Disc harrow wheel lock-down with depth control adjustment structure

An apparatus for positively locking the wheels of a disc in transport and depth control positions. The disc harrow comprises a frame having disc sections thereto. A transversely extending axle is secured to the frame and has ground engaging wheels at the opposite ends thereof which control the discing depth and transport height. A hydraulic cylinder is secured at its forward base end to the frame and has the rearward end of its cylinder rod pivotally connected to the axle to raise and lower the wheels with respect to the frame. A spacer assembly slidably embraces the cylinder rod. A cylinder stroke lock assembly is pivotally connected, at its rearward end, to the rearward end of the cylinder rod for pivotal movement between a first horizontal position and a second upstanding position. The spacer assembly comprises a spacer tube and spacing washers. The spacing washers may be selectively moved with respect to the cylinder stroke lock assembly to permit depth control adjustment. The cylinder stroke lock assembly, when the spacer assembly is positioned rearwardly of the forward end of the lock assembly, permits the cylinder rod to freely slidably move inwardly into the hydraulic cylinder. The forward end of the cylinder stroke lock assembly is adapted to engage the spacer assembly to limit the inward movement of the cylinder rod into the cylinder when the cylinder stroke lock assembly is in its horizontal position.

BACKGROUND OF THE INVENTION 
Modern implements such as disc harrows or the like ordinarily comprise a 
wheeled frame means having the earth working implements mounted thereon. 
Ordinarily, a hydraulic cylinder pivotally connects the support wheels and 
the frame means so that the wheels may be moved relative to the frame 
means to move the frame means between transport and field conditions. 
In most conventional implements, the cylinder rod of the cylinder is in an 
extended condition when the wheels are in their transport position. 
Considerable stress and strain is placed on the hydraulic system and its 
components as the implement is moved from one location to another. 
Additionally, there has not been any convenient and safe means for 
positively locking the cylinder in the "open" position to enable a person 
to work beneath the implement when required. Certain types of clamps have 
been employed for attachment to the cylinder rod itself but these devices 
are frequently lost, damage the cylinder rod and impose undue stress on 
the cylinder body. 
The ground engaging wheels are also used to control the discing depth and 
the prior implements do not have means for controlling the discing depth 
which may be conveniently changed. 
Therefore, it is a principal object of the invention to provide an 
implement wheel lock-down assembly. 
A still further object of the invention is to provide an implement wheel 
lock-down with depth adjustment control means. 
A still further object of the invention is to provide a disc wheel 
lock-down with depth control adjustment means. 
A still further object of the invention is to provide a cylinder stroke 
lock assembly. 
A still further object of the invention is to provide a cylinder stroke 
lock assembly including depth control adjustment means. 
A still further object of the invention is to provide a cylinder stroke 
lock assembly which does not impose undue strain on the cylinder. 
A still further object of the invention is to provide a cylinder stroke 
lock assembly which is economical to manufacture and durable in use. 
SUMMARY OF THE INVENTION 
A disc harrow comprising a frame means having a wheel assembly operatively 
mounted thereon for transport and discing depth control. A hydraulic 
cylinder is pivotally connected at its forward base end to the frame means 
and has the rearward end of its cylinder rod pivotally connected to the 
wheel assembly for moving the wheel assembly between transport and field 
positions. A spacer tube assembly comprising a spacer tube and spacing 
washers slidably embraces the cylinder rod. A cylinder stroke lock 
assembly is pivotally connected at its rearward end to the rearward end of 
the cylinder rod for movement between a first horizontal position and a 
second upstanding position. When the cylinder stroke lock assembly is in 
its horizontal position, and the spacer tube assembly is positioned 
rearwardly of the forward end of the stroke lock assembly, the cylinder 
rod may slidably move inwardly into the cylinder body. When the cylinder 
stroke lock assembly is in its horizontal position, and the spacer tube 
assembly is positioned forwardly of the forward end of the stroke lock 
assembly, the forward end of the assembly engages the spacer tube to limit 
the movement of the cylinder rod into the cylinder. The spacing washers 
may be selectively positioned relative to the forward end of the cylinder 
stroke lock assembly to provide a convenient depth control adjustment 
means.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The numeral 10 refers generally to a disc harrow generally comprising a 
frame means 12 having front and rear disc sections 14 and 16 secured 
thereto in an imposing manner as illustrated in FIG. 1. A hitch means 18 
is provided at the forward end of the disc harrow for connection to the 
prime mover. 
A rotatable tube 20 is operatively rotatably mounted to the frame means 12 
and has a pair of wheel support arms 22 and 24 extending downwardly from 
the opposite ends thereof. Wheels 26 and 28 are rotatably mounted on the 
lower ends of the wheel support arms 22 and 24 respectively. Arm 30 is 
secured to tube 20 and extends upwardly therefrom. The numeral 32 refers 
generally to a hydraulicly operated weight control apparatus which is 
disclosed in U.S. Pat. No. 3,809,165. 
