Patent Description:
The present invention relates to powered fastener drivers, and more specifically to pusher mechanisms for powered fastener drivers.

Powered fastener drivers are used for driving fasteners (e.g., nails, tacks, staples, etc.) into a workpiece. Such fastener drivers typically include a magazine in which the fasteners are stored and a pusher mechanism for individually transferring fasteners from the magazine to a fastener driving channel, where the fastener is impacted by a driver blade during a fastener driving operation.

According to its abstract, <CIT> describes a fastener driver that includes a drive blade movable from a retracted position to a driven position for driving a fastener into a workpiece and a gas spring mechanism for driving the drive blade from the retracted position to the driven position. The gas spring mechanism includes a piston movable between a retracted position and a driven position. The fastener driver further includes a first return mechanism for moving the drive blade from the driven position toward the retracted position, and a second return mechanism for moving the piston from the driven position toward the retracted position.

According to its abstract, <CIT> relates to an advance and release mechanism for strips of a screwdriver assembly that sequentially drives fasteners retained in a holding strip securing a plurality of fasteners in a row. The apparatus has a slide body with a lateral slot and an intersecting vertical bore. The lateral slot has a uniform transverse cross-section configured to slidingly receive the strip. A driver shaft including fastener driving bit means for engaging and driving a lead fastener in succession into said work piece is journalled and longitudinally slidably housed in the bore between an engaged position and a withdrawn position. Advance means are mounted to the body for incrementally forwardly advancing the fasteners of the strip within the lateral slot in succession and for aligning the lead fastener coaxially with the bore. The advance means includes: a shuttle housed in the body and reciprocally movable between an advanced position and retracted position; a pawl pivotably supported on the shuttle, the pawl having a strip pusher arm at a forward end thereof; pawl biasing means engaging the pawl and shuttle for urging the pusher arm into parallel engagement with the strip; and pawl release means engaging the pawl for manually disengaging the pawl from the strip, thereby permitting the screw strip to be removed from the lateral slot.

According to its abstract, <CIT> describes fastener-advancement systems that comprise a multiple lever and linkage mechanically operated system operatively connected to the driver blade member of the fastener driving tool, as well as electromechanically operated systems, for advancing a leading fastener of a collated strip of fasteners into the driver blade channel of the fastener-driving tool. In the electromechanically operated systems, push-type, pull-type, and rotary solenoid actuating members are utilized for moving the fastener-advancement feed pawl or claw member.

Described herein is a powered fastener driver including a housing, a nosepiece coupled to the housing and extending therefrom, a driver blade, a canister magazine coupled to the nosepiece, a pusher mechanism coupled to the nosepiece, and a cam. The driver blade is movable within the nosepiece between a ready position and a driven position. The nosepiece receives collated fasteners therein. The pusher mechanism individually transfers collated fasteners in the canister magazine to a driver channel in the nosepiece in which the driver blade is movable. The pusher mechanism includes a body coupled to the nosepiece, a feeder arm pivotably coupled to the body for movement therewith, and a lever pivotably coupled to the nosepiece about a pivot axis. The body relatively translates with the nosepiece. The lever has a first end that is engageable with the body for imparting reciprocating translation to the body relative to the nosepiece in response to pivoting movement of the lever in opposite directions about the pivot axis. The cam is engaged with a second end of the lever for imparting pivoting movement to the lever. The feeder arm is engageable with individual fasteners in the nosepiece for sequentially pushing the fasteners into the driver channel in response to reciprocation of the body relative to the nosepiece.

