CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. ยง119 to CN 200820214749.6 filed Dec. 11, 2008, which is hereby incorporated by reference.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
TECHNICAL FIELD
The present invention relates to a router, and more particularly to a router with a cutting depth adjustment mechanism.
BACKGROUND OF THE INVENTION
In the prior art, a router with a cutting depth adjustment mechanism is known. The cutting depth is usually adjusted manually by loosening a clamping device located in the support foot of the router. However, this method of cutting depth adjustment is not precise enough to be acceptable. To achieve a precise cutting depth adjustment, Bosch's U.S. Pub. No. 20070065245A1 discloses a precise cutting depth adjustment mechanism that finely adjusts the cutting depth by rotating a motor housing relative to the support foot of the router. This method is not convenient for the operator and the adjustment mechanism disclosed is complicated.
SUMMARY OF THE INVENTION
To overcome the problems explained above, the present invention provides a router with a cutting depth adjustment mechanism that is convenient to operate and has a simple structure.
The present invention provides a router which has a motor housing for enclosing a motor, a support foot for receiving the motor housing, and an adjustment rod pivotally mounted to the support foot. An adjustment button is mounted to the adjustment rod, and part of the adjustment button extends out of the support foot. The adjustment rod includes a first engagement part and the motor housing includes a second engagement part in combination with the first engagement part. The adjustment rod can move between a first position where the first engagement part engages the second engagement part and a second position where the first engagement part disengages from the second engagement part.
An additional improvement of the present invention is that a switching button is mounted to the adjustment rod or the support foot. The switching button may include a cam surface or may be a screw. Further, a sphere is formed in one end of the adjustment rod away from the first engagement part, and a hole sized to receive the sphere is formed in the support foot. Also, one of the first engagement part and the second engagement part is an internal screw thread, and the other is an external screw thread.
As a result of the structure described above, a fine and coarse cutting depth adjustment may be done conveniently and easily.
BRIEF DESCRIPTION OF THE DRAWINGS
To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of a router according to a preferred embodiment of the present invention;
FIG. 2 is a partial cutaway view of a cutting depth adjustment mechanism of the router shown in FIG. 1 being in a coarse adjustment position;
FIG. 3 is a partial cutaway view of the cutting depth adjustment mechanism of the router shown in FIG. 1 being in a fine adjustment position;
FIG. 4 is an exploded view of the cutting depth adjustment mechanism of the router shown in FIG. 1;
FIG. 5 is an enlarged view of the cutting depth adjustment mechanism of the router shown in FIG. 2;
FIG. 6 shows a second embodiment of a switching button of the cutting depth adjustment mechanism of the present invention; and,
FIG. 7 shows a third embodiment of a switching button of the cutting depth adjustment mechanism of the present invention.
DETAILED DESCRIPTION
Referring to FIG. 1, a router of a preferred embodiment of the present invention comprises a motor housing 1 for enclosing a motor, a support foot 2 for receiving the motor housing 1 and a foot plate 3 mounted on the underside of the support foot 2. A longitudinal axis X of the motor (shown in FIG. 2) is perpendicular to the foot plate 3. A clamping device 4 mounted on the support foot 2 is used to tighten or loosen the motor housing 1 relative to the support foot 2. Because those skilled in this art are familiar with the clamping device 4, the clamping device 4 will not be described in detail here.
Now referring to FIGS. 2-5, a hole 18 is located in a lower part of the side wall of the support foot 2, and a through-hole 9 is formed in the bottom end of the support foot 2. An adjustment button 15 contains a square hole 14 formed in its center and a stepped surface 13. A switching button 19 contains a through-hole 16 in its center and a cam surface 17. The cam surface 17 engages with or disengages from the inner surface of the support foot 2 by rotating the adjustment button 15. The adjustment button 15 and the switching button 19 are mounted in the support foot 2 along the longitudinal axis X of the motor, and the centerlines of the square hole 14, the through-hole 16 and the through-hole 9 are in alignment. Part of the adjustment button 15 and the switching button 19 project out of the hole 18, so that they are accessible and may be conveniently operated by the operator. An adjustment rod 5 is mounted in the support foot 2, and a first screw thread 6 is formed on an upper part of the adjustment rod 5. A second screw thread 7 that meshes with the first screw thread 6 is formed on an outer surface of the motor housing 1. A sphere 8 and a stepped surface 11 are formed on a lower part of the adjustment rod 5. The adjustment rod 5 extends through the through-hole 9 in the bottom end of the support foot 2, the square hole 14 of the adjustment button 15 and the through-hole 16 of the switching button 19 so that the first screw thread 6 can engage with the second screw thread 7. The stepped surface 11 is in contact with the stepped surface 13 so that the sphere 8 is limited between the stepped surface 13 and the foot plate 3, and the movement of the adjustment rod 5 along its longitudinal direction is also limited. A tight fit is achieved between a part 12 of the adjustment rod 5 which has a square section and the square hole 14 of the adjustment button 15. The switching button 19 can rotate around the adjustment rod 5 relative to the adjustment button 15. The adjustment rod 5 may pivot on the sphere 8 for a certain range. In the present invention, the first screw thread 6 is an external screw thread and the second screw thread 7 is an internal screw thread. In another embodiment, the first screw thread 6 may be an internal screw thread and the second screw thread 7 may be an external screw thread. And in yet another embodiment, the second screw thread 7 is formed on a separate element mounted in the motor housing instead of being formed on the motor housing directly.
