CN211397459U

CN211397459U - Expanding drill bit

Info

Publication number: CN211397459U
Application number: CN201922494836.2U
Authority: CN
Inventors: 李仁民; 刘飞; 王建兰; 杨东升
Original assignee: Jiangsu South & East Geotechnical Technology Co ltd
Current assignee: Jiangsu South & East Geotechnical Technology Co ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-09-01
Anticipated expiration: 2029-12-31

Abstract

The utility model discloses a reaming bit, which comprises a rod piece and a cutting head, wherein the two ends of the rod piece are respectively formed into a reaming end and a cutting end, and the cutting head is arranged at the cutting end of the rod piece; the outer peripheral surface of the reaming end of the rod piece is provided with a reaming blade, the reaming blade is connected to the rod piece through a blade hinge piece, and the reaming blade is provided with a free end; the reaming blade is rotatable between a locked position and a reaming position via a blade hinge; when the reaming blade is positioned at the reaming position, the rotating radius of the reaming blade is larger than the rotating radius of the first helical blade and the cutting head; when the hole expanding drill bit rotates forwards, the hole expanding drill bit can drill downwards, and the hole expanding blades are located at the locking position; when the reaming bit rotates reversely, the reaming blades rotate to the reaming position from the locking position under the action of centrifugal force; when the reamer blade is in the locked position, the reamer blade abuts against the outer peripheral surface of the rod member. The straight cylinder part of the pile hole and the construction of pile bottom reaming can be completed at one time by using the reaming bit.

Description

Expanding drill bit

Technical Field

The utility model particularly relates to a drill bit with reaming function, this drill bit can accomplish the installation of anchor rope under the condition of drilling not withdrawing the drilling rod.

Background

At present, when pile hole bottom expanding is carried out, high-pressure guniting is generally adopted or a special bottom expanding drill bit is replaced to expand the bottom after a straight cylinder part of a pile hole is completed, so that inconvenience is brought to construction, and the construction efficiency is influenced.

At present, the anchor cable is generally installed by firstly forming a drill hole, removing a drill rod from the drill hole, then lowering the anchor cable into the drill hole, and preferably pouring concrete or cement soil to form a pile body. However, as the soil quality of a partial area is loose, in the process of withdrawing the drill rod from the drill hole, the situation of hole wall collapse often occurs, so that the partial drill hole is blocked, the anchor cable cannot reach the set position, and the overall strength of the pile body is affected. In addition, in the process of pouring concrete or cement soil, partial soil enters the concrete or cement soil, and the quality of the pile body is affected.

SUMMERY OF THE UTILITY MODEL

For at least part solution above-mentioned problem, the utility model provides a reaming bit utilizes this reaming bit can once only accomplish the straight section of thick bamboo part in stake hole and the reaming construction at the bottom of the stake. The specific technical scheme is as follows:

a hole expanding drill bit comprises a rod piece and a cutting head, wherein the rod piece extends along an axis and is provided with a cylindrical outer peripheral surface, one end of the rod piece is formed into a hole expanding end, the other end of the rod piece is formed into a cutting end, the cutting head is arranged at the cutting end of the rod piece, and the cutting head is used for cutting a soil body; at least two reaming blades are arranged on the peripheral surface of the reaming end of the rod piece, one end of each reaming blade is connected to the peripheral surface of the rod piece through a blade hinge piece, and the other end of each reaming blade is a free end; the reaming blade is rotatable between a locked position and a reaming position via the blade hinge; a first helical blade is arranged on the peripheral surface of the cutting end of the rod piece; when the reaming blade is positioned at the reaming position, the rotating radius of the reaming blade is larger than the rotating radius of the first helical blade and the cutting head;

when the hole expanding drill bit rotates forwards, the hole expanding drill bit can drill downwards, and the hole expanding blades are located at the locking position; when the reaming bit rotates reversely, the reaming blades rotate to the reaming position from the locking position under the action of centrifugal force;

the reaming blade is arc-shaped and abuts against the outer peripheral surface of the rod when the reaming blade is located at the locking position.

