Patent Application
20170182637
1. Field of the Invention
The present invention relates to a ratchet wrench and, in particular, to a ratchet wrench that is lightweight and that is designed to withstand higher torque requirements.
2. Description of the Related Art
U.S. Pat. No. 3,742,788 shows a ratchet wrench including a main body. The main body has a through hole defining a compartment. A ratchet driving assembly is positioned in the compartment and two plates mounted oppositely on the main body to keep the ratchet driving assembly in the compartment. A pawl of the ratchet driving assembly has a through hole and a fastener inserts through the through hole. The pawl is pivotally anchored to the fastener. Furthermore, the fastener secures the two plates to the main body, with one of two distal ends engaging with one plate and the other distal end engaging with the other plate. Because the pawl is movable relative to the fastener, the fastener can not effectively transmit a torque load from the pawl to the plates. In addition, the pawl is generally of a small size that will not occupy too much space of the compartment and that enables the ratchet wrench to have a compact size. Therefore, the pawl including the through hole has a weak structure and can not withstand high torque requirements.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.
According to the present invention, a ratchet wrench includes a main body made of rigid plastic and including a first opening, a second opening opposite the first opening, a first ledge surface, a second ledge surface opposite the first ledge surface, and a compartment extending therethrough and in communication with the first and second openings. A first plate made of rigid metal has a contour correspondingly matching to a contour of the first opening and is received in the first opening. The first ledge surface supports the first plate. A second plate made of rigid metal has a contour correspondingly matching to a contour of the second opening and is received in the second opening. The second ledge surface supports the second plate. A ratchet driving assembly is received by the compartment and positioned between the first and second plates. The ratchet driving assembly includes a driving member and two pawls. The driving member is rotatable about an axis and includes a gear. The driving member is engaged with an object to be driven upon using the ratchet wrench to drive the object. The two pawls are engagable with the gear of the driving member, and one of the two pawls is configured to allow the driving member to rotate clockwise and to inhibit the driving member from rotating counterclockwise while the other pawl is configured to allow the driving member to rotate counterclockwise and to inhibit the driving member from rotating clockwise. The two pawls are disposed in a mirror image relationship. The two pawls are anchored to the at least one of the first and second plates and are configured to transmit a torque load to the at least one of the first and second plates, with the at least one of the first and second plates forming a first recess in communication with the compartment and the two pawls each forming a first protrusion inserted in the first recess. A direction control engagable with the two pawls and configured to cause each of the two pawls to move to a first position engaging the driving member and a second position disengaging from the from the driving member.
The present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings. It is intended that the embodiments and drawings disclosed herein are to be considered illustrative rather than restrictive.
A ratchet driving assembly 40 is received by the compartment 13 and positioned between the first and second plates 20 and 30. The ratchet driving assembly 40 includes a driving member 41 and two pawls 42. The driving member 41 is rotatable about an axis and includes a gear 411. The driving member 41 is engaged with an object to be driven upon using the ratchet wrench to drive the object. The driving member 41 includes a first driving end 412 extending outside the first plate 20 through a first slot and a second driving end 413 extending outside the second plate 30 through a second slot respectively, and the object to be driven is engaged with one of the first and second driving ends 412 and 413. The first driving end 412 forms a drive extension. The second driving end 413 forms a socket. The two pawls 42 are made of rigid metal and are engagable with the gear 411 of the driving member 41, and one of the two pawls 42 is configured to allow the driving member 41 to rotate clockwise and to inhibit the driving member 41 from rotating counterclockwise while the other pawl 42 is configured to allow the driving member to rotate counterclockwise and to inhibit the driving member 41 from rotating clockwise. The two pawls 42 are disposed in a mirror image relationship. The two pawls 42 are anchored to the at least one of the first and second plates 20 and 30 and are configured to transmit a torque load to the at least one of the first and second plates 20 and 30, with the at least one of the first and second plates 20 and 30 forming a first recess in communication with the compartment 13 and the two pawls 42 each forming a first protrusion 421 inserted in the first recess. The two pawls 42 are pivotally anchored to the at least one first and second plates 20 and 30. Each of the two pawls 42 is under a resilient force of a biasing member 43. The biasing member 43 has a shape including a plurality of coils.
In the embodiment, the other of the first and second plates 20 and 30 forms two second recesses in communication with the compartment 13 and each receive the first protrusions 421 of one of the two pawls 42. It is within the scope of the invention that the two first recesses extending through one of the first and second plates 20 and 30. It is within the scope of the invention that the two second recesses extend through the other of the first and second plates 20 and 30.
