WO2003006782A1

WO2003006782A1 - Hole digger

Info

Publication number: WO2003006782A1
Application number: PCT/IB2002/002705
Authority: WO
Inventors: David Carl Swartz
Original assignee: David Carl Swartz
Priority date: 2001-07-11
Filing date: 2002-07-10
Publication date: 2003-01-23
Also published as: US20030010537A1

Abstract

The present invention relates to post hole diggers. In particular, the present invention describes a post hole digger that constructs uniform diameter holes. The post hole digger of the present invention is comprised of a pair of handles (8), digging scoops (28) and a hinge bracket (9). The hinge bracket (9) translates the movement of the handles (8) into movement of the scoops (28). The hinge bracket restricts the movement of the handles as digging occurs, allowing for the construction of a relatively straight-sided post hole, essentially removes the tapering of a hole as the hole becomes deeper.

Description

TITLE HOLE DIGGER DESCRIPTION Field of the invention The present invention relates to hole diggers.

In particular, the invention describes a post hole digger that makes uniform diameter holes. Background of the Invention

To utilize the post hole diggers generally in use, the hole digger is thrust into the ground and the handles are pulled apart to close the blades and scoop out the dirt. As the hole becomes deeper, the upper portion of the hole becomes progressively wider and larger in diameter. A three-foot deep hole made with a traditional hole digger with a closed blade having an approximate diameter only five inches must be opened up ten to eleven inches at the top. The hole created will be tapered which creates a lack of ground support when concrete or similar fill material is used to keep a post or pole in position. The instant invention enables the digging of post holes of essentially uniform diameter from ground surface level to the bottom of the hole.

Summary of the invention The present invention is able to dig a hole without appreciably enlarging the upper section of the hole. The present device is comprised of a pair of handles, two metal scoops and a hinge bracket.

In an alternative embodiment, the device may comprise two unitary pieces incorporating the handle and scoop into one unit with the unitary pieces joined by a hinge bracket .

In another embodiment, each scoop is contiguous with a hinge bracket section, forming one piece. The hinge bracket is designed to limit the movement from the elongated handles and to translate the movement to the scoops . In the most preferred embodiment, the handles slightly cross in front of each other while in the open scoop position and open to form two parallel straight lines when the scoops are closed.

In a preferred embodiment, the scoops are joined together to provide strength and limitation of movement. The digging scoops can be joined together by a bolt.

Alternatively, in another preferred embodiment, one of the scoops may have a fixed protrusion fitted into a slot formed in the second scoop to allow a sliding movement of the first scoop providing a more secure hold on dirt, soil or gravel when the scoops are closed.

The hinge bracket is positioned near the midpoint of the pair of handles.

Alternatively, the hinge bracket is positioned between the midpoint of the handles and the top of the digging scoops. The bracket hinge limits the movement of the handles and translates the handle movement to the digging scoops.

Brief description of the drawings

Other aspects, objects, and advantages of the present invention will become evident on reading the following best mode for carrying out the invention, given by way of example and made with reference to the accompanying drawings, in which: - Figure 1A shows a side view of an embodiment of the post hole digger in which a bolt holds the scoops together.

- Figure IB shows a side view of a preferred embodiment of the post hole digger. - Figure 2 shows a top cross section of the hinge bracket .

- Figure 3A shows the scoops in a preferred embodiment slidably attached using a bolt-slot sliding union. - Figure 3B depicts a pair of unattached scoops.

- Figures 4A and 4B show side views of alternative embodiments of the post hole digger where each scoop is contiguous with a hinge bracket section, forming one piece . - Figure 4C shows a front view of the alternative embodiment shown in Fig. 4B, illustrating the location of the handles at the open position of the scoops.

- Figure 5 shows a front view of an embodiment of the groundbreaking edge of the digging scoop. - Figures 6A and 6B show the post hole digger of the instant invention and a prior art post hole digger, respectively, in operation digging a hole.

