US3373938A - Boom directed spray marking devices - Google Patents

Description

March 19, 1968 H. c. SWEET BOOM DIRECTED SPRAY MARKING DEVICES 5 Sheets-Sheet 1 Filed March 7, 1966 INVENTOR HAROLD 6. SWEET /fi evi M, 4

A TORNEYS H. c. SWEET 3,373,938

BOOM DIRECTED SPRAY MARKING DEVICES 5 Sheets-Sheet 2 arch 19, 1968 Filed March 7, 1966 FIGB I'Ul l m f FIG. 2

' INVENTOR HAROLD C. SWEET BY MM, Aim g ATTORNEYS March 19, 1968 H. c. SWEET ,9

BOOM DIRECTED SPRAY MARKING DEVICES Filed March 7, 1966 5 Sheets-Sheet 3 i: FIG-6 INVENTOR HAROLD c. SWEET ATTORNEYS United States Patent 3,373,938 DOOM DIRECTED SPRAY MARKING DEVICES Harold C. Sweet, New Hudson, Mich., assignor to H. C. Sweet Co., Inc., New Hudson, Mich., a corporation of Michigan Filed Mar. 7, 1966, Ser. No. 532,231 18 Claims. (Cl. 239-148) ABSTRACT OF THE DISCLOSURE The present invention relates to manually propelled spray equipment and more particularly to a wheeled device for applying a marking fluid in a continuous line on either vertical or horizontal surfaces.

Many vehicles have heretofore been provided wherein a reservoir of marking fluid is supported on a wheeled carrier having handle means for manual propulsion. Usually a spray gun or nozzle is adjustably fixed to the carrier and a source of compressed air delivers the marking fluid to the nozzle and assists in discharging an atomized mixture of fluid and air.

Line marking vehicles of this type are used to mark trafiic lines at intersections, to mark the lines defining the car spaces in a parking lot, to mark the playing lines on an athetic field and the like. In order for the user to propel the vehicle to mark a straight line, conventional line marking vehicles are provided with non-swiveling wheels. A disadvantage in a vehicle of this conventional types lies in the weight of the device that has to be manipulated between the discontinuities in the line. In addition to the paint reservoir, an engine driving an air compressor and the associated tank and other accessories are carried on the vehicle bed so that the overall weight of the device can total 200-300 pounds. In order for the user to reverse the direction of the vehicle to assume a new position prior to laying a new line, he has to raise the vehicle so that one or more wheels disengage the ground, and then pivot the vehicle around the remaining wheels. This is very strenuous work for a user laying out several hundred non-contiguous line such as in a parking lot. In addition it has been found that the time to go from the end of one marked line to the beginning of the next is greater than the line marking time.

Furthermore conventional line marking devices discharge the marking fluid through a nozzle provided with masks or spaced plates that direct the discharging fluid to deposit to a desired width of line on the surface to be' marked. The nozzle in this conventional type of device is mounted on the vehicle at an adjustable spacing from the ground and adapted so that the user has to bend down to manipulate the masks. Another version of the type of device is characterized by a nozzle which discharges a conical spray and is held in a vertically adjustable cup which may be positioned at the necessary spacing from the ground to achieve the desired width of line. In either of the aforementioned devices, once the nozzle is positioned at the necessary spacing from the surface to be marked, the vehicle then must be manipulated so that 3,373,938 Patented Mar. 19, 1968 ice the nozzle is positioned directly over the path of the line which is to be laid.

A conventional heavy vehicle is difficult and strenuous to manipulate for the aforementioned reasons.

Another characteristic of conventional line marking vehicles is the utilization of a tank to contain the marking fluid which is pressurized by compressed air to assist delivering the marking fluid to the discharge nozzle. In order to contain a suitable quantity of marking fluid to avoid constant refilling, such tanks usually have a capacity of from 2 to 7 gallons. Pressure tanks of this size normally have to comply with local safety codes regarding pressure vessels. Tanks built to the specifications required by such codes are normally of a heavy and expensive construction. But of even greater importance, the covers of such tanks are usually timev consuming to remove in order to refill the container. The pressurized air supply must first be sealed from the tank, then a number of hold-down wing nuts removed in order to detach the cover. Fluid is then poured in the tank and the cover replaced.