A direction control 50 is engagable with the two pawls 42 and is configured to cause each of the two pawls 42 to move to a first position engaging the driving member 41 and a second position disengaging from the from the driving member 41. The direction control 50 includes a projection which extends between the two pawls 42 and which is adapted to move each of the two pawls 42 to counteract the respective biasing member 43. Each pawl 42 includes the projection of the direction control 50 and a first end of the biasing member 43 respectively abutting one of two opposite lateral sides thereof. The biasing member 43 has a second end abutting the main body 10. The main body 10 forms a recess and the second end of the biasing member 43 is positioned in the recess.
A torque-transmitting block 60 is received by the compartment 13. The torque-transmitting block 60 is anchored to the at least one first and second plates 20 and 30 and is configured to transmit a torque load to the at least one of the first and second plates 20 and 30, with the at least one of the first and second plates 20 and 30 forming a first cavity in communication with the compartment 13 and the torque-transmitting block 60 forming a second protrusion 601 inserted in the first cavity. The two pawls 42 are pivotally anchored to the at least one first and second plates 20 and 30 and the respective first protrusion 421 defines a pivot axis. The torque-transmitting block 60 forms two concaves each pivotally receive the first protrusions 421 of one of the two pawls 42. The concaves each have a curved inner periphery and the first protrusion 421 of the respective pawl 42 has a curved outer periphery. The torque-transmitting block 60 is configured to abridge a gap between two opposite lateral sides of the main body 10, with the torque-transmitting block 60 having a lateral side in surface-to-surface contact with an inner periphery of the main body 10. The lateral side of torque-transmitting block 60 is also in surface to surface contract with a wall extending between the two opposite lateral sides of the main body 10. The torque transmitting block 60 abridging the gap between the lateral sides of the main body 10 therefore increases the rigidity of the main body 10. Furthermore, the torque-transmitting block 60 receiving the two pawls 42 helps transmit the torque load to the at least one of the first and second plates 20 and 30. Consequently, the ratchet wrench is able to withstand even higher torque requirements.
In the embodiment, the other of the first and second plates 20 and 30 forms a second cavity in communication with the compartment 13 and receives the second protrusions 601 of one of the torque-transmitting block 60.
A knob 70 is releasably coupled to the driving member 41 and is configured to be rotated to turn the driving member 41. Upon rotating the knob 70 clockwise the driving member 41 is rotated clockwise. Upon rotating the knob 70 counterclockwise the driving member 41 is rotated counterclockwise. With the knob 70, the driving member 41 can be turned in a fast manner without leverage from the main body 10 upon using the ratchet wrench to drive the object. The knob 70 is releasably coupled to the other of the first and second driving ends 412 and 413 of the driving member 41 and configured to be rotated to turn the driving member 41. The knob 70 is coupled to the first driving end 412. The knob 70 includes a hole and the first driving end 412 is inserted in the hole.
The first plate 20 includes at least one first aperture and the main body 10 includes at least one through aperture and the second plate 30 includes at least one second aperture respectively. At least one fixer 80 has a first end secured to the at least one first aperture, a middle inserting through the through aperture, and a second end secured to the second aperture respectively. The at least one fixer 80 secures the main body 10 and the first and second plates 20 and 30 together. Furthermore, the first plate 20 includes a first hole and the torque-transmitting block 60 includes a through hole and the second plate 30 includes a second hole respectively. A fastener 90 has a first end secured to the first hole, a middle inserting through the through hole, and a second end secured to the second hole respectively.
In view of the foregoing, the two pawls 42 anchored to at least one of the first and second plates 20 and 30 enable the ratchet wrench of the present invention to withstand higher torque requirements. Contrary to a conventional ratchet wrench which has a main body made of metal, the main body 10 is made of rigid plastic, thereby saving the weight and the production cost of the main body 10 of a ratchet wrench. In order to reinforce the main body 10 and to enable the ratchet wrench to withstand higher torque requirements, the first and second plates 20 and 30 are made of rigid metal. In addition, each of the first and second plates 20 and 30 does not have a substantial thickness and is not bulky and weighty. Instead, each of the first and second plates 20 and 30 is in a form of a thin plate. The two pawls 42 are disposed in a mirror image relationship for transmitting the torque load without suffering stress concentration.
