US2710765A

US2710765A - Post hole digger

Info

Publication number: US2710765A
Application number: US148655A
Authority: US
Inventors: Arens Charles Anthony
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-03-09
Filing date: 1950-03-09
Publication date: 1955-06-14
Anticipated expiration: 1972-06-14

Description

June 14, 1955 c. A. ARI-:Ns

POST HOLE DIGGER 2 Sheets-Sheet l Filed March 9, 1950 June 14, 1955 c. A. ARENS Pos'r HOLE BIGGER` 2 Sheets-Sheet 2 Filed March 9, 1950 INVENTOR.

POST HLE DHGGER Charles Anthony Arens, Winamac, lnd.

Application March 9, 1950, Serial No. 148,655

8 Claims. (Cl. 294-50.@

This invention is concerned with an improved post hole digger.

In the digging of relatively narrow deep holes such as for the insertion of posts it has been common practice to use post hole diggers which have generally fallen into one of two major classifications. These are the auger type and the clam shell type of post hole diggers.

The auger type of post hole digger is provided with a screw usually of sheet metal and is advanced into the ground with a twisting motion until a receptacle associated with the screw is filled with earth at which time the post hole digger is lifted from the ground and emptied. The auger type post hole digger is generally satisfactory in soft earth but does not satisfactorily bite into hard earth and is stalled completely by rocks which are frequently encountered in the ground. Additionally, it is rather diflicult to dump the earth from the receptacle when it is raised to the surface.

The clam shell type of digger comprises a pair of sharpened shovel blades mounted in close spaced relation on elongated handles pivotally connected adjacent the blades. Digging is accomplished by a series of successive jabs into the ground following which the handles are spread apart to force the shovel blades together to grip the earth so that it may be lifted from the hole and readily dumped to one side. This type of post hole digger operates satisfactorily in any type of earth and can be aimed to dig around and lift rocks rather than being stalled thereby.

Certain disadvantages are attendant upon the clam shell type of post hole digger. The usual vertical handles rub the hands of the operator with a sudden jerking motion each time the digger is jabbed into the earth and causes blisters and callouses. Dirt is often dropped from the blades by failure to keep the handles spread sufiiciently far apart as they are raised. The most important objection to this type of post hole digger is that the depth of a hole that can be dug relative to its width is limited. It is apparent that the distance between the handles as they are spread apart to force the blades together increases from the bottoms to the tops of the handles. As a hole is dug deeper the handles cannot be spread apart sufficiently far to grip the earth unless the top of the hole is enlarged. Enlarging the top of a hole requires removal of additional earth and provides a less firm foundation for a post or rother object set therein.

An object of this invention is the provision of a post hole digger which is more conveniently manipulated than are those known in the prior art.

A further object of the present invention is the provision of a post hole digger of the clam shell type which is capable of digging holes which are deeper relative to their diameter than has heretofore been possible.

Yet another object of this invention is the provision of a post hole digger of the clam shell type in which the blades are self locking in dirt retaining position.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings in which:

Figure 1 is a side elevation partially in section of a post hole digger embodying the elements ofmy invention;

Fig. 2 is a fragmentary side elevation showing certain other parts in a different position;

Fig. 3 is a top view of the handle;

Fig. 4 is a sectional view along the line 4 4 of Fig. 3;

Fig. 5 is a perspective view of the top of the handle;

Fig. 6 is a fragmentary perspective view of a portion of the handle;

Fig; 7 is a fragmentary longitudinal view showing the blades and operating apparatus thereof as taken along the line 7 7 of Fig. 9;

Fig. 8 is a sectional view taken along the line 8 8 of Fig. 7;

Fig. 9 is a cross sectional view taken along the line 9 9 of Fig. l;

Fig. l0 is a perspective view of a part of the shovel operating mechanism;

Fig. 1l is a perspective view of the top part of the shovel blade cooperable therewith; and

Fig. l2 is a view similar to Fig. 9 of a modified structure.