Also described herein is a powered fastener driver including a housing, a motor positioned in the housing, a nosepiece coupled to the housing and extending therefrom, a driver blade, a canister magazine coupled to the nosepiece, a lifting mechanism positioned within the housing, a pusher mechanism coupled to the nosepiece, a cam, and a gear train. The driver blade is movable within the nosepiece between a ready position and a driven position. The nosepiece receives collated fasteners from the canister magazine. The lifting mechanism is operable to move the driver blade from the driven position toward the ready position. The pusher mechanism individually transfers collated fasteners in the canister magazine to a driver channel in the nosepiece in which the driver blade is movable. The pusher mechanism includes a body coupled to the nosepiece, a feeder arm pivotably coupled to the body for relative movement therewith, and a lever pivotably coupled to the nosepiece about a pivot axis. The body relatively translates with the nosepiece. The lever has a first end that is engageable with the body for translating the body relative to the nosepiece in response to pivoting movement of the lever in opposite directions about the pivot axis, and an opposite, second end. The cam is engages with a second end of the lever. The gear train is operable to receive torque from the motor and distribute torque to the lifting mechanism and the cam, causing the cam to rotate and impart pivoting movement to the lever, which translates the body of the pusher mechanism relative to the nosepiece. The feeder arm is engageable with individual fasteners in the nosepiece for sequentially pushing the fasteners into the driver channel in response to reciprocation of the body relative to the nosepiece. Also described herein is a powered fastener driver including a housing, a nosepiece coupled to the housing and extending therefrom, a driver blade, a canister magazine coupled to the nosepiece, and a pusher mechanism coupled to the nosepiece. The driver blade is movable within the nosepiece between a ready position and a driven position. The nosepiece receives collated fasteners from the canister magazine. The pusher mechanism individually transfers collated fasteners in the canister magazine to a driver channel in the nosepiece in which the driver blade is movable. The pusher mechanism includes a body that is slidably coupled to the nosepiece, a feeder arm pivotably coupled to the body for movement therewith, and a solenoid. The body relatively translates with the nosepiece. The solenoid includes a solenoid housing and a plunger extending therefrom. The plunger is coupled to the body for imparting reciprocating translation to the body in response to activation and deactivation of the solenoid. The canister includes a mount portion to which the solenoid housing is coupled.

Additional features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

With reference to <FIG> and <FIG>, a gas spring-powered fastener driver <NUM> is operable to drive fasteners (e.g., nails) held within a canister magazine <NUM> into a workpiece. The fastener driver <NUM> includes a housing <NUM>, a cylinder <NUM> positioned within the housing <NUM>, and a moveable piston <NUM> positioned within the cylinder <NUM>. The fastener driver <NUM> further includes a driver blade <NUM> that is attached to the piston <NUM> and moveable therewith. The fastener driver <NUM> does not require an external source of air pressure, but rather includes a storage chamber cylinder <NUM> of pressurized gas in fluid communication with the cylinder <NUM>. In the illustrated embodiment, the cylinder <NUM> and moveable piston <NUM> are positioned within the storage chamber cylinder <NUM>.

With reference to <FIG>, the cylinder <NUM> and the driver blade <NUM> define a driving axis <NUM>, and during a driving cycle the driver blade <NUM> and piston <NUM> are moveable between a ready position (i.e., top dead center) and a driven position (i.e., bottom dead center). The fastener driver <NUM> further includes a lifting mechanism <NUM>, which is powered by a motor <NUM>, and which is operable to move the driver blade <NUM> from the driven position to the ready position.

In operation, the lifting mechanism <NUM> drives the piston <NUM> and the driver blade <NUM> to the ready position by energizing the motor <NUM>. As the piston <NUM> and the driver blade <NUM> are driven to the ready position, the gas above the piston <NUM> and the gas within the storage chamber cylinder <NUM> is compressed. Once in the ready position, the piston <NUM> and the driver blade <NUM> are held in position until released by user activation of a trigger <NUM>. When released, the compressed gas above the piston <NUM> and within the storage chamber <NUM> drives the piston <NUM> and the driver blade <NUM> to the driven position, thereby driving a fastener into a workpiece. The illustrated fastener driver <NUM> therefore operates on a gas spring principle utilizing the lifting assembly <NUM> and the piston <NUM> to further compress the gas within the cylinder <NUM> and the storage chamber cylinder <NUM>.

The canister magazine <NUM> includes collated fasteners <NUM> arranged in a coil. The magazine <NUM> is coupled to a nosepiece <NUM> in which the fasteners <NUM> are received (<FIG>). The fasteners <NUM> are sequentially transferred or loaded from the magazine <NUM> to a driver channel <NUM> in the nosepiece <NUM> by a pusher mechanism <NUM>. After the fastener <NUM> is inserted into the driver channel <NUM>, the driver blade <NUM> is movable within the driver channel <NUM> to discharge the fastener <NUM> into a workpiece.

