Patent Description:
The present invention relates to power tools, and more specifically to mounts on power tools that are configured to receive a lanyard to support the power tool.

Power tools carried around and used by operators at worksites are sometimes dropped, which can damage the power tool. Sometimes power tools include mounts for receiving a lanyard that can be attached to a user's work belt, such that if the power tool is dropped, the power tool does not hit the ground.

According to its abstract, <CIT> describes a power tool and a rotary impact tool capable of suppressing transmission of vibration to a circuit board and so on from a drive portion connecting to a motor as a vibration generation source. An impact wrench includes a motor housing which houses a motor or a grip housing, a battery holding housing connecting to the motor housing or the grip housing through an elastic body and a control circuit board housed in the battery holding housing for controlling the motor.

According to its abstract, <CIT> describes a power tool that includes a motor unit, a main body portion, a grip portion and a female thread part. The main body portion accommodates the motor unit therein. The grip portion extends from the main body portion. The female thread part is retained to the main body portion. The female thread part includes a female thread configured and arranged to engage with a male thread of a male thread part of a power tool accessory member.

According to its abstract, <CIT> describes an electric power tool that includes a body part for outputting a rotational force at one end thereof, a grip part provided to extend from the body part in an intersecting relationship with the body part, and a suspension link provided at the other end of the body part for hanging the body part. the suspension link is configured to ensure that, if the body part is suspended from the suspension link using the suspension link as a pivot point, the electric power tool is kept by a weight balance in a horizontal posture in which the extension direction of the grip part is substantially orthogonal to the vertical direction or an inclined horizontal posture in which the joint portion of the body part and the grip part is positioned at the upper side.

According to its opening statement, <CIT> describes a bracket holder for a hand tool with a flat housing body.

According to its abstract, <CIT> describes a suspension device that includes a ring for hanging the power tool and a ring retaining member provided at an upper part of a housing of the power tool. The housing has a grip at a lower part thereof. The ring retaining member is configured such that the ring is movable between a standing position and a lying position and that the ring is retainable in the standing position.

Aspects of the present invention are defined by the appended independent claim.

Described herein by way of example is a power tool supportable by a lanyard. The power tool comprises a motor housing, a motor arranged in the motor housing, front housing, an output member extending from the front housing, a gear case, and a gear train arranged in the gear case. The gear train is configured to transfer torque from the motor to the output member. The power tool further comprises a first fastener securing the front housing to the motor housing, and a bracket fastened to one of the front housing, the motor housing, or the gear case by a second fastener that does not secure the front housing to the motor housing. The power tool further comprises a support member secured to the one of the front housing, the motor housing, or the gear case by the bracket. The support member is attachable to the lanyard.

Also described herein by way of example is a power tool supportable by a lanyard. The power tool comprises a motor housing, a motor arranged in the motor housing, a front housing, an output member extending from the front housing, a gear case having a mounting portion arranged between the front housing and the motor housing, and a gear train arranged in the gear case. The gear train is configured to transfer torque from the motor to the output member. The power tool further comprises a bracket coupled to the mounting portion and a support member secured to the mounting portion by the bracket. The support member is attachable to the lanyard.

Also described herein by way of example is an impact tool, corresponding to the power tool according to the invention, comprising a motor housing, a motor arranged in the motor housing, an impact housing corresponding to the front housing, an impact mechanism corresponding to the output member arranged in the impact housing, a gear case having a mounting portion arranged between the impact housing and the motor housing, and a gear train arranged in the gear case. The gear train is configured to transfer torque from the motor to the impact mechanism. The power tool further comprises a bracket fastened to the mounting portion and a support member secured to the mounting portion by the bracket. The support member is attachable to the lanyard.

