Material spreader system

A material spreader system is designed to dispense a topping material through a widthwise slot onto the surface of a plastic substance such as concrete lying within an area having a length, width, and opposing sides. The material spreader system includes a spreader for storing a supply of topping material and for dispensing a layer of the topping material as the spreader is translated along a path. A drive system is coupled to the spreader to translate the spreader across the path formed by the bridge to thereby dispense a layer of topping material over the entire area. Sequential translations of the spreader across the bridge followed by sequential translations of the bridge along the length of the area covers the entire surface of the area with a layer of topping material.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to material spreading systems, and more 
particularly, to systems which include a spreader that is translated above 
the surface of a plastic material which cannot support the spreader. 
2. Description of the Prior Art 
The prior art includes a variety of different types of material spreaders. 
U.S. Pat. No. 2,806,435 (Mundell) discloses a suspended refuse spreader 
which includes a hopper translatable along the length of a pair of fixed, 
overhead rails. The hopper of this spreader hangs below these fixed suport 
rails and includes a plow-like deflector which deflects the refuse into 
two spaced apart piles as the spreader is translated along the rails. A 
cable is attached to one end of the spreader to translate the spreader 
with respect to the support rails. 
U.S. Pat. No. 2,807,234 (Middlen) discloses an engine-driven livestock 
feeding apparatus which can be translated along a pair of fixed rails 
between which a livestock feed trough is positioned. The material 
discharged from the lower portion of this apparatus is separated by a 
deflector within the trough into two heaps so that cattle on both sides of 
the rail system can be fed. 
U.S. Pat. No. 1,200,393 (Neller) discloses an overhead carrier which is 
translated along a single fixed overhead rail. When the carrier reaches 
the desired unloading position, the hopper of the carrier is tilted 
sideways to discharge the contents. 
U.S. Pat. No. 3,230,845 (Mauldin) discloses a spreader which rolls over and 
is supported by the surface upon which material is to be spread. U.S. Pat. 
No. 3,453,988 (Trent) discloses a portable spreader which is linearly 
translatable along the length of of a pair of fixed rails. 
U.S. Pat. No. 2,113,503 (Belkesley) discloses a multiple-purpose spreader 
which includes a hopper supported by a grouping of three wheels. This 
topping spreader rolls over the area upon which material is to be 
discharged. 
U.S. Pat. No. 2,318,064 (Delaney) discloses a conventional fertilizer 
spreader which includes a hopper and a finger agitator rotated by the 
spreader wheels. A mechanically actuated gate is positioned in the lower 
portion of the hopper and meters the discharge of material from the 
spreader. 
A wide variety of other types of relevant prior art has been cited in each 
of the related patent applications indentified above in the section 
entitled "Field of the Invention." 
SUMMARY OF THE INVENTION 
Briefly stated, and in accord with one embodiment of the invention, a 
material spreader system dispenses a topping material onto the surface of 
a plastic substance lying within an area having a length, width and 
opposing sides. The area may include a vertically extending obstruction 
positioned adjacent one of the sides of the are and extending a 
predetermined distance into the area. The presence of the obstruction 
within the area defines a reduced width section of the area. The material 
spreader system includes a spreader having a hopper for storing a supply 
of topping material and for dispensing a layer of the topping material as 
the spreader is translated along a path. Bridge means having first and 
second ends provides an elevated path to permit widthwise translation of 
the spreader across the area. Means is coupled to the hopper for metering 
the discharge of topping material from a widthwise slot in the hopper at a 
range proportional to the translation velocity of the spreader and 
independent of the vertical spacing between the spreader and the plastic 
surface. The metering means includes means for agitating the topping 
material within the hopper. In one embodiment of the invention, the 
spreader includes a hydraulic pump for providing a source of pressurized 
hydraulic fluid and means for energizing the pump. A first hydraulic motor 
translates the spreader back and forth across the bridge means. Various 
other hydraulic motors, valves and other elements may be provided to 
operate or control various others features of the invention. In another 
embodiment of the invention, the bridge means may include means for 
varying the length of the bridge means to enable the bridge means to clear 
the obstruction as said bridge means is translated past the reduced width 
section of the area. In addition the bridge means may include means for 
varying the vertical separation between the bridge means and the surface 
of the plastic substance.

DETAILED DESCRIPTION OF THE INVENTION 
In order to better illustrate the advantages of the invention and its 
contributions to the art, the various mechanical features of the preferred 
embodiment of the invention will now be reviewed in detail. 
Referring now to FIG. 1, a multi-section, variable length bridge 10 
includes parallel bridge spans 12 and 14. Guide means including linear, 
vertically oriented guide rails 16 and 18 are positioned as shown on the 
innermost sections of spans 12 and 14 and define a linear path along each 
bridge span. First and second bridge support units are coupled to spaced 
apart end sections of bridge 10 and each include a roller unit have a pair 
of spaced apart wheels 20 which are of a fully castering design to 
facilitate movement and positioning of bridge 10 along the load supporting 
perimeter of an area of non-load bearing plastic concrete 22. Bridge 10 is 
fabricated in sections generally five to ten feet long. A short single 
section bridge length is illustrated in FIG. 2, but multiple bridge 
sections can be readily coupled together to form an overall bridge length 
of sixty-five feet or longer. Wheels 20 of the first and second roller 
units of bridge 10 are supported either on solid ground, a solid, 
previously cured concrete surface, or any other firm, non-yielding surface 
that forms a perimeter outside the plastic concrete surface area 22. 
Referring now generally to FIG. 1-5, spreader 24 includes four wheels 26 
with rubber pneumatic tires which serve as spreader to bridge coupling 
means. Wheels 26 are rotatably coupled to spreader 24 by axles 28 and 30 
and serve to transfer the weight of spreader 24 to bridge 10. Spreader 24 
includes a hopper 32 having first and second side surfaces 34 and 36 and 
first and second end surfaces 38 and 40. End surfaces 38 and 40 are 
inclined with respect to the vertical axis of spreader 24 and the lower 
ends of these end surfaces converge to form a widthwise slot 42. 
As illustrated in FIG. 1, spreader to bridge coupling means in the form of 
first and second spaced apart wheel assemblies each including at last one 
rolling member in the form of a wheel 26 engage guide rails 16 and 18 at 
first and second spaced apart intervals along the length of bridge 10. 
