GB2206911A

GB2206911A - Improved method and apparatus for tilting dozer blades

Info

Publication number: GB2206911A
Application number: GB08804065A
Authority: GB
Inventors: Norman E Williams
Original assignee: Dresser Industries Inc
Current assignee: Dresser Industries Inc
Priority date: 1987-07-16
Filing date: 1988-02-22
Publication date: 1989-01-18
Also published as: DE3744063A1; JPS6424924A; IT1219945B; FR2618171A1; GB8804065D0; IT8848021A0

Description

1 - - t 1 2206911 1 IMPROVED METHOD AND APPARATUS FOR TILTING DOZER BLADES

IS

Background of the Invention

This invention relates generally to improved methods and apparatus for tilting dozer blades. More particularly, but not by way of limitation, this invention relates to improved method and apparat-us for tilting dozer blades wherein the tilting cylinder is connected between the blades and push arm of the dozer with a second adjusting means that permits the operator to compensate for pitch of the blade while maintaining full tilt capability.

The blades for dozers are attached to the dozer by a pair of spaced push arms. The arrangement is such that the blade can be raised or lowered about the pivotal attachment between the push arms and the dozer, can be pitched about the attachment between the blade and the push arms and can be tilted relative to the arms and the dozer generally about an axis substantially parallel to the longitudinal axis of the dozer. In contrast to tilting, pitching of the blade refers to its movement about a horizontal axis that. is generally perpendicular to the longitudinal axis of the dozer.

Apparatus for pitching and tilting bulldoze blades usually includes a pitch strut that extends between the blade and one of the push arms and that -2manually adjustable as to its length. The change in length causes the blade to pivot about its pivotal connection with the push arms, Near the opposite end of the blade, there is provided a tilt cylinder which in effect provides a means for hydraulically changing the length of a strut connecting the blade with the other push arm. To pitch tWe blade while avoiding tilt, the hydraulic cylinder must provide the same length of strut as the pitch strut resulting in pivoting of the blade about a horizontal axis that, as mentioned above, is generally perpendicular to the longitudinal axis of the dozer. Tilting of the blade is accomplished by actuating the hydraulic cylinder to a greater or lesser extent than the change in length of is the pitch strut so that a twisting force is applied to the dozer blade causing the blade to pivot or tilt about an axis parallel to the longitudinal axis of the dozer. 1 Pitch of the blade is required to efficiently handle the different types of material in which the blade is operating. For example, a cohesive, plastic material like clay requires a reduced cutting edge angle and a pitched back blade contour. A flowing dry material, like sand, is best handled when the blade is pitched forward.

Difficulty has arisen in providing the maximum tilt control for blades when the blade is pitched. Due to the limited amount of length change available from the tilt cylinder. pitching the blade forward or rearward means that the piston in the tilt cylinder will be closer to one end of its travel than the other.

Accordingly, if it is also desired to tilt the blade, and the tilt adjustment is In the direction of the shortened travel, it may not be possible to produce the degree of tilt desired.

Accordingly, an object of this invention is to 1 1 1 -3provide an improved method and apparatus for tilting dozer blades wherein an adjustment is provided in the strut containing the tilt cylinder that is utilized to match the pitch strut adjustment while maintaining the piston in the tilt cylinder in the centered position thereby providing the desired tilt in either direction even when the blade is pitched.

Summary of the Invention This invention provides an improved apparatus for tilting dozer blades and the like that includes a blade that is supported by and pivotal relative to elongated first and second push arms on a dozer and an adjustable strut that has one end connected to the first push arm and the other end connected to the blade and includes a turnbuckle between the ends for changing the length of the strut to pivot the blade relative to the arms. The improvement comprises tilt control means adjustably extending between the second push arm, and the blade that includes a cylinder member having a hollow interior. The tilt control means includes adjusting means connecting the cylinder member to the second arm, a piston movable in the interior of the cylinder member, and a piston rod that extends from the cylinder member and is connected to the piston and blade. Thus, the adjusting means is adjusted when the length of the strut is changed to pivot the blade thereby maintaining the piston substantially centrally located in the cylinder member providing maximum tilt control for the blade.

