| 1. | A post foot, suitable for attachment to a post capable of being driven into the ground, the foot having a substantially right angled triangular wedge shape, the foot including connected first and second faces having a right angular relationship therebetween, and a third face connecting the first and second faces to form the hypotenuse of the triangle shape between the first and second faces, the foot further including two sides defined by the first, second and third faces, each side including a recess therein, each recess being separated by a central panel capable of receiving at least one securing device therethrough from the third face to the first or second face. |
| 2. | The post foot of claim 1 including at least one passage therethrough extending from the third face to the first or the second face via the central panel, the passage being capable of receiving the at least one securing device. |
| 3. | The post foot of claim 1 or 2 wherein the securing device is selected from nails or screws. |
| 4. | The post foot of any one of claims 1 to 3 wherein the portion of the recess which is at the top part of the recess, when the foot is in use, is provided with deflection means. |
| 5. | The post foot of claim 4 wherein the deflection means is an angled recess wall or one or more spines forming gussetting. |
| 6. | The post foot of any one of claims 1 to 5 wherein the foot is adapted to releasably retain at least one securing device on the foot for later use in securing the foot to a post. |
| 7. | A post foot formed from a plastics material and suitable for use with a post capable of being mechanically driven into position into the ground, the post foot having a substantially right angled triangular wedge shape, the foot including connected first and second faces having a right angular relationship therebetween, and a third face connecting the first and second faces to form the hypotenuse of the triangle shape between the first and second faces, each of the faces having two side edges and the foot further including two sides defined by the side edges of the first, second and third faces, each side including a recess therein, each recess having sides and a base, and each recess being separated by a central panel formed from the base of each recess, and wherein the foot is capable of receiving a securing device therethrough from the third face to the first or second face via the central panel, and also includes deflection means positioned in the recesses. |
| 8. | The post foot of claim 7 wherein the deflection means is an angled recess wall or, alternatively, at least one spine forming gussetting between the recess wall and the recess base. |
| 9. | The deflection means of claim 7 or 8 wherein the deflection means is positioned within the recess at a position adjacent the face of the foot which, when the foot is in use has a right angle relationship to the longitudinal axis of the post. |
| 10. | A kitofparts including the post foot of claim 1 or claim 7 plus at least one securing device. |
| 11. | A post foot substantially as herein described with particular reference to any one of the attached drawings. |
Background Art The use of a foot device to hold fence posts and strainer posts (herein"post") in place is well known within the fencing art.
Generally, a foot is nailed or wired onto the bottom part of a post prior to placing the post into a post hole which has been dug into the ground. The foot can be a variety of shapes but is usually a rectangular piece of wood which extends outwardly from the base of the post and about which earth is packed as the post hole is filled.
A post has to withstand various forces during its life cycle (i. e. such as vertical pull, angular pull, rotational pull, unbalanced pull and load bearing). If the post is not firmly held in the ground then, as a result of the various forces acting on the post and/or due to seasonal changes in the soil structure, the post can gradually loosen and cause fence failure.
When posts are mechanically driven into the ground, it is usually not possible to include a foot at the base of the post in order to assist in securing the post in position. This is because the action of driving a post into the ground will separate, or at least loosen, the traditional foot from the side of the post. To overcome the lack of a foot, such posts are normally driven further into the ground resulting in
the requirement of a longer post and/or additional features (such as another post or baton) to fix fence wires to.
The forming of a foot for use in the field is time intensive and there would be an advantage to be able to provide a foot for immediate use, produced in a cost effective manner.
Obiect of the Invention It is an object of the invention to overcome or ameliorate the problems associated with the prior art or at least to provide the public with a useful choice.
Summarv of the Invention In a first aspect the invention is a post foot, suitable for attachment to a post capable of being driven into the ground, the foot having a substantially right angled triangular wedge shape, the foot including connected first and second faces having a right angular relationship therebetween, and a third face connecting the first and second faces to form the hypotenuse of the triangle shape between the first and second faces, the foot further including two sides defined by the first, second and third faces, each side including a recess therein, each recess being separated by a central panel capable of receiving at least one device therethrough from the third face to the first or second face.
Preferably the securing device is selected from nails, screws, or similar devices.
Preferably the foot includes at least one passage therethrough extending from the third face to the first or the second face, via the
central panel, the passage being capable of receiving the securing device.
Preferably the foot is constructed of a plastics material.
Preferably the portion of the recess which, is at the top part of the recess when the foot is in use, is provided with deflection means.
Preferably the deflection means is an angled recess wall or one or more spines forming gussetting.
