Improvements in Machinery or Apparatus for Testing Canvas and other Materials.
Year: 1885

page_text: COMPLETE SPECIFICATION.
"
Improvements in Machinery or Apparatus for Testing Canvas
and other Materials.
I, JOHN FREDERICK O'CONNOR of 57 Avenue Marceau, Paris, France, Civil and
Mechanical Engineer, do hereby declare the nature of my said invention for
IMPROVEMENTS IN MACHINERY OR APPARATUS FOR TESTING CANVAS AND OTHER
MATERIALS and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
"
A method heretofore adopted in testing the tensile strength of canvas, both
lengthwise and crosswise, has been to cut off a strip of material an inch, or an inch
and a half in width, and to put this strip in a machine which would indicate the
final stress on the material. Nothing much wider than an inch and a half could
be tested owing to the construction of the machines.
It is obvious that by cutting such material into small pieces the texture of each
specimen to be tested, is more or less destroyed, and consequently, the final strain
is reduced; and this would happen more especially with such a heterogeneous
material as canvas.
It will also be apparent that if a piece of canvas say 24 inches wide be cut into
24 strips and each strip be tested separately, the final strains will not aggregate as
much as the whole width, tested at once. In the latter case there are the two
Belvage edges of the material to increase its strength. Furthermore, it is a more
practical test for the canvas, to test it without cutting it.
Now the object of my invention is to provide a machine adapted to receive and
test a piece of canvas of full width.
For this purpose I employ two grippers adapted to take hold of opposite ends of
a piece of canvas, and to hold the same uniformly throughout its width. These
grippers are movable along stationary tracks or ways provided in the machine, and
with one gripper is connected a hydraulic cylinder and piston whereby a pulling
force may be exerted on the fabric. With the other gripper is connected a beam
or bell-crank lever, the long arm of which is connected with a steelyard-beam, and
on the said steelyard-beam is a weighted trolley or carriage, which is moved along
the beam by well known mechanism.
This invention comprises a novel combination of parts, hereinafter described,
also an adjustable connection between the main beam and the gripper, which is
attached thereto, whereby the machine is adapted for testing pieces of canvas of

page_text: different lengths; and it also includes a novel construction of gripper, which
I prefer to employ at each end of the piece of canvas, and which is hereinafter
described.
In the accompanying two sheets of illustrative drawings Fig. 1 is a side elevation
of a machine according to my invention. Fig. 2 is an end elevation taken from
that end of the machine at which the hydraulic cylinder is fixed. Fig. 3 is a plan.
Fig. 4 is a longitudinal section, taken in the line x. x, Fig. 5, illustrating to a larger
scale the adjustable connection between the beam and its attached gripper, and
Fig. 5 is a plan of the saine. Fig. 6 is an end elevation partly in section on the
line y. y Fig. 5. Fig. 7 is a side elevation of the gripper attached to the beam
with portions of its supporting ways or tracks, and Fig. 8 is a part end view
thereof, its supporting tracks being in section.
The same letters of reference designate the same or corresponding parts in all the
figures.
A. A designate the end frames of the machine, which are connected by
longitudinal cast iron beams or stretchers A*, so as to form a stable and secure
framing.
At each side of the machine are longitudinal tracks or ways a, which support
two grippers B. B', and on which the said grippers may slide or move.
These
grippers are preferably supported by or provided with friction wheels or rollers,
and their construction will be more particularly described hereafter.
At the left-hand end of the machine, as shown in Fig. 1, is a hydraulic cylinder, C,
which is to be supplied with water through a pipe, b, from any suitable pump, (not
shown,) and from the outer end of this cylinder projects a piston or plunger, C¹,
which is connected by links or rods c with a bail or cross piece, c', connected to the
gripper B by knife-edge pivots c² fixed to the frame of the gripper, and when the
piston or plunger is forced outward from the cylinder the gripper B is pulled
toward that end of the machine. At the opposite end of the machine is supported,
by knife-edge bearings or pivots d the main beam D, which constitutes a bell-crank
lever, and is composed of a straight plate or piece extending longitudinally of
the machine at one side thereof and a bent plate, D¹, united thereto, as shown in
Fig. 3.
At the end of the machine at which is the hydraulic cylinder C is pivotted a
steelyard-beam, E. This steelyard-beam also has knife-edge bearings or pivots e,
and is connected at a point very near its fulcrum by a rod, E¹, with the end of the
main beam D.
On the steelyard-beam E is mounted a running or movable trolley, f, from which
is suspended a weight, f, and to which is connected an endless belt or chain f²,
carried by suitable small wheels, ƒ*, and capable of being moved by a suitable
hand-wheel, f³.
The means for moving the trolley and its weight along the beam E in themselves
form no part of my invention, and no further description thereof is needed. f' is
a counter-weight, which counter-balances the main lever D and all parts of the
lever mechanism.
As before stated, the main beam D constitutes a bell-crank lever and the devices
connecting the shorter arm thereof with the gripper B¹ are best shown in Figs. 4,
5, and 6 Sheet 2.
To the frame of the gripper B¹ is attached, by means of knife-edge bearings or
otherwise, a bail or bar g, to which are secured two screws, g', extending rearward
and parallel with each other. These screws g' extend through a box or hollow
frame, h, to which arms or links h¹ are connected and project rearward, as shown in
Fig. 5. The arms or links h¹ are connected by knife-edge or other pivots or bearings
with a cross pin or bar, i, secured in the plates forming the beam D D', and are
therefore connected with the short arm of the said beam or lever.
In the box or frame h are journaled spur pinions j.j which constitute nuts fitting
the screws g g¹, and an intermediate spur-wheel, j', which engages with said
pinions j, so as to insure their rotation in the same directions and simultaneously...