Description of a preferred embodiment

The preferred embodiment of the present invention will now be described with reference to accompanying drawings. It will nevertheless be understood that no limitations of the scope of the invention is thereby intended, such alterations as scale of the parts, materials used, position of the hinge bracket, color or weight which would fall within the spirit and the scope of the invention described herein.

Figure 1A shows a side view of one embodiment of the post hole digger 14. The post hole digger 14 is comprised of two handles 8 approximately four to six feet long with a diameter of approximately one inch. Blades 12a and 13a of scoop 28 are fixedly attached at one end of one of each handle 8. The handles 8 are joined by a hinge bracket 9 attached to the two handles . The hinge bracket 9 has a pin 7 that rotates to translate the motion applied to the handles 8 into movement of the scoops 28 allowing the opening and closing of the scoops 28. In a preferred embodiment, the hinge bracket is located at a midpoint on the handles with the midpoint defined as the point midway between the top 29 of scoop 28 and the top of the handles. In an alternative preferred embodiment, the hinge bracket 9 may be located between the midpoint and the top of the scoops. In the embodiment shown in Fig. 1A, the scoops are securely joined together by a bolt 29. In the present invention it is not necessary to have the scoop joined but it is a preferred embodiment to provide strength and restrain movement. It should be recognized that the handle/scoop component can be fabricated into a single unitary part, such as by forging, with two such unitary parts joined using hinge bracket 9 and the scoop attachment bolt 29 noted supra. Figure IB shows an alternative preferred embodiment of the post hole digger 14. As in figure 1A the device has a pair of handles 8, two digging scoops 12 and 13 and a hinge bracket 9. The location and function of the hinge bracket 9 is as in fig. 1A. At the end of each handle 8 a scoop blade 12 or 13 is fixedly secured. In the upper portion of scoop 12 is fixed protrusion 11. The upper portion of opposite scoop blade 13 has a slot 10 that slides forward and backward on the fixed protrusion 11. In one embodiment, protrusion 11 may be a bolt. The top or head of the protrusion may be wider then slot 10 to ensure the protrusion will be confined within the slot 10. The efficiency and closing power of the movement of scoop blades 12 and 13 is enhanced by the sliding of scoop 12 into and away from scoop 13.

Fig. 2 shows a cross sectional view of the hinge bracket 9 and the handles 8 of the post hole digger. The handles 8 are securely attached to the hinge bracket by a screw 18 that passes through the hinge bracket 9 and attaches hinge bracket 9 to the handle 8. In the preferred embodiment, shown in figure 7, the screw extends into handle 8 approximately one-half the diameter of handle 8. It is recognized that other attachment methods are possible such as a nut and bolt combination, adhesive or rivets. The hinge bracket 9 has a rotatable attachment 17 joining the two halves of the hinge bracket 9 between the handles 8. The rotatable attachment 17 rotates to translate the motion applied to the handles to the opening and closing of the scoops for the removal of dirt from the hole. This allows for the digging of a hole of essentially uniform diameter in which the width or diameter of the hole is only slightly larger than the distance between scoop blades 12 and 13 in the open position without appreciably enlarging the upper portion of the hole. The hinge bracket 9 is preferably made of hardened steel and the handles 8 of wood. It is recognized that other durable materials can be used to fabricate hinge bracket 9, such as aluminum, plastics, and other suitable materials known in the art. Suitable metals, fiberglass, plastic and plastic coated materials can be used to fabricate handles 8.

Figure 3A shows an enlarged side view of the scoops. In figure 3A, arrow 15 depicts the direction in which scoop blade 13 slides on protrusion 11 which projects through slot 10. Scoop blades 12 and 13 are able to slide into or away from each other. The scoops of the post hole digger can be made of any material that is suitable for outdoor use and digging. Preferably the material will be durable, generally non- corroding and substantially lightweight. Some of the materials that may be used include, but are not limited to aluminum, hardened steel and others. In a preferred embodiment, the scoop blades will be made of hardened steel. The material composing the scoop blades can be varied accordingly to the type of soil being dug such as a loose sandy soil or a hard-packed clay soil. The scoops can be attached to the handle by pressure insertion or by a bolt or a screw or by other methods well known in the art.