The present invention as embodied in a line-marking vehicle obviates the above problems in addition to providing a number of special advantages over conventional line marking devices. A preferred line-marking vehicle comprises a wheeled platform or truck having a handle and supporting an internal combustion engine driving connected to an air compressor having output to an air tank. The truck preferably is provided with a pair of non-pivotable spaced wheels supportingly connected to the forward end of the platform, and a single, pivotable wheel supportingly connected to the rear end of the truck. The pivotable wheel allows a user to easily and quickly maneuver the vehicle into any desired position and facing the desired direction. It further allows the user to propel the vehicle in a curved or irregular line of travel. In order to assist the driver in propelling the vehicle in a straight line, the pivotable wheel is rotatingly mounted between a pair of caster side lates pivotably connected to the truck platform. The side plates carry a rearward extending bracket supporting a locking pin. A slotted flange slidably connected to the platform and having a foot controlled handle is operable to engage the pivotable wheel locking pin so that the wheel is rigidly and directionally aligned with the front wheels. With the locking pin engaged, the vehicle can easily be propelled in a straight line.

A major feature of the improved line marking device comprises an upright support member fixed to one side of the truck which carries a movably mounted sleeve. One end of an elongated tubular boom member is telescopically carried by the sleeve and is both longitudinally and rotatably movable within the sleeve.

A cup adapted to receive a fluid discharge nozzle fluidly connected to a fluid supply tank is pivotably mounted about a transverse axis and adjacent the extending end of the boom. Handle means are provided adjacent the truck handle that are adapted to enable the user to pivot the sleeve carrying boom in vertical and horizontal planes so that the nozzle carrying end of the boom may easily be moved laterally with respect to the truck and at any desired elevation. Handle means are also provided adjacent the truck handle that enable the user to pivotably move the nozzle with respect to the boom.

The purpose of the boom directed nozzle is to enable the user to quickly position the vehicle in a proximate position near the surface to be marked. He then can move the nozzle over the path defiining the line to be marked. In the case of a horizontal surface, a scale is provided on the flywheel shield of the air compressor. A finger carried by the movable sleeve enables the user to determine when the boom has positioned the discharge nozzle to the necessary height to produce the desired width of line. By rotating the boom, the nozzle can be directed at the vertical or inclined surface of curbing, car parking bumpers, guard rail faces, etc., a feature not provided in conventional line marking devices. An elevated horizontal surface such as the crown of a curb may be quickly marked by swinging the boom over the curb, another feature not provided for in conventional line markers. The telescopically mounted boom enables the discharge nozzle to be positioned forwardly of the truck when marking smooth surfaces or rearwardly to the front wheel axles to minimize variable spacing of the nozzle with respect to the ground caused by an irregular or bumpy surface.

The discharge nozzle is preferably connected by flexible hoses to a fluid supply tank and may therefore be readily removed from the retainer cup for manual marking of an irregular shaped object such as the base of a lightpost or sign. This feature eliminates the necessity for the user to carry an auxiliary hand gun or brush for the purpose.

To reduce the time consuming task of filling a pressurized container with marking fluid, a dual tank system is provided in the preferred line-marker. A small supply tank, preferably having a capacity of approximately one gallon and adapted to be pressurized by the air tank, is seated on the truck plateform. A larger storage tank is supported by the truck platform at a higher elevation than the supply tank. The storage tank, preferably of about seven gallon capacity, is provided with a removable splash cover. A conduit having a normally closed valve fluidly connects the two tanks. The pressurized supply tank delivers marking fluid to the discharge nozzle.

