Anti-reversion mechanism for drill bit mandrel

Abstract

The utility model discloses a drill bit mandrel anti-reversion mechanism which comprises a square hole drill bit body, a center rotating shaft is assembled on the upper portion of the square hole drill bit body in a rotating mode, an assembling space is formed in the square hole drill bit body, and a balancing weight is installed in the assembling space in an up-down sliding mode. A transmission assembly is arranged between the balancing weight and the center rotating shaft, the center rotating shaft rotates in a one-way mode, and the balancing weight can be driven by the transmission assembly to continuously move up and down in the square hole drill bit body so that rammer drilling of the drill bit can be achieved. The central rotating shaft is fixedly sleeved with a ratchet wheel, pawls distributed in the circumferential direction of the ratchet wheel are installed on the square hole drill bit body, and all the pawls are attached to the circumferential side portion of the ratchet wheel through elastic elements; and under the interaction of the pawl and the ratchet wheel, the central rotating shaft can only rotate in one direction relative to the square hole drill bit main body. The drill bit has the advantages that reverse rotation of the central rotating shaft can be limited, and the service life of the drill bit can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of drilling, in particular to a drill core shaft anti-reversal mechanism. Background Art

[0002] At present, concrete cast-in-place piles can be classified into round piles and square piles according to the different cross-sectional shapes of the pile body. Although round piles are the most common, square piles have a larger lateral surface area than round piles when the cross-sectional area is the same, so that the pile body can obtain greater lateral friction resistance underground, thereby effectively improving the bearing capacity of a single pile, and square piles have better shear resistance and seismic performance.

[0003] However, in the construction of concrete cast-in-place pile foundation projects, pile holes are usually prepared by rotary drilling, so it is easiest to prepare circular pile holes. But if square piles are used, it is usually necessary to first dig a circular hole, and then manually trim the circular hole so that the shape of the square hole meets the standard. This method is time-consuming and labor-intensive, and wastes a lot of workers' physical strength.

[0004] In order to solve the problems of low efficiency and high labor intensity of traditional excavation, the designer proposes a square hole drill that can directly mine square holes on the ground. The implementation method is as follows: the drill body is constructed into a square hollow structure, and a counterweight block that can move up and down is configured inside it. Then, the counterweight block is driven by the driving mechanism to rise to the highest point inside the square drill, and then the driving force is interrupted. The counterweight block falls rapidly to the bottom of the square drill by its own weight, forming a ramming state, so that the square drill body continues to sink to form a square hole.

[0005] In the above development process of the square drill, the driving mechanism uses a transmission shaft to directly or indirectly control the movement of the rack and pinion mechanism to drive the counterweight upward. However, when the counterweight is at the lowest position, if the transmission shaft reverses, the counterweight will tend to move further downward, causing damage to the rack and pinion components in the driving mechanism, thus reducing the service life of the square hole drill. Utility Model Content

[0006] In view of this, the utility model provides a drill core shaft anti-reversal mechanism, which aims to solve the problem that the reversal of the transmission shaft will cause the counterweight block to have a tendency to move further downward.

[0007] To achieve the above purpose, the technical solution of the utility model is as follows:

[0008] A drill core shaft anti-reversal mechanism comprises a square hole drill body, a central rotating shaft is rotatably mounted on the upper part of the square hole drill body, an assembly space is opened inside the square hole drill body, a counterweight block is slidably mounted in the assembly space, a transmission assembly is arranged between the counterweight block and the central rotating shaft, the central rotating shaft rotates unidirectionally, and can drive the counterweight block to continuously move up and down inside the square hole drill body through the transmission assembly to realize hammer drilling of the drill bit.

[0009] A ratchet is fixedly mounted on the central rotating shaft, and pawls distributed around the ratchet are installed on the square hole drill body, and each of the pawls is attached to the circumferential side of the ratchet through an elastic element; under the interaction between the pawls and the ratchet, the central rotating shaft can only rotate unidirectionally relative to the square hole drill body.

