Ratchet wrench

A ratchet wrench includes a body, a ratchet wheel, a control unit, and a rotary knob. The body has an end forming a ratchet wheel bore and a receiving hole, which respectively and rotatably receive the ratchet wheel and the rotary knob therein. A channel is defined in the body between the ratchet wheel bore and the receiving hole for receiving therein the control unit. The control unit includes two detent blocks and a spring. The detent blocks are selectively engageable with teeth formed in the ratchet wheel. The rotary knob retains a control bar and a positioning ball. The receiving hole has an inner circumferential wall in which two positioning notches are defined. The control bar is operated to move the detent blocks to desired positions and the positioning ball is biased by a spring into selective engagement with the positioning notches for proper positioning of the detent blocks.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to a ratchet wrench, and particularly to a ratchet wrench that contains simplified parts but is effectively in change of rotational direction.

DESCRIPTION OF THE PRIOR ART

A conventional ratchet wrench, designated at1, is illustrated inFIG. 1of the attached drawings, and generally comprises a body11, a ratchet wheel mounted inside an end of the body11, a detent block13, and a switching member14. The detent block13is engageable with the ratchet wheel12, and the switching member14is in operative coupling with the detent block13. An end121of the ratchet wheel12extends outside the end of the body11to rotatably couple to a control knob16through a retainer15. The control knob16is in operative coupling with the switching member14for controlling the switching member14to rotate the detent block13so as to effect direction change of the rotation of the ratchet wrench1.

The above described construction of the conventional ratchet wrench1is effective in realizing direction change, but is comprised of numerous parts, which needs elaborate and complicated handling and machining, making the expense for manufacturing and assembling very high and thus lowering market competitivity. In addition, since the wrench is composed numerous parts, the wrench becomes bulky and heavy, making the use thereof difficult and inconvenient.

Further, since the control knob16is rotatably coupled to an end121of the ratchet wheel12, to prevent the control knob16from being undesired moved due to the rotation of the ratchet wheel12, a sophisticated retention device17must be arranged to ensure proper positioning of the control knob16, and further, the control knob16must be elaborately structured in order to maintain good rotatable coupling with the ratchet wheel12. This certainly increases the manufacturing expense. Further, since the working environments for the ratchet wrench may be unorganized and dirty, often leading to dirt or contaminants entering and hiding in the coupling between the control knob16and the ratchet wheel12. This may deteriorate the coupling engagement between the control knob16and the ratchet wheel12and leads to improper operation of direction change in the use of the wrench. In addition, the conventional ratchet wrench1is not equipped with means for reciprocation of the detent block13and teeth formed on the detent block13may easily get jammed with teeth of the ratchet wheel12, leading to incapability of rotation in reversed direction.

In view of the above drawbacks of the conventional ratchet wrench1, the present invention aims to provide a ratchet wrench featuring simplification of parts but still maintaining proper operability of change of rotational direction.

SUMMARY OF THE INVENTION

The primary technical solution of the present invention is to provide a ratchet wrench, which comprises at least a body, a ratchet wheel, a control unit, and a rotary knob. The body has an end forming a ratchet wheel bore and a receiving hole, which respectively and rotatably receive the ratchet wheel and the rotary knob therein. A channel is defined in the body between the ratchet wheel bore and the receiving hole for receiving therein the control unit. The control unit includes two detent blocks and a spring. The detent blocks are biased by the spring to be alternately engageable with teeth formed in the ratchet wheel. The rotary knob retains a control bar and a positioning ball. The receiving hole has an inner circumferential wall in which two positioning notches are defined. The control bar is operated to selectively move the detent blocks to desired positions and the positioning ball is biased by a spring into selective engagement with a corresponding one of the positioning notches for proper positioning of the detent blocks. As such, the detent blocks can be properly positioned and convenience of use can be realized.

The secondary technical solution of the present invention is to provide a ratchet wrench, which comprises at least a body, a ratchet wheel, a control unit, and a rotary knob. The body has an end forming a ratchet wheel bore and a receiving hole, which respectively and rotatably receive the ratchet wheel and the rotary knob therein. The rotary knob forms rough knurled pattern by which an increased frictional force is provided for a user's operation of rotation and thus convenience of rotation of the rotary knob is realized.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be explained with reference to the drawings.

Initial reference is made toFIGS. 2 and 3. The present invention provides a ratchet wrench2, which comprises at least a body21, a ratchet wheel22, a control unit23, and a rotary knob24.

The body21has an end211forming a ratchet wheel bore212and a receiving hole213, both extending therethrough. Bottom parts of the ratchet wheel bore212and the receiving hole213each form an expanded opening2121,2131. A channel214is defined in the body21between the ratchet wheel bore212and the receiving hole213. The receiving hole213has a circunmferential inner wall forming two positioning notches2132.

The ratchet wheel22is received in the ratchet wheel bore212of the body21. The ratchet wheel22has an upper portion forming circumferentially teeth221and a lower portion forming a working end222. The working end222comprises a steel ball223movably embedded therein. The ratchet wheel22forms, in a central portion thereof, a through hole224in which a push button225and a spring226are received. The ratchet wheel22is provided with a positioner ring227at the lower portion thereof and the positioner ring227is tightly fit into the expanded opening2121of the body21to position and retain the ratchet wheel22in the ratchet wheel bore212.

