A flat-bed sander

Abstract

The utility model relates to a flat plate sander and belongs to the technical field of electric tools. The product comprises a shell and a driving unit in the shell, the output end of the driving unit is sleeved with a mounting disc moving in an eccentric circular track plane through an eccentric shaft, the mounting disc is installed with a sand disc having a matching trisection positioning structure through a trisection limiting structure, and the bottom surface of the sand disc is a three-side structure corresponding to the trisection positioning structure. In this way, no matter how the sand disc is installed on the mounting disc in a circumferential position, it can ensure that three sharp protrusions are one forward, the other two are respectively left and right rear sides, and the three sharp protrusions can be arbitrarily exchanged in position, so it is very convenient, especially when the forward sharp protrusion is worn, another sharp protrusion can be converted, thereby prolonging the service life of the sand disc and saving the use cost.

Description

Technical Field

[0001] This utility model relates to a flat sander, and more particularly to an electric flat sander, belonging to the field of power tool technology. Background Technology

[0002] A typical structure of a flatbed (also known as a track-type) electric sander is disclosed in Chinese Patent Document CN202190000850.5, comprising a housing (14) and a drive unit (50) located within the housing (14). The drive unit (50) includes an electric motor (58) and a drive shaft (68). The electric motor (58) has a motor output shaft defining a rotation axis (62). The drive shaft (68) is coupled to rotate with the motor output shaft about the rotation axis (62). The drive shaft (68) has an eccentric portion (70) configured to move along a track about the rotation axis (62). A sanding pad (100) is coupled to the eccentric portion (70). A battery pack (26) is coupled to a handle (16) for powering the electric motor (58). The track-type sander (10) is easy for the user to grip.

[0003] The six types of sanding pads disclosed in the above technical solutions, when their sanding discs (116) are fixed to the brackets (66) that are loosely fitted on the output shaft (69) via the attachment (82), similar to other existing technologies, all rely on four or eight equally spaced positioning structures to achieve circumferential constraint of the sanding disc. Since the bottom surface of the sanding disc itself is not a regular polygon with the same number of positioning structures and has a pointed protrusion in a specific direction, it is not convenient to grasp the required positioning direction of the sanding disc and the bracket during assembly; furthermore, the sanding disc and the bracket need to use tools to tighten fasteners such as screws, or to tighten the buckles after insertion and ensure that the pointed protrusion faces forward, making it difficult to quickly change the sanding disc, which is also not convenient. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of the existing technology in terms of inconvenient positioning by proposing a flat sander that can properly install the sanding disc onto the bracket without controlling the positioning direction, thereby bringing convenience to the user.

[0005] To achieve the above objectives, the basic technical solution of the flat sander of this utility model is as follows: it includes a housing and a drive unit located in the housing. The output end of the drive unit is fitted with an eccentric shaft and a mounting plate that moves around the eccentric circular trajectory plane. The mounting plate is fitted with a sanding disc having a matching three-part positioning structure through a three-part limiting structure. The bottom surface of the sanding disc is a three-sided structure corresponding to the three-part positioning structure.

[0006] In this way, no matter what angle the sand disc is installed on the mounting plate, it can be ensured that one of the three protrusions faces forward, and the other two face left and right rear respectively. The three protrusions can then be rearranged at will, which is very convenient.

[0007] A further improvement of this utility model is that the sand disc contains a central metal insert, the upper part of which is plastically bonded to a three-sided reinforcing plate, and then bonded to a lower three-sided foamed component.

[0008] A further improvement of this utility model is that the lower surface of the mounting plate has a limiting recess in the center.

[0009] A further improvement of this utility model is that the limiting recess is formed by three equally divided limiting structures consisting of three spaced long sides and short sides of the recess.

[0010] A further improvement of this utility model is that the three-part positioning protrusion structure on the upper surface of the reinforcing plate is formed by three spaced long and short protrusions.

[0011] A further improvement of this utility model is that: the middle part of the recessed short side has a snap-fit ​​groove, and the corresponding position of the protruding short side has a snap-fit ​​protrusion.

[0012] A further improvement of this utility model is that the positioning protrusion structure has a dividing groove parallel to the short side of the protrusion.