Fig. 3B depicts the scoops in an alternative embodiment in which both scoops are identical. One side of the upper portion scoop blade 6a defines a hole 16 through which protrusion 11 passes. (See Figure 3A) . The opposite side of the upper portion of scoop blade 6a defines a slot 10 that will allow for the sliding movement. Once the hole 16 and the slot 10 from each pair of scoop blades 6a are aligned, the protrusion 11 is passed through both holes 16 and is secured. In one embodiment, protrusion 11 is a bolt. In a variation, protrusion 11 may be two bolts used to connect the pair of scoops 6a together. In either variation, the top or head of the protrusion is wider than the width of the slot 10 allowing for stable sliding movement and stronger closing power. The head of the protrusion 11 is defined as part or all of that portion of the protrusion that extends through slot 10. Fig 3B also depicts a receiving section 32 formed to receive handle 8. Persons of ordinary skill in the art will recognize that other methods exist to movably attach scoops 6a to handles 8 such as rods with internal or external threading to receive bolts, nuts or rivets and threaded receiving section 32 adapted to receive a handle with a compatibly threaded end.

Figures 4A and 4B show side views of alternative embodiments of the post hole digger where each scoop is contiguous with a hinge bracket section, together forming one piece. In figure 4A an alternative embodiment of the post hole digger 14 has each scoop 30 and 32 contiguous with a hinge bracket section 37 and 38, respectively, each forming one piece with scoop blade 30 and 32 respectively. It should be recognized that the handle/scoop component can be fabricated into a single unitary part with each unitary part joined to form post hole digger 14. As in figure 1A, the device has a pair of handles 8, two digging scoops 30 and 32 and a hinge bracket formed by sections 37 and 38. In this view the sections 37 and 38 of the hinge bracket keep the scoops section 30 and 32 in an angle. It should be appreciated that hinge sections 37 and 38 may be attached in an approximately straight line perpendicularly transversing the handles 8 at the top of the hinge similar to the embodiment of figure IB. The trimming at the sides of the hinge bracket allows for more power or force to be applied to the scoops. The scoop 30 is elongated in the upper section to join a section from the hinge bracket section 37 to form one contiguous piece. Similarly, hinge section 38 is joined with scoop 32 to form one contiguous piece. In a preferred embodiment, hinge bolt 7 is located 20-21 inches from the scoop tip 40. In a more preferred embodiment hinge bolt 7 is 10-18 inches from the scoop tip 40. In a most preferred embodiment, hinge bolt 7 is 12-14 inches from the scoop tip 40. However, any suitable distance between the hinge bolt 7 and scoop tip 40 will allow the hinge bracket to translate the movement of handles 8 to the scoop blades 30 and 32 enabling the scoops to close. It should be understood that the hole digger is still functional if the bracket is located at the midpoint as in fig.lA or as low as approximately 16 inches above the scoop tip. At the end of each handle 8, a scoop blade 30 or 32 is fixedly secured with a screw 39. It can be appreciated that other means available to someone of ordinary skill in the art could be used to secure the handle to the scoop blade, such as adhesive, bolts, threaded connections or pressure fitting. In the upper portion of scoop 32 is a fixed bolt 11 as in fig. IB. The upper portion of opposite scoop blade 30 has a slot 10 that slides forward and backward on the fixed bolt 11 as in fig. IB. The efficiency and closing power of the movement of scoop blades 30 and 32 is enhanced by the sliding of scoop 30 into and away from the fixed scoop 32. It should be understood that the hole digger also functions if the scoops are joined by a bolt 29 as in fig. 1A or are not joined except by the hinge bracket sections .

