US 3165775 A
Description (OCR text may contain errors)
Jan. 19, 1965 M. w. LUTZ 3,165,775
' POWER SWEEPER DRIVE, VACUUM AND PROPULSION Filed Sept. 13, 1961 2 Sheets-Sheet l FILE. 1
Mac M Lurz Jan. 19, 1965 M. w. LUTZ 3,165,775
POWER SWEEPER DRIVE, VACUUM AND PROPULSION Filed Sept. 13, 1961 ILE: 5,
2 Sheets-Sheet 2 INVENTOR. Mac M 4072 Qu M. 8, J -gwwm v United States Patent Ofi ice 3,165,775 Fatented Jan. 19, 1965 3,165,775 POWER SWEEPER DRIVE, VACUUM AND PROPULSION Mac W. Lutz, Minneapolis, Minn, assignor to The G. H.
Tennant Company, Minneapolis, Minn, a corporation of Minnesota Filed Sept. 13, 1961, Ser. No. 137,853 4 Claims. (Cl. 15-340) This invention relates to power sweeping machines and more particularly to improvements in propulsion, vacuum systems, and other features. The invention particularly relates to improvements in the propulsion system, whereby a constant brush and vacuum speed of the machine may be maintained while the machine is driven either forwardly or reversely at any desired speed up to limiting speeds.
In power sweeping machines, the sweeping element, usually a cylindrical brush, with optionally a curb brush or brushes, are rotated at a constant or substantially constant speed, regardless of the speed of the sweeping vehicle. In some sweeping machines, this has been accomplished by providing separate power sources for the brush and propulsion components of the vehicle, whereas in other sweeping machines mechanical variable speed transmissions have been provided.
It is an object of the invention to provide a power sweeping machine wherein the main sweeping brush is driven directly from the engine and propulsion of the vehicle is by way of a hydraulic transmission. It is another object of the invention to provide an improved power sweeping machine having a hydraulic transmission wherein all hydraulic components which are likely to leak during service are contained in the same vessel which constitutes a reservoir for the hydraulic fluid. It is a further object of the invention to provide an improved power sweeping machine in which separate hydraulic drives are provided for propulsion and other power consuming circuits, but in which a common enclosure is provided for all hydraulic components likely to leak, with the enclosure also serving as a common sump. It is a further object of the invention to provide a power sweeping machine wherein cooling of the hydraulic fluid is accomplished by utilization of the cleaned air of the vacuum system of the machine.
Other and further objects are those inherent in the invention herein illustrated, described and claimed and will be apparent as the description proceeds.
To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these eing indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
The invention is illustrated with reference to the drawwhich may be used as a basic arrangement for embodying the invention are illustrated in copending application,
Ser. No. 794,762, filed February 20, 1959, Patent No.
2,972,159, and copending applications of Ralph C. Peabody, Serial No. 137,865 filed of even date herewith, and Ralph C. Peabody and Keith N. Krier, Ser. No. 137,864 filed of even date herewith, which show in greater detail the mechanical configuration of the particular sweeping machine illustrated in the instant application. As the details of the mechanical structure of the sweeping machine may be varied, it is therefore to be understood that the particular machine'herein described in merely illustrative and is not a limitation of the invention.
In FIGURE 1 the machine comprises a wheeled frame generally designated 10, having front wheels 11 and a steering and propulsion wheel 12. The wheel 12 is supported on a suitable bracket 14 which is mounted in a vertical spindle 15 in the bearing 16, and the spindle is provided with a sidearm 17 and drag link 18, the drag link being connected to a suitable steering apparatus so that the wheel 12 can be turned about the axis of spindle 15 for steering motion. The bracket 14 which carries the wheel also serves to support a hydraulic motor generally designated 20 which is attached by suitable bolts 21 to the outer surfaces of the bracket 14. The axle 22 on Which wheel 12 is mounted is driven by the hydraulic motor 28 through a suitable reduction gearing schematically illustrated at 24.
On the sweeping machine frame 30 there is a transverse open bottom housing or enclosure 31 which serves to contain the cylindrical brush 32, which is mounted on radius rods, not shown, and is arranged to be driven by a belt drive 33 extending through transmission, herein illustrated by the dotted line 34, to a power take-off pulley 35 of constant speed power source 36. The enclosure 31 has an opening across its front face, extending from sidewall to sidewall of the enclosure, and provided with a flexible gasket 37 all around. I
The machine has a pivot shaft at 40 upon which a pair of forwardly extending support arms 41 are provided, the shaft 40 also being provided with a crank 42 which is coupled to the piston rod 44 of the hydraulic cylinder 45, the base of which is suitably pivoted on the machine frame. Hydraulic supply and return lines 46 and 47 serve this hydraulic cylinder. When pressure is introduced into the cylinder the arms 41 will be swung up in the direction of arrow 43.
