Patent Application
20220152786
The present invention relates to a hand tool and, more particularly, to a pair of plumbing pliers.
Referring to
A “bite size” is the distance between the jaws of the levers 1 and 2 when the handles of the levers 1 and 2 are located as close to each other as possible. The bite size is expected to be marginally smaller than a diameter of a pipe so that the pair of plumbing pliers can tightly bite (or “clamp”) the pipe. The bite size of the pair of plumbing pliers is adjusted in compliance with various diameters of pipes.
Referring to
Referring to
A problem is however encountered in the use of the pair of plumbing pliers. When the pair of plumbing pliers is opened to receive a pipe, or when the pair of plumbing pliers is opened to release the pipe before the pair of plumbing pliers is closed to clamp the pipe again, there is a risk that the lever 2 could be excessively pivoted away from the lever 1 so that the lever 2 rotates the C-shaped spring 5 that in turns disengages the pawl 6 from the ratchet teeth 3. Accidentally, the lever 2 is allowed to move relative to the lever 1 and change the bite size of the pair of plumbing pliers.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.
It is the primary objective of the present invention to provide a reliable pair of plumbing pliers.
To achieve the foregoing objective, the pair of plumbing pliers includes two levers and a pawl. Each of the levers includes a jaw, a handle, a shank formed between the jaw and the handle. The first lever includes a rectilinear slot in the shank thereof and ratchet teeth along an edge of the rectilinear slot. The second lever includes an arched slot in the shank thereof. The shanks of the first and second levers are pivotally connected to each other. The pawl is inserted in the rectilinear slot and pivotally connected to the shank of the second lever and comprises ratchet teeth for engagement with the ratchet teeth of the first lever. The pawl includes a recess and a boss movably inserted in the arched slot. The torque spring includes a first terminal section inserted in the recess and a second terminal section abutted against another edge of the rectilinear slot so that the torque spring brings the ratchet teeth of the pawl into engagement with the ratchet teeth of the first lever. In a first range of pivoting the handle of the second lever relative to the handle of the first lever, a closed end of the arched slot is not in contact with the boss to keep the ratchet teeth of the pawl engaged with the ratchet teeth of the first lever to prevent downward movement of the shank of the second lever relative to the shank of the first lever. In a second range of pivoting the handle of the second lever relative to the handle of the first lever, the closed end of the arched slot is in contact with the boss to disengage the ratchet teeth of the pawl from the ratchet teeth of the first lever to allow downward movement of the shank of the second lever relative to the shank of the first lever.
Other objectives, advantages and features of the present invention will be apparent from the following description referring to the attached drawings.
The present invention will be described via detailed illustration of the preferred embodiment referring to the drawings wherein:
Referring to
The lever 20 includes a handle 25 formed at an end, a jaw 28 formed at another end, and a shank 26 formed between the handle 25 and the jaw 28. The lever 20 is further formed with a rectilinear slot 21 in the shank 26. The rectilinear slot 21 extends between two edges 22 and 24. There are ratchet teeth 23 formed along an edge of the rectilinear slot 21.
The lever 30 includes a handle 33 formed at an end, a jaw 38 formed at another end and a shank 34 between the handle 33 and the jaw 38. The lever 30 further includes an aperture 31 and an arched slot 32 in the shank 34. The arched slot 32 extends about the aperture 31. The arched slot 32 includes two closed ends.
The pawl 40 is formed with ratchet teeth 41, two shafts 42 and 45, a recess 43 and a boss 44. The ratchet teeth 41 are formed at an edge of the pawl 40. The shaft 42 and the boss 44 are formed on a first side of the pawl 40. The recess 43 is made in the first side of the pawl 40. The shaft 45 is formed on a second side of the pawl 40. The shafts 42 and 45 are coaxial with each other.
The torque spring 50 includes two terminal sections 51 and 52 and a helical portion (not numbered) formed between the terminal sections 51 and 52. The terminal section 51 is a rectilinear section. The terminal section 52 is bent at an end. Preferably, the terminal section 51 extends shorter than the terminal section 52.
The positioning plate 70 includes an orifice 71 corresponding to the aperture 31 of the lever 30.
In assembly, the helical portion of the torque spring 50 is located around the shaft 42 of the pawl 40. The terminal section 51 is inserted in the recess 43.
The pawl 40 is inserted in the rectilinear slot 21 of the lever 20. Thus, the ratchet teeth 41 are engaged with some of the ratchet teeth 23. Moreover, the terminal section 52 of the torque spring 50 is in contact with the edge 24 of the rectilinear slot 21 of the lever 20.
The shank 26 of the lever 20 is located next to the shank 34 of the lever 30. Thus, the shaft 42 of the pawl 40 is inserted in the aperture 31 of the lever 30. Furthermore, the boss 44 is inserted in the arched slot 32. The first closed end of the arched slot 32 is located closer to the terminal section 51 of the torque spring 50 than the second closed end of the arched slot 32 is. The second closed end of the arched slot 32 is located in the vicinity of the terminal section 52 of the torque 50 than the first closed end of the arched slot 32 is.
The positioning plate 70 is located next to the shank 26 of the lever 20. Thus, the shank of the lever 20 is located between the positioning plate 70 and the shank 34 of the lever 30.
The pivots 72 that are preferably rivets are fitted in two apertures (not numbered) of the positioning plate 70 and two additional apertures (not numbered) of the shank 34 of the lever 30 to keep the shank of the lever 20 between the positioning plate 70 and the shank 34 of the lever 30. Thus, the levers 20 and 30 are movably connected to each other.
Referring to
On the contrary, the shape of ratchet teeth 23 and 41 prevents the pawl 40 from moving downward along the shank 26 of the lever 20. Thus, the bite size of the pair of plumbing pliers cannot be enlarged.
Now, the boss 44 of the pawl 40 is not in contact with any of the closed ends of the arched slot 32 when the ratchet teeth 41 are engaged with some of the ratchet teeth 23. The jaw 30 can be pivoted away from the jaw 20 before one of the closed ends of the arched slot 32 is brought into contact with the boss 44 referring to
Referring to
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Secondly, referring to
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After adjusting the desired bite size according to a diameter of a pipe, the user pivots the handle 33 relative to the handle 25 in the first range to clamp and release the pipe repeatedly to rotate the pipe. To adjust the bite size of the pair of plumbing pliers according to a diameter of another pipe, the user pivots the handle 33 relative to the handle 25 in the second range and moves the shank 34 of the lever 30 relative to the shank 26 of the lever 20. As described above, the user feels little resistance in the first range but feels considerable resistance in the second range. Hence, the user can easily detect the difference between the first and second ranges. Accordingly, it is not likely that the user will, by mistake, enter the second range, i.e., increase the bite size of the pair of plumbing pliers.
The present invention has been described via the illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.
