阅读说明：本技术 一种带自楔紧装置的打桩锤组合锤头 (Combined hammer head of piling hammer with self-wedging device ) 是由 陈太清 刘鹏鹏 杨顺钦 王爱军 王兴云 张为军 于 2021-09-29 设计创作，主要内容包括：本发明涉及桩工机械技术领域,具体涉及一种带自楔紧装置的打桩锤组合锤头,包括主锤头、以及设置在主锤头上的副锤头组件、预紧装置和阻挡装置,预紧装置和阻挡装置依次设于副锤头组件的上方；副锤头组件包括由上至下依次叠加设置的第一副锤头、第二副锤头和第三副锤头,第一副锤头和第二副锤头之间、第二副锤头和第三副锤头之间、以及第三副锤头和主锤头之间均留有间隙；本发明使得组合锤头向下加速运动时实现了延长锤击时间、降低应力波的峰值的效果,在提高冲击能的传递效率和打桩贯入度的同时,降低打桩锤及桩所承受的冲击力,有利于提高打桩锤的寿命,保护桩体不被打坏；并有效提高了组合锤头连接机构的可靠性,降低了打桩锤锤头的制造成本。(The invention relates to the technical field of piling machinery, in particular to a piling hammer combined hammer head with a self-wedging device, which comprises a main hammer head, an auxiliary hammer head component, a pre-tightening device and a blocking device, wherein the auxiliary hammer head component, the pre-tightening device and the blocking device are arranged on the main hammer head; the auxiliary hammer head component comprises a first auxiliary hammer head, a second auxiliary hammer head and a third auxiliary hammer head which are sequentially overlapped from top to bottom, and gaps are reserved between the first auxiliary hammer head and the second auxiliary hammer head, between the second auxiliary hammer head and the third auxiliary hammer head and between the third auxiliary hammer head and the main hammer head; the invention realizes the effects of prolonging the hammering time and reducing the peak value of stress wave when the combined hammer head moves downwards in an accelerated way, improves the transmission efficiency of impact energy and the pile driving penetration degree, reduces the impact force born by the pile driving hammer and the pile, is beneficial to prolonging the service life of the pile driving hammer and protects the pile body from being damaged; and the reliability of the combined hammer head connecting mechanism is effectively improved, and the manufacturing cost of the hammer head of the pile hammer is reduced.)

1. The utility model provides a pile hammer combination tup from wedging device in area which characterized in that: the device comprises a main hammer head (1), and an auxiliary hammer head component, a pre-tightening device and a blocking device which are arranged on the main hammer head (1), wherein the pre-tightening device and the blocking device are sequentially arranged above the auxiliary hammer head component;

the auxiliary hammer head component comprises a first auxiliary hammer head (11), a second auxiliary hammer head (13) and a third auxiliary hammer head (15) which are sequentially overlapped from top to bottom, and gaps are reserved between the first auxiliary hammer head (11) and the second auxiliary hammer head (13), between the second auxiliary hammer head (13) and the third auxiliary hammer head (15) and between the third auxiliary hammer head (15) and the main hammer head (1); a first elastic washer (12) is arranged at a gap between the first auxiliary hammer head (11) and the second auxiliary hammer head (13), a second elastic washer (14) is arranged at a gap between the second auxiliary hammer head (13) and the third auxiliary hammer head (15), and a third elastic washer (16) is arranged at a gap between the third auxiliary hammer head (15) and the main hammer head (1);

the center position of the first auxiliary hammer head (11) is provided with a conical hole, an opening taper sleeve (10) is installed in the conical hole, a gap is formed between the small end face of the bottom of the opening taper sleeve (10) and the small end face in the conical hole after the opening taper sleeve (10) is installed in the conical hole, and the large end face of the top of the opening taper sleeve (10) protrudes out of the upper end face of the first auxiliary hammer head (11) and forms a gap with the pre-tightening device.

2. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: the pre-tightening device comprises a disc spring seat (9) sleeved on the main hammer head (1), a plurality of disc spring mounting holes are formed in the disc spring seat (9), the disc spring mounting holes are distributed in a circumferential uniform interval mode, and each disc spring assembly (8) is installed in each disc spring mounting hole.

