attached to shaft 34 intermediate its ends, and lever arm 40 is likewise rigidly connected to shaft 35. The outer ends of these two arms 39 and 40 are pivotally connected to opposite ends of the interconnecting link 38. Lever

arms

41 and 42 are solidly connected to opposite ends of shaft 35, FIG. 6, and a similar set of lever arms 43; and 44 are rigidly attached to opposite ends of shaft 34. The outer end of arm/i1 is pivotally connected to a linkage 45, and arm 42 issim ilarly pivoted to a linkage 46, FIG. 5. Lever 43 is con 'nected to a linkage 47, FIGS. -1 and 6, and the companion lever arm 44 is connected inlikemanner to another such linkage 48. The lower ends of

linkages

45, 46, 47 and 48 are pivotally connected to the top of the heating hood or firebox 49, FIGS. 1 and 4, by means of brackets 50, FIG. 4. It will be obvious that counterclockwise rotation of shafts 34 and 35 will cause the firebox 49 to be raised and that the clockwise rotation of these shafts will lower the firebox. This movement is controlled hydraulically by the cylinder 51 and the piston throw-leverSZ operat-' ing therein. 7 This throw-lever is appropriately pivoted at its outer end to arm 40 by means of arr-interconnecting bracket 53, and the cylinder 51 is itself pivotally mounted to the frame 13 by means of bracket 54. The hydraulic cylinder 51 is operated from the cab 55 by controls shown and described in my Patent No. 2,558,160.

The heating hood or firebox '49 is longitudinally braced and stabilized with respect to the frame 13 by means of a pair of angularly disposed

rods

104 and 105, FIGS. and 6, rod 104 being shown also in FIG.. 1. The upper end of rod 104 is pivotally anchored to 'I-beam 2% of the transversally shiftable carriage'13 by means of bracket 106, FIG. 6, and the corresponding end of the bracing rod 195 is similarly pivotally anchored to I-beam 21 of the shiftable carriage by bracket 107. i v

The cross travel of the laterally movablecarriage is accomplished by means of the hydraulic jack 56 and its plunger 57, PEG. 6, the outer en'd'of which is appropriately interconnected to the cross carriage. As is the case with jack 51-, the jack 56 iscontrolled from the cab by appropriate hydraulic connections, such'as those disclosed in my earlier-patent.

In order to extend the broadside coverageof my heater or hood beyond the limits permitted by my earlier structure, I attach two hinged

extension structures

58 and 59 to opposite sides of the heater 49, as shown inFIGS. 5 and 9. These side extensions are L-shaped in cross-see tionand are pivoted by means of a plurality 'of brackets attached to the cover and theside panel. One or more brackets 63 are attached to the top cover of each hinged extension intermediate its outer wall or side panel 64 and the pivot point 65. A link 66 is detachably connected at one end thereof to one of the brackets 63 on the left side extension 58 and at the other to a bracket 67, which is rigidly attached to one end of one of the cross beams 12 that depend from the chassis frame 10 as shown in FIG. 5.

Such brackets 63 as may be attached to the right pivotal extension 59 are each detachably connected to a bar such as link 68 which is removably pivoted to a bracket 69 on the right end of the cross beam 12. These links are disconnected at at least one end whenever the intermediate carriage and firebox are to be moved laterally and whenever the entire mobile unit is to be moved from one site to another.

When neither of the hinged

side extensions

58 or 59 is being employed during the time that the firebox is in operation, a side plate 70, FIGS. 5, 7 and 8, is hung over the otherwise open side of the firebox. This plate may appropriately be made of A thick heat-resistant stainless steel. The two side plates may be removably hung to the top edge of the open side of the firebox by means of chains 71 or other appropriate instrumentalities;

The structure hereinbefore described makes it possible to raise and lower the extensions solely by the power available hydraulically through the two

jacks

51 and 56. If the distance from the hinge point 65 of either side extension, FIG. 5, to the corner 101 of the top surface and associated side panel 64 is 18 inches and if the bar 66 is 2 feet 3 inches long, then either of the side extensions can be raised or lowered by a two-foot lateral movement of the firebox 49. At the beginning of the raising movement, the

