JP3086397U - Shank rod for portable drill - Google Patents

Abstract

(57) [Summary] In a portable drill to which a hammer drill is applied, by increasing the strength of a shank rod so as to withstand a load or a bending load, a shank rod capable of connecting a drill head for extending a depth is provided. provide. A screw portion (2) for connecting a drill rod is formed at a front end portion, and a polygonal section (3) and a hitting surface (4) to which rotational force and hitting force are transmitted from a drill head are formed at a rear end portion. A concave portion 5 is formed at the middle portion for transmitting the feeding force by being gripped by the drill head, and the rear end surface 5a of the concave portion 5 has an HRC of at least a depth of 2 mm from the surface.
Hardened to a hardness of 40-60.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a shank rod for a portable drill, and more particularly, to a shank rod applied to a simple drill developed for surface soil contamination survey.

[0002]

[Prior art]

 In recent years, contamination of surface soil has become a social problem, and boring has been performed to collect contaminated soil in order to investigate the pollution status. This soil pollution survey boring is often performed in narrow places such as the boundaries of factory sites or indoors, and in such places, machines equipped with drills on large powered vehicles such as crawlers cannot enter. .

[0003] The present applicant has proposed a simple portable drill in which the body of a traveling trolley that can be moved manually is configured as a body frame of the drill (Japanese Utility Model Application No. 2001-005734). This portable drill is equipped with a commercially available drilling power tool as a drill head. This power tool, known as a hammer drill, was originally developed for drilling relatively shallow holes, such as drilling concrete and drilling anchor holes. Therefore, this hammer drill does not have the technical idea of responding to the required drilling depth by connecting drill rods one by one like a boring machine for ground excavation.

Therefore, when boring a soil contamination using a hammer drill as a drill head, a core tube for collecting a soil sample is directly connected to the shank rod, which limits the depth of core collection. Occurs. Drilling can be performed to the required depth by digging while sequentially connecting the drill rod to the shank rod, but the following problems occur.

[0005] (1) Since there is no technical idea of extending the connection of the drill rod to the shank rod for the hammer drill, if the drill rod is connected, the strength against a pulling load or a bending load that increases in proportion to the depth extension is provided. Problems arise. Specifically, at the rear end face of the recess formed in the middle part of the shank rod, which bears the pulling load, the progress of the wear accelerates with the increase of the pulling load, resulting in breakage in a short time.

(2) When collecting a soil sample in the core tube, airtightness occurs between the soil sample and the core tube, so that air in the core tube is not released. For this reason, the air pressure in the core tube rises as the sample enters, and the sample collapses, or the sampling of the sample is interrupted due to the balance between the air pressure and the feeding force, and the predetermined length of the sample is stopped. Sometimes sampling is not possible. Furthermore, if the sample collected in the core tube and the air in the core tube are compressed, if the core tube is pulled up to the ground, the sample may be discharged from the core tube by the compressed air. is there.

[0007] (3) In a general boring equipped with a normal drill head, drilling fluid can be sent to a bit using a shaft hole of a drill rod as a flow path, and drilling chips can be transported and collected on the ground. However, in hammer drills, there is no technical idea of extending the drill rod to the shank rod, so drilling fluid cannot be sent to the bit.

[0008]

[Problems to be solved by the invention]

 This invention has been made based on the above technical background, and achieves the following objectives.

An object of the present invention is to provide a portable drill to which a hammer drill is applied by increasing the strength of the shank rod so as to be able to withstand a load or a bending load so that a shank rod to which a drill rod for extending the depth can be connected is provided. It is to provide.

Another object of the present invention is to provide a shank that can release air in the core tube to the ground when collecting a soil sample in the core tube, thereby preventing the sample from crushing and other problems. It is to provide a rod.

[0011] Yet another object of the invention is to provide a shank rod capable of delivering drilling fluid to a bit.

[0012]

[Means for Solving the Problems]

 This invention employs the following means to achieve the above object. That is, the present invention is directed to a portable drill which is equipped with a drill head made of a power tool for drilling and can be moved by hand, and is provided with a shank rod which is gripped by the drill head and connects the drill head to the drill rod. A thread portion for connecting the drill rod is formed at a front end portion, and a polygonal cross-section portion and a hitting surface are formed at a rear end portion, to which a rotational force and a hitting force are transmitted from the drill head, respectively. A recess is formed at an intermediate portion for transmitting a feeding force while being gripped by the drill head, and a rear end surface of the recess is hardened to an HRC hardness of 40 to 60 at least to a depth of 2 mm from the surface. A shank rod for a portable drill, characterized in that:

The polygonal cross section and the impact surface may also be hardened to an HRC hardness of 40 to 60 at least at a depth of 2 mm from the surface.

