Diameter expanding device for variable-diameter cast-in-place pile construction drill bit

Abstract

The utility model discloses a diameter expanding device for a variable-diameter cast-in-place pile construction drill bit. The diameter expanding device comprises a connector, a spiral blade, a core pipe, a concrete pouring pipe, a lug seat, a shaft I, a drill tip assembly and cutting teeth. The expanding device comprises a hollow oil cylinder, an expanding body, a shaft II and a guide connecting device; a cylinder body of the hollow oil cylinder is fixed on the inner wall of the core pipe; the concrete filling pipe penetrates through an inner hole cavity of a piston pipe of the hollow oil cylinder; the expanding body comprises an upper body and a lower body which are fastened through a bolt, the outer side of the upper end of the upper body is hinged to a seat body arranged on the wall of the core tube through a shaft II, and the inner side of the upper end of the upper body is connected with the lower end of a piston tube of the hollow oil cylinder through a guide connecting device. Openings allowing the expanding body to pass through in a rotating mode are formed in the positions, corresponding to the expanding body, of the core pipe and the spiral blades, and the piston pipe moves up and down to drive the expanding body to rotate around the shaft II. The drill bit is high in drilling efficiency, good in concrete pouring smoothness, capable of achieving various expanding amounts and low in use cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of drill bit for building pile construction, especially relates to a diameter expansion device suitable for drill bit for variable-diameter bored pile construction. BACKGROUND

[0002] In building pile foundation, variable-diameter bored pile accounts for a large share, which has the advantages of wide adaptability to geological conditions, high pile bearing capacity, and low pile foundation cost. The construction of variable-diameter bored pile usually adopts a drill bit with a diameter expansion function to expand the hole and pressurize the pile by pulling out the drill bit, wherein the diameter expansion device in the construction drill bit is mostly driven by a hydraulic cylinder, which is usually fixed outside the drill bit core pipe and between the spiral blades, or fixed on the concrete pouring channel in the inner cavity of the drill bit core pipe, causing many troubles in construction: ① The oil cylinder fixed outside the drill bit core pipe and between the spiral blades is not conducive to the transmission of the cut soil, affecting the drilling efficiency; secondly, the exposed section of the oil cylinder piston rod has no reliable dustproof and anticorrosive measures, reducing the service life of the oil cylinder. ② The oil cylinder fixed on the concrete pouring channel in the inner cavity of the drill bit core pipe hinders the smoothness of the concrete pouring channel, causing blockage; secondly, the exposed section of the oil cylinder piston rod is corroded by concrete, and the oil cylinder seal is damaged and leaks when the piston rod is solidified with cement slurry, even causing damage to the oil cylinder.

[0003] In addition, the drill bit for variable-diameter bored pile construction has a fixed expansion amount, and the expansion body in the drill bit is an integral whole, so for the same designed pile diameter and different expansion amounts of pile type, the corresponding expansion amount of drill bit needs to be replaced, resulting in an increase in the number of drill bits and large capital investment; at the same time, the expansion body wears out beyond the specified size during expansion construction, and a new expansion body needs to be replaced, causing waste of the entire expansion body. UTILITY MODEL CONTENTS

[0004] In view of the above problems of the installation position of the oil cylinder in the drill bit, the expansion amount of the expansion body, and the high-cost wear replacement of the expansion body, the utility model provides a diameter expansion device for variable-diameter bored pile construction drill bit, which has high drilling efficiency, good concrete pouring smoothness, can realize multiple expansion amounts, and has low use cost.

[0005] The utility model discloses a technical scheme is: the drilling head for variable diameter cast-in-place pile construction is expanded in diameter device, including joint, spiral blade, core pipe, concrete pouring pipe, ear seat, axle I, drill tip assembly and cutting tooth, be equipped with expanding device, the expanding device includes hollow oil cylinder, expanding body, axle II and guiding connecting device, the cylinder body of hollow oil cylinder is fixed on the inner wall of core pipe, and the concrete pouring pipe is through the piston pipe inner hole cavity of hollow oil cylinder, the expanding body includes upper body and lower body, and the upper body and lower body pass through bolt fastening, and the upper body upper end outside is through axle II and is hinged to the seat body that sets up on the core pipe wall, and the upper end inboard of upper body is connected with the piston pipe lower end of hollow oil cylinder through guiding connecting device, and the core pipe and spiral blade on the position corresponding with expanding body all are equipped with the opening that can rotate through for expanding body, and the piston pipe goes up and down and drives expanding body to rotate around axle II.