Because guide rails 16 and 18 define parallel, linear paths along the 
length of bridge 10 and because the left and right sets of spreader wheels 
26 are configured to engage the vertically oriented surfaces of guide 
rails 16 and 18, the spreader to bridge coupling means or wheels 26 
function to direct spreader 24 along the straight line path as the 
spreader is translated back and forth along bridge 10. Although prior art 
two wheel spreaders freely rotate about their two axially aligned wheels, 
the spreader to bridge coupling means of the preaent invention includes 
first and second wheel assemblies which engage bridge 10 at first and 
second spaced apart intervals along the length of the bridge span to 
maintain a fixed planar relationship between spreader 24 and the bridge. 
This feature of the invention thereby maintains a fixed planar 
relationship between spreader 24 and the concrete surface 22 to provide a 
highly stable platform for distributing topping material from widthwise 
slot 42. 
Referring now also to FIGS. 6A and 6B, a gate 44 includes clam shell doors 
46 and 48. The linkage which actuates clam shell doors 46 and 48 will be 
discussed in detail by referring to FIGS. 5, 6A and 6B. Rods 50 and 52 
extend through the lower sidewalls 34 and 36 of spreader 24. Rods 50 and 
52 are freely rotatable with respect to sidewalls 34 and 36. A group of 
four standoffs 58 are rigidly mounted to end surfaces 38 and 40 of hopper 
32. Rods 50 and 52 are freely rotatable with respect to standoffs 58. On 
each side of spreader 24, a gate actuator arm 60 is rigidly coupled to rod 
50 and extends vertically upward. Rotational displacement of arm 60 causes 
rod 50 to rotate and thereby rotationally displaces linkage elements 62, 
64, 66, 68 70, 72 and 74 and is illustrated in FIGS. 6A and 6B. Clam shell 
doors 46 and 48 are rotatably coupled to sidewalls 34 and 36 of spreader 
24 by rods 76 and 78. Reinforcing elements 80 and 82 are coupled to the 
lower surfaces of clam shell gates 46 and 48 to provide additional 
strength and rigidity. 
A flange 84 extends horizonatally outward from the upper side surfaces of 
spreader 24 and an actuator arm 60 extends vertically upward through slot 
86 in flange 84. Actuator arm 60 is in a vertical position when gate 44 is 
closed over slot 42. In this closed position, actuator arm 60 contacts and 
is stopped by the end of slot 86. A clamp can be positioned at a 
predetermined distance along the length of slot 86 in an arrangement which 
prevents further movement of actuator arm 60 along the length of slot 86. 
Clamps can thus be applied to flanges 84 to limit the maximum open 
position of gate 44. FIG. 3 best illustrates the manner in which pneumatic 
actuator 88 includes a cylinder which is secured to the side of spreader 
24. An actuator arm of actuator 88 is coupled to gate actuator arm 60. 
Referring now to FIGS. 2 and 5, a 1.3 horsepower, sixty PSI high torque 
pneumatic motor 90 is coupled to end member 38 of hopper 32 by a mounting 
bracket 92 and serves as rotary drive means for rotating wheel axle 28 and 
paired wheels 26 of one wheel assembly. Motor 90 is commercially available 
from the Gast Manufactured Company of Benton Harbor, Mich. (model number 
4AM-RV-75-GR20) Sprocket wheels on the output drive shaft of motor 90 and 
on wheel axle 28 provide a ten to one gear reduction and are coupled 
together by a drive chain 94. An additional bearing block 96 is coupled to 
the inner surface of the housing of spreader 24 to more rigidly support 
axle 28 in the vicinity of motor 90. Motor 90 can be operated in either a 
forward or a reverse direction depending on whether pressurized air is 
coupled to port 98 or port 100. 
A plurality of three pneumatic air vibrators 102 is coupled to end member 
40 of hopper 32 as is best illustrated in FIG. 5. When pressurized air is 
supplied to the input ports of each of these air vibrators, a weighted 
piston within the cylinder of each device vibrates up and down along the 
vertical axis of the device. This piston reciprocates at a rate of ten 
thousand cycles per minute. Pneumatic air vibrators of this type are 
commercially available from the Navco Manufacturing Company. Note that 
each of these vibrators is positioned near the lowermost portion of hopper 
32 and that these vibrators are separated by a uniform spacing along the 
width of hopper 32. Air vibrators 102 commence operation when actuator 88 
is operated to open gate 44. The vibrations produced by air vibrators 102 
causes the topping material within hopper 32 to be uniformly metered from 
gate 44 and prevents undesired particle build-ups in hopper 32. 
Referring now to FIGS. 4 and 5, a chain 104 surrounds a pair of sprocket 
wheels which are coupled to the drive shaft of finger agitator or rotating 
metering means 106 and to wheel axle 8. As depicted in FIGS. 2 and 4, 
finger agitator 106 includes a plurality of radially extending vanes 
coupled to a generally horizontally oriented shaft. A chain guard 105 is 
positioned around chain 104 and serves as a protective device. Since 
wheels 26 are rigidly coupled to axle 28, the linear translation of 
spreader 24 along bridge 10 rotates wheels 26 adn rotates finger agitator 
106 at a rate directly proportional to the rate of translation of spreader 
24. Faster movement of spreader 24 causes more rapid rotation of finger 
agitator 106 and a more rapid rate of discharge of topping material from 
gate 44 when it is in the open or partially open position. Thus, a uniform 
topping discharge density is provided which is not affected by the rate of 
translation of spreader 24. 
Referring now to FIGS. 1-3, a pair of support arms 108 extend vertically 
upward from the midsection of bridge 10. A pair of coiled, flexible double 
passageway air hoses 110 and 112 extend from support arms 108 to support 
arms 114 and 116 on spreader 24. Double passageway air hoses 110 and 112 
are routed through support arms 108 to a control station 118 on bridge 10 
which serves as drive control means for controlling the direction of 
movement of spreader 24 along bridge 10 and for energizing and 
deenergizing rotating metering means or finger agitator 106. A source of 
pressurized air (about 60 PSI, 25 C.F.M.) is coupled to control station 
118. 