In another aspect, this invention contemplates an improved method for providing maximum tilt to a dozer blade when the blade is pitched. The improved method comprises the steps of pitching the blade by manually adjusting the length of the strut connecting the blade with the push arm on which the blade is i -4pivotally mounted, changing the length of a first length control of a tilt control that connects the blade with a second push arm, and actuating a hydraulic tilt control cylinder to change the length of the tilt control means to impose a twisting force on the blade, causing the blade to tilt. ' Brief Description of the Drawing

The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawing wherein like reference characters denote like parts in all views and wherein:

FIG. 1 is a perspective view of a dozer blade having the tilting apparatus constructed in accordance with the invention located thereon.

FIG. 2 is an enlarged end view of the blade of FIG. 1 showing the tilting apparatus in more detail.

FIG. 3 is an enlarged, fragmentary cross-sectional view illustrating another embodiment of a pitch control apparatus that can be used in the tilting apparatus of FIGS. 1 and 2.

Detailed Description of the Preferred

Embodiment Referring to the drawing and to-FIG. 1 in particular, shown therein is a dozer blade 10 that is arranged to be connected to a dozer (not shown) by a left push arm 12 and a right push arm 14. Although not illustratedi the push arms 12 and 14 are pivotally connected to the dozer.

The left push arm 12 is also connected by a pivotal connection 16 with the blade 10. The right push arm 14 is connected by a pivotal connection 18 with the blade 10. The axes of the pivotal connections i It :k 16 and 18 coincide so that the blade 10 can pivot relative to the arms 12 and 14. To fix the pivotal relationship between the blade 10 and the arms 12, there is provided an adjustable strut 20 that has a threaded member 22 connected to the blade 10 and a threaded member 24 that is connected to the arm 12. Adjustably connecting the members 22 and 24-is an internally threaded member 26 which Is commonly referred to as a turnbuckle.

On the back of the blade 10 as shown in FIG.

1, there appear two pair of spaced mounting brackets 28 and 30 whichi as can be seen in FIG. 2# receive one end of a piston rod 32 extending from a cylinder 34. The brackets 28 and 30. the piston rod 32 and the cylinder 34 are utilized on the dozer (not shown) for the purpose of raising and lowering the blade 10.

FIG. 2 illustrates a complex strut that extends between the push arm 14 and the blade 10 and is generally referred to as the tilt control means 36.

The tilt control means 36 includes a hollov, cylinder member 38 having a piston 40 slidingly located therein. The piston 40 is connected by piston rod 42 and a ball and socket joint 44 with the blade 10. The tilt control means 36 also includes adjusting means generally designated by the reference character 46.

The adjusting means 46 includes a threaded end 48 which forms part of the cylinder member 38, a threaded member 50 having one end pivotally connected at 52 with the push arm 141 and a turnbuckle 53. The threaded end 48 of the cylinder member 38 and the member 50 are held in end to end relationship by the turnbuckle 53 which is hollow and threaded on the interior thereof as indicated by the dash lines 54. A lever 56 extends through the turnbuckle 53t generally perpendicularly thereto, to enable the operator of the dozer to rotate the turnbuckle 53 and adjust the length of the tilt control means 36 as desired.

Operation of the Preferred Embodiment When it is desired to pitch the blade 10, that is to rotate the blade 10 about an axis generally perpendicular to a longitudinal axis 58 of the dozer, the operator rotates the turnbuckle 26 in the appropriate direction to cause the strut 20 to increase or decrease in length. If no tilt is to be applied to the blade 10, it is necessary to permit the piston 40 to move in the cylinder member 38 so that the blade 10 can also pivot about the pivotal connection 18, and thus remain in the horizontal pos ition. As can be appreciated, when this has been accomplished, the piston 40 is located closer to one end of the cylinder member 38 than the other. thus limiting the possible tilting movement which can be imparted to the blade 10.

