A quick clamping device and a multifunctional machine tool using the same

Abstract

The present invention relates to a tool quick clamping device for a handheld electric tool, and belongs to the technical field of electric tools. The device comprises a vertical hollow output shaft and a pull rod with an expansion cone at the lower end; a slide groove which forms a vertical moving pair with a hinge pin is formed in the middle of the pull rod, and the hinge pin is hingedly mounted to the upper part of the left and right chucks on both sides of the pull rod; the inner side of the lower end of the left and right chucks matches the expansion cone; the upper end of the left chuck and the right chuck are in contact with the small spring sleeved on the pull rod, and the upper end of the small spring is in contact with the pressing device that presses the pull rod, and the pressing device is also in contact with the upper end of the large spring, and the lower end of the large spring is limited to the output shaft. The present invention is completely released and will not get stuck; and during the tightening process, the relative action of the large spring on the pull rod and the small spring on the left and right chucks causes the expansion cone to produce a strong tightening effect, so the clamping of the tool is very reliable.

Description

Technical Field

[0001] The invention relates to a tool quick clamping device for a handheld electric tool and also relates to a multifunctional machine tool adopting the device, belonging to the technical field of electric tools. Background Art

[0002] The output shaft of the multifunctional machine tool swings around its own axis, driving the working head (including straight saw blades, circular saw blades, triangular sanding discs and shovel-shaped scrapers) installed at the end of the shaft to move accordingly, which can realize sawing, cutting, grinding, scraping and other operations. It is a commonly used handheld electric tool, and its typical structure is disclosed in the Chinese invention patent application number 201380021580.6. The machine has a housing extending roughly along the longitudinal axis direction, and the housing has a gripping area, which is configured for the user to grasp and guide the machine tool with one hand. The machine tool includes an electric drive unit and a tool device roughly accommodated in the housing, and the tool device is roughly mechanically decoupled from the housing. The housing has a center of gravity, which is arranged in a cross section along the longitudinal axis in relation to the length of the housing, and the cross section extends from the geometric center of the housing to the rear side.

[0003] According to the applicant's understanding, since various types or specifications of tools often need to be replaced as appropriate during the use of existing multifunctional machine tools, the quick clamping device of tools such as saw blades and grinding heads is crucial to the performance of the multifunctional machine tools.

[0004] According to the search, the Chinese patent document with application number 201480043554.8 discloses a manually guided machine tool, which has a tool receiving device that can move around a drive shaft, especially can oscillate, so as to hold the tool device on the machine tool. The tool receiving device has at least one tensioning device, at least one holding device and at least one locking device. The holding device can move from at least one first open position to at least one second closed position. In addition, the holding device can preferably be tensioned by the tensioning device along the closing direction from the first open position to the second closed position. The locking device can move between at least one first locked position and at least one second unlocked position. Here, the movement of the holding device can be prevented at least one locked position by the locking device. The locking device is moved from a locked position to an unlocked position by the force indirectly or directly applied to the locking device by the tool device. Although the tool receiving device containing tensioning, holding and locking in this technical solution can quickly and easily install the tool in the machine tool, it is obvious that the manufacturing and assembly process is poor, especially its holding device, which has a complex geometry and is difficult to process.

[0005] In addition, Chinese patent documents with application numbers 201510120755.X and 201610221396.1 respectively disclose a multifunctional tool quick-change structure that can perform various operations such as cutting and sanding, and a quick-change multifunctional saw structure. The technical solutions of these two patents both use an elastic chuck structure to achieve rapid clamping of the tool. Therefore, after use, the elastic chuck will inevitably be fatigued and damaged due to repeated elastic deformation and recovery, and its service life is limited. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to provide a tool quick clamping device which is not only simple in structure and has good manufacturing process but also can avoid fatigue damage, and at the same time to provide a multifunctional machine tool using the device.

