CN104972438A

CN104972438A - Power tool

Info

Publication number: CN104972438A
Application number: CN201410140189.4A
Authority: CN
Inventors: 杜祥金; 陈志�
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2014-04-10
Filing date: 2014-04-10
Publication date: 2015-10-14
Anticipated expiration: 2034-04-10
Also published as: CN104972438B

Abstract

The invention discloses a power tool which comprises a machine shell, a motor, a sleeve and a chuck. The motor is arranged in the machine shell and outputs rotation power; the sleeve rotates under the drive of the motor; the chuck is used for clamping a work head. The chuck is located in the sleeve and rotates under the drive of the sleeve. The chuck can axially move along the sleeve. The power tool further comprises a limiting mechanism. The limiting mechanism can selectively limit the chuck and allow the chuck to axially move. According to the power tool, different stretching amount of the work head is achieved through different positions of the chuck in the sleeve; quick switching of different working conditions is achieved; the power tool is particularly convenient to operate when used in a narrow space; extra accessories are not needed, and cost is low.

Description

Power tool

Technical Field

The invention relates to a power tool, in particular to a gun drill type power tool which can be used under various working conditions.

Background

Among the existing power tools of the gun drill type, electric drills, electric screwdrivers and impact drills are generally included.

A power screwdriver is a commonly used power tool for tightening screws onto a workpiece. When the screwdriver needs to be operated under different working conditions in the use process, for example, a screw is screwed to a narrow part of a workpiece, because the length of the working head is too short to screw the screw, the longer working head, namely the screwdriver head, needs to be replaced, namely the originally installed working head is taken down and then the long working head is installed, or an accessory adapter is additionally purchased, the working head is installed on the adapter when needed, and then the adapter is installed on the electric screwdriver. In the use occasion that the working head needs to be replaced frequently, great inconvenience is brought to an operator, on one hand, the trouble of replacing the working head or replacing accessories is caused, and on the other hand, the taken-down working head or the adapter is easy to lose everywhere. Some of the hand tools can achieve storage and quick replacement of the working head, but due to the inherent disadvantages of the hand tools, namely, low torque and heavy operation, the operator is easily fatigued and inefficient, and the hand tools are not suitable for being used as professional tools in the industrial industry.

Disclosure of Invention

In view of the shortcomings of the prior art, the invention aims to provide a power tool which can be used under various working conditions.

The technical scheme adopted by the invention for solving the technical problems is as follows: a power tool, comprising: a housing; a motor disposed in the housing and outputting rotational power; a sleeve rotated by the motor; the chuck is used for clamping the working head; the chuck is positioned in the sleeve and driven by the sleeve to rotate, and the chuck can move axially along the sleeve; the power tool also includes a limiting mechanism that selectively limits and allows axial movement of the collet.

Preferably, the collet has a plurality of operating positions axially along the sleeve; the limiting mechanism limits and allows axial movement of the collet in one of a plurality of operating positions.

Preferably, the limiting mechanism comprises a positioning part arranged on the sleeve, a locking part arranged on the chuck, a limiting part capable of locking the positioning part and the locking part, and a limiting control assembly for controlling the limiting part.

Preferably, the positioning part is a positioning hole and is arranged on the inner wall of the sleeve; the locking part is a locking hole; the limiting piece is positioned in the lock hole and can be partially embedded into the lock hole.

Preferably, the chuck has a locking arm at an end of the chuck remote from the working head, the locking hole being provided on the locking arm.

Preferably, the limit control assembly comprises a pushing block capable of moving axially, and the pushing block is provided with a first position and a second position in the axial direction; when the pushing block is axially positioned at the first position, the limiting piece is embedded into the positioning hole; when the pushing block is axially positioned at the second position, the limiting piece is separated from the positioning hole.

Preferably, the limit control assembly further comprises an elastic element capable of enabling the pushing block to reset from the second position to the first position.

Preferably, the pushing block has an abutting surface and a guide surface; when the pushing block is located at the first position, the limiting piece abuts against the abutting surface; when the pushing block is located at the second position, the limiting piece abuts against the guide surface.

Preferably, the guide surface comprises a first guide surface and a second guide surface on either side of the abutment surface.

Preferably, the limit control assembly further comprises a push-pull ring which is sleeved outside the sleeve and drives the pushing block to move along the axial direction of the sleeve.

Preferably, the inner wall of pushing away the pull ring is equipped with the draw-in groove, promote to be equipped with on the piece with draw-in groove assorted joint portion, establish axially extended logical groove on the sleeve, joint portion passes logical groove and extends the sleeve and outer with the draw-in groove joint.

