US3790981A

US3790981A - Surface sweeping machine equipped with gutter brush

Info

Publication number: US3790981A
Application number: US00289453A
Authority: US
Inventors: B Young
Original assignee: Individual
Current assignee: TYMCO Inc A TX CORP
Priority date: 1972-09-15
Filing date: 1972-09-15
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12

Abstract

A mobile road or like surface sweeping machine has a gutter brush and a brush driving hydraulic motor carried on a supporting structure which is mounted on the machine frame for compound vertical and horizontal swinging movements from a stowed position, with the brush in close to the machine frame and elevated and out of contact with the ground surface, to an extended operating position relatively wide of the frame and in pressure engagement with the surface to be swept. The brush rotates about a generally vertical although slightly tilted axis. A single power operated means, a hydraulic ram, operates the supporting structure to produce the compound vertical and horizontal swinging of the latter. When the brush encounters increased resistance to rotation, for example due to built-up or heavy debris, the pressure of the hydraulic fluid at the motor inlet increases, and the ram responds to that condition by forcing the brush into greater pressure contact with the surface, thereby ensuring greater capability of sweeping the obstruction.

Description

Young, deceased 1 Feb. 12, 1974 SURFACE SWEEPING MACHINE EQUIPPED WITH GUTTER BRUSH [76] Inventor: Bernard W. Young, deceased, late of PD. Box 2368, Waco, Tex. by Sophie Young, e'xecutrix [22 Filed: Sept. 15, 1972 21 Appl. No.: 289,453

[52] US. Cl....' 15/87, 15/340 Primary ExaminerEdward L. Roberts Attorney, Agent, or FirmBaldwin, Wight & Brown [57 ABSTRACT A mobile road or like surface sweeping machine has a gutter brush and a brush driving hydraulic motor carried on a supporting structure which is mounted on the machine frame for compound vertical and horizontal swinging movements from a stowed position,

with the brush in close to the machine frame and elevated and out of contact with the ground surface, to an extended operating position relatively wide of the frame and in pressure engagement with the surface to be swept. The brush rotates about a generally vertical although slightly tilted axis. A single power operated means, a hydraulic ram, operates the supporting structure to produce the compound vertical and horizontal swinging of the latter. When the brush encounters increased resistance to rotation, for example due to built-up or heavy debris, the pressure of the hydraulic fluid at the motor inlet increases, and the ram responds to that condition by forcing the brush into greater pressure contact with the surface, thereby ensuring greater capability of sweeping the obstruction.

29 Claims, 10 Drawing Figures LEFT SIDE Patented Feb. 12, 1974 3,7@@,%1

4 Sheets-Sheet 2 LEFT SIDE Patented Feb. 12, 1974 I 3,7,9W

4 Sheets-Sheet 55 FROM 0 LEFT SIDE Patented Feb. 12, 1974 4 Sheets-Sheet 4 SURFACESWEEPING MACHINE EQUIPPED WITH GUT-TIER BRUSH well known. In some, a gutter brush is mounted on a support which can be swung by one operating means from a stowed elevated position under or close in to the machine frame to an extended position outwardly of the frame, and which can be lowered by another operating means from its extended position to press the brush against the surface to be swept.

An object of the present invention is to provide a machine of the general class referred to embodying constructional improvements resulting in efficiency of operation, and simplicity of controlling the positioning of the brush.

Another object is to provide such a machine in which a single power operated means effects compound vertical and horizontal movements of a brush supporting structure to move the brush from a retractd and elevated stowed position outwardly from the machine frame and downwardly into engagement with the ground surface in one continous movement, and of course to move the brush reversely to stowed position.

A further-object is to provide equipment of the kind outlined above having means for precisely adjusting the amount of pressure exerted by the brush downwardly on the surface being swept.

A further object is to provide means for causing increased downward pressure to be exerted on the surface being swept automatically in response to increased resistance to rotation of the brush, such as would be encountered when the brush contacts a build-up of debris or other obstacle, the so applied increased downward pressure of the brush improving its ability to sweep the debris or obstacle instead of raising above it or otherwise yieldingto it. 7

Other objects of the invention will become apparent from a reading of the following description, the appended claims, and the accompanying drawings, in which:

FIG. 1 is a side elevational view of a mobile road or like surface cleaning machine provided with equipment embodying the invention;

FIG. 2 is a schematic top plan view of the machine shown in FIG. '1, showing some parts in outline only;

FIG. 3 is a perspective view of a gutter brush equipment mounted on a vehicle side frame member, the view being from above and from outwardly beyond the left side, i.e., the drivers side of the vehicle. The brushand its supporting structure are shown in an intermediate position, that is between a fully stowed position in close to the vehicle frame and an extended position for operation in gutters;

FIG. 4 is an exploded perspective view of a supporting structure, and a hydraulic motor and rotatable brush mounted thereon;

FIG. 5 is a perspective view similar to FIG. 3 but showing the supporting structure, hydraulic motor and brush in the two extreme positions, viz, POSITION I retracted to lift the brush from the ground and to stow it close to the vehicle frame, and POSITION II in which the brush has been swung out laterally with compound downward movement to bring it into contact with the surface to be cleaned;

