Patent GB-946541-A (GB)
Title: Improvements in or relating to the spraying of marking substances on to roads and other surfaces
Inventor: BARKER ALFRED WALTER
IPC: E01C23/22
Filed: 1959-06-11
Abstract: 946,541. Line-markers for roads &c. SANDALL PRECISION CO. Ltd. June 9, 1960 [June 11, 1959; Nov. 10, 1959], Nos. 19988/59 and 19431/60. Divided out of 38110/59. Heading A6D. [Also in Division B2] A vehicle for marking lines on roads &c. of the kind in which a liquid is sprayed by one or more guns fed with liquid from a reservoir by compressed air provided by a motor driven compressor, the spray being confined between lateral shields or stencil wheels, is adapted for the spraying of thermoplastic substances and, accordingly, the reservoir is enclosed in a bath containing heating liquid of a sufficient temperature to maintain the substance in a sprayable condition; the conduit feeding the guns from the reservoir is jacketed to allow heating liquid to be circulated through the bath and throughout the jacketing means to the guns. Two laterally spaced spray guns 4, Figs. 4, 14 and 15, are carried by a transversely extending manifold 60 at the front of a self propelled vehicle, Fig. 1, and each gun is located between two stencil discs 154 each heated by a gas burner ring 163 enclosed within a metal shroud 169. The discs are supported on stub shafts 155 carried in arms 156 pivoted on a horizontal shaft 157, and the stub shafts are axially adjustable and held in the desired position by ball catches to provide the required distance between the discs. Two scrapers 170 on arms 171 pivoted at 172 are located between each pair of discs and are urged into contact with them by a compression spring 173, Fig. 14. Each gun emits a fan shaped spray, and the width of the line is adjusted by varying the height of the guns and the disc spacing. The manifold 60, Fig. 9, to which each gun is attached; consists of an inner conduit 62 for the marking liquid and an outer conduit 61 for the heating liquid, and the marking liquid flows to the central bore 17 of each gun and is sprayed from a passage 41 when a needle 43 is retracted. Retraction of the needle and spraying takes place when compressed air is fed to an inlet 58 whereby a piston 51 carrying the needle is moved upwardly against a spring 56. The gun outlet is thus opened, and compressed air is allowed to flow from outlet 59 to an inlet 25 and then from an annular space 19 through ducts 38 to a chamber 37. From the latter the air flows through circumferentially spaced passages about a member 34 and surrounding the liquid passage 41. Heating liquid is fed to the annular space 18 from the manifold and passes from an outlet 24 back to the heating bath. The part 44 of the needle cleans the outlet 41. The reservoir 5, Figs. 4 and 5, for the marking liquid is enclosed in a heat insulated oil bath 6 heated by a gas burner 76 supplied with gas from a cylinder 11 under the control of an electric solenoid operated valve which may be thermostatically controlled so that the spray liquid is heated to a desired temperature. A pilot burner and a blower for the main burner are provided. A safety device comprising a bursting disc 68 on a tube 69 allows, in the event of an explosion, spray liquid to pass from the reservoir through a hood 71 by which it is directed downwardly on to the ground. Hot spray liquid is fed to the manifold 60 by an extension of the inner conduit 62 connected to the reservoir and surrounded by an outer jacket through which hot oil is circulated by a pump 97, Fig. 4. Oil from the jacket is passed to the manifold by a pipe 95 and after flowing through the various conduits and guns is returned to the bath by a pipe 98. Compressed air for operating the guns, and for subjecting the reservoir to pressure for feeding the spray liquid to the guns, is provided by a compressor 9, Fig. 4, driven by an engine 10, which supplies a cylinder 8. Before being supplied to the guns the compressed air is fed through pressure regulators 112, 113 and then through lines 103, 104 to pipes 105, 106, Fig. 5, coiled around the reservoir 5 so that the air is heated. The air is then passed separately to the guns via lines under the control of electric solenoid operated valves 117, 118 which may be operated independently so as to provide different line markings. The opening and closing of these valves is effected automatically according to predetermined cycles by opening and closing the circuts to the solenoids; this may be effected by rotary cams associated with switches, preferably driven from a road engaging wheel, so that the spray operation is related to the vehicle speed. As described, a rotary shaft 121, Fig. 17, carries a cylinder 128 having spaced therealong a number of cams 129 to any one of which a micro-switch 130, controlling the circuit feeding the solenoids, may be aligned. The switch is movable along a bar 132 and is locked in a desired position so that its operating button 131<SP>1</SP> coacts with the desired cam surface. A separate micro-switch may be provided for each valve 117, 118. The shaft 121 is driven through sprockets and chains by a ground engaging wheel 123, Fig. 16, carried by an arm 124 pivoted to the vehicle chassis and urged downwards by a spring 125. The electrical system is supplied from batteries charged by a dynamo driven by the engine 10. Instead of the valves 117, 118 being operated electrically from selector cams they may be directly operated mechanically by such cams. The manifold 60 is adjusted vertically by a rotary shaft 146 having a hand wheel and being screw threaded at its lower part for engaging a thread on a part attached to the manifold; it is locked in position by a nut 153. In order to remove dust from the road prior to its being marked, one or more fan-tailed preferably adjustable nozzles 176, Fig. 4, are located in front of the guns, and are fed either with compressed air or with exhaust gases from the engine 10. A suction fan 182 within an open ended tubular casing withdraws smoke or fums from the vicinity of the guns.