rigid links

66 and 68 may be disposed in somewhat the position of link 68 shown on the right side of FIG. 5. At the end of the movement; the various parts will appear in the positions in which extension 58 and link 66 are shown on the left side of this figure. During the actual raising and lowering'of the sides, however, links 66 and 63 are seldom, if ever, both connected at the same time. One reason for this will be apparent if we consider what would happen if the firebox should be moved to the right from the position shown in FIG. 5 while both links are connected and while the firebox is at the level shown in th'efigure. Any movement of the firebox to the right would obviously result in buckling the link 68. This can of course be avoided by lowering the firebox sufiiciently to cause the link 68 to pull upward on the bracket 63 on the top of the extension structure 59 and rotate the structure far enough counterclockwise about its axis of rotation to permit the lower end of link 68 to swing downward in an are as the firebox is moved to the right. This downward movement of the firebox is not possible, however, so long as rod 66 above the left .side' of the firebox remains connected, as no lowering of the pivot 63 at the bottom end of link 66 can take place for the reason that this would cause link 66 to rotate counterclockwise and the extension 'str'uctiire as to turn clockwise, a movement that is not possible without bending 'or breaking something since the striictur'e 64 is already in its extreme clockwise position But let us suppose link 65 is disconnected. The extension 59 then may-be rotated counterclockwise to 'a 61 attached thereto, each having a pivotal connection with another bracket 62 mounted on top of the firebox. Each of the side extensions has a top cover, a side panel rid-depending" from one edge of the cover, a front element and a back element, each of these elements being position in which it will .rest against the right bracket 72 by first lowering the firebox enough to provide room for a downward swing of the lower end of link- 68 as the fire-- box is moved to the right. This will then of course cause the extension structure-5? to turn clockwiseslightly durcourse first be removed. If we are to lower the extension side structure 58 to its operative position from its rest position shown in FIG. 5, link 68 on the other side of the equipment must first be disconnected at one or both ends. The firebox may then be moved to the right. As it does so, the link 66 will press on pivot 63. Inasmuch as the line of force exerted by link 65 is considerably above the center of rotation 65 of the side extension 58, there is a moment arm to receive the force, and the structure 58 consequently turns counterclockwise in response to the movement of the firebox to the right until the side structure 58 is in an operative position in which its top is aligned with the top of the firebox.

It will be observed in FIG. 5 that the raised extension 58 is so disposed that the portion thereof which extends furthest to the left is almost directly over the plate 70. This indicates that when both extensions are raised, the distance across the entire hood, plus the parked hinged extensions, will be no greater than the distance across the hood itself from one side plate to the other.

When the extensions are raised to the position shown at the left in'FlG. 5, they will rest on the brackets 72, which are attached to the top of the heater.

Other means than the hydraulic power available on the chassis may of course be employed for raising or lowering the extension sides, as, for example, a hand winch mounted on the chassis or firebox, or a skip loader that may be used to lift the extension side by means of its lower edge.

My improved hood, or firebox, provides more even distribution of the heat than is possible with previous structures, and it also reduces smoke by an after-burner ef fect, hereinafter described. In the longitudinal section of my firebox shown in FIG. 4, a bulge 73 is shown in the insulated top section. This forces the flames down against the surface of the road and toward the back end 74 of the firebox. Fuel burning nozzles are of course arranged along the front end as shown in FIG. 9 where a plurality of nozzles F5 may be seen. These are individually inserted in, or aligned with, individually associated openings like opening 76 shown in MG. 4. These nozzles are supplied with fuel through individual tubes 192 connected to the fuel manifold 77. The nozzles are supplied with air through individual pipes 73 connected to an air manifold 79 that communicates through a duct 89, FIGS. 9 and l, with a blower 81 in the truck 55'.

In my improved heater, I provide an auxiliary air manifold 82 in the bulge. This is supplied with air from the main air manifold 79 by means of short pipe 114, elbow 115, pipe 1%, elbow 116 and short pipe 117. A plurality of burners, such as burner 83, each receiving its air from the auxiliarymanifold 82, may be aligned along the bulge '73 where each communicates with the inside of the fire hood by means of duplicates of opening ill. Fuel is furnished to these additional burners by tubes such as tube 12% from the auxiliary fuel manifold 119 which receives its supply through tube 118 from the main fuel manifold 77. These extra burners assist-the combustion of any unburned gases that may have reached the vicinity of the nozzles in the bulge, thus materially reducing the waste caused by unburned fuel and minimizing the fumes and smoke that would otherwise reach the surrounding atmosphere.

ltwill be noted that the top portion of the hood near the end '74, here designated by the numeral 36, slants downward, as does also the thick insulation 37 attached thereto. This directs the, fire and heat downward toward the roadbed under the open side of the hood.

Individual nozzles are provided for the hinged side extensions. One such nozzle, designated by'the numeraldd, is shown in association with side extension 59 in FIG. 9, and an aperture 92 is shown in the end element of the opposite side extension 53 for another nozzle like the one shown on the right side. Nozzle 33 is supplied with air through pipe 89, which is connected by elbow 914to a short pipe Q3 communicating with the air manifold 79.

Before raising the extension 59 nozzle 88 with its supply pipe 89 must be rotated out of the way, the elbow 94 rotating on the short pipe 93 at the juncture of the elbow 94 and pipe 93. Tube 91, which supplies fuel to the nozzle 88, is a flexible tube, and therefore flexes when nozzle 88 and tube 5% are rotated to an inoperative position. The fuel is then turned ofi by means of valve 133.

