Patent Application
20120085806
The present invention is related to a dry fire lockout with a bypass for a fastener driving device.
Actuating a fastener driving device, such as a pneumatic nail gun, without a fastener in the device may leave undesirable driver marks on a work piece. A dry fire lockout is generally designed to prevent a user from accidentally actuating the fastener driving device by preventing a contact safety trip from being actuated when there are no or only a few fasteners remaining in the fastener driving device. Because the contact safety trip typically cannot move when the dry fire lockout is in place, there is a potential to damage the contact safety trip in the event the fastener driving device is accidentally dropped.
It is desirable to provide a fastener driving device with a dry fire lockout that may be bypassed in the sense that a portion of the contact safety trip may move in the event the device is dropped to protect the contact safety trip, while still preventing accidental actuation of the fastener driving device.
According to one aspect of the invention, there is provided a fastener driving device that includes a housing having an engine receiving portion, and a drive engine located in the engine receiving portion. The drive engine includes a cylinder and a piston reciprocally mounted within the cylinder. The piston includes a driver configured to move along a drive axis to drive a fastener during a drive stroke. A nose assembly is operatively connected to the housing. The nose assembly includes a drive track aligned with the drive axis. A magazine is constructed and arranged to feed successive leading fasteners from a supply of fasteners into the drive track. A pusher assembly includes a pusher configured to push the supply of fasteners towards the drive track, and a lifter that includes a dry fire lockout portion. A trigger is configured to operate the drive engine. The fastener driving device also includes a contact trip assembly that includes a lower contact arm including a first end configured to contact a work piece, and an upper contact arm including a first end operatively connected to the lower contact arm, and a second end configured to enable the trigger to operate the drive engine. The contact trip assembly also includes a link movably mounted to the first end of the upper contact arm and interconnected with the lower contact arm when the link is in a first orientation. The link includes a dry fire lockout portion, and a biasing member positioned between the link and the upper contact arm. The biasing member is configured to bias the link in the first orientation so that the link is interconnected with the lower contact arm to operatively connect the link and the lower contact arm. The dry fire lockout portion of the lifter is configured to engage the dry fire lockout portion of the link, when the supply of fasteners is less than a predetermined number of fasteners, and move the link against the bias of the biasing member to a second orientation in which the link is not interconnected with the lower contact arm.
According to another aspect of the invention, there is provided a dry fire lockout assembly for a fastener driving device. The dry fire lockout assembly includes a lifter that includes a dry fire lockout portion, and a contact trip assembly that includes a lower contact arm comprising a first end configured to contact a work piece, and an upper contact arm including a first end operatively connected to the lower contact arm, and a second end configured to enable a trigger to operate a drive engine of the fastener driving device. The contact trip assembly also includes a link movably mounted to the first end of the upper contact arm and interconnected with the lower contact arm when the link is in a first orientation. The link includes a dry fire lockout portion. The contact trip assembly also includes a biasing member positioned between the link and the upper contact arm. The biasing member is configured to bias the link in the first orientation so that the link is interconnected with the lower contact arm to operatively connect the link and the lower contact arm. The dry fire lockout portion of the lifter is configured to engage the dry fire lockout portion of the link, when a supply of fasteners in a magazine of the fastener driving device is less than a predetermined number of fasteners, and move the link against the bias of the biasing member to a second orientation in which the link is not interconnected with the lower contact arm.
These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one embodiment, the structural components illustrated herein are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not a limitation of the invention. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
Features of the fastener driving device in accordance with one embodiment are shown in the drawings, in which like reference numerals designate like elements. The drawings form part of this original disclosure in which:
Referring now more particularly to the drawings, there is shown in
Specifically, the pneumatically powered fastener driving device 10 shown in
The reservoir 18 communicates with a manually operable trigger valve assembly 22, which controls the communication of the reservoir to a pilot pressure chamber 24 of a main valve assembly 26. The main valve assembly 26 is housed within a cap assembly 28, fixed to the top of a main housing section 30, that is integral with and extending generally perpendicular to the handle section 16, both of which form parts of the portable housing assembly 14.
