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(11) | EP 1 319 474 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Screw driving gun having a slider member provided with a screw guiding spring |
| (57) A screw driving gun includes a barrel 33 extending from a gun housing 31 and defining
a shaft-receiving chamber 330C to receive a driving shaft 313 for driving a screw
361, and a slider member 34 coupled slidably to the barrel 33. A front portion 343
of the slider member 34 defines a screw-guiding chamber 343C and is formed with a
mounting plate 38 in the screw-guiding chamber 343C. A screw guiding curved spring
37 has a front part 371 fixed on the mounting plate 38 adjacent to an abutting end
3431 of the slider member 34, a rear part 372, a middle biasing part 373 which is
disposed between the front and rear parts 371,372 and which has an apex 373A generally
aligned with the axis of the screw driving shaft 313, and a curved guiding face 373C
that extends from the rear part 372 to the apex 373A. The guiding face 373C can engage
the screw 361 when the screw 361 is pushed into the screw-guiding chamber 343C by
the screw driving shaft 313 to prevent the screw 361 from inclining relative to the
axis of the driving shaft 313. |
[0001] The invention relates to a screw driving gun, more particularly to a screw driving gun having a slider member provided with a screw guide spring.
[0002] A conventional screw driving gun is adapted for use with a screw feed belt that has a belt body and a plurality of screws detachably retained on the belt body, and includes a gun housing, a tubular barrel, a tubular slider, a screw driving shaft, and a positioning member.
[0003] The tubular barrel has a first peripheral wall with a rear end mounted on the gun housing, and a front end. The first peripheral wall defines a chamber in a longitudinal direction. The tubular slider has a second peripheral wall with a rear portion that is coupled slidably to the front end of the barrel so as to be slidable relative thereto in the longitudinal direction, and a front portion that extends forwardly from the barrel. The front portion of the slider is formed with a slot that extends in a transverse direction relative to the longitudinal direction and that is adapted for passage of the belt body therethrough in order to register a selected one of the screws with the chamber of the barrel. The screw driving shaft has a driven end and a turning bit. The screw driving shaft is accommodated in the chamber of the barrel such that the turning bit is extendible into the tubular slider. The screw driving shaft is rotatable axially such that the turning bit is adapted to drive rotatably the selected one of the screws. A drive unit is mounted in the gun housing, and is coupled to the driven end of the screw driving shaft so as to drive rotatably the screw driving shaft. The positioning member is secured to the front portion of the tubular slider for abutting against the surface of a work piece that rests on a wall structure so that the work piece can be fastened on the wall structure when the selected one of the screws is driven and rotated by the turning bit upon operation of the drive unit.
[0004] A disadvantage of the conventional screw driving gun resides in that, in case the selected screw has a relatively long length in the longitudinal direction, the belt body is unable to maintain the orientation of the screw in the longitudinal direction. Thus, inclination of the screw relative to the longitudinal direction by virtue of gravity will occur during the driving operation of the screw.
[0005] Therefore, the object of this invention is to provide a screw driving gun having a slider member which is provided with screw guiding spring to overcome the aforesaid disadvantage that is generally associated with the conventional screw driving gun.
[0006] The screw driving gun of the present invention includes a barrel extending from a gun housing and defining a shaft-receiving chamber to receive a driving shaft for driving a screw, and a slider member coupled slidably to the barrel. A front portion of the slider member defines a screw-guiding chamber and is formed with a mounting plate in the screw-guiding chamber. A screw guiding curved spring has a front part fixed on the mounting plate adjacent to an abutting end of the slider member, a rear part, a middle biasing part which is disposed between the front and rear parts and which has an apex generally aligned with the axis of the screw driving shaft, and a curved guiding face that extends from the rear part to the apex. The guiding face can engage the screw when the screw is pushed into the screw-guiding chamber by the screw driving shaft to prevent the screw from inclining relative to the axis of the driving shaft.