When the hole expanding drill bit is used, the hole expanding blades are located at the locking position during forward rotation, the cutting head can cut and excavate soil, a straight cylinder part of a pile hole is formed, and when hole expanding is ineffective, excavation of the pile hole is completed. When the hole is expanded, the drill bit is rotated reversely, the soil body of the hole expanding blade is pushed to rotate outwards and reaches the hole expanding position, the pile hole is expanded, the drill bit can be moved upwards or downwards to increase the height of the hole expanding part in the vertical direction when the hole is expanded, and after hole expanding construction is completed, the drill bit is rotated forwards again to return to the locking position, and hole expanding construction is completed. By utilizing the reaming bit, the bottom reaming construction of the pile hole can be completed, and the reaming of a plurality of positions on the side wall of the pile hole can be performed along the height direction so as to form the special-shaped pile.

By using the reaming bit, the construction of the straight cylinder part and the pile bottom reaming part of the same pile hole can be completed at one time without replacing the reaming bit, and the construction efficiency can be effectively improved. The step that the drill rod needs to be hoisted out of the pile hole firstly when the drill bit is replaced in the traditional construction is avoided, so that the defect that the construction time is prolonged due to the fact that the hole wall landslide collapses when the drill rod is hoisted out of the pile hole is overcome.

When the hole expanding drill bit rotates forwards, the hole expanding drill bit can drill downwards, the fact that the hole expanding drill bit can only drill downwards when rotating forwards is not meant, the drill bit can be kept at a certain height according to needs, and the hole expanding drill bit can keep rotating forwards or can still keep rotating forwards when being lifted upwards.

Further, an annular projection is formed on the outer peripheral surface of the rod member, a groove is formed on the annular projection in a radially recessed manner, the reamer blade is fitted in the groove, and when the reamer blade is located at the lock position, the outer side surface of the reamer blade does not exceed the outer surface of the annular projection outward.

Set up annular protrusion, and set up the recess back on this annular protrusion, this recess forms the interim protection chamber of reaming blade, when this reaming bit needs to preserve or transport, can lock reaming blade in the recess, avoid reaming blade to receive external impact and damage, simultaneously, at drilling process, reaming bit is just passing, when excavating the earthwork downwards promptly, reaming blade is locked in the recess, reaming blade is located the latched position promptly, reaming blade is inoperative, can not cut soil, because the protection of recess, the wearing and tearing of the soil body to reaming blade have also been avoided simultaneously, can prolong reaming blade's life effectively.

Further, when the reamer blade is in the locked position, a wedge-shaped groove with a small inside and a large outside is formed between the end surface of the free end of the reamer blade and the inner side surface of the groove.

After the wedge-shaped groove is formed, when the reaming blades need to be opened for reaming during drilling, the reaming bit is reversed, soil can enter the wedge-shaped groove at the moment, the reaming blade is pushed, the reaming blade is enabled to rotate outwards around the blade hinged parts and is opened, and when the reaming bit continues to be reversed, reaming can be performed. Namely, after the wedge-shaped groove is arranged, the reaming blades can be smoothly opened by utilizing the soil body so as to carry out reaming construction.

Further, when the reamer blade is in the locked position, the end surface of the free end of the reamer blade is inclined in a radially outward extending direction, away from the inner side surface of the groove opposite thereto, or the end surface of the free end of the reamer blade extends in a radially outward direction. The design ensures that when the reaming bit rotates reversely, the soil body can form outward driving force on the reaming blades so as to smoothly open the reaming blades.

Further, the inner side of the groove facing the reamer blade is inclined in a radially outward extending direction, facing away from the reamer blade, or the inner side of the groove facing the reamer blade extends in a radially outward direction when the reamer blade is in the locked position. This design can avoid forming one between the medial surface of recess and the bottom surface of recess and hold the chamber, when forming this and hold the chamber, can pile up the earthwork at this intracavity that holds, and difficult clearance not only is unfavorable for the cleaning and purification of equipment, has also increased the preparation degree of difficulty of equipment.

Further, the rod member has an inner cavity extending along the axis and penetrating end faces of both ends of the rod member, the cutting head is connected to the cutting end of the rod member via a cutting head hinge member, and the cutting head is rotatable between an open position and a closed position via the cutting head hinge member; under the action of external force, the cutting head can rotate from a closed position to an open position;

the cutting head is provided with a body, the body is provided with a body inner side surface and a body outer side surface opposite to the body inner side surface, and when the cutting head is positioned at a closed position, the body inner side surface of the body is abutted against the end surface of the cutting end of the rod piece; when the cutting head is at the open position, the cutting head does not seal the inner cavity of the rod piece when being observed along the axial direction of the rod piece, and a passage is arranged between the inner cavity of the rod piece and the cutting head;

a cutting knife for cutting soil is formed on the outer side surface of the body, and the blade of the cutting knife protrudes out of the outer side surface of the body.