[0014] Furthermore, the shank rod is provided with fluid flow paths that are opened on the tip end face and the side face, respectively. The fluid flow path forms an air passage for releasing air when collecting a sample in a core tube attached to the tip of the drill rod. Alternatively, the fluid channel forms a water passage for supplying drilling water to the bit through the drill rod.

[0015]

[Embodiment of the invention]

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a portable drill to which the shank rod of the present invention is applied, and FIG. 2 is a side view. The portable drill 50 can be turned upside down, and the drawing shows an upright state. The frame 51 of the portable drill 50 has a pair of wheels 52 at the tip. A handle 53 for an operator to operate is provided on the back side of the frame 51, and the frame 51 can be run by human power in a state where the frame 51 is folded down. That is, the traveling bogie is constituted by the frame 51, the wheels 52, the handle 53, and the like of the portable drill 50.

The frame 51 is provided with a plurality (two in this embodiment) of guide shafts 54 a and 54 b extending in the same direction. A bracket 55 is provided to be able to move up and down along the guide shafts 54a and 54b. A gauge 56 is written on one of the guide shafts 54b so that the vertical stroke can be visually checked.

A drill head 57 is detachably held on the bracket 55 via a holder 56. Drill head 57 is a commercially available drilling power tool known as a hammer drill. As is well known, the hammer drill 57 has a chuck mechanism 58 for gripping a shank rod, which will be described later, at its tip, and also incorporates a rotation mechanism and a striking mechanism (not shown).

A pinion 59 is rotatably provided on the bracket 55, and the pinion 59 is engaged with a rack 60 provided on the frame 51 in the same direction as the pinion 59. A ratchet handle 61 is provided on the shaft of the pinion 59, and the bracket 55 moves up and down by rotating the ratchet handle 61. As a result, the hammer drill 57 is provided with a feeding force for drilling. The position of the hammer drill 57 shown by a chain line in FIG. 1 is the lowered position.

A bracket 63 for fixing the frame 51 to a base 62 is provided at the end of the frame 51. The base 62 includes a fixed base 62a and a slide base 62b, and the slide base 62b can be freely inserted into and removed from the inside of the fixed base 62a. The bracket 63 is fixed on the fixed base portion 62a by the fastening member 65 with the slide base portion 62b pulled out. The fixed base portion 62a and the slide base portion 62b are fixed to the ground by the anchor 64. The configuration of the portable drill 50 described above is the same as that disclosed by the present applicant in Japanese Utility Model Application No. 2001-005734.

FIG. 3 is a plan view showing a shank rod according to the present invention. The shank rod 1 is gripped by the hammer drill 57, and is made of an alloy steel such as SCM because it transmits a rotational force and a striking force. At the tip of the shank rod 1, a male screw portion 2 for connecting a drill rod described later is formed. In addition, a polygonal cross section 3 and a hitting surface 4 to which a rotational force and a hitting force are transmitted from a hammer drill 57 are formed at a rear end of the shank rod 1. The polygonal section 3 is a portion formed in a hexagonal section in this embodiment, and the striking face 4 is a rear end face of the shank rod 1.

Further, a concave portion 5 having an outer diameter smaller than the circumscribed circle of the polygonal cross section 3 is formed in the intermediate portion of the shank rod 1 over the entire circumferential direction. The recess 5 is a portion that is gripped by the chuck 58 of the hammer drill 57 and transmits the feeding force. For example, a plurality of balls 6 are incorporated in the chuck 58 of the hammer drill 57, and the balls 6 move in the radial direction of the shank rod 1, thereby gripping or releasing the gripping of the shank rod 1. I have.

According to the present invention, the rear end face 5a of the concave portion 5 is hardened to an HRC hardness of 40 to 60 at least at a depth of 2 mm from the surface. Similarly, the polygonal cross section 3 and the striking surface 4 are also hardened in the same depth range and the same hardness range. Well-known heat treatment techniques such as high-frequency quenching, carburizing and quenching, and nitriding can be applied to the surface hardening treatment.

The shank rod 1 is further provided with a spanner hook 7 between the distal male screw portion 2 and the concave portion 5. This spanner hook 7 is for facilitating the work of attaching and detaching screws when connecting or disconnecting the drill rod to the shank rod 1. The shank rod 1 is further formed with a fluid flow path 8 which is open at the tip end surface and side surface (see FIGS. 4 and 5).

