IMPROVEMENTS IN APPARATUS FOR TESTING THE STRENGTH OF MATERIALS APPLICABLE ESPECIALLY FOR TESTING CEMENT 23
Year: 1882

page_text: LETTERS PATENT to William Porter of Manor Park Lee in the County of
Kent Engineer for an invention of " IMPROVEMENTS IN APPARATUS FOR
TESTING THE STRENGTH OF MATERIALS APPLICABLE ESPECIALLY FOR TESTING
CEMENT
23
PROVISIONAL SPECIFICATION left by the said William Porter at the Office
of the Commissioners of Patents on the 2nd May 1882.
WILLIAM PORTER of Manor Park Lee in the County of Kent Engineer
"IMPROVEMENTS IN APPARATUS FOR TESTING THE STRENGTH OF MATERIALS
APPLICABLE ESPECIALLY FOR TESTING CEMENT'
وو
This Invention has for its object Improvements in apparatus for testing the
strength of materials applicable especially for testing Cement.
The two ends of the block or strip of material to be tested are as usual held in
two clips, one clip is secured to one end of a spring to which a rack is also
connected. The opposite end of the spring is secured to a bar which carries a dial
plate and a pointer upon the axis of which is a pinion gearing with the rack so
that the pointer is turned when the spring is extended and by gradually extending
the spring until the block of Cement breaks the strain which the block of Cement
will bear will be ascertained and recorded on the dial.
In testing the strength of materials more especially in testing Cement it is very
requisite that the strain should be brought to bear upon them at the same rate
and that the strain should not be brought to bear more rapidly upon one block or
strip of material than upon another and therefore to effect this that the spring
should be extended at one uniform rate each time that it is used for testing. This
I effect by employing for the purpose of putting the spring into tension another
spring of more than double the strength which is allowed only to extend the first
spring gradually at any predetermined rate.
For this purpose I connect the bar to which the weaker spring is attached to
the piston rod of a piston working in a cylinder filled with liquid. A passage is
provided from the end of the cylinder on one side of the piston to the end of the
cylinder on the opposite side of the piston. The stronger spring is placed in one

page_text: end of the cylinder or in other position to act upon the piston in opposition to the
weaker spring.
When the apparatus is to be used the piston is by the turning of a screw or by
other mechanism moved in a direction to compress or extend the stronger spring
and relieve the weaker spring of all tension upon it.
When the block of material to be tested has been secured at its two ends to the
two clamps the stronger spring is set free by turning the screw or other mechanism
in the reverse direction. The stronger spring then moves the piston away from
one end of the cylinder towards the other the rate at which it can do so being
controlled by the rate at which the liquid in the cylinder can pass from one end
of it to the other. As the piston noves gradually along the cylinder the opening
by which the liquid can pass from one end of the cylinder to the other is gradually
increased in area so that the rate of travel of the piston along the cylinder may be
approximately uniform-or its rate of travel can be regulated so that it shall take
place at any required speed.
In this way tension is placed gradually upon the weaker spring and so upon the
block or strip of material which is being tested.
In order that no strain may come upon the apparatus at the time when the
block of Cement breaks and the two clamps are suddenly drawn apart from one
another by the action of the spring I embrace the two clamps by a strong ring
which is loose around the clamps so long as the block remains unbroken but which
allows but a slight separating movement of the clamps when the block breaks.
The pointer geared with the rack is made to turn a second pointer which moves
around the spindle of the first pointer. When the block breakes and the first
pointer flies backwards the second pointer remains stationary and records the
pressure. At the same time a valve may be made to close and cut off communi-
cation between the two ends of the cylinder so that the position of the pointers
then remains unaltered.
In place of using hydraulic apparatus for controlling the action of the stronger
spring upon the weaker spring other ordinary equivalent mechanism might be
used for the purpose.
Apparatus constructed as above described may be made to occupy but a small
space and is more portable than other testing machines heretofore made. It can
be fitted in a small wooden box which when open may be secured by a clamp to
any table or mantelpiece.
The moulds and utensils used for making up blocks of cement in proper form for
being tested may be held in the box.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Porter in the Great Seal Patent Office on the 2nd November
1882.
WILLIAM PORTER of Manor Park Lee in the County of Kent Engineer.
IMPROVEMENTS IN APPARATUS FOR TESTING THE STRENGTH OF MATERIALS
APPLICABLE ESPECIALLY FOR TESTING CEMENT
"
This Invention has for its object improvements in apparatus for testing the
strength of materials applicable especially for testing cement.
The two ends of the block or strip of material to be tested are as usual held in
two clips one clip is secured to one end of a spring to which a rack is also
connected. The opposite end of the spring is secured to a slide which carries a
dial plate and a pointer upon the axis of which is a pinion gearing with the rack
so that the pointer is turned when the spring is extended and by gradually
extending the spring until the block of cement breaks the strain which the block
of cement will bear will be ascertained and recorded on the dial.
In testing the strength of materials more especially in testing cement it is very
requisite that the strain should be brought to bear upon them at the same rate
and that the strain should not be brought to bear more rapidly upon one block or
strip of material than upon another and therefore to effect this that the spring
should be extended at one uniform rate each time that it is used for testing. This
I effect by employing for the purpose of putting the spring into tension another
spring of more than double the strength which is allowed only to extend the first
spring gradually to any predetermined rate.
For this purpose I connect the bar to which the weaker spring is attached to the
piston rod of a piston working in a cylinder filled with liquid. A passage is
provided from the end of the cylinder on one side of the piston to the end of the
cylinder on the opposite side of the piston. The stronger spring is placed in one
end of the cylinder or in other position to act upon the piston in opposition to the
weaker spring.
When the apparatus is to be used the piston is by the turning of a screw or by
other mechanism moved in a direction to compress or extend the stronger spring
and relieve the weaker spring of all tension upon it.
When the block of material to be tested has been secured at its two ends to the
two clamps the stronger spring is set free by turning the screw or other mechanism
in the reverse direction. The stronger spring then moves the piston away from
one end of the cylinder towards the other the rate at which it can do so being
controlled by the rate at which the liquid in the cylinder can pass from one end of
it to the other.
As the piston moves gradually along the cylinder the opening by which the
liquid can pass from one end of the cylinder to the other is gradually increased in
area so that the rate of travel of the piston along the cylinder may be approxi-
mately uniform or its rate of travel can be regulated so that it shall take place at
any required speed.
In this way tension is placed gradually upon the weaker spring and so upon
the block or strip of material which is being tested.
In order that no strain may come upon the apparatus at the time when the
block of cement breaks and the two clamps are suddenly drawn apart from one
another by the action of the spring I embrace the two clamps by a strong ring
which is loose around the clamps so long as the block remains unbroken but
which allows but a slight separating movement of the clamps when the block
breaks.