The control unit23comprises two detent blocks231,232and a spring233. Each detent block231,232forms at one end thereof a toothed face2311,2321engageable with the teeth221of the ratchet wheel22. Each detent block231,232forms a peg2312,2322at an opposite end thereof. A receiving space2313,2323is formed between the toothed face2311,2321and the peg2312,2322of each detent block231,232. The detent blocks231,232are structured and arranged to mutually fit to and mate each other and the spring233is received in the receiving spaces2313,2323and is thus set between the two detent blocks231,232. The spring233comprises a corrugated plate formed in a fan shape. The spring233provides an outward-directing resiliency due to the corrugated configuration thereof in order to maintain an outward expanded condition of the detent blocks231,232. Further, the spring233comprises a flat section2331at a middle portion thereof and the flat section2331corresponds in position to the channel214formed in the end211of the body21.

The rotary knob24has an upper portion forming an expanded, diameter-increased head241having a circumferential surface that forms knurling2411. A stem242extends downward below the head241. The stem242forms two deep holes2421,2422. The deep hole2421receives therein a control bar243, which is of such a length that is partially exposed outside the stem242after being fully inserted into the hole2421. The hole2422receives therein a spring244and a positioning ball245, which corresponds in position to the positioning notches2132of the body21. The rotary knob24is provided with a positioner ring246at a lower portion thereof and the positioner ring246is tightly fit into the expanded opening2131of the body21in order to position and retain the rotary knob24in the receiving hole213of the body21.

Referring toFIG. 4, to practice the present invention, the spring244and the positioning ball245of the rotary knob24are positioned into the deep hole2422of the stem242. The stem242of the rotary knob24is then fit into the receiving hole213of the body21. The control bar243is moved through the channel214to fit into the deep hole2421of the stem242of the rotary knob24. Thereafter, the positioner ring246is tightly fit into the expanded opening2131of the receiving hole213. Afterwards, the two detent blocks231,232of the control unit23are fit to each other in a vertical direction and the spring233is set in the receiving spaces2313,2323of the detent blocks231,232, which are then all put into the channel214of the body21, whereby the control bar243is located between the pegs2311of the two detent blocks231and the flat section2331of the spring233. The flat section2331of the spring233provides a space for accommodation of the control bar243in order to prevent interference between the control bar243and the corrugation of the spring233. Finally, the push button225and the spring226are put into the through hole224of the ratchet wheel22and the ratchet wheel22is put into and retained in the ratchet wheel bore212of the body21by tightly fitting the positioner ring227into the expanded opening2121of the ratchet wheel bore212. This completes the assembling of the ratchet wrench.

Referring toFIG. 5, to operate the present invention, the head241of the rotary knob24is rotated to make the control bar243driving the peg2312of the detent block231for inducing movement of the detent block231, so that the toothed face2311is caused to disengage from the teeth221of the ratchet wheel22. In addition, the spring233also applies a force to the other detent block232to make the toothed face2321of the detent block232engaging the teeth221of the ratchet wheel22. The control bar243of the rotary knob24is properly set in position by the spring244biasing the positioning ball245into engagement with the corresponding positioning notch2132, which also makes the rotary knob24properly set in position. Under this condition, the body21of the ratchet wrench2can make rotation in a first direction, such as clockwise direction.

On the other hand, as shown inFIG. 6, to change the direction of rotation of the ratchet wheel22, the rotary knob24is rotated to the opposite direction, making the control bar243driving the peg2322of the detent block232for inducing movement of the detent block232, so that the toothed face2321disengages from the teeth221of the ratchet wheel22. The spring233also applies a force, in an opposite manner, to the detent block231to make the toothed face2311of the detent block231engaging the teeth221of the ratchet wheel22. The control bar243of the rotary knob24is properly set in position by the spring244biasing the positioning ball245into engagement with the corresponding positioning notch2132, which also makes the rotary knob24properly set in position. Under this condition, the body21of the ratchet wrench2can make rotation in an opposite second direction, such as counterclockwise direction.

The effectiveness of the present invention is that by providing a channel214between the ratchet wheel bore212and the receiving hole213for completely accommodating therein the control unit23, contaminants and other dirt are prevented from entering and being hiding in the control unit23to resist the operation of the detent blocks231,232and the ratchet wheel22. Further, by providing the control bar243and the positioning ball245in the rotary knob24and forming two positioning notches2132in an inner circumferential wall of the receiving hole213, after the detent blocks231,232are moved by the control bar243, the detent blocks231,232can be properly set in position by the spring244biasing the positioning ball245into engagement with the corresponding positioning notch2132, so as to realize convenience of operation and use. Further, the head241of the rotary knob24is provided on the circumferential surface thereof, with knurling2411, which provides an effective frictional force when being rotated by a user so as to realize easy rotation of the rotary knob24.