The storage tank is normally filled by removing the splash cover and pouring in fresh marking fluid. The storage tank contains the marking fluid at atmospheric pressure; therefore it can be inexpensively constructed.

The supply tank is refilled from the storage tank by opening the inter-tank valve to permit marking fluid to transfer by gravity flow. It has been found that by leaving the fluid connection between the air tank and the supply tank open during the refilling process, that pressurized air will flow through the inter-tank conduit, in a counter-direction to the flowing marking fluid, into the storage tank to create a turbulence in the marking fluid. This turbulence functions to agitate the fluid and insure the homogenuity of the fluid as it flows downwardly.

It is therefore an object of the present invention to provide a wheeled line-marking vehicle adapted to lay straight or irregularly shaped lines by providing such a vehicle having non-pivotable wheels and a pivotable wheel and a foot operated locking mechanism adapted to engage the pivotable wheel in directional alignment with the nonpivotable wheels for making straight lines and to disengage the pivotable wheel for making irregular or curved lines.

It is another object of the present invention to improve the versatility of line-marking vehicles by providing such a vehicle with a boom directed fluid discharge nozzle, the boom having means for positioning the nozzle to discharge marking fluid against horizontal, inclined, vertical or raised surfaces.

It is still another object of the present invention to decrease the time required in positioning a line-marking vehicle by providing a vehicle of the type which need be maneuvered in only a proximate position relative to the path defiining the line to be marked, and a transversely movable boom extending from said vehicle which carries a fluid discharge nozzle.

Other objects and advantages of the present invention will be more readily apparent from the following detailed description of a preferred embodiment thereof. The description makes reference to the drawings in which:

FIG. 1 is a perspective elevational view illustrating a preferred embodiment of the present invention;

FIG. 2 is an enlarged view as seen from line 2-2 of FIG. 1 with the boom pivoted to a horizontal position;

FIG. 3 is an enlarged view as seen from line 3-3 of FIG. 2;

FIG. 4 is an enlarged view as seen from line 4-4 of FIG. 1, and with parts cut away for purposes of clarity;

FIG. 5 is a schematic view of the preferred markingfluid flow system;

FIG. 6 is a plan view of the rear wheel locking mechanism and FIG. 7 is a sectional view of the locking mechanism as seen from line 7--7 of FIG. 6-.

Now referring to the drawings, FIG. 1 illustrates a preferred line-marking device generally comprising a truck 10 carrying a compressed air system 12, a marking-fluid supply system 14, a boom member 16 movably mounted to the truck 10 and a nozzle spraying assembly generally indicated at 18.

The truck 10 comprises a pair of metal tubular arms 20 and 22 fixed at opposite sides of a rectangular metal platform 24. The arms extend upwardly from the platform 24 and then converge together at their upper ends as indicated at 26, A substantially horizontal handle 28 is welded to the upper end of the arms 20 and 22, and is provided with handle grips 30.

The platform 24 is mounted on a pair of fixed spaced apart non-pivotable wheels 32 supportably mounted under the forward end of the platform 24 and a third wheel 34 supportably mounted to a housing 36 pivotably connected to the rear underside of the platform 24,

Referring to FIGS. 6 and 7, a rearwardly extending bracket 38 is fixed to the housing 36 and carries a vertically mounted pin 40. The platform 24 has a transversely connected angle member 42 which carries a pair of parallel, spaced flat guide plates 44 on the underside thereof. Each of the guide plates 44 is provided on their underside with an extending retainer plate 46 positioned to define a seat for a pin engaging plate 48 which is forwardly and rearwardly slidable therein.

A foot actuated handle 50 is pivotably connected to the underside of one of the guide plates 44 and also pivotably connected to the rear end of the slidable plate 48 by nut and bolt 52. The handle 50' has a slot 51 which permits the bolt 52 to move longitudinally of the handle 50 when a force is applied to the end thereof so that the plate 48 can be moved forwardly or rearwardly.