With reference to <FIG> and <FIG>, the pusher mechanism <NUM> is driven in sync with the lifting mechanism <NUM> by a gear train <NUM> coupled to a transmission output shaft <NUM> and a cam <NUM> that receives torque from the gear train <NUM>, causing the cam <NUM> to rotate in unison with the lifting mechanism <NUM>. The gear train <NUM> consists of a first gear set <NUM> on the nosepiece <NUM> are received. The motion of the sliding body <NUM> is constrained to reciprocating linear movement in the direction of arrows A1, A2 (shown in <FIG>) that are parallel with the guide rails <NUM> relative to the magazine <NUM>.

The pusher mechanism <NUM> further includes a feeder arm <NUM> that is pivotably coupled to the sliding body <NUM> about a pivot axis <NUM> that is perpendicular to the direction of movement of the sliding body <NUM> along arrows A1, A2. Because the feeder arm <NUM> is supported upon the sliding body <NUM>, the feeder arm <NUM> reciprocates with the sliding body <NUM> in the direction of arrows A1, A2 in response to reciprocating pivoting movement of the lever <NUM>.

Prior to initiation of a firing cycle, a forward-most fastener <NUM> is positioned in the driver channel <NUM>, the sliding body <NUM> is located in a forward-most position relative to the nosepiece <NUM>, and the feeder arm <NUM> is pivoted to an inboard position to thereby receive one of the fasteners <NUM> behind the forward-most fastener <NUM> in aligned notches <NUM> in the feeder arm <NUM> (<FIG> and <FIG>). The forward-most position of the sliding body <NUM> coincides with the roller <NUM> being in contact with a valley <NUM> on the cam <NUM> (shown in <FIG>).

With reference to <FIG> and <FIG>, check pawls <NUM> are pivotably coupled to a shaft <NUM> carried on a nosepiece access door <NUM>, which is pivotably coupled to the nosepiece <NUM>. Each check pawl <NUM> includes a finger <NUM> that is in contact with the fasteners <NUM>. Springs (<FIG>) bias the respective check pawls <NUM> toward the fasteners <NUM> to maintain the fingers <NUM> in contact with the fasteners <NUM> as the fasteners <NUM> are advanced toward the nosepiece <NUM>. In operation, as the feeder arm <NUM> is retracted in the direction A1 (<FIG>), the fingers <NUM> of the respective check pawls <NUM> remain engaged with one of the collated fasteners <NUM> while the feeder arm <NUM> pivots around the same fastener <NUM>. After clearing the fastener <NUM>, the feeder arm <NUM> pivots toward an inboard position and behind the fastener <NUM> (<FIG>). As the feeder arm <NUM> moves the fastener <NUM> to the driver channel <NUM>, the check pawls <NUM> are biased away from the fasteners <NUM> to allow the collated fasteners <NUM> to advance (<FIG>). The springs biasing the respective check pawls <NUM> then rebound, positioning the check pawls <NUM> between the next two fasteners <NUM> in the sequence, preventing backwards movement of the collated fasteners <NUM> toward the canister magazine <NUM> (<FIG>).

When a firing cycle is initiated (e.g., by a user pulling a trigger <NUM> of the fastener driver <NUM>), the motor <NUM> is activated to rotate the lifting mechanism <NUM>, which releases the driver blade <NUM>, permitting the gas in the storage chamber cylinder <NUM> to expand and push the piston <NUM> downward into the cylinder <NUM>. Prior to the piston <NUM> reaching the bottom dead center position in the cylinder <NUM>, the driver blade <NUM> impacts the fastener <NUM> in the driver channel <NUM>, discharging the fastener <NUM> from the nosepiece <NUM> and into the workpiece. During this time, the lifting mechanism <NUM> continues to rotate (i. e, by the motor <NUM> providing torque to the transmission output shaft <NUM>), returning the piston <NUM> and driver blade <NUM> to the ready position in the cylinder <NUM>. Simultaneously, the rotating transmission output shaft <NUM> and gear train <NUM> rotates the cam <NUM>.