On the parallel arms 41 there is mounted a debris, dirt and dust receiving receptacle and filter unit generally designated 50. This unit consists of a dust and debris receiving pan 51 which is connected at the bracing 52 to a housing 53 containing dust filter equipment. The upper part of the housing 53 is connected to a plenum chamber 54 which is in communication with the top (clean) side of the filter within the housing 53. The plenum chamber has a suction outlet at 55 which seats upon a soft gasket 56 which surrounds a port 57 connected to the suction line 58. The port and suction line are on the frame of the machine proper. connects with the inlet 59 of a suction blower 60 which is mounted on the machine frame. The suction blower is mechanically driven by any suitable mechanical drive 61 from a second power output pulley 62 of engine or power source 35.
The, filter in housing 53 serves to remove the dust from the air, and the dust residue falls into the pan 51. The pan 51 has a rearwardly extending mouth portion 64 which fits into the opening in the front part of the sweeping housing 31, being sealed thereto by the soft gasket 37. The brush 32 revolves clockwise as shown in FIGURE 1, and sweeps dirt, debris, and dust in the direction of arrow 65 into the pan 51, where the heavier The suction line 58' particles of dirt and debris accumulate. The dust, carried by the air which also enters the mouth 64 of the pan from the sweeping housing 31, follows the path of arrows 66 and after passing up through the filter 53, where the air is cleaned, the clean air continues its travel at 67 through the plenum chamber 54 and thence enters the port 57 and tube 58 as shown by arrow 68 and continues through tube 58 to the inlet of the suction blower 60.
The clean air is discharged from the suction blower as shown by arrow 69, and is used as a coolant. The hydraulic lines 70 and 71 from hydraulic pumps, which willbe described, serve as pressure and return lines, for the hydraulic motor 20. In one or both of these lines 70-71, there is put a suitable radiator, as at 71A for line 71. This hydraulic line thus-serves as a cooler for the fluid in the hydraulic system. The cooler or radiator 71A is physically situated in the path of the clean air discharged at 69 from the suction blower.
Pivoted at '75 on the machine frame is a forwardly extending arm 76 which serves as a mounting for hydraulic motor 77, the output shaft 78 of which extends downwardly and carries a curb brush 79. Hydraulic lines 80 and 81 serve as pressure and return lines respectively for the hydraulic motor 77.
A major improvement of this invention resides in the arrangement of the hydraulic components, which will now be described.
All hydraulic components which are likely to leak, such as pumps, pressure release valves, control valves, etc. are arranged together in a single tank generally desig nated 82, which also serves as the sump for the hydraulic fluid. The only portions of the hydraulic equipment which are external to the tank 82 are the hydraulic connecting lines themselves, and the hydraulic motors and cylinders that are used at varying places on the vehicle. The tank contains, in this illustrative embodiment, two duplex hydraulic pumps 86 and 88 on a common shaft, the pumps being shown thus for convenience in illustration. A duplex hydraulic pump is one which contains two separate pumps assembled on a common drive shaft. Separate pumps may be used in place of duplex pumps if desired, but duplex pumps are preferred because of economy and smaller size. Separate drive shafts for each duplex pump or for each separate section of the pumps may be used where mechanically expedient.
In the illustrated embodiment the output shaft 84 of the engine or power source 36 is coupled or belt-connected toa shaft 85, extending through the sidewall of container 82 at a level sufficiently high so as not to be exposed to excessive amounts of hydraulic fluid splashing Within the container 82, and so as not to be exposed to any pressure. A shaft seal 85A sutficient to keep out dust and grime and to hold in oil is used. The shaft 85 is connected to one of the duplex pumps 86 which contains two separate pump sections 86A and 86B. The shaft from the latter pump is connected at 87 to another duplex hydraulic purnp 88 containing separate pump sections 88A and 883. Where separate input shafts are used, these are connected to the power source outside the tank 82 and a separate shaft seal provided for each shaft, or one input shaft can be used and gear connected inside the tank to as many pump input shafts as are used. Accordingly, as illustrated, one mechanical input shaft 85 serves to drive all of the hydraulic pumps used in the system but more than one can be used, if desired, with the same results. While duplex pumps are indicated in this illustration, separate pumps may be used, and more or less than the number of pumps shown may be used, depending on how many hydraulic items (cylinders, motors, etc.) are used. At least two pumps are Qused for propulsion, as will be described.