Generally, my improved post hole digger comprises a pair of opposed shovel blades pivotally mounted adjacent the lower end `of a single shaft. In the preferred form the blades are maintained in substantial parallelism by spring members which allow the blades to deiiect upon striking rocks or other impenetrable objects. The shaft comprises a pair of lconcentrically mounted elongated members which are rotatable relative to one another and transverse handles are Secured to the concentrically mounted members adjacent the top ends thereof and a cam is secured to the bottom end of one such member. The transverse handles provide a more convenient hand grip for jabbing the blades into the earth than the vertical handles used heretofore and when moved toward one another rotate the concentrically mounted members relative to one another to cam the shovel blades toward one another into earth retaining position. Apawl and ratchet mechanism is provided to locate the blades in earth retaining position and this mechanism is readily unlocked by hand when it is desired to dump the earth retained between the blades. It may be seen that the single handle is more readily yelevated, from a hole than the pair of handles heretofore used and that the hole dug need not be of appreciably greater diameter than the spring between the shovel blades.

Referring to Fig. 1 first, a post hole digger embodying my invention comprises a shaft 12 having a pair of

opposed shovel blades

14 and 16 pivotally mounted adjacent the lower end thereof. The shaft comprises inner and outer concentric members or

pipes

18 and 20 respectively. A transverse handle 22 is welded or otherwise secured to a collar 24 which is secured by means such as a nut and bolt 26 to the upper end of the inner pipe 18. A second transverse handle 28 is secured to the outer pipe 20 below the collar 26. The handle 28 comprises a tubular member 30 (Fig. 4) welded or otherwise suitably secured to the outer pipe 20. The underside of the collar 24 is provided with a ratchet 32 (see also Fig. 5) and a pawl 34 secured to a grip member 36 concentrically mounted on the tubular member 30 is cooperative with this ratchet. A torsion and tension spring 38 is carried within the handle 28 and is anchored at one end to a cross pin 40 mounted in the tubular member 30. A second cross pin 42 is secured in the grip member 36 adjacent the outer end thereof and provides an anchor for the other end of the spring 38. The tension and torsion spring 38 normally maintains vthe grip member 36 on the tubular member 30 with the cross pin 42 abutting the outer end of the tubular member 30 with the pawl 34 in engagement with the ratchet 32. A pair of notches 44 are provided in the outer end of the tubular member so that the grip member may be twisted a quarter revolution to allow the cross pin 42 to seat in the notches 44 and maintain the pawl 34 out of engagement with the ratchet 32 if it is for any reason desired to disable the automatic locking of the shovel blades.

Referring to Figs. l, 2, 7 and 8, a base plate 46 may be seen to be welded or otherwise secured to the inner pipe 18 of the shaft 12. Blade mounting members 48 each comprising a pair of arms 50, an upstanding flange 52, and top and

rear walls

54 and 56 respectively, are pivotally mounted on depending flanges 53 of theibase plate 46 by transverse bolts or pins 60 spaced through apertures in the depending flanges 58 and the arms 50. Each of the

blades

14 and 16 has sharpened curved lower edges 64 and is provided at its upper edges with anged rear walls 64 (Fig. 11) and side walls or anges 66 substantially perpendicular thereto. The

blades

14 and 16 are identical and may be conventional post hole digger or shovel blades with the top edges cut to form notches 68 to accommodate the blade mounting members 48 and with the outer edges bent in to form the flanges 66. The top of each

blade

14, 16 interlits with a blade mounting member 48 with the rear wall 64 against the outer surface of the wall 56 of the mounting member 48 and with the flanges 66 of each blade in contact with the inner surfaces of the arms of its mounting member. The blades may be secured to the mounting members by welding, by a plurality of rivets or nuts and bolts 70 placed through suitable apertures, or by any other desirable means.

