An Improved Testing Machine.
Year: 1889

page_text: Date of Application, 25th Feb., 1889
Complete Specification Left, 25th Nov., 1889-Accepted, 28th Dec., 1889
PROVISIONAL SPECIFICATION.
An Improved Testing Machine.
I, ROBERT HENRY SMITH, of The Mason Science College, Birmingham, Warwick-
shire, Professor of Engineering, do hereby declare the nature of this invention to be
Is follows:-
The object of my invention is to provide a testing machine for testing materials in
tension, compression, bending, or torsion without the employment of knife edges in
the construction of the machine or weights in the measurement of the forces.
The forces are measured by the bending or other distortion of springs by preference
arranged as follows:-I provide two sets of spring beams (arranged horizontally for
a vertical machine) one set above the other leaving a space between them, each set
consisting of a series of steel bars side by side all by preference of the same
rectangular cross section and of sufficiently small area to enable them to be properly
hardened and tempered with an uniform temper throughout their length. The ends
of the beams forming the upper set are rigidly fixed to the ends of the beams forming
the lower set preferably by means of strong screw cramps with distance blocks between
the upper and lower set; or otherwise they may be connected by a frictionless flexible
joint constructed so that the surfaces may roll on each other but cannot slide or rub
on each other. The beams forming the lower set are fixed centrally to the base of
the machine and the beams in the upper set are connected together centrally by two
cross bars one above and the other below so that when the machine is in use the
forces will be evenly divided between all the beams. Above the said spring beams is
an ordinary hydraulic ram.
When the machine in part above described is employed for testing tensile or
compressive strength the specimen to be tested is connected in the usual way to the
ram and to the central cross bars of the upper set of beams. The distance through
which the two sets of beams are sprung apart will be the measure of the forces
employed. Similarly when measuring a specimen in compression the distance through
which the two sets of beams are sprung together will be the measure of the compressive
force. For bending specimens or subjecting them to transverse strains the cramps
which connect the ends of the beams together are provided with blocks or supports on
which the specimen rests or to which it is fixed and between these supports is a third
block pressed towards the spring beams by the ram so that the force is transmitted
through the end cramps to the lower set of beams. In this case there is no strain on
the upper set of beams but they will move nearer to the lower set of beams and thus
give a measure of the forces employed.
Various devices may be employed for measuring the distances through which the
beams move so as to give an indication of the forces,, such for instance as the
following:-Between the upper and lower set of beams is a cylinder containing a
coloured or other fluid in which works a ram fixed to the upper set of beams; from
this cylinder is a pipe leading to a gauge consisting of a glass tube of small area and
a graduated scale. When the machine is in-use the motion of the ram in the cylinder
causes the fluid to rise or fall in the small glass tube and thus indicate by the scale
the amount of force employed. The said cylinder with its ram and fluid also serves
as a dash pot for absorbing sudden strains on the beams. Or, at the centre of the
lower set of beams there may be a small pulley around which a wire is coiled one end
of the wire being fixed to the upper set of beams; this pulley is fixed to a larger
pulley to which is fixed a wire or string leading to a pencil or pointer. A suitable
spring or weight attached to an extension of the cord keeps the string or wire taut.
The movement of the beams will thus be transmitted through the wire to the small
pulley and multiplied by the large pulley to the pencil or pointer which will give an

page_text: indication of the force employed. Or a system of levers connected to the beams may
be used to operate the pencil or pointer for registering the forces. A beam of light
falling on a small mirror mounted on the above mentioned pulley and reflected and
focussed on a distant scale is also one method whereby I indicate very minute move-
ments of the spring beams.
In using the machine for testing specimens in torsion one end of the test piece is
rigidly fixed in the usual manner in a cramp which is rotated by the power exerted in
the hydraulic cylinder. The other end is clamped in the central hoss of an equal
armed lever whose two ends are pulled by links in opposite directions with equal but
opposite forces. One of these forces is exerted directly by one end of the main spring
beam of the machine. The other force originates at the other end of the same spring
beam but is reversed in direction by help of a small intermediate equal armed lever
before being transmitted to the lever clamped on the end of the test piece.
The machine above described can be arranged either horizontally or vertically.
Dated this 23rd day of February 1889.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.
COMPLETE SPECIFICATION
An Improved Testing Machine.
I, ROBERT HENRY SMITH, of The Mason Science College, Birmingham, Warwick-
shire, Professor of Engineering, 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 :-
The object of my invention is to provide a testing machine for testing materials in
tension, compression, bending, or torsion without the employment of knife edges in
the construction of the machine or weights in the measurement of the forces.
I will describe my invention by referring to the accompanying drawings on which
Fig. 1 illustrates in side elevation, Fig. 2 in end elevation, Fig. 3 in sectional side
elevation, and Fig. 4 in sectional plan, part of a horizontal testing machine constructed
according to this invention for measuring forces up to 100 tons; Figs. 5 and 6
illustrate details of the same; Fig. 7 illustrates partly in section, on an enlarged
scale, the indicator of the said machine, and Figs. 8 and 9 illustrate an appliance for
use with the said machine when testing specimens in torsion.
The same letters of reference indicate the same or corresponding parts in all the
Figures of the drawings.
In carrying out my invention I provide two compound spring beams marked
respectively A and B (arranged vertically in this example but they would be arranged
horizontally for a vertical machine) the beam A being in front of the beam B leaving
a space between them. Each of these spring beams consists of a series of steel bars
marked c laid side by side one above the other in groups of about six each group
being separated by the square portion of the clamping bolts d, h and k hereinafter
referred to. The bars c are all of the same rectangular cross section and of
sufficiently small size to enable them to be properly hardened and tempered with an
uniform temper throughout their length. One of these bars is shewn separately by
Fig. 6. In this particular machine there are thirty-six of these steel bars in each
beam and they are about four feet six inches long and three inches and a quarter deep
by one inch thick in the middle tapering down to one inch square at their ends; but
the number and size of these bars will vary according to the size of the machine.
The bars e forming the back spring beain B are clamped centrally between the strong
standard or back plate D and the vertical cast steel cross bar E by means of the
studs d which pass between the groups of bars c. This standard D is carried by the
bed plate F of the machine and is provided with four strong tie and thrust bolts G to
which the hydraulic cylinder at the other end of the machine is connected. This
hydraulic cylinder is not shewn on the drawings as it forms no part of this invention