[0007] In order to achieve the above purpose, the basic technical scheme of the tool quick clamping device of the present invention is as follows: it includes a rotatable vertical hollow output shaft fixedly connected to the output shaft base and a liftable pull rod located in the output shaft; the lower end of the pull rod has a support cone, and the middle part is provided with a slide groove which forms a vertical moving pair with a hinge pin, and the hinge pin is hingedly mounted to the upper part of the left chuck and the right chuck on both sides of the pull rod; the lower ends of the left chuck and the right chuck extend out of the central hole of the output shaft base, and the inner sides of the lower ends of the left chuck and the right chuck match the support cone, and the outer sides match the mounting hole of the tool to be clamped;

[0008] The pressing device has an upper limit position and a lower limit position; when in the lower limit position, the downward movement stroke of the pull rod is greater than the left chuck and the right chuck, so that the left chuck and the right chuck are in a released state with their lower ends separated from the expansion cone; when in the upper limit position, the pull rod is elastically lifted so that the left chuck and the right chuck are in a tensioned state with their lower ends expanded by the expansion cone.

[0009] In particular, the upper ends of the left and right chucks are in contact with the small spring sleeved on the pull rod, the upper end of the small spring is in contact with the pressing device that presses the pull rod, and the pressing device also is in contact with the upper end of the large spring, and the lower end of the large spring is limited to the output shaft; when in the upper limit position, the pull rod is lifted by the large spring whose elastic coefficient is greater than that of the small spring, so that the left and right chucks are in a tensioned state with their lower ends stretched open by the expansion cone.

[0010] The present invention realizes quick disassembly and assembly of the tool by utilizing the downward movement of the lower ends of the left and right chucks for loosening and the upward movement for tightening. Since the upper ends of the left and right chucks are hinged, the lower ends can open and close sensitively, and in the releasing process, the slide groove structure of the pull rod realizes the over-travel downward movement of the pull rod relative to the left and right chucks, so the release is complete and no jamming occurs. In the tightening process, the relative effects of the large spring on the lifting of the pull rod and the small spring on the downward pressing of the left and right chucks cause the expansion cone to produce a strong tightening effect, so the clamping of the tool is very reliable.

[0011] The multifunctional machine tool adopting the tool quick clamping device of the present invention comprises a shell with a motor placed in the middle and a transmission box installed in the front, the motor is connected to the output shaft through a swing transmission mechanism, and the transmission box is composed of a vertical part supporting the output shaft and a horizontal part for placing the motor and the transmission mechanism; the vertical part is equipped with the tool quick clamping device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be further described below in conjunction with the accompanying drawings.

[0013] Figure 1 It is a three-dimensional structural schematic diagram of the multifunctional machine tool of the present invention.

[0014] Figure 2 yes Figure 1 Schematic diagram of the top view of the tool locking state in the embodiment.

[0015] Figure 3 yes Figure 2 Schematic diagram of the BB cross-sectional structure.

[0016] Figure 4 yes Figure 1 Schematic diagram of the top view of the tool in the released state of the embodiment.

[0017] Figure 5 yes Figure 4 Schematic diagram of the BB cross-sectional structure.

[0018] Figure 6 yes Figure 1 Schematic diagram of the three-dimensional exploded structure of the tool quick clamping device.

[0019] In the figure: screw 1, handle 2, retaining ring 3, handle pressure cover 4, rotating seat 5, pressure block 6, transmission box 7, retaining ring 8, upper bearing 9, output shaft 10, skeleton oil seal 12, needle bearing 13, nut 14, spring washer 15, upper gasket 16, large spring 17, small spring 18, lower gasket 19, pull rod 20, hinge pin 21, left chuck 22, right chuck 23, saw blade 24, shift fork 25, spherical bearing 27, bearing seat 31, front bearing 32, eccentric shaft 33, motor stator assembly 34, motor rotor assembly 35, rear bracket 36, housing 39. DETAILED DESCRIPTION

[0020] Embodiment 1

[0021] The multifunctional machine tool of this embodiment is as follows: Figures 1 to 6As shown, its basic structure is similar to that of the prior art: a battery pack is installed at the rear end of the housing 39, a motor is placed in the middle, and a transmission box 7 is installed at the front. The motor is connected to the output shaft through a swing transmission mechanism. The transmission box 7 is L-shaped, consisting of a vertical part supporting the output shaft 10 and the tool fast clamping device and a horizontal part for placing the motor and the transmission mechanism. The tubular vertical part supports the hollow output shaft 10 through the upper bearing 9 and the needle bearing 13 at the bottom. The swing transmission mechanism is composed of the output end of the motor rotor through the spherical bearing 27 at the front end of the eccentric shaft 33 and the fork of the fork 25 mounted on the output shaft 10.

