CN107175628B

CN107175628B - Electric hammer clutch mechanism

Info

Publication number: CN107175628B
Application number: CN201710505014.2A
Authority: CN
Inventors: 张红松; 姚仰华; 刘晓钟
Original assignee: Huali Electric Manufacturing Co ltd
Current assignee: Huali Electric Manufacturing Co ltd
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2023-06-13
Anticipated expiration: 2037-06-28
Also published as: CN107175628A

Abstract

The utility model relates to an electric hammer clutch mechanism which comprises a gearbox, an upper cover, a knob assembly, a drilling clutch assembly and a hammering clutch assembly. The knob assembly is arranged on the upper cover and comprises a knob and an eccentric seat, a poking pin is arranged on the end face of the eccentric seat, which is far away from the knob, and the drilling clutch assembly is driven by the poking pin. The side of eccentric seat still is equipped with first promotion boss, and first promotion boss changes hammering clutch assembly's position. By adopting the structure, when the knob is rotated, the poking pin of the eccentric seat pokes the drilling clutch component to realize the clutch of the drilling operation of the electric hammer, and meanwhile, the first lifting boss of the eccentric seat drives the hammering clutch component to realize the clutch of the hammering operation of the electric hammer. Therefore, four functions of controlling the hammer, the drill, the hammer drill and the flat chisel angle by one knob can be realized, the operation of a user is convenient, and the market application prospect is wide.

Description

Electric hammer clutch mechanism

Technical Field

The utility model relates to an electric hammer clutch mechanism, in particular to an electric hammer single-knob double-clutch mechanism.

Background

The electric hammer is a common electric tool, and with the development of the electric tool industry, the requirements on the functions of the electric hammer are higher and higher.

The principle of the electric hammer is that the transmission mechanism drives the drill bit to do rotary motion and simultaneously has reciprocating hammering motion with the direction perpendicular to the rotary head. The electric hammer is characterized in that a driving mechanism drives a piston to reciprocate in a cylinder to compress air, and the air pressure in the cylinder is periodically changed to drive a hammer in the cylinder to reciprocate to strike the top of a brick, so that the electric hammer is named as if the hammer is used for striking the brick. The electric hammer is favored by the vast users because of having four functions of single hammer, single drill, hammer drill and flat chisel angle adjustment.

According to different hammering transmission structures, the electric hammers can be divided into swing rod bearing type electric hammers and crankshaft type electric hammers. The oscillating bar bearing type electric hammer is mainly used in light load occasions, and the patent of the utility model with the authority of publication number CN204295648U discloses a single-knob multifunctional electric hammer, so that the purpose of controlling four functions (hammer, drill, hammer drill and flat chisel angle adjustment) by one knob of the oscillating bar bearing type electric hammer is realized. However, as a more mainstream crankshaft type electric hammer in the market, a double-knob double-clutch structure is generally adopted, a mature clutch mechanism is not generated all the time, and one knob can control four functions.

Disclosure of Invention

The technical problem to be solved by the utility model is to provide the single-knob double-clutch mechanism which realizes four functions of controlling the hammer, the drill, the hammer drill and the flat chisel angle by one knob, and has the advantages of simple structure and convenience in processing and manufacturing.

In order to solve the technical problems, the technical scheme provided by the utility model is as follows:

an electric hammer clutch mechanism comprises a gearbox, an upper cover, a knob assembly, a drilling clutch assembly and a hammering clutch assembly. The upper cover is fixedly arranged on the gearbox to form a cavity; the knob assembly is arranged on the upper cover and comprises a knob and an eccentric seat, the eccentric seat is detachably connected with the knob, a poking pin is arranged on the end surface of the eccentric seat, which is far away from the knob, and the drilling clutch assembly is driven by the poking pin; the hammering clutch assembly comprises a crankshaft, and a first key groove is formed in the crankshaft. The side of eccentric seat still is equipped with first promotion boss, and one side that first promotion boss faced the knob is equipped with first domatic. The hammering clutch assembly further comprises an impact gear, an impact clutch disc, a first elastic element, a hammering clutch support, a second elastic element and a support seat. The impact gear is arranged on the crankshaft to form clearance fit, and the end face of the impact gear is also provided with a groove; the impact clutch disc is provided with a first key hole in the center, and can move along the first key groove; the end face of the impact clutch disc is also provided with a bulge which is matched with the groove; a first flange is arranged around the impact clutch disc; the first elastic element is arranged between the crankshaft and the impact clutch disc; the hammering clutch bracket comprises a clutch fork and a guide post vertically fixed on the clutch fork, a guide hole is formed in the gearbox, and the guide post is arranged in the guide hole and can move along the guide hole; the clutch fork is provided with a notch for accommodating the impact clutch disc, and the size of the notch is smaller than that of the flange; the second elastic element is arranged between the hammering clutch bracket and the gearbox; the bracket seat and the hammering clutch bracket are detachably and fixedly installed; the support seat is provided with a second lifting boss, one side of the second lifting boss facing the gearbox is provided with a second slope, and the first slope is gradually wedged below the second slope when the knob is rotated so that the support seat is lifted.

