Patent Application
20080008551
FIG. 1 is a front view of a known router.
FIG. 2 is a perspective view of a router embodying the present invention.
Referring to FIG. 2, in which parts common to the router of FIG. 1 are denoted by like reference numerals but increased by 100, a router 102 embodying the present invention includes a motor housing 104 containing a motor (not shown) for driving a collet 106 to which a cutting tool (not shown) is mounted in use for engaging a workpiece (not shown) through an aperture 108 in a base 110 which rests on the workpiece.
The motor housing 104 is mounted to a router frame 105 having a first support member 112 mounted to a lower part of the motor housing 104 and a second support member 140 mounted to an upper part of the motor housing 104. The support members 112, 140 are mounted to a pair of hollow cylinders 107, 109, and the lower support member 112 is provided with a pair of handles 114, 116, one of which is provided with a switch (not shown) for actuating the motor in the motor housing 104.
The router frame 105 is slidably mounted relative to the base 110 by means of support columns 118, 120 which are mounted to the base 110 and are slidably mounted within the hollow cylinders 107, 109 respectively of the router frame 105 so that the router frame 105 can be pushed downwardly relative to the base 110 against the action of a spring (not shown) provided on at least one of the support columns 118, 120. In particular, one of the support columns 118, 120 is slidably mounted within the corresponding hollow cylinder 107, 109, and a helical tension spring (not shown) is either connected directly between the support column 118, 120 and corresponding hollow cylinder 107, 109, or is connected, at its lower end, to a retaining bush fastened to a guide tube which surrounds the support column 118, 120 and is arranged between the support column 118, 120 and the corresponding hollow cylinder 107, 109, and at its upper end to a holding ring secured to the upper end of the support column 118, 120.
The support column 118 is hollow and connects a channel 142 communicating with aperture 108 in base 110 with an outlet 144 which can be connected to a suitable suction source such as a vacuum cleaner to enable dust produced by the cutting tool to be removed to prevent it from obscuring visibility of the tool.
A height adjustment abutment member 126 is slidably mounted to a bracket 146 on lower support member 112 and can be fixed in position by means of a thumb screw 128. A rack and pinion mechanism (not shown) enables fine adjustment of the axial position of the abutment member 126 relative to the bracket 146 by means of a further thumbscrew 148. By suitable adjustment of the axial position of abutment member 126, the depth of cutting of the cutting tool in collet 106 is adjusted and is set by the position with which the lower end of the abutment member 126 comes into abutment with either the base 110 or one or more suitable further abutment members (not shown) mounted to the base 110.
The router shown in FIG. 2 has the advantage that because the motor housing 104 is restrained by spaced apart support members 112, 140 adjacent its upper and lower ends, vibrations generated by the motor in the housing 104 are more effectively absorbed, and mis-alignment of the motor housing 104 relative to the router frame 105 is more difficult. Also, because the motor housing 104 is mounted to the support columns 118, 120 at locations further apart than in the case of the router of FIG. 1 (at least when the motor housing 104 is in its lowered position relative to the base 110 during cutting by the tool), angular movement of the router frame 105 relative to the base 110 is minimised. As a result, lateral variation in the position of the cutting tool mounted to collet 106 is minimised, and the accuracy of cutting of the tool is thereby improved.
It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only, and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims. For example, the support members 112, 140 may be formed integrally with or separable from the hollow cylinders 107, 109. These and other implementations are within the scope of the following claims.