FIG. 6 is a schematic diagram of a hydraulic circuit for operating the brush rotating motor and brush positioning means by which the brush is selectively moved to its POSITION I and POSITION II indicated in FIG. 5. In FIG. 6, valves in the hydraulic circuit are set for moving the motor and brush to POSITION II in which 7 the brush is extended laterally and is moved downwardly into pressure engagement with the ground and for maintaining the motor and brush in that position during operation;

FIG. 7 is a detailed cross-section on the line 77 of FIG. 6;

FIG. 8 is a detailed cross-section on the line 8-8 of FIG. 6;

FIG. 9 is a schematic hydraulic circuit diagram according to FIG. 6, but with the valves set for retracting the brush inwardly toward the vehicle and upwardly out of contact with the ground to POSITION I and maintaining it in that position; and

FIG. 10 is a simplified hydraulic circuit diagram showing hydraulic equipment for operating two gutter brushes, one on each side of the vehicle.

The invention is illustrated as being embodied in a mobile road, street or the like surface cleaing machine conforming generally to that shown in US. Pat. No. 3,512,206 granted to Bernard W. Young May 19, 1970 for AIR FLOW SURFACE CLEANING APPARA- TUS. As shown in FIGS. 1 and 2, the machine includes a basic truck vehicle V having a chassis frame F including longitudinal side members 1, 1' respectively at the left or drivers side of the vehicle and at the right side thereof. A motor housing is indicated generally at 2, and a cab is indicated at 3. The machine includes a pick-up head 4 which extends transversely under the vehicle frame F above the surface to be cleaned. As explained in US Pat. No. 3,512,206, a blower S delivers air under pressure through a duct 6 into the pick-up head 4. Air is drawn from the pick-up head through a suction duct 7 into a bin 8 in which solids, dust, etc., picked up from the surface are deposited. The blower 5 takes its intake through a duct 9 which commumicates with the bin 8 whereby the latter is maintained under suction. No further details of the main pick-up equipment including the head 4 need be described here since they are fully described in the aforesaid US. Pat. No. 3,512,206 and do not in themselves constitute any part of the present invention. In fact, gutter brush equipment according to the present invention may also be used in association with other types of main brushing equipment including, inter alia, conventional rotatable cylindrical brushes which extend transversely across the vehicle. In any case, the gutter brush equipment according to the present invention is especially useful for reaching out and sweeping surfaces adjacent to curbs or walls or such vertical surfaces which cannot be reached by the main cleaning devices such as the pick-up head 4. The gutter brush according to the present invention thus supplements the action of the pickup head 4 by directing debris and dust inwardly toward the vehicle into position where it can be picked up by the pick-up head 4. Although a single gutter brush equipment mounted at one side of te mobile machine may be very useful in some circumstances, it generally is desirable to provide two such equipments, one on either side of the machine, so as to provide for cleaning a surface regardless of which side of the machine is run close to the gutter, wall or the like. The present invention is illustrated as including two gutter brushes mounted respectively on opposite sides of the machine, but since they are the same other than one being a mirror image of the other, only one gutter brush equipment, namely that mounted at the drivers side of the machine, will be described in detail.

BRUSH AND MOTOR MOUNTING Referring especially to FIGS. 1-5, an angle mounting bracket is secured to the left frame side member 1 by a bolt 11 passing through a hole 12 in the bracket and a hole 13 in the member 1, and by a bolt 14 passing through one of three holes 15 in the bracket 10 and a hole 16 in the frame member 1. For achieving a purpose later to be explained, the bolt 14 may be passed through any one of the three holes 15 in the bracket 10 to give the latter a desired tilt and also to tilt the brush.

A brush positioning supporting structure means generally designated ST, mounted on the bracket 10, carries a rotary hydraulic motor M which in turn carries a disk-like brush B. The brush B is mounted for rotation coaxially with the motor M on a substantially or generally vertical but somewhat tilted axis.

The supporting structure ST includes a boom 17 which is mounted for horizontal and vertical pivotal movement at a first location designated Ll on the bracket 10. A plate 17a mounts the motor M and brush B at a second location L2 on the boom 17. Power operated force applying means, as shown a double acting ram 18, is mounted for horizontal and vertical pivotal movements at a third location L3 on the bracket 10. The ram 18 is connected to the boom 17 at a location remote from the first and third locations L1 and L3 respectively, and relatively adjacent to the second location L2.

The operating means, i.e., the hydraulic ram 18, is of the differential acting type and includes a cylinder component 19, a double acting piston component 20 reciprocal therein, and a piston rod 21. The effective pressure responsive area of the piston 20 at the face thereof from which the rod 21 extends is less than the effective pressure area on the opposite face. Thus, if equal unit pressures are applied to thetwo opposed faces of the piston 20, the net force will be effective to extend the rod 21. In the form shown, the rod component 21 is connected to the boom 17 by a screw 22 extending through a hole in the flattened end of the rod and into a lug 23 on the boom.

Considering more particularly the mounting of the boom on the frame bracket at location L1, a bearing post 24 is mounted on the bracket 10 to provide upper and lower lugs 25 formed with aligned holes 26. A cross member 27 is provided with aligned vertical pintles 28 journalled in the lug holes 26 and with horizontal pintles 29. The inner end of the boom 17 is formed as a clevis having horizontally spaced lugs 30 apertured to receive the horizontal pintles 29 of the cross member 27. It is apparent that by virtue of the connections at the location L1 the boom 17 may have compounded horizontal swinging movement and vertical swinging movement.