Mounted within the main housing section 30 is a cylinder 32, an upper end of which cooperates with the main valve assembly 26 to enable the main valve assembly 26 to function in the usual fashion when in an inoperative position, wherein the pilot pressure chamber 24, under the control of trigger valve assembly 22 in its inoperative position, is communicated with the reservoir 18. When in its inoperative position, the main valve assembly 26 also functions to communicate the open upper end of the cylinder 32 with atmosphere through the cap assembly 28.
When the trigger valve assembly 22 is manually moved from its inoperative position into an operative position, the pilot pressure chamber 24 is shut off from communication with the reservoir 18 and communicated with atmosphere. The pressure from the reservoir 18 then acts upon the main valve assembly 26 to move it from its inoperative position into an operative position. In its operative position, the main valve assembly 26 functions to shut off the communication of the open upper end of the cylinder 32 with the atmosphere and to allow full peripheral communication thereof with the reservoir 18.
Communication of the reservoir 18 with the open upper end of the cylinder 32 serves to drive a piston 34 slidably mounted within the cylinder 32 through a fastener drive stroke which is completed when the piston 34 engages a shock absorbing bumper 36 mounted in the main housing section 30 below the lower end of the cylinder 32 which is fixed therein.
The drive stroke of the piston 34 constitutes one stroke of a two stroke cycle of movement that the piston 34 undergoes on a successive basis in accordance with the manual actuating movement of the trigger valve assembly 22. The other stroke of the piston 34, which constitutes a return stroke, is accomplished by a suitable return system 38. The return system can be of any known type. As shown, the return system 38 is of the air plenum chamber type.
The drive stroke of the piston 34 serves to move a fastener driver 40 connected therewith through a drive stroke within a drive track 42 formed within a nose piece assembly 44 fixed below the lower end of the main housing section 30 and forming a part of the portable housing assembly 14. The drive stroke of the fastener driver 40 serves to drive a leading fastener from a supply of fasteners contained within a fastener magazine 46 which has been laterally moved into the drive track 42 along a feed track 48 defined by the magazine 46.
The magazine 46, which is fixed to the nose piece assembly 44 and extends below and is fixed to the handle section 16, can be of any known type. For example, the magazine 46 may be a conventional side loader or a rear loader that is capable of handling fasteners in a stick formation supply, as shown in the Figures, or a coil formation supply of any well known configuration.
The trigger valve assembly 22 is manually actuated by an actuating mechanism which includes a trigger 50 and a contact trip assembly 52. A complete actuation movement serves to move the trigger valve assembly 22 from its inoperative position into its operative position by the coordinated movement of the trigger 50 and contact trip assembly 52. The trigger 50 may be of any conventional construction so as to require any known coordination to effect operation. The contact trip assembly 52 is discussed in greater detail below. In an embodiment, cooperation between the trigger 50 and the contact trip assembly 52 is such that the trigger valve assembly 22 will be moved from its inoperative position into its operative position only when the contact trip assembly 52 is first moved against the work piece and into its operative position and thereafter the trigger 50 is manually moved into its operative position.
In one aspect of the present invention, the device 10 can be adapted to handle any fastener configuration. A pusher assembly 54, which is discussed in greater detail below, is slidably mounted in the feed track 48 of the magazine 46 and is spring-biased to move in a direction toward the drive track 42. As discussed in further detail below, the contact trip assembly 52 and the pusher assembly 54 are part of a dry fire lockout assembly 55, illustrated in
The contact trip assembly 52, in addition to its biasing spring, which is shown at 66 in
As illustrated in
As illustrated in
Returning to
In order for the link 76 and the lower contact arm 72 to be interconnected when the link 76 is in the first orientation, the link 76 and the lower contact arm 72 have cooperating interengaging structures that are configured to provide an interconnection when the link 76 is in the first orientation, and to not provide an interconnection when the link 76 is moved to a second orientation against the bias of the biasing member 82. In an embodiment, as part of the interengaging structure for the lower contact arm 72, the first elongated portion 90 of the lower contact arm 72 includes a recess 94 near an end that is opposite the contact trip foot 74. The recess 94 is generally defined by three surfaces, including a portion of a first surface 96, a second surface 98 that is substantially parallel to the first surface 96, and a third surface 100 that is substantially perpendicular to and connects the first surface 96 and the second surface 98.