By adopting the structure, when the knob is rotated, the poking pin of the eccentric seat pokes the drilling clutch component to realize the clutch of the drilling operation of the electric hammer, and meanwhile, the first lifting boss of the eccentric seat drives the hammering clutch component to realize the clutch of the hammering operation of the electric hammer. Therefore, four functions of controlling the hammer, the drill, the hammer drill and the flat chisel angle by one knob can be realized, the operation of a user is convenient, and the market application prospect is wide.

Further, the guide posts of the hammering clutch bracket are cylindrical, and two guide posts are respectively positioned at two ends of the clutch fork. The hammering clutch bracket adopts the structure, the guide column can realize good guide effect, and the processing technology is simple and the manufacturing cost is low on the premise of realizing the function.

Further, the second elastic element is a compression spring, and the compression spring is sleeved on the guide post. The pressure spring is arranged on the guide post, so that the installation problem of the pressure spring is solved.

Further, the support seat is door-shaped, and the support seat includes two shank and a crossbeam, and shank center is equipped with the centre bore that supplies the guide post to insert the installation, and the second promotes the boss setting at crossbeam side middle part, and the support seat adopts the spiro union with hammering separation and reunion support. The guide post of hammering separation and reunion support and the centre bore installation cooperation of shank form a stable frame construction, and the structure is reliable. The design of spiro union guarantees that the connection of a support seat and hammering separation and reunion support can be repeatedly dismantled, connects firmly simultaneously.

Further, the groove of the impact gear comprises a landslide part and a clamping part, the landslide part inclines from the end face of the impact gear to the clamping part to form a landslide, the clamping part is a flat-bottomed groove, and a step is formed at the joint of the landslide part and the clamping part. By adopting the design, the impact force generated when the impact clutch disc is meshed with the impact gear can be reduced, and the impact clutch disc has a buffering effect.

Further, the number of grooves is 3. The transmission of moment of torsion can be guaranteed to set up 3 recesses, improves the life who strikes the clutch disc.

Further, the first elastic element is a tower spring, and the tower spring is sleeved on the crankshaft. When the tower spring is compressed, the tower spring can be stacked into a mosquito-repellent incense shape in one plane, so that the occupied axial distance is greatly reduced, and the design space is more compact and reasonable.

Further, the impact clutch disc is cylindrical, and the notch of the clutch fork is semicircular. The revolving body workpiece is simple to process and easy to manufacture.

Further, the first key groove is a spline groove, and the first splined hole is a splined hole. The spline guidance quality is good, and impact clutch plate can slide along spline groove flexibility, and transmission torque is big simultaneously, work piece long service life.

Further, the drilling clutch assembly comprises a cylinder, a bevel gear, a clutch sleeve, a locking plate, a drilling clutch bracket and a torsion spring. The cylinder is rotatably arranged in the gearbox, and a second key slot is further formed in the outer side of one end, close to the crankshaft, of the cylinder; the bevel gear is arranged on the air cylinder to form clearance fit, and one end of the bevel gear is also provided with a first end face tooth; a second keyhole matched with the second key slot is arranged in the clutch sleeve, one end of the clutch sleeve, which is close to the bevel gear, is provided with second end face teeth, the other end of the clutch sleeve is provided with third end face teeth, and a second flange is further arranged on the outer cylindrical surface of the clutch sleeve; the locking plate is fixedly arranged on the gearbox, and an internal tooth hole matched with the third end face tooth is also formed in the locking plate; a ring groove for accommodating the second flange is formed in the drilling clutch bracket; the spiral part of the torsion spring is sleeved on the upright post at one side of the drilling clutch support, two ends of the torsion spring extend to form leg parts, the leg parts are fixed at the other side of the drilling clutch support in parallel, and the poking pin is positioned between the two leg parts.

