Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2001-03-14
2003-04-08
Hail, III, Joseph J. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S063200
Reexamination Certificate
active
06543316
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a ratchet wrench for selectively applying torque to fasteners.
BACKGROUND OF THE INVENTION
Many types of ratchet wrenches are known in the art. Conventional wrenches typically include a wrench body, a torque receiving gear having gear teeth, a switch member and a gear engaging member in the form of a pawl having engaging teeth for intermeshing with the teeth on the torque receiving gear. Typically, the switch member in a conventional ratchet wrench is selectively movable between two positions. In each of these two position, the pawl is engaged with the gear teeth such that the wrench in one direction rotates the gear to apply torque to a fastener and rotating the wrench in the opposite direction causes the pawl to ride over the gear teeth in a ratcheting manner.
U.S. Pat. No. 5,533,427 discloses a ratchet wrench with an arcuate pawl. The arcuate shape of the pawl enables most or all of the teeth to be engaged with the gear teeth. The pawl is pivotally mounted on the upright free end of a torsion spring. The spring biases the pawl into engagement with the gear so as to provide a ratcheting action on the wrench's return stroke. As the switch is moved between positions, the upright free end of the torsion spring swings and moves the pawl to its opposite position for reverse driving. One drawback of this design, however, is that if the pawl is slightly stuck or jammed, movement of the switch may simply deflect the spring without moving the pawl.
Another shortcoming of this type of wrench is that the switch member is not sufficiently secured in either switch position during ratcheting. For example, in the '427 patent, a ball and spring are retained in a bore that is formed within the wrench body and the switch member has two detents formed therein. The spring biases the ball into a respective one of these detents in the switch member to retain the switch member in its associated switching position, and hence retains the pawl in its associated reversing position. However, in this configuration, the switch may having a tendency to move from one switch position to the other switch position during ratcheting, especially if accidentally bumped in that direction. As a result, during use of the wrench, users may have to hold the switch, for example, with their thumb or finger, tape or some other securing means, or ratchet the wrench slower to prevent undesired switch movement. The undesired switch movement can lead to a more difficult and more time-consuming ratcheting operation.
SUMMARY OF THE INVENTION
To address the problems realized with prior art wrenches, one aspect of the present invention provides a ratchet wrench for selectively applying torque to fasteners. The ratchet wrench comprises a wrench body providing (a) an elongated manually engageable handle configured for manual grasping thereof and (b) a ratchet head provided on the handle. The wrench body further provides spaced apart first and second engaging member abutment surfaces.
A torque receiving gear is mounted for rotation about a gear axis relative to the ratchet head with the torque receiving gear providing a plurality of gear teeth provided about the gear axis in a circular arrangement. The torque receiving gear is constructed and arranged to be removably coupled to a rotatable fastener in torque transmitting relation such that torque applied to the torque receiving gear is transmitted to the fastener removably coupled therewith to affect rotation of the fastener.
A switch member is accessible from an exterior of the wrench body. The switch member is selectively movable between a first switch position and a second switch position. A gear engaging member has a set of engaging teeth provided in an arcuate and concave arrangement substantially complementary to the circular arrangement of the gear teeth. The engaging teeth are configured to be engaged with the gear teeth in intermeshed relation.
A mounting element mounts the gear engaging member to the switch element. The gear engaging member is pivotally mounted to the mounting element such that selective movement of the switch member into the first position thereof moves the gear engaging member into a first ratcheting position and selective movement of the switch member into the second position thereof moves the gear engaging member into a second ratcheting position angularly spaced from the first ratcheting position with respect to the gear axis. The pivotal mounting of the gear engaging member enables the gear engaging member to pivot relative to the mounting element as the gear engaging member moves between the first and second ratcheting positions thereof.
The gear engaging member is constructed and arranged such that, when the torque receiving gear is removably coupled to a rotatable fastener in torque transmitting relation as aforesaid and the gear engaging member is in the first ratcheting position thereof, a force applied to the handle to affect a first torque applying movement abuts the gear engaging member against the first abutment surface. This forceably engages the engaging teeth of the gear engaging member with the gear teeth of the torque receiving gear in intermeshed relation to prevent rotation of the wrench body relative to the torque receiving gear so that the force applied to the handle to affect the first torque applying movement is transmitted through the gear engaging member and applied to the gear as a torque which is transmitted to the fastener to affect rotation thereof via the torque transmitting relation between the gear and the fastener. The gear engaging member also is constructed and arranged such that, when the torque receiving gear is removably coupled to a rotatable fastener in torque transmitting relation as aforesaid and the gear engaging member is in the second ratcheting position thereof, a force applied to the handle to affect a second torque applying movement abuts the gear engaging member against the second abutment surface. This forceably engages the engaging teeth of the gear engaging member with the gear teeth of the torque receiving gear to prevent rotation of the wrench body relative to the torque receiving gear so that the force applied to the handle to affect the second torque applying movement is transmitted through the gear engaging member and applied to the gear as a torque which is transmitted to the fastener to affect rotation thereof via the torque transmitting relation between the ratchet gear and the fastener.
A spring is engaged between the switch member and the mounting element to apply a biasing force to the gear engaging member through the mounting element. The spring and the mounting element are constructed and arranged such that, (a) when the gear engaging member is in the first ratcheting position, the spring is disposed in a first spring biasing position so that at least a component of the biasing force is directed circumferentially with respect to the gear axis and (b) when the gear engaging member is in the second ratcheting position, the spring is disposed in a second spring biasing position so that at least a component of the biasing force is directed circumferentially with respect to the gear axis.
The gear engaging member and the spring are constructed and arranged such that, when the torque receiving gear is removably coupled to a rotatable fastener in torque transmitting relation as aforesaid and the gear engaging member is in the first ratcheting position thereof, a force applied to the handle to affect a movement opposite the first torque applying movement rotates the wrench body relative to the torque receiving gear so that (a) the first abutment surface moves to a position wherein it allows the gear engaging member to move radially outward with respect to the rotational axis to permit the engaging teeth to disengage from the gear teeth, and (b) the engaging member moves generally circumferentially with respect to the gear axis with the engaging teeth thereof repeatedly interacting with the gear teeth in a ratcheting manner wherei
Daigle Odee P.
Loftin David
Redding Glenn
Savino Nick
Hail III Joseph J.
The Stanley Works
Thomas David B.
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