The cylinder component 19 may also have compounded vertical and horizontal swinging movements about the location L3. A bearing post 31 mounted on the bracket 10 is provided with horizontally spaced lugs 32 formed with holes 33. A cross piece generally designated 34 is formed with horizontal pintles 35 which are received in the holes 33 in the lugs 32. The cross piece 34 is also provided with vertical pintles 36 which are received in holes 38 in spaced ears 37 fast with the cylinder component 19.

Inasmuch as the piston component 20 and rod 21 can rotate about their common axis in the cylinder 19, there may also be a compound movement of the cylinder component 19 with respect to the boom 17, such movement including pivoting about the bolt 22 and also twisting or rotating of the piston 20 and rod 21 in the cylinder 19 as may be required to avoid binding.

Closely associated with and in a sense functioning as a part of the supporting structure ST is a coiled tension spring 39 connected at one end to the frame bracket 10 by an anchor 40 and connected at its other end to an adjusting screw 41 threaded into a lug 42 on the boom 17 adjacent the motor and brush mounting. The spring biases the supporting structure ST to swing about the location L1 vertically and horizontally to move the brush in close to the frame member 1 and move it upwardly out of contact with the ground surface, this being POSITION I required for moving the equipment while not using it for brushing. The spring 39 is, however, yieldable to permit the brush to be swung outwardly and downwardly into operating position as explained later.

The hydraulic circuit illustrated in FIGS. 6 and 9 provides power for effecting the vertical and horizontal swinging of the boom required for selectively positioning the brush in stowed position in close to the machine frame and up out of contact with the ground (POS- TION I and to extend it to operative position in contact with the ground (POSITION II). In the preferred arrangement, pressure is applied to both sides of the piston 20 to swing the brush outwardly into operative position and downwardly, and is applied to only the smaller effective area side of the piston 20 to return the brush to its stowed position. Controlling of the circuit for performing these operations will be explained later, it being sufficient for the present to consider only broadly the two controlling conditions, namely one in which the differential acting hydraulic ram holds or returns the brush to stowed position and the other in which the ram extends the brush to operative position. It should be noted here that the spring 39 acts in concert with that force on the ram piston 20 which tends to move the brush to its retracted or stowed position. Tightening the spring increases the vertical or lifting force applied to the boom more than it increases the force tending to swing the boom in horizontally.

When fluid under pressure is applied to both sides of the piston 20, the pressure acting on the larger effective area side of the piston extends the latter with the result that the boom 17 is swung outwardly and downwardly from POSITION I to POSITION II as shown in FIG. 5.

This will position the brush relatively widely spaced outwardly from the vehicle so as to work close to a curb or wall and at the same time the brush will be pressed downwardly into engagement with the ground. This extension of the ram is dominated by fluid pressure acting on the larger effective area side of the piston 20 even though this action is opposed both by fluid pressure acting on the piston face of less effective area as well as the tension of the spring 39. The tension of the spring 39 may be adjusted by way of the adjusting .screw 41 so as to obtain the proper balance required for smooth extending and retracting operations of the boom and brush. To stow the boom and brush in nonoperating position, fluid under pressure is applied to only the rod face of the piston 20, the opposite face of the piston being exposed to exhaust. The pressure acting on the rod face of the piston, augmented by the force of the spring 39, returns the boom 17 to POSI- TION l.

The compound horizontal and vertical movement of the brush which takes place during these settings may be understood clearly be referring to the diagrammatic trace of a point A on the common axis of the hydraulic motor M and brush B shown in FIG. 5. In moving about a center O of the cross piece 27 at the location Ll, the point A traces a'path Pl on an imaginary sphere having its center at O. The vertical projection of the path P1 on the ground is shown at P2. The dimension indication H represents the height of the point A above the ground when the ram is retracted and the partsare stowed (POSITION I). Comparison of the dimension h with the dimension H shows the degree of lowering of the point A toward the ground when the ram is extended to swing the supporting structure ST to POSITION II.

In connection with the performance of the compounded vertical and horizontal swinging movements of the boom 17, it is pointed out that the ram l8 is connected for vertical and horizontal pivotal movements to the frame bracket 10 at location L3 which is spaced above and inwardly toward the frame member 1 from the location L1 at which the boom is connected for vertical and horizontal swinging movements to the frame bracket 10. It is also pointed out that the spring anchor 40 is positioned between and above locations L1 and L3.

It is preferred that the circular brush, which is rotatable about a substantially vertical axis, be tilted slightly to the vertical so as to engage the ground initially and with greater force toward the front of the vehicle, this being well known with respect to gutter or the like circularbrushes. The rear of the brush with respect to the travelling frame preferably is clear of the ground or just barely touches it so that the brush rotating in the.

direction of the arrow a in FIG. 2 will move dirt, debris and the like inwardly toward the machine in front of the .main pick-up equipment 4. The amount of tilt of of the piston of the ram 18 to swing the brush outwardly' relatively wide of the frame F and downwardly into operating position in which the brush is held in the generally vertical axis of the brush required may be adjusted by selecting which of the three holes 15 in the frame bracket 10 isto be aligned with the hole 16 in the frame member 1 and secured by the bolt 14.

