Abstract

Fastening art with double nuts for a dual-threaded screw structure is provided, in which loosening is not created even if the structure is subjected to vibration. A spring washer is caused to intervene between the nuts, when double nuts of an inner nut and an outer nut are screwed onto a thread portion on which dual-threaded screw is formed. Only by tightening the outer nut, also the inner nut is tightened and the spring washer is compressed. Both axial force for clamping the fastened member and axial force between the nuts can be secured with the spring washer, so that loosening does not occur easily.

IPC Classes  ?

• F16B 33/02 - Shape of threadSpecial thread-forms
• F16B 39/30 - Locking exclusively by special shape of the screw-thread

Abstract

A dual-threaded screw structure having two kinds of threads formed on a shank, namely, a first thread consisting of one or more threads and a second thread having a lead larger than a lead of the first thread is provided herein. The claimed configuration has a beneficial effect of preventing looseness when the screw structure is fastened with double nuts. One embodiment of the present invention exhibits an example of a dual-threaded screw structure, in which a root diameter between the ridges of the hill-like second thread ridges is formed to be larger by 10% of a height of the ridges than an effective diameter of a first thread. In this case, an inner diameter of an internal thread of a second nut for preventing looseness is formed to be larger than the effective diameter of the first thread by 10% of the height of the ridges.

IPC Classes  ?

• F16B 39/30 - Locking exclusively by special shape of the screw-thread
• F16B 35/00 - Screw-boltsStay boltsScrew-threaded studsScrewsSet screws

Abstract

ss1s6s6 are formed larger than the effective diameter d of the first thread (S1) by 10% of the height H of sharp peaks. In this case, the inner diameter of the female thread of a second nut 830, which is a loosening prevention nut, is also formed larger than the effective diameter d of the first thread (S1) by 10% of the height H of the sharp peaks.

IPC Classes  ?

• F16B 39/30 - Locking exclusively by special shape of the screw-thread
• F16B 35/00 - Screw-boltsStay boltsScrew-threaded studsScrewsSet screws

Abstract

The dual-threaded screw structure 1 has a first thread (S1) and a second thread (S2) with various leads formed on the dual-thread portion and has a function of preventing loosening without insufficiency in strength of the dual-thread portion. This dual-thread portion is composed of a first thread (S1) consisting of a coarse thread with a standard pitch P and a specific second thread (S2). The second thread (S2) is formed continuously on the thread ridge of the first thread (S1). The second thread (S2) has a sectional shape of this thread groove same as or substantially same as the first thread (S1), has a same twisting direction as the first thread (S1) and is a multi-threaded thread having threads with a triangular sectional shape and having a lead (L=n*P) a determined number (n)-times of a standard pitch P.

IPC Classes  ?

• F16B 5/02 - Joining sheets or plates to one another or to strips or bars parallel to them by means of fastening members using screw-thread
• B21H 3/06 - Making by means of profiled members other than rolls, e.g. jaws, moved longitudinally or curvilinearly with respect to each other
• F16B 33/02 - Shape of threadSpecial thread-forms
• F16B 25/00 - Screws that form threads in the body into which they are screwed, e.g. wood screws, self-tapping screws

Abstract

This double-screw structure 1 has a loosening prevention function, has a first screw (S1) and a second screw (S2) formed on a double-screw section and having different leads, and the strength of the screw section is adequate. This screw section is configured from a first screw (S1), which comprises a coarse thread screw having a standard pitch P, and a special second screw (S2). The second screw (S2) is formed continuously on the screw thread of the first screw (S1). A cross section of the screw groove has the same or substantially the same shape and the same screwing direction as that of the first screw (S1), and has a lead (L = n*p) that is a prescribed multiple n of the standard pitch P, and the second screw is a screw that has one or more fewer threads than a multi-threaded screw having a triangular cross-sectional shape.

IPC Classes  ?

• F16B 39/30 - Locking exclusively by special shape of the screw-thread
• B21H 3/06 - Making by means of profiled members other than rolls, e.g. jaws, moved longitudinally or curvilinearly with respect to each other
• B21H 3/12 - Making helical bodies or bodies having parts of helical shape articles with helicoidal surface
• F16B 33/02 - Shape of threadSpecial thread-forms
• F16B 35/00 - Screw-boltsStay boltsScrew-threaded studsScrewsSet screws
• F16H 25/20 - Screw mechanisms
• F16H 25/24 - Elements essential to such mechanisms, e.g. screws, nuts