3. The piling hammer combined hammer head with the self-wedging device as claimed in claim 2, characterized in that: the disc spring assembly is characterized in that a disc spring pressing block (7) is arranged at the top of the disc spring assembly (8), a disc spring pressing cover (6) is arranged on the disc spring pressing block (7), pretightening force is applied to the disc spring assembly (8) by the disc spring pressing cover (6) through the disc spring pressing block (7) and the screw rod assembly (5), and a gap is formed between the lower end face of the disc spring pressing cover (6) and the upper end face of the disc spring seat (9).

4. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: the stop device comprises a limiting ring (3) sleeved on the main hammer head (1) and a hot sleeve ring (4) sleeved on the outer circle of the limiting ring (3), wherein a step is arranged between the outer circle of the limiting ring (3) and the inner hole of the hot sleeve ring (4), and the outer circle of the limiting ring (3) and the inner hole of the hot sleeve ring (4) are in interference connection.

5. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: the top of the main hammer head (1) is provided with a clamping key groove, a semicircular clamping key (2) is installed in the clamping key groove, and a gap is reserved between the semicircular clamping key (2) and an inner hole of the hot ferrule (4).

6. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: the gap between the first auxiliary hammer head (11) and the second auxiliary hammer head (13) is delta 4, the gap between the second auxiliary hammer head (13) and the third auxiliary hammer head (15) is delta 5, the gap between the third auxiliary hammer head (15) and the main hammer head (1) is delta 6, the delta 4, the delta 5 and the delta 6 are respectively elastic deformation amounts of the first elastic washer (12), the second elastic washer (14) and the third elastic washer (16), the delta 4, the delta 5 and the delta 6 are elastic deformation amounts, and the impact energy is determined by calculation according to different impact energy positions of the first auxiliary hammer head (11), the second auxiliary hammer head (13) and the third auxiliary hammer head (15): delta 4 < delta 5 < delta 6.

7. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: gaps are reserved on the left side and the right side of the first elastic gasket (12), the second elastic gasket (14) and the third elastic gasket (16).

8. The piling hammer combined hammer head with the self-wedging device as claimed in claim 1, characterized in that: the excircle of the opening taper sleeve (10) is conical, the inner hole of the opening taper sleeve (10) is a cylindrical hole, and the opening taper sleeve (10) is cut along a generatrix to form an opening (17) with a gap delta 9.

Technical Field

The invention relates to the technical field of piling machinery, in particular to a piling hammer combined hammer head with a self-wedging device.

Background

The hydraulic pile hammer is a new type of engineering pile driving machinery which is used for overcoming the problems of large noise and pollution of the diesel hammer, and drives the hammer head to do up-and-down reciprocating motion through a hydraulic driving device, so as to strike the lower anvil block, and then the striking kinetic energy of the hammer head is transmitted to the pile body by the lower anvil block, so as to drive the pile body to downwards penetrate into soil, thus becoming the key equipment for engineering construction such as marine oil and gas field exploitation, offshore wind power foundation construction, bridge pile foundation construction and the like.

Among the prior art, the pile hammer tup generally adopts whole tup, and the shortcoming that this kind of tup exists is: a is manufactured integrally, particularly a large-energy pile hammer, the hammer head mass reaches (or is more than) 175 tons, and manufacturers with the steel ingot smelting, forging, hoisting, processing and heat treatment capacities are few, so that the manufacturing cost is high; and B, because the striking time of the hammer head striking the lower anvil block is short, the impact stress between the hammer head and the lower anvil block and between the lower anvil block and the pile is high, and particularly when the penetration of each hammer is less than 2 millimeters (the phenomenon is called as 'hammer rejection'), the peak value of the impact stress is larger, and the phenomena of hammer head upsetting and pile head cracking are easier to occur.