When the drill bit is arranged at one end of a screw rod, the drill bit can be formed into a drill rod, the screw rod comprises a rod body and rod body spiral sheets which are encircled on the outer peripheral surface of the rod body, the rod body is provided with a through hole which penetrates through the end surfaces of the two ends of the rod body, and the through hole is communicated with the inner cavity of the rod body.

Preferably, to facilitate mounting of the cutting head, a first fixing lug is provided on the cutting end of the rod, and a second fixing lug is provided on the body of the cutting head, which can be detachably coupled to the first fixing lug.

When in use, the hole expanding drill bit can be arranged at the bottom of the hollow rod, and the inner cavity of the hollow rod is communicated with the inner cavity of the rod piece of the hole expanding drill bit, so that a drill rod with a hollow inner cavity which is communicated up and down is formed. After the drilling rod is used for completing excavation of a drilled hole, the drilling rod is temporarily not lifted upwards, then the anchor cable is inserted into the through hole of the hollow rod, the lower end of the anchor cable can abut against the cutting head of the expanding bit, then the drilling rod is lifted upwards and slowly, the cutting head can turn outwards around the hinge piece of the cutting head under the self weight and the abutting pressure of the anchor cable, so that the cutting end of the rod piece is opened, the anchor cable penetrates out of the inner cavities of the hollow rod and the rod piece downwards, the inner cavity reaches a set position, then the drilling rod is lifted upwards out of the ground, and the drilling rod is. Utilize the reamer bit in this application, can sink the anchor rope to the set position after, promote the in-process on ground with the drilling rod, even the condition that the pore wall of taking place drilling collapsed, also no longer cause the influence to sinking of anchor rope.

Further, at least two cutting knives are formed on the outer side surface of the body, and the at least two cutting knives are radially arranged on the outer side surface of the body by taking the central part of the body as the center;

when the cutting head is in the closed position, the cutting blades are elongated and extend in the radial direction of the rod, and the distance from the cutting edge of at least one cutting blade to a first plane perpendicular to the axis and cutting the rod is gradually reduced from the central portion of the body toward the edge of the body.

The design can enable the cutting knife on the cutting head to form a conical body with the middle protruding outwards, the cutting head can be favorably cut into the soil body downwards, meanwhile, when the soil body is cut, the soil body cut off can be pushed to move towards the direction deviating from the cutting head to the periphery, namely, when the cutting head digs downwards along the vertical direction, the soil body cut off is favorably moved upwards, and the soil body is sent to the ground.

Furthermore, at least two tooth grooves are arranged on at least one cutting blade, each tooth groove penetrates through the cutting edge of the cutting blade along the thickness direction of the cutting blade, and the at least two tooth grooves on any cutting blade are arranged at intervals along the extension direction of the cutting blade. After setting up the tooth's socket, when cutting the soil body, can avoid forming massive earthwork, when adopting the hob to carry the earthwork outwards, massive earthwork is at the in-process of upwards output drilling, very easily causes the jam to the helicla flute of hob, makes the earthwork at the in-process of carrying on, owing to receive the extrusion of helicla flute, very easily makes the earthwork form mud thick liquid, is unfavorable for the output of earthwork.

The tooth socket can form small earthwork when cutting the soil body, and reduces extrusion force received in the upward conveying process so as to avoid the earthwork to form slurry to a large extent.

Furthermore, a boss is formed on the inner side surface of the body, and when the cutting head is positioned at the closed position, the boss extends into the inner cavity of the rod piece; the inner wall of the cutting end of the rod piece is provided with an inner inclined plane which expands outwards, and the boss is provided with an outer inclined plane which is matched with the inner inclined plane. When the cutting head is in the closed position, the outer inclined surface is attached to the inner inclined surface to seal the inner cavity of the rod piece.

After the boss stretches into the inner cavity of the rod piece, the connection strength of the cutting head and the rod piece in the radial direction can be enhanced, the phenomenon that the cutting head is separated from the rod piece in the construction process is avoided, after the inner inclined plane and the outer inclined plane which can be mutually attached are arranged, in the construction process, under the bidirectional pushing of the rod piece and a soil body, the cutting head can be attached to the rod piece very tightly, the connection strength between the cutting head and the rod piece is facilitated, the inner cavity of the rod piece can be sealed by the cutting head, the amount of the soil body entering the inner cavity of the rod piece is reduced to the maximum extent, and the blockage of the inner cavity of the rod piece by the soil body is avoided.