Preferably, the clamping portion is rotatably movable in the clamping groove.

Preferably, the elastic member is a spring.

Preferably, the elastic member includes a first elastic member and a second elastic member; the first elastic piece is fixedly arranged at one end, close to the working head, of the pushing block, and the second elastic piece is fixedly arranged at one end, far away from the working head, of the pushing block.

Preferably, the first elastic member and the second elastic member are disposed in parallel.

Preferably, the first elastic member and the second elastic member are located on the same line.

Preferably, the end of the limiting member has an arc surface.

Preferably, the limiting mechanism further comprises an operating component connected to the casing, and the operating component is operable to control the pushing block to move.

Preferably, the operating assembly comprises an operating part arranged outside the casing and an operating connecting part used for connecting the operating part and the limit control assembly; the operation connecting piece drives the pushing block to move axially along the sleeve.

Compared with the prior art, the invention has the beneficial effects that: the power tool realizes different extension amounts of the working head at different positions of the sleeve through the chuck, realizes quick switching of different working conditions, is particularly used in narrow space, is convenient to operate, does not need to be provided with additional accessories, and is low in cost.

Drawings

Fig. 1 is a schematic sectional view of a power tool according to a preferred embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of the sleeve and its associated parts of the power tool of fig. 1.

Fig. 3 is a schematic sectional view taken along line a-a in fig. 2.

Fig. 4 is a schematic sectional view taken along line B-B in fig. 2.

Figure 5 is a schematic cross-sectional view of the push-pull ring of figure 2 taken along line B-B.

Fig. 6 is a schematic cross-sectional view of the sleeve of fig. 2 taken along line B-B.

Fig. 7 is a schematic sectional view of the locking arm of fig. 2 taken along line B-B.

Figure 8 is an enlarged semi-sectional schematic view of the push-pull block and the resilient member of figure 2.

Fig. 9 is a cross-sectional view of fig. 2 with the collet axially moved forward and with the lock released.

Fig. 10 is a cross-sectional view of fig. 2 with the collet unlocked for axial rearward movement.

Wherein,

1. case 2, motor 3, transmission mechanism

4. Sleeve 5, position limiting mechanism 7, chuck

9. Working head

11. Handle 13, switch button 21, motor shaft

22. Gear box 31, planetary gear mechanism 32, pinion mechanism

301. First gear 302, second gear 303, third gear

40. Axle sleeve 41, positioning hole 42 and through groove

51. Stop 55, locking arm 521, pushing block

525. Push-pull ring 551, lock hole 5211 and abutting surface

5213. First 5215, second 5231, first elastomeric element

5233. Second elastic piece 5251, push-pull ring body 5253, push-pull ring cover

5255. Neck 557 chuck end cap

61. Operating member 63 for operating the connecting member

Detailed Description

In the preferred embodiment of the power tool of the present invention, the power tool is a power screwdriver, which can be classified into a pneumatic screwdriver, a hydraulic screwdriver and an electric screwdriver according to the power source, and the electric screwdriver also has a dc component and an ac component.

Referring to fig. 1, the dc electric screwdriver includes a casing 1, a motor 2, a battery (not shown), a transmission mechanism 3, and a sleeve 4. The casing 1 is assembled by folding two half-shells which are symmetrical left and right by screws (not shown), and has a horizontal part and a handle 11 part which forms an obtuse angle K with the horizontal part, the angle K is preferably between 100 degrees and 130 degrees in the invention, so that the handle 11 can be held comfortably during operation. A push button switch 13 is provided on the upper portion of the handle 11 portion, the battery is fixed to the rear portion of the handle 11 portion, and the transmission mechanism 3 is accommodated in the horizontal portion of the housing 1. As a preferred embodiment, the battery may be a lithium ion battery. It should be noted that the lithium ion battery referred to herein is a generic term of a rechargeable battery based on a lithium ion deintercalation-intercalation reaction, and may be constructed in various systems, such as a "lithium manganese" battery, a "lithium iron" battery, and the like, depending on a positive electrode material. In the present embodiment, the lithium ion battery is a lithium ion battery having a rated voltage of 3.6V (volts). Of course, the battery may also be of the nickel cadmium, nickel hydrogen, or the like, as is well known to those skilled in the art.

The transmission mechanism 3 includes, from back to front (rear on the right side of the drawing), a planetary gear reduction mechanism 31 driven by the motor 2 and a pinion mechanism 32, wherein the pinion mechanism 32 is connected to the sleeve 4 and rotates the sleeve 4. Of course, the sleeve can be directly driven to rotate by the motor according to requirements, and the transmission mechanism is omitted.