[0010] Preferably, the circumferential side of the ratchet is provided with tooth grooves and gear teeth arranged alternately in sequence, one end of the pawl is rotatably connected to the square hole drill body, and the other end is pressed by an elastic element to contact the circumferential side of the ratchet.

[0011] Preferably, the pawl is an arc-shaped block, one end of which is rotatably mounted on the square hole drill body via a positioning shaft.

[0012] Preferably, the elastic element is a spring sheet, one end of which is fixed to the square hole drill body, and the other end is pressed against the end of the pawl away from the positioning shaft, and exerts a force to keep the pawl in close contact with the circumferential side of the ratchet.

[0013] Preferably, a fixing seat is provided on the main body of the square hole drill bit, a strip-shaped notch is provided on the fixing seat, and one end of the spring sheet is clamped in the strip-shaped notch.

[0014] Preferably, a sealing plate is provided at the lower end of the assembly space.

[0015] Preferably, an upper end cover is provided on the upper part of the square hole drill body, and the central shaft is rotatably installed at the position of the upper end cover.

[0016] Preferably, four groups of guide rods are distributed in a rectangular shape in the assembly space, and the counterweight block is slidably mounted on the four groups of lifting rods.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1. When the counterweight is at the lowest position, if the center shaft reverses, the tooth groove of the ratchet will hit the pawl, forming a ratchet engagement limit. At this time, the driving force of the center shaft acts on the drill bit as a whole, and will not be transmitted to the transmission assembly, thereby ensuring that the counterweight has no tendency to move further downward, reducing the risk of damage to the corresponding components in the lifting transmission assembly and increasing the service life of the square hole drill.

[0019] 2. Due to the anti-reversal structure, the drilling equipment drives the central shaft to rotate in the opposite direction. If the rotational driving force can break through the resistance of the formed square hole, the square hole can be reshaped into a round hole, thereby expanding the round hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of a square hole drill bit in an embodiment;

[0021] Figure 2 A schematic diagram showing the partial structure of the upper portion of a square hole drill head and its internal counterweight block;

[0022] Figure 3 A cross-sectional view showing the installation relationship between the pawl a1 and the ratchet a2 in the drill spindle anti-reverse mechanism;

[0023] Figure 4 is a schematic structural diagram of the worm 45;

[0024] Figure 5 It is a structural schematic diagram of the transmission assembly 4;

[0025] Figure 6 It is a schematic diagram of the structure of the gear 42. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with embodiments and drawings.

[0027] like Figure 1 , 2 As shown in Figure 3, a drill bit includes a square hole drill bit body 3 and a central shaft 1 rotatably assembled on the upper part of the square hole drill bit body 3, the central shaft 1 is used to connect with a power source, the square hole drill bit body 3 is a rectangular structure as a whole, an assembly space A is opened inside it, a counterweight block 5 that can slide up and down relative to the square hole drill bit body 3 is installed in the assembly space A, a transmission component 4 is arranged between the counterweight block 5 and the central shaft 1, the counterweight block 5 can realize continuous linear lifting motion through the internal transmission component 4, forming a rammer state for the square hole drill bit body 3, so that the square drill bit body continues to sink to form a square hole.

[0028] In this embodiment, the structure and working principle of the transmission assembly 4 are as follows:

[0029] like Figure 5As shown, the transmission assembly 4 includes a worm 45, two groups of worm wheels 43, two support shafts 41, four gears 42 and four racks 44. The worm 45 is rotatably installed inside the square hole drill body 3. The two groups of worm wheels 43 are symmetrically meshed on both sides of the worm 45. The two support shafts 41 are rotatably set inside the square hole drill body 3. Each support shaft 41 is equipped with a worm wheel 43 and two gears 42. The four racks 44 are distributed in a rectangular array and fixed in the counterweight block 5. The four groups of racks 44 correspond to the four groups of gears 42 one by one. Figure 6 It can be seen that the gear 42 has an arc-shaped meshing section 4a and a non-meshing area 4b. The upper part of the worm 45 is fixedly connected to the central shaft 1 through a spline, and the two can rotate synchronously. Therefore, the external power source drives the central shaft 1 to rotate, and can drive the gear 42 to rotate in sequence through the worm 45 → worm wheel 43 → support shaft 41. Within the single-turn rotation stroke of the gear 42, when the arc-shaped tooth segment 4a is meshed with the rack 44, the rotation of the gear 42 can drive the counterweight 5 to move upward. When the arc-shaped tooth segment 4a is disengaged from the rack 44, that is, when the non-meshing area 4b of the gear 42 is opposite to the rack, the counterweight 5 can fall due to its own gravity. At this point, the lifting and lowering movement of the counterweight 5 inside the drill bit is realized.

