GB2486298A

GB2486298A - Hand tool for forming a hole in the ground surface

Info

Publication number: GB2486298A
Application number: GB1116849.9A
Authority: GB
Inventors: Robert Frederick Smith; Anthony Arthur Steele
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-12-16
Filing date: 2011-09-30
Publication date: 2012-06-13
Anticipated expiration: 2031-09-30
Also published as: GB2486298B; GB2486464A; WO2012080690A1; GB201116849D0; GB201021328D0

Abstract

The hand tool 10 includes a support body (11, Figure 3) which defines a collection chamber 25 for receiving ground material. An operating handle 13 extends from the support body for rotating the support body about a longitudinal axis 15 and advancing into the ground material. The support body includes first 17 and second 20 cutter assemblies. The first cutter assembly 17 has at least one blade 18 which extends inwards towards the longitudinal axis from the end 16 of the support body furthest from the operating handle. In use, rotation of the support body results in the or each blade cutting into the ground material and directing the ground material into the collection chamber. The second cutter assembly 20 has at least one blade 21 which extends outwards from the support body, in a direction away from the longitudinal axis, at a position aligned with an opening (24, Figure 3). Rotation of the support body results in the or each blade 21 cutting into the ground material which is thereby directed through the opening and into the collection chamber 25.

Description

I

HAND TOOL FOR FORMING A HOLE IN THE GROUND SURFACE

This invention relates to a hand tool for the removal of soil thereby to form a hole in the ground or to provide a soil sample. The invention relates in particular, though not exclusively, to a hand tool for forming in the ground a hole for the location of a post, such as a fence post, or for the planting of a plant, shrub or the like.

Various designs of hand tools have been proposed for the purpose of forming a generally cylindrical hole in the ground without the effort needed to use a simple implement such as a spade. However the hitherto known hand tools have suffered one or more disadvantages such as being difficult to force into the ground, being difficult to rotate against the natural resistance provided by surrounding soil and of having only a poor ability to facilitate removal of soil.

The present invention seeks to provide a hand tooi for forming a hole in the ground surface and in which at least some of the aforedescribed disadvantages of known hand tools are mitigated or overcome.

In accordance with the present invention there is provided a hand tool for forming a hole in the ground surface, said hand tool comprising a support body which defines at least in part a collection chamber for receiving ground material, said body being rotatable about a longitudinal axis thereof, and an operating handle extending from the support body for enabling the support body to be rotated and advanced into the ground material, said support body comprising first and second cutter assemblies, said first cutter assembly comprising at least one blade which extends inwards towards said longitudinal axis from that end of the support body furthest from the operating handle whereby, in use, rotation of the support body results in the or each said blade cutting into the ground material and entering the collection chamber, and said second cutter assembly comprising at least one blade which extend outwards from the support body, in a direction away from said longitudinal axis, at a position aligned with an opening whereby, in use, rotation of the support body results in the or each blade cutting into the ground material and being urged through said opening and into the collection chamber.

Preferably the second cutter assembly is positioned such that in use it directly directs cut ground material into the collection chamber at a position between the operating handle and first cutter assembly. Thus all or a substantial part of the second cutter assembly may lie closer to the operating handle than the first cutter assembly.

The support body may define said opening(s) through which, in use, cut material is directed from the second cutter assembly to the collection chamber.

Preferably the or each cutter blade of the second cutter assembly is inciined to that radial direction which extends between the blade cutting edge and said longitudinal direction such that, in use, cut material is positively directed inwards into the collection chamber.

Similarly it is preferred that the or each cutter blade of the first cutter assembly is inclined relative to a plane perpendicular to said longitudinal axis such that, in use, cut material is positively directed into the collection chamber.

The support body typically may be of a substantially cylindrical form though other cross-sectional shapes such as hexagonal shapes may be employed.

