Improvements in Torsion Testing Machines.
Year: 1891

page_text: Date of Application, 14th July, 1891
Complete Specification Left, 13th Apr., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in Torsion Testing Machines.
I RICHARD MOUNTFORD DEELEY, of No. 10 Charnwood Street, Derby,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object the improvement of machines for determining
the torsional strength of metals, alloys, and other constructive materials. .
The bar to be tested is held firmly in the machine centres by square ends or by
cylindrical ends with keyways. The centre through which the stress is to be
measured is supported by thin steel plates slung from the corners of a triangular
frame bolted to the bed-plate of the machine. This centre forms the boss of a
lever the other end of which rests upon a flexible rod carried by a double helical
spring. The hollow pillar in which the spring is secured also carries a gauge to
measure the compression undergone by the spring when a torsional stress is put
upon the test bar. The gauge consists of two pairs of small steel rollers suitably
supported. Clasping these rollers is a frame coupled to the lever below by a
flexible rod. The gauge frame, rising and falling with the end of the lever, rotates
the small rollers, and moves the finger which is attached to the spindle of one of
them. The angle through which the lever moves, even when carrying the full
load, is so small that the flexible bands by which it is centred are not injuriously
strained, and form an almost frictionless support.
The other end of the test bar is carried by a hollow shaft driven from a worm
wheel through a three armed lever and links; the shaft bearings being so arranged
that all the surfaces of the hollow shaft which have to slide longitudinally are also
subject to rotary movement, which gives the test bar freedom to lengthen as it
twists. A graduated circle fixed to the hollow shaft, and a pointer on one of the
bearings, shews the angles of rotation. The worm wheel is driven either by hand,
or by any convenient source of power, through a train of wheels which can be
thrown out of gear by a lever and bolt. One wheel of the train is fitted with a
handle to enable the operator to work the machine by hand, and read off. the
stresses and angles of rotation below the elastic limit, and also to put the centres in
position for inserting the bars to be tested. When the elastic limit has been
exceeded the machine may be driven either by hand or other source of power until
the bar gives way under the stress.
Dated this 11th day of Jul 1801
R. M. DEELEY.
COMPLETE SPECIFICATION.
Improvements in Torsion Testing Machines.
I RICHARD MOUNTFORD DEELEY, of 10 Charnwood Street, Derby, in the
County of Derbyshire, 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 the improvement of machines for determining the
torsional strength of metals, alloys, and other constructive materials.
In the accompanying drawings,
Fig. 1 is a sectional elevation, Fig. 2 a cross section through the line (Fig. 1),
Fig. 3 an end elevation showing a portion of the gauge pillar in section, and
Fig. 4 a plan, of my improved torsion testing machine. Fig. 5 is a section

page_text: Caronga CHC moveable gauge mame, and cig va BCCCION Cough one part
rollers.
The material to be tested is turned and shaped to a form suitable for the machine
centres A A¹. In Fig. 2 the test bar B has a cylindrical central portion b, of small
diameter, and two cylindrical longitudinally grooved, ends C C¹. The ends C C¹
of the test bar B are prevented from turning in the hollow machine centres A A¹
by teeth a a. These teeth run the whole length of the centres A A'so as to secure
test bars of various lengths. The ends of the test bar, and also the holes in the
centres, may be made square.
The centre A' through which the twisting moment is to be measured is slung by.
thin steel plates D from the corners of the frame E, which is firmly bolted to be
bed plate and stand F in such a manner that the centre A¹ may rotate freely
through a very small angle, but be rigidly held in every other direction. The
centre A is adjusted concentrically with the centre A by the screwed ende and
nuts d of the flexible plates.
The suspended centre A₁ forms the boss of a lever G, the pin g in the end of
which rests upon a flexible rod h carried by a spring H secured to the gauge
pillar I. The spring H is fixed in the pillar I by set screws i in such a manner
that the spring can easily be removed and replaced by one of lighter or heavier
section. The pillar I, which is firmly secured to the stand F, also carries a
gauge J to measure the extension of the spring H and therefore the twisting
moment on the lever G resulting from the strain put upon the test bar B. The.
gauge motion consists of two pairs of small rollers; supported in a frame K
secured to the case of the gauge J. Clasping these small rollers, and capable of
rolling on them, is a moveable frame. This frame consists of two portions !!
firmly pressed upon the rollersjj by a spring. One portion of the frame is
coupled by a flexible rod M to the pin y in the jaw of the lever G and moves with
it. Fig. 6 is a section through the line az, Fig. 5, and shows the central ribs,
which act as guides, on the rolling faces of the two portions of the frame, and
run in grooves on the rollers j. . The spindle m, forming the bearing of one of these
rollers, is elongated and to it is attached the gauge finger L. Every movement of
the lever G is consequently indicated by the gauge finger L. The angle through
which the lever G moves, even when the maximum stress is on the test bar, is BO
small that the flexible bands D, by which the centre A' is held in position, are not
injuriously strained and form almost frictionless elastic supports. In case the jaw
of the lever G should be displaced laterally by a heavy-load, two small balls e e
are fitted in vertical grooves in the ends of the pin g. These balls roll against
faces screwed into the gauge pillar I. The gauge J is graduated by means of
weights slung from the lever G.
The other end of the test bar B is carried by the hollow centre A. This centre
is a hollow shaft shaped internally in a manner similar to A'. It is driven by a
worm wheel N through the links O and the three armed lever P, which is keyed to
the centre A. The worm wheel revolves on a bush p secured to the bracket Q and
liner R. As there is a considerable amount of clearance between the lever P and
the boss of the worm wheel N the hollow shaft forming the centre A can slide
longitudinally in the liner R and the bracket Q the bearings being so arranged
that all the friction surfaces of the centre A which have to slide longitudinally are
also subject to rotary movement, and the test har has almost perfect freedom to
lengthen as it twists. A graduated circle S fixed to the centre A and a finger on
the bracket Q' show the angle of rotation. The machine may be driven by hand;
or any other convenient source of power, through a shaft and worm T, a train of
wheels U, a shaft W, and pulley W. A fast and loose pulley driven by a belt
may be used in place of the fixed pulley W. By means of the bolt and lever V,
which carries one of the wheels of the train U, the train can be thrown out of gear.
One wheel is fitted with a handle Y to enable the operator to work the machine
and read off the stresses and angles of rotation below the yield point and elastic
limit, and also to place the centres A A' in position for inserting the bars to be

page_text: tested. When the yield point has been exceeded, and the speed of rotation of the
centre A can be increased, the machine may be driven from the pulley W¹ and the
shaft W until the test bar breaks under the load.
Having now particularly described and ascertained the nature of my inven
tion and in what manner the same is to be performed I declare that what I
claim is
.1. The combination of the longitudinally sliding and rotating centre A, by means
of which the stress is applied to the test bar, and the centre A' supported by flexible
plates substantially as described.
2. The combination of the spring H supporting the lever G and the moveable
gauge frame sliding on the fixed rollers j; one of which carries the gauge finger L,
substantially as described.
-
3. The combination of the lever and the locking bolt V, for throwing the machine
out of gear, and the worm and worm wheel N substantially as described.
4. The torsion testing machine substantially as described and shown in the
drawings.