Improvements in Screw Threads, and in the Production of the same.
Year: 1893

page_text: Date of Application, 29th Mar., 1893
Complete Specification Left, 28th Dec., 1893-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Screw Threads, and in the Production of
the same.
1, EDWARD TILEY LAMBERT, of Alpha Tube Works, Ablewell Street,
Walsall, Staffordshire, Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention has for its object to lock a bolt or screw in a nut or in a threaded
hole, or a pipe in a socket or the like in such manner as to prevent unscrewing.
when the parts are exposed to vibration or shocks.
For this purpose I form the thread upon the bolt; that is to say the external
screw thread; with a longitudinal rib or ridge which on one side partially fills the
hollows of the thread. In screwing the parts together as the bolt or screw enters
the threaded hole this rib or ridge is crushed and becomes tightly jammed and the
metal of the one part so engages with that of the other part that vibration will not
cause unscrewing.
It is preferred that the rib or ridge should be upon the bolt or external screw
but it may be within the nut or threaded hole.
I make screws suitable for the purpose by means of a milling tool provided with
a series of annular ridges and furrows corresponding to the screw threads. Whilst
this tool is revolving I present the bolt or screw blank to it and give to the bolt
or blank a slow rotation and end wise traverse. Something less than a complete
rotation is made and consequently the thread is not completely cut but the required
ridge or rib is left.
In a similar manner I can cut internal screw threads and leave a locking ridge;
but it is preferred that this ridge should be upon the bolt or external screw
thread.
Dated this 28th day of March 1802
E. T. LAMBERT.
COMPLETE SPECIFICATION.
Improvements in Screw Threads, and in the Production of
the same.
I, EDWARD TILEY LAMBERT, of Alpha Tube Works, Ablewell Street,
Walsall, Staffordshire, Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
This invention has for its object to lock a bolt or screw in a nut or in a threaded
hole, or a pipe in a socket or the like in such manner as to prevent unscrewing
when the parts are exposed to vibration or shocks.
For this purpose I form the thread upon the holt; that is to say the external
screw thread; with a longitudinal rib or ridge which on one side partially fills the
hollows of the thread. In screwing the parts together as the bolt or screw enters
the threaded hole this rib or ridge is crushed and becomes tightly jammed and the
metal of the one part so engages with that of the other part that vibration will not
cause unscrewing.
It is preferred that the rib or ridge should be upon the bolt or external screw
but it may be within the nut or threaded hole.

page_text: I make screws suitable for the purpose by means of a milling tool provided with
a series of annular ridges and furrows corresponding to the screw threads. Whilst
this tool is revolving I present the bolt or screw blank to it and give to the bolt
or blank a slow rotation and end wise traverse. Something less than a complete
rotation is made and consequently the thread is not completely cut but the required
ridge or rib is left.
In a similar manner I can cut internal screw threads and leave a locking ridge;
but it is preferred that this ridge should be upon the bolt or external screw
thread.
In order that my said invention may be fully understood I will proceed to
describe the drawings annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of a screw bolt with a locking thread upon it in
accordance with my invention. In this figure the nut is also shown.
Figure 2 is a transverse section taken through the bolt in that portion of the
threaded part where it is desired that the locking of the nut upon the bolt should
take place.
Figure 3 is an end view of the bolt and nut.
Figures 4, 5 and 6 are similar to the Figures 1, 2 and 3 and show a modification.
It will be seen' that at the part marked a the screw thread is not completely
formed; the grooves do not continue completely around the stem of the bolt but a
narrow ridge of more or less prominence is left where the screw thread is not cut to
its full length. As shown in these figures the ridge occupies the whole depth of
the thread, but this is not an essential feature as in some cases a lesser depth may
be preferred..
Figures 4, 5 and 6 show that there may be two ridges a a left upon the stem of
the bolt where the screw thread is not cut or is not cut to the full depth. In
cutting these screw threads a cylindrical milling tool is employed; it has cutting
teeth around it corresponding to the thread to be produced on the bolt or other
part, and it is rapidly rotated. The bolt or part on which the thread is to be
produced is held with its axis parallel to that of the milling tool and whilst it is
slowly rotated it is brought into contact with the tool, but in the parts where it is
desired to leave a ridge the rotation of the bolt or part is not allowed to be
completed. Or if two or more ridges be required the bolt or part whilst it still
revolves is partially withdrawn from the milling tool for a short period and is then
replaced.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is
1. A bolt or rod or tube or other part having a screw thread substantially as
described partially cut so as to leave a locking ridge as herein set forth.
2. The means herein described for producing a locking thread on a bolt or
rod or tube or other part, by means of a milling tool working partly around the
bolt or other part leaving a ridge.
Dated this 15th day of December 1893.
E. T. LAMBERT.