Portable pitching mound base

A portable pitching mound base has a network of structural elements with a flat bottom and generally circular periphery providing support for a cover which presents a flat top in the center and inclined sides sloping downward towards the periphery. The base is made in two halves with structural partitions at the dividing plane having access ports to allow lifting means such as a forklift, truck. The cover may be made of sheet material with metal mesh or with sheet aluminum having surrounding ridges to hold the overlying dirt of a pitcher's mound.

This invention relates to improvements for the design of playing field 
facilities. In particular, it relates to an improved design for a portable 
pitching mound base for baseball fields. 
Recreational playing fields, such as those found in Municipal parks;, are 
often used for a multitude of purposes such as football, soccer, lacrosse, 
track and field events, as well as baseball, softball, fastball, and the 
like. 
Most of these games are preferably played on flat relatively smooth grass 
or ground. Baseball, however, unlike other sports, and unlike related 
games, such as softball and fastball, is played on a "diamond" in which 
the pitcher's position is located on a "pitching mound" which is generally 
dome-shaped, roughly round or circular, raised area in the middle of the 
field. This mound, which is necessary to the proper playing of baseball, 
is inconvenient, dangerous and inappropriate for other games, including 
related games such as fastball and softball which may be played on a very 
similar diamond. 
Although it would be obvious to modify the field to suit the game, the 
placement of a dirt mound for baseball and its removal for other sports is 
a difficult, time-consuming, and expensive operation. 
It is therefore desirable to provide a pitching mound which may be placed 
in position on a baseball diamond and removed relatively easily. 
A single structure of this nature, because of its shape and lateral extent, 
is very awkward to handle and very heavy to lift. 
Several attempts have been made to create mounds of sectional interlocking 
pieces, but these often require elaborately constructed or moulded shapes 
so that the pieces will fit together without moving when they are covered 
by dirt or used by baseball players. A mound which is merely a dome-shaped 
structure is inadequate because a proper pitching mound is meant to be a 
dirt surface. Elaborately interlocking pieces are difficult to use in 
connection with a dirt surface because the connecting surface has become 
impregnated with dirt and do not fit well. 
Other designs which are composed of a series of interlocking pieces of 
manageable weight are subject to being unlawfully removed and replacement 
pieces are difficult to obtain. 
For these and other reasons the present invention is designed to provide a 
portable, removable, pitcher's mound base which may be installed on a 
baseball diamond and removed with relative ease. The design is also 
intended to provide a pitcher's mound base which is relatively sturdy, can 
be covered with dirt, and is difficult to remove by unauthorized persons. 
These objects and other advantages are sought to be achieved by the present 
invention which provides a portable base for a pitcher's mound comprising 
a pattern of structural elements having a flat bottom plane and a 
generally circular circumference and a covering supported by this 
structural element capable of supporting a layer of dirt, said cover 
presenting a generally level top in the centre and having inclined sides 
sloping downwards towards the bottom plane at the circumference. 
Preferably, the base is constructed in two parts along a vertical plane 
from side to side with a structural partition in each part adjacent the 
dividing plane. Ideally, each structural partition has access openings to 
receive lifting means such as the tynes of a forklift truck. The cover may 
be constructed of sheet material with a metal mesh fabric or may be 
covered with sheet aluminum having a pattern of ridges around the inclined 
sides so as to hold the overlying dirt in position.