HYDRAULIC CIRCUIT pressure engagement with the surface being swept. The motor M and ram 18 are included in the hydraulic circuit also comprising a supply and exhaust tank T, a pump P, an operations control valve OCV, a sequence valve SV, a rate-of-flow valve RFV, and conduit connections described below. The pump is not of the constant volume delivery type and its delivery pressure can adjust to the load. A conventional stock pump is used.

The operations control valve OCV may be a conven-' tional four-way valve having a casing 42 formed with

ports

43, 44, 45 and 46, and a rotor 47 formed with arcuate passages or

long ports

48, 49 and a straightthrough passage 50. Detent or like means, not shown, hold the rotor 47 releasably in the selected set position. The sequence valve SV, so called because it in part controls the sequence of swinging the supporting structure ST outwardly and downwardly and applying increased pressure to the brush at certain times, includes a body 51 which is bored to receive a cyindrical insert 52 threaded into the body at 53. The inner end portion of the insert 52 is of reduced outer diameter and is hollow and closed at its upper end by a transverse wall 53 provided with an O-ring 54 engaging the wall of the body bore to prevent flow of fluid past the outside of the wall 53. A valve seat fitting 55 is threaded into the end 53 to provide communication between the body bore above the wall 53 and a chamber 56 within the hollow of the insert 52, the chamber extending outwardly partially to surround the insert 52 within the body bore wall. The communication provided by the valve seat member 55 is controlled by a poppet valve 57 device urged on to the seat by a spring 58, the loading of which may be adjusted by turning a screw plug 59. A series of relatively small holes 60 extending through the cylindrical wall of the insert 52 adjacent the end wall 53 and a series of relatively larger holes 61 extending through the insert cylindrical wall spaced downwardly from the holes 60 provide communication between the chamber 56 in the hollow of the insert and the surrounding chamber extension between the outside of the cylindrical insert wall and the wall of the bore in the body 51.

When the operation control OCV is set as shown in FIG. 6, the pump P delivers fluid through a main supply conduit 62 through operation control

valve OCV ports

43, 48 and 44 to a primary service conduit 63 into the chamber 64 in the body of the valve SV above the insert wall 53. Fluid under pressure is applied from the chamber 64 through a branch service conduit 65 and rate-of-flow valve RFV to the head end of the ram 19, that is the cylinder end in which the piston faceof larger effective area is presented. The conduit 65 bypasses the

poppet valve device

55, 57. The rate-of-flow control valve RFC may be any form of needle or other throttle valve design which is constantly open and functions to control the rate of fluid flow through the .branch conduit 65 to the ram as distinguished from controlling pressure per se. It will be noted that when the poppet valve 57 element in the sequence valve SV is open as shown in FIG. 6, there is relatively open communication between the primary service conduit 63 and the head end of the ram cylinder save, of course, the effect of the valve RFV in controlling rate of flow to that end of the cylinder.

Pressure acting from the primary service service conduit 63 in the valve chamber 64 and valve seat 55 passage opens the poppet valve 57 against the loading of the spring 58, permitting fluid under pressure to flow into the chamber 56, and out through the

holes

60 and 61 into the outer chamber between the insert 52 and the valve body bore wall. From these chambers, fluid under pressure flows through a conduit 66 to the inlet side of the motor M, driving the latter to rotate the brush. Pressure fluid is discharged from the motor through a motor discharge conduit 67 and through passage 68 in the valve body 51 to return to the tank T via operation

control valve ports

45, 49 and 46 and an exhaust conduit 68 opening into the tank.

Opening of the poppet valve 57 also enables the application of pressure through a branch conduit 69 to the rod end of the ram cylinder, that is the end at the side of the cylinder of relatively smaller effective area. As previously stated in the description of the supporting structure ST and its operation by the ram 18, when fluid is applied to both sides of the piston the pressure exerted upon the piston face of larger effective area dominates and extends the ram to swing the structure ST outwardly and downwardly. The net force with which the brush is pressed against the surface being swept may be adjusted by varying the hydraulic pressure acting in the ram. This may be done by adjusting the loading on the spring 58. Increasing the load on the spring 58 and thereby requiring more pressure to open the poppet valve 57 increases the net effective hydraulic pressure acting on the ram so that the brush is forced downwardly to exert increased pressure on the surface being cleaned. Decreasing the load on the spring 58, for example by turning the adjusting plug 59 outwardly, has the reverse effect. The pressure exerted by the brush on the surface being swept can also be adjusted by varying the tensile loading of the spring 39 as previously described. Thus, it is possible to provide a very precise regulation of the pressure exerted by the brush on the surface being swept. This is quite an important factor since pressure requirements'may change according to the nature of the ground surface itself, the heaviness or amount of accumulation of trash or debris, or the relatively new or relatively worn condition of the brush bristles or fingers.

