Patent Application
20110100165
The present invention relates to a one-direction ratchet wrench, particularly to a one-direction ratchet wrench which applies a pin and an elastic assembly to effectively control workpieces being driven in one-direction and also has advantages such as simplified components, easy for assembly and reduced cost.
According to the prior art of a one-direction ratchet wrench disclosed in U.S. Pat. No. 6,539,825, it comprises a driving head with a ratchet wheel and a pawl, and a drive member mounted in the hole of the head. Inasmuch as an elastic element is attached between the drive member and the pawl for biasing the teeth of the pawl to engage with the teeth of the drive member, the head can be employed to drive the ratchet wheel moving in single direction. Apparently, it lacks of sufficient elasticity between the drive member and the head. On the other hand, because the drive member can move freely relative to the head, the elasticity of the elastic element is not able to be effectively applied on the pawl. During the driving process, the drive member bears reacting force to rotate freely and causes extremely unstable situation. Not only can it generate noise, but also damage components easily. Furthermore, there is no mechanic design for pincers to take out the annular hook from the head, and it causes inconvenience for maintaining the components inside the head. It is difficult to drill holes for the drive member to be pinned on, and it increases cost as well.
The first object of the present invention is to provide a one-direction ratchet wrench which applies a pin and an elastic assembly to effectively control workpieces being driven in single direction and also has advantages of simplified components, easy for assembly and reduced cost. In order to achieve the foregoing object, a ratchet wheel is rotatably mounted in a first cavity of a driving head and on a sidewall, near the handle of the wrench, of the first cavity has a second cavity for a pawl to be mounted. There are walls on the top and the bottom portions of the second cavity, and a pin hole is extended from the second cavity to the walls. A pin located in the second cavity is inserted through the pin hole and is held by an elastic assembly, which includes a first elastic element linking with a second elastic element. The first elastic element hitches on the pin, and one of its distal ends extends an elastic push element to stick against the wall of the second cavity. One distal end of the second elastic element is connected with the pawl.
The second object of the present invention is to provide a one-direction ratchet wrench which is easy for assembly and maintenance. In order to achieve the foregoing object, a convex trough is defined on the top wall. The convex trough communicates with a first annular groove, and two free ends of an annular hook are extended into the convex trough. Therefore, pincers can reach in thru-holes of the free ends on the annular hook to detach the annular hook.
Referring to
The head 10 with a penetrated hole, first cavity 11, is extended from one end of a handle 100. There is a curved second cavity 12 with a smaller diameter on a sidewall of the first cavity 11, and the center of the second cavity 12 is located within the first cavity 11 area. A top wall 120 and a bottom wall 121 are formed on the top and the bottom portions of the second cavity 12 respectively. The second cavity 12 communicates with the first cavity 11 whose inner sidewall has a first annular groove 13 near its top portion and a protruded annular fringe 14 near the bottom. The top wall 120 has a curved convex trough 15 whose center is on the same axis as the center of the second cavity 12, and the diameter of the convex trough 15 is less than or equal to the diameter of the second cavity 12. The convex trough 15 relatively communicates with the first annular groove 13. The top wall 120 has a pin hole 16, whose top portion links both the second cavity 12 and the convex trough 15 and bottom portion ends at the top indent of the bottom wall 121.
The ratchet wheel 20 is rotatably mounted in the first cavity 11 of the head 10, and it is held by the annular fringe 14 to avoid falling apart from the wrench. There is a plurality of ratchet teeth 21 distributed on the outer periphery of the ratchet wheel 20, and there is a receptacle 22 formed at the middle of the ratchet wheel 20. The receptacle 22 is employed to receive and drive workpieces. A second annular groove 23 is at the top portion of the outer periphery of the ratchet wheel 20 and is located exactly corresponding to the first annular groove 13. Referring to
The pawl 30 is located in the second cavity 12 of the head. One of its sides has a plurality of teeth 31 engaged with the ratchet teeth 21 and the other side has a protruded column 32.
The pin 40 is a cylindrical pillar and is inserted in the pin hole 16.
The elastic assembly 50 is placed inside the second cavity 12 and it comprises a first elastic element 52 and a second elastic element 51. The first elastic element 52 has a first end, a second end and a first loop 520 extending through the first end and the second end. A push element 53 is extended outwards from the first end in the opposite direction of the first loop 520 which is employed to hold onto the pin 40. The push element 53 is elastic and it is stuck against the wall of the second cavity 12. When the push element 53 sticks against the wall of the second cavity 12, it will generate elasticity to make the first elastic element 52 generate a torque relative to the pin 40. The second elastic element 51 also has a first end, a second end and a second loop 510. The second loop 510 extends through the first end and the second end. The first end of the second loop 510 links with the second end of the first elastic element 52, and the second end of the second loop 510 is a free end employed to connect with the pawl 30. There is a ninety degree angle between the axis of the second loop 510 and the axis of the first loop 520. The second elastic element 51 is effectively connected with the pawl 30 due to the torque from the first elastic element 52 pushing the second elastic element 51. Referring to
The C shaped annular hook 60 is flexible. Its outer periphery is engaged in the first annular groove 13, and its inner periphery is engaged in the second annular groove 23. In as much as the ratchet wheel 20 is held by the annular hook 60, it is rotatably mounted within the first cavity 11. The two free ends of the annular hook 60 are extended into the convex trough 15, and there are two thru-holes 61 formed in the two ends for pincers to reach in. Both of the thru-holes 61 are located in the convex trough 15 as well.
The shape of the lid 70 is in accordance with the contour of the convex trough 15. The top of the lid 70 is pressed and secured by the two free ends of the annular hook 60, so the lid 70 is able to cover the convex trough 15 to seal up the pin 40.
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The pin 40 is inserted into the pin hole 16 of the head 10. When the annular hook 60 is engaged with the first annular groove 13, one of its free ends will stick against the top of the pin 40 to make the pin 40 to secure in the pin hole 16. Another way to position the pin 40 is to apply adhesive on the pin 40 and glue it in the pin hole 16.
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Based upon above designs, the advantages of the present invention are summarized as bellow:
1. The present invention utilizes an elastic assembly 50 to make the pawl 30 engage with the ratchet wheel 20 for the objective of one-direction control, but the prior art disclosed in U.S. Pat. No. 6,539,825 needs three components to achieve the same objective. Therefore, the present invention uses fewer components and saves the cost for assembly.
2. In the present invention, a larger tolerance is allowed for the position and the diameter of the pin 40, but the function of one-direction control is not affected. The surfaces of the walls 120, 121 are flat and are easy for the pin hole 16 to be drilled. Therefore, the manufacturing process can be easier and more effective.
3. The elastic assembly 50 of the present invention is made of metal wire or metal sheet which doesn't require complicated manufacturing process, so that the cost can be reduced.
4. In the present invention, the first elastic element 52 of the elastic assembly 50 is hitched on the pin 40, and its height can be employed to centrally locate the second end of the second elastic element 51 relative to the pawl.
5. In the present invention, the first elastic element 52 of the elastic assembly 50 is hitched on the pin 40, and the push element 53 is stuck against the wall of the second cavity 12 for the elastic assembly 50 to be positioned in the second cavity 12 without contacting the ratchet wheel 20 and causing friction. It makes the assembly process easier.
6. In the present invention, the head 10 has a convex trough 15 that allows the free ends of the annular hook 60 to be mounted. Therefore, if any inner component is damaged, it can be replaced by opening the convex lid 80, dismounting the free ends of the annular hook 60 with pincers, and unloading the ratchet wheel 20.
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.