The forward end of the plate 48 has an intermediate slot 54 with diverging sides as at 56. When the handle 50 is operated to move the plate 48 to its forward position, the slot 54 engages the pin 40 to rigidly lock the wheel housing 36 in directional alignment with the non-pivotable forward wheels 32. The diverging sides 56 assist the plate 48 in urging the pin 40 into the slot 54 so that the user need not precisely align the pin 46 with the slot 54 before moving the handle 50 forward.

It can be seen that when the pivotable wheel housing 36 is locked in position, that the vehicle will move in a straight path when propelled forward. When the housing 36 is disengaged, the vehicle can be propelled in a curved or any irregular path. It is obvious that the plate 48 could be provided with a plurality of slots adapted to engage and lock the wheel 34 at an angular alignment with the fixed forward wheels 32 so that the vehicle could be propelled in a regularly curved path.

As can be seen in FIGS. 1, 2 and 3, platform 24 has a vertically extending support member 56 fixed to one side thereof and rearwardly of forward wheels 32. The support 56 has a vertical sleeve 58 which is preferably welded to and extends above the upper end of support 56. The sleeve 58 rotatingly carries a right angle pin 59 which extends through the top of the sleeve 58 to carry a pivot plate 60 extending inwardly of the support 56.

A bracket 62 carried by arm 22 and extending inwardly thereof pivotably carries a threaded nut 64. An angular handle member 66 having a horizontal, elongated, threaded portion 68 is movably journalled in the nut 64 and has an end journaled in an eye 70 pivotably carried by the free end of the pivot plate 60. Rotation of the handle '66 pivots the plate 60 and the pin 59. The lower end of the pin 59 pivotably carries an outwardly extending sleeve 72 which on the underside thereof carries an elongated sleeve 74 at a right angle relationshlp.

The boom 16 is preferably formed of an elongated c rcular tubing and is rotatably and slidably journaled 1n the sleeve 74. The boom 16 has a forwardly extending end 76. A cross bar 78 fixed adjacent the rearward end of the boom 16 provides a handle for rotational or longitudinal movement of the boom 16 within the sleeve 74. To clamp the boom 16 with respect to the sleeve 74, a conventional locking knob 79 is carried by the sleeve 74 and is adapted to lockingly engage the boom 16.

A bracket 80 extends outwardly from the arm 22 and carries a vertical, internally threaded sleeve 82 above and spaced from the sleeve 74. A threaded adjusting member 84 having an angular handle 86 and carried by the sleeve 82 extends therethrough and downwardly to contact a pivot plate 88 fixed to the sleeve 74 and sleeve 72. The weight of the projecting portion of the boom 16 normally urges the plate 88 upwardly against the threaded member 84. It can therefore be seen that vertical and lateral adjustment of the boom end 76 may be accomplished by rotation of handles 86 and 66 respectively.

Now referring to FIG. 4, the boom end 76 carries a pivotably connected right angle member 90 having an outwardly extending foot 92. The :member 90 preferably is pivotable about an axis lying in a plane normal to the longitudinal axis of the boom 16. A tubular nozzle retainer 94 is fixed to and extends through the foot 92. The lower end of the nozzle retainer 94 is preferably threaded to carry a short tubular extending shield 98. The plate 90 has a rearwardly extending lug 100 which pivotably carries one end of a push rod 102. The push rod 102 extends rearwardly of lug 100 and is journaled in a short tubular section 104 having a locking thumb screw (not shown) and which is pivotably mounted to the bracket 80. The push rod terminates adjacent the handle 28 and carries a knob 106. By moving the push rod 102 forwardly or rearwardly, the nozzle retainer 94 can be pivoted with respect to the boom end 76.

The nozzle spraying assembly 18 comprises a conventional fluid discharge nozzle 108 having a compressed air inlet 110 and a marking fluid inlet 112. The inlet 110 has a manual valve assembly 114 adapted to actuate the nozzle 108 to discharge a conical pattern of air and marking fluid. The nozzle retainer 94 is adapted to retain the nozzle 108 so that the discharge orifice is directed through the shield 98.