In order to avoid this problem, the operator rotates the turnbuckle 53 by means of the lever 56, changing the length of the tilt control means 36 by an amount equal to the change in length of the strut 20. As this adjustment is madei the piston 40 remains in the cylinder member 38 at a central position substantially as illustrated in FIG. 2.

When it is desired to impart tilt to the blade 10. that is to cause the blade 10 to rotate about an axis generally parallel to the dozer axis 58, hydraulic pressure is applied in the cylinder member 38 causing the piston 40 to move in the appropriate direction. The imposition of such twisting force on the blade 10 since the strut 20 remains a constant length, causes the blade 10 to either tilt to the left or to the right depending on which side of the piston 40 hydraulic pressure is applied. Thus, the tilt can be easily and fully accomplished in either direction since the piston 40 is centrally located in the cylinder member 48.

1 Description of the Embodiment of FIG. 3.

FIG. 3 illustrates another embodiment for the adjusting means 46 that is designed generally by the reference character 146. The adjusting means 146 forms part of a modified cylinder member 138.

As illustratedi the.adjusting means 146 has a second cylinder 160 formed in the cylinder member 138 and that is connected to the interior of the cylinder member 138 by a passageway 162. The passageway 162 receives a piston rod 164 which is connected at its other end witha piston 166 that is slidingly and sealingly located in the cylinder 160. A second piston rod 168 extends from the cylinder 160 and has its opposite end 170 arranged for connection to the pivot 52 located on the push arm 14.

Within the cylinder member 138 there is provided the passageway 172 that contains a valve 174 and a valve 176. Also provided in the cylinder member 138 is a vent valve 178 that is used during the filling of the cylinder 160.

The valve 174 is located between the passageway 162 and the cylinder 1601 and controls flow through the passageway 172. A seal 180 is in sliding and sealing engagement with the piston rod 164 prevents flow directly from the passageway 162 into the cylinder 160. With the valves 174 and 176 open, fluid can flow from the passageway 162 through the passageway 172 into the cylinder 160 on both sides of the piston 166.

Filling of the cylinder 160 from the cylinder member 138 can be accomplished when both valves 174 and 176 are open.

The passageway 172 includes a small branch passageway 182 which is connected with the cylinder 160 on the side of the piston 166 adjacent to the rod 164.

Thus. with the valve 174 closed and the valve 176 open.

fluid can flow from one side of the piston 166 to the -8other via the passageways 172 and 182.

Assuming that the cylinder member 138 is substituted for the tilt control means 36 and manual adjustment of the strut 20 by the operator accomplished as previously described, the valve 176 is left open and the adjusting means 146 automatically compensates for the length change. Thus. the blade 10 maintains a horizontal position and is pitched or pivoted about the pivots 16 and 18. Since the compensating change in length occurs by the movement of the piston 166 relative to the cylinder member 13 8, the piston 40 (illustrated in FIG. 2) can remain centrally located within the cylinder member 138. Thus, and at all times the maximum tilt of the blade 10 can be accomplished.

Once the pitch of the blade has been set, the valve 176 is closed and the piston 166 is then locked in position since fluid cannot flow from one side thereof to the other. Accordingly, if it is desired to then tilt the blade 10, pressure is again applied on the appropriate side of the piston 40 until the desired degree and direction of tilt is attained.

The detailed description hereinbefore provides for the desired tilting of the dozer blade in either direction, even though the blade may be pitched one way or the other. In the first embodiment, the adjustment of the strut containing the tilt cylinder is accomplished by means of a mechanical turnbuckle which is manually operated. In the second instancei the adjustment is accomplished by a simple hydraulic cylinder which allows the strut to change length as the operator adjusts the manual pitch strut. In both instances, full tilt of the blade is possible since the piston in the tilt cylinder remains centered.