The motor 2 in the preferred embodiment of the invention is an electric motor having a motor shaft 21 extending forwardly from the motor housing. The motor is fixed in the casing 1, and a gear box 22 is fixed in the casing 1 at the front of the motor, the gear box 22 being for housing the planetary gear reduction mechanism 31. The pinion gear mechanism 32 includes a first gear 301 connected to the planetary gear reduction mechanism 31 via a gear shaft to transmit torque, a third gear 303 connected to the sleeve 4, and a second gear 302 meshing with both the first gear 301 and the third gear 303, and is disposed such that the rotational axis of the sleeve 4 is parallel to the rotational axis of the motor 2. Of course, the rotational axis of the sleeve 4 may be arranged at an angle relative to the rotational axis of the motor 2, if desired. Wherein the gear shaft may be integrally provided with the first gear 301, the second gear 302 transmits the rotation of the first gear 301 to the third gear 303, and both ends of each gear are supported by bushings. The rear sleeve supporting the pinion mechanism 32 is fixed to the gear case 22, and the front sleeve is fixed to the front housing 13.

Of course, two gears may be provided as required, one being connected to the planetary gear speed reduction mechanism 31 and the other being connected to the sleeve 4. In addition, the transmission mechanism 3 is not limited to the above-described form, and the transmission mechanism 3 may include only the planetary gear speed reduction mechanism 31, or only the pinion gear mechanism 32, or other rotational motion transmission mechanisms such as a ratchet mechanism, a worm gear mechanism, and the like. Wherein the planetary gear speed reducing mechanism 31 has a three-stage speed reducing system, the motor shaft 21 extends to be engaged with the planetary gear speed reducing mechanism 31, the planetary gear speed reducing mechanism 31 transmits the rotation motion to the pinion mechanism 32, and the pinion mechanism 32 drives the sleeve 4 to rotate. When the motor 2 is operated, the motor is finally output from the sleeve 4 through the planetary gear reduction mechanism 31 and the pinion mechanism 32. In addition, the speed reducing mechanism is composed of a three-stage planetary speed reducing system and a two-stage parallel shaft speed reducing system to obtain the desired output speed, and in other embodiments, the speed reducing mechanism may only include a two-stage planetary speed reducing system or other speed reducing systems according to the required output speed.

The outer periphery of the sleeve 4 constitutes at least in part a torque receiving portion which is provided as a hexagonal shaft, i.e. the torque receiving portion has a hexagonal cross-section, and a hexagonal hole is provided in the corresponding third gear 303, and the third gear 303 is an externally meshed cylindrical gear which transmits torque to the sleeve 4 through the hexagonal hole, so that the hexagonal hole constitutes a torque transmitting portion of the third gear 303, and the sleeve 4 is movable within the hexagonal hole and the torque receiving portion of the output shaft is kept meshed with the torque transmitting portion of the third gear 303, so that even when the sleeve 4 has a plurality of operating positions in the axial direction, the sleeve 4 is moved in the axial direction to effect torque transmission, i.e. the third gear 303 transmits rotational power to the sleeve 4.

It is of course possible, if desired, to integrate the third gear with the sleeve, i.e. to have on the outer circumference of the sleeve 4 the teeth of the third gear which directly engage the second gear 302, so as to transmit the rotation of the first gear 301 directly to the sleeve 4.

The sleeve 4 has an inner cavity which accommodates the collet 7 as well as the working head 9, the collet 7 being axially displaceable in the inner cavity of the sleeve 4. The inner cavity of the sleeve 4 can form a torque bearing part, the shape of the chuck 7 is provided with a torque receiving part for receiving the torque from the sleeve 4, the torque bearing part of the sleeve 4 is matched with the torque receiving part of the chuck 7, so that the sleeve 4 transmits the torque to the chuck 7, and the chuck 7 is driven by the sleeve 4 to rotate. The torque receiving portion of the sleeve 4 covers all working positions of the collet 7, i.e. the collet 7 can receive torque from the sleeve 4 in all working positions. Of course, the inner cavity of the sleeve 4 may not be provided with a torque bearing part, and the torque is transmitted to the chuck 7 through the limiting mechanism 5.

The end of the sleeve 4 adjacent the handle 11 is supported on the housing 13 by a bushing 40, the bushing 40 providing radial support for the sleeve 4, although radial support of the sleeve 4 may be provided by bearings.