According to the present invention, pump sections 86A and 86B are used for driving the curb brush motor and the hydraulic cylinder 45, respectively, whereas duplex pump sections 88A and 88B are used in interconnected relationship for supplying hydraulic fluid under pressure for the main hydraulic propulsion motor 20. Each of these pumps has an inlet 86AI, 86BI, 88AI, and 88BI. All the inlets are connected to a common manifold 89 which connects to an inlet filter 0 which reaches into the bottom of the sump, in tank 82. The outlet 86AO connects through line 91 and junction 92 to a pressure regulator valve 93 which is preset so as to pass hydraulic fluid at a certain pressure. Any hydraulic fluid that is passed by the valve 93 is returned to the sump via arrow 94. The sump is indicated by the letter S. From junction 92. a line extends through throttle control valve S 5 and then to a coupling 96 on the external Wall of the tank or sump-container 82. External line is connected to the coupling 96, and extends to the motor '77, the return line 81 being connected to a similar coupling 97, which connects on the interior of the tank to a line delivering to the sump S.
The control valve 15 for the curb brush motor 77 is manipulated through a valve stem 116 which extends down through the tank wall to the valve and is connected at 117 to the lever 11%. This lever has a raised position shown in full lines,.which closes the valve and hence stops the motor 77 and the brush 79, and a lowered position shown in dotted line where the motor 77 and brush are run at full speed, which is a constant speed. Intermediate positions may be chosen for throttling the motor and hence reducing the speed of the curb brush, if desired, but normally the curb brush is run at a constant speed while the machine is in operation.
From the outlet 86130 of pump 863, a line 100 extends through junction 101 to a pressure release valve 102 which is set at any desired pressure, so as to open and deliver hydraulic fluid to the sump S when the pressure in line .100 reaches a stipulated amount. From junction 101 a line extends through throttle valve 104 which is normally closed, and then via line 105 to the coupling 1&6 on the wall of the tank-sump structure 82. From the external side of the coupling 106, hydraulic line 46 extends to the pressure side of :hydraulic cylinder 45. The valve 104 is controlled by a mechanical stern 107 which is normally lifted upwardly by the collar 108 and spring 109 within the tank. The stem passes through a gland 110 in the tank wall and is connected at 111 to a control handle 112 Which is accordingly normally held in the full line position as shown in FIGURE 1. In this position a circuit is opened through the valve 104 from junction 101 to the sump return line 114, and pump 86B accordingly merely circulates the oil but does not labor to produce pressure. When the handle 112 is pushed down to the dump position, the stem 107 will move valve 104- to the position where it closes the circuit from junction 101 to the sump line 114 and opens the circuit from junction 101 to line 105, which accordingly compels the pump 8613 to deliver pressure to the line 46, thereby operating the hydraulic cylinder 45. When pressure is dc livered to the cylinder 45, the arms 41 are swung up in V the direction of arrow 48 thereby moving the entire duct,
filter and debris collector pan, which is the entity 50 to an elevated and tilted position which permits the accumulated residue to be dumped from the filling mouth 64.
Any leakage and entrapped air around the piston in cylinder 45 is returned via line 47 which connects to the coupling 115 in the tank side wall, the inside portion of said coupling being connected to a line delivering to the sump S. When the dust receptacle and filter unit 50 is elevated the vacuum circuit is broken at the flexible gasket 56.
The output 38AO of pump 88A is connected via line to junction 121 and then through a pressure release valve 123 which is set at a certain low pressure, such as 500 pounds. When the pressure exceeds this com paratively low pressure, the valve 123 will open and deliver the flow to the sump line 124. From junction 121 a circuit extends through the check valve 125 which connects to junction 126 on line 127 which leads to theoutg let 8330 of the high pressure pump 8833. From the junction 126 a line is connected through the pressure regulator'valve 128 which is set at a high control pressure such as 1,500 psi. If this pressure is exceeded, valve 12% opens and the flow is delivered via line 123 to the sump.