Although not illustrated, it will be appreciated that various arrangements of adjusting means, such as turnbuckles and other devices capable of 1 -9changing or adjusting strut length# could be utilized in lieu of the particular turnbuckle illustrated.

It will be understood that the foregoing detailed description is presented by way of e xample only and that many changes and modifications can be made thereto without departing from the spirit or scope of the invention.

Claims

1. Improved tilting apparatus for dozer blades and the like including a blade that is supported by and pivotal relative to elongated first and second push arms on a dozer and an adjustable strut that has one end connected to the first push arm and the other end connected to said blade ahd includes a turnbuckle between the ends for changing the length of said strut to pivot the blade relative to the arms. the 10 improvement comprising:

is 1 c tilt control means adjustably extending between the second push arm and the blade and including a cylinder member having a hollow interior, said tilt control means including adjusting means connecting said cylinder member to said second arm, a piston movable in the interior of said cylinder memberi and a piston rod extending from said cylinder member and connected to said piston and blade, whereby said adjusting means is adjusted when the length of the strut Is changed to pivot said blade thereby maintaining said piston substantially centrally located in said cylinder member providing maximum tilt control for the blade.

2. The tilting apparatus of claim 1 wherein said adjusting means comprises manual adjustable turnbuckle means.

3. The tilting apparatus of claim 1 wherein said adjusting means comprises hydraulic adjustable means,

4. The tilting apparatus of claim 2 wherein said turnbuckle means comprises:

a first member having one end connected to the second push arm and having a threaded Zt 1. 1 1 1 end; threaded end on said cylinder member arranged end to end with the threaded end on said first member; and, turnbuckle member having threads mating with the thread on said first member and with the thread on said cylinder membert whereby rotation of said turnbuckle member moves said first member toward and away from said cylinder member.

5. The tilting apparatus of claim 3 wherein said hydraulic adjustable means comprises:

a second piston slidingly located in the interior of said cylinder member; a second piston rod having an end projecting from said cylinder member and having said projecting end connected to said second push arm; hydraulic fluid in said cylinder member on each side of said second piston; a passageway in said cylinder member connecting the hollow interior of said cylinder member on both sides of said second piston; and, valve means in said passageway for controlling flow therethrough, said valve means, when open, permits said piston to move displacing fluid from one side of said second piston to the other through said passageway and when closed prevents such flow preventing relative movement between said- second piston and cylinder member.

6. An improved method for providing maximum tilt to a dozer blade when said blade is pitched, the improved method comprising the steps of:

pitching the blade by manually adjusting the 1 h length oú a strut connecting the blade with a push arm on which the blade is pivotally mounted; changing the length of a first length control of tilt control means connecting the blade with a second push arm on which the blade i's also pivotally mounted to maintain the blade horizontal; and, actuating a hydraulic tilt control cylinder of said tilt control means to change the length of the tilt"control means to impose a twisting force on said blade causing said blade to tilt away from horizontal.

7. The method of claim 6 wherein the step of changing the length of the first length control includes the-step of manually rotating a turnbuckle which is part of the tilt control meansi whereby the length changes to match the length of said strut.

8. The method of claim 6 wherein the step o changing the length of the first length control includes the steps of:

opening a valve permitting hydraulic fluid to flow from one side of a piston to the other whereby said tilt control means changes length to match the adjusted length of said strut; and, closing said valve to prevent additional movement of said piston.

t -1 1 - 13

9. Tilting apparatus for dozer blades, substantially as hereinbefore described with reference to the accompanying drawing.

10. A method for providing maximum tilt to a dozer blade, substantially as hereinbefore described with reference to the accompanying drawing.

Published 1988 at The Patent Ofice. Sae Hz-use. W71 High Holborn. London WC1R 4TP. Firther copies may be obtained frorn The Patent Office, qlpq Branch- St MaIn' Crav. OrDirr;,or,. Kent BR5 3RD Printed by MultiDlex tech-iuaues ltd. St Marv Crav. Kent Cor. i -A-