In a word, the single-knob double-clutch mechanism realizes four functions of controlling the angles of the hammer, the drill, the hammer drill and the flat chisel by one knob, and has a simple structure and is convenient to process and manufacture.

Drawings

FIG. 1 is an assembly view of the clutch mechanism of the electric hammer of the present embodiment;

fig. 2 is a schematic structural view of the electric hammer clutch mechanism without a gearbox and an upper cover, and further includes a connecting rod and a piston for easy understanding;

fig. 3 is an exploded schematic view of the clutch mechanism of the electric hammer according to the present embodiment, and for convenience of understanding, the electric hammer further includes a connecting rod and a piston;

fig. 4 is a sectional view showing a flat chisel angle adjustment state of the electric hammer clutch mechanism of the present embodiment;

fig. 5 is a sectional view showing a state of a hammer drill of the electric hammer clutch mechanism of the present embodiment;

fig. 6 is a sectional view of the electric hammer clutch mechanism of the present embodiment in a drilling state;

fig. 7 is a schematic structural view of a hammering clutch bracket according to the embodiment;

fig. 8 is a schematic structural view of the stand base of the present embodiment;

fig. 9 is a schematic structural view of an impact gear of the present embodiment;

FIG. 10 is a schematic view of the impact clutch plate according to the present embodiment;

FIG. 11 is a schematic view of the assembly of the present embodiment drilling clutch assembly parts and knob assembly;

FIG. 12 is an exploded view of the present embodiment drilling clutch assembly and knob assembly;

the gear box-1, an upper cover-2, a knob assembly-3, a knob-31, an eccentric seat-32, a poking pin-32 a, a first lifting boss-32 b, a drilling clutch assembly-4, a torsion spring-40, a drilling clutch bracket-41, a clutch sleeve-42, a bevel gear-43, a cylinder-44, a locking plate-45, a hammering clutch assembly-5, a crankshaft-51, a first key groove-51 a, a percussion gear-52, a groove-52 a, a percussion clutch disc-53, a first keyed hole-53 a, a protrusion-53 b, a first flange-53 c, a first elastic element-54, a hammering clutch bracket-55, a clutch fork-55 a, a guide post-55 b, a second elastic element-56, a bracket seat-57, a second lifting boss-57 a, a leg-57 b and a cross beam-57 c.

Detailed Description

The present utility model will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present utility model more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

An electric hammer clutch mechanism as shown in fig. 1, 2 and 3 comprises a gearbox 1, an upper cover 2, a knob assembly 3, a drilling clutch assembly 4 and a hammering clutch assembly 5. The upper cover 2 is fixedly arranged on the gearbox 1 to form a cavity; the knob assembly 3 is installed on the upper cover, and the knob assembly 3 includes knob 31 and eccentric seat 32, and eccentric seat 32 and knob 31 can dismantle the connection, and the terminal surface that eccentric seat 32 kept away from knob 31 is equipped with dials the round pin 32a, and the side of eccentric seat 32 still is equipped with first promotion boss 32b, and first promotion boss 32b is equipped with first domatic in one side of facing knob 31. The drilling clutch assembly 4 is driven by a poking pin 32 a; the hammer clutch assembly 5 includes a crankshaft 51, and a first key groove 51a is provided in the crankshaft 51.

The hammer clutch assembly 5 further comprises an impact gear 52, an impact clutch disc 53, a first elastic element 54, a hammer clutch carrier 55, a second elastic element 56 and a carrier seat 57.

The impact gear 52 is mounted on the crankshaft 51 to form a clearance fit, and the end face of the impact gear 52 is further provided with a groove 52a. As shown in fig. 9, the groove 52a of the impact gear 52 includes a sliding portion inclined from the end of the impact gear toward the engagement portion to form a sliding surface, the engagement portion is a flat-bottomed groove, and a step is formed at the junction of the sliding portion and the engagement portion. By adopting the design, the impact force generated when the impact clutch disc is meshed with the impact gear can be reduced, and the impact clutch disc has a buffering effect. In this embodiment, the number of grooves 52a is 3. The provision of 3 grooves 52a ensures torque transmission and increases the service life of the impact clutch plate 53.

