SOIL AUGER

Background of the Invention

1. Field of the Invention

The present invention relates to a soil auger adapted for use with a portable, motor driven drill.

2. Description of the Prior Art

It is often desirable to quickly obtain a number of holes of the same diameter and depth in the ground in such tasks as gardening and fencing. A variety of methods for digging such holes are commonly employed, including shovels, post-hole diggers and hand-held bulb planters. Coring devices such as the combination soil auger and soil core sampler disclosed by U.S. Patent No. 4,653,335 also are useful for producing holes in the ground. However, none of these devices are adapted to be used with a portable power source and thus must be manually operated, resulting in the need for increased time and effort by the user.

A power driven screw-type auger is disclosed in U.S. Patent No. 3,356,168. However, this auger does not produce a uniform plug of soil for removal but rather distributes the soil around the edge of the hole it produces.

From DE-C-5419 an auger is known comprising the features of the preamble of claim 1. This device is intended for use in coal mining and is not adapted to produce a uniform plug of material for removal but to distribute the material through the aperture of the sidewall.

US-A-1 456 153 discloses an auger which may be used as a soil auger. The auger has a cylindrical body having an open end for receiving soil into a substantially open cavity and an opposing end which mounts an externally extending shaft. Said body presents, at said open end, a circumferentially oriented margin presenting a plurality of ground engaging teeth. There are no notches provided at said margin, and also, there are no apertures provided in the side walls. This auger is not adapted to be used with a portable power source.

Summary of the Invention

According to the invention a soil auger is provided having a cylindrical tubular body including a sidewall, an open end for receiving soil into a substantially open cavity therewithin with at least one aperture in the side wall and an opposing end which mounts an externally extending shaft adapted to be mounted to a motor driven drill and axially aligned with the center of said body, said body presenting a circumferentially oriented margin at said open end, said aperture does not extend to said margin, said margin along which a plurality of ground engaging teeth are disposed to provide a cut of greater width than the thickness of said side wall, said teeth including a normally lowermost terminus and an upwardly extending gullet therebetween, characterized in that said margin includes a pair of opposed notches dividing said margin in segments carrying said teeth and defining discontinuities in said margin, said notches extending upwardly from said margin but not extending into said aperture, said gullet extends upwardly length less that the upward extension of said notches.

Brief Description of the Drawings

• Figure 1 is an elevational view of the soil auger in accordance with the present invention;
• Fig. 2 is a bottom plan view of the soil auger shown in Fig. 1;
• Fig. 3 is an elevational view of the soil auger shown in Fig. 1 and showing the portion thereof not fully shown in Fig. 1;
• Fig. 4 is a top plan view of the soil auger as shown in Fig. 3;
• Fig. 5 is an enlarged fragmentary bottom plan view of the soil auger shown in Fig. 1 and showing the placement the teeth on the lower margin of the body;
• Fig. 6 is an enlarged fragmentary perspective view of the auger shown in Fig. 1 and showing the alignment of the teeth around the lower margin of the body;
• Fig. 7 is an elevational view of the soil auger shown in use coupled to a conventional electric drill.

Description of the Preferred Embodiment

A soil auger 10, in accordance with the present invention, broadly includes cylindrical tubular body 12 which defines soil holding cavity 14 and terminates in an open end 16 which has a margin 18 from which project a plurality of teeth 20. A top, opposite end 22 of the body 12 is provided with a shaft 24 adapted for attachment to rotary drive means such as a portable electric drill.

In more detail, soil auger 10 is provided with body 12 which is of integral construction and includes at least one, and preferably two apertures 26 in the side wall 28. The body 12 is cylindrical and is provided with cavity 14 for the retention of soil after the desired penetration into the earth has been achieved. Further, the body is preferably constructed of steel to provide sufficient strength in order that the side walls 28 may be relatively thin. By keeping the thickness of the side walls less than 1/8˝, the body may be economically formed with the further advantage that a minimum dislodgement of soil will occur as the auger enters the ground.

Apertures 26 extend through side walls 28 along the major portion of the length between top end 22 and open end 16. The apertures 26 are directly opposed to maintain the auger 10 in dynamic balance as the auger 10 is rotated at high speed. When more than two apertures 26 are provided, they are equally spaced around the side wall 28. In the preferred embodiment, apertures 26 do not extend to lower margin 18, thereby providing a portion of side wall 28 to extend around the lower margin to provide additional rigidity.

Top end 22 mounts shaft 24 to body 12. Top end 22 is preferably enclosed to provide greater torsional rigidity between shaft 24 and body 12. Shaft 24 may be directly coupled to body 12, as by welding, and may be provided with a collar 30 for additional support. Alternatively, shaft 24 may be coupled to body 22 by an arbor or by nuts threaded on the shaft 24 above and below top end 22. Shaft 24 is preferably provided with three equally spaced flat surfaces 32 as shown in Fig. 4. The three flat surfaces 32 permit positive engagement of shaft 24 with the chuck of an electric drill.

At the end opposite top end 22 of body 12 is open end 16. Open end 16 is defined by margin 18 of side wall 28 from which project a series of teeth 20. The teeth 20 are alternately angled inward and outward of the plane of side wall 28, as shown in detail in Fig. 5. Thus, the displacement of the teeth 20 is such that the cut or kerf made in the soil by the auger 10 is slightly wider than the thickness of the body 12. Alternately, the teeth 20 may be provided with additional material so that each tooth 20 is wider than the thickness of the side walls 28, or a lug or protuberance placed on a side of the tooth 20. The teeth are continuously serrated along margin 18 so that there is no location along the lower margin 18 which is not toothed. Each tooth 20 preferably extends no more than one half inch beyond the margin 18 and the space between teeth points 34 is preferably no great than 1/2˝, thus preventing binding of the auger when the auger 10 is coupled to a low-torque motor as is commonly found in household electric drills.

Body 10 may be provided with a pair of opposed notches such as 36 extending into margin 18 as shown in detail in Fig. 6. The notches 36 assist in preventing the clogging of cavity 14 by heavy soils.

In operation, the soil auger 10 is coupled to the chuck 38 of electric drill 40. After the drill 40 is energized, the auger 10 is inserted vertically into the ground 42 to the desired level of penetration. Upon removal of the auger, a quantity of soil is retained in cavity 14. The soil may be removed through apertures 26 as loose soil or as a plug by pushing through apertures 26 in a downward direction on the plug and forcing it out open end 16. Thus, a series of holes may be easily driven.