Chinese patent ZL 2013203105754 discloses a combined hammer head of a pile hammer, which is stacked on a main hammer head through an auxiliary hammer head, wherein a first vibration absorption elastic element is arranged between the main hammer head and the auxiliary hammer head, and the main hammer head and the auxiliary hammer head are connected into a whole through an elastic connection assembly. The technology can effectively control the maximum striking force, reduce striking rebound, prolong the striking time, improve the penetration degree of the piling and effectively protect the precast concrete pile head on the basis of ensuring that the striking energy is not changed. However, the technology has the defect that the connection mechanism of the auxiliary hammer head and the main hammer head is damaged and fails due to the fact that the impact resilience of the auxiliary hammer head is large under the condition of high-energy pile driving, and particularly under the condition that the pile body is rejected during high-energy pile driving, the connection mechanism of the auxiliary hammer head and the main hammer head is more easily damaged and fails, and the reliability of the hydraulic pile driving hammer is influenced.

Chinese patent document ZL2014106736606 discloses a combined hammer head for a hydraulic pile hammer, in which the interior of the hammer body is designed as a hollow structure, and the metal particle filler is filled in the hollow cavity to form the combined hammer head, and lags behind the hammer body when the hammer head strikes. The technology effectively improves the stress waveform when the hammer head impacts, reduces the peak value of the stress wave to the minimum required value, prolongs the transmission time of the stress wave in the peak value state, improves the transmission efficiency of impact energy and the pile driving penetration degree, reduces the impact force born by the pile driving hammer and the pile, is beneficial to prolonging the service life of the pile driving hammer, and protects the pile body from being damaged. This technique also has vice tup and main tup coupling mechanism to damage the not enough of inefficacy easily, still has the proportion of metal particle filler little simultaneously, compares with the tup of the same mass, and the bigger shortcoming of volume to still there is because metal particle constantly strikes cavity inner wall, can cause cavity wall thickness attenuate phenomenon after long-time work, influences the defect of tup life-span.

Disclosure of Invention

In order to solve the problems, the invention provides the pile hammer combined hammer head with the self-wedging device, the auxiliary hammer head component, the pre-tightening device and the blocking device are arranged on the main hammer head, so that the effects of prolonging the hammering time and reducing the peak value of stress waves of the combined hammer head are realized, the impact force borne by the pile hammer and the pile is reduced while the transmission efficiency of impact energy and the pile penetration are improved, the service life of the pile hammer is prolonged, and the pile body is protected from being damaged.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a pile hammer combined hammer head with a self-wedging device comprises a main hammer head, an auxiliary hammer head component, a pre-tightening device and a blocking device, wherein the auxiliary hammer head component, the pre-tightening device and the blocking device are arranged on the main hammer head, and the pre-tightening device and the blocking device are sequentially arranged above the auxiliary hammer head component;

the auxiliary hammer head component comprises a first auxiliary hammer head, a second auxiliary hammer head and a third auxiliary hammer head which are sequentially overlapped from top to bottom, and gaps are reserved between the first auxiliary hammer head and the second auxiliary hammer head, between the second auxiliary hammer head and the third auxiliary hammer head and between the third auxiliary hammer head and the main hammer head; a first elastic washer is arranged at a gap between the first auxiliary hammer head and the second auxiliary hammer head, a second elastic washer is arranged at a gap between the second auxiliary hammer head and the third auxiliary hammer head, and a third elastic washer is arranged at a gap between the third auxiliary hammer head and the main hammer head;

the center of the first auxiliary hammer is provided with a conical hole, an opening taper sleeve is arranged in the conical hole, a gap is formed between the small end face of the bottom of the opening taper sleeve and the small end face in the conical hole after the opening taper sleeve is arranged in the conical hole, and the large end face of the top of the opening taper sleeve protrudes out of the upper end face of the first auxiliary hammer and forms a gap with the pre-tightening device.

Preferably, the pre-tightening device comprises a disc spring seat sleeved on the main hammer head, a plurality of disc spring mounting holes are formed in the disc spring seat and are circumferentially distributed at even intervals, and disc spring assemblies are mounted in the disc spring mounting holes.

Preferably, a disc spring pressing block is arranged at the top of the disc spring assembly, a disc spring pressing cover is arranged on the disc spring pressing block, pretightening force is applied to the disc spring assembly by the disc spring pressing cover through the disc spring pressing block and the screw assembly, and a gap is formed between the lower end face of the disc spring pressing cover and the upper end face of the disc spring seat.