It can therefore be seen that when the nozzle 108 is seated in the retainer 94, it can be spaced vertically from the wheel supporting surface by rotation of handle 86, it can be moved transversely of the longitudinal axis of the vehicle by rotation of handle 66, it can be moved longitudinally with respect to the wheel base by telescoping the boom 16 within the sleeve 74, and it can be rotated to an angular position with respect to the wheel supporting surface by rotating the boom 16 within the sleeve 74 and by pivotal movement of the retainer 94 actuated by the push rod 102.

Now referring to FIG. 1, the compressed air system preferably comprises an interal combustion engine 118 drivingly connected to an air compressor 120 having output to an air tank 122. As can be seen schematically in FIG. 5, the air tank 122 delivers compressed air through a flexible conduit 124 to the nozzle 108. A manually operated pressure regulator 126 is disposed at the outlet of the tank 122 and is operative to allow air to pass through the conduit 124.

Still referring to FIG. 5, the marking fluid supply system 14 comprises the supply tank 116 seated on the platform 24 and a storage tank 128 having a removable splash cover 130 and supported by a frame 132 on the platform 24 but at an elevation higher than the tank 116. The

storage tank 128 preferably has a fluid Capacity of five to seven gallons. The supply tank 116 is fluidly conne t to the storage tank by a conduit 133 having a nor l y closed valve 134. The conduit 133is adapted so that when valve 134 is open, fluid can transfer by gravity flow from the storage tank 128 to the supply tank 116, but when th valve 134 is closed, there is no fluid communication between the two tanks.

A conduit 136 connected to the compressed air conduit 124 and to the supply tank 116 permits compressed air to pressurize the tank 116. A pressure regulator 138 is dispose-d in the conduit 136 and is operable to regulate the pressure in tank 116. When the tank 116 is pressurized, fluid is available for delivery to the nozzle 108 through a flexible conduit 140. A shut off valve 142 is disposed in the conduit 140.

In operation, the marking fluid supply system 16 functions as follows: The storage tank lid is opened to permit fluid to be poured into the tank 128 and the lid 130 reseated. The tank 128 is normally at atmospheric pressure.

The supply tank 116 is refilled opening valve 134 to permit fluid to flow from the storage tank 128. Conduit 133 is chosen of a suitable diameter so that bubbles of air from tank 116 surge upwardly to storage tank 128 and create a turbulence or agitation in the fluid. This agitation assists in mixing the fluid during the refilling step.

A push rod 143 having a free end adjacent handle 28 is movably fixed to arm 20 and operatively connected to a valve 144 disposed in the compressed air conduit 124 intermediate valve 114 and conduit 136. When the nozzle 108 is seated in the retainer 94, valve 114 is normally open and the user introduces air to the nozzle 108 by opening valve 144. The compressed air then aspirates the marking fluid from the tank 116 to form a conical discharge. The flexible conduits are of a suitable length so that the user can remove the nozzle 108 from the retainer 94 to mark a raised vertical or irregular surface. In this mode of operation, the valve 144 is normally open and the amount of air admitted to the nozzle 108 controlled by manipulating valve 114.

Referring to FIG. 1, the flexible conduits and 124 also permit the user to deposit the nozzle 108 in a cupshaped container 146 mounted on the platform 24 and containing a solvent when the vehicle is not being operated.

It is obvious that as the conical fluid discharge from the nozzle 108 is spaced higher or lower from the wheel supporting surface, the line laid thereon increases or decreases in width.

To assist the user in spacing the nozzle 108 with respect to the Wheel bearing surface in order to obtain the proper width of line, the air compressor 120 has a belt guard 148 on which is marked a scale 150 indicating lnches of line width. As can best be seen in FIG. 3, the boom carrying sleeve 74 has a finger member 152 adapted to move adjacent the scale 150 as the nozzle 108 is raised or lowered.

