Tool combining rod

#This invention relates to a tool combining rod, particularly to one able to fix the engaging head member of quickly and firmly, with the engaging head member possible to be lengthened and applicable to an automatic, screwdriver.

#Conventional tool combining rods are almost the same in structure. One conventional tool combining rod shown in FIGS. 1, 2 and 3 includes a rod member 1 and an engaging head member 2. The rod member 1 is bored at the front end with a combining hollow 10 have the same shape as that of the rod portion 20 of the engaging head member 2 so as to let them combined together closely. The combining hollow 10 is bored with one or two bead holes 12 in its wall 11 for receiving a bead 13, which is pressed by a sleeve 14, as shown in FIGS. 1 and 2. Or the combining hollow 10 may have its wall 11 bored with a C-shaped groove 12A for a C-shaped clasp 13A to be fitted therein, as shown in FIG. 3. Further, between the engage hole 12 and the engage bead 13 or between the C-shaped groove 12A and the C-shaped clasp 13A there must be a space and a little elasticity for the engage bead 13 and the C-shaped clasp 13A to move around in order to permit the engaging head member 2 to be pulled out for replacing and inserted in place with easiness.

#A fourth conventional tool combining rod, as shown in FIG. 4, includes a rod member 1 provided with a combining hollow 10 having a hole 15 in the rear side, and a C-shaped groove 12A in its wall for receiving a C-shaped clasp 16. Thus, in case the engaging head member 2 has to be pulled out or replaced, an auxiliary tool 3 has to be inserted in the hole 15 and pushed the bottom of the engaging head member 2 outward so as to take out or replace the engaging head member 2.

#This invention will be better understood by referring to the accompanying drawings, wherein:

#FIG. 1 is a cross-sectional view of a first kind of conventional tool combining rod:

#FIG. 2 is a cross-sectional view of a second kind of conventional tool combining rod:

#A preferred embodiment of a tool combining rod in the present invention, as shown in FIGS. 9, 10 and 12, includes a rod member 5, an engaging head member 6 and an engage member 7 as main components combined together.

#The rod member 5 has a front hollow 50 formed in a front end 5 and shaped as the shape of a rod portion 60 of the engaging head member 6 and having an annular groove 52 in the inner circumference 51 of the front hollow 50. The front hollow 50 has an annular tapered surface 53. A non-circular equiangular portion 55 formed in a rear part and the outer diameter of the non-circular equiangular portion 55 are larger than that of the outer surface 56 of the rod member 5.

#The engaging head member 6 has a rear rod portion 60 of a geometrical shape, the rear rod portion 60 with no grooves or recesses and fitting in the rod member 5, the front rod portion 61 has an engage portion 62 formed in a front end part, with the outer diameter of the rear rod portion 60 is larger than the front rod portion 61 to define a conical portion 63 there between.