Further, in order to enable the excavated earthwork to be smoothly conveyed upwards and sent out of the ground, a spiral sheet is formed on the outer wall of the cutting end of the rod piece, and one end of the spiral sheet facing the cutting end extends outwards along the axial direction out of the end face of the cutting end to form an end face cutting knife. After the end face cutting blades are formed at the tail ends of the spiral sheets, the cutting of soil bodies can be enhanced, and cut earthwork can move upwards along the end face cutting blades and enter the grooves among the spiral sheets to move upwards.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a front view of fig. 1.

Fig. 3 is a schematic view of the cutting head after it has been opened.

FIG. 4 is a schematic view of the reamer blade after opening at the reamer position.

Fig. 5 is a view along B-B in fig. 4.

Fig. 6 is a view along a-a in fig. 4.

Fig. 7 is a schematic view of the auger stem with the reamer bit installed.

Detailed Description

Referring to fig. 1 and 2, a reamer bit 100 includes a shaft 11 and a cutting head 20, the shaft 11 extending along an axis 101 and having a cylindrical outer peripheral surface. One end of the rod 11 is formed as a flared end 113 and the other end of the rod is formed as a cutting end 114, a cutting head 20 being mounted at the cutting end 114 of the rod, the cutting head 20 being for cutting the earth mass. At least one reaming blade 51 is arranged on the outer peripheral surface of the reaming end 113 of the rod piece, one end of the reaming blade 51 is connected to the outer peripheral surface of the rod piece through a blade hinge joint 53, and the other end of the reaming blade 51 is a free end; via the blade hinge 53, the reamer blade 51 is able to rotate between the locked position and the reamed position. In fig. 1 and 2, reamer blade 51 is in the locked position and in fig. 4 reamer blade 51 is in the reamer position.

Specifically, in this embodiment, two rows of reaming blades are provided along the axis direction, each row of reaming blades has three reaming blades, and the reaming blades in the same row are annularly arranged on the outer peripheral surface of the rod member.

A first helical blade 12 is mounted on the outer peripheral surface of the cutting end 114 of the rod; when the reaming blades 51 are located at the reaming site, the radius of rotation of the reaming blades 51 is greater than the radius of rotation of the first helical blade 12 and the cutting head 20; in fig. 5, reference numeral 519 denotes the cutting edge of the reamer blade 51 in the radial direction when the reamer blade is in the reamer position.

When the hole expanding drill bit rotates forwards, the hole expanding drill bit can drill downwards, and the hole expanding blades are located at the locking position; when the reamer head is rotated in reverse, the reamer blades are rotated from the locked position to the reaming position by centrifugal force. The direction indicated by the arrow N in fig. 5 is the direction in which the reamer head rotates forward.

The reamer blade 51 is arcuate and, when deployed, is a rectangular plate that rests against the outer peripheral surface of the rod when the reamer blade is in the locked position.

To avoid wear to the reamer blades during operation, an annular projection 54 is formed on the stem, the annular projection 54 being formed by the outer circumferential surface of the stem projecting radially outwardly, a recess 52 being formed in the annular projection 54, a recess 52 being provided for each reamer blade 51, the reamer blade being mounted in the corresponding recess, the outer side 513 of the reamer blade not extending outwardly beyond the outer surface 116 of the annular projection 54 when the reamer blade is in the locked position.

Referring to fig. 1, after the groove 52 is formed on the annular protrusion 54, an upper side 541, a middle side 542, and a lower side 543 are sequentially formed along the axial direction, the upper side 541, the middle side 542, and the lower side 543 are all circular rings surrounding the outer circumferential surface of the rod, three first vertical plates 544 are formed between the upper side 541 and the middle side 542 along the axial direction, three second vertical plates 545 are formed between the middle side 542 and the lower side 543 along the axial direction, the first vertical plates 544 divide the annular groove between the upper side 541 and the middle side 542 into three grooves 52, and the second vertical plates 545 divide the annular groove between the middle side 542 and the lower side 543 into three grooves 52. In this embodiment, in the axis direction, each first vertical plate is vertically opposite to one second vertical plate. The screw 531 penetrates the upper side 541, the middle side 542 and the lower side 543 in sequence and is locked by a nut 532, and the screw 531 and the nut 532 together form a blade hinge 53. One end of the reamer blade 51 is formed with a mounting hole 512, and the reamer blade 51 is rotatably mounted on the screw 531 through the mounting hole 512.