One or each of the first and second cutter assemblies may be substantially permanently secured to or be integral with the support body. Alternatively individual cutter blades or one or each of the cutter assemblies may be selectively removable, for example for ease of re-sharpening or for interchange with a cutter assembly of an alternative form more specifically suited to the type of ground material which is to be excavated. Thus, for example, in the case of a tool to be used to remove a relatively heavy material such as clay the or each cutter of the first cutter assembly may extend radially inwards by only a short distance so as not to present undue resistance to the subsequent removal of collected material from the collection chamber as compared with a first cutter assembly for use with relatively free flowing ground material, such as soil having a high sand content, and for which it is beneficial to provide a higher number of cutter blades and/or blades extending relatively further inwards so as better to retain cut material as the tool is removed from the hole.

The first cutter assembly typically may comprise the same number or fewer cutter blades than the second cutter assembly. Alternatively, however the first cutter assembly may comprise a greater number of blades.

A cutter blade of the first cutter assembly and a cutter blade of the second cutter assembly may be formed integrally with one another, and said integrally formed blades may be removably secured to the support body.

The collection chamber may be closed at one end, opposite the region of the support body that supports the cutter assemblies, but preferably is substantially open.

If the collection chamber is closed at one end the operating handle may be secured directly to the closure material. Otherwise it is envisaged that typically the handle will be supported by two or more struts that extend from the tubular support body to an end of the operating handle. Spaces between the struts thereby enable collected material to be removed readily by use of an implement pushed downwards between the struts and on to the collected material.

Although collected material may be removed by use of an implement inserted through an open end of a support body, the present invention further provides that the hand tool may comprise a soil release plate located within the chamber and which is free to move axially relative to the support body either by action of material entering the collection chamber or, for the removal of collected material, by an operator acting on a release rod to advance the plate in a direction downwards towards the cutter assemblies.

The soil release plate may be shaped and dimensioned to correspond closely with the internal cross-sectional profile of the collection chamber, in which case it will always be positioned axially inwards of the first cutter assembly.

Alternatively it may be relatively small such that when the hand tool is first positioned to rest on the ground surface, the soil release plate also lies directly on the ground surface. That is, the soil release plate may lie substantially aligned with and radialiy inwards of the cutter blade(s) of the first cutter assembly. As the hand tool is rotated and urged downwards into the ground the soil release plate will remain on the ground surface and by providing the release rod with graduated markings an operator is provided with an indication of the depth to which the cutters have been advanced.

The end of the soil release rod furthest from the release plate preferably is provided with an end stop which may engage with an end of the operating handle such that the soil release plate is prevented from moving axially outwards beyond the first cutter assembly.

The operating handle may comprise a single shaft or rod that extends longitudinally and co-axially with said longitudinal axis of rotation of the support body, and a cross-bar which enables the handle readily to be rotated.

The crossbar may be integral with the shaft or rod or may be pivotally secured thereto such that it may lie parallel with the shaft when not in use.

Alternatively the cross-bar may be a separate member which, for convenience of storage and transportation may, for example, be insertable in a connection socket secured to the shaft and having a through-bore to receive the crossbar.

A shaft or rod of the operating handle may be provided with a series of depth markings which in use indicate the depth of the excavated hole. The soil release rod also may be provided with markings to indicate the depth by which the hole has been deepened during a cutting operation.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:-Figure 1 is a longitudinal sectionai view of a hand tool in accordance with the present invention; Figure 2 is a cross-sectional view on the plane A-A of Figure 1: Figure 3 is a side view in the direction B of Figure 1: Figure 4 is a longitudinal sectional view showing the hand tool of Figure 1 in a position ready to deepen an existing hole, and Figure 5 is a view similar to that of Figure 4 but showing the hand tool with accumulated ground material ready for removal from a part-formed hole.

A hand tool 10 comprises a cylindrical support body 11 which is connected to the tubular shaft 12 of an operating handle 13 by means of a pair of struts 14.

The upper end of the handle 13 is provided with a crossbar 9 which is integral with the shaft 12 to enable the shaft 12 to be rotated about an axis co-axial with the longitudinal axis 15 of the cylindrical support body 11.