page_text: The pointer geared with the rack is made to turn a second pointer which moves
around the spindle of the first pointer. When the block breaks and the first
pointer flies backwards the second pointer remains stationary and records the
pressure. At the same time a valve may be made to close and cut off communi-
cation between the two ends of the cylinder so that the position of the second
pointer then remains unaltered.
In place of using hydraulic apparatus for controlling the action of the stronger
spring upon the weaker spring other ordinary equivalent mechanism might be used
for the purpose.
Apparatus constructed as above described may be made to occupy but a small
space and is more portable than other testing machines heretofore made. It can
be fitted in a small wooden box which when open may be secured by a clamp to
any table or mantel piece.
The moulds and utensils used for making up blocks of cement in proper form
for being tested may be held in the box.
In order that my Invention may be fully understood I have in the Drawings
hereunto annexed shewn various views of an apparatus constructed as above
described.
Figure 1 is a vertical transverse section. Figure 2 a front view partly in section
and Figure 3 front view of the apparatus.
A B are the two clips which are to take hold of the two ends of a block of
cement C. The upper clip A is fixed to the frame D of the apparatus. The lower
clip has attached to it one end of a coiled spring E and also a toothed rack F.
The other end of tho spring is hooked over a stud or stump on a slide G which
can move up and down in guides H-this slide carries a dial plate I with a central
spindle J which has upon it a small toothed pinion which gears with the toothed
rack F the spindle carries the dial pointer and also a second loose pointer as before
mentioned.
K is a strong spring between an abutment D¹ forming part of the frame and a
flat surface on the slide G. It surrounds the spring E and in the drawing it is
shewn to be in compression.
It is compressed by two pairs of toggle levers L worked by a screw M and hand
wheel M as shewn. OO are two nuts into which the screw screws the portion
of the screw working in one nut is right handed the other working in the other
nut is left handed. Each nut is jointed by one link L to the slide G and by the
other to a fixed pin P which forms an abutment. Q is a piston rod extending
downwards from the slide its piston works in the hydraulic cylinder R. S is a
valve to allow liquid to pass freely from the top to bottom of the cylinder but not
in the opposite direction. T is a valve by which liquid can either be allowed to
pass from the bottom to the top of the cylinder or by which the passage of liquid
in that direction can be cut off. As shown at Figure 1 the passage by which the
liquid can pass from the bottom to the top of the piston is a tapering passage so
that as the piston descends in the cylinder the liquid may pass more and more
easily as a gradually less and less pressure is exerted upon the piston by the
spring.
In order that the valve may be closed immediately that any block of cement
being tested breaks a rod W is carried out through a stuffing box at the end of
the valve and is coupled to a lever X by which the rod can be moved to and fro to
open or close the valve a tail piece of this lever enters a slot in the stem of the
toothed rack F. So soon as a block of cement which is being tested breaks, the
spring E will contract the rack F will descend and the lever X will be moved and
the valve T will be lifted so as to close the passage leading to the upper part of
the cylinder the piston can therefore descend no further in the cylinder and the
slide G then remains at rest. When the rack descends as above described on the
breaking of a block of cement the pointer affixed to the spindle J flies back but
the loose pointer which previously it carried round by acting against a projection
U standing up from it remains at rest and indicates upon the dial the strain at

page_text: which the block C broke. As will be seen by the drawings the clips A and B are
both embraced by a loose band V which limits the extent to which the clips can
be drawn asunder when a block of cement breaks. By this means I prevent any
undue strain coming upon the parts of the apparatus on the breakage of a block of
cement.
In place of using single springs as above described, pairs of springs or sets of
springs of other number might be used.
Having thus described the nature of my Invention and the manner of performing
the same I would have it understood that I claim :-
First. The construction of apparatus for testing the strength of blocks of cement
or other material substantially as herein before described.
Second. The employment for putting a strain upon one or more springs used
for testing the strength of a block of material of other one or more springs in
conjunction with governing apparatus which controls the speed at which the strain
is put upon the first named one or more springs.
In witness whereof I the said William Porter have hereunto set my hand
and seal this thirty first day of October in the year of our Lord One
thousand eight hundred and eighty two
WILLIAM PORTER (L.S.)