The present application claims priority under 35 USC §119 to Chinese applications 2008201667154 filed Nov. 13, 2008, which is incorporated herein by reference.
The present invention relates to an improved ratchet driving mechanism.
Tools are often utilized to insert and remove fasteners. The tools include ratcheting mechanisms which enable the tool to apply force to the fastener when the tool is rotated in one direction, and to allow the tool to rotate freely without applying a force to the fastener in the opposite direction. Ratcheting mechanisms of this type take one of two forms. One type uses detents. A detent uses linear motion to engage the teeth. The detent is linearly urged by a spring into the teeth of the ratchet. The other form uses a pawl. The pawls are pivoted outward by a spring to engage the teeth. Each of these embodiments has advantages and disadvantages.
The present invention relates to pawl type ratcheting mechanisms—and specifically a mechanism able to handle more torque than prior art devices. Prior art tools incorporating ratcheting mechanisms of this type are unable to handle large amounts of torque without the teeth on the gear slipping past the pawls. Thus, for fasteners that are very tightly engaged with an item, mechanisms of this type effectively cannot be used to adjust, insert or remove the fasteners. Further, the prior art ratcheting mechanisms require a large number of parts to be assembled within the housing which increases the time and expense necessary for manufacturing tools incorporating these prior art ratcheting mechanisms.
Accordingly, there is a need for a simple easy to assemble ratchet driving mechanism able to handle more torque than prior devices.
In accordance with one aspect of the present invention, an embodiment of the invention includes a ratcheting driver comprised of a cylindrical main body formed with a cylindrical seat. The main body has two opposing channels which extend downward to the seat. Two pawls, disposed in the respective channels rotate about the channel and are formed to engage the ratcheting teeth of the head.
In one embodiment, the pawls are urged outwardly by biasing elements. A biasing hole formed on a side wall in each channel receives a biasing element. In an alternate embodiment a single biasing element urges the pawls outward. The outwardly urged pawl engages teeth located in the ratchet head. An adjusting ring determines which pawl engages the teeth. The ring is concentrically positioned on the body has three indentations to receive a projectile. While one pawl engages the ratcheting teeth, the other pawl is pushed inward and disengaged by an edge in the adjusting ring.
These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:
Referring to
The front portion 5b of main body 5 engages the ratcheting head 1 and is secured to the head 1 by a retaining ring 3. The front portion 5b includes a beveled face 39 (
Two parallel opposing channels 56 are cut into the front portion 5b of the main body 5. Each channel 56 extends from the face 39 longitudinally toward the ring 5a and is offset a distance from the center axis of the main body 5. Each channel 56 has a flat face 56a that extends downward until forming a cylindrical portion 51 shaped to receive a pawl 4, described below. The cylindrical portion 51 of the channel 56 has a slight lip 51a (
When the pawl 4 is urged outward it engages the teeth 11. The ratcheting mechanism has two pawls 4 one for clockwise the other for counter-clockwise rotation. The respective pawl 4 that engages the teeth 11 depends upon the position of the adjusting ring 2 (discussed below). When one of the two pawls is engaged the other pawl is disengaged.
As best seen in
When one pawl 4 is disengaged the other pawl 4 is engaged. The second section 43 of the pawl 4 engages the teeth 11 in the rotatable head 1 by being pivoted outward by the biasing element 6. The biasing element 6 is retained in a hole 52 formed in the flat face of each of the channels 56, such that the hole 52 is in communication with the channel. In an embodiment the biasing element 6 is a spring 6.
Ratcheting is accomplished by the section 43 of the pawl 4 engaging the teeth 11. The teeth 11 and pawl 4 are each slanted at angle, such that when the teeth 11 are rotating in one direction, the pawl 4 slides up and over each tooth 11 in turn, and the biasing element 6 forces the pawl 4 back outward. When the teeth 11 are moving in the other direction, the mating angles of the pawl 4 and teeth 11 stop the rotation of the teeth 11. The angles are mated in such a way as to minimize bending stress to the pawl 4. Instead, the pawl receives primarily compression stress transferred linearly from the teeth 11 through the pawl 4.
The head 1 of the ratcheting mechanism includes inner teeth 11 and a recess 31 (
Direction of ratcheting is changed by turning the adjusting ring 2, which has an ergonomic outer portion 24 to assist the user with gripping the ring 2. A projectile hole 54 (
When the adjusting ring 2 is in either clockwise or counter-clockwise rotation one of the respective pawls 4 abuts an edge 26 in the adjusting ring 2. For example, referring to
The back portion 5c of the main body 5 is the engagement end which securely fastens the main body 5 with the tool handle. In an embodiment shown, the engagement end is formed with four rows of linear teeth 53 adapted to fasten and engage a receiving end of the handle body. The engagement end is inserted and secured into the receiving end 102. The linear teeth 53 securely fix the main body 5 of the ratchet with the handle body. One skilled in the art would recognize any means of securing the main body to the handle body may be employed. For example, the main body could be threaded. Alternatively, the handle body and main body 5 could be formed from a single piece of material.
An alternate embodiment of the invention is illustrated in
In the alternate embodiment, the front position 5b of main body 5 is formed with a recess 55. The recess 55 begins at the front face of main body 5 and extends into the main body 5 between channels 56. The recess 55 is in communication with the flat faces 56a of the channels 56, such that the biasing element 6 extends outward to engage the pawls 4 disposed in the cylindrical portions 51 of the channels 56. In some embodiments, the recess 55 is adapted to receive a spring retainer 9. In such embodiments, the biasing element 6 is a spring.
The spring retainer 9 is illustrated in
While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.
Number | Date | Country | Kind |
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200820166715.4 | Nov 2008 | CN | national |