FIG. 4 shows a state in which a plurality of drill rods 10 are connected to the shank rod 1, and a core tube 12 is connected to the leading drill rod 10 via a rod sub 11. In this state, the fluid passage 8 of the shank rod 1 communicates with the shaft hole 13 of the drill rod 10. The rod sub 11 has a shaft hole 14 communicating with the shaft hole 13 of the drill rod 10, and a valve 15 that moves up and down is provided in the shaft hole 14. Reference numerals 16a and 16b denote split tubes disposed in the core tube 12, and reference numeral 17 denotes a bit attached to the tip of the core tube 12.

The ground is excavated by gripping the shank rod 1 with the hammer drill 57 of the portable drill 50 shown in FIGS. As the drilling depth is extended, the drill rods 10 are sequentially added. At a predetermined depth, soil for investigating the state of contamination is collected in the core tube 12, and after collection, the core tube 12 is pulled up while cutting off the drill rod 10.

According to the above embodiment, since the shank rod 1 has been subjected to the predetermined hardening treatment, it is possible to connect the drill rod 10 and extend the drilling depth. In other words, even if the lifting load or bending load increases as the depth increases, the depth can be extended because it has the strength to withstand it.

When a soil sample is collected in the core tube 12, the fluid flow path 8 provided in the shank rod 1 functions as a vent. That is, the air in the core tube 12 is opened by moving the valve 15 upward, and is discharged to the ground through the shaft holes 14 and 13 and the fluid flow path 8. Therefore, crushing of the soil sample and other problems can be prevented.

FIG. 5 is a sectional view showing an embodiment in which the function of the fluid flow path 8 is different. In this embodiment, a swivel case 20 is rotatably provided on the outer periphery of the shank rod 1. The annular flow path 21 of the swivel case 20 communicates with the fluid flow path 8, and a pipe (not shown) is connected to the screw portion 22. Therefore, in this case, the fluid flow path 8 functions as a water passage, can supply drilling fluid to the bit 17 at the tip of the core tube, and can discharge cutting waste to the ground.

[0029]

[Effect of the invention]

 As described above, according to the present invention, in a portable drill to which a hammer drill is applied, the structure is such that the shank rod can withstand a lifting load or a bending load, so that a drill rod for extending the depth can be connected. Further, when collecting a soil sample in the core tube, the air in the core tube can be released to the ground, so that crushing of the sample and other problems can be prevented. In addition, by incorporating a swivel into the shank rod, drilling fluid can be sent to the bit as in the case of ordinary boring, and the swarf that is an obstacle to depth extension can be discharged to the ground.

[Brief description of the drawings]

FIG. 1 is a front view showing a portable drill to which a shank rod of the present invention is applied.

FIG. 2 is a side view of the portable drill.

FIG. 3 is a plan view showing a shank rod according to the present invention.

FIG. 4 is a sectional view showing a state where a drill rod is connected to a shank rod.

FIG. 5 is a cross-sectional view showing a state where a swivel is incorporated in a shank rod.

[Explanation of symbols]

 1: Shank rod 2: Male screw part 3: Polygonal cross section 4: Striking surface 5: Recess 5a: Rear end surface 8: Fluid flow path 10: Drill rod 12: Core tube 15: Valve 17: Bit 20: Swivel case 50: Portable drill 51: Frame 52: Wheels 54a, 54b: Guide shaft 55: Bracket 57: Drill head (hammer drill) 58: Chuck

Claims (5)

[Utility model registration claims] 1. A hand-held portable drill equipped with a drill head comprising a drilling power tool, the shank rod being gripped by the drill head and connecting the drill head to the drill rod. A thread portion for connecting the drill rod is formed at a tip end, and a polygonal cross section and a striking surface are formed at a rear end to which rotational force and striking force are transmitted from the drill head, respectively. A concave portion for transmitting a feeding force by being gripped by the drill head is formed in the portion, and a rear end surface of the concave portion is hardened to an HRC hardness of 40 to 60 at least to a depth of 2 mm from the surface. Shank rod for portable drills. 2. The polygonal cross section and the hitting surface are also
HRC hardness 40-6 at least to a depth of 2 mm from the surface
The shank rod for a portable drill according to claim 1, wherein the shank rod is hardened to zero. 3. A shank rod for a portable drill according to claim 1, wherein fluid passages are provided at the tip end face and the side face, respectively. 4. The system according to claim 3, wherein the fluid flow path forms an air passage for allowing air to escape when a sample is collected in a core tube attached to the tip of the drill rod.
The described shank rod for a portable drill. 5. The shank rod for a portable drill according to claim 3, wherein the fluid passage forms a water passage for supplying drilling water to the bit through the drill rod.