The front end of the chuck 7 is provided with an axially arranged accommodating hole, the accommodating hole is used for mounting the working head 9, the section of a handle part of a common standard working head is in a regular hexagon shape, namely the handle part forms a torque stress part of the working head, and the accommodating hole is arranged in a hexagonal hole form matched with the torque stress part of the working head 9, so that torque transmission from the chuck 7 to the working head 9 can be realized. Of course, the working head may be non-standard, that is, the cross section of the torque bearing part is polygonal, and the corresponding receiving hole is set to be polygonal matched with the torque bearing part, so that the torque transmission can be realized. In addition, a magnet can be fixedly arranged in the accommodating hole for holding the working head and preventing the working head 9 from falling off when the chuck 7 faces downwards.

In order to enable the electric screwdriver to be operated even in a small space, the chuck 7 is provided to be movable in the axial direction of the sleeve 4. The electric screwdriver is provided with a limiting mechanism 5, and the limiting mechanism 5 can selectively limit and allow the chuck 7 to axially move. Namely, the chuck 7 can be locked or unlocked in the axial direction of the chuck, and when the chuck 7 is locked in the axial direction by the limiting mechanism 5, the chuck 7 is limited from moving in the axial direction; when the stopper mechanism 5 unlocks the cartridge 7 in the axial direction, the cartridge 7 is allowed to move in the axial direction.

The chuck 7 has working positions along the axial direction of the sleeve 4, the limiting mechanism 5 can limit and allow the chuck 7 to move axially at the working positions, and the working positions are different from the casing 1, so that the length of the working head 9 extending out of the casing 1 is adjustable.

Of course, these working positions can be continuous, i.e. axially lockable with the sleeve 4 in any position of the collet 7 within the adjustable range; the working positions can also be discontinuous, that is, the working positions are spaced apart, and in actual use, three or more working positions capable of axially moving and locking the chuck 7 can be set according to requirements.

The distance over which the gripping head 7 can be extended by movement is preferably greater than 25 mm, depending on the actual working environment. Although it is preferable that the chuck 7 is movable by an extended distance as long as possible, in order to make the entire size of the electric screwdriver small and portable, the chuck 7 is movable by an extended distance of less than about 4 inches, i.e., the chuck 7 is movable by an extended distance of less than 101 mm. According to the actual working environment, the length of the working head is preferably 25-101 mm.

The limiting mechanism 5 further comprises a positioning part, a locking part, a limiting part and a limiting control component.

The locating part is arranged on the sleeve, the locking part is arranged on the chuck, and the limiting control assembly controls the limiting part to axially lock or unlock the locating part and the locking part.

When the limiting piece locks the positioning part and the locking part in the axial direction, the sleeve and the chuck are axially locked; when the axial locking between the positioning portion and the locking portion is released, the sleeve and the collet are free to move in the axial direction.

Referring to fig. 2 to 8, the positioning portion is a positioning hole 41 provided on the inner wall of the sleeve 4; the locking part is a locking hole 551 arranged on the chuck 7; the limiting member 51 is located in the lock hole 551 and can be partially inserted into the positioning hole 41.

Specifically, the positioning holes 41 correspond to the operating positions of the chucks 7 one to one. The positioning holes form a positioning hole array which is linearly distributed in parallel to the axial direction of the sleeve. The sleeve 4 is provided with two positioning hole rows which are correspondingly arranged up and down. Of course, the number of the positioning hole rows may be one.

Under the action of the limit control assembly, the limit member 51 arranged on the chuck can be inserted into the positioning hole 41 or removed from the positioning hole 41. When the limiting piece 51 is embedded into the positioning hole 41, the chuck 7 and the sleeve 4 are axially locked, i.e. the chuck 7 cannot axially move in the sleeve 4; when the stopper 51 is disengaged from the positioning hole 41, the collet 7 and the sleeve 4 are axially unlocked, and the collet 7 can axially move within the sleeve 4.

The chuck also has a locking arm 55, the locking arm 55 being disposed at an end of the chuck 7 remote from the working head 9. Of course, the locking arm 55 may be formed separately from the end of the chuck-mounting head to which it is fixedly attached.

Referring to fig. 7, fig. 7 is a schematic cross-sectional view of the locking arm. A locking hole 551 is provided in the locking arm 55, the locking hole 551 is engaged with the positioning hole 41, the locking hole 551 is a through hole penetrating through the locking arm 55, and the stopper 51 passes through the locking hole 551 and is radially movable in the locking hole 551.