The pressurized air coupled to support arm 116 operates actuator 88 and 
pneumatic vibrators 102. The pressurized air supplied to spreader 24 
through support arm 114 is coupled to input ports 98 and 100 of motor 90. 
One of the two flow control valves in control station 118 controls the air 
pressure directed to actuator 88 and air vibrators 102 while the second 
control valve regulates the amount and direction of air coupled to motor 
90. This second control valve permits motor 90 to be operated in either 
forward or reverse directions to regulate the direction of travel of 
spreader 24. Varying the amount or air pressure transmitted to motor 90 
can vary the velocity of spreader 24 from a low translation speed of about 
twenty feet per minute to a high translation speed of about one hundred 
feet per minute. 
The manner of operating and using the concrete topping spreader of the 
present invention will now be described in some detail. Generally, a three 
man crew is required to operate the topping spreader in the most efficient 
manner. One crew member is primarily responsible for reloading the hopper 
with the desired topping material. One man operates the control station to 
regulate the direction and speed of operation of the spreader across 
bridge 10. The third man assists in laterally translating bridge 10 along 
a length of a section of concrete over which the topping material is to be 
distributed. Many different topping materials such as quartz, mineral, 
metallic, traprock, and emery can be accurately dispensed by the present 
system. 
The desired rate of distribution of topping material is first determined 
and a clamp or other similar device is positioned along slot 86 of flanges 
84. This determines the maximum open position of clam shell gate 44. With 
typically used topping material, the rate of distribution can be varied 
from about one tenth of a pound of topping material per square foot to 
about four pounds per square foot. After the hopper of spreader 24 has 
been loaded, the operator opens both control valves at control station 
118. Actuator 88 is thereby actuated to the open position and motor 90 
commences rotation. Rotation of motor 90 causes axle 28 to rotate which 
rotates chain 104 and thus finger agitator 106. The extreme outer edges of 
finger agitator 106 are positioned within about one eighth of an inch of 
side surfaces 38 and 40 of hopper 32 and serve to wipe away any topping 
material which may have formed an obstruction or bridge and, in addition, 
insures a free and uniform flow of topping material through clam shell 
gate 44 at all times. Air vibrators 102 commence operation when actuator 
88 causes gate 44 to open. 
After spreader 24 has completely traversed the widthwise span of bridge 10 
across concrete surface 22, the spreader is stopped, the bridge is 
laterally translated a distance equal to the width of topping material 
previously spread and the spreader is translated over the bridge 10 in the 
opposite direction. This procedure is repeated with intervening reloading 
steps until the complete surface of the wet concrete has received a layer 
of topping. 
Referring now to FIGS. 7-12, a modified version of the concrete topping 
spreader will now be described in detail. This modified spreader 
embodiment illustrated in FIGS. 7-12 will be referred to as spreader 124. 
As was the case with bridge 10 depicted in FIG. 1, the multi-section, 
variable length bridge 10 depicted in FIG. 7 incorporates triangular truss 
bridge spans 12 and 14 each having a load bearing base, the upper surface 
of which supports wheels 26 of spreader 24. Each bridge span terminates in 
an end section and includes an apex element which in the illustrated 
embodiment of the invention is positioned below and centered about the 
span base. The apex element is oriented parallel to the span base. A 
plurality of spaced apart struts extend between the first and second 
spaced apart edges of the span base and the apex element to thereby define 
the sides of the triangular truss bridge span. The triangular truss 
configuration of bridge spans 12 and 14 can be fabricated in five foot and 
ten foot sections as described above and assembled in the field into a 
desired length of up to at least sixty-five feet as dictated by the width 
of the area of plastic concrete 22. FIG. 7 specifically indicates the 
manner in which dual air hoses 110 and 112 are coupled between bridge 10 
and spreader 124. On each side of bridge 10, a pair of outriggers 126 and 
128 extend laterally outward and are coupled together by a tightly 
stretched support cable 130. FIG. 10 specifically indicates that a 
plurality of laterally translatable guideblocks 132 are coupled at evenly 
spaced apart intervals to air hose 110. A clamp 134 is coupled to the 
lower portion of guideblock 132 and includes a pair of cylindrical 
apertures through which each individual air hose of the dual air hose 
assembly 110 can be routed. The free end of air hose 110 is coupled to 
spreader 124 by support 116. The guideblocks are laterally translated back 
and forth across bridge 10. Air hose 112 is coupled to bridge 10 in a 
similar manner. 
Both air hoses 110 and 112 are coupled to a control panel 118. FIGS. 7 and 
12 indicate that an air input hose 136 is coupled to master on/off valve 
138. Pneumatic valve 150 is coupled to control assembly 118 and air hose 
112 and serves as a motor throttle valve. Actuating valve 150 to provide 
pressurized air to one of the two hoses of hose assembly 112 causes motor 
90 to rotate in a forward direction. Controlling the rate of air flow 
through valve 150 varies the operating speed of motor 90. When pressurized 
air is coupled by valve 150 to the second air hose of air hose assembly 
112, motor 90 rotates in a reverse direction at a rate controlled by the 
amount of air flow provided. 
Control valve 152 in control unit 118 actuates air vibrators 102 and the 
two pneumatically controlled gate position control cylinders 140. In the 
first position, valve 152 directs pressurized air through one of the two 
air hoses in hose assembly 110, causing the shafts of the two air actuator 
cylinders 140 to be retracted into the position illustrated in FIG. 9. As 
indicated in FIG. 9, shaft 142 and pneumatic actuator 140 are coupled to 
gate 144 which pivots about shaft 146 into an open position which 
establishes a gap indicated by reference number 148 between side surface 
or first end wall 40 and the smoothly curved cylindrical section which 
forms the upper surface of gate 144. When control valve 152 is moved into 
the "off" position, air pressure is removed from the hose which supplies 
air under pressure to air vibrators 102 and is routed instead to the 
second air pressure port of actuator cylinders 140. In the "off" position 
valve 152 directs pressurized air through the second hose of air hose 
assembly 110 which actuates pneumatic actuator 140 and causes shafts 142 
to extend. Extension of shafts 142 rotates gate 144 into the "closed" 
position and terminates the flow of material through widthwise slot 42 of 
spreader 124. In FIG. 9, the dotted lines indicate the "closed" position 
of gate 144. 
