1. Field of the Invention
The present invention relates to a fixed base router, more particularly to a fixed base router with accurate depth adjustment.
2. Background Art
A router is a power tool, typically used in woodworking, for applying a rotary cutting action to a workpiece. Particularly, a router is used for slotting, milling, finishing, edging and other rotary cutting operations. Routers that have a base for securing and maintaining the depth of the cutting tool, relative to the base, during the cutting operation are typically referred to as fixed base routers.
Fixed base routers are produced in a variety of different types and configurations. These fixed base routers have various adjustment mechanisms for varying and adjusting the height of a rotary cutting element relative to the base of the router. The cutting element is typically a router bit secured within a tool holder or a router collet and rotationally driven by a motor. Accordingly, the height of the cutting element relative to the base is typically adjusted by varying the height of the motor housing relative to the base.
Conventional fixed base routers typically include a motor housing having an external thread formed thereabout. Accordingly, either the fixed base includes a corresponding internal thread, or an adjusting ring rotationally affixed atop the fixed base has a corresponding internal thread. Thus, the motor housing is threadably engaged to the base or adjusting ring for attaching the motor housing to the fixed base and adjusting the height of the motor housing. Although these types of routers offer adjustment of the motor housing height and cutting element depth, the adjustability may be coarse due to the size of threads required about the motor housing. This coarse adjustment may not be as repeatable and accurate as a woodworker or craftsman may desire.
The industry has recognized a need for a router having an accurate cutting element depth adjustment. This need is evidenced by prior art fixed base routers having relatively fine adjustment or coarse and fine adjustment. However, these prior art fixed base routers having fine and/or coarse adjustments may require many parts thus increasing the manufacturing costs. Additionally, these adjustment provisions may be awkward or tedious to use, due to the positioning of the adjusting mechanism(s). Further, these adjustment mechanism(s) may lead to an increase in size of the fixed base or the motor housing. A simplified fixed base router is needed having a cutting element depth adjustment that is accurate, cost effective, compact and relatively easy to operate.
An object of the present invention is to provide a fixed base router including a base having a lower planar surface, an upper end, a central bore and a handle affixed thereto. An adjusting ring is rotatably affixed to the base upper end and is coaxial with the central bore. The adjusting ring has a series of gear teeth formed thereto defining a ring gear. A motor housing includes a motor secured therein for imparting rotational movement to a tool holder extending therefrom. The motor housing has an external thread formed thereabout. A pinion gear is journaled for rotation relative to the base and is engaged with the ring gear. The pinion gear is also coupled for rotation with a dial extending from the base. One of the adjusting ring and base has an internal thread formed therein engaged with the motor housing external thread. The other of the adjusting ring and base is adapted to prevent rotation of the motor housing relative thereto, such that rotation of the adjusting ring axially translates the motor housing relative to the base. One of the base and dial includes a scale and the other of the base and dial includes an indicator for indicating a relatively fine adjustment of the motor housing with respect to the base.