[0022] The specific structure of the tool quick clamping device is as follows: it includes a rotatable vertical hollow output shaft 10 fixedly connected to the output shaft base 11 and a liftable pull rod 20 located in the output shaft 10. The output shaft base 11 is tightly mounted on the lower end of the output shaft 10, and its lower surface has a circumferential positioning protrusion D that matches the saw blade 24 as the tool to be clamped.

[0023] The lower end of the pull rod 20 has a support cone 20-1, and the middle part has a slide groove 20-2 that forms a vertical moving pair with the hinge pin 21. The hinge pin 21 is hingedly mounted on the upper part of the left chuck 22 and the right chuck 23 on both sides of the pull rod. The lower part of the left chuck 22 and the right chuck 23 is radially contracted so that the lower end extends out of the center hole of the output shaft base 11 and forms a lower limit step surface T in the middle. The inner side of the lower end of the left chuck 22 and the right chuck 23 matches the support cone 20-1, and the outer side has a neck that matches the installation hole of the saw blade 24 and a stopper Z.

[0024] The upper ends of the left chuck 22 and the right chuck 23 contact the small spring 18 sleeved on the pull rod 20 through the lower gasket 19, and the upper end of the small spring 18 contacts the pressing device that presses the pull rod 20 through the upper gasket 16. The upper gasket 16 is sleeved on the expanded shoulder of the pull rod 20 and is fixed to the pull rod 20 through the nut 14 and the spring washer 15 screwed on the upper end of the pull rod 20. The pressing device also contacts the upper end of the large spring 17 through the upper gasket 16, and the lower end of the large spring 17 is limited on the reduced diameter step of the output shaft 10.

[0025] Specifically, the pressing device includes a pressing block 6 which is sleeved on the flat section of the upper end of the pull rod 20 to form a mutual circumferential constraint. The upper end curved surface of the pressing block 6 and the lower end curved surface of the rotating seat 5 form an axial end face cam pair. The upper section outer circle of the rotating seat 5 is slidably matched with the upper through hole of the handle cover 4, and the middle diameter expansion ring is axially constrained to the lower end surface of the upper through hole of the handle cover 4. The handle cover 4 is tightly mounted on the upper part of the vertical part of the transmission box 7. In addition, the upper section outer circle of the rotating seat 5 is fixedly connected to the handle 2 with two set angular limit positions through the tightening screw 1, so that the rotating seat 5 can be driven to rotate by turning the handle 2, and then through the end face cam pair, the pressing block 6 can simultaneously axially press down the pull rod 20 and the large spring 17 and the small spring 18 through the reasonably set upper gasket 16.

[0026] The two angular limit positions of the handle 2 correspond to the upper limit and lower limit positions of the pressing device. When the handle 2 is turned to make the pressing device in the lower limit position through the end face cam pair, the force of the large spring 17 and the small spring 18 will be overcome at the same time to make the pull rod 20 and the left clamp 22 and the right clamp 23 pressed down and moved downward. Since the lower limit step surface T in the middle of the left clamp 22 and the right clamp 23 is first limited by the upper end surface of the output shaft base 11, the downward movement stroke of the pull rod 20 is greater than that of the left clamp and the right clamp, so that the left clamp 22 and the right clamp 23 are in a released state with the lower ends separated from the expansion cone 20-1 (see Figure 4 and Figure 5 ); During this process, the constraint of the slide groove 20-2 on the hinge pin 21 ensures the stable downward movement of the left clamp 22 and the right clamp 23 and avoids movement interference.