The lower end region 16 of the support body comprises a first cutter assembly 17 formed by four cutter blades 18 each individually riveted, bolted or otherwise secured to the support body. Each cutter blade 18 extends radially inwards from the support body and also in a downwards direction, away from the handle 13, so as to lie inclined at an angle of approximately 45° relative to the longitucflnal axis 15 of the support body, as best seen in Figure 1.

Each cutter blade 18 has a cutting edge 19 which extends in a substantially radial direction as viewed in Figure 2.

The lower end region 16 of the support body also provides support for a second cutter assembly 20 comprising four cutter blades 21 which extend radially outwardly from the support body. Each cutter blade is secured, in this case by rivets or bolts, to the support body and has a cutting edge 22 which extends parallel with said longitudinal axis 15 of the support body. Each cutter blade 21 extends outwards in a direction inclined to the circumference of the support body, as best viewed in Figure 2, and in this embodiment is inclined at approximately 45° to the circumferential direction. The inclined cutter blades define surfaces 23 which, when the tool is rotated in a clockwise direction C as viewed downwards in Figure 2, serves to direct ground material radially inwardly through a respective opening 24 provided in the lower end region 16 of the support body.

In use of the hand tool, on rotation in a clockwise direction as viewed in the plane of Figure 2, ground surface material is directed by the inclined blades of the first and second cutter assemblies to flow radially inwards from the second cutter assembly and axially upwards from the first cutter assembly into a collection chamber 25 defined by the space within the support body 11.

The shaft 12 of the operating handle is provided with a series of depth markings 29 (two only illustrated in Figures 1 and 2) which can be read against the level of the ground surface to indicate the depth of an excavated hole.

Although not an essential feature of a hand tool in accordance with the present invention, this embodiment of the invention is provided with the optional further feature of means for ejection of collected material from the collection chamber 25 and also for assessing the depth of excavation of ground material during a single cutting operation. For that purpose the hand tool is provided with a soil release rod 30 that is longitudinally slidable within the tubular shaft 12 and has secured to the lower end thereof a soil release plate 31.

The other end of the soil release rod 30 is provided with an end stop 32 which, prior to cutting of ground material, abuts the crossbar 9 and thereby ensures that the release plate 31 is prevented from dropping downwards axially beyond a position at which it is aligned with the cutting edges 19 of the blades 18.

Prior to a cutting operation the release plate 31 rests on the ground surface, or bottom of a part-formed hole in the manner shown in Figure 4. During rotation and downwards advancement of the hand tool the cut ground material which is directed into the collection chamber 25 and the plate 31 is forced to retract in a direction towards the crossbar 9 to a position such as that shown in Figure 5. In this position, with the collection chamber substantially wholly occupied by cut material, the soil release rod is forced upwards to lift the end stop 32 above the crossbar 9. A scale 33 marked on the release rod 30 accordingly is able to provide an indication of the depth through which the hand tool has been advanced during each of a series of cutting operations. A compression spring 34 is provided between the release plate 31 and end of the shaft 12 to ensure that at least following initial accumulation of the material in the chamber 25 the plate 31 is maintained in contact with the upper surface of accumulated material in the chamber.

In use, following removal of the hand tool from an excavated hole accumulated material may readily be forced from the collection chamber by applying downwards pressure to the end stop 32.

A particular feature of the outwardly extending cutters of the second cutter assembly 20 is that they result in formation of a hole which has a larger diameter than the external diameter of the support body, as best seen in Figures 4 and 5. Accordingly self-supporting ground material defining the cylindrical wall of the hoie is spaced from the outer surface of the support body such that the support body is free from contact with the surrounding ground material and thus does not contribute to the rotational resistance experienced during use of the tool. Furthermore that clearance readily enables a small adjustment of alignment of the tool and hole during excavation.