Referring to FIG. 3, the cutting depth adjustment mechanism of the router is in a fine adjustment position, and the switching button 19 is in a first position where the bigger radius part of the cam surface 17 rests against the inner surface of the support foot 2 and a force is applied to the adjustment rod 5 to make the first screw thread 6 engage the second screw thread 7. To do a fine adjustment of the cutting depth, the clamping device 4 is loosened, and then the adjustment button 15 is used to allow the adjustment rod 5 to rotate. As a result, the motor housing 1 is movable along the longitudinal axis X relative to the support foot 2 by means of the transmission between the first screw thread 6 and the second screw thread 7. The clamping device 4 is then tightened to fix the motor housing 1 on the support foot 2 when a desired cutting depth is adjusted.
The fine adjustment may be done precisely within a small adjustment range. To perform a larger cutting depth adjustment, a coarse adjustment is done first to bring the motor housing to a position around the desired cutting depth, then a fine adjustment is done to set the motor housing exactly in the desired cutting depth. Referring to FIG. 3, to do a coarse adjustment of the cutting depth, the clamping device is loosened, and then the switching button 19 is switched to a second position where the smaller radius part of the cam surface 17 is toward the inner surface of the support foot 2. Then, the adjustment button 15 is pressed downward slightly to allow the adjustment rod 5 to rotate around the sphere 8. In another embodiment, a magnet 20 is mounted on the inner surface of the support foot 2 close to the adjustment rod 5, and the adjustment rod 5 is attracted towards the inner surface of the support foot 2 by the magnet 20 and the adjustment rod 5 rotates around the sphere 8. As a result, the first screw thread 6 formed on an upper part of the adjustment rod 5 disengages from the second screw thread 7 formed on an outer surface of the motor housing 1, and the motor housing 1 can be pulled to a position around the desired cutting depth directly along the longitudinal axis X. After the larger movement is performed, when the switching button 19 is changed to the first position, a fine adjustment, as described above, is performed to set the motor housing to the exact cutting depth position, and the clamping device 4 is then tightened to fix the motor housing relative to the support foot 2.
FIG. 6 shows a second embodiment of the present invention, the switching button 19 is directly mounted to the support foot 2 using a rotating shaft 21. When the switching button 19 is rotated, the cam surface 17 presses against the adjustment rod 5 and the first screw thread 6 formed on an upper part of the adjustment rod 5 engages the second screw thread 7 formed on an outer surface of the motor housing 1. When the switching button 19 is then rotated in an opposite direction, the cam surface 17 disengages from the adjustment rod 5.
FIG. 7 shows a third embodiment of the present invention, the switching button 19 may be mounted to the support foot 2 using a screw. The switching button 19 may also be a screw rotatably mounted to the support foot 2. Part of the screw is inserted into the support foot 2 and is in contact with the adjustment rod 5. When the screw is rotated, the end face 22 of the screw presses against the adjustment rod 5 and the first screw thread 6 engages the second screw thread 7. When the screw is rotated in an opposite direction, the end face 22 of the screw disengages from the adjustment rod 5.
Persons skilled in the art can easily understand the first screw thread 6 formed in the adjustment rod 5 may be a first tooth part, and the second screw thread 7 formed in the outer surface of the motor housing 1 may be a second tooth part.
The above described preferred embodiments are intended to illuminate the principle of the present invention, but not to limit its scope. It can be easily understood for those skilled in the art that many other modifications and variations of these preferred embodiments will be apparent and may be made without departing from the spirit and the scope of the invention as defined in the following claims.
Patent Application
20100150679