When the reamer blade is in the locked position, a small inside large wedge slot 55 is formed between the end surface 511 of the free end of the reamer blade and the inside surface of the recess 52.

In this embodiment in particular, the end face of the free end of the reamer blade is inclined in the direction of extension radially outwards, away from the inner side of the groove opposite thereto, when the reamer blade is in the locked position. Referring now to fig. 5 for explanation, in fig. 5, one of the two rows of reamer blades is shown, and the three reamer blades in the row of reamer blades are, in order, a first reamer blade 516, a second reamer blade 517 and a third reamer blade 518, wherein the first reamer blade 516 is in the locked position and the second reamer blade 517 and the third reamer blade 518 are in the reamer position. The end face 511 of the free end of the first reamer blade is inclined in a radially outwardly extending direction away from the inner face 522 of the recess opposite thereto. It will be appreciated that in other embodiments the end face 511 of the free end of the first reamer blade may also extend in a radially outward direction.

The inner side of the groove facing the reamer blade in this embodiment is inclined in a direction extending radially outwardly away from the reamer blade. Continuing with FIG. 5, in FIG. 5, the inner side surface 522 of the groove is the inner side surface facing the reamer blade, and the inner side surface 522 extends radially outward and is angled away from the reamer blade. It will be appreciated that in other embodiments the inner side of the groove facing the reamer blade may also extend in a radially outward direction.

The rod 11 in this embodiment is embodied as a hollow tube extending along the axis 101, i.e. the rod 11 has a lumen 115 extending along the axis and through the end faces of the two ends of the rod.

The cutting head 20 is connected to the cutting end of the rod via a cutting head hinge 30, the cutting head 20 being rotatable between an open position and a closed position via the cutting head hinge 30; under the action of external force, the cutting head can rotate from the closed position to the open position. In fig. 1 and 2, the cutting head is in a closed position, and in fig. 3, the cutting head is in an open position.

The cutting head 20 has a body 21 having a body inner side 26 and a body outer side 27 opposite to the body inner side 26, the body inner side 26 of the body abutting against the end face of the cutting end of the rod when the cutting head 20 is in the closed position; when the cutting head is in the open position, the cutting head does not enclose the inner cavity of the stem, as viewed in the direction of the axis of the stem, with a passageway between the inner cavity of the stem and the cutting head. In fig. 3, the cutting head 20 is in a freely hanging position under the action of gravity, and the cutting head 20 is in a fully open position, so that the inner cavity of the rod 11 has a larger open position.

A cutting blade 22 for cutting soil is formed on the body outer side surface 27 of the body, and a blade 222 of the cutting blade 22 protrudes from the body outer side surface 27 of the body.

In this embodiment, four cutting blades are formed on the body outer side surface 27 of the body 21, and when the cutting head is in the closed position, the cutting blades are elongated and extend in the radial direction of the rod, and the distance from the cutting edge of each cutting blade to a first plane 102 perpendicular to the axis 101 and cutting the rod is gradually reduced from the central portion of the body toward the edge of the body. The four cutting blades are radially arranged on the outer side surface of the body by taking the central part of the body as a center, namely the four cutting blades are symmetrically arranged on the outer side surface of the body. The inner end of the cutting insert has a greater distance than the outer end with respect to the first plane 102.

In this embodiment, four cutting blades are provided, and one ends of the four cutting blades 22 facing the central portion of the body are connected together to form one common end 223. The cutting blades are connected at the central portion of the body to form one cutting blade in appearance, but the cutting blades are also an aggregate of a plurality of cutting blades. Of course in other embodiments the ends of the cutting inserts towards the central portion of the body may not be connected together, i.e. there may be no common end portion.

It can be understood that in other embodiments, only two cutting blades may be provided, and the two cutting blades are symmetrically arranged, so that when the cutting blades cut soil, a relatively uniform moment can be formed on the body. The cutters in this embodiment are arranged along a circular ring, it being understood that when the body of the cutting head is large, the cutters may be arranged along two circular rings, each ring being provided with a different number of cutters. Of course in other embodiments the cutting blade may be provided with three, four or more turns.

