US2960829A

US2960829A - Hydraulic control for motor graders

Info

Publication number: US2960829A
Application number: US719638A
Authority: US
Inventors: George E Ross
Original assignee: Galion Iron Works & Manufacturing Co
Current assignee: Galion Iron Works & Manufacturing Co
Priority date: 1958-03-06
Filing date: 1958-03-06
Publication date: 1960-11-22
Anticipated expiration: 1977-11-22

Description

Nov. 22, 1960 G. E. Ross HYDRAULIC CONTROL FOR MOTOR GRADERS Filed March 6, 1958 INVENToR; Cir-:ORGE E. R055 BY @M5015 HTT'Y.

United States Patent O HYDRAULIC CONTROL FOR MOTOR GRADERS George E. Ross, Nevada, Ohio, assignor to The Galion Iron Works & Manufacturing Company, a corporation of Ohio Filed Mar. 6, 1958, Ser. No. 719,638

1 Claim. (Cl. 60-52) The instant invention relates to motor graders and more particularly to a novel hydraulic control circuit for operating the various devices of the motor grader.

It is the object of this invention to provide a novel hydraulic control circuit for a motor grader, in which certain of the devices of the grader are operated at a constant speed by the hydraulic control circuit.

It is another object of the instant invention to provide a novel hydraulic control circuit for a motor grader, in which hydraulic fluid is supplied to a steering valve at a constant rate for operating the steering means of the grader at a constant speed.

It is a further object of the instant invention to provide a novel hydraulic control circuit for a motor grader, in which hydraulic uid is supplied at a constant rate to a plurality of hydraulic controls for the mold lift, the wheel leaning means, the power shift mold board, the plow and the scarier, for operating each of the latter at a constant speed.

It is still another object of the instant invention to provide a novel hydraulic control circuit for a motor grader, in which there is provided a plurality of hydraulic controls for the circle, the side shift, the mold lift, the wheel leaning means, the power shift mold board, the plow and the scarier, with the hydraulic fluid being supplied to the circle and side shift hydraulic controls directly from a pump which delivers the uid from a reservoir tank, and including hydraulic means for delivering the uid from the circle and side shift hydraulic controls at a constant rate to the hydraulic controls for the mold lift, the wheel leaning means, the power shift mold board, the plow and the scarier, for operating the latter devices at a constant speed.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claim.

The drawing herein diagrammatically illustrates the novel hydraulic control circuit for the motor grader.

The instant invention is in a novel hydraulic control circuit for a motor grader, in which the mechanical elements of the grader may be of a conventional form, for example as illustrated in Pat. No. 2,340,169, issued January 25, 1944, for Road Grader. The motor grader includes a mold board to which there is attached a blade. The mold board is secured to a circle which may be rotated through 360 for the purpose of adjusting the angle of the blade. The circle is mounted on a laterally shiftable frame for adjusting the position of the mold board vlaterally of the main frame of the motor grader, side shift means being provided for this purpose.

The mold board may also be shifted laterally with respect to the circle for extending the mold board and its 'blade to one side or the other of the main frame of the motor grader, and for this purpose the power shift mold Yboard control is provided. The controls for the motor grader also include a right hand and a left hand mold lift which are utilized to adjust the elevation of one side ICC or the other of the mold board and its blade. The righthand and left hand mold lift controls may also be operated together to elevate the mold board and blade.

The motor grader includes a pair of wheels at the front end thereof, which may be leaned in one direction or the other, depending on the operation of the motor grader, for' the purpose of counteracting forces which tend to shift the motor grader to one side or the other during the operation thereof. In conjunction with the leaning of the front wheels, these wheels may be steered for assisting the leaning of the front wheels in counteracting forcesv which tend to shift the motor grader to one side or the other during the operation thereof. The motor grader also includes a scan'iier which may be lowered into con-- tact with the ground, or raised from the ground so as toz be inactive, and for this purpose the motor grader con trols include a control for raising and lowering the scari fier. As an accessory device there may be provided a: plow for moving snow or a bulldozer blade, which is at-4 tached at the front end of the main frame of the grader. A control is provided for operating the plow, or the bulldozer blade. The plow, or the bulldozer blade, is not. normally attached to the grader, but is added when it is desired to use either of these devices, there being provided a single control for one or the other of these.

