New or Improved Method of and Apparatus for Testing the Strength of Wire.
Year: 1892

page_text: Date of Application, 9th Dec., 1892
Complete Specification Left, 11th Sept., 1893-Accepted, 14th Oct., 1893
PROVISIONAL SPECIFICATION.
New or Improved Method of and Apparatus for Testing the Strength
of Wire.
We, BENJAMIN BRADSHAW GLOVER, and WILLIAM JOHN GLOVER, both of
St. Helens Rope Works, St. Helens, in the County of Lancaster, Wire Drawers
and Rope Makers, do hereby declare the nature of this invention to be as
follows:-
-
Hitherto the torsional strength of wire has generally been tested by taking a
short length, say 6 inches, and twisting it until fracture takes place. The lengths
tested of both light and strong wire have generally been about the same and have never
been in lengths proportionate to their size. The consequence is that for 15 BWG
wire about 60 twists may, for example, result in fracture, while, for 11 BWG and
for 17 BWG, fracture may take place at 21 and 41 respectively, and so on. It
will thus be seen that there is no uniformity of results.
Now, by our method, we obtain a greater uniformity of results, and thus we are
able to obtain a better comparison of the relative strengths or quality of the wire
than has bitherto been the case.
In carrying out the invention, we propose to test the wire in a length
proportionate to its diameter. Any suitable proportion may be adopted, but, for
the purposes of example, the following equation is found to be the most con-
venient :-
D × 100=L
where D is the diameter of the wire, and L its length to be tested. This equation,
however, is merely an arbitrary one, as other proportions may be adopted. For
example, if the wires to be tested are of 10, 14 and 19 BWG, their respective
testing lengths would be in the proportions above stated, about 12, 8 and 4 inches
respectively, and fracture would result at approximately the same number of twists
independently of their diameters. We thus obtain a greater similarity of results
than by the old method, and, if fracture takes place at less or more than the
average number of twists, the fact is at once noticed.
The apparatus we propose to employ may consist of a frame having a fixed
poppet head at one end provided with a chuck for holding the wire, and a hand
wheel for rotating the chuck. The frame is provided with a slide, also formed
with a chuck to hold the other end of the wire, and this slide can be moved by
means of a screw so that it can be located at any required distance from the rotating
chuck of the poppet head. As it would be a somewhat tedious operation to
calculate the proportion of the length to the diameter of each size of the wire, we
prefer to provide a scale in which the various proportions are set forth. This scale
may be placed on or in proximity to the slide, which can, therefore, be readily
adjusted in the proper position.
Means are provided for indicating the number of revolutions of the chuck.
Dated this 8th day of Dosambar 1909

page_text: COMPLETE SPECIFICATION.
New or Improved Method of and Apparatus for Testing the Strength
of Wire.
We, BENJAMIN BRADSHAW GLOVER and WILLIAM JOHN GLOVER both of
St. Helens Rope Works, St. Helens in the County of Lancaster, Wire Drawers
and Rope Makers, 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 :-
Hitherto the torsional strength of wire has generally been tested by taking a
short length, say six inches, and twisting it until fracture takes place. The length
tested has generally been about the same for both light and heavy wire, and has
never been in lengths proportionate to their diameter. The consequence is that,
for wire of 15 SWG about 60 twists may, for example, result in fracture, while,
for 11 SWG., the fracture will probably take place at about 21 turns, whereas, on
the other hand, with wire gauge of very thin diameter, a very large number of
twists will be required before the fracture is accomplished; there is thus no
uniformity of results as regards the metal itself, but only as regards each diameter
of each variety of metal.
Now our invention is designed to obtain a much greater uniformity of results, and
thus a better comparison of the relative strengths and quality of the metal of the
wire than has hitherto been the case.
The invention is best described by aid of the accompanying drawings, in
which :-
Figure 1 is a longitudinal elevation:
Figure 2, a vertical section through a y, the wire being omitted:
Figure 3, vertical section through zy, Figure 1: and
Figure 4, a plan view.
In these―
A, is a bed plate; B, fixed poppet head thereon; C and C¹ clutches for holding
the wire; D, shaft in bearings on B carrying the clutch C; E, hand wheel on
shaft D; F, worm on shaft D; G, worm wheel acting as a counter and marked so
as to show the number of revolutions performed by shaft E; H, carriage sliding on
the bed plate A and carrying the chuck C¹, capable of being moved longitudinally
by screw I and crank J. K is a scale fixed on the bed plate giving the position at
which the carriage H ought to stop for each diameter of wire.
The mode of action is as follows:-
The chucks C and C' being placed at the proper distances apart as set forth on
scale K for the particular diameter of wire, which scale is calculated in the manner
hereafter described, the wire is tightened up in the chucks C and C₁ by their
screws, the piece of wire itself having been first inserted absolutely straight. The
handwheel E is now turned until the wire breaks, the number of revolutions is
read off on the wormwheel G. For regulating the scale K, we prefer to test the
wire in a length proportionate to its diameter in whatever proportion may be
adopted, but, for the purpose of example, the following equation is found to be most
convenient
100 D=E.
In this, D is the diameter of the wire, and E the length to be tested. This
equation, however, is merely an arbitrary one, as other proportions may be adopted;
thus, if the wires to be tested are 10, 14 and 19 SWG, their respective distinct
lengths would be in the proportions above stated about 122", 8" and 4" inches
respectively, and the fracture would result in approximately the same number of
twists independently of their diameters for the same strength of metal. We thus
obtain a greater similarity of results than by the old method, and, if fracture takes
place at less or more than the number of twists, the fact is at once noticed.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:-
1. The improved method of testing the strength of wire which consists in taking
the lengths to be tested, placing them between the holding devices exactly
proportionate to their respective diameters, and then twisting the wire while its
holders remain in their respective positions until it breaks, and counting the number
of turns required.
2. The apparatus for testing the strength of wire consisting of a fixed poppet
head carrying a rotatable chuck, a sliding carriage carrying a fixed chuck, and a
counting device fixed thereon.
3. In combination with an apparatus such as described in Claim 1, a regulating
screw for regulating the position of the sliding carriage and a proportionate scale
fixed on or to the carriage or its slide showing the requisite positions for the
carriage proportionate to each diameter of wire to be tested.
4. The manufacture and use of the apparatus for testing the strength of wire,
substantially as herein described and illustrated.
Dated this 9th day of September 1893.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.