The cam <NUM> rotates nearly <NUM> degrees, causing the roller <NUM> to follow the cam <NUM> as the cam surface transitions from the valley <NUM> to a peak <NUM> (<FIG>, <FIG>, and <FIG>), imparting pivoting movement to the lever <NUM> about the axis <NUM> in a direction opposite the arrow A0 (<FIG>). As the lever <NUM> pivots, the fork <NUM> pushes the protruding pin <NUM> of the sliding body <NUM>, converting the pivoting motion of the lever <NUM> to linear motion of the body <NUM> (<FIG>). As the body <NUM> slides away from the driver channel <NUM> in the direction of A1, the feeder arm <NUM> pivots to clear the next fastener in the sequence (<FIG>). At this time, the check pawls <NUM> remain engaged with one of the fasteners <NUM>, preventing the collated fasteners <NUM> from being driven rearward toward the canister magazine <NUM>. When the body <NUM> is at a position farthest from the driver channel <NUM> (i.e., when the body <NUM> changes the direction of translation from A1 to A2), the springs biases the feeder arm <NUM> behind the next fastener <NUM> in the sequence (<FIG>). Then, continued rotation of the cam <NUM> causes the roller <NUM> to transition from the peak <NUM> back to the valley <NUM>, allowing the torsion spring <NUM> acting on the lever <NUM> to rebound, pivoting the lever <NUM> in the direction of arrow A0 and moving the fork <NUM> and, thus, the body <NUM> forward. Forward motion of the body <NUM> toward the driver channel <NUM> in the direction of A2 moves the feeder arm <NUM> forward (<FIG>) and thus, pushes the collated fasteners <NUM> forward, and one of which into the driver channel 54A (<FIG>). As such, pivoting movement of the lever <NUM> in the direction of arrow A0 and then a direction opposite arrow A0 as described above defines a complete reloading cycle of one of the collated fasteners <NUM> into the driver channel <NUM>.

In an alternative embodiment of the fastener driver (not shown), the pusher mechanism <NUM> may be actuated by the impact of the driver blade <NUM> upon reaching the driven position. As the driver blade <NUM> moves from the ready position to the driven position, the driver blade <NUM> may either directly contact or indirectly contact (e.g., via an arm or linkage, not shown) the roller <NUM>, which imparts pivotal motion to the lever <NUM>. As described above, the pivotal motion imparted on the lever <NUM> displaces the sliding body <NUM> and feeder arm <NUM> along arrow A2, allowing the feeder arm <NUM> to pick up the next fastener <NUM> in the collated strip. Thereafter, the torsion spring acting on the lever <NUM> rebounds, pivoting the lever <NUM> in the direction of arrow A0 and displacing the sliding body <NUM> and feeder arm <NUM> in the direction of arrow A1 (<FIG>), positioning another fastener <NUM> in the driver channel <NUM> as described above.

In another alternative embodiment of the fastener driver (not shown), the pusher mechanism <NUM> may be actuated by the impact of the piston <NUM> on a bumper <NUM> (<FIG>) within the cylinder <NUM> for stopping the driver blade <NUM> in the driven position. The bumper <NUM> may either directly contact or indirectly contact (e.g., via an arm or linkage, not shown) the roller <NUM>, which imparts pivotal motion to the lever <NUM>. As described above, the pivotal motion imparted on the lever <NUM> displaces the sliding body <NUM> and feeder arm <NUM> along arrow A2, allowing the feeder arm <NUM> to pick up the next fastener <NUM> in the collated strip. Thereafter, the torsion spring acting on the lever <NUM> rebounds, pivoting the lever <NUM> in the direction of arrow A0 and displacing the sliding body <NUM> and feeder arm <NUM> in the direction of arrow A1 (<FIG>), positioning another fastener <NUM> in the driver channel <NUM> as described above.

<FIG> illustrates a gas spring-powered fastener driver 10A including another embodiment of a pusher mechanism 58A. The driver 10A is similar to the driver <NUM> described above with reference to <FIG>. Accordingly, features and elements of the driver 10A corresponding with features and elements of the driver <NUM> are given like reference numbers followed by the letter 'A. ' In addition, the following description focuses primarily on differences between the pusher mechanism 58A and the pusher mechanism <NUM>.

