Patent Publication Number: US-6666114-B1

Title: Magnetic connecting tube for a screwdriver head

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a new and improved magnetic connecting tube for a screwdriver head, and more particularly, to an apparatus in which the repulsive force between two permanent magnets is utilized to drive out the screwdriver head. Meanwhile, the permanent magnet adjacent to the screwdriver head has the magnetic force to attract the screwdriver head such that the hexagonal head can be firmly attached and can&#39;t fall out of an engaging hole. 
     2. Description of the Prior Art 
     The screwing tools have been used for a long history. Their versions and structures are different according to the manufacturing factories and use surroundings. A conventional magnetic connecting tube, as illustrated in FIG. 6, for receiving hexagonal screwdriver head includes a main body  10 , a push element  11 , a spring element  12 , a fastening ring  13  and two engaging pearls  14 . The main body  10  has an engaging hole  15  at one end thereof for receiving a screwdriver head  16  and a compression spring  17  at the other end thereof. When the screwdriver head  16  is inserted into the engaging hole  15 , it presses against the compression spring  17  in compressed state. When the push element  11  is used to push the engaging balls  14  inwardly, the screwdriver head  16  will be driven out of the engaging hole  15  by means of the restoring force of the compression spring  17 . 
     Though the above-mentioned conventional structure can reach the expected effect of driving out the screwdriver head  16 , it also has the following application drawbacks: 
     1. The restoring force of the compression spring  17  has to meet certain requirements in order to smoothly drive out the screwdriver head  16 . Therefore, the screwdriver head  16  easily springs out of the engaging hole  15 . The user has to catch it with care. Otherwise, it is difficult for him to find the screwdriver head  16  again when he works in a disorderly small room or for highrise outdoor operation. Accordingly, the work must be seriously influenced. 
     2. The screwdriver head  16  has its own weight and structural strength. When it springs out or falls down to the ground and unfortunately hits persons around there, the consequence will be too terrible to imagine. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to eliminate the above-mentioned drawbacks and to provide a connecting tube for a screwdriver head in which the repulsive force between two permanent magnets is utilized to drive out the screwdriver head. Meanwhile, the permanent magnet adjacent to the screwdriver head has the magnetic force to attract the screwdriver head such that the hexagonal head can be firmly attached and can&#39;t fall out of an engaging hole. Therefore, the safety of persons around the operation site can be ensured. Moreover, a longer service life of the present invention can be maintained for thoroughly fulfilling the requirements of industries. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accomplishment of this and other objects of the invention will become apparent from the following description and its accompanying drawings of which: 
     FIG. 1 is an exploded view of a preferred embodiment of the present invention; 
     FIG. 2 is a sectional view of the preferred embodiment of FIG. 1; 
     FIG. 3 is a schematic drawing of the arrangement of two permanent magnets of the present invention; 
     FIG. 4 is a schematic drawing of the present invention, showing that the screwdriver hexagonal head is inserted; 
     FIG. 5 is a schematic drawing of the present invention, showing that the screwdriver hexagonal head is driven out; and 
     FIG. 6 is a sectional view of a prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     First of all, referring to FIGS. 1,  2  and  3 , a preferred embodiment of the present invention is shown. The magnetic connecting tube for a screwdriver head in accordance with the present invention includes a main body  20 , a push element  30 , a spring element  40 , a fastening ring  50 , a block member  60  and an engaging element  70 . The main body  20  is a hollow tube having an engaging hole  21  at one end thereof for receiving a hexagonal head  80  and having another hole for receiving a hexagonal bar  22 . The main body  20  includes a slot  23  near the engaging hole  21  for receiving the engaging element  70 . The slot  23  communicates with the engaging hole  21 . The main body  20  further includes an engaging groove  24  near the middle section thereof for receiving the fastening ring  50 . The push element  30  is inserted on the outer side of the main body  20  and includes a tapered groove  31  at the inner wall thereof. The tapered groove  31  is located in alignment with the slot  23 . An enlarged opening is formed at the rear end of the push element  30  for receiving the spring element  40 . The block member  60  is inserted into the rear end of the push element  30  for preventing the push element  30  from separating from the main body  20 . 
     The main body  20  includes under the engaging hole  21   a  through hole  25  in which two permanent magnets  26 ,  27  are so arranged that the repulsive poles face to each other (see FIG.  3 ). 
     As shown in FIGS. 4 and 5, when the hexagonal head  80  is inserted into the engaging hole  21 , it presses against the upper permanent magnet  26 . In order to drive out the hexagonal head  80  by means of the effect of the push element  30  and the engaging element  70 , the repulsive force between the permanent magnets  26 ,  27  is utilized to repel the hexagonal head  80  out of the engaging hole  21 . Meanwhile, the upper permanent magnet  26  has the magnetic force to attract the hexagonal head  80  such that the hexagonal head  80  can be firmly attached and can&#39;t fall out of the engaging hole  21  (see FIG.  5 ). 
     Many changes and modifications in the above-described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claim.