<FIG> and <FIG> illustrate a power tool in the form of an impact tool or impact wrench <NUM>. The impact wrench <NUM> includes a motor housing <NUM> housing an electric motor <NUM>, a gear case <NUM> at least partially housing a gear train <NUM>, a front or impact housing <NUM> housing an impact mechanism <NUM>, and an output member, such as a head <NUM> of an anvil <NUM>. The gear train <NUM> transfers torque from the motor <NUM> to the impact mechanism <NUM>, such that the impact mechanism <NUM> can transfer torque to the head <NUM>. The impact wrench <NUM> also includes a generally D-shaped handle <NUM> with a grip <NUM> that can be grasped by an operator operating the impact wrench <NUM>. A rubber boot <NUM> overlies a front end of the impact housing <NUM> to provide protection for the impact housing <NUM>. The impact wrench <NUM> further includes an end cap <NUM> coupled to a rear end of the motor housing <NUM>.

The impact wrench <NUM> has a battery pack <NUM> (<FIG>) removably coupled to a battery receptacle <NUM> (<FIG>) located at a bottom end of the handle <NUM>. The battery pack <NUM> is rechargeable and may have a Lithium-based chemistry (e.g., Lithium, Lithium-ion, etc.) or any other suitable chemistry. The motor <NUM> receives power from the battery pack <NUM> when the battery pack <NUM> is coupled to the battery receptacle <NUM>. The motor <NUM> has an output shaft <NUM> that is rotatable about an axis <NUM>. The impact wrench <NUM> also includes a trigger switch <NUM> provided in the handle <NUM> that selectively electrically connects the motor <NUM> and the battery pack <NUM> to provide DC power to the motor <NUM>.

The gear train <NUM> is coupled to the motor output shaft <NUM>, and the impact mechanism <NUM> is coupled to an output of the gear train <NUM>. The gear train <NUM> may be configured in any of a number of different ways to provide a speed reduction between the output shaft <NUM> and an input of the impact mechanism <NUM>. With reference to <FIG>, the illustrated gear train <NUM> includes a helical pinion <NUM> formed on the motor output shaft <NUM>, a plurality of helical planet gears <NUM> meshed with the helical pinion <NUM>, and a helical ring gear <NUM> meshed with the planet gears <NUM> and rotationally fixed within the gear case <NUM>. The planet gears <NUM> are mounted on a camshaft <NUM> of the impact mechanism <NUM> such that the camshaft <NUM> functions as a planet carrier. Accordingly, rotation of the output shaft <NUM> rotates the planet gears <NUM>, which then advance along the inner circumference of the ring gear <NUM> and thereby rotate the camshaft <NUM>. The output shaft <NUM> is rotatably supported by a first or forward bearing <NUM> and a second or rear bearing <NUM> that is supported by the end cap <NUM>.

The impact mechanism <NUM> of the impact wrench <NUM> will now be described with reference to <FIG>. The impact mechanism <NUM> includes the anvil <NUM> having the head <NUM>, which extends from the impact housing <NUM>. A socket can be coupled to the head <NUM> for performing work on a workpiece (e.g., a fastener). The impact mechanism <NUM> is configured to convert the continuous rotational force or torque provided by the motor <NUM> and gear train <NUM> to a striking rotational force or intermittent applications of torque to the anvil <NUM> when the reaction torque on the anvil <NUM> (e.g., due to engagement between the tool element and a fastener being worked upon) exceeds a certain threshold. In the illustrated embodiment of the impact wrench <NUM>, the impact mechanism <NUM> includes the camshaft <NUM>, a hammer <NUM> supported on and axially slidable relative to the camshaft <NUM>, and the anvil <NUM>.

The impact mechanism <NUM> further includes a spring <NUM> biasing the hammer <NUM> toward the front of the impact wrench <NUM> (i.e., toward the right in <FIG>). In other words, the spring <NUM> biases the hammer <NUM> in an axial direction toward the anvil <NUM>, along the axis <NUM>. A thrust bearing <NUM> and a thrust washer <NUM> are positioned between the spring <NUM> and the hammer <NUM>. The thrust bearing <NUM> and the thrust washer <NUM> allow for the spring <NUM> and the camshaft <NUM> to continue to rotate relative to the hammer <NUM> after each impact strike when lugs on the hammer <NUM> engage with corresponding anvil lugs <NUM> (<FIG>) and rotation of the hammer <NUM> momentarily stops.