Claims

CLAIMS1. A hand tool for forming a hole in the ground surface, said hand tool comprising a support body which defines at least in part a collection chamber for receiving ground material, said body being rotatable about a longitudinal axis thereof, and an operating handle extending from the support body for enabling the support body to be rotated and advanced into the ground material, said support body comprising first and second cutter assemblies, said first cutter assembly comprising at least one blade which extends inwards towards said longitudinal axis from that end of the support body furthest from the operating handle whereby, in use, rotation of the support body results in the or each said blade cutting into the ground material and directing said ground material into the collection chamber, and said second cutter assembly comprising at least one blade which extends outwards from r the support body, in a direction away from said longitudinal axis, at a position aligned with an opening whereby, in use, rotation of the support body results in the or each blade cutting into the ground material and directing said ground C material through said opening and into the collection chamber.
2. A hand tool according to claim 1 wherein the second cutter assembly is positioned such that, in use, it directly directs cut material into the collection chamber.
3. A hand tool according to claim 1 or claim 2 wherein at least a substantial part of the second cutter assembly is positioned closer to the operating handle than the first cutter assembly.
4. A hand tool according to any one of the preceding claims wherein the support body defines the or each said opening through which, in use, cut material is directed from the second cutter assembly to the collection chamber.

RSTSCL4a
5. A hand tool according to any one of the preceding claims wherein the support body is of a substantially cylindrical shape.
6. A hand tool according to any one of the preceding claims wherein one or each of the first and second cutter assemblies is substantially permanently secured to or is integral with the support body.
7. A hand tool according to any one of claims 1 to 5 wherein the or each individual cutter blade or one or each of the cutter assemblies is selectively removable.
8. A hand tool according to any one of the preceding claims wherein the first cutter assembly comprises the same number of cutter blades as the second cutter assembly.
9. A hand tool according to any one of claims 1 to 7 wherein the first cutter assembly comprises fewer cutter blades than the second cutter assembly.
10. A hand tool according to any one of the preceding claims wherein a cutter blade of the first assembly is integrally formed with a cutter blade of the second cutter assembly and said integrally formed blades are removably secured to the support body.
11. A hand tool according to any one of the preceding claims wherein the collection chamber is substantially open at an end region opposite the region of the support body that supports the cutter assemblies.
12. A hand tool according to claim 11 wherein the operating handle is secure relative to the support body by at least two struts that extend therebetween.
13. A hand tool according to any one of the preceding claims and comprising a soil release plate within the collection chamber and free to move axially relative to the support body either by action of material entering the collection chamber or by operation of a release rod secured to the release plate.
14. A hand tool according to claim 13 wherein the soil release plate is dimensioned to lie substantially aligned with and radially inwards of the or each cutter blade of the first cutter assembly.
15. A hand tool according to claim 13 or claim 14 wherein the end of the soil release rod remote from the soil release plate is provided with an end stop engagable with an end of the operating handle such that the soil release plate is prevented from moving axially outwards beyond the first cutter assembly.
16. A hand tool according to any one of claims 13 to 15 wherein the soil release rod is provided with graduated depth markings.
17. A hand tool according to any one of the preceding claims wherein the operating handle comprises a shaft or rod which extends longitudinally and co-axially with said longitudinal axis of rotation of the support body and a crossbar which enables the handle readily to be rotated.
18. A hand tool according to claim 17 wherein said crossbar is integral with said shaft or rod.
19. A hand tool according to claim 17 wherein the crossbar is pivotally secured relative to said shaft or rod.
20. A hand tool according to claim 17 wherein said crossbar is insertable in and removable from a connection socket secured to said shaft or rod.
21. A hand tool according to any one of the preceding claims wherein the operating handle comprises a shaft or rod which extends in the direction of said longitudinal axis and is provided with depth markings.
22. A hand tool according to any one of the preceding claims wherein the or each cutter blade of the first cutter assembly is inclined relative to a plane perpendicular to said longitudinal axis.
23. A hand tool according to any one of the preceding claims wherein the or each cutter blade of the second cutter assembly is inclined relative to that radial direction which extends between the blade cutting edge and said longitudinal direction.
24.. A hand tool according to claim 1 and substantially as herein before described.RSTSCL3