Adjustable height wagon

An adjustable height wagon capable of being manipulated between an orientation allowing maximum lift and an orientation allowing maximum height. The provision of a lift mechanism below an undercarriage of the wagon increases the stability of the wagon during lifting, and allows a material supporting bed to be drawn into contact with the undercarriage, thereby increasing the stability of both the material supporting bed and the wagon.

BACKGROUND OF THE INVENTION 
The present invention relates generally to an adjustable height wagon and, 
more particularly, to a scissors-type wagon which may alternatively be set 
for low, high-power lifting or for high, low-power lifting. 
Adjustable height wagons are well-known in the prior art and lave been 
adapted to agricultural use for centuries. The lifting mechanism of most 
prior art adjustable height wagons is very heavy and tends to unbalance 
the wagon as the lifting bed is raised or the wagon is drawn around 
corners. The use of a lifting device which adds to, rather than detracts 
from, the stability of the wagon is accordingly desirable. 
An additional problem associated with prior art adjustable height wagons is 
the inability to provide a wagon which is possessed with a heavy lifting 
capability as well as a high lifting capability. Adjustable height wagons 
are available with a large weight lifting capability, but these types of 
wagons typically do not have a high lifting capability. Similarly, 
adjustable height wagons are available with desirable height 
characteristics, but these wagons are underpowered for heavy lifting. It 
is accordingly desirable to provide an adjustable height wagon capable of 
alternately accommodating heavy lifting jobs and high lifting jobs. 
Difficulties encountered in the prior art discussed hereinabove are 
substantially eliminated by the present invention. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
adjustable height wagon for lifting large loads. 
A further object of the present invention is to provide an adjustable 
height wagon for lifting articles requiring a high vertical lift. 
Another object of the present invention is to provide an adjustable height 
wagon having stable lifting attributes. 
Still another object of the present invention is to provide an adjustable 
height wagon which maintains stability as it moves over the ground. 
Other objects of the present invention will become apparent upon reference 
to the following specification, drawings, and claims. 
By the present invention, it is proposed to overcome difficulties 
encountered heretofore. To this end, an adjustable height wagon is 
provided for transporting and lifting material. The wagon is provided with 
a substantially horizontal upper portion capable of fully collapsing 
toward a lower portion of the adjustable height wagon for stability of the 
substantially horizontal upper portion of the adjustable height wagon 
during transportation of the material. 
A material supporting bed is provided and is capable of being positioned in 
a substantially horizontal position for support and transport of material. 
An undercarriage capable of supporting the material supporting bed during 
operation transportation and storage of the adjustable height wagon is 
also provided. The adjustable height wagon has a first arm having a first 
end, a second end, and a center portion, wherein the first end of the 
first arm is operably and pivotally secured to the undercarriage and 
wherein the second end of the first arm is operably and slidably coupled 
to the material supporting bed in supporting engagement thereof. 
The adjustable height wagon has a second arm having a first end, a second 
end, and a center portion, wherein the first end of the second arm is 
operably and pivotally secured to the material supporting bed for 
supporting engagement thereof, the second end of the second arm is 
operably and slidably coupled to the undercarriage, and the center portion 
of the second arm is operably and pivotally connected to the center 
portion of the first arm. Operably connected to the second arm are means 
for moving the second end of the second arm relative to the first end of 
the first arm. 
Preferably, the adjustable height wagon is provided with means for 
adjusting tile operable and pivotal connection of the center portion of 
the second arm to the center portion of the first arm to manipulate the 
extension height and lifting capacity of the adjustable height wagon.