Similar to the driver <NUM>, the driver 10A includes a lifting mechanism 42A that returns a piston 22A and a driver blade 26A to the ready position by energizing a motor 46A. The pusher mechanism 58A differs from the pusher mechanism <NUM> in that the pusher mechanism 58A is not driven in sync with the lifting mechanism 42A by a gear train. Rather, the pusher mechanism 58A includes a solenoid <NUM> (<FIG>) coupled to the canister magazine 14A via a bracket <NUM> clamping a solenoid housing <NUM> to a mount portion <NUM> of the canister magazine 14A. The bracket <NUM> is fastened to the mount portion <NUM> of the canister 14A via a plurality of fasteners <NUM> or the like. A plunger <NUM> is disposed within the solenoid housing <NUM> and is movable between an extended position and a retracted position. In the extended position, a plunger spring <NUM> disposed around the plunger <NUM> biases the plunger <NUM> from the solenoid housing <NUM>. In the retracted position, the solenoid <NUM> is engaged, meaning an electromagnet attracts the plunger <NUM> within the solenoid housing <NUM>, against the bias of the spring <NUM>. A plate <NUM> is coupled to an end of the plunger <NUM> such that movement of the plunger <NUM> imparts reciprocating movement to the plate <NUM>. The pusher mechanism 58A further includes a sliding body 90A, which has an opening <NUM> for receiving an end of the plate <NUM> to secure the body 90A to the plate <NUM>. The motion of the sliding body 90A is constrained to reciprocating linear movement in the direction of arrows A1, A2 relative to the magazine 14A by engaged guide rails <NUM> and grooves <NUM>. A feeder arm 94A is pivotably coupled to the sliding body 90A about a pivot axis 99A that is perpendicular to the direction of movement of the sliding body 90A along arrows A1, A2 and is biased toward the fasteners <NUM> by compression springs <NUM>. Because the feeder arm 94A is supported upon the sliding body 90A, the feeder arm 94A reciprocates with the sliding body 90A in the direction of arrows A1, A2 in response to reciprocating movement of the plunger <NUM>.

In operation, after the driver blade 26A strikes the fastener <NUM>, the solenoid <NUM> is activated, retracting the plunger <NUM> and, thus, sliding the body 90A away from the driver channel 54A in the direction of A1, allowing the feeder arm to pivot to clear the next fastener <NUM> in the sequence. When the plunger <NUM> is completely retracted, the body 90A is at a position farthest from the driver channel 54A, allowing the springs to bias the feeder arm behind the next fastener <NUM> in the sequence. At this time, the solenoid <NUM> is deactivated, causing the plunger spring <NUM> to bias the plunger <NUM> outward. The outward motion of the plunger <NUM> moves the body 90A and, in turn, the feeder arm toward the driver channel 54A. When the plunger <NUM> is completely extended, a forward most fastener <NUM> is delivered to the driver channel 54A by the feeder arm.

The system that determines when the solenoid <NUM> is energized is an open feedback system, meaning the system does not know the location of the lifting mechanism 42A. Instead, once a user pulls the trigger <NUM>, the system operates based on predetermined timing to activate and deactivate the solenoid <NUM>.

Claim 1:
A powered fastener driver (<NUM>) comprising:
a housing (<NUM>);
a nosepiece (<NUM>) coupled to the housing and extending therefrom;
a driver blade (<NUM>) movable within the nosepiece between a ready position and a driven position;
a canister magazine (<NUM>) coupled to the nosepiece in which collated fasteners (<NUM>) are receivable;
a lifting mechanism (<NUM>) operable to move the driver blade from the driven position toward the ready position;
a pusher mechanism (<NUM>) coupled to the nosepiece for individually transferring collated fasteners in the canister magazine to a driver channel (<NUM>) in the nosepiece in which the driver blade is movable, characterised in that the pusher mechanism further including
a body (<NUM>) coupled to the nosepiece for relative translation therewith,
a feeder arm (<NUM>) coupled to the body for movement therewith, and
a lever (<NUM>) pivotably coupled to the nosepiece about a pivot axis (<NUM>), the lever having a first end engageable with the body for imparting reciprocating translation to the body relative to the nosepiece in response to pivoting movement of the lever in opposite directions about the pivot axis;
a cam (<NUM>) with which a second end of the lever is engaged for imparting pivoting movement to the lever; and
a gear train (<NUM>) for providing torque to the lifting mechanism, causing the lifting mechanism to rotate, wherein the cam also receives torque from the gear train, causing the cam to rotate in unison with the lifting mechanism;
wherein the feeder arm is engageable with individual fasteners in the nosepiece for sequentially pushing the fasteners into the driver channel in response to reciprocation of the body relative to the nosepiece.