page_text: and may be of the usual form. It is provided with a piston and piston rod and the
high pressure water is admitted to either end of the cylinder according as the test to
be made is one in thrust or.in tension. The bars c forming the front spring beam A
are clamped together centrally between the two strong cast steel girder cross-bars
marked respectively H1 H2 by means of studs h passing between the groups of bars c.
The ends of these cross bars H¹ H2 are also secured together by the bolts h² which
also form the piston rods of the pistons in the hydraulic dash pot cylinders I¹ I²
hereinafter described. The cross-bar H₁ is provided with a projecting screw threaded
nose or is otherwise formed for carrying any usual or other form of gripper h* or
other device for holding the test piece whilst under experiment. The extremities of
the spring beams A and B are connected together at each end for tension by thin
steel or other metal bands of which in this case there are six, marked c² each band
being composed of two thicknesses each about five sixty-fourths of an inch thick by
one and a half inches wide; these bands are clamped at either end between the halves
of the cast steel cross-bars K lying outside the extremities of the spring beams and
between these extremities lie other cast steel cross-bars J which abut together and
through which the steel bands e pass. These cross-bars J have their meeting surfaces
shaped cylindrically, the radius of curvature being the thickness of the bar and the
centre of curvature is situated at the end of the unclamped part of the steel tension
bands . The bars K and J are bolted together by the bolts k so as to clamp the
ends of the spring bars between them. In addition to being supported by the back
plate D as above described the spring apparatus above described is suspended by the
six steel bands 12 13 14 15 16 from the upper bridge casting M which is fixed to the
back plate D and supported by the columns m¹ m² the lower ends of which latter are
fixed to the cross girder m³ resting on the bed of the machine and connected to the
back plate D by the ties m*. Of these six steel bands, 12 support the ends of the
spring beam B, 13 14 support the ends of the spring beam A, and the remaining two
support the centre of the front spring beam A, 15 being connected to the centre cross-
bar H2, and to the gripper block. The upper ends of these two steel bands are
connected to adjusting screws passing through the top casting M. and furnished
with nuts above so that the front spring beam A can be adjusted to be exactly
vertical.
When the machine is employed for testing tensile strength, the specimen to be
tested is connected in the usual way to the hydraulic ram at one end of the machine
and to the front spring beam A by the gripper * or otherwise. The distance
through which the two spring beams A and B are sprung apart will be the measure
of the forces employed. Similarly when measuring a specimen in compression or
subjecting it to a bending or transverse strain the distance through which the two
spring beams A and B are sprung together will be the measure of the compressive
bending or transverse strain respectively.
23
Various devices may be employed for measuring the distances through which the
spring beams A and B move so as to give an indication of the forces, such for
instance as the following which is what I prefer :-I provide the two hydraulic dash
pot cylinders II forming part of the back plate D each containing a piston i¹ and
furnished with covers through which work the piston rods 2 above referred to.
Each piston is suitably packed in a manner which reduces the packing friction to a
minimum while it prevents leakage under small pressures, preferably by being
furnished with the oil grooves containing a heavy oil these grooves being smaller
at the periphery of the piston. Similar oil grooves are furnished in the piston rod
glands. In compression tests the liquid from the back end of each of the cylinders I¹ I'
is brought together by the tube N and led into the small glass tube n forming a
which is coiled round the cylinder O in the spiral groove o.
The spaces
gauge
between the coils are marked to form a graduated scale. When the machine is in use
the motion of the pistons ¹ cause the liquid to rise in the small glass tube n and thus
to indicate by the scale the amount of force employed. In tension tests the liquid
from the front end of the dash pot cylinders II' is similarly led into the gauge