The link 76 includes an elongated main body portion 101 that includes a first protrusion 102 that extends substantially perpendicularly from one end of the main body portion 101 and a second protrusion 104 that extends substantially perpendicularly from the other end of the main body portion 101, as illustrated in
The biasing member 82 is configured to bias the link 76 to the first orientation in which the protrusion 102 of the link 76 is received by the recess 94 of the lower contact arm 72, thereby interconnecting the lower contact arm 72 to the link 76, and operatively connecting the lower contact arm 72 to the upper contact arm 70. As illustrated in
Further movement of the lower contact arm 72 causes the link 76 and the upper contact arm 70 to move against the bias of the spring 66 located at the other end of the upper contact arm 70, and allows interaction between the upper contact arm 70 and the trigger 50 for actuation of the trigger valve assembly 22 so that the fastener driver 40 drives a fastener out of the drive track 42 and into the work piece. When the fastener driving device 10 is lifted off of the work piece, the bias of the spring 66 causes the contact trip assembly 52 to move downward relative to the nose piece assembly 44, and back to the position illustrated in
A dry fire lockout portion 114 of the link 76 extends from the end of the link 76 that includes the protrusion 102 at an angle substantially perpendicular to the elongated body portion 101 of the link 76. As illustrated in
During operation of the fastener driving device 10 where there is an adequate supply of fasteners in the magazine 46, the protrusion 102 of the link 76 will remain engaged with the recess 94 of the lower contact arm 72 due to the biasing force provided by the biasing member 82. As the supply of fasteners is depleted, the pusher assembly 54, including the lifter 60, moves towards the drive track 42.
As illustrated in
Movement of the dry fire lockout portion 114 of the link 76 along the second surface 64 to the first surface 63 of the dry fire lockout portion 62 of the lifter 60 causes movement of the link 76 (e.g., rotation or pivoting) about the pin 78 relative to the upper contact arm 70 against the bias of the biasing member 82 to a second orientation. Such movement (e.g., rotation or pivoting) causes the first protrusion 102 of the link 76 to move out of the recess 94 of the lower contact arm 72, as illustrated in
While the dry fire lockout portion 114 of the link 76 and the dry fire lockout portion 62 of the lifter 60 are engaged, as illustrated in
Thus, even though the fastener driving device 10 is in a dry fire lockout condition when the first surface 116 of the dry fire lockout portion 114 of the link 76 of the contact trip assembly 52 and the first surface 63 of the dry fire lockout portion 62 of the lifter 60 of the pusher assembly 54 are engaged, the dry fire lockout condition may be bypassed for the lower contact arm 72 by allowing the lower contact arm 72 to move relative to the link 76 and the upper contact arm 70. This bypass feature may allow potential damage to the lower contact arm 72 in the event the device is accidentally dropped to be reduced, as compared to an arrangement where the lower contact arm is locked in place when the device is in the dry fire lockout condition.
Due to the complementary angled surfaces of the third surfaces 65, 120, as the pusher assembly 54 continues to move towards the nose piece assembly 44, the lifter 60 will cause the link 76 to rotate or pivot about the pin 78, and the first surface 116 of the dry fire lockout portion 114 of the link 76 will reengage the first surface 63 of the dry fire lockout portion 62 of the lifter 60. As illustrated in
Even if the number of fasteners in the supply of fasteners is more than the predetermined level that causes the dry fire lockout assembly 55 to create the dry fire lockout condition, as discussed above, a dry fire lockout condition may still be created by the user of the fastener driving device 10, if desired. For example, if desired, the protrusion 110 of the mounting structure 106 of the link 76 may be pressed by the user against the bias of the biasing member 82 and cause the link 76 to move from the first orientation to the second orientation, thereby moving the first protrusion 102 out of the recess 94 of the lower contact arm 72. This will create the dry fire lockout condition as long as the user presses the protrusion 110 against the bias of the biasing member 82. To return the fastener driving device 10 to its operating condition, with the lower contact arm 72 in its non-actuated position, the user simply releases the protrusion 110 to allow the link 76 to move back to the first orientation and the first protrusion 102 to reengage the recess 94 of the lower contact arm 72.