In order to return the supporting structure ST, motor M and brush B to stowed POSITION I with the brush elevated and in close to the machine frame F, the rotor of the operations control valve OCV is turned to the position shown in FIG. 9. Pressure fluid will then be delivered through the

valve OCV ports

43, 48 and 45 to the motor discharge conduit 67 and thence back reversely through the motor M and through the branch conduit 66 to the chamber 56 in the sequence valve SV. Pressure of this fluid in the chamber 56 will close the poppet valve 57 on the seat 55, the valve 57 then acting as a check valve preventing further flow through the valve seat. Fluid flowing reversely from the motor M through the branch conduit 66 will pass up through the chamber 56 into the branch conduit 69 and thence into the rod end of the ram 18. At the same time, the opposite end of the ram cylinder will be open to exhaust through the branch conduit 65, valve RFV, the chamber 64, the primary service conduit 63, the operation

control valve ports

44, 49 and 46, and the exhaust conduit 68. Thus, no effective fluid pressure is exerted on the head end of the ram piston while pressure is continued to be exerted on the rod end of the piston providing a force which, together with that exerted by the spring 39, moves the structure ST to swing inwardly to the frame 1 and upwardly to position the brush above and out of contact with the swept surface. The valve RFV limits the speed of retraction of the ram and returning of the structure ST to POSITION I.

The rotor of the operation control valve OCV may be set to position the straight-through passage 50 to connect the

ports

43 and 46 so that pump discharge flowing through the main supply conduit 62 will be returned through the exhaust conduit 68 to the tank T, the pump then running idly. At this setting of the valve OCV, means, specifically lands on the valve body 47, block off both

ports

44 and 45 so that fluid is trapped in both ends of the ram cylinder 19 and the ram piston 20 will be held against movement so that the supporting structure ST will be maintained in the position which it occupied when the rotor of the valve OCV was set to block off the

ports

44 and 45.

An important feature of the present invention is the hydraulic circuit relation of the brush driving motor M and the power operated ram 18 which results in pressing of the brush against the surface being swept more firmly when the brush encounters built-up debris or an obstacle or the like producing increased resistance to rotation of the brush and consequent increase in the motor torque. When the brush B encounters such an obstacle, the torque required to keep rotating the brush increases and this causes an increase in pressure in the branch conduit 66 leading to the motor inlet and also an increase in fluid pressure in the

valve chambers

56 and 64 and

branch conduits

65 and 69 leading to the ram 18. The result is that greater or increased net effective hydraulic pressure force is applied to the ram to cause the brush to press against the surface being swept with increased pressure which ensures better capability of dislodging the encountered obstacle or built-up debris and sweeping it in front of the main pick-up head 4. The ram 18 responds to the increased pressure condition in the hydraulic input to the motor for applying this increased pressure of the brush on the surface. It is emphasized that when the brush encounters such an obstacle the hydraulic circuit and its components react to cause the brush to be pressed downwardly more firmly in contact with the surface being swept rather than to shirk the job and relieve pressure of the brush against the surface to permit it to ride over the obstruction. Nevertheless, if the brush should encounter something more in the nature of an immovable obstruction such as a hard lump of concrete on the surface or a vertical obstruction such as a post, the hydraulic connections will permit the ram to be forcibly contracted by effort exerted mechanically on the brush or the supporting structure ST. Thus, the supporting structure and with it the brush and motor can be forced inwardly and upwardly when encountering such a stubborn obstruction so as to avoid damage to the mechanism. Once the obstruction has been passed, as permitted by yielding of the structure ST, the latter will be returned to its normal operating position without any adjustment of the valves being required.

The foregoing description has reference to the gutter brush B, motor M and cooperating mechanism and bydraulic parts and equipment for operating the brush B mounted at the left or drivers side of the machine. Ordinarily a mirror image, or at least similar, counterpart is mounted at the right side. This is indicated in FIGS. 1 and 2 by showing some right side parts designated by primed characters corresponding to the left side designating characters. Thus, the right side parts include the brush B, supporting structure S'T', ram 18', and so on.

FIG. shows diagrammatically how the pump P and tank T may serve hydraulic systems for operating both left and right side brush equipments. Separate sets of valves, separate conduits, and separate hydraulic rams for the left and right sides are provided. The valves, the conduits, and the ram for the right side equipment are designated by primed characters corresponding to the characters denoting the left side components.

Usually only one of the two sets of equipment (right and left side) is used, depending on whether the left or right side of the machine is to run close to a curb or gutter. Therefore, the hydraulic systems are operable independently of one another by separate operation control valves OCV and O'C'V'. However, there may be times when it is useful to increase the width of the swath being brushed irrespective of the proximity of a curb or wall. In such cases, the two gutter brush equipments may be operated simultaneously. In the form of machine illustrated, the total swath swept would be increased by the amount each brush is extended laterally beyond the adjacent end of the trailing pick-up head 4.

The construction illustrated and described includes the presently preferred embodiment of the invention, but it is intended that the disclosure be illustrative rather than definitive, the invention being defined in the claims.

I claim:

1. A mobile road or like surface sweeping machine comprising a frame; a brush mounted on said frame for rotation in contact with the surface to be swept; a motor for rotating said brush; brush positioning means for moving said brush downwardly to press on said surface; means for delivering power to said motor; and force applying means associated with said power delivering means and connected to said brush positioning means for operating the latter to move said brush downwardly and being responsive to a condition in the input to said motor for applying increased force to said brush positioning means when said brush encounters built-up debris or an obstacle or the like with resultant resistance to rotation of said brush and running of said motor, said application of increased force to the brush positioning means pressing the brush with increased firmness against said surface thereby better to ensure sweeping of the debris, obstacle or the like.

