Method for making wrenches

Description

FIELD OF THE INVENTION

The present invention relates to a method with less steps for making a wrench of less weight.

BACKGROUND OF THE INVENTION

A conventional method for making a wrench is shown in FIGS. 1 and 2 and generally includes the following steps:

sep 1: preparing material: preparing material which is a cylindrical alloy stick “A”;

step 2: forging: forging the stick “A” in a mold;

step 3: basic form: cutting the stick “A” into a basic form 1 including a head 10 and a handle 11;

step 4: surface machining: machining the two opposite surfaces 101, 102 of the head 10 of the basic form 1;

step 5: drilling: drilling a hole 103 in the head 10 and making a recess 104 defined in the surface 101 of the head;

step 6: contouring: making the basic form 1 to include the head 10, the handle 11 and a grip portion 12;

step 7: prototype 1′;

step 8: heat treatment: proceeding heat treatment (annealing) to the prototype 1′ under at least 1000° C.;

step 9: surface grinding: grinding surfaces of the prototype 1′;

step 10: final surface treatment: proceeding final surface treatment by way of sand blowing or vibration;

step 11: electro-plating: electro-plating a layer of anti-rusting material to the prototype 1′; and

step 12: obtaining a product.

However, the head 10 and the handle 11 are made by alloy which is heavy and expensive. Besides, most of the alloy is electrically conductive so that the wrench is limited to be used in some work sites. The sizes of the head 10 and the handle are different so that, during the step of forging, a large space or tolerance has to be maintained and which makes the material needed increases.

The present invention intends to provide a method for making a wrench wherein the number of steps is reduced and the weight of the wrench is also less than the conventional wrench made by the conventional method.

SUMMARY OF THE INVENTION

The present invention relates to a method for making wrench and the method comprises the following steps:

sep 1: preparing material: preparing raw material which is a cylindrical alloy stick;

step 2: forging: forging the stick in a mold;

step 3: basic form: cutting the stick into a basic form including a head and a handle;

step 4: surface machining: machining two opposite surfaces of the head of the basic form;

step 5: drilling: drilling a hole in the head and making a recess defined in the surface of the head;

step 6: prototype;

step 7: heat treatment: proceeding heat treatment (annealing) to the prototype;

step 8: plastic part installation: putting the prototype in a mold and plastic material being introduced to cover the head, the handle and the grip portion, and

step 9: obtaining a product.

The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows steps of a conventional method for making a wrench;

FIG. 2 shows the wrench in different steps;

FIG. 3 shows steps of the method for making a wrench of the present invention;

FIG. 4 shows the wrench in different steps of the method for making a wrench of the present invention, and

FIG. 5 shows steps of another method for making a wrench of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3 and 4, the method for making a wrench of the present invention comprises the following steps:

sep 1: preparing material: preparing raw material which is a cylindrical alloy stick “A”;

step 2: forging: forging the stick “A” in a mold which is not shown;

step 3: basic form: cutting the stick “A” into a basic form 3 including a head 30 and a handle 31;

step 4: surface machining: machining two opposite surfaces 301, 302 of the head 30 of the basic form 3;

step 5: drilling: drilling a hole 103 in the head 30 and making a recess 304 defined in the surface 301 of the head 30;

step 6: prototype 3′;

step 7: contouring: contouring the basic form 3 to include the head 10, the handle 11 and the grip portion 12;

step 8: heat treatment: proceeding heat treatment (annealing) to the prototype 3′;

step 9: surface grinding: for grinding surfaces of the prototype 3′ to obtain a clean surface condition;

step 10: final surface treatment: proceeding final surface treatment by way of sand blowing or vibrating;

step 11: plastic part installation: putting the prototype 3′ in a mold (not shown) and plastic material 4 being introduced to cover the head 30, the handle 31 and the grip portion 32, and step 12: obtaining a product.

It is noted that steps 7, 9 and 10 are optional so that less number of steps is needed to make a wrench. The handle 31 of the prototype 3′ is smaller than the conventional wrench so that less material is needed. Besides, different colors of the plastic material are available and combined with the wrench so that the wrench of the present invention is more competitive.

As shown in FIG. 5 which shows another embodiment of the method wherein the step of plastic part installation can be replaced with the step of coating. The prototype 3′ of the present invention is dip in a container filled with liquid plastic material 4 which is coated to the head 30, the handle 31 and the grip portion 32.

While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.