Open wrench

An open wrench includes a head having a handle and a driving portion which has an opening. A first layer, a second layer, a third layer and a fourth layer are formed on each of the top and the bottom of the driving portion. The first layer and the second layer are located along the U-shaped opening of the head. The top face of the second layer is smaller than that of the first layer. The third layer extends from the middle portion of the first layer, and the fourth layers extends from the middle portion of the second layer. The top face of the fourth layer is smaller than that of the third layer. The open wrench is light in weight and strong in structure, and is able to output significant torque to objects.

BACKGROUND OF THE INVENTION

1. Fields of the Invention

The present invention relates to an open wrench, and more particularly, to an open wrench with less material required while the strength is maintained.

2. Descriptions of Related Art

The conventional open wrench is disclosed inFIG. 21and comprises a head60having a handle61and a driving portion62whose thickness is thicker than that of the handle61. The thicker driving portion62is heavy.FIG. 22shows another open wrench which comprises a head70having a handle71and a driving portion72which includes a first layer721and a second layer722formed thereon. The thickness of the first layer721is the same as that of the handle71. The second layer722is located along the opening of the head70. The second layer722protrudes from the first layer721. The head70meets the standard of German Standard DIN 3113. However, the volume of the head70is smaller than the head60, the wrench cannot output satisfied torque.

The present invention intends to provide an open wrench to eliminate the shortcomings mentioned above.

SUMMARY OF THE INVENTION

The present invention relates to an open wrench and comprises a head having a handle and a driving portion which has an opening. A first layer, a second layer, a third layer and a fourth layer are formed on each of the top and the bottom of the driving portion. The first layer and the second layer are located along the U-shaped opening of the head. The top face of the second layer is smaller than that of the first layer. The third layer extends from the middle portion of the first layer, and the fourth layers extends from the middle portion of the second layer. The top face of the fourth layer is smaller than that of the third layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1 to 4, the open wrench of the present invention comprises a head10which has a handle11and a driving portion12which has a U-shaped opening120defined through a front end, a top and a bottom of the head10. A first layer121and a second layer123are formed on each of the top and the bottom of the driving portion12. The second layer123is formed on the first layer121. The first and second layer121,123are located along the opening120of the head10. The second layer123has a first top face122defined in a top thereof, and the first top face122is a flat face. The first layer121is integrally formed on the flat face of the driving portion12. The periphery of the second layer123extends and is connected to the first top face122inclinedly. The cross sectional shape of the second layer123has two sides and each side is a straight side. The area of the first top face122is smaller than the area of the second layer123, and the area of the second layer123is smaller than the area of the top of the first layer121. A third layer141extends from the middle portion of the first layer121and toward the handle11. A fourth layer143extends from the second layer123and toward the handle11. The fourth layer143is located on the third layer141. The fourth layer143has a second top face142defined in the top thereof, and the second top face142extends toward the handle11. The second top face142is a flat face. The fourth layer143is integrally formed on the third layer141. The third layer141is integrally formed on the flat face of the handle11. The first and second top faces122,142are located on the same plane and form a Y-shaped arrangement. The periphery of the fourth layer143extends and is connected to the second top face142inclinedly. The cross sectional shape of the fourth layer143has two sides and each side is a recessed and curved side. The area of the second top face142is smaller than the area of the bottom of the fourth layer143. The area of the bottom of the fourth layer143is smaller than the area of the bottom of the third layer141.

As shown inFIG. 2, the first top face122is connected to the second top face142at a portion thereof having a first width144. The middle portion of the second top face142has a second width145which is smaller than the first width144. The second top face142has a first curved portion146formed at the distal end thereof, and the diameter of the first curved portion146is smaller than second width145. The bottom of the fourth layer143has a second curved portion147formed at the distal end thereof, and the diameter of the second curved portion147is larger than the diameter of the first curved portion146. The first and second curved portions146,147share a common center.

As shown inFIGS. 3 and 4, first distance31is defined between the two respective first top faces122of the top and bottom of the driving portion12. The cross sectional shape of the second layer123has two sides and each side is a straight side. The cross sectional shape of the fourth layer143has two sides and each side is a recessed and curved side.

As shown inFIG. 5, the bottom of a first curved face127of the opening120of the driving portion12has a bisectional line124passing through the central point of the first curved face127. A reference line125which is parallel to the axial line126of the handle11passes through the central point of the first curved face127. An angle of 15 degrees is defined between the bisectional line124and the reference line125. Namely, the opening120has a first curved face127defined in the inner end thereof, a reference line125which is parallel to the axial line126of the handle11passes through the central point of the first curved face127and intersects the bisectional line124at the central point of the first curved face127. An imaginary second curved face128is defined at the intersection between the first layer121and the handle11. The first and second curved faces127,128are similar and share a common center. The bisectional line124intersects the axial line126at the center of the second curved face128. A shift distance32is formed between the reference line125and the axial line126. Because of the shift distance32, the user can use the open wrench in a narrow space to rotate the object50without being interfered by other objects. A distance between an intersection point between an axial line126of the handle11and the second curved face128to an intersection point between the axial line126and the distal end of the fourth layer143is defined as the second distance36. The ratio between the second distance36to the length37of the handle11is less than 0.5. The ratio between the second distance36to the length37of the handle11is between ⅓ to ⅙. Preferably, the ratio is 1.6.

As shown inFIGS. 6 to 8, the first top face122protrudes from the first layer121. The area42of the first top face122is smaller than the area of the top41of the first layer121. The area42of the first top face122is ⅓ to ⅔ of the area of the top41of the first layer121. The second layer123is connected between the top41of the first layer121to the first top face122. The cross sectional shape of the second layer123has two sides and each side is a straight side or a concaved and curved side. The area44of the second top face142is smaller than the area of the top face43of the third layer141. The fourth layer143is connected between the top face43of the third layer141and the area44of the second top face142. The cross sectional shape of the fourth layer143has two sides and each side is a straight side or a recessed and curved side.

As shown inFIG. 9, when the driving portion12clamps and rotates the object50, the thumb contacts the fourth layer143to easily apply a force to the open wrench.

As shown inFIG. 10, when the driving portion12clamps and rotates the object50, because other objects around the wrench, only a portion of the object50is accommodated in the opening120, the torque is transferred to the handle11and the fourth layer143via the second layer123. The driving portion12has the first, second, third and fourth layers121,123,141,143so that it is lighter than the conventional driving portion62inFIG. 21, and is able to output a higher toque than the driving portion72inFIG. 22.

As shown inFIG. 11, the second top face142extends to the middle portion of the handle11and along the axial line126. The first and second widths144,145are the same, and the second distance36is less than or equal to ½ of the third distance37.

As shown inFIG. 12, the second top face142is located close to one side of the handle11. A gap38is defined between the central line of the second top face142and an axial line126of the handle11.

As shown inFIGS. 13 to 20, the body10has only the first layer121, the first top face122and the second layer123. The third layer141, the second top face142and the fourth layer143are omitted.

As shown inFIG. 1, the top of the first layer121to the lower end of the third layer141is a rounded side or an orthogonal side. The lower end of the second layer123to the first top face122, and the lower end of the fourth layer143to the top face142is rounded side or an orthogonal side.