PORTABLE POWER TOOL

Abstract: A portable power tool comprises a power drill 101 with a pair of handles 102, 102′, each having an aperture 103, 103′. A mounting member has an endpiece 107 with a shoulder rest 119. The beam of the mounting member may be clamped into a groove 106 on the top of the power drill to provide the drill with a shoulder rest, or it may be assembled in a second position with the beam 104 passing through the apertures 103, 103′. Hinged legs 120 on the end piece 107 are folded outwards, and the tool when assembled in this manner provides a vertical bench drill.

Description: The invention relates to portable power tools and in particular to electric drills. Such drills normally comprise a body provided with handles, and housing an electric motor together with gearing through which the motor drives a chuck. Such a tool will be referred to herein as a power drill, notwithstanding that other tools, for example grinding wheels, ring cutters, reamers etc, may be fitted into the chuck in place of the drill bit. It is known to provide a bench stand to which such a power drill may be fitted so that it may be used as a bench drill, in addition to its normal use as a hand held tool. The present invention, which is defined in the claims appended hereto, aims at providing a compact and convenient tool capable of alternative uses in this manner. An example of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an exploded view showing the essential parts of a tool according to the invention; Figure 2 shows the tool assembled for hand use and Figure 3 shows the tool assembled as a bench drill. Referring first to figure 1, the tool comprises a power drill main body 101 provided with a handle 102 with the usual trigger type on/off switch (not visible in the drawing). The body also carries a second projection 102′, which may be shaped with a grip to form a second handle, lying in the same plane as the handle 102. A pair of apertures 103, 103′ are formed in these handles through which the beam 104 of a mounting member about to be described, may be passed parallel to the axis of the drill chuck and on which the drill forms a sliding fit. The mounting member comprises a beam 104 mounted on an endpiece 107. The beam as has been mentioned, is a sliding fit in the apertures 103, 103′ and may be formed with grooves or ridges, in which case the apertures may be provided with matching projections or grooves. The beam carries a sliding ring 109 which may be locked by a clamping screw 110 and which carries a pivoted collar 113. The end piece 107 on the side remote from the beam 104 carries a padded shoulder rest 119 shaped like the end of a rifle-butt. The top of the drill body, that is to say the side remote from the handles 102, 102′, is formed with a channel 106 into which the end of the beam 104 can slide and in which it can be clamped by a pair of set screws 121, 121′. Grooves or ridges on the beam 104 engage corresponding ridges or grooves in the channel 106. The drill body also has a side handle, comprising an internally screw boss 112 into which a knob 117 can be screwed. The boss 112 has a hole through it through which a rod 115 can be slid and clamped by tightening the knob 117. The rod 115 has a ball at one end and is screw-threaded at the other; the boss 112 also has an oblique hole 114 of elongated section. The purpose of these details will be explained below. Refer now to Fig. 2, which shows one position of use of the tool of invention. In this position the beam 104 has been inserted into the slot 106 and clamped in position by tightening the screws 121, 121′. The screw 110 has been tightened, so that the clamping ring 109 merely retains the spring 111, which is inoperative in this particular configuration, on the beam. The device is now used as a drill, the padded shoulder piece 119 being rested against the operator's shoulder to enable additional pressure to be applied comfortably to the drill, and the rod 115, clamped by tightening the knob 117, serves as a stop or depth gauge to control the depth of drilling. Referring now again to Figure 1, the power tool of the invention contains further features which enable it to be used as a vertical bench drill. The end piece 107 carries a pair of pivoted legs, one of which, 102, is visible in the figure, and each of these carries a levelling screw 121 at its extremity. The shoulder piece 119 also carries a stud 122 which, in the vertical drilling assembly position of the tool of the invention, acts as a foot. Refer now to Figure 3, which shows the tool of the invention assembled as a vertical bench drill. The pivoted legs 120 have been swung outwards, so that the mounting member is resting on the stud 122 (not shown in figure 3) and on the two leveling screws 121. The spring 111 and the clamping ring 109 have been interchanged in position and placed on the beam 104, which is now upright, and the portable drill body rests on the spring 111 with the beam 104 passing through the holes 103, 103′. The rod 115 passes through the elongated holes 114 in the boss 112 which allow it some freedom of rotation, and the threaded end is screwed into the pivoted collar 113. As will be seen, the arrangement now forms a vertical bench drill in which the endpiece 107 forms the drill table and the drill is movable up and down against the balancing force of the spring 111 by moving the rod 115 to control the vertical movement, the ball now acting as a handle.

Claims: 1. A portable power tool (101) comprising a power drill and a mounting member for the drill comprising a beam (104) and an endpiece (107) attached to one end of the beam, the mounting member being attachable to the drill in a first, fixed, position in which the end piece (107) provides a shoulder rest (119) for applying drilling pressure, and in a second position in which the drill is slidable along the beam (104) with its axis parallel to the beam and in which the endpiece (107) forms a base for maintaining the beam in an upright position for vertical drilling. 2. A portable power tool according to claim 1 in which handle (102) of the power drill is provided with an aperture (103) and the drill carries a projecting portion (102′) formed with a corresponding aperture (103′), the apertures each being shaped to admit the beam (104) of the mounting member when the tool is assembled in the second position. 3. A portable power tool according to claim 1 or claim 2 in which the endpiece (107) of the mounting member is provided with a stud (122) and a pair of folding feet (120) which may be extended so as to provide a three-point support for the tool when assembled in the second position. 4. A portable power tool according to any preceding claim in which the endpiece (107) is provided with a padded member (119) to form the shoulder rest. 5. A portable power tool according to any preceding claim in which the power drill is provided with a boss (112) on one side, the boss having a first opening through which a rod (115) may be passed and clamped parallel to the drill axis to serve as a depth gauge when the tool is used in its first position, and a second opening (114) through which the rod (115) may be passed with freedom of rotational movement so as to serve as a operating handle for the vertical movement of the drill in its second position.

Inventors: YANG, TAI-HER
Applicants: YANG, TAI-HER
Application year: 1988
Main classification: B23B45
IPC codes: B25F5, B25H1, B23B45