[0013] A further improvement of this utility model is that: the inner circumference of the limiting recess has three circumferentially distributed spiral grooves, each spiral groove ending with a straight section, and the spiral direction is opposite to the working direction of the sand disc; the sand disc is formed by a metal insert to create a three-part positioning protrusion structure, and the upper end of the metal insert has three circumferentially distributed claws that are adapted to the spiral grooves respectively.

[0014] A further improvement of this utility model is that the lower end of the metal insert is a base with radial slots. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a structural schematic diagram of Embodiment 1 of the present invention.

[0017] Figure 2 yes Figure 1 A cross-sectional structural diagram.

[0018] Figure 3 yes Figure 1 A schematic diagram of the three-dimensional exploded structure.

[0019] Figure 4 yes Figure 1A three-dimensional exploded view of the sand disc installation structure.

[0020] Figure 5 This is a three-dimensional exploded view of the sand disc installation structure according to Embodiment 2 of this utility model.

[0021] Figure 6 yes Figure 5 A partially enlarged cross-sectional view of the sand disc installation in the embodiment.

[0022] Figure 7 This is a three-dimensional exploded view of the sand disc installation structure according to Embodiment 3 of this utility model.

[0023] Figure 8 yes Figure 6 A three-dimensional exploded structural diagram of the embodiment.

[0024] In the diagram: 1. Housing, 1-1. Left Housing, 1-2. Right Housing, 3. Motor, 6. Eccentric Shaft, 8. Bearing, 10. Bearing Chamber, 12. Mounting Plate, 12-1. Limiting Recess, 12-1-1. Long Side of Recess, 12-1-2. Short Side of Recess, 12-1-3. Snap-in Slot, 12-2. Spiral Snap-in Slot, 12-3. Straight Section, 14. Sand Disc, 14-1. Reinforcing Plate, 14-1-1. Long Side of Protrusion, 14-1-2. Short Side of Protrusion, 14-1-3. Snap-in Protrusion, 14-1-4. Splitting Slot, 14-2. Metal Insert, 14-2-1. Claw, 14-2-2. Insert, 14-3. Foaming Part, 15. Screw. Detailed Implementation Example 1

[0025] The basic structure of the flat sander in this embodiment is as follows: Figure 1 , 2 As shown in Figure 3, the housing 1, which is formed by the joining of the left housing 1-1 and the right housing 1-2, houses a drive unit mainly composed of a motor 3. The output end of this drive unit is connected to the eccentric shaft 6. The eccentric end of the eccentric shaft 6 is fitted with a mounting plate 12 that moves around the eccentric circular trajectory plane via a bearing 8 and a bearing housing 10. These are the same as in the prior art, see details. Figure 3 .

[0026] The structure of installation disk 12 is as follows: Figure 4As shown, the limiting recess 12-1 in the center of its lower surface has a three-part limiting structure formed by three spaced long recesses 12-1-1 and short recesses 12-1-2. The sand disc 14 contains a metal insert 14-2 in the middle. The upper part of the metal insert 14-2 is plastically bonded to the reinforcing plate 14-1 of the three-sided structure, and then bonded to the foam part 14-3 of the lower three-sided structure. The upper surface of the reinforcing plate 14-1 has a three-part positioning protrusion structure that matches the three-part limiting structure. The three spaced long protrusions 14-1-1 and short protrusions 14-1-2 of the positioning protrusion structure match the corresponding long recesses 12-1-1 and short recesses 12-1-2, respectively. The three-sided structure of the sand disc corresponds to the angular orientation of the three-part positioning structure.

[0027] When installing the sanding disc 14, simply insert its positioning protrusion into the limiting recess of the mounting disc 12 and then secure it with screws 15. Regardless of how the sanding disc is installed, one of the three protrusions will face forward, while the other two will face left and right rear respectively, making it very convenient. When the forward-facing protrusion wears out, the other protrusion can be easily replaced for continued use, thereby extending the service life of the sanding disc and saving on operating costs. Example 2

[0028] The basic structure of the flat sander in this embodiment is the same as that in Embodiment 1, with the following differences: Figure 5 , 6 As shown, the short side 12-1-2 of the limiting recess 12-1 on the lower surface of the mounting plate 12 has a snap-fit ​​groove 12-1-3 in the middle. The corresponding position of the short side 14-1-2 of the raised surface of the reinforcing plate 14-1 of the sand disc 14 has a snap-fit ​​protrusion 14-1-3. Furthermore, the positioning protrusion structure of the reinforcing plate 14-1 also has a split groove 14-1-4 parallel to the short side 14-1-2 of the raised surface. This allows the snap-fit ​​protrusion 14-1-3 to have good spring-back reset performance and prevents the snap-fit ​​protrusion 14-1-3 from being excessively deformed.