By adopting the technical scheme, the disc spring pressing block is arranged in the disc spring mounting hole of the disc spring seat, so that the effects of pressing and guiding the disc spring are achieved.

Preferably, the blocking device comprises a limiting ring sleeved on the main hammer head and a hot sleeve ring sleeved on the outer circle of the limiting ring, a step is arranged between the outer circle of the limiting ring and the inner hole of the hot sleeve ring, and the outer circle of the limiting ring and the inner hole of the hot sleeve ring are in interference connection.

Preferably, a key clamping groove is formed in the top of the main hammer head, a semicircular clamping key is installed in the key clamping groove, and a gap is reserved between the semicircular clamping key and an inner hole of the hot sleeve ring.

Preferably, the gap between the first and second sub-hammers is δ 4, the gap between the second and third sub-hammers is δ 5, the gap between the third sub-hammer and the main hammer is δ 6, δ 4, δ 5 and δ 6 are elastic deformation amounts of the first, second and third elastic washers, respectively, δ 4, δ 5 and δ 6 are elastic deformation amounts, and the magnitude of the elastic deformation amounts is determined by calculation according to the impact energy difference at the positions of the first, second and third sub-hammers: delta 4 < delta 5 < delta 6.

Preferably, gaps are reserved on the left side and the right side of the first elastic gasket, the second elastic gasket and the third elastic gasket, and the gaps are used for accommodating the deformation volumes of the elastic gaskets towards the left side and the right side.

Preferably, the excircle of the opening taper sleeve is conical, the inner hole of the opening taper sleeve is a cylindrical hole, and the opening taper sleeve cuts an opening with a gap delta 9 along a generatrix.

The combined hammer head of the invention moves downwards in an accelerated way: the main hammer head is driven by the oil cylinder to do acceleration motion downwards, the main hammer head transmits the driving force downwards of the oil cylinder to the first auxiliary hammer head, the second auxiliary hammer head and the third auxiliary hammer head in sequence under the combined action of the blocking device, the pre-tightening device and the opening taper sleeve, and the synchronous downward acceleration motion of the auxiliary hammer head and the main hammer head is realized.

The invention has the beneficial effects that:

according to the invention, the auxiliary hammer head assembly, the pre-tightening device and the blocking device are arranged on the main hammer head, so that the effects of prolonging the hammering time and reducing the peak value of stress wave are realized when the combined hammer head moves downwards in an accelerated manner, the impact force born by the pile hammer and the pile is reduced while the transfer efficiency and the pile penetration of impact energy are improved, the service life of the pile hammer is prolonged, and the pile body is protected from being damaged; and the reliability of the combined hammer head connecting mechanism is effectively improved, and the manufacturing cost of the hammer head of the pile hammer is reduced.

Drawings

Fig. 1 is a sectional view of a combined hammer head of a pile hammer of the present invention;

fig. 2 is a top view of the combined hammer head of the pile hammer of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

fig. 4 is a sectional view taken along line B-B of fig. 1.

In the figure: 1. the hydraulic support comprises a main hammer head, 2, a semicircular clamping key, 3, a limiting ring, 4, a thermal ferrule, 5, a screw rod assembly, 6, a disc spring gland, 7, a disc spring pressing block, 8, a disc spring assembly, 9, a disc spring seat, 10, an opening taper sleeve, 11, a first auxiliary hammer head, 12, a first elastic washer, 13, a second auxiliary hammer head, 14, a second elastic washer, 15, a third auxiliary hammer head, 16, a third elastic washer, 17 and an opening.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, and thus the scope of the present invention is more clearly defined. The embodiments described herein are only a few embodiments of the present invention, rather than all embodiments, and all other embodiments that can be derived by one of ordinary skill in the art without inventive faculty based on the embodiments described herein are intended to fall within the scope of the present invention.