The center of the impact clutch plate 53 is provided with a first key hole 53a, and the impact clutch plate 53 can move along the first key groove 51 a; the end face of the impact clutch plate 53 is also provided with a protrusion 53b, and the protrusion 53b is matched with the groove 52 a; a first flange 53c is also provided around the impact clutch plate 53. As shown in fig. 10, the impact clutch plate 53 is cylindrical. The revolving body workpiece is simple to process and easy to manufacture. Correspondingly, as shown in fig. 7, the notch of the clutch fork 55b is semicircular. In this embodiment, the first key groove 51a is a spline groove, and the first splined hole 53a is a splined hole. The spline guidance quality is good, and impact clutch plate can slide along spline groove flexibility, and transmission torque is big simultaneously, work piece long service life.

The first elastic element 54 is disposed between the crankshaft 51 and the impact clutch disc 53, and in this embodiment, the first elastic element 54 is a torsion spring, and the torsion spring is sleeved on the crankshaft 51. When the tower spring is compressed, the tower spring can be stacked into a mosquito-repellent incense shape in one plane, so that the occupied axial distance is greatly reduced, and the design space is more compact and reasonable.

The hammering clutch bracket 55 comprises a clutch fork 55a and a guide post 55b vertically fixed on the clutch fork 55a, a guide hole is arranged on the gearbox 1, and the guide post 55b is arranged in the guide hole and can move along the guide hole; the clutch fork 55a is provided with a notch for receiving the impact clutch plate 53, the notch being smaller in size than the flange 53c. As shown in fig. 7, the guide posts 55b of the hammer clutch bracket 55 are cylindrical, and two guide posts 55b are respectively positioned at two ends of the clutch fork 55 a. The hammering clutch bracket 55 adopts such a structure, the guide column 55b can realize a good guide effect, and the processing technology is simple and the manufacturing cost is low on the premise of realizing the function.

The second elastic member 56 is installed between the hammer clutch bracket 55 and the transmission case 1. The second elastic element 56 is a compression spring, and the compression spring is sleeved on the guide post 55 b. The compression spring is arranged on the guide post 55b, so that the installation problem of the compression spring is solved. The provision of the second elastic member 56 also solves the problem of returning the hammer clutch bracket 55.

The bracket seat 57 and the hammering clutch bracket 55 are detachably and fixedly installed, and the bracket seat 57 and the hammering clutch bracket 55 are respectively positioned at two sides of the gearbox 1; the support base 57 is provided with a second lifting boss 57a, one side of the second lifting boss 57a facing the gearbox 1 is provided with a second slope, and when the knob 31 is rotated, the first slope is gradually wedged under the second slope so that the support base 57 is lifted. In this embodiment, as shown in fig. 8, the support base 57 is in a door shape, the support base 57 includes two leg portions 57b and a cross beam 57c, a center hole for inserting and installing the guide post 55b is provided in the center of the leg portion 57b, and the second lifting boss 57a is provided in the middle of the side face of the cross beam 57c. The guide post 55b of the hammering clutch bracket 55 is matched with the central hole of the leg 57b in a mounting way to form a stable frame structure, and the structure is reliable. The hammering clutch holder support 57 is screwed with the hammering clutch holder 55. The design of the screw connection ensures that the connection of the bracket seat 57 and the hammering clutch bracket 55 can be repeatedly detached, and the connection is stable.

As shown in fig. 11 and 12, the drill clutch assembly includes a cylinder 44, a bevel gear 43, a clutch sleeve 42, a locking plate 45, a drill clutch bracket 41, and a torsion spring 40. The cylinder 44 is rotatably arranged in the gearbox 1, and a second key groove is formed in the outer side of one end, close to the crankshaft 51, of the cylinder 44; the bevel gear 43 is arranged on the cylinder 44 to form clearance fit, and one end of the bevel gear 43 is also provided with a first end face tooth; a second keyhole matched with the second key slot is arranged in the clutch sleeve 42, one end of the clutch sleeve 42 close to the bevel gear 43 is provided with second end face teeth, the other end of the clutch sleeve 42 is provided with third end face teeth, and a second flange is also arranged on the outer cylindrical surface of the clutch sleeve 42; the locking plate 45 is fixedly arranged on the gearbox 1, and an internal tooth hole matched with the third end face tooth is also formed in the locking plate 45; a ring groove for accommodating the second flange is formed in the drilling clutch bracket 41; the spiral part of the torsion spring 40 is sleeved on the upright post at one side of the drilling clutch support 41, two ends of the torsion spring 40 extend to form leg parts, the leg parts are fixed at the other side of the drilling clutch support 41 in parallel, and the poking pin 32a is positioned between the two leg parts.

