NOTICE OF COPYRIGHT

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.

BACKGROUND OF THE PRESENT INVENTION

Field of Invention

The present invention relates to a screw depth adjuster, especially to a screw depth adjuster in which screws are positioned after being driven to the required depth from surfaces of workpiece/material for preventing damages on the surface of the workpiece/material and damages on the screw caused by being driven too much.

Description of Related Arts

Screw depth adjusters are well known to people skilled in the art, as revealed in US Pat. Pub. No. 20080289459, U.S. Pat. Nos. 5,235,327, 4,736,658, etc. Refer to US Pat. Pub. No. 20080289459, a screw/depth control driver device used for preventing the screw from driving beyond the depth required by users is revealed. The device has a free-spinning sleeve17. In order to achieve the above purpose, a device is provided to set and hold the amount of return by the sleeve before the torque driving the screw is released preventing the screw from being over-driven. The device further includes a screw driving device12, a depth control stop/setting nut14and a lock-retaining ring16. The screw driving device12has a thread pattern to allow the depth control stop14to be moved forward or backward and held along the screw driving device12to control the depth of the screw being driven. The sleeve17can rotate freely on the screw driving device12. The lock retaining ring16is unable to rotate when engaged over the depth control stop14. While in use, the depth control stop is rotated on the screw driving device to be fixed at a selected longitudinal position of the device. Then the lock retaining ring16is slid back over the depth control stop14. When the screw driving device is driven forward, the depth control stop comes to butt against the screw control sleeve so that the screw driving device cannot be driven forward any further and hence the screw cannot be driven forward any further. To use the device, the depth control stop14, the lock retaining ring16and the sleeve17are moved in turn.

In order to set a desired depth of the screw, the depth control stop14is first rotated clockwise/anti-clockwise. Then the lock retaining ring16is slid back over the depth control stop14. The sleeve17is then slid completely forward until a flared end is beyond. However, the position of the sleeve17during the driving is unable to learn in a real-time manner. Thus the depth control stop14has to be moved multiple times for adjustment. During each time of adjustment of the driving depth, the sleeve17needs to be moved first and then the lock retaining ring16is slid forward to disengage the depth control stop14, hence the depth control stop14can rotate and move for adjustment. Users can't learn whether the position of the sleeve17is correct for the desired depth of the screw while adjusting the depth control stop. Therefore the device is inconvenient to use.

Moreover, the screw/depth control driver device further includes two longitudinally-oriented grooves30and the lock retaining ring16has two protrusions27on opposite sides that fit into the longitudinally-oriented grooves30correspondingly. The above design has significant shortcomings. The power tools available on the market now provide greater rotary torsion. The most common range of rotary torsion is 150-240 Newton-meter (Nm) and the revolutions per minute (RPM) is ranging from 3200 to 3600. When the sleeve17is in contact with the workpiece, the IPM (impacts per minute) is 3500˜4000. The impact force acted on the sleeve17is returned to the depth control stop14so that the protrusions27and the longitudinally-oriented grooves30hit each other and cause deformation. The protrusions27of the depth control stop14are unable to move smoothly in the longitudinally-oriented grooves30once being deformed, and even easily locked in the grooves30. Thereby the depth control stop14can't be moved for adjustment.

Furthermore, the depth control stop14contains detent balls28each of which fit over a spring15. Thus the dent balls28can be elastically protruding from or popped in the depth control stop14. The lock retaining ring16has a groove on the inside designed25to allow the dent balls28set into the depth control drop14to be engaged into the lock retaining ring16to hold the lock retaining ring16into place over the depth control stop14. During adjustment, the depth control drop14needs to be rotated a circle until the dent balls28being mounted into the grove25correspondingly. There is a limit on the rotation of the depth control drop14—at least half a circle as one scale. Thereby the screw/depth control driver device10doesn't have fine-adjustment function.

Thus there is room for improvement and there is need to provide a novel screw depth adjuster that solves the problems mentioned above.

SUMMARY OF THE PRESENT INVENTION

Therefore it is a primary object of the present invention to provide a screw depth adjuster which not only allows users to learn the depth of the control member/sleeve going to be adjusted in a real-time manner but also avoids damages caused by vibrations generated during the adjustment.

It is another object of the present invention to provide a screw depth adjuster which provides fine adjustment of the depth of screws so that the screw can be driven to the position required properly.

In order to achieve the above objects, a screw depth adjuster used for allowing users to control the depth of the screw being driven into the workpiece according to the present invention includes a rod assembled with a control member, a driving member and a flared sleeve. The rod consists of a first portion and a second portion formed by extension of the first portion. The first portion is a polygonal rod used for connection with power tools while the second portion is a threaded rod with an assembly portion extended from the rear end. A first plane and a second plane are disposed on two sides of the threaded rod longitudinally and arranged in parallel to each other. The control member consists of a push portion and a polygonal stopper extended from the push portion. Thereby the control member can be pushed and moved slidably axially on the threaded rod. The driving member is provided with an adjustment portion and a sleeve portion extended from the adjustment portion. A polygonal second passage is disposed on the adjustment portion and a threaded third passage is formed by extension of the second passage to the sleeve portion. The shape of the polygonal second passage matches the shape of the polygonal stopper of the control member. The flared sleeve can be pushed by the driving member to be moved on the rod while the control member is used to lock the driving member so that the driving member can't be rotated and moved on the rod any further. The control member is for positioning the driving member. The driving member used for pushing the flared sleeve can be moved forward/backward on the rod and positioned at the rod for adjustment of the depth of the screw. The flared sleeve is idling once abutting against the surface of the workpiece/material so that the screw will not be driven beyond the depth required in the workpiece.