DETAILED DESCRIPTION OF THE INVENTION 
In the Figures, an adjustable height wagon 10 for lifting material is 
illustrated, wherein an undercarriage 12 is operably connected to a 
material supporting bed 14 by a first pair of arms 16 and a second pair of 
arms 18 (FIG. 1). The arms 16 and 18 are pivotally connected to one 
another and are moved in relationship to one another by a lift mechanism 
20 used to raise and lower the material supporting bed 14. 
FIG. 1 shows the adjustable height wagon 10 in an extended position with 
the material supporting bed 14 lifted well above the undercarriage 12. The 
first pair of arms 16 are pivotally secured to the undercarriage 12 as 
shown in FIG. 4. The undercarriage 12 is provided with a pair of tracks 
22. A pair of wheels 24 journaled to an arm support 26 ride within these 
tracks 22. The arm support 26 is secured to the second pair of arms 18 by 
weldments or similar securement means. 
Pivotally secured between the first pair of arms 16 and the second pair of 
arms 18 are a pair of hydraulic pistons 28 (FIG. 4). The pistons 28 are 
preferably located below the undercarriage 12 to lower the center of 
gravity of the adjustable height wagon 10. As shown in FIG. 5, the 
material supporting bed 14 is provided with a pair of tracks 30 to which 
the second pair of arms 18 is pivotally secured. Secured between the 
second pair of arms 18 is a brace 32 used to separate and support the 
second pair of arms 18. A similar brace 34 is secured between the first 
pair of arms 16. Additionally, a pair of wheels 36 are journaled to the 
ends of the brace 34. The wheels 36 are provided in the tracks 30 and move 
along the tracks 30 as the material supporting bed 14 is moved upward and 
downward. 
As shown in FIGS. 1 and 2, the first pair of arms 16 are pivotally 
connected to the second pair of arms 18 by a pair of pins 38. The first 
pair of arms 16 are provided with upper holes 40 and lower holes 42 
designed to receive the pins 38 (FIGS. 1 and 2). Similarly, the second 
pair of arms 18 are provided with upper holes 44 and lower holes 46 for 
receipt of the pins 38. Preferably, the holes 40, 42, 44, and 46 are 
placed midway between the ends of the arms 16 and 18 and are located 
generally along a line perpendicular to the length of the arms 16 and 18. 
To operate the wagon 10, the pins 38 are placed either through the upper 
holes 40 and 44 of the first and second pairs of arms 16 and 18, or 
through the lower holes 42 and 46 (FIGS. 1-2). If it is desired to lift a 
heavy load a short distance, it is desirable to place tile pins 38 through 
the upper holes 40 and 44. By placing the pins 38 through the upper holes 
40 and 44, the point at which the first pair of arms 16 and second pair of 
arms 18 pivot in relationship to one another is lowered. By lowering the 
pivot point between the first pair of arms 16 and the second pair of arms 
18, the leverage of the two pairs of arms 16 and 18 is increased, thereby 
allowing the lift mechanism 20 to lift a heavier load placed upon the 
material supporting bed 14. 
If, it is desired to raise the material supporting bed 14 higher than the 
maximum point achievable with the pins 38 in the upper holes 40 and 44, 
the pins may be moved to the lower holes 42 and 46 (FIGS. 1-2). By moving 
the pins 38 in this manner, the pivot point between the first pair of arms 
16 and the second pair of arms 18 is raised. The maximum height achievable 
for the material supporting bed 14 in relationship to the undercarriage 12 
is thereby raised. By manipulating the pins 38, the wagon 10 may be set up 
for very high lifting or very heavy lifting, depending on the required 
task. 
By placing the lift mechanism 20 below the undercarriage 12, the arms 16 
and 18 have sufficient room to fully retract. The material supporting bed 
14, therefore, can then come into contact with the undercarriage 12 when 
retracted. The material supporting bed 14 is thereby supported by the 
undercarriage 12 which provides greater strength and a more stable support 
than that provided by the arms 16 and 18 alone. This added strength and 
stability aids in the support of heavy loads and in transportation of 
goods. The placement of the lift mechanism 20 below the undercarriage 12 
also adds stability to the entire wagon 10 in both the raised and lowered 
orientations of the wagon 10. The placement of the lift mechanism 10 
lowers the center of gravity of the wagon 10, not only affording the wagon 
10 stable lifting attributes, but also stabilizing the wagon 10 as it is 
pulled. 
The foregoing description and drawings merely explain and illustrate the 
invention and the invention is not limited thereto, except insofar as the 
claims are so limited, as those skilled in the art who have the disclosure 
before them will be able to make modifications and variations therein 
without departing from the scope of the invention. For example, it is 
contemplated that numerous holes may be placed along the first pair of 
arms 16 and second pair of arms 18 to vary the lifting capability of the 
wagon 10 over a broader range of heights and loads.