Preferably the foot is adapted to releasably retain at least one securing device on the foot for later use in securing the foot to a post.
Preferably the foot includes at least two slots in the first or second face of the foot adapted to releasably retain the securing device therein.
Preferably the securing device is releasably retained in at least one of the recesses.
Preferably the foot includes at least two securing devices releasably attached to the foot for later use in securing the foot to a post.
In a second aspect the invention is a post foot formed from a plastics material and suitable for use with a post capable of being mechanically driven into position into the ground, the post foot having a substantially right angled triangular wedge shape, the foot including connected first and second faces having a right angular relationship therebetween, and a third face connecting the first and second faces to form the hypotenuse of the triangle shape between the first and second faces, each of the faces having two side edges and the foot
further including two sides defined by the side edges of the first, second and third faces, each side including a recess therein, each recess having sides and a base, and each recess being separated by a central panel formed from the base of each recess, and wherein the foot is capable of receiving a securing device therethrough from the third face to the first or second face via the central panel, and also includes deflection means positioned in the recesses.
Preferably the deflection means is an angled recess wall or, alternatively, at least one spine forming gussetting between the recess wall and the recess base.
Preferably the deflection means is positioned within the recess at a position adjacent the face of the foot which, when the foot is in use, has a right angle relationship to the longitudinal axis of the post.
In a third aspect the invention is a kit-of-parts including a post foot according to the first or second aspect of the invention together with securing means.
Drawings The invention will be described including a preferred form thereof with reference to the following Figures. In the Figures: Figure 1: shows one preferred form of the invention; Figure 2: shows a side view of the preferred form of the invention of Figure 1 including passages indicated in phantom outline ;
Figure 3: shows a schematic diagram of the attachment of the invention as shown in Figures 1 or 2 to a post in use; and Figure 4 : shows a perspective view of second preferred form of the invention.
Figure 5 : shows a perspective view of a third preferred form of the invention.
Detailed Description of the Invention The invention broadly relates to a foot device which can be attached to a post to secure the post in position when the post is in place in the ground. Posts requiring such additional securing means are generally used for fencing for livestock control and pasture management but could be used in a variety of other situations as desired.
The foot device according to the present invention was developed generally to improve the securing of four main fence post types.
(i) Foot post: A post used in the lower ground of a fence line which must be capable of withstanding a vertical pull upwards, due to the elevated position of the posts on either side of the foot post. The foot device must be abie to assist in resisting this vertical upwards pull.
(ii) Angie post: A strainer post used where a fence line changes direction. The foot device must be able to assist in resisting the rotational forces created by the fence wires pulling around the angle.
(iii) Gate post: A large strainer post, on which a gate is swung. The foot device must be able to assist in overcoming the rotational forces that are caused by the binding of gate hinges to the gudgeons.
(iv) End post: A strainer post used on either end of a length of fencing. The foot device must be capable of assisting in withstanding the unbalanced rotational pull of the off centre fence wires attached to the end post.
The foot device of the present invention also being capable of achieving the benefits as described in (i) to (iv) above for a mechanically driven post as well as for a post which is placed within a post hole.
It is commercially desirable that the foot device of the present invention can be efficiently mass produced while remaining capable of retaining its integrity during mechanical driving. Thus a balance needs to be found between cost effective manufacture, product strength, and product design. It is therefore preferred that the foot is formed of a suitable plastics material as plastics materials are particularly suited to mass production of articles generally as will be well known. A large cost in the manufacture of such products from plastics materials, or other material such as steel and the like, is, however, the material cost itself.
The foot device of the present invention essentially comprises a triangular shaped wedge which is adapted to be attached to the bottom portion of a post before the post is either piaced in a pre-dug post hole or before the post is mechanically driven into the ground using a standard post-hole driver as will be known in the art.
With reference to Figure 1, one preferred form of the foot device of the present invention is shown. The foot 1 is of a generally triangular wedge shape having a top face 2, a back face 3, an angled front face 4 (obscured in Figure 1), and two triangular shaped sides 5 and 6 (side 6 obscured in Figure 1). As can clearly be seen, the sides 5,6 are defined by the side edges of the faces 2,3,4.
The foot 1 is generally shaped as a right angle triangle. The front face 4 being the hypotenuse of the right angle triangle. When the foot 1 is in place, the top face 2 extends substantially at a right angle from the side of the post to which the foot 1 is attached and thus assists the post in withstanding a vertical upwards pull, the sides 5,6 assist in resisting rotational pressures, and the angle of the face 4 assists in allowing the post plus the foot to be driven into the ground.
