Drill lifting and lowering device for electric drill
This application is a continuation, of application Ser. No. 206,074, filed Nov. 12, 1980, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a drill lifting and lowering device of electric drills. 
     In use of conventional electric drills of portable type, the drills are pressed against the drilling object solely by manual force. Therefore, the working place and position of the operator are impractically limited which in turn imposes quite a heavy fatigue of the operator. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the invention to elminiate the above-described problem of the prior art, by providing a drill lifting and lowering device for electric drills, comprising means for supporting a drill shaft for free up and downward movement, and a lifting and lowering lever associated with the drill shaft, so that the drill can be lifted and lowered easily by manipulation of the lever. 
     Another object of the invention is to provide a drill lifting and lowering device for electric drills, wherein a bracket supporting the lifting and lowering lever carries also a device for holding the drilling object, so that the lifting and lowering lever can be manipulated with the drill body held by the drilling object to ensure a safe and efficient drilling operation. 
     To these ends, according to the invention, there is provided a drill lifting and lowering device for electric drills, characterized by comprising: an attaching guide fixed to a bearing portion of the drill body; a drill shaft adapted to be rotated in accordance with the rotation of the drill body and received by the attaching guide for free up and downward movement; a bracket provided at the outside of the attaching guide and provided with a drilling object holding device; a lifting and lowering lever pivotally supported by the bracket; and a guide collar loosely fitted to the drill shaft and provided with an engaging groove engaged by the end of the lifting and lowering lever. 
     The above and other objects, as well as advantageous features of the invention will become clear from the following description of the preferred embodiment taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of an embodiment of the invention; and 
     FIG. 2 is a perspective view of an essential part of the embodiment shown in FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, a reference numeral 1 designates a drill device which is an ordinary electric drill. A reference numeral 2 denotes a bearing portion of the drill device 1, adapted to rotatably support a rotary shaft 3. Usually, a drill chuck 4 is directly attached to the bearing portion 2. A reference numeral 5 designates an attaching guide secured to the bearing portion 2. This guide 5 is a cylindrical guiding member adapted for supporting a drill shaft 6 for free up and downward movement. If the guide 5 is secured detachably by means of screws, it can be detachably replaced with the drill chuck 4 so that the conventional electric drill can be used directly. 
     A sleeve 7 is rotatably received by the attaching guide 5 and adapted to be disengageably engaged at its one end by the rotary shaft 3 so as to be rotated together with the latter. The drill shaft 6 is slidably mounted in the guide bore of the sleeve 7. Namely, the sleeve 7 has a pin 8 which is received by an elongated hole 9 formed in the drill shaft. The drill chuck 4 is fitted to and supported by the end of the drill shaft 6. A reference numeral 10 designates a bracket which is rotatably supported such that its position in relation to the attaching guide 5 may be changed. A reference numeral 11 denotes a fixing screw. 
     A drilling object holding device denoted by a numeral 12 has a supporting lever 13 by means of which it is attached to the bracke 10, and is extended to the position to which the drill 16 is lowered. The position of the drilling object holding device 12 is adjustable in the vertical direction by means of an elongated hole 14 formed in the supporting lever 13 and a screw 15 provided in the bracket 10. 
     In case that the drilling object holding device 12 is formed as a supporting plate as shown in FIG. 1, the drilling object (a) is contacted at its rear side by the supporting plate, so that the drilling is made effectively with the drilling object (b) clamped between the supporting plate as the drilling object holding device 12 and the drill 16. The drilling device, therefore, can effectively be used for the drilling in already-constructed steel structures. 
     FIG. 2 shows another form of the drilling object supporting device 12. Namely, in this case, the drilling object supporting device 12 is composed of a permanent magnet adapted to attract and hold the drilling object. Since the permanent magnet attaches to the surface of the drilling object, the drilling object holding device incorporating the permanent magnet is suitable for use in the drilling in a drilling object having a flat surface. Furthermore, although not illustrated, the drilling object holding device 12 can be constituted by screws. 
     A reference numeral 17 designates a lifting and lowering lever having a support shaft 18 carried by the bracket 10. A guide collar 19 loosely fitted to the drill shaft 6 is provided in its periphery with an engaging groove 20 which engages the end 21 of the lifting and lowering lever 17. 
     In use of the device of the invention having the described construction, the drill shaft 6 and, accordingly, the drill chuck 4 and the drill 16, are lowered to drill a bore in the drilling object (a), as the lifting and lowering lever 17 is operated while supporting the drilling object (a) by the drilling object holding device 12. 
     Thus, in the device of the invention, the drill 16 of the electric is lowered by a lever action of the lifting and lowering lever 17, so that the drilling is made quite easily. 
     In addition, since the drilling object holding device 12 is supported by the drill device 1, the latter can stably be held perpendicularly to the drilling object (a), so that the work is facilitated very much and the bore is drilled correctly perpendicularly. 
     Furthermore, since the drill 16 is freely moved up and down by the lifting and lowering lever 17, while the drill device 1 is carried by the drilling object supporting device 12, it becomes possible to conduct the drilling work at such restricted, high or low places where the drilling work could never be made efficiently with the conventional drills. 
     Finally, the drill lifting and lowering device of the invention, having a simple construction, can be easily attached to existing electric drills.