2. Machine according to claim 1 in which said motor and said force applying means are fluid pressure operated andin which said force applying means is responsive to an increase in pressure of fluid in the fluid pressure operated motor inlet supply for applying said increased force to said brush positioning means.

3. A mobile road or like surface sweeping machine comprising a frame; a motor; a rotary brush connected to said motor to be driven thereby; a support structure on which said brush is carried; means mounting said structure movably on said frame to position said brush for rotation about a substantially vertical axis and for enabling said structure and said brush to be moved upwardly relatively away from the surface to'be swept and downwardly for pressure engagement of said brush with said surface; operating means connected to said structure and being operable for moving said supporting structure and said brush downwardly into pressure engagement of said brush with said surface; means for supplying power to said motor for operating the latter to rotate said brush;force applying means for subjecting said operating means to force for moving said structure and said brush downwardly to cause said brush to press against said surface; and means interconnecting said power supplying means and said force applying means and making the latter responsive to increased resistance to rotation of said brush due to encounterng built-up debris or an obstacle or the like for increasing the force applied to said force applying means and thereby increasing the pressure exerted by said brush on said surface.

4. Machine according to claim 3 including a device in said interconnecting means which is adjustable for varying the force applied to said operating means and thereby varying the pressure exerted by said brush on said surface.

5. A mobile road or like surface sweeping machine comprising a frame; a rotary hydraulic motor; a rotary brush operatively connected to said motor to be driven thereby; a supporting structure on which said motor and brush are carried; means mounting said structure movably on said frame to position said motor and brush for rotation of the latter about a substantially vertical axis and for enabling said structure and said brush to be moved upwardly relatively away from the surface to be swept and downwardly for pressure engagement of said brush with said surface; a source of hydraulic pressure fluid; a hydraulic ram operatively connected to said supporting structure and being operable for moving said brush downwardly into pressure engagement with said surface; and fluid supply conduit means connecting said pressure source to said motor and to said ram with the inlet side of the motor communicating with said ram, whereby increase in resistance to rotation of said brush and motor caused by the brushs encountering a build up of debris or an obstacle or the like on said surface will increase the pressure in said supply conduit means and cause said ram to force said structure and brush downwardly and cause the brush to exert increased downward pressure on said surface.

6. Sweeping machine according to claim 5 including a valve in said conduit means for controlling the pressure exerted by said brush on said surface.

7. Sweeping machine according to claim 6 in which said valve is in said conduit means between said pressure source and said hydraulic motor, is pressure operated to open position to direct fluid flow to said motor, and is adjustable to vary the pressure required to open it.

8. Sweeping machine according to claim 7 in which said valve comprises a seat at the valve intake communicating with said pressure source; means defining a valve chamber communicating with said seat; a poppet valve element movable in said chamber; and a spring yieldably urging said poppet valve element to close said seat, said conduit means including a conduit connection between said pressure source and said ram bypassing said valve and a conduit connection between said valve chamber and said hydraulic motor, whereby pressure fluid delivered to said motor must pass through-the pressure-opened valve.

9. Sweeping machine according to claim in which said hydraulic ram comprises a cylinder and a double acting piston therein having a first face of relatively large effective area, and a second face of relatively small effective area; and in which said fluid supply conduit means includes a first conduit connection leading from said source into said cylinder on said first face side of said piston, and other conduit connections leading from said source both to said cylinder on the opposite side of said piston and to the inlet side of said mo- I01.

10. Sweeping machine according to claim 5 including a spring biasing said structure and said brush upwardly.

l1. Sweeping machine according to claim 9 including a spring biasing said structure and said brush upwardly in concert with the application of fluid pressure on said second face of said piston.

12. Sweeping machine according to claim 9 including a pressure responsive valve interposed between said source and said other conduit connections, said valve having an element biased toward closed position and being openable in response to pressure on the source side of said valve to permit fluid to flow under pressure through said other conduit connections to said cylinder on said opposite side of said piston and to the inlet side of said motor.

13. Sweeping machine according to claim 9 including a constantly open rate-of-flow control valve in said first conduit connection.

14. Sweeping machine according to claim 12 including a constantly open rate-of-flow control valve in said first conduit connection.

15. A mobile road or like surface sweeping machine comprising a frame; a rotary hydraulic motor; a rotary brush operatively connected to said motor to be driven thereby; a supporting structure on which said motor and brush are carried; means mounting said structure movably on said frame to position said motor and brush for rotation of the latter about a substantially vertical axis and for enabling said structure and said brush to be moved upwardly relatively away from the surface to be swept and downwardly for pressure engagement of said brush with said surface; a hydraulic ram comprising a cylinder component and a double acting piston component relatively movable therein and having a first face of relatively large effective area and a second face of relatively small effective area; means connecting the movable one of said components to said supporting structure for tending to move said structure and brush upwardly under the action of fluid pressure on said second face of said piston component, and being operable for moving said support and brush downwardly under the action of a fluid pressure on said first face of said piston component; a source of fluid pressure; a main supply conduit connected to said source; an exhaust conduit; service conduit means connected to said cylinder component on both sides of said piston component and to the inlet side of said motor; a motor discharge conduit; and an operations control valve for selectively (1) connecting said main supply conduit to said service conduit means and simultaneously connecting said exhaust conduit to said motor discharge conduit, and (2) for selectively connecting said main supply conduit to said motor discharge conduit and connecting said service conduit means to said exhaust conduit.