The hinged side extensions hereinbefore described may of course be used with a mobile chassis having no laterally movable subcarriage, and the improved firebox has increased utility even for such purposes as roasting ore.

Various modifications may of course be made from.

the illustrative embodiments herein described and shown in the drawings, and substitutions of other parts performing the same functions may be made for the various elements set forth in the appended claims. Moreover, transpositions and rearrangements may be made without departing from the broad spirit of my invention.

The inventor claims:

1. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; means for supporting other end of said frame on an axle carried between two wheels; a rig movably depending from said frame for, lateral movement; a firebox disposed beneath said rig and at least indirectly supported thereby, said firebox having an open bottom and comprising a top member, a front wall, a back wall and at least one elongated angularly movable side extension structure hav- ,ing a top cover, a front element, a back element and a side panel depending from one side edge of the top cover,

' said structure being so hinged to said top member that the edge of the top cover opposite from said one side edge lies adjacent one edge of said top member in one angular position of said structure; means carried by said rig for raising and lowering said firebox; a rigid bar removably pivoted at one end to said frame and at its other end to said extension structure intermediate its axis of rotation and its side panel, said bar acting to rotate said extension structure selectively to and from its operating position in response to lateral movement of said rig; and a removable side for the firebox to close the otherwise open side of the firebox when the extension side structure is not being used.

2. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle;

means for supporting the other end of said frame on an,

axle carried between two wheels; a rig movably depending from said frame for lateral movement; a firebox dis.-

posed beneath said rig and at least indirectly supported thereby, said firebox having an open bottom and comprisa having a top cover, a front element, a back element and a side panel depending from-one side edge of the top cover, said structure being so hinged to said top member that the edge of the top cover opposite from said one edge lies adjacent one edge of said top member in one angular position of said structure; means carried by said rig for raising and lowering said firebox; a rigid bar removably pivoted at one end to said frame and at its other end to said extension structure intermediate its axis of rotation and its side panel, said bar acting to rotate said extension structureselectively to and from its operating position in response to lateral movement of said rig; a removable side for the firebox "to close the otherwise open side of the firebox when the extension side structure is not being used; and means for limiting the angular movement of said extension structure when it is rotated to an inoperative position over said firebox.

3. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; means for supporting the other end of said frame'on an axle carried between two wheels; a rig movably depending from said frame for lateral movement; a firebox disposed beneath said rig and at least indirectly supported thereby, said firebox having an open bottom and comprising a top member, a front wall, a back wall and at least one elongated angularly movable side extension structure having a top cover, a front element, a back element and a side panel depending from one side edge of the top cover, said structure being so hinged to said top member that the edge of the top cover opposite from said one side edge lies adjacent one edge of said top member in one angular position of said structure; means carried by said rig for raising and lowering said firebox; power operated means carried by said frame and attached to said rig for moving the rig; a rigid bar removably pivoted at one end to said frame and at its other end to said extension structure intermediate its axis of rotation and its side panel, said bar acting to rotate said extension structure selectively to and from its operating position in response to lateral movement of said rig; and a removable side for the firebox to close the otherwise open side of the firebox when the extension side structure is not being used.

4. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; means for supporting the other end of said frame on an axle carried between two Wheels; a rig movably depending from said frame for lateral movement; a firebox disposed beneath said rigand at least indirectly supported thereby,

said firebox having an open bottom and comprising a top member, a front wall, a back wall and at least one elongated angularly movable side extension structure having a top cover, a front element, a back element and a side panel depending from one side edge of the top cover, at least one of said walls having a plurality of openings therein and at least one of said elements having an aperture therein, said structure being so hinged to said top member that the edge of the top cover opposite from said one side edge lies adjacent one edge of said top member in one angular position of said structure; means carried by said rig for raising and lowering said firebox; a rigid bar reinovably pivoted at one endto said frame and. at its other end to said extension structure intermediate its tion; means carried by said rig for raising and lowering said firebox; and a removable plate for closing the otherwise open side of the firebox when said extension side structure is rotated to an inoperative position.