The right angle relationship of face 2 to a post (not shown in Figure 1) can best be seen with reference to Figure 3.
The foot 1, includes nail holes 7 and nail storage slots 8. The holes 7 and slots 8 are optional but preferred features of the invention.
The slots 8 are provided in order that nails (not shown in Figure 1) or other securing means, such as screws, rivets or the like as will be known in the art, can be releasably included with the foot 1 at the point of sale. The slots 8 could be replace by catches, or the like, situated within the recesses 9 in the sides 5,6, which are adapted to releasably retain the nails for later use. Thus nails of suitable length can be provided to the user for use when attaching the foot to a post.
The combination of the foot 1, plus nails, or other desired securing means, which would preferably be releasably attached to the foot 1, can be seen to be a kit-of-parts able to be sold as a unit to a user.
The holes 7 are preferably provided to allow ease of attachment of the foot 1 to the post (not shown in Figure 1). The holes 7 could be drilled by known means through the foot 1 but will preferably be
moulded in situ during production of the foot 1. The angular relationship of the holes 7 is best seen in Figure 2 which shows the holes 7 in phantom outline within the foot 1. The holes 7 extend through the foot 1 substantially at right angles to the front face 4 of post 1. The nails (not shown) are driven through holes 7 in direction of arrow"A"and into the post (not shown) which will be situated against the back 3 of foot 1. The right angular relationship of the face 4 and the nail holes 7 is not essential but is highly preferred as this will ensure effective securement of the foot 1 to the post (not shown) especially when the post is driven into the ground. The force of the ground against the face 4 will have the effect of driving the nails more firmly into the post (not shown) and the angular relationship of the nails to face 4 lessens the shear effect on the nails while maintaining ease of attachment.
Referring again to Figure 1, the sides 5 and 6 of foot 1 include a recess 9. The recess 9 in Figure 1 includes a bottom 10 formed from the outer face of the central portion of the foot 1 through which the nail holes 7 pass. This central portion is in effect defined by the bottom 10 of each recess 9 in sides 5,6. The central portion effectively connects the faces 2,3 and 4 and provides the integral support for the foot 1. The presence of the central portion allows nails to pass through the foot 1 to secure the foot 1 to a post (not shown).
As shown in Figure 1 the thickness of the central portion is sufficient to accommodate the diameter of nail hole 7 but this is not essential as can best be seen with reference to Figure 5.
The recess 9 as shown in Figure 1 and 4 preferably takes a generally triangular form, following the general shape of the foot 1, however this shape is not essential to the working of the invention.
The recess 9 in Figure 1 has walls 11 and includes deflection means provided by an angled top wall 11 a which will allow the foot 1, when mechanically driven into the ground in conjunction with a post (not
shown), to deflect obstacles which might otherwise impede the progress of the post plus foot by catching within the recess 9. If the recess 9 took a shape other than the generally triangular shape as shown in Figure 1, the equivalent top wall 11 a of that alternative shape should also be angled in a substantially similar manner to that shown for angled top wall 11 a. The angled deflection means is positioned at the part of the recess 9 which lies adjacent the face of the foot 1 which, in use, will form the top face of the foot 1. In Figures 1 and 4 this is indicated by face 2. The specific angle of the angled top wall (e. g. 1 1 a) of the recess is not particularly important but should be such to be able to deflect obstacles as will be readily apparent to a skilled person. As will be readily apparent the whole of the walls 11 of the recess 9 could include such an angled face structure if desired.
The recess 9 is provided in the foot 1 in order to lower the weight of the foot while, at the same time, reducing the amount of material, and hence the production cost, of the foot, while, with the retention of the central portion defined by the bottom 10 of the recess 9, maintaining sufficient structural strength and integrity to withstand the impact of a mechanical post driver. A further advantage of the provision of a recess such as shown at 9 in Figure 1, is to increase the ability of the foot to secure the post in the ground. When in place, the recess will have packed into it the earth which surrounds the foot.
This will have the effect of slightly improving the securing ability of the foot.
Alternative constructions and features may include, with reference to Figure 1, the inclusion of a further recess in the top face 2 to further reduce the weight and lessen material used in the construction of the foot 1. The area between the leading edge 24 and the recess 9 could include honey combing and/or could end in a "chisel"point with a second angle being created in the angled face 4
such that the length of the foot 1 from top part 2 to edge 24 is shortened.