The upper corners of the upstanding ange 52 of each mounting member 48 are apertured as at 72 and coil springs 74 are anchored in these apertures and stretch between opposite anges normally to maintain the blades in spaced substantially parallel position as shown in all of the figures except Fig. 2. A cylindrical cam surface or member 76 is also provided on each upstanding flange 52 and may comprise a length of rod welded in position.

Referring most particularly to Figs. 7-9, and generally to Figs. 1 and 2, a cam 80 may be seen secured by suitable means such as welding, to the outer pipe 20 adjacent the bottom thereof. This cam bears against the camming surfaces or members 76 and is shaped so that when it is rotated counterclockwise as seen in Fig. 9

to bear against these surfaces or members, it will cam readily may be grasped to jab the

blades

14 and 16 into the earth 82 as shown in Fig. l. The handle 28 is turned toward the handle 22 as shown in dotted lines in Fig. 3 to force the shovel blades together and this is most easily done when the handles are not exactly in line at the start. Due to the pawl and ratchet 34 and 32, the han- El,

dles are locked against relative turning away from each other. The turning of the handle 28 turns the outer pipe 20 of the shaft 12 and with it the cam 80 to force the blades together to secure a quantity of earth 34 as shown in Fig. 2. from the earth to dump the quantity of earth retained. Due to the automatic locking of the blad-es in earth retaining position, little or no care need by exercised to avoid spilling the dirt retained. This is a particularly valuble feature when working in a deep hole where the post hole digger is most readily removed by a hand over-hand motion on the shaft 12. To dump the earth retained it is only necessary to rotate the grip member 36 against the action of the spring 38 to free the pawl from the ratchet 32 and turn the handle 28 away from the handle 22 to the full line position of Fig. 3. The

The post hole digger is then lifted springs 74 return the blades to their initial substantially parallel spaced apart position to allow the earth to be dumped.

A modified structure is shown in Fig. 12 wherein most of the parts including the

blades

14 and 16, the blade mounting members 4S, the base plate 46 and shaft 12 may be similar to those described previously. Rather than the cam the outer pipe 20 is provided with a pair or" diametricnlly spaced ears or arms 85. Links 3S are pivotally connected to these ears and to lugs which replace the cylindrical cam members or surfaces 76 on the upstanding anges 52 of the blade mounting members 4S. The tension springs 74 are unnecessary as the

blades

14 and 16 are maintained in spaced apart relation by the arms 83. When the handle 28 is turned toward the handle 2, the arms push the flanges 52 apart and consequently the

blades

14 and 16 move into contiguous relation to retain a quantity of earth. Dumping of the earth is brought about in the same manner as in the earlier modification but in this instance the blades are separated positively through the action of the arms 88 rather than by spring action.

lt is apparent that l have herein presented an improved post hole digger. The post hole digger is of the clam shell type adapted to dig in any soil of any consistency. The upstanding handle or shaft of the post hole digger is provided with transverse handles which are more comfortable iu use than the usual vertical handles and the blades are rorced toward one another by turning the transverse handles toward one another and are automatice. ly locked in order to remove dirt without spilling from a hole of practically any depth relative to its diameter.

Although certain specic embodiments of my invention have been shown, it is to be understood that this is for illustrative purposes only and that my invention is to be limited only by the spirit and scope of the appended claims.

1 claim:

l. A post hole digger comprising an elongated shaft including a pair of relatively rotatable concentric members, a handle carried by each of said concentric members at corresponding ends thereof, a plurality of spaced apart opposed shovel blades pivotally supported by the other end or' one of said concentric members, an arm for i. cach of said shovel blades carried by the other concentric member adjacent said shovel blades, and a link interconnecting each arm and shovel blade to pivot said shovel blades into contiguous relation in response to relative rotation of said concentric members.

