STEELBALL IMPLEMENTATION IN BLIND THREADHOLES TO PROTECT AGAINST THREAD FRETTING
Publication Date: 2013-Jul-10
The IP.com Prior Art Database
The present invention proposes a steel ball in a tapped blind hole to determine exact position of a stud bolt. The steel ball in the tapped blind hole protects the screw and bolts from thread fretting. The steel ball in the blind thread hole prevents over tightening of the stud bolts.
The present invention relates generally to a blind thread hole and more particularly to a steel ball implementation into the blind thread hole to protect against thread fretting.
In general, removal of a stud bolts results in destruction of the tapped blind thread hole. The tapped blind thread hole is damaged while tightening connection between the stud bolt and a nut. The nut is screwed onto the stud bolt and tightened in accordance with torque or rotation angle procedure. The stud bolts may turn further into the thread run out. Removal of the stud bolts delays workflow as repair work consumes time. Repair of the damaged blind thread hole is performed by a helicoil or a special thread bushing with inner and outer thread. Subsequently, a new thread is created in bedplate. Accordingly, heavy tools and repair parts are required to perform such repair task.
A conventional technique includes stud bolts with a cylindrical end without thread. The cylindrical end prevents over-tightening of the stud bolts. However, such conventional technique is expensive as the stud bolts are not standardized.
It would be desirable to have an improved technique for determining exact position and prevent over-tightening of the stud bolts in the blind thread hole.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 depicts steel ball with corresponding screw in the blind thread hole.
Figure 2 depicts a comparative measurement to check presence of steel ball.
The present invention proposes a steel ball in a tapped blind hole to determine exact position of a stud bolt. The steel ball in the tapped blind hole protects the screw and bolts from thread fretting. Thread fretting refers to wear and corrosive damage at rough contact surface. The steel ball in the blind thread hole prevents over tightening of the stud bolts.
The steel ball size depends on the thread hole size. The steel ball may be introduced into the blind thread hole after appropriate size determination. Run-out geome...