When the stopper 51 protrudes from the lock hole 551 and is inserted into the positioning hole 41, one part of the stopper 51 is located in the lock hole 551, and the other part is located in the positioning hole 41, so that the lock arm 55 cannot move axially relative to the sleeve 4; so that the collet 7 cannot move axially relative to the sleeve 4. When the stopper 51 is withdrawn from the positioning hole 41 and retracted into the lock hole 551, the locking of the axial movement between the lock arm 55 and the sleeve 4 is released; so that the collet 7 and the sleeve 4 can move axially.

The lock arm 55 also has a fixing portion to which the elastic member is fixed.

Referring to fig. 2-3 and 8, the positive control assembly further includes an axially movable pusher block 521.

The push block 521 has a first position and a second position in the axial direction; when the pushing block 521 is axially located at the first position, the limiting member 51 is embedded in the positioning hole 41; when the pushing block 521 is located at the second position axially, the limiting member 51 is disengaged from the positioning hole 41.

The pushing block 521 can move axially in the sleeve 4, and the pushing block 521 can convert the axial movement of the pushing block 521 relative to the chuck 7 into the radial movement of the limiting member 51, that is, when the pushing block 521 moves axially relative to the chuck 7, the limiting member 51 moves radially under the action of the pushing block 521, so that the limiting member 51 can be inserted into the positioning hole 41 or removed from the positioning hole 41.

Referring to fig. 8, the push block 521 has an abutment surface 5211 and a guide surface. The abutting surface 5211 is located at the position of the pushing block 521 close to the positioning hole 41; when the pushing block 521 is located at the first position, one end of the limiting member 51 abuts against the abutting surface 5211, and the other end of the limiting member 51 is embedded in the positioning hole 41. When the pushing block 521 is located at the second position, one end of the limiting member 51 abuts against the guiding surface, and the other end of the limiting member 51 is disengaged from the positioning hole 41.

The guide surfaces include a first guide surface 5213 and a second guide surface 5215, and the first guide surface 5213 and the second guide surface 5215 are respectively located on two sides of the abutting surface 5211 and are connected to the abutting surface 5211. The first guide surface 5213 is located on the side closer to the working head 9, and the second guide surface 5215 is located on the side farther from the working head 9. When the collet is moved axially rearward, the first guide surface 5213 abuts against the stop member 51, and when the collet is moved axially forward, the second guide surface 5215 abuts against the stop member 51.

The limit control assembly further comprises an elastic piece. The elastic member is used to restore the pushing block 521 from the second position to the first position. The elastic members further include a first elastic member 5231 and a second elastic member 5233. A first resilient member 5231 is fixed to the push block 521 at a side thereof adjacent to the working head 9, and the other end thereof is fixed to the lock arm 55. A second resilient member 5233 is secured to the push block 521 on the side remote from the working head 9, and is also secured at its other end to the locking arm 55.

The first and second elastic members 5231 and 5233 can exert pressure or tension on the push block 521, so long as it is ensured that when the sleeve 4 is axially locked with the collet 7, the forces of the first and second elastic members 5231 and 5233 are balanced to make the push block 521 axially in a static state. The first and second elastic members 5231 and 5233 are preferably springs.

The first elastic element and the second elastic element can balance the force of the pushing block in the axial direction. Referring to fig. 4, the first elastic member 5231 and the second elastic member 5233 are arranged in parallel, and a first fixing hole for fixing the first elastic member 5231 and a second fixing hole for fixing the second elastic member 5233 are formed in the push block 521.

Of course, the first elastic member and the second elastic member may be located on the same straight line, a first fixing surface for fixing the first elastic member is disposed at the front end of the pushing block 521, and a second fixing surface for fixing the second elastic member is disposed at a position of the pushing block 521 opposite to the first fixing surface.

Of course, the elastic member is not limited to the above-described one, and various embodiments are possible. For example, an elastic member (e.g., a spring) is inserted through and fixed to the pusher block, so that the same effect as described above can be achieved.

Specifically, the end of the limiting member 51 close to the positioning hole 41 has an arc surface, when the positioning hole 41 moves forward or backward axially, the positioning hole 41 presses against the arc surface of the limiting member 51, and the arc structure causes the limiting member 51 to generate a component force toward the axis of the sleeve, so that the radial movement of the limiting member 51 is realized, and the effect of releasing the limiting member 51 from the positioning hole 41 is achieved. Of course, a resilient member for retracting the limiting member 51 radially inward may be provided in the positioning hole 41, so that the limiting member 51 can be disengaged from the positioning hole 41.