An alternative construction may include, with reference to Figure 4, the use of gussetting formed by spines 30, in place of the angled top wall (11a of Figure 1), to deflect obstacles which may otherwise impede the progress of the post plus foot by catching within the recess 9. The use of spines 30 is preferred as this results in less material being used in the manufacture of the foot while retaining the advantages of the presence of deflection means to deflect material from the recess 9 when the foot 1 (plus post) is driven into the ground.
With reference to Figure 5, there is shown a perspective view of a further alternative construction of the foot 1. The perspective view is from one side only and the other side is essentially the same with the exception of the grooves 36 as will be explained further below.
The foot 1, in Figure 5, shows the presence of gussetting formed by spines 30 at the part of recess 9 adjacent the face 2 which would form the top face of the foot 1 when in use (as best seen in Figure 3). The spines 30 take the same triangular shape as the spines 30 shown in Figure 4 and includes angled face 30a to deflect obstructions when the foot 1 is being driven into the ground.
The foot 1 as shown in Figure 5 also includes a half round protrusion 35 in the bottom 10 of recess 9. The protrusion 35 defines substantially one half of the outer circumferential edge of the nail holes 7 passing through the foot 1 from face 3 to face 4. The other half being present in the bottom of the recess 9 obscured in Figure 5.
Nails (not shown) or the like will be driven through the central portion of the foot defined by the bottom 10 of the recesses 9, via the nail
holes 7. This protrusion 35, is a result of minimising the thickness of the central portion of the foot to a thickness less than the diameter of the nail holes required to house the nails when the foot 1 is in place on a post. This can best be seen by comparing the foot 1 shown in any one Figures 1 to 4 with that shown in Figure 5.
The foot 1 in Figure 5 also includes grooves 36 in face 3. The grooves 36 extend from the one edge of face 3 shown in Figure 5 to the nail holes 7 in face 3 obscured in Figure 5. Similar grooves 36 do not occur on the side of the foot 1 obscured in Figure 5. The grooves 36 are created by the"slot and short hole"method of creating the nail holes 7. There are other methods of forming the nail holes 7 but, by using this method, the tool for use in forming the product by injection moulding (or other suitable process) can be manufactured at lower cost and a reduction in the cycle time for forming the product may be achieved.
With reference to Figure 3, there is shown a schematic diagram of the attachment of a foot 1 to a post 20. The post 20 includes a cut out 21 which can be either provided in the post 20 or can be cut out of the post 20 by the user before attachment of the foot 1.
The nails 22,23 have been removed from the nail slots 8 and are driven through holes 7 into the post 20 once the foot 1 is in place within the cut out 21 in the post 20. In the preferred form shown in Figure 3, the nails 22,23 are of different lengths which will reflect the different distances the nails must travel to pass through the foot 1 and into the post 20. Preferably, nail 22 is longer than nail 23. It is also preferred that the nail 22 will be approximately 150mm long while the nail 23 will be approximately 100mm long. The preferred nail size is however 6mm diameter. Alternative sizes and lengths of nail as will be known to a skilled person in this art may also be used dependant on the size of the foot 1, thus these lengths are not intended to be
limiting. As will also be readily apparent to a person skilled in this particular art, the naits could simply be of identical length and need not be provided with the foot 1. In such a case the slots 8 would not need to be provided in the foot 1.
The foot is preferably constructed of a polymer (or plastics) material such as, for example, a low density polyethylene (LDPE) or a high density polyethylene (HDPE). The LDPE or HDPE could, if desired, be a re-granulated polymer conveniently produced via the re- pelletisation of scrap (waste) material. As will be known to a skilled person new material could also be used. The material selected can be any material known in the art however, if the foot plus post is to be driven into the ground, the material should be able to withstand the impact energy of a mechanical post driver which is calculated, by way of example only, as follows for a standard mechanical fence post driver using a weight of 204.5kg with a 1.8m drop.
Potential energy of mass before impact PE = Mgh = 204.5 x 9.81 x 1.8 3611 joules Kinetic energy absorbed by the post at impact KE = Mv2/2 And v = 42gh Therefore KE = 3611 joules If the foot plus post is to be simply placed in a pre-dug post- hole then the foot could be constructed of any suitable material as will be known to a skilled person, however it is preferred that a plastics material suitable for use with mechanical driving devices be employed to enable use in either situation.
In use, and with reference to Figure 3, the user of the foot 1 will place the foot 1 within the recess 21 in the post 20 ensuring that the leading edge 24 of the foot 1 is flush with or above the bottom face 25 of the post 20. This is to ensure the foot 1 remains in place when driven into the ground. Face 2 thus has a right angle relationship with the post 20, with respect to the general longitudinal axis of the post 20, and forms the top face of the foot 1. The nails 22,23 will then be driven through the nail holes 7 in foot 1, using a hammer or similar tool, into the post 20 thus securing the foot 1 to the post 20. As will be readily apparent the nails 22,23 could be replace by screws or any other suitable attachment device which is known to a skilled person.