[0006] Further, the expanding body includes L-shaped upper body I and lower body I, the upper end arm of L-shaped upper body I is circular ring, the hollow inner core is used for the concrete pouring pipe to pass and is gap fit, the outer edge of the upper end arm of L-shaped upper body I is equipped with U-shaped notch, the upper end outside of L-shaped upper body I is hinged to the seat body that sets up on the core pipe wall through axle II, and the lower end arm of L-shaped upper body I is fastened with lower body I through bolt, the guiding connecting device includes plate seat I and connecting plate I, one end of plate seat I is fixed with the piston pipe lower end of hollow oil cylinder, and the other end is hinged to one end of connecting plate I through pin, and the other end of connecting plate I is hinged to the U-shaped notch of L-shaped upper body I through pin, and the core pipe and spiral blade are equipped with the notch for the up and down movement of connecting plate I at the position corresponding with connecting plate I, and the gap of the core pipe is closed in the position corresponding with connecting plate I.

[0007] Further, there is a top rod I, the upper end of top rod I is hinged to the ear plate that sets up at the lower end of connecting plate I through pin, and the bottom end of top rod I passes through the hole that is arranged on the bottom surface of the core pipe bottom end and an ear seat and abuts on the upper end face of the corresponding side of drill tip assembly in the state of closing concrete channel mouth, in the process of rotating out of expanding body, top rod I goes down and pushes drill tip assembly to rotate around axle I, and opens concrete channel mouth.

[0008] Further, when expanding body is in the state of retraction, the maximum outer edge of expanding tooth I at the lower end of lower body I is in the column face formed by spiral blade, or on the column face formed by spiral blade, or outside the column face formed by spiral blade.

[0009] Further, the expanding body includes upper body II and lower body II, the upper end of upper body II is cylindrical, the upper end of upper body II is hinged to the seat body that sets up on the core pipe wall through axle II, the inner side of the upper end of upper body II is equipped with tooth, and the lower end of upper body II is fastened with lower body II through bolt, the guiding connecting device includes rack, and the lower end of piston pipe of hollow oil cylinder is fixed with rack, and the tooth is engaged with rack.

[0010] Further, the plate seat II is arranged on the lower end of the hollow cylinder, and the upper end of the top rod II is connected with the plate seat II, the bottom end of the top rod II passes through the hole arranged on the bottom surface of the ear seat and abuts against the upper end surface of the drill tip assembly corresponding to the closed concrete channel, and the top rod II drives the drill tip assembly to rotate around the shaft I and opens the concrete channel during the rotating of the expanding body.

[0011] Further, the maximum outer edge of the expanding teeth II at the lower end of the lower body II is in, on or out of the column surface formed by the helical blade when the expanding body is in the retracted state.

[0012] Further, the expanding body comprises an upper body III and a lower body III, the upper end of the upper body III is in a cylindrical shape, the upper end of the upper body III is hinged with the seat body arranged on the wall of the core pipe through the shaft II, the middle part of the upper body III is provided with a recess, and the lower end of the upper body III is fastened with the lower body III through bolts.

[0013] Further, the plate seat IV is arranged on the lower end of the hollow cylinder, and the upper end of the top rod III is connected with the plate seat IV, the bottom end of the top rod III passes through the hole arranged on the bottom end of the core pipe and the bottom surface of the ear seat and abuts against the upper end surface of the drill tip assembly corresponding to the closed concrete channel, and the top rod III drives the drill tip assembly to rotate around the shaft I and opens the concrete channel during the rotating of the expanding body.

[0014] Further, the maximum outer edge of the expanding teeth III at the lower end of the lower body III is in, on or out of the column surface formed by the helical blade when the expanding body is in the retracted state.

[0015] The beneficial effects of the utility model are as follows:

[0016] 1. The hollow cylinder of the expanding device is arranged in the annular cavity formed by the core pipe and the concrete pouring pipe, is sealed well and can guarantee the normal use of the oil cylinder.