The pushing block 521 and the elastic member may be mounted on the locking arm 55, and the locking arm may be a separate structure fixedly connected to the locking arm for convenience of mounting.

Of course, the pushing block 521 and the elastic member are installed in a cavity at one end of the chuck 7 far away from the working head 9. To facilitate the installation of the pusher block 521 and the resilient member into the interior cavity, the collet 7 includes a collet body having a cavity and a collet cap 557 that covers the cavity.

The spacing control assembly further includes a push-pull ring 525. The pulling ring 525 is annularly sleeved outside the sleeve 4. The pushing ring 525 can move axially along the sleeve 4 under the pushing action of an external force, and drives the pushing block 521 to move axially in the sleeve 4.

The pushing ring 525 drives the pushing block 521 to move axially by clamping the pushing block 521.

A through slot 42 is provided in the sleeve 4, which communicates the inner cavity with the outer periphery of the sleeve and extends axially, i.e. the through slot 42 is parallel to the sleeve axis. The through slots 42 are arranged at an angle to the positioning holes 41, i.e. the through slots 42 do not coincide with the positioning holes. Preferably, the through slots 42 are located on the left and right sides of the horizontal position of the sleeve, while the locating holes are located at the top and bottom of the vertical position of the sleeve.

The pushing block 521 has a clamping portion, and the clamping portion is disposed at a position corresponding to the through groove of the pushing block 521. The snap-in portion can slide axially in the through slot 42.

An annular engaging groove 5255 is formed in the inner peripheral surface of the push-pull ring 525. The clamping part of the pushing block 521 passes through the through groove 42 on the sleeve 4 and is clamped in the clamping groove 5255. Since the retaining groove 5255 is annular, the retaining portion can rotate around the axis of the sleeve in the retaining groove 5255.

When the power screwdriver is in the working mode, the sleeve 4, the collet 7, the gripping arms 55 and the pusher block 521 all rotate about the sleeve axis, while the push-pull ring located outside the sleeve does not rotate. Because the joint portion can rotate around the sleeve axis in the clamping groove 5255, the push-pull ring does not influence the axial rotation of the push block.

The number of the clamping parts can be one, two or more. In order to keep the rotating stability, the clamping parts are uniformly distributed on the pushing block.

In order to facilitate the engagement of the engaging portion in the engaging groove 5255, the push-pull ring 525 is composed of a push-pull ring main body 5251 and a push-pull ring cover 5253 which are partitioned by a circular surface of the edge of the engaging groove. Of course, the device can also be composed of two parts separated by other round surfaces; or two semicircular rings separated by a plane passing through the axis.

Of course, the positioning portion, the locking portion, the limiting member, and the limiting member are not limited to the above-described forms, and may have any structure that satisfies the limiting principle of the present invention. For example, the positioning part can also be a positioning column arranged on the sleeve, the limiting part is a cylinder capable of accommodating the positioning column, and the locking part is a cylinder guide groove arranged on the chuck. When the positioning column is embedded into the cylinder column, the chuck and the sleeve are axially locked; when the positioning column is separated from the cylinder column, the chuck and the sleeve are axially unlocked. For example, the positioning portion is a positioning hole provided on the sleeve, the locking portion is a long side of an elastic L-shaped hook fixedly provided on the chuck, the limiting member is a short side of the L-shaped hook, the long side (i.e., the locking portion) of the L-shaped hook is fixed at one end of the chuck far away from the working head, and the short side of the L-shaped hook is a free end and can be inserted into or removed from the positioning hole. The limiting control assembly comprises a wedge-shaped pushing block, when the wedge-shaped pushing block moves towards the direction of the working head along the axial direction, the wedge-shaped pushing block abuts against the corner of the hook, the long edge of the L-shaped hook bends outwards, and the short edge of the L-shaped hook extends outwards in the radial direction to be embedded into the positioning hole; when the wedge-shaped pushing block moves in the direction far away from the working head along the axial direction, the pushing and supporting effect of the wedge-shaped pushing block on the hook is removed, the long edge of the L-shaped hook moves inwards under the action of the elastic force of the L-shaped hook, and the short edge of the L-shaped hook resets inwards to separate from the positioning hole.

The limiting mechanism further comprises an operating component connected to the casing 1, and the operating component is operable to control the pushing block 521 to move.