From junction 126 lin 139 extends through junction 131 and line 132 to the inlet 134 of a reversing valve 135. This reversing valve has four ports, namely an inlet port 134, an outlet port 135 and two delivery ports 137 and 138. Figures 2 and 3 illustrate the two oper tive positions of the valve 135. The valve has an operating shaft 14% and a lever arm 141 which is connected to a stem' 142, which will be described hereinafter. When the stem is pushed down, the arm 141 will be in the position shown in FIGURES 1 and 2 and in this condition port 134 will be connected to port 137 and port will be connected to port 135. When the stern 1452 is raised, the control arm 141 on the valve is moved to the position shown in FEGURE '5, and in this condition the port 134- is connected to the port 13% and the port 136 is connected to the port 137.
From junction $.31, line 144 connects to the body 145 of a variable pressure release valve, having a control stem 1% and an outlet port 147. The stemis needleshaped and when it is pushed down the outlet port 147 is restricted, and in an extreme condition will be closed. Depending upon the position of the stem 145, th outlet port 147 may be either closed or restricted in any degree desired, or left entirely open. The port 147 delivers to the sump.
tems 146 and 142 are aligned with one another and each have an operating plate on their top; thus plate 142A is on the top of stem M2 and the plate 146A is on the top of stem 146. These plates are adapted to be engaged by cams 159 and 151 on a common rock shaft 152 that is mounted for rocking movement on suitable bearings 354 and 155. The rock shaft 152 passes through a gland 53 in the wall of tank 32, and on the outside of the container is provided with a foot pedal 166 which may be depressed by the toe of an operat rs foot as shown by the arrow F or depressed by the heel of his foot as shown by the arrow R. When depressed by the heel ot the foot, the cam 151'will go out of engagement with the plate 142A on the stem 42 and the spring 1-51 will cause the stem 14-2 to rise, thereby moving the valve 135 to the position shown in FIGURE. 3, and in this condition pressure is applied to the line 71 and thence through the propulsion motor 26 and via return line 7'9 and through the valve 135 to the sump exhaust port 136 of the valve. in this condition the propulsion motor Zil rotates in a direction such as to drive the vehicle in a reverse" direction; When the shaft 152 is rocked forwardly by the toe of the foot in the direction of arrow F, the cam 151 will engage the plate 142A on the stern 142 thereby depressing the stem and causing valve 135 to assume the position shown in F1- URES 1 and 2 in which event ports 13% and 1.37 will be connected thereby delivering oil under pressure via line 7%} to motor 2%, and the return will be via line 71 to port 138 and thence through the valve 135 to the sump delivery port 136. Under such conditions the propulsion motor 26* is rotated in such a direction as to drive the vehicle forward.
Speed control is managed by the cam 15%. As the foot pedal res is melted increasing y in either the forward or the rearward direction, the cam 159 will push may therefore be rotated in either direction at any speed 7 esired.
In this system the vehicle propulsion is illustrated as by way or two pumps 88A and 833 which are provided 6 with relief valves 123 and 128, such valves being adjusted so that one (valve 123) opens at a lower pressure (say 500 psi.) and the other opens at a higher pressure (say 1500 psi). The outputs of these pumps are connected via check valve 125 to output junction 126 and thence to junction 131 of the motor circuit. For smooth control and ability to climb grades, not less than two pumps are used but more than two can be used.
When more than two pumps are used, they are set parallel to pumps 83A and 83B, and each pump outlet is provided with a relief valve which is set to open at a pressure somewhat higher than the pump next below (i.e. to the left in FIGURE 1). Each outlet circuit is crossconnected to the adjacent pump through a check valve which allows it to deliver to the output junction 131 but prevents baclolow to the pump which has the next 10 er pressure (i.e. to the left in FIGURE ,1). Thus, for example, should a third such pump be used in theFIGURE l CllCUllI l't'WOuld have an output line delivering to a junction" to line 13% and an overpressure relief valve (similar to valves 123 and 123) but set to open at a higher pressure than valve 128 and a check valve inserted between its junction (on line 136) and junction tee with such valve connected to pass flow to the right. Thus, two or more pumps in multiple may be used.