[0017] 2. The concrete pouring channel of the drill bit is unobstructed, and the phenomenon of blockage caused by the installation position of the oil cylinder is avoided.

[0018] 3. The utility model has high efficiency of uploading the soil body when the drill bit drills, avoids the adverse effect of the expanding device on the uploading of the soil body and shortens the time of hole and pile forming.

[0019] 4. The utility model discloses, the expansion body adopts the assembled structure, can satisfy one drill head can construction the expansion pile section of different outer diameter requirement of forming hole and forming pile by replacing the lower body, also convenient for replacing the lower body of wearing failure, reduce the cost of construction drill head.

[0020] 5. The utility model discloses, the expansion device can be equipped with the top rod, is favorable to the opening of drill tip assembly, guarantees the smooth filling of pressure grouting concrete into the pile hole, avoids the blockage caused by the drill tip assembly not to open, also reduces the virtual soil quantity of pile bottom.

[0021] 6. The utility model discloses the drill bit with expansion device, can construction various cast-in-place pile type, the pile body can have the pile type of two or more combinations in column body pile section, screw thread pile section, expansion column body pile section, expansion screw thread pile section, complex extrusion expansion column body pile section, complex extrusion expansion screw thread pile section, provides support for optimization design. DRAWINGS

[0022] Figure 1 It is the expansion device main view schematic drawing of the diameter change cast-in-place pile construction drill bit of the utility model embodiment 1.

[0023] Figure 2 It is Figure 1 The side view (expansion body retraction state).

[0024] Figure 3 It is Figure 1 The side view (expansion body spin-out state).

[0025] Figure 4 It is Figure 2 The A-A section view in

[0026] Figure 5 It is the expansion body main view schematic drawing of the diameter change cast-in-place pile construction drill bit of embodiment 1 expansion device.

[0027] Figure 6 It is Figure 5 The top view schematic drawing of

[0028] Figure 7 It is Figure 5 The side view schematic drawing of

[0029] Figure 8 It is the expansion device main view schematic drawing of the diameter change cast-in-place pile construction drill bit of the utility model embodiment 2.

[0030] Figure 9 It is Figure 8 The side view (expansion body retraction state) of

[0031] Figure 10 It is Figure 8 The side view (expansion body spin-out state) of

[0032] Figure 11 is the main view schematic diagram of the diameter expansion device for variable-diameter cast-in-place pile construction drill bit of the embodiment 3 of the utility model.

[0033] Figure 12 is Figure 11 the side view (the diameter expansion body retraction state).

[0034] Figure 13 is Figure 11 the side view (the diameter expansion body spin-out state).

[0035] Figure 14 is Figure 13 the B-B section view in the.

[0036] Figure 15 is the main view schematic diagram of the diameter expansion device for variable-diameter cast-in-place pile construction drill bit of the embodiment 4 of the utility model.

[0037] Figure 16 is Figure 15 the side view (the diameter expansion body retraction state).

[0038] Figure 17 is Figure 15 the side view (the diameter expansion body spin-out state). DETAILED DESCRIPTION

[0039] Embodiment 1

[0040] As Figures 1-7 shown, a diameter expansion device for variable-diameter cast-in-place pile construction drill bit, including joint (1), spiral blade (2), core pipe (3), concrete pouring pipe (5), ear seat (6), shaft I (7), drill tip assembly (8), cutting tooth (9) and diameter expansion device.

[0041] The lower end of joint (1) and the upper end of core pipe (3) are firmly combined into one body concentrically, the lower end of core pipe (3) is provided with two groups of one-dimensional symmetrically arranged ear seats (6), spiral blade (2) is spirally wound on the outer surface of joint (1) and core pipe (3), the bottom end of spiral blade (2) is provided with cutting tooth (9). Concrete pouring pipe (5) is located in the inner cavity of core pipe (3) and is arranged concentrically with core pipe (3), the upper end thereof is combined with the lower end of joint (1), and the lower end thereof is combined with the bottom end of core pipe (3), forming a smooth concrete pouring channel; both ends of drill tip assembly (8) are placed in two ear seats (6) and one end is hinged to an ear seat (6) through shaft I (7), drill tip assembly (8) rotates around shaft I (7), closes or opens the concrete pouring channel of the drill bit.