The above described structure of the motor grader isy conventional, and will be recognized as such by those skilled in the art. Accordingly, there is not included herein a detailed description of the same, since the various devices and the operating means therefor in the motor grader are not of themselves novel, the instant invention being in the hydaulic control circuit for controlling the operation of these devices.

Referring to the drawing, the novel hydraulic control circuit comprises a reservoir tank 1t) which contains a supply of hydraulic uid. A conduit 11 leads from the tank 10 to each of a pair of pumps .12, 13 which are arranged in tandem and are driven together from the grader motor, whereby the rate of delivery of hydraulic fluid by the pumps 12, 13 will vary in accordance with the speed of the grader motor. The pump 12 supplies hydraulic uid under pressure through conduit 14 for operating the steering means of the motor grader. The hydraulic pump 13 supplies hydraulic fluid under pressure through conduit 15 for operating the other devices of the motor grader.

The conduit 14, which leads from the pump 12, includes a relief valve 16 which is connected by a conduit 17 to a uid return line 13. The hydraulic uid is delivered by the line 14 through the pressure relief valve 16 to a bypass and restrictor type ow regulator 19, which includes a bypass line 20 connected to the return line 18. The ow regulator 19 regulates the How of hydraulic fluid to the steering valve 21, and maintains the supply of hydraulic tiuid to the valve 21 at a constant rate, irrespective of the rate of delivery of hydraulic fluid by pump 12. A pressure relief valve 22 is connected between the flow regulator 19 and the return line 1S to relieve any excess pressure in the hydraulic uid delivered to the steering valve 21.

The steering valve 21 is disposed at the operators station of the motor grader, and is operated by a steering wheel. The steering valve 21 is a rotary valve that is operated by rotation of the steering wheel, which permits the hydraulic uid to ow through the steering valve for the purpose of operating the hydraulic steering means, to turn the front wheels of the motor grader in accordance with the direction in which it is desired to operate the motor grader. The hydraulic uid discharges from the steering valve 21 through the discharge line 18.

The steering valve 21 and each of the other hydraulic controls for the` various operating devices of the motor grader are located at the operators station on the motor grader and disposed in a manifold 23, indicated diagrammatically by a broken line in the drawing.

The pump 13V delivers hydraulic iluid from the tank through theconduit 15'and-through a pressure relief valve 24,-which is connected by Va'line 25 to the `fluid return line26. The hydraulicuid that owsthrough the relief valve 24, is directed through the -hydraulic conduit 27 to a bank of hydraulic control valves which control the operation of the various devices of the motor grader, as Vis described hereinafter.

The hydraulic conduit 27 delivers-the hydraulic uid under pressure from the-pump 13 toa hydraulic controlV valve'28 for controlling the operation of the circle, and a second hydraulic control valve V29-for controlling theoperation ofthe side shift. YThe hydraulic control valves 2S,-

29 are secured to each other and the discharge of the valve 28 communicates directly with-the intake of the valve 29;` These valves are of a conventional type and each comprises a reciprocable spool mounted Within the valve casing, which in neutral position permits the hydraulicV fluid to flow freely through the Valve. The spool of each of the

valves

28, 29 may be reciprocated by means of an operating handle to either side of the neutral position thereof-for directing the ow of iluid in one direction or the other. A hydraulic conduit 30 is connected to the control valve 29 and receives the seepage of hydraulic uid from the control valves 28,v 29, and directs this seepage through the conduit 26 and the return conduit 31 to the tank 10,.V The hydraulic fluiddischarges from Y

theV control valves

28, 29 to a bypass and restrictor type oW regulator 34 which controls the rate of delivery of hydraulic fluid to the remaining control valves, by limiting the rate of delivery-'of hydraulic fluid to a predetermined maximum. The ow regulator 34 is connected Y to the fluid return line 18 by a conduit 35 to discharge the surplus of hydraulic uid. Below the ow regulator 34 there is a relief valve 36 connected to the seepage conduit 30 for the purpose of relieving any excessive pressure of the hydraulic uid that may occur at this point.