Referring to fig. 1-4, a pile hammer combined hammer head with a self-wedging device comprises a main hammer head 1, and an auxiliary hammer head component, a pre-tightening device and a blocking device which are arranged on the main hammer head 1, wherein the pre-tightening device and the blocking device are sequentially arranged above the auxiliary hammer head component;

the auxiliary hammer head component comprises a first auxiliary hammer head 11, a second auxiliary hammer head 13 and a third auxiliary hammer head 15 which are sequentially overlapped from top to bottom, and gaps are reserved between the first auxiliary hammer head 11 and the second auxiliary hammer head 13, between the second auxiliary hammer head 13 and the third auxiliary hammer head 15 and between the third auxiliary hammer head 15 and the main hammer head 1; a first elastic washer 12 is arranged at the gap between the first auxiliary hammer head 11 and the second auxiliary hammer head 13, a second elastic washer 14 is arranged at the gap between the second auxiliary hammer head 13 and the third auxiliary hammer head 15, and a third elastic washer 16 is arranged at the gap between the third auxiliary hammer head 15 and the main hammer head 1;

a conical hole is formed in the center of the first auxiliary hammer head 11, an opening taper sleeve 10 is installed in the conical hole, a gap is formed between the small end face of the bottom of the opening taper sleeve 10 and the small end face in the conical hole after the opening taper sleeve 10 is installed in the conical hole, and a large end face of the top of the opening taper sleeve 10 protrudes out of the upper end face of the first auxiliary hammer head 11 and a gap is formed between the large end face and the pre-tightening device.

Specifically, the first sub-hammer head 11, the second sub-hammer head 13, and the third sub-hammer head 15 are coaxially assembled on the main hammer head 1, a gap between the first sub-hammer head 11 and the second sub-hammer head 13 is δ 4, a gap between the second sub-hammer head 13 and the third sub-hammer head 15 is δ 5, a gap between the third sub-hammer head 15 and the main hammer head 1 is δ 6, δ 4, δ 5, and δ 6 are elastic deformation amounts of the first elastic washer 12, the second elastic washer 14, and the third elastic washer 16, respectively, δ 4, δ 5, and δ 6 are elastic deformation amounts, and are determined by calculation according to differences in impact energy at positions where the first sub-hammer head 11, the second sub-hammer head 13, and the third sub-hammer head 15 are located: delta 4 < delta 5 < delta 6.

Gaps are reserved on the left side and the right side of the first elastic gasket 12, the second elastic gasket 14 and the third elastic gasket 16, and the gaps are used for accommodating the deformation volumes of the elastic gaskets towards the left side and the right side.

Specifically, the excircle of the opening taper sleeve 10 is conical, the inner hole of the opening taper sleeve 10 is a cylindrical hole, the taper lambda of the excircle cone meets the self-locking condition, and the opening taper sleeve 10 cuts an opening 17 with a gap delta 9 along a bus. The opening taper sleeve 10 is arranged in a taper hole which is formed in the middle of the first auxiliary hammer head 11 and has the same taper with the opening taper sleeve, after the opening taper sleeve 10 is arranged in the first auxiliary hammer head 11, a delta 3 gap is formed between the end face of the small end of the opening taper sleeve and the end face of the small end in the taper hole, and the end face of the large end of the opening taper sleeve protrudes out of the upper end face of the first auxiliary hammer head 11 to form a delta 2 distance.

Specifically, preloading device is including cup jointing the dish spring seat 9 on main tup 1, a plurality of dish spring mounting hole has been seted up on the dish spring seat 9, and a plurality of dish spring mounting hole is the even interval distribution of circumference form, and the coaxial setting in a plurality of dish spring mounting hole and the mesopore of dish spring seat 9, every all install dish spring subassembly 8 in the dish spring mounting hole. The quantity of the disc spring mounting holes is determined by calculation according to the rebound force of the auxiliary hammer head; and the compression stroke and the elastic force of the disc spring assembly 8 are determined by calculation. The total elastic force F of the disc spring assembly is set, wherein the requirement F is larger than the driving force for driving the first auxiliary hammer head 11, the second auxiliary hammer head 13 and the third auxiliary hammer head 15 to do downward acceleration movement, and the work obtained by the total elastic force F of the disc spring assembly 8 and the distance delta 1 between the lower end surface of the disc spring gland and the upper end surface of the disc spring seat is larger than the rebound impact work of the first auxiliary hammer head 11, the second auxiliary hammer head 13 and the third auxiliary hammer head 15.