[0042] The diameter expansion device includes hollow oil cylinder (101), diameter expansion body, shaft II (103), guide connecting device and top rod I (117).

[0043] The cylinder body of the hollow oil cylinder (101) is fixed on the inner wall of the core pipe (3), and the concrete pouring pipe (5) penetrates the inner hole of the piston pipe (102) of the hollow oil cylinder (101) and is in clearance fit with the inner hole of the piston pipe.

[0044] The diameter-expanding body comprises an L-shaped upper body I (111) and a lower body I (112). The upper end arm of the L-shaped upper body I (111) is in the form of a circular ring, and an inner core (113) is provided in the L-shaped upper body I (111) for the concrete pouring pipe (5) to pass through and be in clearance fit. A U-shaped notch (114) is provided on the outer edge of the upper end arm of the L-shaped upper body I (111). The L-shaped upper body I (111) is hinged to a seat body (104) provided on the wall of the core pipe (3) through a shaft II (103) on the outer side of the upper end of the L-shaped upper body I (111). The lower end arm of the L-shaped upper body I (111) is fastened to the lower body I (112) by bolts to form an integral body. Openings are provided on the core pipe (3) and the spiral blade (2) at positions corresponding to the diameter-expanding body, so that the diameter-expanding body can rotate through the center of the drill bit. The piston pipe (102) drives the diameter-expanding body to rotate around the shaft II (103) by moving up and down, so as to realize the retraction and opening of the diameter-expanding body.

[0045] The guide connecting device comprises a plate seat I (115) and a connecting plate I (116). One end of the plate seat I (115) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), and the other end is hinged to one end of the connecting plate I (116) through a pin. The other end of the connecting plate I (116) is hinged to the U-shaped notch (114) of the L-shaped upper body I (111) through a pin. Notches are provided on the core pipe (3) and the spiral blade (2) at positions corresponding to the connecting plate I (116), so that the connecting plate I (116) can move up and down. The core pipe (3) is closed by a shield plate (4) at a position corresponding to the connecting plate I (116).

[0046] The upper end of a top rod I (117) is hinged to an ear plate (118) provided on the lower end of the connecting plate I (116) through a pin. The bottom end of the top rod I (117) penetrates a hole provided on the bottom end of the core pipe (3) and the bottom surface of an ear seat (6) and abuts against the upper end surface of the corresponding side of a drill tip assembly (8) in a state of closing the concrete passage. In the process of rotating out the diameter-expanding body, the top rod I (117) moves downward to drive the drill tip assembly (8) to rotate around the shaft I (7) and open the concrete passage.

[0047] As a preferred embodiment, in the retracted state of the diameter-expanding body, the maximum outer edge of the diameter-expanding teeth I (119) at the lower end of the lower body I (112) is on the cylindrical surface formed by the spiral blade (2). Of course, in the retracted state of the diameter-expanding body, the maximum outer edge of the diameter-expanding teeth I (119) at the lower end of the lower body I (112) can also be inside or outside the cylindrical surface formed by the spiral blade (2).

[0048] Embodiment 2

[0049] As Figures 8-10As shown in the figure, a diameter expansion device for a variable-diameter cast-in-place pile construction drill bit includes a joint (1), a spiral blade (2), a core pipe (3), a concrete pouring pipe (5), an ear seat (6), a shaft I (7), a drill tip assembly (8), a cutting tooth (9), and a diameter expansion device.

[0050] Other structures are exactly the same as those of Embodiment 1, except that this embodiment does not have a top rod I (117) and an ear plate (118).

[0051] Embodiment 3

[0052] As Figures 11-14 shown in the figure, a diameter expansion device for a variable-diameter cast-in-place pile construction drill bit includes a joint (1), a spiral blade (2), a core pipe (3), a concrete pouring pipe (5), an ear seat (6), a shaft I (7), a drill tip assembly (8), a cutting tooth (9), and a diameter expansion device.