Referring now to FIGS. 9 and 11, an adjustable mechanical stop 153 limits 
the maximum gate displacement into the "open" position to thereby control 
the rate at which topping is dispensed as spreader 124 is laterally 
translated. In the preferred embodiment of the present invention, a one 
inch diameter threaded rod 154 passes through an aperture cut in the lower 
end wall of the base of spreader 124. A nut 155 is welded to the exterior 
surface of the base of spreader 124 and causes rotation of rod 154 to 
displace the end of rod 154 fore and aft with respect to the side of gate 
144. A second bolt is welded to the exterior end of rod 154 to permit stop 
153 to be readily adjustable by means of a wrench. A hollow tubular 
support bracket 156 is welded to the interior side surface of the base of 
spreader 124. Bracket 156 both supports and guides rod 154 and serves to 
maintain rod 154 in a fixed vertical position with respect to gate 144. 
In order to simplify the drawings, only a portion of stop 153 is 
illustrated in FIG. 9 and only one of the two stops actually used in the 
preferred embodiment of the present invention is illustrated in FIG. 11. 
It should be understood that a second stop is provided on the opposite 
side of the base of spreader 124 so that the one stop abuts each end of 
gate 144. Generally it will be desireable to either weld a flat plate to 
gate 144 at the point at which the end of stop 153 will strike the gate or 
alternatively to form a notch on the end sections of gate 144 so that each 
end of stop 153 will strike a surface substantially perpendicular to the 
end of rod 154. 
It is generally desirable to fabricate the inclined end walls 38 and 40 of 
the spreader at an angle approaching 45.degree.. The vibrations produced 
by air vibrators 102 cause end wall 40 to form a vibrating feeding surface 
which prevents the topping material contained within the hopper from 
adhering to this vibrating surface and insures that the topping will flow 
downward along end surface 40 smoothly and evenly through the gap 148 
formed in widthwise slot 42. Finger agitator 106 also assists in providing 
a uniform flow of topping through gap 148 by maintaining the topping 
material in a fluffed or agitated state. This fluffing action provided by 
finger agitator 106 prevents compaction of the topping material which in 
many circumstanced would cause an uneven and irregular flow of topping 
material. 
The unique structure of the upper surface of gate 144 which is formed in 
the shape of a section of the wall of a cylinder produces a sliding 
contact with the lower surfaces of end walls 38 and 40. This unique 
structure provides a self-cleaning feature of the gate which prevents 
topping material from adhering to the linear right hand lip surface of 
gate 144 which defines one side of gap 148. As gate 144 is snapped into 
the closed position by actuator cylinders 140, the scraping action between 
the lower edge of end wall 40 and the curved upper lip surface of gate 144 
removes all topping from the gate lip. 
Stop 153 must be adjusted to the desired setting before the spreading 
operation is commenced. For many standard types of topping material, the 
two stops are adjusted so that 1/8" gap is established at gap 148 when 
gate 144 is in the open position. The dimension of gap 148 must always be 
greater than the diameter of the material to be spread. 
Continuously maintaining the self-cleaning lip of gate 144 in a clean 
condition, the ability to precisely control the dimension of gap 148, the 
continuous vibration of end wall 40, and the constant translation velocity 
of spreader 124 enables the present invention to uniformly spread topping 
material with a distribution accuracy of two to three percent which has 
previously been unobtainable by any prior art device or technique. 
The method of operation of the present invention will now be discussed in 
detail. First, the hopper is filled with the desired topping material. 
Motor throttle valve 150 is actuated to propel spreader 124 in the desired 
direction and at the desired velocity. As the spreader passes above the 
beginning of the wet concrete surface, control valve 152 is actuated, 
causing actuator cylinders 140 to snap gate 144 into the desired open 
position which is determined by stops 153 which have been previously 
adjusted. In a typical application, stops 153 will be adjusted to provide 
a 1/8" gap 148. Under normal operation, a single pass of spreader 128 
across bridge 10 will distribute topping at the rate of 1/4 pound per 
square foot. If an application of one pound per square foot is desired, 
spreader 124 must make four sequential passes over the same area of wet 
concrete. The topping is thus distributed in four separate blankets which 
has been found to produce far superior results than can be attained by a 
single higher topping distribution rate pass. At the end of the fourth 
pass, bridge 10 is laterally translated so that spreader 124 can then be 
translated across the next section of wet concrete four more times. To 
produce an application rate of 11/2 pounds per square foot, six passes of 
spreader 124 over the wet concrete would be provided. 
It will be apparent to those skilled in the art that the concrete spreader 
system disclosed above may be modified in numerous ways and may assume 
many embodiments other than the preferred forms specifically set out and 
described above. For example, a separate wheel could be coupled to the 
shaft of finger agitator 106 in a manner which would permit it to contact 
the surface of spans 16 and 18 of bridge 10. In this embodiment, finger 
agitator 106 rotates at a rate proportional to the spreader translation 
velocity. Additionally, the spreader may be powered by a gas, electric or 
hydraulic motor and controlled by a computer or by remote control means 
receiving radio or optical control signals. Numerous other structural and 
operational modifications would be readily apparent to one skilled in the 
art. The concrete topping spreader system of the present invention can be 
used to spread various types of topping materials over many different 
types of surfaces and does not require an elevated bridge of the specific 
type disclosed. 
Referring now to FIGS. 13-21, a significantly improved and more 
sophisticated material spreader system is disclosed. This improved 
spreader system is designed to dispense a topping material onto the 
surface of a plastic material such as uncured concrete which is lying 
within an area having a length, width and opposing sides. At many job 
sites, the area of plastic material may include a vertically extending 
obstruction such as a column which penetrates a predetermined distance 
into the side of the area. Great difficulty has been encountered in 
efficiently and economically dispensing a topping material over an area 
which includes a number of vertical obstructions of this type. When using 
material spreaders of the type disclosed in FIGS. 1-12 above, awkward and 
difficult techniques such as skewing the bridge deck to spread topping 
material over plastic concrete lying between a pair of spaced apart 
columns has proven to be less than satisfactory. Significant amounts of 
additional time and effort are required to utilize these techniques and to 
then reposition the spreader/bridge assembly on the opposite side of these 
vertical obstructions. When vertical obstructions are present on a job 
site, job completion times and labor expenses are drastically reduced by 
utilizing the material spreader system illustrated in FIGS. 13-21. 