[0030] When the counterweight 5 is at the lowest point, if the worm 45 rotates in the opposite direction, the gear 42 will also reverse, and the gear 42 will drive the rack 44 to move downward, thereby driving the counterweight 5 to continue to move downward. Since the counterweight 5 is at the lowest point at this time, it will cause the counterweight 5 to have a tendency to move further downward, causing the corresponding parts in the transmission assembly 4 to be damaged, thereby reducing the service life of the square hole drill. To this end, the present embodiment provides a ratchet mechanism between the central shaft 1 and the square hole drill body 3, specifically:

[0031] Please refer to the attached Figure 2 and 3 The square hole drill body 3 has an upper end cover 31, and the central shaft 1 is rotatably mounted in the middle of the upper end cover 31. The upper end cover 31 has a cylindrical sleeve portion 311 in the center, and a plurality of groups of reinforcing ribs 312 are distributed between the sleeve portion 311 and the upper end cover 31 to strengthen the strength of the sleeve portion 311. A ratchet a2 is fixedly sleeved on the central shaft 1, and ratchet pawls a1 distributed around the ratchet a2 are installed on the square hole drill body 3, and each of the ratchet pawls a1 is attached to the circumferential side of the ratchet a2 through an elastic element. In this embodiment, the ratchet pawl a1 is an arc-shaped block, one end of which is rotatably mounted on the bottom end of the sleeve portion 311 of the square hole drill body 3 through a positioning shaft b. The elastic element a3 is a spring sheet, one end of which is fixed to the bottom end of the sleeve portion 311 of the square hole drill body 3, and the other end is pressed on the end of the pawl a1 away from the positioning axis b, and exerts a force to keep the pawl a1 in contact with the circumferential side of the ratchet a2.

[0032] Based on the above design, the drill bit mandrel anti-reversal principle is as follows:

[0033] When the central shaft 1 rotates forward, the pawl a1 will slide over the outer wall of the ratchet a2, and no power will be transmitted between the pawl a1 and the ratchet a2. The power of the central shaft 1 can be transmitted to the worm 45 of the transmission assembly in turn, driving the counterweight 5 to perform continuous lifting and lowering movements and exerting gravity potential energy on the square hole drill body 3, so that the square hole drill body 3 continues to sink in the soil to form a square hole. When the counterweight 5 is at the lowest position, if the central shaft 1 is reversed, the tooth groove of the ratchet will hit the pawl, forming a ratchet meshing transmission. At this time, the driving force of the central shaft 1 acts on the drill bit as a whole, and will not be transmitted to the transmission assembly 4, thereby ensuring that the counterweight 5 does not have a tendency to move further downward, reducing the risk of damage to the corresponding components in the lifting transmission assembly 4, and increasing the service life of the square hole drill.

[0034] For example Figure 3 As shown, the ratchet a2 is provided with tooth grooves a21 and gear teeth a22 arranged alternately in sequence on the circumferential side, and the inner wall of the pawl a1 is an arc surface, which ensures that when the ratchet a2 rotates forward, the pawl a1 can smoothly pass through the outer wall of the gear teeth a22. For easy assembly, a fixing seat 3a is provided at the bottom end of the sleeve portion 311 of the square hole drill body 3, and a strip-shaped notch is provided on the fixing seat 3a, and one end of the spring sheet is clamped in the strip-shaped notch.