The following describes the structure in detail with reference to specific knob positions:

as shown in fig. 4, when the knob 31 is in the flat chisel angle adjustment state, the poking pin 32a of the eccentric seat 32 pokes the torsion spring 40 to drive the drilling clutch support 41, the second flange on the outer cylindrical surface of the clutch sleeve 42 is accommodated in the annular groove of the drilling clutch support 41, the drilling clutch support 41 controls the second end face teeth of the clutch sleeve 42 to be separated from the first end face teeth of the bevel gear 43, and the bevel gear 43 and the air cylinder 44 are in clearance fit and cannot drive the air cylinder 44 to move; at this time, the first lifting boss 32b of the eccentric seat 32 is located at the left side of the eccentric seat 32, the bracket seat 57 and the hammering clutch bracket 55 are located at a low position under the action of the second elastic element 56, the impact clutch disc 53 is meshed with the impact gear 52, the power is transmitted to the clutch disc 53 by the impact gear 52, and then transmitted to the crankshaft 51 by the clutch disc 53 through a key, and the crankshaft 51 drives the connecting rod piston to realize hammering;

as shown in fig. 5, when the knob 31 is in the hammer drilling state, the poking pin 32a of the eccentric seat 32 pokes the drilling clutch support 41, the drilling clutch support 41 controls the second end face teeth of the clutch sleeve 42 to be connected with the first end face teeth of the bevel gear 43, the bevel gear 43 transmits power to the clutch sleeve 42, and the clutch sleeve 42 moves to the air cylinder 44, so that the air cylinder 44 is driven to move to realize drilling work; meanwhile, the first lifting boss 32b of the eccentric seat 32 is positioned at the inner side, the bracket seat 57 and the hammering clutch bracket 55 are still positioned at a low position under the action of the second elastic element 56, the impact clutch disc 53 is meshed with the impact gear 52, power is transmitted to the clutch disc 53 by the impact gear 52, and then transmitted to the crankshaft 51 by the clutch disc 53 through a key, and the crankshaft 51 drives the connecting rod piston to realize hammering;

as shown in fig. 6, when the knob 31 is in the single-drill state, the poking pin 32a of the eccentric seat 32 pokes the drilling clutch support 41, the second end face teeth of the clutch sleeve 42 controlled by the drilling clutch support 41 are connected with the first end face teeth of the bevel gear 43, the bevel gear 43 transmits power to the clutch sleeve 42, and the clutch sleeve 42 moves to the air cylinder 44, so that the air cylinder 44 is driven to move to realize drilling work; meanwhile, the first lifting boss 32b of the eccentric seat 32 is positioned on the right side, the bracket seat 57 and the hammering clutch bracket 55 are lifted under the action of the first lifting boss 32b, the hammering clutch bracket 55 lifts the impact clutch plate 53, the impact clutch plate 53 is separated from the impact gear 52, power cannot be transmitted to the clutch plate 53 by the impact gear 52, and hammering operation is stopped;

the knob 31 is in the single hammer state similar to the clutch state when the knob 31 is in the flat chisel angle adjustment state, the only difference being that when the knob 31 is in the single hammer state, the drill clutch bracket 41 toggles the clutch sleeve 42 to the right so that the third end face teeth of the clutch sleeve 42 are engaged with the inner tooth holes of the locking plate 45. Because the locking plate 45 is fixed with the gearbox, the clutch sleeve 42 matched with the locking plate is fixed, the air cylinder 44 is also fixed, and the cutter can not rotate during hammering operation, so that a single hammer state is realized. The transmission principle is not described here, as shown in fig. 4, 5 or 6.

By adopting the structure, when the knob 31 is rotated, the poking pin 32a of the eccentric seat 32 pokes the drilling clutch component 4, so that the electric hammer drilling operation is clutched, and meanwhile, the first lifting boss 32b of the eccentric seat 32 drives the hammering clutch component, so that the electric hammer hammering operation is clutched. Therefore, four functions of controlling the hammer, the drill, the hammer drill and the flat chisel angle by one knob can be realized, the operation of a user is convenient, and the market application prospect is wide.

In summary, the foregoing description is only of the preferred embodiments of the utility model, and is not intended to limit the utility model to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the utility model.