Referring initially to FIGS. 13-16, one embodiment of a material spreader 
system adapted to dispense a topping material over an area including a 
vertical obstruction will now be described in detail. 
As is readily apparent from FIG. 16, material spreader 200 is substantially 
similar in design to material spreader 124 described above and illustrated 
in FIGS. 7-9 and 11. In FIG. 16, the elements of material spreader 200 
have been designated with reference numbers corresponding to reference 
numbers utilized in connection with the description above of material 
spreader 124. Material spreader 200 has been provided with a hopper cover 
202 which includes an open rectangular grate or screen which assists in 
separating or breaking up the topping material as the topping material is 
loaded into the hopper of material spreader 200. In addition, material 
spreader 200 has been provided with a set of four flanged wheels 204 which 
couple material spreader 200 to bridge means 206 which is illustrated in 
FIG. 13. A square tube agitator 208 may be substituted for finger agitator 
106 if particularly large size topping material is to be dispensed from 
the spreader. 
FIGS. 13 and 14 illustrate that air hoses 110 and 112 are coupled to take 
up reels 210 and 212 which are spring biased to minimize slack in the air 
hoses coupling reels 210 and 212 to spreader 200 as spreader 200 is 
translated from one end of bridge 206 to the opposite end and back. FIG. 
14 illustrates the manner in which spreader 200 is energized and 
controlled and corresponds to the structure depicted and described in 
connection with FIG. 12. 
Referring now to FIGS. 13, 15, and 18-20, the adjustable bridge means 206 
of the present invention will be described in detail. Bridge 206 includes 
first and second spaced apart spans 214 and 216 which engage the four 
flanged wheels 204 of spreader 200 and provide and elevated path to permit 
widthwise translation and spreader 200 across an area of plastic concrete 
or other surface over which topping material is to be dispensed. 
FIGS. 13 and 20 illustrate that control valves 150 and 152 are positioned 
within a control station 218 which is rotatably coupled to the lower end 
section of span 216. A locking pin 220 maintains control station 218 in a 
normal or "extended" position depicted in the left side of FIG. 20 or in 
the "retracted" or obstruction clearance position depicted in dotted lines 
in the right side of FIG. 20. Control valves 150 and 152 are operative 
when control station 218 is in either the extended or retracted position. 
Referring now to FIGS. 13, 15, 18 and 19, the span length reducing means of 
bridge 206 will now be described in detail. Each end of spans 214 and 216 
of bridge 206 includes pivotable gate sections 222 and 224, each of which 
includes a vertically extending stop 226 which prevents spreader 200 from 
being translated beyond either end of bridge 206. Each side of gate 
sections 224 and 226 includes a three-element hinge 228 and a removable 
hinge pin 229 which couples the gate sections to the bridge spans. (See 
FIG. 18) FIG. 19 illustrates that the outer hinge pin has been removed 
from gate section 224, permitting that gate section to be swung in a 
clockwise direction into an inboard retracted position shown. Removal of 
hinge pin 229 from hinge 228 on the opposite side of gate section 224 
permits counterclockwise rotation of that gate section over clamp 232 into 
an outboard retracted position. Gate section 222 includes identical double 
hinge structure and can also be pivoted into either an inboard or outboard 
retracted position. 
The vertical dimension of gate sections 222 and 224 is less than the 
vertical dimension of bridge spans 214 and 216 to provide clearance 
between these gate sections and other structural elements of the spreader 
system. An auxiliary stop 230 is bolted to the hinged junction between the 
gate sections and the bridge spans when the gate sections are in the 
retracted position illustrated in FIG. 19 since stop 226 will have been 
laterally displaced from the path of wheels 204 and will no longer provide 
the required stopping feature to prevent inadvertent damage to the 
equipment. 
The material spreader system of the present invention also includes 
translatable bridge support means which is best illustrated in FIGS. 13, 
15, 18 and 19. A clamp 232 is coupled to the lower end section of both 
ends of bridge spans 214 and 216 and receives each of a pair of wheels 234 
and wheel mounting brackets 236. Each end of bridge 206 includes a pair of 
clamps 232, wheels 234 and wheel brackets 236 which are collectively 
referred to as a first support means or a first roller assembly. A first 
roller assembly supports each of the two ends of bridge means 206 and 
permits the bridge to be translated along the length of the area over 
which topping material is to be dispensed. Wheels 234 are fully castering 
pneumatic tire and wheel assemblies of the type described in connection 
with the spreader depicted in FIG. 7. 
The translatable bridge support means of the present invention further 
includes second means for supporting an end of bridge means 206 as the 
bridge means is translated along a reduced width section of the area over 
which topping material is to be dispensed. In the preferred embodiment of 
the present invention, this second support means includes a second roller 
assembly which is coupled to each end of spans 214 and 216 of bridge 206. 
Each element of the second roller assembly includes a small wheel 238, a 
vertically oriented screw jack assembly 240 which is coupled to tubular 
clamp 232, and a jack handle. Screw jack assembly 240 is actuated to 
elevate wheel 238 above the surface of the plastic concrete over which the 
material spreader system is translated to permit the first roller assembly 
to support the bridge as the material spreader system is being laterally 
translated across the full width section of the area of plastic concrete. 
Referring now to FIG. 21, roller support means 244 includes a clamp 
assembly 246 which is coupled around and securely attached to a vertically 
oriented obstruction in the form of a column 248. Clamp 246 is fabricated 
from rectangular plates 254, threaded rods 260 and wingnuts 262. A 
horizontally oriented channel shaped track 250 is coupled to and supported 
by clamp assembly 246. Clamp assembly 246 includes telescopic adjustment 
structure which permits the lateral spacing between track 250 and column 
248 to be varied as desired so that track 250 can readily engage wheels 
238 of the second roller assembly. This telescopic adjustment structure 
comprises hollow rectangular tubes 256 to which slide tubes 258 are 
coupled. The set bolts located in the top of tubes 256 lock slide tubes 
258 in the desired position with respect to column 248. Alternatively, 
structure may be provided to telescopically or otherwise adjust either the 
length of spans 214 and 216 or the relative lateral position of screw jack 
assembly 240 with respect to spans 214 and 216. The telescopic adjustment 
feature accommodates either differences in the lateral spacing between 
pairs of spaced apart columns 248 at a particular job site or accommodates 
different lateral spacings encountered at various different job sites. 