The numeral 34 refers to a hydraulic cylinder having its base end 36 
pivotally connected to the frame means 12. Cylinder 34 is of the 
double-acting type and is provided with a cylinder rod 36 extending 
rearwardly therefrom. Rod 36 is provided with a clevis element 38 at its 
rearward or outer end which is pivotally connected to the upper end of the 
arm 39 by means of pin 40. Arm 39 is rigidly secured to tube 20 and 
extends upwardly therefrom as illustrated in the drawings. Cylinder 34 is 
provided with an impact plate 42 at its end 44 for a purpose to be 
described in more detail hereinafter. 
A cylinder stroke lock assembly 46 is operatively pivotally connected to 
the rearward end of the rod 36 by means of the support arms 48 and 50 
pivotally secured to the pin 40. Brace 52 is welded to arms 48 and 50 and 
extends therebetween adjacent the rearward ends thereof. Yoke 54 is welded 
to the forward ends of the arms 48 and 50 and is provided with an opening 
56 formed therein extending upwardly thereinto as illustrated in the 
drawings. Assembly 46 may be pivoted from the upstanding position 
illustrated in FIGS. 2 and 6 to the horizontal position illustrated in 
FIGS. 3, 4 and 7. 
Spacer assembly 58 slidably embraces rod 36 and is comprised of a spacer 
tube 50 and a plurality of spacing washers 62. As seen in the drawings, 
the spacing washers 62 are positioned adjacent the impact plate 42 with 
the tube 60 being positioned rearwardly thereof. 
When it is necessary to transport the disc from one location to another, 
the cylinder 34 is actuated by the tractor hydraulic system to cause the 
rod 36 to be completely extended therefrom which causes the wheels to 
pivotally move downwardly into ground engagement thereby raising the frame 
means 12 upwardly from the ground. The assembly 46 is first pivoted 
upwardly to the upstanding position of FIG. 2. The washers 62 and tube 60 
are then positioned adjacent the impact plate 42, forwardly of the 
assembly 46, and the assembly 46 pivotally moved downwardly from the 
upstanding position to the horizontal position so that opening 56 receives 
the rod 36. The hydraulic system is then operated to cause rod 36 to be 
slidably moved inwardly into the cylinder 34 until the yoke 54 engages the 
rearward end of the spacer tube 60 (FIG. 7) which limits any further 
inward movement of the rod. Thus, as the implement is moved from one field 
location to another, the hydraulic system does not absorb the shock which 
is normally created as the implement is moved over the road but the shocks 
are absorbed by the impact plate 42 and the strength of the cylinder 
itself and not on the seals, piston, etc. The cylinder stroke lock 
assembly 46 provides a positive lock for preventing the rod 36 from moving 
inwardly into the cylinder 34 so that the disc sections will not 
inadvertently lower as the implement is being moved from one location to 
another. Additionally, a person can work safely beneath the disc sections 
when the cylinder stroke lock assembly 46 is in the operative position 
since the apparatus provides a positive means for preventing the disc 
sections from moving downwardly. 
When it is desired to employ the disc and to control the discing depth 
thereof, the hydraulic cylinder 34 is initially actuated to cause the rod 
36 to be extended therefrom so that pressure between the yoke 54 and the 
tube 60 is removed. Assembly 46 is then pivotally moved upwardly 
sufficient to permit the tube 60 to be slidably moved rearwardly relative 
to the rod 36 so as to be positioned rearwardly of the yoke 54 (FIG. 3) 
when the assembly 46 is again moved to its horizontal position. After the 
tube 60 has been moved rearwardly on the rod 36, assembly 46 is pivoted to 
the horizontal position so that the yoke 54 will engage the spacer rings 
62 as the cylinder rod 36 is moved inwardly into the cylinder 34 thereby 
limiting the inward movement of the cylinder rod 36 to control the discing 
depth. Any number of the spacing washers 62 may be positioned rearwardly 
of forwardly of the yoke 54 to permit a convenient and quick adjustment of 
the discing depth. In other words, if all of the spacing washers 62 are 
positioned between the yoke 54 and the impact plate 42, the discing depth 
will be less than if only a portion of the spacing washers 62 are so 
positioned. 
Thus it can be seen that a novel disc wheel lock-down apparatus has been 
provided for positively locking the wheels in the transport position. It 
can also be seen that not only has a disc wheel lock-down apparatus been 
provided but a convenient depth control adjustment means has also been 
provided. It should be noted that while the invention has been described 
as being well suited for a disc harrow, it should be understood that the 
apparatus will also be ideally suited for all types of earth conditioning 
implements employing ground engaging wheels which are provided for 
transport and/or depth control purposes. Thus it can be seen that the 
apparatus accomplishes at least all of its stated objectives.