page_text: tube n, by the pipe not shewn on the drawings. By making the gauge tube n of a
spiral form I am enabled to use a very long tube in a small compass and obtain a very
open scale so that the divisions representing 10 lbs. of force can be easily seen by
the naked eye at a distance of several feet. The cylinder O is provided with a
pulley p around which passes a continuous cord or band by which the cylinder O can
be rotated so as to bring the level of the liquid always in front of the observer. The
upper end of the small glass tube n is turned upwardly and formed into a bell mouth
for convenience of filling. In order to make the level of the liquid exactly correspond
with the zero point in the scale when there is no force being exerted on the spring
beams, the liquid is filled up to nearly the right level and then, by screwing in the
small screw against a rubber diaphragın piston in the vessel Q which acts upon the
liquid, the exact level is obtained. The connection between the tubes N and the
tube n so as to allow of the cylinder turning round can be effected by the tubes N
connecting to the hollow conical stem`r which fits in the axis of the cylinder to which
the tube n is connected.
9
The cylinders I 12 with their pistons and fluid serve as dash pots for absorbing
sudden strains on the spring beams occurring when a test specimen suddenly gives
way. During the test the pressure in this fluid in both ends of the dash pot
cylinders is extremely small and consequently the packing needed to prevent
leakages offers only a minute frictional resistance to the motion of the spring
beams. After rupture of the specimen and during the recoil of the springs the
pressure in the fluid in that end of the dash pot cylinders which is not being used
to indicate force rises to a high intensity and leakage past the piston and the
gland takes place freely but the record of the forces having been already completed
this leakage is of no consequence. The fluid leaking through the glands is or may
be caught in sheet brass receptacles fixed round the pistons outside the glands.
In using the machine for testing a specimen in torsion one end of the test piece
is rigidly fixed in the usual manner in a cramp, not shewn on the drawings, which
is rotated by the power exerted in the hydraulic cylinder. The other end of the
test piece is clamped in the central boss (see Fig. 8) of an equal armed lever S
whose two outer ends are pulled by links tt2 with equal but opposite forces. One
of these forces is exerted directly by one end u¹ of the equal armed main beam U of
the apparatus connected centrally to the gripper h and the other force originates
at the other end u² of this same beam. The force is reversed in direction by the
help of a small intermediate equal armed lever V before being transmitted to the
lever S clamped to the end of the test piece. The lever V is fulcrumed on a bracket W
fixed to the bed of the machine.
In conclusion I wish it to be understood that I do not limit myself to the precise
details herein before described and illustrated nor to the number of spring beams
employed, as the same may be varied without departing from the nature of my
invention, and that my invention can be applied to a vertical machine similarly as
above described with reference to a horizontal machine.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a machine for testing materials either in tension compression bending or
torsion, the hereinbefore described improved spring beam for measuring the forces,
consisting of a series of small tempered steel bars clamped together side by side,
substantially as hereinbefore described and illustrated, so that a force applied to bend
the said beam will be nearly evenly distributed through the whole of the said bars,
for the purposes set forth.
2. In a machine for testing materials either in tension compression bending or
torsion, the employment of two spring beams A and B of the kind denoted under
Claim 1, the beam B being fixed to a base or back plate which is rigidly connected
to the hydraulic pressure cylinder and the beam A being suspended or otherwise
supported in a plane parallel with the beam B, the outer ends of said beams being

page_text: connected together, so that when a bending force is applied to the beam A such force
will be nearly evenly distributed over the bars of both beams for the purpose and
substantially as hereinbefore described and illustrated.
3. In a horizontal machine for testing materials either in tension, compression,
bending or torsion, the employment of two spring beams A and B of the kind denoted
under Claim 1, the beam B being fixed centrally to a back plate which is rigidly
connected to the hydraulic pressure cylinder, and the outer ends of the beam B being
suspended by hardened steel or other metal bands, the beam A being also suspended
in a plane parallel with the beam B by hardened steel or other metal bands, the
outer ends of the beams A and B being connected together, all substantially in the
manner and for the purposes hereinbefore described and illustrated by the accom-
panying drawings.
4. In a testing machine in which the forces are measured by spring beams of
the kind denoted under Claim 1, the construction and combination of the clamping
bars J and K and the hardened steel or other metal bands c² forming the connection
of the ends of the spring beams and clamping together the small bars of which
the said beams are composed, substantially as hereinbefore described and illustrated
by the accompanying drawings.
5. In a machine of the kind herein referred to for testing materials in tension
compression bending or tension, and in combination with the spring beam B
thereof, the dash pot cylinders I¹ I², or one or more of them, each furnished with
a piston and piston rod or ram connected to the spring bean B, the liquid from
the dash pot cylinder or cylinders being led to a small coiled or other glass tube
forming a gauge, for the purpose and substantially as herein before set forth.
6. A testing machine embodying in combination the improvements hereinbefore
described and illustrated by the accompanying drawings, with or without the torsion
testing apparatus herein before described and illustrated by Figs. 8 and 9.
7. The combination and arrangement of parts constituting the improved apparatus
for transmitting a torsional strain from a testing piece to the force measuring
spring of a testing machine herein before described and illustrated by Figs. 8 and 9
of the accompanying drawings.
Dated this 23rd day of November 1889
ROBERT HENRY SMITH,