16. Sweeping machine according to claim 15 in which said operations control valve includes settable means for blocking all fluid flow to or from said service conduit means and to or from said motor discharge conduit, whereby no fluid power is transmitted to said motor and fluid is trapped in both ends of said cylinder component and prevents relative movement of the cylinder and piston components, thereby holding said structure and brush stationary on said frame.

17. Sweeping machine according to claim 16 in which said source of fluid pressure is a pump, and in which said operations control valve settable means includes a passage for connecting said main supply to said exhaust conduit when said operations control valve settable means is set to block fluid flow to or from said service conduit means and through said motor discharge conduit.

18. Sweeping machine according to claim 15 including a spring connected to said structure and biasing the latter and said brush upwardly.

19. Sweeping machine according to claim 15 in which said service conduit means comprises a primary conduit connected to said main supply conduit; a first branch service conduit means providing constant communication between said primary conduit and said cylinder componet on said first face side of said piston component; a second branch service conduit means connected to said primary and to said motor and to said cylinder component on said second face side of said piston component; and a pressure responsive valve in said second branch service conduit biased to closed condition and being openable in response to fluid pressure in said primary conduit.

20. A mobile road or like surface sweeping machine comprising a frame; a brush mounted on'said frame for vertical positioning movements and for rotation in contact with a surface to be swept when positioned in a lower position; differentially acting hydraulic means for positioning said brush selectively in said lower position or in an upper position out of contact with said surface; means for applying fluid pressure to said hydraulic means to exert relatively small force on said brush to urge the brush to said upper position, and to urge said brush oppositely to said lower position with relatively large force overcoming said relatively small force, whereby to hold said brush in pressure contact with said surface; and operations control means for discontinuing application of fluid pressure for exerting said relatively large force while continuing the exertion of said relatively small force, thereby enabling the latter to move said brush to its upper position.

21. A mobile road or like surface sweeping machine comprising a frame; a boom; a rotary brush mounted on said boom for rotation about a substantially vertical axis; means pivotally mounting said boom on said frame at a first location for compounded simultaneous universal swinging movements generally horizontally and generally vertically to thereby move said brush outwardly and downwardly from a retracted elevated position relatively close to a side of said frame to a lowered position relatively wide of said frame and in brushing engagement with the surface to be swept; and a single hydraulic ram including a cylinder component and a piston component therein for causing said boom to perform said compounded simultaneous movements, said brush being mounted on said boom at a second location spaced from said first location, one of said ram coinponents being pivoted universally to said frame at a third location thereon spaced from said first location, and the other of said ram components being pivoted to said boom at a location spaced from said first location.

22. Machine according to claim 21 in which said third location is spaced both vertically and horizontally from said first location.

23. Machine according to claim 22 in which said third location is spaced above said first location and is spaced horizontally from said first location toward the center of said frame.

24. Machine according to claim 23 further including a spring anchored to said frame and connected to said boom and being loaded in a direction to urge said boom to swing about said first location upwardly and horizontally inwardly relatively to the center of said frame in opposition to the extension of said ram' 25. Machine according to claim 24 in which said spring is a tension spring which is anchored at one end to said frame at a point above and horizontally between said first and third locations, and is connected at its other end to said boom adjacent to said brush.

26. Machine according to claim 25 including means for adjusting the loading of said spring.

27. Machine according to claim 23 in which said hydraulic ram piston component is double acting with one face of larger area than the other face thereof, said machine further including a source of pressure fluid; conduit means for delivering fluid under pressure to said cylinder component at both faces of said piston component, the application of fluid pressure to said larger area face of said piston component driving the latter to extend said ram in opposition to the application of fluid pressure to said other face of said piston component.

28. Machine according to claim 27 including valve means for selectively effecting delivery of fluid to said cylinder component on both sides of said piston component and alternatively relieving fluid pressure from said cylinder component on the side of the larger piston component face area while continuing to apply fluid pressure in said cylinder component on the opposite face of said piston component, whereby to retract said ram and simultaneously swing said boom inwardly with respect to said frame and upwardly away from said surface.

29. Machine according to claim 28 including a hydraulic motor mounted on said boom for driving said brush rotatably; and a conduit connection for delivering a flow of pressure fluid from said source to said motor when pressure fluid is delivered to said cylinder component at both sides of said piston component.

Claims

1. A mobile road or like surface sweeping machine comprising a frame; a brush mounted on said frame for rotation in contact with the surface to be swept; a motor for rotating said brush; brush positioning means for moving said brush downwardly to press on said surface; means for delivering power to said motor; and force applying means associated with said power delivering means and connected to said brush positioning means for operating the latter to move said brush downwardly and being responsive to a condition in the input to said motor for applying increased force to said brush positioning means when said brush encounters builtup debris or an obstacle or the like with resultant resistance to rotation of said brush and running of said motor, said application of increased force to the brush positioning means pressing the brush with increased firmness against said surface thereby better to ensure sweeping of the debris, obstacle or the like.

