Year: 1886

page_text: I, JOSEPH HARTLEY WICKSTEED of Wellhouse Foundry, Leeds; in the County
of York, Engineer do hereby declare the nature of this invention to be
follows:-
This invention relates to the steel yards of Testing machines and enables the
same steel yard and poise weight to be used with advantage for either strong or for
delicate test pieces.
The invention consists in the arrangement of a series of knife edges in order that
the fulcrum or centre upon which the steel yard oscillates may be at varying distances
from the back centre or knife edge from which the stress is taken to the test piece.
Thus the same steel yard might be at pleasure used either as a scale beam with arms
of equal length or as a lever with arms in the proportion of a hundred to one or
of any other proportion or "mechanical advantage "that might be most suitable
for the strength of the test piece. I carry out this invention by having a series of knife
edges fixed along the centre line of the steel yard and by arranging the supporting
plates upon which these knife edges act in such a way that any one of them can be
brought to bear under the particular knife edge which at the time it is wished to use
as the fulcrum of the lever whilst the remaining supporting plates are so far withdrawn
as not to come in contact with their corresponding knife edges whilst the steel yard
oscillates through its necessary range.
Dated this 21st day of February 1886.
W. P. THOMPSON & BOULT,
Agents.

page_text: Improvements in Testing Machines.
I, JOSEPH HARTLEY WICKSTEED of Wellhouse Foundry, Leeds, in the County of
York, Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described in and by the following
statement:
Fig. 1 shows the outline of a testing machine made with my improvements
and fig. 2 shows the series of knife edges in section to a larger scale.
The steelyard A figure 1 has a series of three knife edges B, C and D upon any of
which it can be made to oscillate. The knife edge B is at a distance of 4 inches from
the back centre or knife edge from which the stress is taken to the test piece and
when Bis used as a working fulcrum the two ton poise weight W will measure
stresses up to 120 tons by reading from the top scale on the steol yard which shows
2 inches travel of the poise weight per ton measured. The knife edge C is 8 inches
from the back centre and when it is used as the working fulcrum the poise will
measure stresses up to 80 tons by reading from the middle scale which shows 4 inches
travel of the poise per ton measured.
The knife edge D is 16 inches from the hack centre and when it is used as the
working fulcrum the poise weight will measure stresses up to thirty tons by reading
from the bottom scale which shows 8 inches travel of poise per ton measured. In
order to bring to bear upon its supporting plate the particular knife edge which at
the time it is wished to use as the working fulcrum I make the plates upon
which C and D are supported when at work in such a way that they may be readily
withdrawn so as not to come in contact with those knife edges while the steel yard
oscillates upon the fulcrum B. For doing this I show an arrangement at E and F
figure 2. These are circular gudgeons which carry the supporting plates
which are let into a groove in each gudgeon and project, beyond the circumference
of the gudgeon.
When the gudgeon is revolved so as to bring the projecting plate uppermost then the
corresponding knife edge bears upon it but when the gudgeon is revolved so that the
projecting plate descends below the level of the circumference of its gudgeon then
the corresponding knife edge does not come into contact with its supporting plate and
the lever oscillates upon the fulcrum B. And in order, that when the knife edges C
or D are used the knife edge B may not come into contact with its supporting plates
it is provided that the supporting plates for C and D are higher than the one for B;
so that when the steelyard is mounted upon C or D for its fulcrum it is sufficiently
high to oscillate throughout its working range without bringing its knife edge B in
contact with its supporting plate. In order conveniently to mount the steelyard upon
any of its fulcra I provide a-removable rest at G figure-1-and a lifting screw at H and
by these means I am able to lift the lever clear of all its fulcra and can afterwards
let it down upon whichever supporting plate has been brought into the highest position.
I am able by this improvement to increase the delicacy of the machine for light

page_text: testing and to increase its power for heavy testing without making any addition to or
subtraction from the standard poise weight of 2 tons. With the uppermost scale that
measures up to 120 tons I can read variations of stress down to 20 lbs. with the lower-
most scale I can read variations down to 2 lbs and besides the advantage which I get
from reading a larger scale I am able by having alternative fulcra to reserve finer
knife edges to use for the more delicate testing.
The mechanism I show for revolving the gudgeons E and F figure 2 is a small
worm and worm segment fitted for each gudgeon and by these the gudgeons are
held securely whether in or out of use. The poise, weight W figure 1 in my
improved machine is traversed back for zero to the negative end of the steelyard
until it balances the longer or positive end and as the balancing. point varies
according to which of the fulcra the steel yard oscillates upon so the poise travels
upon the steelyard from a different starting point in each case
as shown
on the drawing by the different longitudinal positions of the top, middle and
lower scales.
Having now particularly described and ascertained the nature of my said invention.
and in what manner the same is to be performed, I wish it to be understood that I do
not confine myself to the particular method which I show for bringing the alternative
centres into use, but I declare that what I claim is
--
The use of alternative centres in testing machines to enable the same steelyard and
poise weight to be used with advantage for either strong or for delicate test
pieces.
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