The present invention relates to a hand tool for grinding, and more particularly to a handheld belt sander.
A conventional belt sander has a handle and a rotating wheel driven by a motor. A support rod is disposed on a main body. A grinding belt encircles the support rod and the rotating wheel and is driven by the rotating wheel functioned by the motor to grind a surface of an object. However, the support rod extends forwardly from the main body in a straight direction, tightening the grinding belt to be very close to the support rod. Being stopped by the support rod, the grinding belt is not able to move to an appropriate position to fit an arc surface of the object. Then the arc shape of the ground surface may be damaged.
A conventional belt sander, such as that disclosed in TW Patent No. M519031, includes an adjustable rod pivotally connected with a support rod. A grinding belt is able to be pushed away from the support rod when the adjustable rod is pivotally moved relative to the support rod so as to form a space between the two rods and the grinding belt to be entered by the pressed grinding belt. Accordingly, an arc surface of an object may be ground well.
However, position of the adjustable rod must be firstly adjusted before grinding, which is not convenient to use because of time wasting. Besides, user must twist his wrist to make the grinding belt engage with the ground surface completely as a result of the adjustment to the adjustable rod executed at a terminal of the support rod. User's wrist may feel unwell after a long time use. Furthermore, the grinding belt, during work, is pressed to move laterally so that the high-speed grinding belt may separate from the roller and fly out to hurt the user.
The primary object of the present invention is to provide a handheld belt sander having a space formed between a grinding belt and a support rod to be entered by the pressed grinding belt. It is suitable to grind arc surfaces of objects and keeps a good hand posture to avoid damages. Additionally, the grinding belt can be blocked from moving laterally to separate from the rollers, and therefore user is protected.
In order to achieve the above object, a handheld belt sander is provided. The handheld belt sander includes a main body, a mount, a support member, a grinding belt and two side members. The main body has a motor connected with a rotating wheel. The mount is disposed at a fore end of the main body and is provided with a straight support rod extending along a first direction. A front roller is disposed on the support rod. The support member is disposed on the mount and extending along a second direction. The support member is provided with a rear roller having a wheel portion with an inner room, the inner room being enclosed with a dust-proof cover and accommodating two bearings separated by a spacer. A shaft fixed to the support member penetrates through the bearings, the spacer and the dust-proof cover. Each of the bearings, the spacer and the dust-proof cover has an annular axially protruding portion disposed at a side close to the shaft to abut each other so as to keep the bearings apart from the spacer and the dust-proof cover at a side far from the shaft. The grinding belt encircles the rotating wheel, the front roller and the rear roller. A space is formed between the support rod and a part of the grinding belt between the front roller and the rear roller so that the grinding belt moves into the space when pressed. The two side members are disposed on two sides of the support member. Each of the side members is provided with a column extending along the second direction. Each of the columns is rotatably connected with a side roller in alignment with the rear roller in the second direction. Each of the side rollers is located adjacent to the grinding belt and is separated from the grinding belt by a gap in order to block the grinding belt from separating from the rear roller when moving laterally. A position of a bottom portion of the rear roller is located between a top end and a bottom end of the side rollers.
Preferably, each of the side rollers is positioned on an end portion with a diameter greater than that of the column.
Preferably, each of the columns is fixed to the corresponding side member by threads.
Preferably, the mount has a notch portion with at least two positioning surfaces to be inserted by the support member, the support member abutting against the positioning surfaces for positioning.
Preferably, the first direction is perpendicular to the second direction.
Referring to
A notch 23, as shown in
As shown in
A grinding belt 6, as shown in
Referring to
Referring to
Moreover, in course of using the belt sander, user can hold the handle 13 in a natural wrist posture due to the support member 24 where the rear roller 4 is set being set on the mount 2, or the support member 24 is set close to the handle 13, so that user's wrist is not twisted to get hurt.
Owing to the improvement to the rear roller 4 for smooth rotating, the grinding belt 6 can rotate forward stably and not move laterally to separate from the rear roller 4. The grinding belt 6 may be pushed by the contact with the object to move laterally, but the moving grinding belt 6 will be blocked by the side rollers 53 from separating from the rear roller 4, avoiding user from damage.
Number | Date | Country | Kind |
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108215141 | Nov 2019 | TW | national |