[0053] The lower end of the joint (1) is firmly combined with the upper end of the core pipe (3) in the center to form an integral whole, the lower end of the core pipe (3) is provided with two groups of linearly symmetrical and spaced apart ear seats (6), the spiral blade (2) is spirally wound on the outer surfaces of the joint (1) and the core pipe (3), and the bottom end of the spiral blade (2) is provided with a cutting tooth (9). The concrete pouring pipe (5) is located in the inner cavity of the core pipe (3) and is arranged concentrically with the core pipe (3), the upper end thereof is combined with the lower end of the joint (1), and the lower end thereof is combined with the bottom end of the core pipe (3), forming a smooth concrete pouring channel; the two ends of the drill tip assembly (8) are placed in the two ear seats (6) on the upper side, one end thereof is hinged to one ear seat (6) through a shaft I (7), the drill tip assembly (8) rotates around the shaft I (7), and the concrete pouring channel of the drill bit is closed or opened.

[0054] The diameter expansion device includes a hollow oil cylinder (101), a diameter expansion body, a shaft II (103), a guide connecting device, and a top rod II (126).

[0055] The cylinder body of the hollow oil cylinder (101) is fixed on the inner wall of the core pipe (3), and the concrete pouring pipe (5) penetrates through the inner hole cavity of the piston pipe (102) of the hollow oil cylinder (101) and is in clearance fit with the inner hole cavity of the piston pipe.

[0056] The diameter-expanding body comprises an upper body II (121) and a lower body II (122). The upper end of the upper body II (121) is cylindrical. The upper end of the upper body II (121) is hinged to a seat body (104) arranged on the wall of the core pipe (3) through a shaft II (103). A tooth (123) is arranged on the inner side of the upper end of the upper body II (121). The lower end of the upper body II (121) is fastened to the lower body II (122) through a bolt. The core pipe (3) and the spiral blade (2) at the position corresponding to the diameter-expanding body are each provided with an opening through which the diameter-expanding body can rotate. The rotation plane of the diameter-expanding body around the shaft II (103) passes through the center of the drill bit. The upward and downward movement of the piston pipe (102) drives the diameter-expanding body to rotate around the shaft II (103), so as to realize the retraction and opening of the diameter-expanding body.

[0057] The guide connecting device comprises a rack (124) fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101). The tooth (123) is engaged with the rack (124). During the downward movement of the piston pipe of the hollow oil cylinder, the rack-tooth engagement pair drives the diameter-expanding body to rotate outward.

[0058] The plate seat II (125) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101). The top rod II (126) is connected to the plate seat II (125). The bottom end of the top rod II (126) passes through the hole arranged on the bottom surface of the core pipe (3) and an ear seat (6) and abuts against the upper end surface of the corresponding side of the drill tip assembly (8) in the closed concrete passage port state. During the rotation of the diameter-expanding body, the top rod II (126) moves downward to drive the drill tip assembly (8) to rotate around the shaft I (7), so as to open the concrete passage port.

[0059] As a preferred embodiment, in the retracted state of the diameter-expanding body, the maximum outer edge of the diameter-expanding tooth II (127) at the lower end of the lower body II (122) is in the cylindrical surface formed by the spiral blade (2). Of course, in the retracted state of the diameter-expanding body, the maximum outer edge of the diameter-expanding tooth II (127) at the lower end of the lower body II (122) can also be on or outside the cylindrical surface formed by the spiral blade (2).

[0060] Embodiment 4

[0061] As shown in Figures 15-17 A diameter-expanding device for a variable-diameter cast-in-place pile construction drill bit, which comprises a joint (1), a spiral blade (2), a core pipe (3), a concrete pouring pipe (5), an ear seat (6), a shaft I (7), a drill tip assembly (8), a cutting tooth (9), and a diameter-expanding device.

[0062] The lower end of the joint (1) is fixedly combined with the upper end of the core pipe (3) in the center, the lower end of the core pipe (3) is provided with two groups of ears (6) arranged in a one-dimensional symmetry, the spiral blade (2) is spirally wound on the outer surface of the joint (1) and the core pipe (3), and the bottom end of the spiral blade (2) is provided with a cutting tooth (9). The concrete pouring pipe (5) is located in the inner cavity of the core pipe (3) and is arranged in the center with the core pipe (3), the upper end thereof is combined with the lower end of the joint (1), the lower end thereof is combined with the annular stop plate at the bottom end of the core pipe (3), and a smooth concrete pouring channel is formed; the two ends of the drill tip assembly (8) are arranged in the two ears (6) on the upper side, one end thereof is hinged with one ear (6) through a shaft I (7), the drill tip assembly (8) rotates around the shaft I (7), and the concrete pouring channel of the drill bit is closed or opened.