[0027] When the handle 2 is turned back to release the downward pressure of the end cam pair, the downward pressure device is in the upper limit position under the rebound and reset action of the large and small springs, and the pull rod 20 is lifted by the large spring 17 with a greater elastic coefficient than the small spring 18, so that the left clamp 22 and the right clamp 23 are in a tensioned state with the lower ends being stretched open by the expansion cone 20-1 (see Figure 2 and Figure 3 At this time, in fact, the small spring 18 still has a certain downward pressure on the left clamp 22 and the right clamp 23, which complements the upward pulling effect of the pull rod 20, enhances the fit and expansion with the expansion cone 20-1, and the stopper eaves Z ensures the reliable installation of the saw blade 24.

[0028] In addition to the above embodiments, the present invention may also have other implementations. For example, the pressing device may also adopt other structures such as a handle rotating around a horizontal axis. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A tool quick clamping device, comprising a rotatable vertical hollow output shaft fixedly connected to an output shaft base and a liftable pull rod located in the output shaft; characterized in that: The lower end of the pull rod has a support cone, and the middle part is provided with a slide groove which forms a vertical moving pair with a hinge pin, and the hinge pin is hingedly mounted on the upper part of the left chuck and the right chuck on both sides of the pull rod; the lower ends of the left chuck and the right chuck extend out of the central hole of the output shaft base, and the inner side of the lower end of the left chuck and the right chuck matches with the support cone, and the outer side matches with the mounting hole of the tool to be clamped; The pressing device has an upper limit position and a lower limit position; when in the lower limit position, the downward movement stroke of the pull rod is greater than that of the left and right clamps, so that the left and right clamps are in a loose state with their lower ends separated from the expansion cone; when in the upper limit position, the pull rod is elastically lifted so that the left and right clamps are in a tensioned state with their lower ends expanded by the expansion cone; The upper ends of the left and right chucks are in contact with the small spring sleeved on the pull rod, the upper end of the small spring is in contact with the pressing device that presses the pull rod, and the pressing device also is in contact with the upper end of the large spring, and the lower end of the large spring is limited to the output shaft; when in the upper limit position, the pull rod is lifted by the large spring whose elastic coefficient is greater than that of the small spring, so that the left and right chucks are in a tensioned state with their lower ends stretched open by the expansion cone.

2. The tool quick clamping device according to claim 1, characterized in that: The upper ends of the left clamp and the right clamp are in contact with the small spring sleeved on the pull rod through the lower gasket, and the upper end of the small spring is in contact with the pressing device through the upper gasket.

3. The tool quick clamping device according to claim 2, characterized in that: The upper gasket is sleeved on the expanded diameter shoulder of the pull rod and is fixedly connected to the pull rod by a fastener screwed on the upper end of the pull rod.

4. The tool quick clamping device according to claim 3, characterized in that: The pressing device contacts the upper end of the large spring through the upper gasket, and the lower end of the large spring is limited to the reduced diameter step of the output shaft.

5. The tool quick clamping device according to claim 4, characterized in that: The pressing device comprises a pressing block which is sleeved on the upper end of the pull rod to form a circumferential constraint on each other, and the upper end curved surface of the pressing block and the lower end curved surface of the rotating seat form an axial end face cam pair.

6. The tool quick clamping device according to claim 5, characterized in that: The upper outer circle of the rotating seat is slidably matched with the upper through hole of the rotating handle pressure cover, and the middle expansion ring is axially constrained to the lower end surface of the upper through hole of the rotating handle pressure cover; the rotating handle pressure cover is tightly installed on the upper part of the vertical part of the transmission box; the upper outer circle of the rotating seat is fixedly connected to the rotating handle by a fastener.

7. A multifunctional machine tool, comprising a housing with a motor mounted in the middle and a transmission box mounted in the front, wherein the motor is connected to an output shaft through a swing transmission mechanism, and the transmission box is composed of a vertical portion supporting the output shaft and a horizontal portion for mounting the motor and the transmission mechanism; characterized in that: The vertical portion is equipped with a tool quick clamping device as described in any one of claims 1 to 6.

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