Improvements in Friction Testing Machines.
Year: 1899

page_text: Date of Application, 12th July, 1899-Accepted, 12th Aug.,
1899
COMPLETE SPECIFICATION.
Improvements in Friction Testing Machines.
I, JOHN GOODMAN, Professor of Engineering at the Yorkshire College of the
Victoria University, in the City of Leeds, 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 refers to that class of testing machines used for testing the friction
between axles or journals and the like and their bearings and for analogous pur-
poses, and consists of an adjustable spring device or lever and weight device
for putting any desired pressure or load on the bearing, in a truly vertical
direction, and a dynamometer device for estimating the friction.
of a
link to
one
end
fixed
to a
A testing machine constructed in accordance with my invention comprises
a stirrup or horse shoe shaped bracket, hereinafter referred to as the "stirrup
in which provison is made for receiving the bearing or block of metal to be tested.
Two arms
the stirrup respectively,
are attached to opposite ends of
with
in line
each other, and with the
preferably with their axes
The shorter
centre of the axle or journal on which the bearing rests.
of these arms carries a balance weight, and the end of the longer arm is attached
by means
end of a spring contained in a
spring case; the opposite
of the spring being connected
screw passing through the end of the spring case. A pointer attached to the lower
end of the spring or the upper end of the screw and a graduated scale on
the spring case serve to indicate the compression or tension of the spring. The
scale is preferably so graduated as to give directly the friction on the axle. A
spirit level is attached to one side of the stirrup to indicate when the axis of the
arms is horizontal, or more strictly when the knife edge of the fulcrum referred
to is truly vertically beneath the centre of the axle. A hole is formed through
the centre of the bridge of the stirrup, to admit of the insertion of a thermometer,
for the purpose of observing the temperature of the bearing during tests.
The lower part or horizontal cross part of the stirrup is formed of two side
From this
pieces, in which are fitted the ends of a steel knife edge fulcrum.
fulcrum a long rod, hereinafter termed the load road, is suspended.
Standards for carrying the bearings for the axle are mounted on the frame
of the machine, within which is situated a strong spiral spring, hereinafter
referred to as the load spring; by the compression or tension of which, the load
is applied to the bearing to be tested. Or the load may be applied directly, or
through lever mechanism. When a spring or lever mechanism is used, a scale
and pointer are provided so that the load applied to the bearing can be read
off directly.
And in order that my invention and the manner in which the same is to be
performed may be more readily and clearly understood, I have annexed hereto
the accompanying drawing of a friction testing machine constructed in accordance
with my invention.
Fig. 1 is a vertical section of the same, and Fig. 2 a cross section through

page_text: A A indicate the vertical frames of the machine.
Bindicates the top plate of the frame, the right hand side of which only is
shewn in section.
a b indicates the stirrup casting, the part a forming the arch or bridge, and
being the bottom horizontal side pieces.
c is the axle or journal, on which rests the bearing block d. The shaft or
journal c is formed hollow, to permit of water being passed through it to cool the
shaft or journal, when desired, or necessary.
C
e is a thermometer, inserted in a hole formed in the centre of the arch or
bridge a to receive it.
h is a balance weight, and is a link attached by a pin joint to the outer
end of the long arm g.
One end of the link is attached to a spring, contained
in the spring case m, which latter is rigidly attached to the frame of the machine.
The opposite end of the spring is connected to the adjusting screw n, to which
the pointer is attached.
o is a spirit level attached to the side of the stirrup bridge a, to indicate
when the knife edge of the fulcrum (i.e. the pull) is truly vertically beneath the
centre of the axle c.
p is a knife-edge fulcrum, the ends of which are rigidly fixed in the side
pieces of the stirrup.
q is one of the side standards, carrying the bearings for the shaft or journal c.
is the hollow cylindrical head of the load rod s, embracing and supported
on the knife edge of the fulcrum p; and t is a plate, attached to the lower end
of the rod s, and bearing against the underside of the load spring u. v is a
graduated bar or scale attached to the bottom spring plate t.
w is a square threaded nut, fitted in a vertical bearing in the top plate B of
the frame; and provided on the outside below the bearing with a worm wheel a.
y is a worm fitted on the shaft z, and gearing with the worm wheel x.
In place of the worm and worm wheel toothed gearing may be employed.
1 is the hollow square threaded screw fitting in the nut w, and carrying at
its lower end a plate 2; which bears upon the top of the load spring u. The
load rod s passes down through the hollow part of the screw 1. 3 is a road
depending from the plate 2, and carrying a socket piece 4 at its lower end,
through which the scale bar v slides. The tendency of the screw 1 to rotate with
the nut w may be prevented by side wings on the top plate fitting in corre-
sponding guides formed in the side frames of the machine, and indicated by
dotted lines 5 in Fig. 1.
The bar scale v is so graduated, that the reading opposite the top edge of the
socket 4 indicates the compression load of the spring u.
The method of using the machine is as follows:-
After the bearing block d to be tested has been secured in position in the
bridge or arch a of the stirrup, the shaft z is rotated to compress the load spring u,
until the top edge of the socket piece 4 is opposite the reading indicating the
desired load.
The shaft or journal c can now be rotated. As the friction between the bear-
ing block d and the shaft or journal c tends to tilt the stirrup and arms to one
side, this is counteracted by moving the screw n, until the spirit level o indicates
that the load or pull is acting truly vertically, the reading thereby obtained from
the pointer gives the friction on the axle under the load indicated for the time
being by the load spring scale v.
It will be evident that the load on the axle may be given by an extension
instead of compression of the spring. For example this may be done by rotating
the nut w in the opposite direction, or by connecting the plate t to the screw 1
and the plate 2 to the load rod s.
Also in place of the nut or screw device shewn, the tension or compression of
the load spring may be effected by means of a lever, and lastly the load may be
applied to the load rods directly, or by means of a sliding weight and lever.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:―
1. In testing machines such as are herein referred to the use of a stirrup or
horse shoe shaped device arranged to receive the bearing to be tested in the arch
or bridge portion and carrying a knife edge fulcrum between the bottom sides
from which fulcrum the test load is suspended substantially as herein set forth.
2. In testing machines such as are herein referred to the combination with a
stirrup or horse shoe shaped device carrying the bearing to be tested in the arch
or bridge portion and a knife edge fulcrum for carrying the test load between
the bottom sides, of a balanced dynamometer lever and adjustable spring and
indicator device for indicating the friction on the axle substantially as herein
set forth.
3. The combination with the subject matter of Claims 1 and 2 of means for
applying an adjustable load or pull to said knife edge fulcrum substantially as
herein set forth.
4. In testing machines such as are herein referred to the combination of a
stirrup or horse shoe shaped bracket arranged to receive the bearing to be tested
in the arch or bridge portion with a knife edge fulcrum for carrying the test
load attached to the lower horizontal sides of the bracket so that the knife edge
and the centre line of the axle are in the same plane and with a spirit level
attached to the bracket and adjusted to indicate accurately when the plane of the
knife edge and the centre line of the axle is vertical substantially as set forth.
5. In testing machines such as are herein referred to the combination of load
spring u toothed wheel a nut w screw 1 and load rod s for the purpose of adjusting
and transmitting the test load or pull to the fulcrum 2 substantially as set forth.
6. The general arrangement construction and combination of the parts con-
stituting my improved testing machine substantially as herein set forth and
illustrated in the accompanying drawings.
Dated this 10th dow of T.1., 1900
J. CLARK JEFFERSON,
30, Park Row, Leeds, Agent for Applicant.