2. Machine according to claim 1 in which said motor and said force applying means are fluid pressure operated and in which saId force applying means is responsive to an increase in pressure of fluid in the fluid pressure operated motor inlet supply for applying said increased force to said brush positioning means.

3. A mobile road or like surface sweeping machine comprising a frame; a motor; a rotary brush connected to said motor to be driven thereby; a support structure on which said brush is carried; means mounting said structure movably on said frame to position said brush for rotation about a substantially vertical axis and for enabling said structure and said brush to be moved upwardly relatively away from the surface to be swept and downwardly for pressure engagement of said brush with said surface; operating means connected to said structure and being operable for moving said supporting structure and said brush downwardly into pressure engagement of said brush with said surface; means for supplying power to said motor for operating the latter to rotate said brush; force applying means for subjecting said operating means to force for moving said structure and said brush downwardly to cause said brush to press against said surface; and means interconnecting said power supplying means and said force applying means and making the latter responsive to increased resistance to rotation of said brush due to encounterng built-up debris or an obstacle or the like for increasing the force applied to said force applying means and thereby increasing the pressure exerted by said brush on said surface.

5. A mobile road or like surface sweeping machine comprising a frame; a rotary hydraulic motor; a rotary brush operatively connected to said motor to be driven thereby; a supporting structure on which said motor and brush are carried; means mounting said structure movably on said frame to position said motor and brush for rotation of the latter about a substantially vertical axis and for enabling said structure and said brush to be moved upwardly relatively away from the surface to be swept and downwardly for pressure engagement of said brush with said surface; a source of hydraulic pressure fluid; a hydraulic ram operatively connected to said supporting structure and being operable for moving said brush downwardly into pressure engagement with said surface; and fluid supply conduit means connecting said pressure source to said motor and to said ram with the inlet side of the motor communicating with said ram, whereby increase in resistance to rotation of said brush and motor caused by the brush''s encountering a build up of debris or an obstacle or the like on said surface will increase the pressure in said supply conduit means and cause said ram to force said structure and brush downwardly and cause the brush to exert increased downward pressure on said surface.

8. Sweeping machine according to claim 7 in which said valve comprises a seat at the valve intake communicating with said pressure source; means defining a valve chamber communicating with said seat; a poppet valve element movable in said chamber; and a spring yieldably urging said poppet valve element to close said seat, said conduit means including a conduit connection between said pressure source and said ram by-passing said valve and a conduit connection between said valve chamber and said hydraulic motor, whereby pressure fluid delivered to said motor must pass through the pressure-opeNed valve.

9. Sweeping machine according to claim 5 in which said hydraulic ram comprises a cylinder and a double acting piston therein having a first face of relatively large effective area, and a second face of relatively small effective area; and in which said fluid supply conduit means includes a first conduit connection leading from said source into said cylinder on said first face side of said piston, and other conduit connections leading from said source both to said cylinder on the opposite side of said piston and to the inlet side of said motor.

11. Sweeping machine according to claim 9 including a spring biasing said structure and said brush upwardly in concert with the application of fluid pressure on said second face of said piston.

20. A mobile road or like surface sweeping machine comprising a frame; a brush mounted on said frame for vertical positioning movements and for rotation in contact with a surface to be swept when positioned in a lower position; differentially acting hydraulic means for positioning said brush selectively in said lower position or in an upper position out of contact with said surface; means for applying fluid pressure to said hydraulic means to exert relatively small force on said brush to urge the brush to said upper position, and to urge said brush oppositely to said lower position with relatively large force overcoming said relatively small force, whereby to hold said brush in pressure contact with said surface; and operations control means for discontinuing application of fluid pressure for exerting said relatively large force while continuing the exertion of said relatively small force, thereby enabling the latter to move said brush to its upper position.

21. A mobile road or like surface sweeping machine comprising a frame; a boom; a rotary brush mounted on said boom for rotation about a substantially vertical axis; means pivotally mounting said boom on said frame at a first location for compounded simultaneous universal swinging movements generally horizontally and generally vertically to thereby move said brush outwardly and downwardly from a retracted elevated position relatively close to a side of said frame to a lowered position relatively wide of said frame and in brushing engagement with the surface to be swept; and a single hydraulic ram including a cylinder component and a piston component therein for causing said boom to perform said compounded simultaneous movements, said brush being mounted on said boom at a second location spaced from said first location, one of said ram components being pivoted universally to said frame at a third location thereon spaced from said first location, and the other of said ram components being pivoted to said boom at a location spaced from said first location.

24. Machine according to claim 23 further including a spring anchored to said frame and connected to said boom and being loaded in a direction to urge said boom to swing about said first location upwardly and horizontally inwardly relatively to the center of said frame in opposition to the extension of said ram.

25. Machine according to claim 24 in which said spring is a tension spring which is anchored at one end to said frame at a point above and horizontally between said first and third locations, and is connected at its other end to said boom adjacent to said brush.