A pair of locking pliers includes a first grip structure including a first jaw and an adjustment screw connected to a first handle. A second grip structure cooperates with the first grip structure. The second grip includes a second jaw pivotally connected to the first handle about a first pivot axis and a second handle pivotally connected to the second jaw about a second pivot axis. A lock mechanism is pivotally connected to the second handle about a third pivot axis. The lock mechanism abuts the adjustment screw which restrains the lock mechanism to the first handle. The second handle extends longitudinally and terminates at an end at a first length from the second pivot axis. A second length measures a distance between the second and third pivot axes. The second length is smaller than 0.19 times of the first length.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a pair of locking pliers and, more particularly to a pair of effort-saving locking pliers.

2. Description of the Related Art

TW Pat. No. I411498 shows a pair of locking pliers including two jaws, two handles connected respectively to the two jaws, and a locking mechanism connected between the two handles. The handles can be squeezed to close the jaws. The pair of locking pliers can be locked to an object, with the locking mechanism causing the jaws to be clamped to the object. However, a great effort is still needed to release the pair of locking pliers from the clamped object.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide a pair of effort-saving locking pliers. The pair of locking pliers includes a first grip structure including a first handle, a first jaw connected to and fixedly disposed on the first handle, and an adjustment screw connected to the first handle and being movable to various fixed positions on the first handle. A second grip structure cooperates with the first grip structure. The second grip includes a second jaw pivotally connected to the first handle about a first pivot axis and a second handle pivotally connected to the second jaw about a second pivot axis. The second jaw is pivotal relative to and faces the first jaw. A lock mechanism is connected between the first and second handles. The lock mechanism is pivotally connected to the second handle about a third pivot axis. The lock mechanism abuts the adjustment screw which restrains the lock mechanism to the first handle. A biasing member is connected between the first handle and the second jaw. The second handle extends longitudinally and terminates at an end at a first length from the second pivot axis. A second length measures a distance between the second and third pivot axes. The second length is smaller than 0.19 times of the first length.

Other objectives, advantages, and new features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanied drawings.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 3show a pair of locking pliers10according to a first embodiment of the present invention. The pair of locking pliers10includes a first grip structure20, a second grip structure30, a lock mechanism33, and a biasing member34.

The first grip structure20includes a first handle21, a first jaw22connected to and fixedly disposed on the first handle21, and an adjustment screw23connected to the first handle21and being movable to various fixed positions on the first handle21. The first handle21has two opposite ends. The first jaw22and the adjustment screw23are at opposite ends of the first handle21. The first handle21extends in a lengthwise direction from a first end to a second end thereof. The first jaw22extends in a lengthwise direction from a first end to a second thereof. The first handle21includes the first end thereof connected to the second end of the first jaw22. The first end of the first jaw22is at a first distal end of the pair of locking pliers10, and the second end of the first handle21is at a second distal end of the pair of locking pliers10, respectively. The pair of locking pliers10measures a longitudinal length LT from the first end of the first jaw22to the second end of the first handle21. The first handle21has a thread hole24extending therein. The adjustment screw23is threadably engaged with the thread hole24about an axis E. The first jaw22includes a first plurality of teeth. A first phantom line joining apexes of the first plurality of teeth is curved.

The second grip structure30cooperates with the first grip structure20. The second grip structure30includes a second jaw31pivotally connected to the first handle21about a first pivot axis C1and faces the first jaw22. The first pivot axis C1is defined on a fastener engaging the second jaw31and the first handle21. The fastener inserts through a hole extending through the second jaw31and a hole extending through the first handle21. The second grip structure30also includes a second handle32pivotally connected to the second jaw31about a second pivot axis C2. The first pivot axis C1is parallel to the second pivot axis C2. The second handle32has a structure including a base seat and a pair of wings extending from the base seat. The base seat and the pair of wings cooperate to form a concavity. The second pivot axis C2is defined on a fastener35inserting through a hole extending through the second jaw31and a hole extending through the wings of the second handle32. The second jaw31includes a second plurality of teeth. A second phantom line joining apexes of the second plurality of teeth is curved.

The lock mechanism33is connected between the first and second handles21and32. The lock mechanism33is pivotally connected to the second handle32about a third pivot axis C3. The third pivot axis C3is parallel to the second pivot axis C2. The third pivot axis C3is defined on a fastener36inserting through a hole extending through the second handle32and a hole extending through the lock mechanism33. The lock mechanism33abuts the adjustment screw23which restrains the lock mechanism33to the first handle21. The lock mechanism33is a linkage made in one piece. The lock mechanism33includes a protrusion extending rearward therefrom. The protrusion releasably abuts the second handle32.