Inoperation, such two (or more) pumps work cooperatively as follows:
The hydraulic pressure at junction 131 is determined by the load on motor 28, which is, of course, the power load needed to accelerate and drive the sweeper vehicle. When the sweeper is at rest, and pedal 160 is operated to direct the vehicle to move (forwardly or backwardly, it makes no difference), closure of valve 145-146-147 pinches oil the bypass how of hydraulic fluid, and the pressure increases. Since. the sweeper starts at zero velocity, the pressure increases to a hi h pressure, due to the load forces needed for acceleration Both pumps initially deliver to junction 131, but as the pressure rises, valve 123 opens and dumps the flow from pump 83A to sump, and check valve 125 closes. The pressure will continue to rise, with increasing power'output of motor 24}, until under overload conditions (i.e. stall) valve 128 will open and relieve pump 88B. Normally, however, valve 328 remains closed and as the vehicle reaches working speed the power needed to maintain speed decreases and therefore the pressure at junction 13}; decreases accordingly until it is again below the opening pressure of valve 123 of pump 38A. When this happens, the output volumes of the pumps are again added and a larger volume of oil at a lower pressure is circulated for moving the, sweeper at a higher speed. When three or' more pumps are used, the pumps cut out and bypass each at a sucessively higher pressure during accel oration and again pica up load as the pressure at junction 132i falls pursuant attaining velocity.
When a grade is reached the load on motor 20 also increases and with this the pressure at junction 131 increases, and as the pressure at such junction reaches the opening pressure of the relief valve of the pump farthest to the left (in FIGURE 1), (example valve 123) such valve will'open and the adjacent check valve (example 7 "valve (128 will continue to carry the load, but the depending upon ambient temperature and the work load.
Cooling of the fluid via the cooling coil 71A is therefore accomplished upon the whole fluid within the hydraulic In this way the fluid is kept at a temperature,
system. well within operating range. V
The entire group of hydraluic components which might normally leak, such as the pump, regulator valves, control valves, etc., are all contained within the tank 82 which has couplings mounted at suitable levels around it, to accommodate the external tubes and pipes leading to the motor pressure cylinders, etc. which the device serves. Accordingly, the only components of the system which are external to the tank 82 are the pipes 46, 47, 70, 71, 80, 81, and hydraulic motors 26 and 77 and the hydraulic cylinder 45. If two curb brushes are used or more than one cylinder is used, separate pumps and circuits are supplied as needed but using the same mode of location and connection as herein described. Many hydraulic components will bleed or drip through necessary glands and openings, and this is almost impossible to stop under ordinary circumstances. If rep-air or replacement should be attempted for every leak, no matter how small, the maintenance cost is exceedingly high. By locating the components which are likely to bleed or drip Within the common tank which also serves as a sump, such minor leakage will be caught, and may therefore be tolerated. This is a major factor in reduction of maintenance expense in connection with the machine. By having separable connectors on the outside of the sump-tank 82, the entire sump-tank 82 may thus be disconnected, and a replacement unit inserted, merely by making connections at the external couplings, heretofore mentioned. This greatly simplifies field maintenance.
The tank 82 is provided with a filler neck 83 which is provided (inside the tank) with a removable screen 98, which prevents introduction of dirt and grit into the hydraulic system when filling tank 82. In addition, the filler neck 83 is closed by a high grade filter 99 which can be either cleanable and re-usable or one that is merely replaced when dirty. The filler neck thus acts as a carefully filtered breather for the entire hydraulic system, a factor which is of first importance in a sweeping machine which is frequently operated under dusty conditions. The oil inlet filter 90 is chosen as a very efficient filter and its inlet is somewhat elevated above the bottom of the tank. Thus the oil in all hydraulic circuits is filtered as it is used and is additionally protected against contamination by the common filtered breather of the system.
The tank 82 may be located wherever convenient on the vehicle for convenience of engineering, manufacture and maintenance.
The cooling of thehydraulic fluid, which is illustrated as being accomplished by a cooling coil in FIGURE 1, may also be accomplished by directing the flow from the suction blower 60 against fins placed on one or more surfaces of the tank 82. This is illustrated in FIGURE 4 wherein the tank 82 is in every respect the same as shown in FIGURE 1, except that it is provided with a plurality of fins 180 on its lower surface. These fins are arranged to be hit by a blast of air from the exhaust pipe 182 of the suction blower 60, the exhaust pipe in this case being expanded as a manifold 184'so as conveniently to deliver the flow of air against all of the fins. The location of the cooling fins in respect to the blower 60 and on the tank can be varied as convenient, the only criteria being that the fins be of suflicient area and so located as to carry away theheat from the oil within the tank, and the duct work from the blower being so located as to distribute the cooling air over the fins. In this way the hydraulic fluid within the, tank 82 is adequately cooled, and as a consequence a cooling coil71A may be eliminated from the lines 70-71 serving the propulsion motor 20.