As illustrated in
A contact trip foot 174, which is mounted to one end of the lower contact arm 172, is configured to engage the work piece. As illustrated in
In order for the link 176 and the lower contact arm 172 to be interconnected when the link 176 is in the first orientation, the link 176 and the lower contact arm 172 have cooperating interengaging structures that are configured to provide an interconnection when the link 176 is in the first orientation, and to not provide an interconnection when the link 176 is moved to a second orientation against the bias of the biasing member 182 via the dry fire lockout device described above. In an embodiment, as part of the interengaging structure for the lower contact arm 172, the first elongated portion 190 of the lower contact arm 172 includes a recess 194 near an end that is opposite the contact trip foot 174. The recess 194 is generally defined by three surfaces, including a first surface 196 that is provided by an end portion 195 of the first elongated portion 190 that is generally perpendicular to the rest of the first elongated portion 190, as illustrated in
The link 176 includes an elongated main body portion 201 that includes a protrusion 202 that extends substantially perpendicularly from one end of the main body portion 201, as illustrated in
The spring 184 is positioned on a spring receiving portion 197 of the second elongated portion 192, as illustrated in
The biasing member 182 is configured to bias the link 176 to the first orientation in which the protrusion 202 of the link 176 is received by the recess 194 of the lower contact arm 172, thereby interconnecting the lower contact arm 172 to the link 176, and operatively connecting the lower contact arm 172 to the upper contact arm 170. When the contact trip foot 174 is pressed against the work piece, the lower contact arm 172 moves upward relative to the nose piece assembly 44 and causes the lower contact arm 172 to initially move slightly relative to the link 176, which causes the second surface 198 to engage the protrusion 202.
Further movement of the lower contact arm 172 causes the link 176 and the upper contact arm 170 to move against the bias of the spring 66 located at the other end of the upper contact arm 170, and allows interaction between the upper contact arm 170 and the trigger 50 for actuation of the trigger valve assembly 22 so that the fastener driver 40 drives a fastener out of the drive track 42 and into the work piece. When the fastener driving device 10 is lifted off of the work piece, the bias of the spring 66 causes the contact trip assembly 152 to move downward relative to the nose piece assembly 44, and back to the position illustrated in
The link 176 also includes a dry fire lockout portion, which may be the same dry fire lockout portion 114 described above with respect to the link 76. Therefore, details of the dry fire lockout portion of the link 176 will not be described herein. In other words, the dry fire lockout device described above may be used with the contact trip assembly 152 illustrated in
When the dry fire lockout device is engaged, i.e. the dry fire lockout portion 114 of the link 76, 176 and the dry fire lockout portion 62 of the lifter 60 are engaged, the link 176 is in the second orientation, as illustrated by
Thus, even though the fastener driving device 10 is in a dry fire lockout condition when the dry fire lockout portion 114 of the link 76, 176 of the contact trip assembly 52, 152 and the dry fire lockout portion 62 of the lifter 60 of the pusher assembly 54 are engaged, the dry fire lockout condition may be bypassed for the lower contact arm 172 by allowing the lower contact arm 172 to move relative to the link 176 and the upper contact arm 170. This bypass feature may allow potential damage to the lower contact arm 172 in the event the device is accidentally dropped to be reduced, as compared to an arrangement where the lower contact arm is locked in place when the device is in the dry fire lockout condition.
While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.
