Patent Publication Number: US-5897198-A

Title: Ratchet wrench with lamp circuit means

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a ratchet wrench, and more particularly to such a ratchet wrench which has a lamp circuit assembly installed in the ratchet unit thereof, and controlled to emit light by rotating a switch. 
     A variety of ratchet wrench have been disclosed, and have appeared on the market. These ratchet wrenches are functional, however, they are not practical for use in a dark place. When using a ratchet wrench in a drak place, a flash light is required to provide illumination. However, it is inconvenient to operate a ratchet wrench with one hand when the other hand holding a flash light. 
     It is one object of the present invention to provide a ratchet wrench which has a lamp circuit assembly installed in the ratchet unit thereof for providing illumination during the operation of the ratchet wrench. It is another object of the present invention to provide a ratchet wrench with a lamp circuit assembly which is controlled to emit light by rotating a switch is fastened to the ratchet unit by a screw joint. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of ratchet wrench according to the present invention. 
     FIG. 2 is a cutaway of the ratchet unit and exploded view of the lamp circuit assembly according to the present invention. 
     FIG. 3 is a sectional plain view showing the lamp circuit assembly installed in the ratchet unit according to the present invention. 
     FIG. 4 is a sectional elevation showing the lamp circuit assembly installed in the ratchet unit according to the present invention. 
     FIG. 5 is a sectional view taken along line 5--5 of FIG. 4. 
     FIG. 6 is a perspective view of the assembly of the ratchet unit and lamp circuit assembly according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. from 1 to 6, a ratchet wrench 1 is shown comprising a ratchet unit, which comprises a metal ratchet wheel 11, and a coupling shaft 111 integral with the ratchet wheel 11 at one side. A stepped longitudinal center through hole 112 is defined within the coupling shaft 111 and the ratchet wheel 11. An outer thread 1122 is provided within the greatest diameter of the stepped longitudinal center through hole 112. A locating groove 1121 is provided inside the longitudinal center through hole 112 on the middle. The stepped longitudinal center through hole 112 has different diameters arranged in proper order from the smallest toward the greatest in direction from the coupling shaft 111 toward the ratchet wheel 11. A lamp circuit assembly 2 is mounted in the stepped longitudinal center through hole 112. The lamp circuit assembly 2 is comprised of a lamp holder 21, a metal spring 22, a battery cell 23, a metal contact plate 24, and a switch 25. The lamp holder 21 is mounted in the stepped longitudinal center through hole 112 within the coupling shaft 111, having a contact plate 211 at one side. The battery cell 23 is mounted in the longitudinal center through hole 112, and partially engaged into the locating groove 1121. When the battery cell 23 is installed, the axial center of the battery cell 23 is not in alignment with the longitudinal central axis of the stepped longitudinal center through hole 112. The metal spring 22 is connected between the negative terminal of the battery cell 23 and the contact plate 211 of the lamp holder 21. The switch 25 has an outer thread 251 at one end threaded into the inner thread 1122 in the stepped longitudinal center through hole 112. The opposite end of the switch 25 extends out of the stepped longitudinal center through hole 112 for operation with the hand. The metal contact plate 24 is a horseshoe-like plate welded to one end of the switch 25. When the switch 25 is installed in the stepped longitudinal center through hole 112, the metal contact plate 24 is disposed adjacent to the positive terminal 231 of the battery cell 23. By means of rotating the switch 25, the circuit of the lamp circuit assembly 2 is turned on/off.