Referring to FIG. 4, an elongated guide member 154 IS slidably carried by the truck 10 adjacent the bottom mounted side and has a retracted position and an extended position to assist the user in propelling the line-marking truck 10 along a predetermined irregular or regular path.

It will be seen that the same type of structure as disclosed herein can be easily adapted to provide parallel lines by mounting a second boom on the opposite side of the vehicle.

It will be understood that although I have described a preferred line marking vehicle having a wheel locking mechanism adapted to engage a pivotable rear wheel, it will be obvious to one skilled in the art that a foot operated locking mechanism could be readily mounted on a vehicle having non-pivotable rear wheels and a pivotable forward wheel. A pivotable wheel supportably mounted forwardly or rearwardly assists the user in manipulating the vehicle and a locking mechanism for engaging the pivotable wheel assists in propel-ling the vehicle in a straight path.

It is to be further understood that although I have described a fluid discharge nozzle which utilizes pressurized air to aspirate the marking fluid, it is obvious that a discharge nozzle having only a fluid supply conduit and wherein the supply tank 116 is sufficiently pressurized to 'deliver the fluid to the discharge nozzle could be readily utilized.

It will be apparent to those skilled in the art to which the invention pertains, that various modifications and changes may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A paint spraying device useful in marking straight and curved lines on horizontal surfaces and in marking horizontal and vertical faces of curbs and the like, said paint spraying device comprising:

(a) a supporting platform;

(b) non-pivotal wheel means supporting the forward portion of said platform;

() pivotal wheel means supporting the rearward portion of said platform;

((1) locking means carried by said platform for locking said pivotal wheel means against pivotal movement so that the application of a propelling force on said platform drives said platform along a predetermined path, said pivotal wheel means and nonpivotal Wheel means cooperating to guide said platform along a variable path when said locking means are in a non-locking condition;

(e) an upright support mounted on said platform;

(f) a boom;

(g) means mounting said boom to said upright support for movement about horizontal and vertical axes so that the forward end of said boom can be positioned in a selected attitude relative to the path of said supporting platform;

(h) a spray nozzle;

(i) nozzle mounting means mounting said spray nozzle on said boom and forward of said upright support, said nozzle mounting means being rotatable about an axis substantially perpendicular to the longitudinal axis of said boom so that said nozzle can be positioned to accommodate the attitude of said boom; and

(j) a self-contained source of pressurized marking fluid connected to said nozzle so that said nozzle produces a marking stripe as said platform is propelled along a path.

2. A spray device as defined in claim 1, wherein said locking means includes means directionally align said pivotal wheel means with said non-pivota1 wheel means so that when a driving force is applied to said platform, said wheel means cooperate in guiding said wheeled platform in a straight line.

3. A spray device as defined in claim 1, wherein said nozzle is adapted to discharge a conically shaped pattern of fluid, and including means for selectively spacing the discharge end of said nozzle from a horizontal surface.

4. A spray device as defined in claim 1, wherein said nozzle is adapted to discharge a conically shaped pattern of fluid.

5. The paint striping apparatus as defined in claim 1, wherein said wheel-locking means are foot-operated.

6. A paint spraying device as defined in claim 1, wherein said boom mounting means comprises a sleeve mounted on said upright support, said boom being telescopically carried by said sleeve and including means for clamping said boom to said sleeve so that said nozzle can be swung in a selected arc.

7. A paint spraying device as defined in claim 6, wherein said sleeve is rotatably mounted on a substantially horizontally supported pin so that said nozzle can be raised and lowered to a selected height.

8. A paint spraying device as defined in claim 6, wherein said sleeve is rotatably carried by a substantially vertically mounted pin so that said nozzle can be moved in lateral directions toward and away from the path of movement of said platform.

9. A spray device as defined in claim 6 including a first handle means operable to pivot said sleeve around a vertical axis and a second handle means operable to pivot said sleeve around a horizontal axis.

10. A spray device as defined in claim 6 and including means mounting said boom about its longitudinal axis and rotatably in said sleeve.