[0063] The diameter expansion device comprises a hollow oil cylinder (101), a diameter expansion body, a shaft II (103), a guide connecting device and a top rod III (137).

[0064] The cylinder body of the hollow oil cylinder (101) is fixed on the inner wall of the core pipe (3), and the concrete pouring pipe (5) penetrates through the inner hole cavity of the piston pipe (102) of the hollow oil cylinder (101) and is in a gap fit with the inner hole cavity of the piston pipe.

[0065] The diameter expansion body comprises an upper body III (131) and a lower body III (132), the upper end of the upper body III (131) is in a cylindrical shape, the upper end of the upper body III (131) is hinged with a seat body (104) arranged on the wall of the core pipe (3) through the shaft II (103), the middle part of the upper body III (131) is provided with a groove (133), and the lower end of the upper body III (131) is fastened with the lower body III (132) through bolts. The core pipe (3) and the spiral blade (2) at the position corresponding to the diameter expansion body are each provided with an opening through which the diameter expansion body can rotate, the rotation surface of the diameter expansion body around the shaft II (103) passes through the center of the drill bit, the piston pipe (102) moves up and down to drive the diameter expansion body to rotate around the shaft II (103), and the diameter expansion body is retracted and opened.

[0066] The guide connecting device comprises a plate seat III (134) and a connecting plate III (135), one end of the plate seat III (134) is fixed with the lower end of the piston pipe (102) of the hollow oil cylinder (101), the other end is hinged with one end of the connecting plate III (135) through a pin, the other end of the connecting plate III (135) is inserted into the groove (133) and is hinged with the upper body III (131) through a pin. During the downward movement of the piston pipe of the hollow oil cylinder, the diameter expansion body is driven to rotate outwardly through the connecting plate III (135).

[0067] The plate seat IV (136) is fixed to the lower end of the piston tube (102) of the hollow oil cylinder (101), and the top rod III (137) is connected to the upper end of the plate seat IV (136), and the bottom end of the top rod III (137) passes through a hole in the bottom surface of an ear seat (6) at the bottom end of the core tube (3) and abuts against the upper end surface of the corresponding side of the drill tip assembly (8) in the closed concrete passage opening state, and in the process of rotating out of the expanding body, the top rod III (137) moves downward to push the drill tip assembly (8) to rotate around the shaft I (7) to open the concrete passage opening.

[0068] As preferred, in the embodiment, the expanding teeth III (138) at the lower end of the lower body III (132) of the expanding body in the retracted state are outside the cylindrical surface formed by the spiral blade (2). Of course, the expanding teeth III (138) at the lower end of the lower body III (132) of the expanding body in the retracted state can also be on or in the cylindrical surface formed by the spiral blade (2).

[0069] The working principle of the utility model is:

[0070] The hollow oil cylinder has two reliable positions, i.e. the positions of the piston of the oil cylinder at both ends of the inner cavity of the oil cylinder. The piston tube of the hollow oil cylinder moves downward to drive the expanding body to rotate out through a joint plate or a rack and pinion meshing pair, so that the expanding cutting construction can be performed; for the expanding device provided with a top rod, in the process of rotating out of the expanding body, the bottom end of the top rod pushes the drill tip assembly to rotate in the direction of opening the concrete passage opening of the drill bit, so that the smoothness of the concrete pouring is realized.

[0071] The expanding drill bit with the same outer diameter can realize different expanding values by replacing different lower bodies of the expanding body. When the maximum outer edge of the cutting part of the lower body is located in the outer diameter cylindrical surface of the spiral blade of the drill bit, the expanding value of the pile section formed by the expanded body after being rotated out is small, when the maximum outer edge of the cutting part of the lower body is located outside the outer diameter cylindrical surface of the spiral blade of the drill bit, the expanding value of the pile section formed by the expanded body after being rotated out is large, and when the maximum outer edge of the cutting part of the lower body is located in the outer diameter cylindrical surface of the spiral blade of the drill bit, the expanding value of the pile section formed by the expanded body after being rotated out is between the two values. For the drill bit with the maximum outer edge of the cutting part of the lower body located outside the outer diameter cylindrical surface of the spiral blade of the drill bit, a spiral groove is formed on the cylindrical pile hole wall by the protruding cutting part of the lower body during the pile hole construction, and the soil on the top fills most of the spiral groove during the lowering process, and the remaining groove is filled with concrete during the lifting and pouring process, and after solidification, discontinuous concrete protrusions are formed on the outer surface of the cylindrical concrete pile body, which is beneficial to the improvement of the lateral resistance of the pile body.