The manner in which the material spreader system is utilized to spread a 
uniform layer of topping material over an are including full width and 
reduced width sections of the type described above will now be described 
in detail primarily by reference to FIGS. 13 and 17A-D. FIG. 13 and FIG. 
17A depict the configuration of the material spreader system which is 
typically utilized to support the material spreader in an elevated 
position above an area of plastic concrete. Wheel mounting brackets 236 
are coupled to bridge spans 214 and 216 and extend outward a length 
sufficient to permit wheels 234 to contact an underlying supporting 
surface 252 adjacent to, but outside of the area of, plastic concrete. 
Wheels 238 are elevated above the surface of plastic concrete so that the 
entire bridge assembly is supported by and laterally translated by wheels 
234. When a vertical obstruction such as column 248 is approached, clamp 
assembly 246 together with track 250 is coupled to the column such that 
the lowest part of the entire clamp/track assembly is elevated at least 
slightly above the upper surface of the plastic concrete surface. 
As column 248 is approached, the spreader is moved away from the end of 
bridge 206, hinge pin 229 is removed and gate section 224 is rotated into 
the retracted position illustrated in FIG. 19. Auxiliary stop 230 is 
bolted into place and the entire bridge assembly is translated closer 
toward column 248. FIG. 17B illustrates that the bridge assembly is then 
translated toward column 248 so that screw jack assembly 240 can be 
actuated to cause wheel 238 to engage track 250 and thereby elevate wheel 
234 above surface 252 which had previously supported the weight of bridge 
span 216. Once the weight of span 216 is properly supported by track 250, 
the securing means of clamp 232 are loosened and the assembly comprising 
wheel 234 and wheel mounting bracket 236 is completely removed from span 
216 as is depicted FIG. 17C. 
Depending on the relative positioning of columns 248, the operation 
depicted in FIGS. 17A-17C will take place either sequentially at one end 
of the bridge followed by the other end of the bridge, or will take place 
simultaneously when the columns are in paired, spaced apart alignment. In 
situations where only one side of the area to which topping material is to 
be applied includes vertically oriented obstructions, the procedures 
depicted in FIG. 17 will be accomplished for only a single end of bridge 
206. 
When the configuration depicted in FIG. 17C has been achieved, the bridge 
will be translated further along the length of the area of the plastic 
concrete until the spreader is properly aligned to dispense an additional 
layer of topping material. Bridge 206 can be translated back and forth 
along the entire length of track 250 as required. When bridge 206 is 
translated into the position illustrated in FIG. 17D, the assembly 
consisting of wheel 234 and wheel mounting bracket 236 is reinserted into 
claim 232 and properly adjusted and secured. Jack screw assembly 240 is 
then actuated to transfer the weight from wheel 238 back to wheel 234. As 
bridge 206 is translated further along the length of plastic concrete, the 
procedure described immediately above is repeated to support the same end 
of span 214 above the concrete surface. Typically, with a track of the 
length and configuration depicted in FIG. 17, only a single span of bridge 
206 will be supported by the clamp assembly/track at one time. 
Although only a single embodiment of the improved material spreader system 
has been described, it would be readily apparent to one of ordinary skill 
in the art to produce a wide variety of structural modifications to this 
invention which would be equivalent to the invention described above. For 
example, a clamp assembly could be coupled to column 248 at a point above 
the spans of bridge 206 and could be engaged by a second support assembly 
extending upward from the bridge. In another embodiment, translatable 
bridge support means in the form of a ceiling mounted crane could be 
coupled by a grouping of cables to bridge 206. When a vertical obstruction 
such as a column is approached as the ceiling mounted crane is translated 
along the length of the area of plastic concrete, the adjustable bridge 
means could be actuated to reduce the length of the bridge spans, 
permitting translation of spreader 200 over the reduced width section of 
the area of plastic concrete. Another readily apparent modification of the 
present invention involves substituting rollers for wheels 234 to permit 
the bridge means to be translated along and supported by the forms 
surrounding the area of plastic concrete. 
The bridge disclosed in connection with the preferred embodiment of the 
present invention could also take many different forms other than the 
specific embodiment described above. Rather than having the pivotable gate 
sections which permit the span length of the bridge to be increased and 
decreased as desired, removable end sections, telescopic adjustment 
features for various other elements of the bridge spans or numerous other 
types of length adjustment devices could be incorporated into a bridge 
assembly and still fall within the scope of the present invention. 
Furthermore, a bridge assembly for supporting a translatable spreader may 
take the form of a single rail and the spreader could coupled above, below 
or on both sides of that rail. 
While the material spreader system has been described in connection with 
dispensing topping material onto a plastic concrete surface, this same 
invention could be used without modification to dispense a topping 
material onto a built up roof or onto any other surface which requires a 
topping or coating material but which cannot permit the wheels of a 
conventional spreader to contact the surface to be coated with topping 
material. Referring now to FIGS. 22-30, yet another embodiment of the 
material spreader system of the present invention will be described in 
detail. This spreader system includes a spreader having a totally 
self-contained hydraulic system. In addition, the bridge of this 
embodiment of the material spreader system includes structure for readily 
adjusting the vertical spacing between the bridge and the surface of the 
plastic substance. The bridge also includes telescopically adjustable end 
sections for providing continuous adjustment of the overall bridge length. 
Referring initially to FIGS. 22-25, one embodiment of a hydraulically 
powered material spreader system adapted to dispense a topping material 
over an area including a vertical obstruction is disclosed. 
A material spreader 300 includes a material hopper 302 for storing a supply 
of topping material. A removeable hopper grate 304 includes a screen-like 
sieve for breaking clumps of topping material as the material is dispensed 
from a bag or other container into hopper 302. A bag cutting blade 306 may 
be secured as shown to grate 304 to assist in tearing open a bag of 
topping material. 