The camshaft <NUM> further includes cam grooves <NUM> in which corresponding cam balls <NUM> are received (<FIG>). The cam balls <NUM> are in driving engagement with the hammer <NUM> such that movement of the cam balls <NUM> within the cam grooves <NUM> allows for relative axial movement of the hammer <NUM> along the camshaft <NUM> when the hammer lugs and the anvil lugs <NUM> are engaged, rotation of the anvil <NUM> is seized, and the camshaft <NUM> continues to rotate. With reference to <FIG> and <FIG>, the anvil <NUM> includes the head <NUM> at its distal end. In the illustrated embodiment, the head <NUM> has a generally square cross-sectional shape in a plane oriented transverse a rotational axis of the anvil <NUM> (i.e., the axis <NUM>).

With reference to <FIG>, the gear case <NUM> includes an upwardly-extending mounting portion <NUM> that is arranged between a portion <NUM> of the motor housing <NUM> and a portion <NUM> of the impact housing <NUM>. The mounting portion <NUM> includes a pair of mounting bores <NUM> extending through a mounting surface <NUM>. The mounting portion <NUM> protrudes radially through the motor housing <NUM> such that the bores <NUM> are exposed to the exterior of the impact wrench <NUM>. In some embodiments, the mounting surface <NUM> can be substantially flush with the motor housing <NUM>. In other words, the mounting surface <NUM> can be even with or <NUM> above or below of the top of the portion <NUM> of the motor housing <NUM>. In some embodiments, the mounting surface <NUM> can be substantially flush with the portion <NUM> of the impact housing <NUM>. In other words, the mounting surface <NUM> can be even with or <NUM> above or below the top of the portion <NUM> of the impact housing <NUM>. In some embodiments, the mounting surface <NUM> can be located above the portion <NUM> of the motor housing <NUM>. In some embodiments, the mounting surface <NUM> can be located above the portion <NUM> of the impact housing <NUM>. In some embodiments, the mounting surface <NUM> may be parallel or substantially parallel to the portion <NUM> of the motor housing <NUM>. In some embodiments, the mounting surface <NUM> may be parallel or substantially parallel to the portion <NUM> of the impact housing <NUM>.

As shown in <FIG>, <FIG>, <FIG>, and <FIG>, a bracket <NUM> can be removably coupled to the mounting portion <NUM> via a pair of fasteners <NUM> that extend through a pair of bracket bores <NUM> that are alignable with the mounting bores <NUM> of the mounting portion <NUM>. In some embodiments, the mounting portion <NUM> is formed of metal and the fasteners <NUM> are also formed of metal. In some embodiments, the bracket <NUM> is not formed via a stamping process and is instead formed from, e.g., a die casting process, thus making it thicker and less susceptible to being bent or deformed, giving it softer corners, and making it less likely to scratch workpieces. When the bracket <NUM> is coupled to the mounting portion <NUM>, the first fasteners <NUM> extend along a first plane P1 (<FIG>) and a recess <NUM> (<FIG>) is defined between the bracket <NUM> and the mounting portion <NUM>.

Before fastening the bracket <NUM> to the mounting portion <NUM>, a securing member such as ring <NUM> can be arranged within the recess <NUM>. The ring <NUM> is configured to receive a lanyard <NUM> (<FIG>) that is attached to, e.g., a user's belt at a jobsite, such that if the user drops the impact wrench <NUM>, the lanyard <NUM>, ring <NUM>, and bracket <NUM> will cooperate to prevent the impact wrench <NUM> from hitting the ground. The ring <NUM> is configured to pivot within the recess <NUM>, providing flexibility with how the lanyard <NUM> secures the impact wrench <NUM>. In some embodiments, the plane P1 intersects a center of gravity CG (<FIG>) of the impact wrench <NUM>, such that if the impact wrench <NUM> is suspended vertically from the lanyard, the axis <NUM> will be substantially parallel to the ground. As shown in <FIG>, at least a portion of the bracket <NUM> has a substantially arcuate cross-section. In the illustrated embodiment, the bracket <NUM> is mounted to the mounting portion <NUM> of the gear case <NUM>. However, in other embodiments, the bracket <NUM> can be mounted to either the impact housing <NUM> or the motor housing <NUM>.

