Claims
- 1. A screw driving machine for driving a screw having a head into a workpiece, comprising:
- a body;
- a nose section disposed on the body positioned toward the workpiece with respect to the body, the nose section being configured to hold the screw to be driven;
- a hammering mechanism disposed within the body for hammering the screw partially into the workpiece such that the head of the screw is spaced from the workpiece;
- a screwing mechanism for screwing the hammered screw into the workpiece;
- a contact arm slidably disposed with respect to the nose section, the contact arm being at an initial, fully-extended position relative to the nose section when the contact arm is separated from the workpiece and being capable of being pushed in toward the body when the contact arm is pushed against the workpiece; and
- a locking mechanism for preventing the contact arm from sliding relative to the nose section past a predetermined position when the contact arm is pushed against the workpiece such that the nose section is spaced from the workpiece thereby restricting penetration of the screw into the workpiece by the hammering mechanism such that the head of the screw is spaced from the workpiece and for releasing the contact arm after the hammering mechanism hammers the screw into the workpiece to allow the nose section to move toward the workpiece and allow the screw mechanism to screw the screw into the workpiece,
- wherein the locking mechanism comprises means for preventing the locking mechanism from obstructing the return of the contact arm to the initial position after the screwing mechanism screws the screw into the workpiece.
- 2. The screw driving machine according to claim 1, wherein the locking mechanism includes:
- an engaging edge formed on the contact arm; and
- a stopper piece disposed in the nose section, the stopper piece being movable between a first position where the stopper piece engages the engaging edge formed on the contact arm and prevents the contact arm from sliding past the predetermined position and a second position where the stopper piece does not interfere with the sliding of the contact arm.
- 3. The screw driving machine according to claim 2, wherein the screwing mechanism includes an air motor, and the locking mechanism releases the contact arm before the air motor starts rotating.
- 4. The screw driving machine according to claim 3 further comprising an air cylinder device including:
- a cylinder;
- a feed piston slidably disposed within the cylinder; and
- a feed pawl pivotally connected to the feed piston for feeding the screw to be driven, the stopper piece of the locking mechanism being pivotally disposed on the feed pawl.
- 5. The screw driving machine according to claim 2, wherein the screwing mechanism includes a rack and a pinion gear engaging with the rack, the pinion being operatively associated with the stopper piece such that the pinion moves the stopper piece to the second position while the screwing mechanism screws the screw into the workpiece.
- 6. A locking mechanism for a screw driving machine, the screw driving machine having a slidable contact arm for positioning the screw driving machine relative to a workpiece and an air cylinder device for feeding a screw to be driven, the screw driving machine being capable of hammering the screw partially into the workpiece by compressed air, the locking mechanism comprising:
- an engaging edge formed on the contact arm; and
- a stopper piece operatively associated with the air cylinder device, the stopper piece being movable between a first position where the stopper piece engages with the engaging edge formed on the contact arm and prevents the contact arm from sliding past a predetermined position and a second position where the stopper piece does not interfere with the sliding of the contact arm, wherein the air cylinder device normally positions the stopper piece at the first position and moves the stopper piece to the second position at the same time that the compressed air for hammering the screw is discharged.
Priority Claims (2)
Number |
Date |
Country |
Kind |
7-050401 |
Feb 1995 |
JPX |
|
7-325104 |
Nov 1995 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/601,764, filed Feb. 15, 1996, now abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (3)
Number |
Date |
Country |
6-36774 |
May 1994 |
JPX |
443 852 |
Feb 1968 |
CHX |
2 271 523 |
Apr 1994 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
601764 |
Feb 1996 |
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