2. A post hole digger comprising an elongated shaft including a pair of relatively rotatable concentric members, a pair of elongated handles carried by said concenric members at corresponding ends thereof and at right angles thereto to rotate said members relatively, a ringlile ratchet carried by one of said concentric members adjacent the handle thereon and having ratchet teeth in its face, a pawl carried by handle on the other concentric member for cooperation with said ratchet and releasable by rotation of the handle about its own axis, a plurality of spaced apart opposed shovel blades pivotally supported by one of said concentric members at the end thereof opposite the handle, and means interconnecting said shovel blades and the other concentric mem- 'oer to pivot said shovel blades into contiguous relation in response to movement of said handle means, said pawl and ratchet being spring urged into engagement and automatically locking said shovel blades in contiguous relation.

3. A post hole digger as set forth in claim 2 including means for disabling said pawl and ratchet.

4. A post hole digger comprising a pair of relatively rotatable concentric shafts, a plurality of spaced apart opposed shovel blades pivotally mounted adjacent their upper edges for pivoting movement about axes lying in a plane substantially perpendicular to said shafts adjacent the lower end of said shafts, a pair of handles, one

handle connected to the upper end of the inner shaft and the other handle connected to the upper end of the outer shaft, said handles being adapted to be grasped byA the hands to force said blades into the earth, said handles being mounted for relative movement toward one another, said blades being pivotally connected to the lower end of one shaft, and actuating means connected to the lower end of the other shaft to force the upper ends of said blades apart on relative rotation of said shafts causing the lower edges of said blades to come in closer contiguous relation.

5. A post hole digger comprising a pair of relatively rotatable concentric shafts, a plurality of spaced apart opposed shovel blades pivotally mounted adjacent their upper edges for pivoting movement about axes lying in a plane substantially perpendicular to said shafts adjacent the lower end of said shafts, means normally maintaining said shovel blades in substantial parallelism, a pair of handles, one handle connected to the upper end of the inner shaft and the other handle connected to the upper end of the outer shaft, said handles being adapted to be grasped by the hands to force said blades into the earth, said handles being mounted for relative movement toward one another, said blades being pivotally connected to the lower end of one shaft, and actuating means connected to the lower end of the other shaft to force the upper ends of said blades apart on relative rotation of said shafts causing the lower edges of said blades to come in closer contiguous relation.

6. A post hole digger as set forth in claim 5 including spring and stop means for maintaining said shovel blades in substantial parallelism.

7. A post hole digger comprising a pair of relatively rotatable concentric shafts, a pair of spaced apart opposed shovel blades pivotally mounted adjacent their upper edges for pivoting movement about parallel axes lying in a plane substantially perpendicular to said shafts adjacent the lower end of said shafts, a pair of handles,

one handle connected to the upper end of the inner shaft and the other handle connected to the upper end of the outer shaft, said handles being adapted to be grasped by the hands to force said blades into the earth, said handles being mounted for relative movement toward one another, said blades being pivotally connected to the lower end of one shaft, and actuating means connected to the lower end of the other shaft to force the upper ends of said blades apart on relative rotation of said shafts causing the lower edges of said blades to come in closer contiguous relation.

8. A post hole Vdigger comprising a pair of relatively rotatable concentric shafts, a plurality of spaced apart opposed shovel blades pivotally mounted adjacent their upper edges for pivoting movement about axes lying in a plane substantially perpendicular to said shafts adjacent the lower end of said shafts, a pair of handles, one handle connected to the upper end of the inner shaft and the other handle connected to the upper end of the outer shaft, said handles being adapted to be grasped by the hands to force said blades into the earth, said handles being mounted for relative movement toward one another, said blades being pivotally connected to the lower end of one shaft, and a cam connected to the lower end of the other shaft to force the upper ends of said blades apart on relative rotation of said shafts causing the lower edges of said blades to come in closer contiguous relation.

References Cited in the le of this patent UNITED STATES PATENTS 1,053,730 Jensen Feb. 18, 1913 1,443,138 Littley Jan. 23, 1923 1,553,270 Saold Sept. 8, 1925 2,028,680 Mayeda et al. Ian. 21, 1936 2,219,374 Spurney Oct. 29, 1940 2,435,473 Sonnenberg Feb. 3, 1948