Referring to fig. 2, each cutting blade is provided with at least two tooth grooves 221, each tooth groove 221 penetrates through the cutting blade edge 222 along the thickness direction of the cutting blade, and the tooth grooves on each cutting blade are arranged at intervals along the extension direction of the cutting blade.

Referring to fig. 3 and 6, a boss 25 is formed on the inner side 26 of the body and extends into the inner cavity of the rod when the cutting head is in the closed position; the inner wall 111 of the cutting end of the rod is formed with an inner inclined surface 112 which is outwardly enlarged, and the inner inclined surface 112 is inclined so as to be gradually enlarged from the inside to the outside. The boss has an outer inclined surface 251 which conforms to the inner inclined surface 112 described above. When the cutting head is covered on the rod piece, the inner inclined plane 112 is attached to the outer inclined plane 251, so that the body of the cutting knife is tightly bonded on the hollow pipe when the cutting knife cuts soil, the loosening of the cutting head is avoided, and the external soil can be effectively prevented or reduced from entering the hollow pipe. A recess 252 is formed in the boss 25 to be depressed toward the outer side surface of the body.

Specifically, in the present embodiment, the inner inclined surface 112 is a tapered surface, the taper α of the inner inclined surface 112 is 12 °, the outer inclined surface 251 is also a tapered surface, and the taper β of the outer inclined surface is 12 °, that is, the inner inclined surface 112 and the outer inclined surface 251 have the same inclination, so as to form a closer fit. In other embodiments, the taper of the inner inclined surface 112 and the taper of the outer inclined surface 251 may be different angles, and of course, the inclination of the inner inclined surface and the inclination of the outer inclined surface may be different as long as a relatively close combination can be formed. In addition, in other embodiments, the inner inclined surface and the outer inclined surface may also be pyramidal surfaces or elliptical in cross section.

In this embodiment, a first mounting lug 15 is disposed on the outer edge of the cutting end 114 of the rod member, two second mounting lugs 23 are disposed on the outer edge of the cutting head body 21 at intervals, the first mounting lug 15 is clamped between the two second mounting lugs 23, the second mounting lug 23 and the first mounting lug 15 are connected together by a pin 31, and the first mounting lug 15, the second mounting lug 23 and the pin 31 together form the cutting head hinge 30.

The cutting end 114 of the rod 11 is provided with a first fixing lug 16, the first fixing lug 16 is provided with a first pin hole 161, the body 21 of the cutting head is provided with two second fixing lugs 24 at intervals, the second fixing lug 24 is provided with a second pin hole 241, the first fixing lug 16 can be inserted between the two second fixing lugs 24 and inserted into the second pin hole 241 and the first pin hole 161 by pins, and the cutting head 20 is fixed on the hollow tube so as to be convenient for transportation and storage. During construction, there is no connection between the first and second fixing lugs 16 and 24 so that the cutting head 20 can be separated from the hollow tube. However, in other embodiments, the first and second fixing lugs may be eliminated, and the use of the reamer bit is not affected after the first and second fixing lugs are eliminated, and the cutting head needs to be fixed to the rod by using a rope or other binding objects during transportation and storage, so as to avoid unnecessary damage to the cutting head.

The end of the first helical blade 12 facing the cutting end 114 extends axially outward beyond the end face of the cutting end to form an end face cutter 13, the end face cutter 13 is provided with an end face groove 132, and the end face groove 132 penetrates through an end face blade 131 of the end face cutter.

Referring to fig. 7, the reamer head 100 of the present embodiment is mounted on the lower end of the auger stem 200, the reamer head 100 and the auger stem 200 together form an auger stem, the auger stem 200 includes a stem body 210 and stem body spiral pieces 220 surrounding the outer circumferential surface of the stem body 210, the stem body 210 has a through hole 230 penetrating the end surfaces of both ends of the stem body, and the through hole 230 communicates with the inner cavity 115 of the stem 11. The upper end of the rod body is provided with a gear 240, and the motor drives the auger stem to rotate through the gear 240.

A first flange 14 is installed at the end of the reaming end 113 of the rod 11, a second flange 250 is installed at the lower end of the rod body 210, and the reaming bit 100 is fixedly connected to the screw rod 200 through the first flange 14 and the second flange 250.

