Patent Application
20200269392
The present invention relates generally to ratchet wrenches. More particularly, the present invention relates to ratchet wrenches having a dual pawl with a spring bias member.
Ratchet wrenches are common hand tools used to apply torque to work pieces. Ratchet wrenches include a pawl mechanism that allows the tool to torque a work piece in a first rotational direction by rotating the tool in that rotational direction, and then return the tool to its original position by rotating the tool in a second rotational direction opposite the first rotational direction. The pawl mechanism engages a drive gear to “lock” the gear to impart the torque in the first rotational direction, but allows the pawl to slip relative to the drive gear in the second rotational direction. A reversing lever can reverse which of the first and second rotational directions applies torque to the work piece, for example, if the work piece is left hand threaded or if the user is using the tool to remove the work piece from its position.
Two pawl ratchet wrenches require the pawl to disengage the gear in order to ratchet. Typically, this requires the gear to rotate an angle equal to about two to three times the tooth pitch of the pawl teeth. Prior ratchet wrenches attempt to solve this problem by including a bias member that urges the pawl into engagement with the drive gear, but this arrangement requires a spacer for the spring to pivot and sit within.
The present invention broadly comprises a dual pawl ratchet tool with a leaf spring bias member. The leaf spring includes two bias portions coupled together by a fulcrum. The fulcrum can be placed in an indent of the pawl pocket to maintain structural stability while applying a bias force against the engaged pawl. In doing so, the bias member reduces the amount of lost motion incurred during the ratcheting operation.
In particular, the present invention broadly comprises a tool having a handle, a head extending from the handle and including a cavity defined therein and an indent within the pocket, and a drive gear disposed within the pocket and adapted to provide torque to work pieces. The tool can further include first and second pawls adapted to engage the drive gear, a reversing lever coupled to the first and second pawls that causes either the first or second pawl to engage the drive gear depending on a position of the reversing lever, and a bias member having first and second bias portions coupled together by a fulcrum, the first and second bias members respectively applying bias to the first and second pawls, depending on the position of the reversing lever, wherein the fulcrum is positioned within the indent. When the first pawl engages the drive gear, the first bias member biases the first pawl into engagement with the drive gear, and when the second pawl engages the drive gear, the second bias member biases the second pawl into engagement with the drive gear.
Further disclosed is a tool including a handle, a head extending from the handle and including a pocket defined therein and an indent within the pocket, and a drive gear disposed within the pocket and adapted to provide torque to work pieces. The tool can further include first and second pawls adapted to meshingly engage the drive gear, and a bias member having first and second bias portions coupled together by a fulcrum positioned within the indent. When the first pawl engages the drive gear, the first bias member biases the first pawl into engagement with the drive gear, and when the second pawl engages the drive gear, the second bias member biases the second pawl into engagement with the drive gear.
For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.
While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated. As used herein, the term “present invention” is not intended to limit the scope of the claimed invention and is instead a term used to discuss exemplary embodiments of the invention for explanatory purposes only.
The present invention broadly comprises a tool with multiple pawls that are biased into engagement with gear teeth circumferentially disposed on a drive gear by a bias member. The bias member can be a leaf spring that includes two bias portions that are coupled to one another by a fulcrum. The tool can include a pawl pocket that defines an indent where the fulcrum can be disposed when assembled to maintain structural stability of the bias member while the bias member applies a bias force against the pawl to be engaged with the gear teeth. In doing so, the bias member reduces the amount of lost motion incurred during a ratcheting operation.
As shown in
As shown, the tool 100 can include a reversing lever 140 that a user can turn to selectively cause the tool 100 to operate in either of the clockwise or counterclockwise directions. The reversing lever 140 can include a knob 142 that a user can grip to select the desired rotational direction that the tool 100 will apply torque in. The reversing lever 140 can also include hooks 145 that engage pawls 152, 153. For example, depending on how the reversing lever 140 is rotated, the hooks 145 will engage one of the pawls 152, 153 and cause the engaging pawl 152 to then engage the drive gear 155.
As shown in
The tool 100 includes a type of ratchet known as a dual-pawl ratchet wrench allowing a user to selectively determine a torque direction. More specifically, the first and second pawls 152, 153 can be selectively engaged with the drive gear 155, whereas the drive gear 155 can be operatively engaged with the work piece to apply torque to the work piece. When the first pawl 152 is engaged with the drive gear 155, torque drive is permitted with rotation of the tool 100 in a first rotational drive direction while slippage occurs with rotation of the tool 100 in a second rotational direction opposite the first rotational direction. Conversely, when the second pawl 153 is engaged with the drive gear 155, the first pawl 152 moves out of engagement with the drive gear 155, and torque drive is permitted with rotation of the tool 100 in the second rotational direction while slippage occurs in the first rotational direction.
As described, the reversing lever 140 is configured to select one of the pawls 152, 153 to thereby select a rotational direction in which the tool 100 can apply torque. For example, one of the hooks 145 of the reversing lever 140 can engage one of the pawls 152, 153 and cause the engaging pawl 152 to then engage the drive gear 155. In doing so, the reversing lever 140 will cause the other of the pawls 153 to disengage from the drive gear 155. The end result is that the engaging pawl 152 will cause its teeth to engage with the teeth of the drive gear 155, allowing the engaging pawl 152 to slip when the handle 110 is rotated in a first rotational direction (as shown in
As discussed above, the pawls 152, 153 can incur lost motion when engaging the drive gear 155 unless the engaging pawl 152 is biased into engagement with the gear teeth of the drive gear 155. For this reason, at least some of the presently disclosed embodiments implement the bias member 120 to bias the engaging pawl 152 into engagement with the gear teeth of the drive gear 155. For example, the first bias portion 122 can engage the first pawl 152 when the first pawl 152 is the engaging pawl, and the second bias portion 123 can engage the second pawl 153 when the second pawl 153 is the engaging pawl.
As shown in
The ball detent mechanism 135 is positioned within the pocket 115 of the head 105 and is biased in an upwardly direction, towards the bottom of the reversing lever 140. The reversing lever 140 can include partially-spherical divots that receive the ball 125 when the reversing lever 140 is rotated a permissible amount either clockwise or counterclockwise. The ball 125 can therefore provide a tactile indication to the user that the reversing lever 140 has reached the desired rotational engagement direction, and further detain the reversing lever 140 in the desired position. As shown in
As used herein, the term “coupled” and its functional equivalents are not intended to necessarily be limited to direct, mechanical coupling of two or more components. Instead, the term “coupled” and its functional equivalents are intended to mean any direct or indirect mechanical, electrical, or chemical connection between two or more objects, features, work pieces, and/or environmental matter. “Coupled” is also intended to mean, in some examples, one object being integral with another object.
The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the inventors' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