[0007] Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiment of this invention, with reference to the accompanying drawings, in which:
Figure 1 is a schematic fragmentary view of a preferred embodiment of a screw driving gun according to this invention;
Figure 2 is an enlarged exploded perspective view of a slider member employed in the preferred embodiment shown in Figure 1; and
Figure 3 is a schematic fragmentary view illustrating how a screw guiding curved spring prevents inclination of a screw being driven by the preferred embodiment.
[0008] Referring to Figures 1, 2 and 3, the preferred embodiment of a screw driving gun 30 of the present invention is adapted for use with a screw feed belt 36 that includes a belt body 360 and a plurality of screws 361 detachably retained on the belt body 360. The preferred embodiment includes a gun housing 31, a tubular barrel 33, a hollow slider member 34, a screw driving shaft 313, a drive unit 349, and a screw guiding curved spring 37.
[0009] The tubular barrel 33 has a peripheral wall 330 with a rear end 331 mounted on the gun housing 31, and an opposite front end 332. The peripheral wall 330 defines a shaft-receiving chamber 330C in a longitudinal direction.
[0010] The screw driving shaft 313 is disposed in the shaft-receiving chamber 330C of the barrel 33, and has a driven end 313D and a turning bit 313B opposite to the driven end 313D.
[0011] The drive unit 349 is mounted in the gun housing 31, and is coupled to the driven end 313D of the screw driving shaft 313 so as to drive rotatably the screw driving shaft 313.
[0012] The slider member 34 includes a slidable housing 340 that has a bottom opening 345, a rear portion 341 which is coupled slidably to the front end 332 of the barrel 33 so as to permit the slidable housing 340 to be slidable relative to the barrel 33 in the longitudinal direction, a front portion 343 which defines a screw-guiding chamber 343C, and an intermediate portion 342 which extends between the front and rear portions 343,341 and which defines a screw-receiving chamber 342C. The rear and intermediate portions 341,342 of the slidable housing 340 cooperatively define a belt passage 340B therebetween that extends in a transverse direction relative to the longitudinal direction and that is in spatial communication with the bottom opening 345. The screw-receiving chamber 342C of the slidable housing 340 is adapted to receive a selected one of the screws 361 from the screw feed belt 360 when the latter is fed thereinto via the bottom opening 345. The screw feed belt 36 is fed into the screw-receiving chamber 342C by intermittent rotation of a turning wheel 35 that is disposed rotatably in the rear portion 341 of the slidable housing 340. Since the feature of the subject invention does not reside in the structure and connection relationship between the wheel 35 and the drive unit, a detailed description of the same is omitted herein for the sake of brevity.
[0013] The front portion 343 of the slidable housing 340 has an abutting end 3431 which is adapted to abut against a work piece surface 38 and which is formed with a screw-extension hole 3432 in alignment with the shaft-receiving chamber 330C. The slider member 34 further has a mounting plate 38 which projects from an inner face of the slidable housing 340 into the screw-guiding chamber 343C and which extends between the front portion 343 and the intermediate portion 342 in a direction parallel to an axis defined by the screw driving shaft 313. The turning bit 313B of the screw driving shaft 313 is extendible into the screw-receiving chamber 342C, and is rotatable axially such that the turning bit 313B is adapted to drive rotatably the selected one of the screws 361 in the screw-receiving chamber 342C.
[0014] The curved spring 37 is disposed in the screw-guiding chamber 343C, and has a front part 371 disposed securely on the mounting plate 38 adjacent to the abutting end 3431 of the front portion 343, a rear part 372 slidably disposed on the mounting plate 38 adjacent to the screw-receiving chamber 342C, a middle biasing part 373 which is disposed between the front and rear parts 371,372 and which has an apex 373A generally aligned with the axis of the screw driving shaft 313, and a curved guiding face 373S that extends from the rear part 372 to the apex 373A and that is adapted to engage the selected screw 361 when the latter is pushed into the screw-guiding chamber 343C from the screw-receiving chamber 342C by the screw driving shaft 313. Under this condition, the curved spring 37 provides an upwardly biasing force to prevent the selected screw 361 from inclining relative to the axis of the screw driving shaft 313 by virtue of gravity while the selected screw 361 is being driven rotatably into the work piece surface 380 via the screw-extension hole 3432 in the abutting end 3431 by the turning bit 313B of the screw driving shaft 313. Note that the curved spring 37 can be easily manufactured at a low cost, and mounting of the same in the slidable housing 340 can be easily done.
