Patent Publication Number: US-6666115-B2

Title: Magnetic driving tool having a telescopic pipe

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of my application Ser. No. 09/259,725 filed Mar. 1, 1999, now U.S. Pat. No. 6,326,626, which application is a continuation of my application Ser. No. 08/957,968 filed Oct. 21, 1997, now U.S. Pat. No. 5,878,637, which application is, in turn, a continuation-in-part of my application Ser. No. 08/643,026 filed May 2, 1996, abandoned. The disclosure of each of the aforesaid applications is hereby incorporated herein by reference thereto. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     (Not applicable) 
     BACKGROUND OF THE INVENTION 
     The invention relates to an extensible magnetic screwdriver. More particularly, the invention relates to an extensible screwdriver with a magnetic chuck. 
     The conventional screwdriver does not have any extensible rod. Thus the conventional screwdriver cannot reach a deep hole to screw or unscrew a bolt therein. If a bolt is unscrewed, the user cannot reach the deep hole to fetch the bolt. Further, the bit of any screwdriver may be fallen into the deep hole. The user cannot fetch the fallen bit with the conventional screwdriver. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an extensible screwdriver with a magnetic chuck in order to absorb a bit with the magnetic chuck. 
     Another object of the present invention is to provide an extensible screwdriver with an extensible inner pipe in order to reach a deep hole. 
     Another object of the present invention is to provide an extensible screwdriver with plurality of extensible inner pipes in order to reach a deep hole. 
     Accordingly, a screwdriver comprises a handle, a hollow outer sleeve, at least an inner pipe, and a bit. The rear end of the outer sleeve connects to the handle. The inner pipe is inserted in the interior of the outer sleeve via the front opening of the outer sleeve. A magnetic chuck is disposed at the front end of the inner pipe. The magnetic chuck is inserted in the rear portion of the bit. When a bolt is fallen down in a deep hole of an article, the magnetic chuck of the inner pipe reaches the bolt and absorbs the bolt on the front end of the magnetic chuck. It is an option to provide two inner pipes in the interior of the outer sleeve in order to extend the magnetic chuck. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective assembly view of a screwdriver of a preferred embodiment in accordance with the invention; 
     FIG. 2 is a perspective exploded view of FIG. 1; 
     FIG. 3 is a cross-sectional view of FIG. 1; and 
     FIG. 4 is a schematic view illustrating the operation of a screwdriver. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 to  3 , a screwdriver comprises a handle  11 , a hollow outer sleeve  10 , at least an extensible inner pipe  14 , and a bit  16 . The rear end of the outer sleeve  10  connects to the handle  11 . The inner pipe  14  is inserted in the interior  12  of the outer sleeve  10  via the front opening  13  of the outer sleeve  10 . A magnetic chuck  15  is disposed at the front end of the inner pipe  14 . The magnetic chuck  15  is inserted in the rear portion of the bit  16 . 
     Referring to FIG. 4, a bolt  92  is fallen down in a deep hole  91  of an article  90 . The magnetic chuck  15  of the inner pipe  14  reaches the bolt  92  and absorbs the bolt  92  on the front end of the magnetic chuck  15 . 
     It is an option to provide two inner pipes in the interior of the outer sleeve in order to extend the magnetic chuck. 
     The invention is not limited to the above embodiments but various modification thereof may be made. Further, various changes in form and detail may be made without departing from the scope of the invention.