axis of rotation and its side panel, said bar acting to rotate said extension structure selectively to and from its operating position in response to lateral movement of said rig; a removable side for the firebox, to close the otherwise open side of the firebox when the extension side structure is not being used; a plurality" of air-and-fuelsupplied nozzles, each aligned with one of said openings for producing flames inside said. firebox; an air-supply pipe; and an additional air-and-fuel-supplied nozzle so supported thereby, said firebox having an open bottom and comprising a top member, a front wall, a back wall and at least one. elongated angularly movable side extension structure having a top cover, a front element, a back element and a side panel depending from one side edge of thetop cover, said structure being so hinged to the top member of the firebox that the structures top cover becomeseifectively an extension of said top member when said structure is in an operative angular posi- 6. In a mobile surface heater, a combination includ ing: a general horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; means for movably supporting the other end of said frame; a rig movably depending from said frame for lateral movement, a firebox disposed beneath said rig and at least indirectly supported thereby, said firebox having an open bottom and comprising a top member, a front wall, a back wall and'a pair of elongated angularly movable side extension structures each having a top cover, a front element, a back element and a side panel depending from one side edge of the top cover, each of said structures being so hinged to the top member of said firebox that the structures top cover becomes effectively a continuation of said top member when said structure is in an operative angular position; means carried by said rig for raising and lowering said firebox; and a pair of plates each removably attachable to the firebox for closing an otherwise open side thereof when the extension structure hinged above said open side is rotated to an inoperative position above the firebox.

7. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; means for movably supporting the other end of said frame; a firebox at least indirectly supported by said frame, said firebox having an open bottom and comprising a top member, a front wall, a back wall and at least one elongated angularly movable side extension structure having a top cover, a front element, a back element and a side panel depending from one side edge of the top cover, said struc ture being so hinged to the top member of the firebox that the structures top cover becomes effectively an extension of said top member when said structure is in an operative angular position; means at least indirectly supported by said frame for raising and lowering said firebox; and a removable plate for closing the otherwise open side of the firebox when said extension structure is rotated to an inoperative position.

8. In a mobile surface heater, a combination including: a generally horizontal suspension frame; means for attaching one end of said frame to a towing vehicle; mobile means for supporting the other end of said frame; a firebox at least indirectly supported by said frame, said firebox having an open bottom and comprising a top member, a front wall, a back wall and a pair of elongated angularly movable side extension structures each having a top cover, a front element, a back element and a side panel depending from one side edge of the top cover, each of said structures being so hinged to the top member of the firebox that the structurestop cover becomes effectively a continuation of said top member when said structure is in an operative angular position; means at least indirectly supported by same frame for raising and lowering said firebox; and a pair of plates each removably attachable to the firebox for closing an otherwise open side thereof when the extension structure hinged above said open side is rotated to an inoperative position above the firebox.

9(The combination of claim 5 with the addition of means for limiting the angular movement of said extension structure when it is rotated to an inoperative position over said firebox.

. 10. The combination of claim 6 with the addition of means for limiting the angular movement of said extension structures when they are rotatedto their inoperative positions over said firebox.

l1. Thecombination of claim 7 with the addition of means for limiting the angular movement of said extension structure when it is rotated to an inoperative position'o'ver said firebox. v

8 12. The combination of claim 8 with the addition of means for limiting the angular movement of said extension struotures when they are rotated to their inoperative positions over said firebox.

References Cited by the Examiner UNITED STATES PATENTS 582,420 5/97 Hancock 126-2712 18 McKeen et a1. 126-2712 Ward 126-271.2 Williams et a1 126271.2 X

Sowell 126271.2

FOREIGN PATENTS 11/48 Australia.

1/47 Great Britain.

875,817 1/08 Howard 126271.2 10 JAMES W. WESTHAVER, Primary Examiner.

Claims

7. IN A MOBILE SURFACE HEATER, A COMBINATION INCLUDING: A GENERALLY HORIZONTAL SUSPENSION FRAME; MEANS FOR ATTACHING ONE END OF SAID FRAME TO A TOWING VEHICLE; MEANS FOR MOVABLY SUPPORTING THE OTHER END OF SAID FRAME; A FIREBOX AT LEAST INDIRECTLY SUPPORTED BY SAID FRAME, SAID FIREBOX HAVING AN OPEN BOTTOM AND COMPRISING A TOP MEMBER, A FRONT WALL, A BACK WALL AND AT LEAST ONE ELONGATED ANGULARLY MOVABLE SIDE EXTENSION STRUCTURE HAVING A TOP COVER, A FRONT ELEMENT, A BACK ELEMENT AND A SIDE PANEL DEPENDING FROM ONE SIDE EDGE OF THE TOP COVER, SAID STRUCTURE BEING SO HINGED TO THE TOP MEMBER OF THE FIREBOX THAT THE STRUCTURE''S TOP COVER BECOMES EFFECTIVELY AN EXTENSION OF SAID TOP MEMBER WHEN SAID STRUCTURE IS IN AN OPERATIVE ANGULAR POSITION; MEANS AT LEAST INDIRECTLY SUPPORTED BY SAID FRAME FOR RAISING AND LOWERING SAID FIREBOX; AND A REMOVABLE PLATE FOR CLOSING THE OTHERWISE OPEN SIDE OF THE FIREBOX WHEN SAID EXTENSION STRUCTURE IS ROTATED TO AN INOPERATIVE POSITION.