1. Field of the Invention
The present invention relates to a reversible ratcheting tool having a smaller head and improved driving torque for convenient use in a limited space.
2. Description of the Related Art
A wide variety of ratcheting tools have heretofore been disclosed. Typical examples include: U.S. Pat. No. 1,957,462 to Kress issued on May 8, 1934; U.S. Pat. No. 4,328,720 to Shiel issued on May 11, 1982; U.S. Pat. No. 5,626,062 to Colvin issued on May 6, 1997; U.S. Pat. No. 4,762,033 to Chow issued on Aug. 9, 1988; U.S. Pat. No. 4,520,697 to Moetteli issued on Jun. 4, 1985; U.S. Pat. No. 3,337,014 to Sandrick issued on Aug. 22, 1967; and U.S. Pat. No. 5,144,869 to Chow issued on Sep. 8, 1992. Most of the above-mentioned conventional ratcheting tools fail to provide high torque operation, as the pawls merely engage with the ratchet wheel by at best three or five teeth. The head of the ratcheting tool has to be relatively large for accommodating those components and thus is difficult to be used in a limited space. In addition, the pawl is directly driven by the switch button or reverser plate or like element such that the pawl tends to be disengaged from the ratchet wheel or like element if the switch block is inadvertently impinged. Generally, a skilled user uses a combination wrench, a spanner with two open ends, or a ring spanner for tightening or loosening a fastener in a limited space. Yet, it is found that free rotation of the ratcheting tool during ratcheting is too large (larger than the theoretic value of 5°), as the pawl has a long travel.
U.S. Pat. No. 6,431,031 issued on Aug. 13, 2002 discloses a reversible ratcheting tool with a smaller head to solve the above problems.
Referring to
The present invention is intended to provide an improved design in this regard to improve the driving torque for reliable high-torque operation.
It is a primary object of the present invention to provide a reversible ratcheting tool with a small head while providing improved driving torque for convenient use in a limited space.
A ratcheting tool in accordance with the present invention comprises:
a handle;
a head extended from the handle and having a compartment therein;
a drive member including a first end extended beyond the compartment, a second end extended beyond the compartment, and a gear wheel formed between the first end and the second end, the gear wheel being rotatably mounted in the compartment and including an outer periphery with a plurality of first teeth;
a pawl mounted in the compartment and including a first side with a plurality of second teeth facing the first teeth of the gear wheel and a second side facing away from the gear wheel, the second teeth of the pawl including a first teeth portion having a first center of curvature and a second teeth portion having a second center of curvature located at a position different from the first center of curvature;
a ring mounted in the compartment and around the first end of the drive member, the ring being operably connected to the pawl such that the ring and the pawl are pivotable about a rotational axis of the gear wheel and that the pawl is movable in a radial direction relative to the ring;
a reversing plate mounted to the first end of the drive member and pivotable about the rotational axis of the gear wheel between a first position and a second position;
means for retaining the reversing plate in position; and
means for providing transmission between the reversing plate and the pawl for moving the pawl between a first ratcheting position and a second ratcheting position, wherein the first teeth portion of the pawl is engaged with the first teeth of the gear wheel for ratcheting in a first direction and the second teeth portion of the pawl is disengaged from the first teeth of the gear wheel when the pawl is in the first ratcheting position, and wherein the second teeth portion of the pawl is engaged with the first teeth of the gear wheel for ratcheting in a second direction opposite to the first direction and the first teeth portion of the pawl is disengaged from the first teeth of the gear wheel when the pawl is in the second ratcheting position.