Fig. 4B illustrates a most preferred embodiment of the post hole digger 14 where each scoop 42 and 43 is contiguous with a hinge bracket section 40 or 41, forming one piece. The post hole digger 14 shown in figure 4B is similar to the post hole digger 14 shown in fig. 4A except for the cutout region 44 present in 4A and the angled handles 8 shown in fig. 4B. The contiguous region from scoop 42 to hinge section 40 forms a solid panel 45 that defines slot 10. The arrangement of scoop 43 and hinge section 41 are the same as that of scoop 42 and hinge section 40. The solid panel 45 adds strength and leverage to the design. In the most preferred embodiment depicted in fig. 4B, solid panel 45 measures approximately 4 inches from hinge bolt 7 to sliding bolt 11. However, persons skilled in the art will understand that the use of shorter and longer solid panels will allow the attached hinge bracket sections 40 and 41 to translate the movement of the handles scoops 42 and 43 enabling the scoops to close. It also should be understood that the hole digger is still functional if the bracket is located as in fig.lA or as in fig. 4A. In this most preferred embodiment, the handles 8 cross in front of each other when the scoops of the digger are in the open position. Figure 4C illustrates a front view of this most preferred alternate embodiment. It can be appreciated in fig. 4C that the handles, when in the crossed position, allow for a space to be present at the top of the handles. The operator of the hole digger moves the handles away from each other to close the scoops and remove the dirt from the hole.

Figure 5 shows an enlarged front view of an alternative embodiment of scoop blade 35. The figure depicts the ground braking edge or blade of the scoop with teeth 33. The teeth 33 at the tip have a slight bend towards the opposite scoop. The bend of the teeth has an angle 34 in the range of 00 to 280 degrees. In the most preferred embodiment, the bend angle 34 is between 180 to 220 degrees. The teeth 33 with the slight angle 34 at the edge contribute to closing of the scoops with less force, making removal of dirt from the hole less tiring when digging in certain soils. The teeth 33 can be present or absent from the digging blades in any of the embodiments presented in this application.

Figs. 6A and 6B depict the one embodiment of post hole digger of the instant invention and a prior art post hole digger, respectively, in operation. In Fig. 6A, it can be appreciated that the hole 19 dug by the post hole digger 14 of the present invention is relatively uniform in diameter from top to bottom. In comparison, the hole dug by the prior art post hole digger 27 is wider at the ground surface than at the bottom. The prior art post hole digger 27 has two scoop blades 26 and 24 and a bolt 25 joining both scoop blades. Both of the scoops are fixed in position by the bolt 25 whereas in the present invention post hole digger 14 has a fixed scoop 43 and a sliding moving scoop 42. It can be appreciated that each of the scoops is contiguous with a hinge bracket section 40 or 41, forming one piece. The hinge bracket limits the movement of the handles 8. The hinge bracket has a pin 7 that rotates to translate the minimum motion applied to the handles 8 into movement of the scoops 42 and 43 allowing the opening and closing of the scoops 42 and 43. In this figure the scoops 42 and 43 are closed, showing the uncrossing of the handles 8. Line 21 illustrates the width of the open handles. In contrast, with the prior art post hole digger 27, as the hole 20 becomes deeper, the movement of the handles 23 becomes wider and more extreme creating a tapered hole rather the more uniform hole 19 fashioned by post hole digger 14 of the instant invention. The teeth 33 can also be observed in the close position of the scoops, allowing for a better grasp of dirt with a minimum of force in some soils. Persons skilled in the art will realize that in all embodiments described herein, longer handles and suitably placed hinge brackets or hinge sections will enable the digging of deeper holes with approximately uniform diameter.

Claims

1. A hole digger for making uniform diameter holes, comprising :

- a pair of elongated handles each one of said pair having a first end and a second end;

- a pair of digging scoops, the first one of said pair of digging scoops attached to said first end of the first one of said pair of elongated handles and the second one of said pair of digging scoops attached to said first end of the second one of said pair of elongated handles; and,

- a hinge bracket securely attached on and between each of said first and said second end of said handles.