Specifically, dish spring compact heap 7 is equipped with at dish spring subassembly 8 top, set up dish spring gland 6 on the dish spring compact heap 7, dish spring gland 6 exerts the pretightning force for dish spring subassembly 8 through dish spring compact heap 7 and screw rod subassembly 5, the lower terminal surface of dish spring gland 6 and the up end of dish spring seat 9 form gappedly.

The disc spring pressing block 7 is arranged in a disc spring mounting hole of the disc spring seat 9 and plays roles of pressing and guiding the disc spring; the disc spring gland 6 applies pretightening force to the disc spring assembly through the disc spring pressing block 7 and the screw rod assembly 5, a delta 1 gap is formed between the lower end face of the disc spring gland 6 and the upper end face of the disc spring seat 9, the total length L is kept, and the delta 1 is required to be larger than the predicted wedging amount of the opening taper sleeve (the predicted wedging amount is the downward displacement amount of the opening taper sleeve in the first auxiliary hammer taper hole and is determined by considering the elastic deformation of the first auxiliary hammer head, the manufacturing precision of the first auxiliary hammer head and other factors).

Specifically, stop device is including cup jointing spacing collar 3 on main tup 1 and cup jointing the thermal ferrule 4 on 3 excircles of spacing collar, be equipped with the step between 3 excircles of spacing collar and the 4 holes of thermal ferrule, interference fit connection between 3 excircles of spacing collar and the 4 holes of thermal ferrule.

In order to ensure that the thermal ferrule 4 cannot move upwards under impact vibration, a step delta 8 is designed on the outer circle of the limiting ring 3 and the inner hole of the thermal ferrule 4; the outer circle of the limiting ring 3 and the inner hole of the thermal ferrule 4 are designed with single-side interference magnitude alpha, the single-side magnitude of the assembly gap between the limiting ring 3 and the thermal ferrule 4 is set to be beta, the diameter expansion magnitude of the thermal ferrule 4 after being heated is set to be lambda, and the requirement that 2 & ltdelta & gt 8+2 & ltalpha & gt +2 & ltbeta & gt is met.

Specifically, the top of main tup 1 is equipped with the card keyway, install semi-circular stuck key 2 in the card keyway, this semi-circular stuck key 2 and card keyway cooperation, leave the clearance between semi-circular stuck key 2 and the 4 holes of thermal ferrule, this clearance is delta 7.

Assembly sequence of the invention

1. Assembling a hammer body device: the first auxiliary hammer head, the second auxiliary hammer head and the third auxiliary hammer head are sequentially assembled on the main hammer head;

2. assembling an opening taper sleeve: the opening taper sleeve is assembled on the main hammer head and the first auxiliary hammer head;

3. assembling a pre-tightening device: after the pre-tightening device component is pre-assembled, assembling the pre-tightening device component on the main hammer head;

4. assembling a blocking device: assemble the spacing collar on dish spring gland earlier, assemble two semicircles (or many circular arcs) shape card keys in the card keyway of main hammer head again, heat the ferrule to suitable temperature, satisfy when the diameter inflation volume lambda of ferrule: when lambda is more than 2 delta 8+2 alpha +2 beta, the thermal ferrule is rapidly assembled on the limit ring;

5. and when the hot ferrule is cooled to normal temperature, loosening the nut in the pre-tightening screw rod nut component, disassembling the screw rod, and releasing the elasticity of the disc spring to the opening taper sleeve through the disc spring seat.

Working principle of the invention

A. The combined hammer head moves downwards in an accelerated manner: the main hammer head is driven by the oil cylinder to do acceleration motion downwards, the main hammer head transmits the driving force downwards of the oil cylinder to the first auxiliary hammer head, the second auxiliary hammer head and the third auxiliary hammer head in sequence under the combined action of the blocking device, the pre-tightening device and the opening taper sleeve, the synchronous downward acceleration motion of the first auxiliary hammer head, the second auxiliary hammer head, the third auxiliary hammer head and the main hammer head is realized, and the total elastic force F of the spring assembly acts on the opening taper sleeve all the time.