The inclined sides of hopper 302 converge at the lower section of the 
hopper to form a widthwise slot of the type disclosed in detail in FIGS. 8 
and 9. A gate 308 is fabricated from a cylindercal section and can be 
displaced between first and second positions to alternately cover and 
uncover the widthwise slot of the hopper. FIG. 24 illustrates that a 
hydraulic cylinder 310 is coupled to an actuator arm 312 of gate 308. A 
threaded coupling in actuator arm 312 permits adjustment of the "open" 
position gate 308 to vary the rate of material dispensed from the hopper 
302 as spreader 300 is translated back and forth across the bridge. 
Spreader 300 includes a first pair of flange wheels 314 and a second pair 
of flanged wheels 315 which engage first and second spaced apart tracks or 
spans 316 and 318 of bridge 320. 
Flanged wheels 324 are rigidly coupled together by a drive shaft 322 which 
is rotatably coupled to spreader 300 by a pair of spaced apart bearing 
assemblies, such as bearing assembly 324. Flanged wheels 325 are coupled 
together by second rigid shaft 326 which also serves as a finger agitator. 
Driven shaft/finger agitator 326 passes through the lower interior section 
of hopper 302 and serves to rigidly couple together the pair of spaced 
apart flanged wheels 315 and to act as a finger agitator to fluff up the 
particulate topping material stored within hopper 302. 
Referring now also to FIG. 25, energizing means such as a five horsepower 
gasoline engine 328 includes an output shaft 330 which is coupled to 
operate a vane double section hydraulic pump 332 of the type manufatured 
by the Sperry-Vickers Company. Pump 332 comprises part of an open loop 
hydraulic system and produces two independent pressurized fluid outputs 
designated by reference numbers 334 and 336. A hydraulic reservoir 338 
serves as a source of hydraulic fluid which is used by the spreader 
hydraulic system. In FIG. 25, standard schematic diagram symbols have been 
utilized to show the specific configuration and coupling of each hydraulic 
component part of the hydraulic system of spreader 300. A throttle cable 
340 permits the operating RPM of engine 328 to be controlled from a 
readily accessible location. 
The particulate contents of hopper 302 are vibrated by an eccentrically 
weighted vibrating element taking the form of a shaft 342 to which a 
plurality of spaced apart, eccentric weights 344 are rigidly secured as 
depicted in FIG. 23. The output shaft of a small hydraulic motor 346 is 
directly coupled to shaft 342. The entire vibration generating mechanism 
is coupled to the interior inclined hopper sidewall at a location 
analogous to the location of the vibration generating elements depicted in 
FIG. 8. FIG. 25 illustrates that output 336 of hydraulic pump 332 is 
coupled to a pressure relief valve 348, to a flow control valve 350, and 
to on/off valve 352. Flow control valve 350 can be adjusted to regulate 
the operating speed of hydraulic motor 346 to thereby control the 
intensity and frequency of the vibration imparted to the contents of 
hopper 302. Valve 352 either activates or deactivates hydraulic motor 346 
to energize or deenergize the hopper vibrating system. 
The second output 354 of hydraulic pump 332 is coupled to a pressure relief 
valve 334 and to an on/off valve 356. Valve 356 is actuated by actuator 
arm 358 (see FIG. 23) which can be conveniently reached by an operator 
standing at either side of spreader 300. When engine 328 is operating, 
displacement of valve 356 into the "on" position provides pressurized 
hydraulic fluid to hydraulic cylinder 310 for opening gate 308. Actuation 
of valve 356 into the "on" position also transmits pressurized hydraulic 
fluid through flow control valve 360 and forward/reverse valve 362 to 
motor 364. Motor 364 is coupled by a pair of sprockets and a drive chain 
designated by reference number 366 to rotate drive shaft 322. 
Referring now to FIGS. 22, 23 and 25, sensing means is provided to sense 
the arrival of spreader 300 at a predetermined location along bridge 320 
and to generate a reversing signal at that time. Reversing means is 
coupled to the sensing means and to hydraulic motor 364 for reversing the 
flow of hydraulic fluid through motor 364 in response to the reversing 
signal. The sensing means includes a reversing bracket 364 which is 
coupled to bridge 320 to permit engagement by reversing bracket engaging 
means in the form of a forked actuator arm 370. An overcenter locking 
device 372 includes a biasing spring 374 which maintain actuator arm 370 
in either a first or second position until actuator arm 370 is displaced 
in to the opposite position by engaging a reversing bracket 368. The two 
arms of actuator arm assembly 370 are laterally offset along actuator arm 
shaft 376 so that actuator arm 370 will be engaged by only one specific 
reversing bracket 368. Typically a first reversing bracket 368 is coupled 
in proximity to one end of bridge 320, while a second reversing bracket 
368 is coupled in proximity to the opposite end of bridge 320. The arms of 
these two reversing brackets 368 are laterally offset to engage a specific 
arm of forked actuator arm 370. 
As illustrated in FIG. 25, the shaft 376 of actuator arm 370 is coupled to 
a pilot valve 378 which transmits pressurized hydraulic fluid to either 
input port 380 or 382 of flow switching valve 362. The transmission of 
pressurized hydraulic fluid from pilot valve 378 to a specific one of the 
input ports 380 or 382 causes pressurized hydraulic fluid to flow through 
motor 364 in either a first or a second direction which determines whether 
spreader 300 is translated in either a first or a second direction across 
bridge 320. 
When valve 356 is displaced into the "off" position, hydraulic cylinder 310 
is deenergized, causing gate 308 to close and seal off the widthwise slot 
in the lower portion of hopper 302. The flow of hydraulic fluid to 
hydraulic motor 364 is also terminated and the movement of the spreader is 
stopped. Flow control valve 360 can be adjusted to vary the translation 
velocity of spreader 300 to assist in achieving a desired material 
distribution density. 
Referring now to FIGS. 22, 26-28 and 30, the bridge length adjustment means 
which permits the material spreader system of the present invention to 
continue operating within a reduced width section will now be described in 
detail. Many of the reference numbers to be used in connection with the 
description of the structure disclosed in FIGS. 22, 26-28 and 30 have 
previously been used in connection with FIGS. 17 and 21 and indicate 
structural elements of the embodiment now under discussion which performs 
substantially identical functions as those elements described previously. 