Claims

1. An electric hammer clutch mechanism comprises

-a gearbox;

-an upper cover fixedly mounted on the gearbox forming a cavity;

a knob assembly mounted on the upper cover, the knob assembly comprising a knob and an eccentric seat detachably connected to the knob, the end surface of the eccentric seat remote from the knob being provided with a poking pin;

-a drilling clutch assembly, said drilling clutch assembly being driven by a poking pin;

-a hammer clutch assembly comprising a crankshaft having a first keyway provided thereon;

the method is characterized in that: the side of eccentric seat still is equipped with first promotion boss, first promotion boss is equipped with first domatic to one side of knob, hammering clutch subassembly still includes

-an impact gear mounted on the crankshaft forming a clearance fit, the impact gear end face being further provided with a groove;

-an impulse clutch disc provided with a first splined opening in the centre thereof, said impulse clutch disc being movable along a first keyway; the end face of the impact clutch disc is also provided with a bulge, and the bulge is matched with the groove; a first flange is arranged around the impact clutch disc;

-a first elastic element arranged between the crankshaft and the impact clutch disc;

-a hammering clutch support comprising a clutch fork and a guide post vertically fixed on the clutch fork, the gearbox being provided with a guide hole, the guide post being mounted in the guide hole and being movable along the guide hole; the clutch fork is provided with a notch for accommodating the impact clutch disc, and the size of the notch is smaller than that of the first flange;

-a second elastic element mounted between the hammering clutch support and the gearbox;

-a carrier seat detachably fixedly mounted with the hammering clutch carrier; the support seat is provided with a second lifting boss, one side of the second lifting boss facing the gearbox is provided with a second slope, and the first slope is gradually wedged below the second slope when the knob is rotated so that the support seat is lifted.

2. The electric hammer clutch mechanism according to claim 1, wherein: the guide posts of the hammering clutch support are cylindrical, and two guide posts are respectively positioned at two ends of the clutch fork.

3. The electric hammer clutch mechanism according to claim 2, wherein: the second elastic element is a pressure spring, and the pressure spring is sleeved on the guide post.

4. A hammer clutch mechanism according to claim 3, wherein: the support seat is door-shaped and comprises two leg parts and a cross beam, a central hole for the guide post to be inserted and installed is formed in the center of each leg part, and the second lifting boss is arranged in the middle of the side face of the cross beam; the support seat is in threaded connection with the hammering clutch support.

5. The electric hammer clutch mechanism according to any one of claims 1 to 4, wherein: the groove of the impact gear comprises a landslide part and a clamping part, the landslide part inclines from the end face of the impact gear to the clamping part to form a landslide, the clamping part is a flat-bottomed groove, and a step is formed at the joint of the landslide part and the clamping part.

6. The electric hammer clutch mechanism according to claim 5, wherein: the number of the grooves is 3.

7. The electric hammer clutch mechanism according to claim 6, wherein: the first elastic element is a tower spring, and the tower spring is sleeved on the crankshaft.

8. The electric hammer clutch mechanism according to claim 7, wherein: the impact clutch disc is cylindrical, and the notch of the clutch fork is semicircular.

9. The electric hammer clutch mechanism according to claim 8, wherein: the first key groove is a spline groove, and the first splined hole is a splined hole.

10. The electric hammer clutch mechanism according to claim 9, wherein: the drilling clutch assembly comprises

-a cylinder rotatably mounted in the gearbox, the cylinder being further provided with a second keyway on the outside of one end near the crankshaft;

a bevel gear mounted on the cylinder forming a clearance fit, one end of the bevel gear being further provided with first end face teeth;

a clutch sleeve, wherein a second keyed hole matched with a second key groove is formed in the clutch sleeve, a second end face tooth is formed at one end, close to the bevel gear, of the clutch sleeve, a third end face tooth is formed at the other end of the clutch sleeve, and a second flange is further arranged on the outer cylindrical surface of the clutch sleeve;

-a locking plate fixedly mounted on the gearbox, said locking plate being further provided with an internal tooth aperture therein for cooperation with the third end tooth;

-a drilling clutch support having a groove therein for receiving the second flange;

the spiral part of the torsion spring is sleeved on the upright post at one side of the drilling clutch support, two ends of the torsion spring extend to form leg parts, the leg parts are parallelly fixed at the other side of the drilling clutch support, and the poking pin is positioned between the two leg parts.