[0072] The hole-forming and pile-forming construction process: in the case that the diameter-expanding body of the drill bit is in the retracted state and the drill tip assembly is in the closed state, after drilling to the designed pile hole depth, the concrete is first pressed into the inner hole cavity at the bottom of the drill bit, then the rotating drill bit is slowly lifted while the diameter-expanding body is driven to rotate out, the concrete is poured into the bottom of the pile hole and the diameter-expanding cavity formed by the diameter-expanding body, the diameter-expanded pile section is formed by lifting and pressing the expanded diameter to the designed elevation, the diameter-expanded body is retracted, then the drill bit is lifted and pressed to form the column pile section or the screw thread pile section. The diameter-expanded pile section is divided into two cases: for the fast rotation and slow lifting of the drill bit, the diameter-expanded column pile section is formed, and for the rotation and lifting with a certain pitch relationship, the diameter-expanded screw thread pile section is formed. For the construction of the diameter-expanded pile section requiring the re-compacted concrete, the diameter-expanding body can be retracted or rotated out for drilling to form a larger diameter-expanded pile section.

Claims

1. A diameter expansion device for a variable-diameter cast-in-place pile construction drill bit, comprising a joint (1), a helical blade (2), a core pipe (3), a concrete pouring pipe (5), an ear seat (6), a shaft I (7), a drill tip assembly (8), and a cutting tooth (9); characterized in that, The device is provided with a diameter expanding device, which comprises a hollow oil cylinder (101), a diameter expanding body, a shaft II (103) and a guiding connecting device; the cylinder body of the hollow oil cylinder (101) is fixed on the inner wall of the core pipe (3), and the concrete pouring pipe (5) penetrates the inner hole cavity of the piston pipe (102) of the hollow oil cylinder (101); the diameter expanding body comprises an upper body and a lower body, the upper body and the lower body are fastened by bolts, the outer side of the upper end of the upper body is hinged to the seat body (104) arranged on the wall of the core pipe (3) through the shaft II (103), the inner side of the upper end of the upper body is connected to the lower end of the piston pipe (102) of the hollow oil cylinder (101) through the guiding connecting device, and the core pipe (3) and the spiral blade (2) at the position corresponding to the diameter expanding body are each provided with an opening for the diameter expanding body to rotate through; the up-and-down movement of the piston pipe (102) drives the diameter expanding body to rotate around the shaft II (103).

2. The reaming device for a variable-diameter cast-in-place pile construction drill bit according to claim 1, characterized by, The diameter expanding body comprises an L-shaped upper body I (111) and a lower body I (112), the upper end arm of the L-shaped upper body I (111) is in the form of a circular ring, the inner core (113) is hollow and is in clearance fit with the concrete pouring pipe (5), the outer edge of the upper end arm of the L-shaped upper body I (111) is provided with a U-shaped notch (114), the outer side of the upper end of the L-shaped upper body I (111) is hinged to the seat body (104) arranged on the wall of the core pipe (3) through the shaft II (103), and the lower end arm of the L-shaped upper body I (111) is fastened to the lower body I (112) through bolts; the guiding connecting device comprises a plate seat I (115) and a connecting plate I (116); one end of the plate seat I (115) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), the other end is hinged to one end of the connecting plate I (116) through a pin, and the other end of the connecting plate I (116) is hinged to the U-shaped notch (114) of the L-shaped upper body I (111) through a pin; the core pipe (3) and the spiral blade (2) are provided with notches at positions corresponding to the connecting plate I (116) for the up-and-down movement of the connecting plate I (116), and the baffle (4) closes the notches on the core pipe (3) corresponding to the connecting plate I (116).