The post 20, including a foot 1 on either side, may then be driven into the ground by known means with the nails 22,23 being further compacted into the strainer post 20 by the ground and the action of the post driver. In the alternative, the post 20 including a foot 1 on either side of the post 20, may simply be placed into a pre- dug post hole with the earth being compacted around the base of the post 20 and over the foot 1.
As will also be apparent, two or more feet may be used as desired. For example three or four feet could be attached for additional security if so needed.
The foot according to the invention, when made in its preferred form of a plastics material, will be produced using standard plastics moulding techniques such as injection moulding. The reduction in material used to construct the foot which have been referred to herein would then not only have the advantage of a lowered material cost but would also have the advantage of shortening the cooling time of the
initially formed product thus decreasing the cycle time and increasing the efficiency of the production process.
As will be readily apparent a variety of materials could be used to manufacture the post foot according to the invention. The use of plastics materials such as LDPE, HDPE, homopolymer polypropylene and the like is preferred due to the ability such materials to the incorporated into an efficient production process and the ability to withstand both post ramming impact and material deterioration when in place. The plastics material can also include strengthening agents if desired, such as nylon and carbon. There is also the possibility of constructing the post foot out of a metal material, such as steel for example, if desired. Metals are more expensive, generally than plastics, but can be manufactured by mass production methods. The cost of a post foot made from metal can be reduced in a similar manner to plastics materials (by using less metal). Similar problems will result from a strength perspective using a construction according to the invention the cost is lowered while minimising the ability of the foot to withstand the stresses inherent in ramming a post plus post foot into position. This may be utilised if the post is also metal (e. g. a pipe) and, in such a circumstance, the post foot could be welded on.
As will be apparent, in such a case a portion of the pipe would need to be flattened to receive the foot or the foot would need to be appropriately formed while possible, such a use it not preferred.
Example 1 The material used to construct the foot according to the present invention, and as used in the Trials below, is a Low Density Polyethylene (LDPE). The material properties are: Material Properties 1 Density 0.92 g/cm2
2 Water absorption 0.05%/24h/23°C 3 Tensile Strength 22 N/mm2 4 Impact Strength no break. KJ/m2 (Test b ASTM 624) 5 Ball indentation Hardness 39 N/mm2 6 Melt Temperature 105°C TrialResults Numerous field trials were carried out on the prototype Low- Density Polyethylene (LDPE) post foot. These tests involved mechanically ramming posts into the ground using a standard mechanical post rammer and were a comparison of a post plus a post foot as described above and a normal post without a foot for structure and property retention following ramming and resistance to pull-out. No Soil Type Normal Post (kg) Test Post (kg) 1 Alluvial 464 1556 2 Waiotira Clay 496 1406 Compacted Tanker 3-1726 Track As can be seen, the test foot according to the invention substantially improves the security of a driven post in the ground. The resistance levels to pull out of the test post following ramming is substantially higher than that for a normal post without a foot and clearly indicates that the integrity of the foot is retained to a sufficient extent to improve the security of the driven post when in place.
Example 2 The following is an example of the conditions used in a method of producing a post foot according to the invention utilising High
Density Polyethylene and standard injection moulding techniques as would be known to a skilled person.
Material: High Density Polyethylene ME 5000 Supplier: Cariant Colour: Black Temperature: Nozzle 180°C 1 180°C 2 180°C 3 180°C Clamp closing speed: Medium Clamp opening speed: Medium Ejection: Central Cooling: Fixed Full Cold Moving Full Cold Injection Speed: Slow Shot Weight: 131 gms (2 cavity) Max. Injection pressure: 700 psi Hold pressures: 15t stage 700 psi 12 sec 2"d stage 500 psi Cooling time: 35 secs Post Mould: Soak in water bath High Density Polyethylene: It is important for cycle times to keep the die as cool as possible during production.
Other adjustments such as"gate sizes"are adjusted to reach optimum fill time for moulding. Care should be taken to achieve a
good quality moulding with acceptable surface finish and good orientation of melt flow. A visual check should be completed for quality and the omission of occlusions or windows.
The invention has been described including reference to preferred forms thereof. Alterations or modifications as will be readily apparent to a person skilled in this particular art are intended to be included within the spirit and scope of the invention disclosed and as defined in the attached claims.