[0015] Preferably, the slidable housing 340 is formed from left and right housing halves which are detachably coupled to each other to define the bottom opening 345 via which the selected screw 361 extends prior to being received in the screw-receiving chamber 342C. The mounting plate 38 is formed on the right housing half. A spring-mounting post 30P is disposed on the right housing half in such a manner that the post 30P extends integrally from a free end of the mounting plate 38 in the transverse direction relative to the axis of the screw driving shaft 313. The front part 371 of the curved spring 37 defines a tubular sleeve that is sleeved around the spring-mounting post 30P.
a gun housing 31;
a tubular barrel 33 having a peripheral wall 330 with a rear end 331 mounted on the gun housing 31, and an opposite front end 332, the peripheral wall 330 defining a shaft-receiving chamber 330C in a longitudinal direction;
a screw driving shaft 313 disposed in the shaft-receiving chamber 330C of the barrel 33, and having a driven end 313D and a turning bit 313B opposite to the driven end 313D;
a drive unit 349 mounted in the gun housing 31 and coupled to the driven end 313D of the screw driving shaft 313 so as to drive rotatably the screw driving shaft 313;
a hollow slider member 34 including a slidable housing 340 that has a bottom opening 345, a rear portion 341 which is coupled slidably to the front end 332 of the barrel 33 so as to permit the slider member 34 to be slidable relative to the barrel 33 in the longitudinal direction, a front portion 343 which defines a screw-guiding chamber 343C, and an intermediate portion 342 which extends between the front and rear portions 343,342 and which defines a screw-receiving chamber 342C, the rear and intermediate portions 341,342 cooperatively defining a belt passage 340B therebetween that extends in a transverse direction relative to the longitudinal direction and that is in spatial communication with the bottom opening 345, the screw-receiving chamber 342C of the slider member 34 being capable of receiving a selected one of the screws 361 from the screw feed belt 360 when the screw feed belt 360 is fed thereinto via the bottom opening 345 in the slider member 34, the front portion 343 further having an abutting end 3431 which is adapted to abut against a work piece surface 38 and which is provided with a screw-extension hole 3432 in alignment with the shaft-receiving chamber 330C, the slider member 34 further having a mounting plate 38 which projects from the slidable housing 340 into the screw-guiding chamber 343C and which extends between the front portion 343 and the intermediate portion 342 in a direction parallel to an axis defined by the screw driving shaft 313, the turning bit 313B of the screw driving shaft 313 being extendible into the screw-receiving chamber 342C and being rotatable axially such that the turning bit 313B is adapted to drive rotatably the selected one of the screws 361 in the screw-receiving chamber 342C; and
a screw guiding curved spring 37 disposed in the screw-guiding chamber 343C, having a front part 371 disposed securely on the mounting plate 38 adjacent to the abutting end 3431 of the front portion 343, a rear part 372 disposed slidably on the mounting plate 38 adjacent to the screw-receiving chamber 342C, a middle biasing part 373 which is disposed between the front and rear parts 371,372 and which has an apex 373A generally aligned with the axis of the screw driving shaft 313, and a curved guiding face 373S that extends from the rear part 372 to the apex 373A and that is adapted to engage the selected one of the screws 361 when the selected one of the screws 361 is pushed into the screw-guiding chamber 343C from the screw-receiving chamber 342C by the screw driving shaft 313, the curved spring 37 providing an upwardly biasing force to prevent the selected one of the screws 361 from inclining relative to the axis by virtue of gravity while the selected one of the screws 361 is being driven rotatably into the work piece surface 380 via the screw-extension hole 3432 in the abutting end 3431 by the turning bit 313B of the screw driving shaft 313.