The hydraulic fluid, which is delivered from the ow regulator 34 at a predetermined maximum rate of flow, ows through a bank of six valves each of which is of the same type and construction as the valves 2S, 29. The valves 38, 39 control the operation of the right hand mold lift and the left hand mold lift, respectively. The valve 40 controls the operation of the wheelleaning means, the valve 41 controls the operation of the powerv shift mold board, the valve 42 controls the operation of Y the snow plow or bulldozer blade, and the valve 43 controls the operation of the scarifer. As in the case of

valves

28, 29, previously described, each of the valves 38V fluid discharges from the valves 38 to 43 through the.y

conduit 45, which directs the ow of hydraulieuid through the return conduit 31 to the reservoir tank .10.

The various

hydraulic control valves

28, 29, 38 to 43, are located at the operators station of thev motor grader, as part of the manifold 23, and each valve is provided with a handle for reciprocating the spool of the valve and, thereby, elfecting a control of the devices of the motor grader according to the direction in which theiluid flows through the valve being used at a given time. The hydraulic control Valves 28, 29, 38 to 43 may be of any suitable form, for example as illustrated in Pat. No. 2,486,087, issued October 25, 1949, for Hydraulic Valve. The .

valves

28, 29 are connected to each other for ow of the hydraulic uid therethrough, and the valves 38 to 43 are similarly connected to each other for the ow of hydraulic fluid therethrough, which connections may be made in the manner disclosed in said Pat. No. 2,486,087. In accordance with the invention, the rate at which the hydraulic iiuid is delivered to each of the control valves 38 to 43 is limited to a predetermined maximum, whereby the operating speed of the right and left hand mold lift, the wheel leaning means, the power shift mold board, the snow plow or bulldozer blade, and the scariiier is controlled in accordance with the rate of delivery of hydraulic fluid to the control valves 38 to 43. Similarly, the hydraulic uid delivered Vto the steering valve 21 is delivered at a constant rate, whereby the operation of the steering means is at a constant speed. Since vthe hydraulic iiuid for operating the steering means is delivered by the pump 12 independently of the pump 13, which delivers the hydraulic fluid to the other control valves, the

speed of operation of the steering means may be different.

from that of the other devices of the motor grader.

Obviously those skilled in the art may make various.

changes in the details and arrangement of parts without departing from the spirit and scope of the invention as.

defined by the claim hereto appended, and. applicant therefore wishes not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodimentof the invention, what it is desired to secure by ,Letters Patent of the United States is:

In a motor grader comprising a hydraulic control circuit for operating a plurality of individual hydraulic actuators, one hydraulic-actuator being provided for actuation of each of thecircle, the side shift, the right hand. mold lift, the wheel leaning means, the powershift. mold board,

the plow, the scariier, and the left hand mold lift, `said hydraulic control circuit including a rst bank of open.. center hydraulic control valves comprising an individual.

hydraulic control Valve for control ofthe respective hydraulic actuator for each of the circle-and theside shift,

and a second bankfof open center hydraulic control valves comprising an individual hydraulic control valve for control of the respective hydraulic .actuator for .each of the, right hand mold lift, the YWheel leaning means, the powerV shift mold board, the plow, the scarier, and the left hand mold lift, a pump for delivering .hydraulic fluid under pressure to the open center vinlet of the first valve bank at a variable rate of ow, a liuid conduit interconnecting the open center outlet of the first valve bank to the-open cen` ter inlet of the second valve bank fordirecting the flow kof hydraulic fluid from the rst valve bank to.the second valve bank, and a ow regulator valve in the interconnecting conduit means between the rst bank of hydraulic control valves and the second bank of hydraulic Vcontrol valves for limiting the rate of flow of hydraulic fluid to..