Patent Publication Number: US-7594782-B2

Title: Integral retaining foot for rammed post or pole

Description:
BACKGROUND 
   It is good fencing practice to fit a retaining Foot to key posts when erecting a fence. This would include the strainer post at each end of the proposed fence, angle post where there is a change in direction along the fence line and on those intermediate posts which are deemed at risk. 
   The task of the Foot is to prevent the post lifting out of the ground when tension is applied as in the case of a high tensile wire fence such as those used on the majority of New Zealand farms for stock management. 
   The foot can be made out of a variety of materials and is secured to the lower part of the post in such a way as to protrude into the surrounding ground so that when the hole dug for the post is rammed up the Foot is a major obstruction to the movement of the post. This has been the practice in those fences where the posts have been individually dug in. 
   There is a growing trend to use a post ramming machine to speed up the fencing task. These post rammers preclude the use of the traditional foot system and a variety of innovative solutions are being used to apply a Foot to a post after ramming. 
   All of these solutions require supplementary work on the post in question to implant the Foot substitute. 
   The rammed post approach to post erection needs a foot solution that is integrated with the ramming operation. 
   The same issues apply when ramming a post or pole for a construction project. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows the steel plate prior to pressing with the forming lines marked. 
       FIG. 2  is a perspective view of the plate after forming, showing the square center base  2 A, the angled side panels  2 B and the tapered arrow shaped fins  2 C at each of the four corners; also the mounting holes  2 D. 
       FIG. 3  the base of the post has been trimmed using a chain saw, firstly to cut the base square  3 A and then to cut the four angle faces  3 B to correspond with the side panels of the steel pressing. 
       FIG. 4  the steel pressed foot has been positioned on the base of the post and is ready for nailing up through the punched holes  4 A. 
   

   DESCRIPTION OF INVENTION 
   The Integral Retaining Foot for a Rammed Post or Pole is a pressed steel unit formed from a square of medium gauge galvanized steel ( FIG. 1  shows the flat steel plate prior to folding with the fold lines marked) that attaches to the base of the post or pole after first preparing the base to receive it. 
   In the forming process the square of steel plate is pressed into a deep three dimensional shape resembling an arrow head with four barbs but with a flat point. The steel is not stretched in the process but creased into shape and therefore maintains its full thickness throughout. ( FIG. 2  perspective view of the plate after folding showing the square base  2 A, the tapered sidewalls  2 B and the dart shaped fins  2 C at each of four corners). 
   A number of mounting points for nailing the foot to the post are also punched into the plate ( 2 D). 
   The base of the post or pole must be prepared to receive this unit. 
   Firstly the post must be trimmed square. Then four cuts with a chain saw are made to match the angles of the plate (see  FIG. 3 ). This ensures that all angles of the plate are securely supported by the post. The plate is then fitted to the post by skew nailing up using a very heavy gauge brad nail (see  FIG. 4 ). 
   The post or pole now with the Integral Retaining Foot in position is placed directly under the ramming machine and driven down to the required depth. 
   As the post moves down through the soil structure the narrower entry provided by the tapered square will force the ground to accept the post more rapidly and compress the displaced material to the side to impinge on the main body of the post. 
   The protruding arrowhead fins on each corner will penetrate the soil smoothly and on reaching the required depth allow the displaced material to return to occupy the space displaced by the fins during their downward movement. 
   The fins will now act as an anchor with the open top of the fin absorbing material previously displaced and locking the base of the post in the ground. 
   In addition to preventing upward movement the fins will also eliminate horizontal rotation of the post. 
   The Integral Retaining Foot for a rammed post therefore fulfills both tasks previously undertaken by the traditional dug in post and foot systems and allows the wider use of ramming with confidence using the new foot system described in this invention. 
   It will be appreciated that the invention consists in the parts, elements and features described in this specification, and is deemed to include any equivalents known in the art which, if substituted for the described integers, would not materially alter the substance of the invention.