Further, the operation assembly includes an operation member 61 disposed outside the housing 1 and an operation connector 63 connecting the push-pull ring 525 and the operation member 61. The casing 1 is provided with a slide groove (not shown) extending in the axial direction, and the operating link 63 passes through the slide groove to connect the operating member 61 and the push-pull ring 525 together. The operation connecting member 63 may be a pin, a screw, or the like, or may be a flexible cord or the like. With the arrangement, dust, impurities and the like can be prevented from falling into the machine shell 1, and the flexible sealing strip which does not influence the movement of the connecting piece can be connected to the sliding groove for further enhancing the sealing effect.

Of course, the operation element 61 and the push-pull ring 525 may be integrally provided, and a foldable sealing device may be provided between the operation element 61 and the housing 1 to prevent dust.

The process of rapidly changing the operating state of the chuck in the first embodiment of the electric screwdriver according to the present invention will be described in detail.

When the chuck 7 is at the working position, i.e. the stopper 51 is inserted into the positioning hole 41, the button switch 13 is pressed to perform the screwing operation. At the moment, the motor drives the sleeve to rotate through the transmission mechanism, the sleeve drives the chuck to rotate, and the chuck drives the working head to rotate.

Referring to fig. 2-3 and 9, when the working head 9 needs to be extended into a narrow space for operation, an operator pushes the operation member 61 forward along the sliding slot on the casing 1; the operating piece 61 drives the pulling ring 525 to move forward along the periphery of the sleeve 4; meanwhile, the push block 521 held in the push-pull ring 525 also moves forward, the push block 521 presses the first elastic member 5231 to stretch the second elastic member 5233, and the first and second elastic members 5231, 5233 deform. When the first and second elastic members 5231, 5233 exert a forward force on the locking arm 55, the retaining member 51 located in the locking hole 551 exerts a forward force on the positioning hole 41, and the retaining member 51 is subjected to a reaction force of the positioning hole 41, i.e., the wall of the positioning hole 41 presses the outer end of the retaining member, but the retaining member 51 does not generate a radial displacement because the abutting surface 5211 abuts against the inner end of the retaining member 51. Since the stopper 51 is also inserted into the positioning hole 41, the collet 7 cannot move forward in the axial direction at this time; when the abutting surface 5211 of the push-pull block 521 is moved away from the limiting member 51, the limiting member 51 abuts against and enters the second guiding surface 5215, and since the second guiding surface 5215 is an inclined surface, the limiting member 51 is radially displaced under the extrusion of the positioning hole 41 and retracts toward the axis.

When the stopper 51 is completely disengaged from the positioning hole 41, the locking arm 55 is moved forward by the first and second elastic members 5231, 5233, and the collet 7 is also moved forward.

When the operator releases the forward force on the operation member 61, the first and second elastic members 5231, 5233 generate a force for returning the push block 521 to the initial position. The second guiding surface 5215 of the pushing block 521 presses the stopper 51, and the stopper 51 radially extends out of the lock hole 551 and is inserted into the positioning hole 41, so that the sleeve 4 and the lock arm 55 are axially locked. The push block 521 then continues to move axially rearward until the stop member 51 enters the abutment surface 5211 of the push block 521 and stops moving axially.

At this time, the length of the working head 9 extending out of the casing 1 is large, the working head 9 can extend into a narrow space, and the screw can be screwed by pressing the button switch 13.

Similarly, referring to fig. 2-3 and fig. 10, when the working head 9 needs to be retracted into the housing, the operator pushes the operating member 61 backwards along the sliding slot on the housing 1; the operating piece 61 drives the pulling ring 525 to move backwards along the outer periphery of the sleeve 4; meanwhile, the push block 521 held in the push-pull ring 525 also moves backward, the push block 521 presses the second elastic member 5233 to stretch the first elastic member 5231, and the first and second elastic members 5231, 5233 are deformed. When the first and second elastic members 5231, 5233 exert a backward force on the locking arm 55, the retaining member 51 located in the locking hole 551 exerts a backward force on the positioning hole 41, the retaining member 51 is subjected to a reaction force of the positioning hole 41, i.e., the wall of the positioning hole 41 presses the outer end of the retaining member, but the retaining member 51 does not generate a radial displacement because the abutting surface 5211 abuts against the inner end of the retaining member 51. Since the stopper 51 is also inserted into the positioning hole 41, the collet 7 cannot move axially rearward at this time; when the abutting surface 5211 of the push-pull block 521 moves away from the limiting member 51, the limiting member 51 abuts against and enters the first guiding surface 5213, and since the first guiding surface 5213 is an inclined surface, the limiting member 51 is radially displaced under the extrusion of the positioning hole 41 and retracts toward the axis.