What I claim is:
1. A power sweeper comprising a wheeled vehicle having propulsion and steering wheel means thereon, a manual steering control connected to the steering wheel means for steering the vehicle, hydraulic motor means having a pair of hydraulic connections thereon, said motor means being connected to the wheel means for propelling the vehicle, a power source on the vehicle, a sweeping enclosure on the vehicle, a sweeping brush on the vehicle in said enclosure, mechanical power transmission means connecting the power source and brush for operating the brush, a debris receiving hopper mounted on the vehicle for movement from a position contiguous to the sweeping enciosure wherein it receives swept material to a dumping position, hydraulic hopper moving means on the vehicle connected to the hopper for moving it to the dumping position, said hydraulic means including a pressure connection and a return connection, a suction blower connected to the power source so as to be directly driven therefrom, said suction blower having a suction inlet on the vehicle and an air outlet, said hopper having a port thereon which communicates with said suction inlet on the vehicle when the hopper is in a position contiguous to the sweeping enclosure, a closed casing on the vehicle forming an enclosure for hydraulic components and a common sump for hydraulic fluid for all hydraulic circuits, a plurality of hydraulic pumps in said casing, one for the hydraulic motor means and another for said hydraulic hopper moving means, said pumps being connected to be mechanically driven by power connection means extending from said pumps and through the casing wall and to said power source, each such pump having an inlet extending to the sump for receiving hydraulic fluid therefrom, each pump including control valve means and overpressure relief valve means in the casing and connected via a separate pressure line to a pressure connection on the casing wall, said control valve means for one of said pumps including a variable orifice flow control valve in the pressure line to said hydraulic motor means, a separate line from each pressure connection and exterior to the casing, and one such line extending to one hydraulic connection of the hydraulic motor and another such line extending to the pressure connection of the hydraulic hopper moving means and return lines from the other hydraulic connection of said hydraulic motor and from the return connection on said hydraulic hopper moving means extending back through said casing for delivering to said sump, and control means external to the casing and extending through the casing to the control valve means of each pressure line in the casing.
2. The power sweeper of claim 1 further characterized in that a portion of the hydraulic lines external to the casing are placed in the path of air discharged from said blower for cooling the hydraulic fluid of the system.
3. The power sweeper of claim 1 further characterized in that the air discharge of the suction blower is directed against the casing for cooling it.
4. A power sweeper comprising a wheeled vehicle having propulsion and steering wheel means thereon, a manual steering control connected to the steering wheel means for steering the vehicle, hydraulic motor means, said hydraulic motor means being connected to the wheel means for propelling the vehicle, a power source on the vehicle, a sweeping enclosure on the vehicle, a sweeping brush on the vehicle in said enclosure, first mechanical power transmission means connecting the power source and brush for opera-ting the brush, a debris receiving hopper mounted on the vehicle for movement from a position contiguous to the sweeping enclosure wherein it receives swept material to a dumping position, hydraulic hopper moving means on the vehicle connected to the hopper for moving it to the dumping position, a suction blower, second mechanical power transmission means connecting the power source and suction blower for operating the blower, said suction blower having a suction inlet on the vehicle and a discharge air outlet, said hopper having a port thereon which communicates with said suction inlet on the vehicle when the hopper is in a position contiguous to the sweeping enclosure, a closed casing on the vehicle forming an enclosure for hydraulic components and a common sump for hydraulic fluid for all 9 hydraulic circuits, hydraulic pump means in said closed casing, pressure and return conduit means for supplying fluid under pressure from said hydraulic pump means-to said hydraulic hopper moving means and said hydraulic motor means respectively, said pump means being connected to be mechanically driven by power connection means extending from said pump means and through the casing wall and to said power source, control valve means in said conduit means for controllingthe fluid under pressure from said hydraulic pump means, a variable orifice flow control valve in the pressure conduit means carrying fluid under pressure to said hydraulic motor means, and a cooling section in one portion of said conduit means, and means to'direct the discharge air from said suction blower over the cooling portion of said conduit means.
References Cited by the Examiner UNITED STATES PATENTS 3/37 Roeder 6053 7/39 Conradson 60-52 FOREIGN PATENTS Great Britain.
WALTER A. SCHEEL, Primary Examiner. V
CHARLfi A. WILLMUTH, Examiner.