11. A paint spraying device, comprising:

(a) a platform;

(b) wheel means for supporting said platform for movement;

(c) handle means mounted on said platform so that an operator can push said platform along a path;

(d) a self-contained source of pressurized paint mounted on said platform;

(e) locking means on said platform for engaging said wheel means so that the application of a propelling force on said handle means drives said platform along a predetermined path;

(f) a boom;

(g) means mounting said boom on said platform so that the operator can swing the forward end of said boom between raised and lowered positions and between lateral positions relative to said platform;

(h) a nozzle adapted to discharge paint in a spray;

(i) flexible conduit means connecting said self-contained source of pressurized paint to said nozzle for the delivery of paint to said nozzle; and

(j) means for mounting said nozzle and said flexible conduit means to the end of said boom for rotation about an axis generally perpendicular to the longitudinal axis of said boom so that the paint can be discharged from said nozzle in a selected lateral direction relative to said boom.

12. A spray device as defined in claim 11, wherein the paint discharge end of said nozzle may be selectively spaced from a vertical surface.

13. A spray device as defined in claim 11, wherein said boom mounting means includes (a) a vertical support member fixed to one side of said platform; and

(b) means for mounting said boom adjacent the upper end of said vertical support member so that said boom pivots about a point vertically displaced above said platform.

14. A spray device as defined in claim 11, wherein said self-contained source of pressurized paint includes:

(a) a lower container for containing paint mounted on said platform;

(b) an upper container having a paint storage capacity greater than said lower container and mounted on said platform above said lower container;

(0) conduit means providing a connection between said upper container and said lower container;

(d) valve means in said conduit means having an open condition to permit the transfer of paint from said upper container to said lower container by gravity flow in order to replenish said lower container, and a condition to seal said upper container from said lower container; and

(e) means providing a connection between said lower container and said nozzle for the transfer of paint to said nozzle from said lower container when said valve means are in their closed condition.

said pressurized air to pressurize said lower container when said valve means are in their closed condition and second means for delivering said pressurized air to said nozzle to aspirate paint from said lower container.

16. A spray device as defined in claim 15, wherein said source of pressurized air includes (a) an air compressor mounted on said truck, and

(b) power means drivingly connected to said air compressor.

17. The combination of:

(a) a spray nozzle;

(b) aframe;

(c) a lower container mounted on said frame and adapted to contain a marking liquid under pressure;

(d) first conduit means connecting said nozzle to said lower container for the transfer of marking liquid from said lower container;

(e) first air delivery means for introducing pressurized air into said container during the transfer of marking liquid from said lower container to said nozzle in order to assist the transfer of said marking liquid;

(f) an upper container mounted on said frame above said lower container; said upper container adapted to hold a greater quantity of marking liquid than said lower container;

(g) second conduit means providing a connection between said upper container and said lower container for the transfer of marking liquid by gravity flow;

(h) valve means in said second conduit means for closing communication between said lower container and said upper container in order to pressurize said lower container for the transfer of marking liquid from said lower container to said nozzle, said valve means being opened to allow the transfer of a replenishment quantity of marking liquid from said upper container 'to said lower container; and

(i) second air delivery means for delivering said pressurized air to said nozzle to aspirate marking liquid from said lower container.

18. The combination as defined in claim 17, wherein said upper container is adapted to receive and contain said marking liquid at atmospheric pressure.

References Cited UNITED STATES PATENTS 2,618,576 11/1952 Brown et al. 239-148 X 2,857,201 10/1958 Palmer 239-281 2,903,082 9/1959 Marcus.

2,964,245 12/1960 Anderson et al. 239-150 3,007,645 11/1961 Little 239-150 3,061,201 10/1962 Rienecker 239-281 3,074,649 1/1'963 Atkinson 239- 3,140,050 7/1964 Elmore 239-148 X M. HENSON WOOD, JR., Primary Examiner.

V. C. WILKS, Assistant Examiner.

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