When the stopper 51 is completely disengaged from the positioning hole 41, the locking arm 55 is moved backward by the first and second elastic members 5231, 5233, and the collet 7 is also moved backward.

When the operator releases the backward force to the operation member 61, the first and second elastic members 5231, 5233 generate a force to the push block 521 to return to the original position. The first guiding surface 5213 of the pushing block 521 presses the stopper 51, and the stopper 51 radially extends out of the lock hole 551 and is inserted into the positioning hole 41, so that the sleeve 4 and the lock arm 55 are axially locked. The push block 521 then continues to move axially forward until the stop member 51 enters the abutment surface 5211 of the push block 521 and stops moving axially.

At this time, the length of the working head 9 extending out of the machine shell 1 is small, and the screw can be screwed by pressing the button switch 13.

The above definitions of the various elements are not limited to the various specific configurations or shapes mentioned in the embodiments, and may be easily and commonly replaced by those skilled in the art. For example, the motor can be a gasoline engine or a diesel engine and the like to replace the motor; the working head can be a regular polygon with any cross section. In addition, the limiting mechanism is mainly used for limiting the axial movement of the chuck, the structure of the limiting mechanism is not particularly required, the configuration can be correspondingly changed according to the internal patterns of different shells, new elements can be added, and unnecessary elements can be reduced.

Claims

1. A power tool, comprising:

a housing;

a motor disposed in the housing and outputting rotational power;

a sleeve rotated by the motor;

the chuck is used for clamping the working head;

the method is characterized in that:

the chuck is positioned in the sleeve and driven by the sleeve to rotate, and the chuck can move axially along the sleeve;

the power tool also includes a limiting mechanism that selectively limits and allows axial movement of the collet.

2. The power tool of claim 1, wherein: the chuck is provided with a plurality of working positions along the axial direction of the sleeve; the limiting mechanism limits and allows axial movement of the collet in one of a plurality of operating positions.

3. The power tool according to claim 1 or 2, characterized in that: the limiting mechanism comprises a positioning part arranged on the sleeve, a locking part arranged on the chuck, a limiting part and a limiting control assembly; the limiting control assembly controls the limiting piece to axially lock or unlock the positioning part and the locking part.

4. The power tool of claim 3, wherein: the positioning part is a positioning hole and is arranged on the inner wall of the sleeve; the locking part is a locking hole; the limiting piece is positioned in the lock hole and can be partially embedded into the lock hole.

5. The power tool of claim 4, wherein: the chuck is provided with a locking arm, the locking arm is positioned at one end of the chuck, which is far away from the working head, and the locking hole is formed in the locking arm.

6. The power tool of claim 4, wherein: the limit control assembly comprises a pushing block capable of moving axially, and the pushing block is provided with a first position and a second position in the axial direction; when the pushing block is axially positioned at the first position, the limiting piece is embedded into the positioning hole; when the pushing block is axially positioned at the second position, the limiting piece is separated from the positioning hole.

7. The power tool of claim 6, wherein: the limit control assembly further comprises an elastic piece which can enable the pushing block to reset from the second position to the first position.

8. The power tool of claim 6, wherein: the pushing block is provided with an abutting surface and a guide surface; when the pushing block is located at the first position, the limiting piece abuts against the abutting surface; when the pushing block is located at the second position, the limiting piece abuts against the guide surface.

9. The power tool of claim 8, wherein: the guide surface comprises a first guide surface and a second guide surface which are positioned on two sides of the abutting surface.

10. The power tool of claim 6, wherein: the limiting control assembly further comprises a push-pull ring which is sleeved outside the sleeve and drives the pushing block to move along the axial direction of the sleeve.

11. The power tool of claim 10, wherein: the inner wall of pushing away the pull ring is equipped with the draw-in groove, promote to be equipped with on the piece with draw-in groove assorted joint portion, establish axially extended logical groove on the sleeve, joint portion passes logical groove and extends the sleeve outside with the draw-in groove joint.

12. The power tool of claim 11, wherein: the clamping portion can rotate in the clamping groove.

13. The power tool of claim 4, wherein: the end of the limiting piece is provided with an arc surface.

14. The power tool of claim 6, wherein: the limiting mechanism further comprises an operating component connected to the shell, and the operating component can be used for controlling the pushing block to move in an operating mode.

15. The power tool of claim 14, wherein: the operating assembly comprises an operating part arranged outside the shell and an operating connecting part used for connecting the operating part and the limit control assembly; the operation connecting piece drives the pushing block to move axially along the sleeve.