In the embodiment illustrated in FIG. 1, the outer periphery of the mound 
(meaning the dirt surface) is represented by a circle 2 and the 
circumference of the underlying base beneath the dirt is represented by 
the circle 4. The top of the mound bas a generally flat area 6 in the 
centre with a pitcher's "rubber" 8 located thereon. 
In FIG. 2 the same mound and base are illustrated but the arrow 10 
represents the orientation and direction towards home plate of a baseball 
diamond. In addition, the location of cross-sectional views discussed 
later are indicated. Although the invention is not restricted to specific 
dimensions, it is intended that the preferred embodiments will conform 
with the standards which are generally used or prescribed by baseball 
rules. 
In FIG. 2 it can be seen that near the centre of the mound is a pitcher's 
rubber 8 approximately 24 inches.times.6 inches. The overall mound has a 
radius of about 9 feet (or diameter of 18 feet). The flat portion 6 at the 
top is approximately 5 feet across and 3 feet 4 inches in depth (in the 
pitcher's direction). 
In FIG. 3 the substructure or base of the mound is illustrated with the 
location of the structural elements such as 12 shown. FIG. 4 illustrates 
an example of the strut 12 which may be made out of metal, plastic, or 
wood, or such other structural material, and may have holes in the struts 
to make them lighter. 
Also illustrated in FIG. 3 is a dividing line 14 which separates the front 
portion of the base A which slopes towards home plate from the rear 
portion B which slopes towards the out field. Thus, the base for the 
pitcher's mound is constructed in two parts as described, and for reasons 
explained later. 
Also illustrated in FIG. 3 is a series of circular, concentric rings 31 
composed of upstanding ridges of barriers illustrated in the cross-section 
of FIG. 4. These ridges provide restraint to hold the soil which is 
subsequently used to cover the base and helps to maintain it in position 
and prevent it from sliding down the slope. 
FIG. 5 is a vertical elevation view, from the rear, of the forward portion 
A at the line 14 in FIG. 2. In this view the rear wall or partition of the 
front section A is shown at 16 with the flat top portion 6 surmounted by 
the pitching rubber 8 and having inclined side surfaces 18 which terminate 
against brief upstanding perimeter wall 20. The whole section has a floor 
22 underlying the entire substructure. 
Furthermore, the rear wall 16 has a pair of openings 24 which represent the 
opening of a pair of tunnels 26 adapted to receive the tynes of a forklift 
truck which may be used to lift the section and move it about. 
FIG. 6 is a cross-sectional view along the lines 6--6 in FIG. 2 showing the 
floor 22 and the inclined sides 18 with the pitcher's rubber 8 on top of 
the horizontal portion 6. 
For illustrative purposes, the front portion A is shown separated from the 
rear portion B and in each portion the tunnels for receiving the tynes of 
a forklift truck are illustrated at 26 and 28 respectively. The dividing 
wall or partition of the rear portion B is illustrated at 30 and it will 
be understood that when the base is assembled, this will match and abut 
the dividing wall 16 of the front portion A. 
FIG. 7 illustrates the structure of the front portion A of the mound base. 
The structural struts 12 are illustrated by this exposed view. The 
covering is provided by a light aluminum sheet 32 which may be covered by 
a covering of plastic or similar material so that the structure of the 
base remains substantially hollow and the dirt of the pitcher's mound will 
be supported by the covering and overlay the entire base. 
It will be noted from the drawings referred to that the peripheral wall 20 
and the pitching rubber 8 are raised above their surroundings by 4 or 5 
inches, but it should be understood that once the dirt is spread over the 
base, the top of the pitching rubber will be approximately level with the 
surface of the dirt, and the peripheral wall 20 and all other parts of the 
base will be covered. 
In order to secure the two portions of the base in position, it may be 
desirable to drive stakes through the floor 22 into the ground beneath, or 
alternatively, to place stakes against the peripheral wall 20 at various 
locations around the perimeter. Alternatively, it may be desirable to 
provide the base with attached downwardly projecting spikes which will 
engage the ground whenever the base portions are put in place, but this 
would make it difficult to move the separated portions about to gain 
access to the tunnels designed to receive the forklift apparatus. 
It will be readily appreciated that a level playing field may be adapted 
for baseball by transporting the two segments of the base separately by 
means of a forklift truck and placing them in the desired position. 
Because the access points for the tynes of a forklift truck are located in 
the dividing wall, the bulk of the weight of each section will be located 
nearest to the forklift truck and will therefore ensure that the centre of 
gravity is well positioned, and that the base segment is well secured for 
transportation by a forklift truck. 
Of course, the two sections cannot be put in their assembled position 
because one portion would interfere with the access to the other portion 
but they can be placed in close proximity and easily moved by workers into 
the assembled position. The base can then be covered with the appropriate 
quantity of dirt to about a depth of approximately 4 or 5 inches to 
provide a pitcher's mound of the appropriate dimensions, configuration, 
and material for baseball. 
When the field is desired for other purposes, the dirt can be scraped off 
and the segment separated and moved in the similar manner. 
By virtue of this device most of the volume of a pitcher's mound is 
occupied by the base structure and all the weight and volume of dirt in a 
conventional pitcher's mound does not have to be removed. 
Although the covering described is sheet aluminum with ridges, it could be 
a sheet of other material such as plastic, wood, tarred paper etc., and 
might be covered with some non-slippery finish of wire mesh. 
It will, of course, be realized that numerous modifications and variations 
of the illustrated embodiment may be employed without departing from the 
inventive concept herein.