During drilling, firstly, the auger stem is rotated forwards to form a straight tubular pile hole, in the forward rotation process, under the compression of an external soil body, the reaming blades 518 are kept in the grooves and located at the locking position, after the set depth is reached, the auger stem is rotated backwards, under the action of centrifugal force and the obstruction of a soil body on the peripheral wall of the drilled hole, the reaming blades are rotated to the reaming position to keep the auger stem to rotate backwards, the auger stem is lifted upwards, and reaming construction is completed.

The anchor cable can be inserted into the pile hole from one end 201 of the through hole 230 of the rod body, which is far away from the reamer bit, concrete or cement soil is injected into the pile hole through the through hole 230, and the drill rod is pulled out of the pile hole, so that the purpose of installing the anchor cable can be achieved without pulling the drill rod out of the pile hole. The channel formed by the through-hole 230 of the rod body and the inner cavity 115 of the hollow tube can be used as a pouring channel for concrete or cement. In order to avoid that concrete or cement causes great abrasion to the inner wall of the rod body and the inner wall of the hollow tube as the rod body in the pouring process and influences the service life, the grouting pipe can be inserted into the channel formed by the through hole 230 of the rod body and the inner cavity 115 of the hollow tube, and cement paste or cement is injected into the drilled hole through the grouting pipe.

Of course, the reamer bit in this embodiment may also be mounted on a screw rod without a through hole for forming a pile hole and performing reaming.

Claims

1. A hole expanding drill bit is characterized by comprising a rod piece and a cutting head, wherein the rod piece extends along an axis and is provided with a cylindrical outer peripheral surface; at least two reaming blades are arranged on the peripheral surface of the reaming end of the rod piece, one end of each reaming blade is connected to the peripheral surface of the rod piece through a blade hinge piece, and the other end of each reaming blade is a free end; the reaming blade is rotatable between a locked position and a reaming position via the blade hinge; a first helical blade is arranged on the peripheral surface of the cutting end of the rod piece; when the reaming blade is positioned at the reaming position, the rotating radius of the reaming blade is larger than the rotating radius of the first helical blade and the cutting head;

2. The reamer bit of claim 1, wherein an annular projection is formed on the outer peripheral surface of the stem, a groove is formed on the annular projection so as to be recessed in the radial direction, and the reamer blade is fitted in the groove so that the outer side surface of the reamer blade does not extend outward beyond the outer surface of the annular projection when the reamer blade is in the locked position.

3. The reamer bit of claim 2, wherein the end surface of the free end of the reamer blade and the inside surface of the recess form a wedge-shaped groove therebetween when the reamer blade is in the locked position.

4. A reamer bit according to claim 2, wherein the end surface of the free end of the reamer blade is inclined in a radially outward extending direction away from the inner side surface of the recess opposite thereto or extends in a radially outward direction when the reamer blade is in the locked position.

5. The reamer bit of claim 2, wherein the inner side of the recess facing the reamer blade is inclined in a direction extending radially outwardly, away from the reamer blade, or the inner side of the recess facing the reamer blade extends in a direction extending radially outwardly when the reamer blade is in the locked position.

6. The reamer bit of claim 1, wherein the rod member has an interior cavity extending along the axis and through end faces of the ends of the rod member, the cutting head being connected to the cutting end of the rod member via a cutting head hinge, the cutting head being rotatable between the open position and the closed position via the cutting head hinge; under the action of external force, the cutting head can rotate from a closed position to an open position;

7. The reamer bit of claim 6,

at least two cutting knives are formed on the outer side surface of the body, and the at least two cutting knives are radially arranged on the outer side surface of the body by taking the central part of the body as the center;

8. The reamer bit of claim 7, wherein at least two gullets are provided in at least one of the blades, each gullet extending through the cutting edge of the blade in the thickness direction of the blade, the at least two gullets in any one of the blades being spaced apart in the direction of extension of the blade.

9. The reamer bit of claim 6, wherein a boss is formed on the inside surface of the body, the boss extending into the interior cavity of the stem when the cutting head is in the closed position;

the inner wall of the cutting end of the rod piece is provided with an inner inclined plane which expands outwards, and the boss is provided with an outer inclined plane which is matched with the inner inclined plane.

10. The reamer bit of claim 5, wherein a helical blade is formed on an outer wall of the cutting end of the stem, the helical blade forming an end cutting blade after an end of the helical blade facing the cutting end extends axially outward beyond an end face of the cutting end.