[0029] When installing the sand disc 14, simply insert its positioning protrusion into the limiting recess of the mounting disc 12, and the snap-fit ​​protrusion 14-1-3 will snap into the snap-fit ​​groove 12-1-3 in the middle of the short side 12-1-2 of the recess of the mounting disc 12 (see...). Figure 6 This allows for quick, tool-free installation. For replacement, simply pull the sand disc 14 outwards, causing the snap-fit ​​protrusion 14-1-3 to disengage from the snap-fit ​​groove 12-1-3, making it even more convenient. Therefore, this embodiment not only possesses the advantages of Embodiment 1 but also offers the outstanding and effective effect of convenient, tool-free sand disc replacement. Example 3

[0030] The basic structure of the flat sander in this embodiment is the same as that in Embodiment 1. The difference is that it features a different tool-free quick-change sanding disc structure, as detailed below. Figure 7 , 8As shown, the inner circumference of the limiting recess 12-1 on the lower surface of the mounting disc 12 has three circumferentially distributed spiral grooves 12-2, each spiral groove ending at a straight section 12-3, with the spiral direction opposite to the working spiral direction of the sand disc. The sand disc 14 is formed by a metal insert 14-2 forming a three-part positioning protrusion structure. The upper end of the metal insert 14-2 has three circumferentially distributed claws 14-2-1 that are adapted to the spiral grooves 12-2. Therefore, when installing the sand disc 14, simply screw the claws 14-2-1 of its positioning protrusion structure into the spiral grooves 12-2 of the limiting recess 12-1 of the mounting disc 12, and position them in the straight section 12-3, to achieve tool-free quick installation; the replacement is the reverse operation, which is also very convenient.

[0031] The lower end of the metal insert 14-2 is a recess 14-2-2 with radial slots, so it has better overall torsional resistance after plastic coating; and the spiral direction is opposite to the working direction of the sand disc, which can prevent the sand disc from loosening during operation.

[0032] In addition to the embodiments described above, this utility model may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by this utility model.

Claims

1. A flat sander, comprising a housing and a drive unit located within the housing, wherein the output end of the drive unit is fitted with a mounting plate that moves about an eccentric circular trajectory plane via an eccentric shaft, characterized in that: The mounting plate is equipped with a sand disc having a matching three-part positioning structure via a three-part limiting structure. The bottom surface of the sand disc is a three-sided structure corresponding to the three-part positioning structure.

2. The flat sander according to claim 1, characterized in that: The sand disc contains a central metal insert, the upper part of which is plastic-coated with a three-sided reinforcing plate, and then combined with a lower three-sided foam component.

3. The flat sander according to claim 2, characterized in that: The mounting plate has a limiting recess in the center of its lower surface.

4. The flat sander according to claim 3, characterized in that: The limiting recess is a three-part limiting structure formed by three spaced long sides and short sides of the recess.

5. The flat sander according to claim 4, characterized in that: The three-part positioning protrusion structure on the upper surface of the reinforcing plate is formed by three spaced long and short protrusions.

6. The flat sander according to claim 5, characterized in that: The recessed short side has a snap-fit ​​groove in the middle, and the protruding short side has a snap-fit ​​protrusion at the corresponding position.

7. The flat sander according to claim 6, characterized in that: The positioning protrusion structure has a segmented groove parallel to the short side of the protrusion.

8. The flat sander according to claim 3, characterized in that: The inner circumference of the limiting recess has three circumferentially distributed spiral grooves, each spiral groove ending with a straight section, and the spiral direction is opposite to the working direction of the sand disc; the sand disc is formed by a metal insert to create a three-part positioning protrusion structure, and the upper end of the metal insert has three circumferentially distributed claws that are adapted to the spiral grooves respectively.

9. The flat sander according to claim 8, characterized in that: The lower end of the metal insert is a base with radial slots.

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