As shown in <FIG>, the motor housing <NUM> has four motor housing bores <NUM>. As shown in <FIG>, the impact housing <NUM> has four impact housing bores <NUM>. As shown in <FIG>, the gear case <NUM> has four gear case bores <NUM>. As shown in <FIG> and <FIG>, four fasteners <NUM> extend respectively, in the following order, through each of the motor housing bores <NUM>, gear case bores <NUM>, and impact housing bores <NUM>, such that the fasteners <NUM> start through the motor housing bores <NUM> and terminate in the impact housing bores <NUM>. In this manner, the impact housing <NUM> is coupled to the motor housing <NUM> and the gear case <NUM> is secured (i.e., clamped) between the motor housing <NUM> and the impact housing <NUM>. As shown in <FIG>, the top pair of the fasteners <NUM> extend along a second plane P2 that is perpendicular to the first plane P1.

Because the bracket <NUM> is secured to the mounting portion <NUM> with only the fasteners <NUM>, removal of the fasteners <NUM> that join the impact housing <NUM> and gear case <NUM> to the motor housing <NUM> is not required to remove the bracket <NUM> from the mounting portion <NUM>. This arrangement thus affords the user greater convenience when removing the bracket <NUM> to service or remove the ring <NUM>. Also, because the bracket <NUM> is not secured to the impact wrench <NUM> via the fasteners <NUM>, the mounting bracket <NUM> is more easily shared across different tools having an arrangement of mounting bores that are similar to the arrangement of the mounting bores <NUM> of the mounting portion <NUM>.

In operation of the impact wrench <NUM>, a user depresses the trigger switch <NUM> to activate the motor <NUM>, which continuously drives the gear train <NUM> and the camshaft <NUM> via the output shaft <NUM>. As the camshaft <NUM> rotates, the cam balls <NUM> drive the hammer <NUM> to co-rotate with the camshaft <NUM>, and the hammer lugs engage, respectively, driven surfaces of the anvil lugs <NUM> to provide an impact and to rotatably drive the anvil <NUM> and the tool element. After each impact, the hammer <NUM> moves or slides rearward along the camshaft <NUM>, away from the anvil <NUM>, so that the hammer lugs disengage the anvil lugs <NUM>. The spring <NUM> stores some of the rearward energy of the hammer <NUM> to provide a return mechanism for the hammer <NUM>. After the hammer lugs disengage the respective anvil lugs <NUM>, the hammer <NUM> continues to rotate and moves or slides forwardly, toward the anvil <NUM>, as the spring <NUM> releases its stored energy, until the drive surfaces of the hammer lugs re-engage the driven surfaces of the anvil lugs <NUM> to cause another impact.

Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope of the claims.

Claim 1:
A power tool (<NUM>) supportable by a lanyard (<NUM>), the power tool comprising:
a motor housing (<NUM>);
a motor (<NUM>) arranged in the motor housing;
a front housing (<NUM>);
an output member (<NUM>) extending from the front housing;
a gear case (<NUM>);
a gear train (<NUM>) arranged in the gear case, the gear train configured to transfer torque from the motor to the output member;
a first fastener (<NUM>) securing the front housing to the motor housing;
a bracket (<NUM>) fastened to the gear case by a second fastener (<NUM>) that does not secure the front housing to the motor housing; and
a support member (<NUM>) secured to the gear case by the bracket, the support member being attachable to the lanyard.