[0035] like Figure 1 As shown, a sealing plate 32 is provided at the lower end of the assembly space A. The sealing plate 32 is integrally formed with the square hole drill body 3 to prevent mud and sand from entering the assembly space A and affecting the normal operation of the internal transmission parts. Figure 2 There are four sets of lifting rods 6 arranged in a rectangular shape in the assembly space A. One end of the four sets of lifting rods 6 is fixedly mounted on the bottom of the upper end cover 31, and the other end is fixedly mounted on the top of the sealing plate 32. The counterweight 5 slides up and down on the four sets of lifting rods 6. Figure 3 and Figure 4 A transmission spline hole 11 is formed at the lower end of the central rotating shaft 1, and a transmission spline tooth 21 adapted to the transmission spline hole 11 is formed at the upper end of the worm 45. The central rotating shaft 1 and the worm 45 transmit power through the spline.

[0036] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make a variety of similar expressions without violating the purpose and claims of the present invention, and such changes fall within the scope of protection of the present invention.

Claims

1. A drill bit spindle anti-reversal mechanism, characterized in that: The invention comprises a square hole drill body (3), wherein a central rotating shaft (1) is rotatably mounted on the upper part of the square hole drill body (3), an assembly space (A) is provided inside the square hole drill body (3), a counterweight block (5) is slidably mounted in the assembly space (A), a transmission assembly (4) is provided between the counterweight block (5) and the central rotating shaft (1), the central rotating shaft (1) rotates in one direction, and can drive the counterweight block (5) to continuously move up and down inside the square hole drill body (3) through the transmission assembly (4), so as to realize hammer drilling of the drill bit; A ratchet (a2) is fixedly sleeved on the central rotating shaft (1), and ratchet pawls (a1) distributed around the ratchet (a2) are installed on the square hole drill bit body (3), and each of the ratchet pawls (a1) is attached to the circumferential side of the ratchet (a2) through an elastic element; under the interaction between the ratchet pawls (a1) and the ratchet (a2), the central rotating shaft (1) can only rotate in one direction relative to the square hole drill bit body (3).

2. The drill bit spindle anti-reversal mechanism according to claim 1, characterized in that: The circumferential side of the ratchet (a2) is provided with tooth grooves (a21) and gear teeth (a22) arranged alternately in sequence, one end of the ratchet pawl (a1) is rotatably connected to the square hole drill body (3), and the other end is pressed by the elastic element (a3) ​​to contact the circumferential side of the ratchet (a2).

3. The drill bit spindle anti-reversal mechanism according to claim 1, characterized in that: The ratchet (a1) is an arc-shaped block, one end of which is rotatably mounted on the square hole drill body (3) via a positioning shaft (b).

4. The drill core shaft anti-reversal mechanism according to claim 3, characterized in that: The elastic element (a3) ​​is a spring sheet, one end of which is fixed on the square hole drill body (3), and the other end is pressed on the end of the pawl (a1) away from the positioning shaft (b), and exerts a force to keep the pawl (a1) and the circumferential side of the ratchet (a2) in contact.

5. The drill bit spindle anti-reversal mechanism according to claim 4, characterized in that: The square hole drill body (3) is provided with a fixing seat (3a), the fixing seat (3a) is provided with a strip-shaped notch, and one end of the spring sheet is clamped in the strip-shaped notch.

6. The drill spindle anti-reversal mechanism according to claim 1, characterized in that: A sealing plate (32) is provided at the lower end of the assembly space (A).

7. The drill spindle anti-reversal mechanism according to claim 1, characterized in that: An upper end cover (31) is provided on the upper part of the square hole drill body (3), and the central rotating shaft (1) is rotatably mounted on the position of the upper end cover (31).

8. The drill spindle anti-reversal mechanism according to claim 1, characterized in that: Four groups of guide rods (6) are distributed in a rectangular shape in the assembly space (A), and the counterweight block (5) is slidably mounted on the four groups of guide rods (6) up and down.

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