2. A hole digger for making uniform diameter holes, comprising:

- a pair of elongated handles each with a first end and a second end;

- a pair of digging scoops, the first one of said pair of digging scoops fixedly attached to one of said first end of said handles, and the second one of said pair of digging scoops attached to said first end of the second one of said pair of elongated handles, each one of said pair of digging scoops movably joined to each other; and - a hinge bracket securely attached on and between each of said handles .

3. A hole digger for making uniform diameter holes comprising:

- a pair of elongated unitary parts, each one of said pair of elongated unitary parts having two ends wherein the first one of said ends is shaped as a digging scoop, each scoop having a top end, an upper portion and a groundbreaking edge, and the remaining portion of each of said elongated unitary parts forming an elongated handle; and

- a hinge bracket securely attached on and between each of said elongated handles. 4. A hole digger for making uniform diameter holes comprising :

- a pair of elongated handles each with a first end and a second end;

- a pair of digging scoops, the first one of said pair of digging scoops contiguous with a first hinge bracket section and attached to said first end of said first one of said pair of said elongated handles,

- the second one of said pair of digging scoops contiguous with a second hinge bracket section and attached to said first end of said second one of said pair of elongated handles, each one of said pair of scoops including a groundbreaking edge, and an upper portion, the upper portion of said first one of said pair of digging scoops and the upper portion of said second one of said pair of scoops being movably secured to each other;

- and said first hinge bracket section and said second hinge bracket sections being operatively joined together. 5. A hole digger according to according any of the previous claims, wherein said elongated handles cross when said digging scoops are in the open position.

6. A hole digger according to claim any of the previous claims, wherein said scoops comprise a groundbreaking edge, said ground breaking edge having teeth.

7. A hole digger according to claim 6 wherein the teeth of said first one of said scoops incline toward said second one of said scoops and the teeth of said second one of said scoops incline toward said first one of said pair of scoops.

8. A hole digger according to claim 10 wherein said teeth incline at an angle in the range of 0° to 28° degrees.

9. A hole digger according to any of the previous claims, wherein said or each hinge bracket is located at a midpoint between said second end of each of said elongated handles and a top of said or each scoop. lo. A hole digger according to any of the claims from 1 to 8, wherein said or each hinge bracket is located between said top of said or each scoop and said midpoint of said elongated handles. li. A hole digger according any of the previous claims, wherein said handles are removably secured to said hinge brackets by a screw.

12. A hole digger according to any of the previous claims wherein said scoops are pivotally joined by a first bolt. 13. A hole digger according to any of the previous claims, wherein the first one of said pair of digging scoops further comprises an upper portion, said upper portion having at least — one protrusion; and - the second one of said pair of digging scoops further comprises an upper portion, said upper portion defining at least one slot, said at least one slot receiving said at least one protrusion.

14. A hole digger according to any of the claims from 1 to 13, wherein each one of said pair of digging scoops further comprises an upper portion, each one of said upper portions having a first side defining a slot and a second side defining a hole. is. A hole digger according to claim 14 further comprising a protrusion, said protrusion received by said slot and said hole in each one of said pair of digging scoops.

16. A hole digger according to claim 16 wherein said at least one protrusion has a head wider than said at least one slot of said second scoop.

17. A hole digger according to claim 17 wherein said hinge bracket is located four inches above said protrusion.

18. A hole digger of claim 15 wherein said protrusion is a bolt.

19. The hole digger of any of the previous claims, wherein said digging scoops are securely joined to each other.

20. A hole digger according any of the previous claims, wherein said elongated handles are made of wood, said or each digging scoop is made of hardened steel, and said or each hinge bracket is made of hardened steel .

2i. The hole digger according to according any of the previous claims, wherein said elongated handles are 4 to 6 feet long.