When the material spreader system of the present invention is being 
utilized to spread topping material over the full width section of a 
plastic surface, the first support means of the first and second bridge 
translation units (indicated by reference Nos. 234, 236, 238, 240 and 398) 
is utilized to contact a supporting surface lying outside of the area of 
plastic material for the purpose of supporting the bridge. This first 
support means 383 includes a pair of telescopically adjustable wheel 
mounting brackets 236 which are coupled to each end of the bridge and 
which each include a fully castering wheel 234. Wheel mounting brackets 
236 are telescopically adjusted to an appropriate point and locked into 
position by a plurality of set bolts as discussed earlier. 
FIGS. 29 and 30 depict a detailed illustration of the manner in which 
second support means 385 which is coupled to each end of the bridge can be 
utilized to support one or both ends of the bridge can be utilized to 
support one or both ends of bridge 320 above the plastic surface as the 
bridge is laterally translated past a reduced width section of the plastic 
surface which includes a vertically oriented obstruction such as a column 
248. Second support means 385 includes wheel 238, screw jack assembly 240 
and roller support means indicated generally by reference No. 244. As 
discussed in detail above, roller support means 244 includes a clamp 
assembly 246 and a horizontally oriented track 250 which receive and 
support screw jack assembly 240. In the improved version of bridge 320 
presently under discussion, screw jack assembly 240 is rotated into the 
horizontal position depicted in FIG. 30A when not in use and is rotated 
into the vertically oriented position depicted in FIG. 30B for the purpose 
of engaging track 250. When the weight of a selected portion of bridge 320 
has been transferred to screw jack assembly 240, wheel mounting bracket 
236 together with wheel 234 are removed from that segment of bridge 320. 
The length of tracks 316 and 318 which support flanged wheel sets 314 and 
315 of spreader 300 can be continuously varied by sliding the 
telescopically adjustable track section 384 and 386 either toward or away 
from the end of bridge 320 as illustrated. FIGS. 26-28 depict the specific 
structural elements which are utilized to form track sections 384 and 386 
and to permit telescopic adjustment of those track sections with respect 
to bridge 320. Each track section 316 and 318 includes a vertically 
oriented spreader stop bracket 388 which is coupled to a telescoping track 
element 380. A securing bracket is coupled to the side support element 393 
of bridge 320 and supports track element 390 from below. A sufficient gap 
is maintained between the lower surface of track 316 and securing bracket 
392 to permit track element 390 to be telescopically adjusted as required. 
Each end of bridge 320 includes telescopically adjustable track sections 
384 and 386. These telescopic track sections are fabricated so that the 
overall length of bridge 320 can be adjusted to clear any vertically 
oriented obstructions of the type typically encountered. 
FIGS. 29A-F sequentially depicted the manner in which the weight of bridge 
320 can be transferred from wheel 234 and wheel mounting bracket 236 to 
wheel 238 and screw jack assembly 240. FIGS. 29A and B depict track 
section 386 in the extended position, while FIGS. 29C and D depict track 
section 386 in the retracted position. FIG. 29F depicts the configuration 
of bridge 320 after it has been translated past vertically oriented 
obstruction 248. In this "normal" operating configuration, screw jack 
assemblies 240 have been rotated back into the horizontal or stored 
position, the weight of the depicted end of bridge 320 is being supported 
by wheels 234 and track sections 384 and 386 have been telescopically 
extended to an appropriate length to permit spreader 300 to dispense 
topping material right up to the edge of the plastic concrete surface. 
Referring now to FIG. 22, means for varying the vertical separation between 
bridge 320 and the surface of the plastic substance will now be described 
in detail. A pair of vertically oriented end plates 394 are coupled to 
each end of bridge 320. A single bridge translation unit which includes 
wheel 234, wheel mounting bracket 236, wheel 238 and screw jack assembly 
240, is coupled to one of the two end plates 384. By removing the grouping 
of three securing devices designated by reference number 396 from both the 
front and back surface of each translation unit mounting bracket 398, 
bracket 398 can be vertically adjusted with respect to end plate 394 and 
coupled at any given elevation to bracket 394. Adjustment of all four 
mounting brackets 398 of bridge 320 permit the overall elevation of bridge 
320 to be controlled as desired to thereby vary the vertical separation 
between spreader 300 and the surface of the plastic substance on which 
topping material is to be distributed. Any one of a number of different 
variables may dictate that spreader 300 be either closer to or further 
away from the surface of the plastic substance to achieve optimum material 
distribution onto that plastic surface. 
The vertically oriented support arms 400 and the various lengths of cross 
bracing 402 provide extra support and rigidity to bridge 320. The entire 
bridge assembly is bolted together and can be readily disassembled for 
storage or transportation to another job site. The side sections 404 of 
bridge 320 are fabricated in sections and are joined together by securing 
means as is indicated by reference number 406. 
It can now be seen that the spreader disclosed above which includes a 
totally self-contained hydraulic system operates automatically to 
repeatedly traverse bridge 320 for the purpose of distributing topping 
material onto a plastic surface. In order to achieve the most uniform 
possible distribution, spreader 300 typically traverses bridge 320 
approximately four or more times before bridge 320 is laterally displaced 
along the length of the plastic surface. After the desired number of 
passes has been completed by spreader 300, the spreader operator actuates 
arm 358 which deenergizes spreader drive motor 364 and closes gate 308. 
Bridge 320 is then laterally displaced a distance approximately equal to 
the length of the widthwise slot in the hopper 302. 
It will be apparent to those skilled in the art that the materials spreader 
system disclosed above may be modified in numerous ways and may assume 
many embodiments other than the preferred forms specifically set out and 
described above. For example, many different hydraulic system 
configurations could be utilized to achieve substantially the same result 
that is achieved by using the specific configuration of hydraulic 
components disclosed above. In addition, totally different means for 
reversing the direction of travel of the spreader could readily be adapted 
to operate with the specific embodiment of the invention disclosed above 
and would be obvious to one of ordinary skill in the art. Numerous other 
types of modifications would be readily apparent to one skilled in the 
art. Accordingly it is intended by the appended claims to cover all such 
modifications of the invention which fall within the broad scope of the 
material spreader invention disclosed above.