The first center of curvature of the pawl is coincident with a center of the gear wheel when the pawl is in the first ratcheting position. The second center of curvature of the pawl is coincident with the center of the gear wheel when the pawl is in the second ratcheting position. Thus, the total number of pawl teeth actually and reliably engaged with the gear wheel in accordance with the present invention during ratcheting is greater than that in conventional designs, and such advantage is the result of the novel design in the first and second teeth portions of the pawl.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Referring to
Rotatably mounted in the head 12 is a drive member 20 having an upper end 22, a drive column 23 on a lower end thereof, and a gear wheel 21 formed in an intermediate portion thereof. The gear wheel 21 is rotatably received in the first compartment 131 of the head 12 and includes teeth 211 formed on an outer periphery thereof. The upper end 22 of the drive member 20 includes an engaging groove 221, and an annular groove 222 is defined in a side of the gear wheel 21. The drive column 23 includes a hole 231 for receiving a ball 232. The drive member 20 further includes a central through-hole 24 with a shoulder portion 241, which will be described later.
Still referring to
A pawl 30 is mounted in the second compartment section 132 and includes a side facing the gear wheel teeth 211. Referring to
Still referring to
A reversing plate 50 is mounted around the upper end 22 of the drive member 20 and includes a hole 51 and a thumb piece 52. As illustrated in
A retaining means 60 is mounted in the receptacle 524 of the thumb piece 52 and includes a substantially U-shape slide piece 61 and an elastic member 62. The slide piece 61 includes a tapered push-face 611 consisting of two faces (not labeled) separated by a tip (not labeled, see
A pin 5211 is inserted through the through-hole 521 of the thumb piece 52 with a lower end of the pin 5211 extended through the arcuate groove 523 and into the hole 16 of the head 12. Thus, the pin 5211 is retained in the hole 16. As a result, the arcuate groove 523 is movable relative to the pin 5211 during pivotal movement of the reversing plate 50. The push-face 611 of the slide piece 61 may retain the pin 5211 in place. In addition, as the pin 5211 is retained in place and the positioning piece 511 of the reversing plate 50 is engaged in the engaging groove 221 of the drive member 20, the reversing plate 50 is securely yet pivotally engaged with the upper end 22 of the drive member 20.
A transmission member 70 is provided to convert manual pivotal movement of the reversing plate 50 into pivotal movement of the pawl 30 about the rotational axis of the gear wheel 21. In this embodiment, the transmission member 70 is in the form of a spring having a relatively small pitch. The transmission member 70 is extended in the through-hole 522 of the reversing plate 50, the rectangular opening section 142 of the head 12 of the handle 11, and the notch 42 of the ring 40 and then into the annular groove 222 of the drive member 20.
When the reversing plate 50 is in a position shown in
Referring to
When the reversing plate 50 is moved to a position shown in
When the reversing plate 50 is moved to a position shown in
Referring to
Referring to
It is appreciated that the pawl 30 engages with the gear wheel 21 by ten (10) teeth and thus may bear higher torque during ratcheting. It is noted that the push-face 611 of the slide piece 61, under the action of the elastic member 62, retains the ring 40 as well as the pawl 30 in place to provide reliable ratcheting. Yet, the tip piece 41 of the ring 40 and the recess 33 of the pawl 30 are configured to allow the pawl 30 to be moved away from the gear wheel 21 in a radial direction during non-driving rotation of the handle. Accordingly, the user must apply a relatively larger force to switch the reversing plate 50, yet this also prevents inadvertent impingement to the thumb piece 52 that may cause undesired movement of the pawl 30.
According to the above description, it is appreciated that the ratcheting tool in accordance with the present invention may bear much higher torque and has minimized head size that is very useful when operating in a limited space. In addition, the ratcheting direction can be changed by easy operation of the reversing plate. The arrangement for achieving the ratcheting direction switching is simple yet requires a relatively larger force to prevent inadvertent switching. Of more importance, the total number of pawl teeth actually and reliably engaged with the gear wheel in accordance with the present invention during ratcheting is greater than that in conventional design, and such advantage is the result of the novel design in the first and second teeth portions 31 and 32 of the pawl 30.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
Number | Date | Country | Kind |
---|---|---|---|
89200570 U | Jan 2000 | TW | national |
This application is a division of U.S. application Ser. No. 09/523,625 filed Mar. 13, 2000 now U.S. Pat. No. 6,457,387.
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Number | Date | Country | |
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Parent | 09523625 | Mar 2000 | US |
Child | 10219135 | US |