B. Lower anvil block of combined hammer head

At the moment that the main hammer head of the combined hammer head contacts the lower anvil block, the kinetic energy is transmitted to the lower anvil block firstly by the main hammer head rate, because the main hammer head and the auxiliary hammer head are assembled with an elastic gasket and a gap is reserved between the auxiliary hammer head and the auxiliary hammer head, the kinetic energy transmission of the third auxiliary hammer head and the main hammer head lags behind for a period of time, similarly, the kinetic energy transmission between the second auxiliary hammer head and the third auxiliary hammer head and between the first auxiliary hammer head and the second auxiliary hammer head lags behind for a period of time, the effect of prolonging the hammering time and reducing the peak value of stress waves is realized, the impact force born by the pile hammer and the pile is reduced while the transmission efficiency of the impact energy and the pile driving penetration are improved, the service life of the pile hammer is prolonged, and the pile body is protected from being damaged.

When the first auxiliary hammer head, the second auxiliary hammer head and the third auxiliary hammer head transmit kinetic energy to the main hammer head, the gaps delta 4, delta 5 and delta 6 become small, and the gap delta 2 is increased, at the moment, because the total elastic force F of the spring assembly always acts on the opening taper sleeve and pushes the opening taper sleeve to move downwards, the delta 2 is kept unchanged, and the delta 1 is increased.

When the first auxiliary hammer head, the second auxiliary hammer head and the third auxiliary hammer head transmit kinetic energy to the main hammer head, the pre-tightening device consisting of the disc spring gland, the disc spring pressing block, the disc spring assembly, the disc spring seat and the pre-tightening screw nut assembly also has certain kinetic energy, the kinetic energy acts on the opening taper sleeve and applies a wedging force f to the opening taper sleeve downwards, according to the wedge force increasing principle, a positive pressure fz of an inner hole of the opening taper sleeve embracing the main hammer head is amplified, fz is 2 conical taper lambda wedging force f, and finally friction force between the opening taper sleeve and the main hammer head is increased.

C. Rebound prevention of auxiliary hammer

The combined hammer head strikes the lower anvil block, the kinetic energy of the combined hammer head is transmitted to the lower anvil block, on one hand, the lower anvil block transmits part of the kinetic energy to the pile body, and the pile body is driven to penetrate into soil downwards; on the other hand, the kinetic energy of the combined hammer head enables the lower anvil to be elastically deformed (converted into the internal energy of the lower anvil, when the combined hammer head is separated from the lower anvil, the elastic deformation of the lower anvil is reset, and the internal energy is released), and a part of the kinetic energy is converted into heat energy, sound energy and light energy.

When the pile body penetration resistance is proper, most of kinetic energy of the combined hammer head is converted into energy required by the pile body penetration; when the pile body penetration resistance is large, especially when the penetration degree of each hammer is less than 2 mm (this phenomenon is called as 'hammer rejection'), the combined hammer head and the lower anvil block, the main hammer head and the auxiliary hammer head, and the auxiliary hammer head can be impacted like elastic collision, the large rebound force can drive the auxiliary hammer head to move upwards, and then the rebound force is transmitted to the main and auxiliary hammer head connecting devices of other structures, so that the unexpected failure of the connecting devices can be caused. When the opening taper sleeve meets the upward rebound force, the upward rebound force is converted into the rebound force of 2 x lambda times, the holding force (positive pressure) of the opening taper sleeve to the main hammer is larger when the rebound force is larger when the positive pressure and the rebound force are larger, the friction force between the opening taper sleeve and the main hammer is larger, the rebound upward movement of the auxiliary hammer is prevented, the stress of the disc spring and the semicircular clamping key is reduced, and the reliability of the combined hammer connecting mechanism is improved.

In conclusion, the invention prolongs the hammering time, reduces the peak value of the stress wave, improves the transmission efficiency of the impact energy and the pile penetration, reduces the impact force born by the pile hammer and the pile, is beneficial to prolonging the service life of the pile hammer and protects the pile body from being damaged; the reliability of the combined hammer head connecting mechanism is improved; the manufacturing cost of the hammer head of the pile hammer is reduced.

The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.