The biasing member34connected between the first handle21and the second jaw31. The biasing member34has two opposite distal ends. The biasing member34includes a first distal end thereof hooked to a protrusion of the first handle21and a second end thereof hooked to a hole recessing on the tail end of the second jaw31.

The pair of locking pliers10is movable between an open position in which the second jaw31is disposed distal to the first jaw22and in which an opening of a first size is delimited between the first and second jaws22and31, and a locked position in which the second jaw31is disposed closer to the first jaw22and in which the size of the opening is reduced. The pair of locking pliers10moved to the open position thereof includes the second pivot axis C2, the third pivot axis C3, and an end of the lock mechanism adjacent to the adjustment screw23not aligned. The pair of locking pliers10moved to the locked position thereof includes the lock mechanism33disposed in an overcenter lock position in which the second pivot axis C2, the third pivot axis C3and the end of the lock mechanism adjacent to the adjustment screw23substantially aligned. The pair of locking pliers10moved to the locked position thereof includes the first ends of the first and second jaws22and31aligned with each other. The pair of locking pliers10moved to the open position thereof includes the protrusion not in contact with the second handle32. The pair of locking pliers10moved to the locked position thereof includes the protrusion in contact with the second handle32.

The second handle32extends longitudinally and terminates at an end at a first length L1from the second pivot axis C2. A second length L2measures a distance between the second and third pivot axes C2and C3. The second length L2is smaller than 0.19 times of the first length L1. Preferably, the second length L2is smaller than 0.15 times and greater than 0.1 times of the first length L1. Preferably, the second length L2is smaller than 0.14 times and greater than 0.13 times of the first length L1.

In addition, the lock mechanism33terminates at an end abutting the adjustment screw23at a third length L3from the third pivot axis C3. The third length L3is greater than 0.6 times of the first length L1. Preferably, the third length L3is smaller than 0.75 times of the first length L1. Preferably, the third length L3is greater than 0.65 times and smaller than 0.7 times of the first length L1.

Furthermore, the first length L1is smaller than 0.8 times and greater than 0.7 times of the longitudinal length LT.

The pair of locking pliers10includes the second length L2thereof smaller than 0.19 times of the first length L1thereof to be effort-saving. The effort-saving pair locking pliers10in the locked position thereof allows an object to be clamped tightly between the first and second jaws22and31. It is effort-saving to release the pair of locking pliers10from the clamped object.

FIGS. 4 through 6show a pair of locking pliers10aaccording to a second embodiment of the present invention, and the same numbers are used to correlate similar components of the first embodiment, but bearing a letter a. The second embodiment is the same as the first embodiment except that a lock mechanism33areplaces the lock mechanism33. The second embodiment has the same arrangements and geometries as the first embodiment. Therefore, similarity is not described repeatedly.

The lock mechanism33aincludes a first linkage331aand a second linkage332apivotally connected to the first linkage331aabout a fourth pivot axis C4. The fourth pivot axis C4is parallel to the third pivot axis C3. The first linkage331ais pivotally connected to the second handle32aabout the third pivot axis C3defined by a fastener36aand to the second pivot C2defined by a fastener35a. The first linkage331aincludes a lower wall and a pair of side walls extending in the transverse direction from the lower wall. The second linkage332ais pivotally connected between the pair of side walls. The fourth pivot axis C4is defined on a fastener37ainserting through a hole extending through the side walls of the first linkage331and a hole extending through a head end of the second linkage332a. The first linkage331aincludes a power end which is spaced from the lower wall in a transverse direction. The power end releasably abuts the second handle32a. The second linkage332aincludes a protrusion extending rearward therefrom. The protrusion releasably abuts the second handle32a. The adjustment screw23aabuts the second linkage332a.

The pair of locking pliers10amoved to an open position thereof includes the power end not in contact with the base seat. The pair of locking pliers moved to a locked position thereof includes power end in contact with the base seat.

In view of the forgoing, the effort-saving pair of locking pliers10or10aincludes the second length L2thereof smaller than 0.19 times of the first length L1thereof. The effort-saving pair locking pliers10or10ain the locked position thereof allows an object to be clamped tightly between the first and second jaws22and31. It is effort-saving to release the pair of locking pliers10or10afrom the clamped object.