3. The reaming device for a variable-diameter cast-in-place pile construction drill bit according to claim 2, characterized by, A top rod I (117) is arranged, the upper end of the top rod I (117) is hinged to the lug plate (118) arranged at the lower end of the connecting plate I (116) through a pin, the bottom end of the top rod I (117) penetrates a hole arranged on the bottom surface of the core pipe (3) and an ear seat (6), and abuts against the upper end surface of the corresponding side of the drill tip assembly (8) in the state of closing the concrete channel, in the process of rotating out of the diameter expanding body, the top rod I (117) moves downward to drive the drill tip assembly (8) to rotate around the shaft I (7) and open the concrete channel.

4. The reaming device for a variable-diameter cast-in-place pile construction drill bit according to claim 2, characterized by, When the diameter expanding body is in the retracted state, the maximum outer edge of the diameter expanding tooth I (119) at the lower end of the lower body I (112) is in, on or out of the cylindrical surface formed by the spiral blade (2).

5. The reaming device for a variable-diameter cast-in-place pile construction drill bit according to claim 1, characterized by, The diameter expander comprises an upper body II (121) and a lower body II (122), the upper end of the upper body II (121) is cylindrical, the upper end of the upper body II (121) is hinged to the seat body (104) arranged on the wall of the core pipe (3) through the shaft II (103), the inner side of the upper end of the upper body II (121) is provided with a tooth (123), and the lower end of the upper body II (121) is fastened to the lower body II (122) through a bolt; the guiding connecting device comprises a rack (124), the rack (124) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), and the tooth (123) is engaged with the rack (124).

6. The reaming device for a jacked pile construction drill bit according to claim 5, wherein A plate seat II (125) and a top rod II (126) are arranged, the upper end of the plate seat II (125) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), the upper end of the top rod II (126) is connected to the plate seat II (125), the bottom end of the top rod II (126) penetrates through the hole arranged in the bottom end of the core pipe (3) and the bottom surface of an ear seat (6) and abuts against the upper end surface of the corresponding side of the drill tip assembly (8) in the state of closing the concrete passage, in the process of rotating out of the diameter expander, the top rod II (126) moves downward to drive the drill tip assembly (8) to rotate around the shaft I (7) and open the concrete passage.

7. The reaming device for a jacked pile construction drill bit according to claim 5, wherein In the retracted state of the diameter expander, the maximum outer edge of the diameter expanding tooth II (127) at the lower end of the lower body II (122) is in, on or out of the cylindrical surface formed by the spiral blade (2).

8. The reaming device for a jacked pile construction drill bit of claim 1, wherein The diameter expander comprises an upper body III (131) and a lower body III (132), the upper end of the upper body III (131) is cylindrical, the upper end of the upper body III (131) is hinged to the seat body (104) arranged on the wall of the core pipe (3) through the shaft II (103), the middle part of the upper body III (131) is provided with a groove (133), and the lower end of the upper body III (131) is fastened to the lower body III (132) through a bolt; the guiding connecting device comprises a plate seat III (134) and a connecting plate III (135), one end of the plate seat III (134) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), the other end is hinged to one end of the connecting plate III (135) through a pin, the other end of the connecting plate III (135) is inserted into the groove (133) and hinged to the upper body III (131) through a pin.

9. The reaming device for a jacked pile construction drill bit according to claim 8, characterized in that, A plate seat IV (136) and a top rod III (137) are arranged, the upper end of the plate seat IV (136) is fixed to the lower end of the piston pipe (102) of the hollow oil cylinder (101), the upper end of the top rod III (137) is connected to the plate seat IV (136), the bottom end of the top rod III (137) penetrates through the hole arranged in the bottom end of the core pipe (3) and the bottom surface of an ear seat (6) and abuts against the upper end surface of the corresponding side of the drill tip assembly (8) in the state of closing the concrete passage, in the process of rotating out of the diameter expander, the top rod III (137) moves downward to drive the drill tip assembly (8) to rotate around the shaft I (7) and open the concrete passage.

10. The reaming device for a jacked pile construction drill bit according to claim 8, characterized by, In the retracted state of the diameter expander, the maximum outer edge of the diameter expanding tooth III (138) at the lower end of the lower body III (132) is in, on or out of the cylindrical surface formed by the spiral blade (2).

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