page_text: In the box or frame is also journaled a bevel-pinion, 2, gearing with a bevel
wheel formed on or fixed to the journal of one of the pinions ; and capable of
being turned by a hand-wheel jt. When the pinion is turned, the pinions j are
both turned upon the non-rotary screws gl in the same directions, and thereby the
connection between the gripper B and the short arm of the beam D may be
shortened or lengthened to adapt the machine for a longer or shorter piece of
canvas.
The construction of the grippers forms an important feature of my invention,
and is illustrated most clearly in Figs. 4, 5, 7, and 8.
A description of one gripper applies to both. Each gripper consists, essentially,
of three rollers, 1 lm, and their connections. The rollers are preferably hollow, and
have shafts extending through them, or are provided with journals at their ends.
At each end of the rollers are end frames; o, which may be of any suitable form,
and in these frames the journals of the rollers k and are held in fixed bearings,
the said rollers being keyed so that they cannot turn and the roller having its
lower portion cut out so as to fit roller m when the strain is on the material as
shewn in Figs. 4 and 7. The roller m is fitted to boxes m' which are capable of.
sliding in vertical slots o¹ in the frames o. The canvas s is passed over the roller k,
under the roller m; and thence upward and partly around the roller 1, to which it
is secured across the entire width of the canvas by a clamp s¹, or other means.
When strain comes upon the canvas, it pulls the roller m toward the roller 6, the
movement of the boxes m¹ in the slots o¹ providing for such movement, and the
pull of the canvas also rotates the roller m. Roller m is previously allowed to
rotate, in order that the canvas may settle evenly.
The stronger the tendency of the roller m to turn, the greater will be the bite of
the roller upon the top of the roller m, and hence the greater will be the resistance
opposed to the rotation of the roller m.
The rollers may be provided in their ends with holes t, in which a bar or handle
may be inserted for turning them.
Not only is the grip produced as described very secure, but another great
advantage of the arrangement is that when strain is removed from a piece of
canvas the rollers are left free, and the detachment of the canvas from the gripper
is easy.
The roller may have a flattened portion, to facilitate the introduction of the
canvas between the rollers k, land over the former.
When a piece of canvas has been secured by the grippers, the trolley and running
weight are adjusted on the steelyard-beam E to produce the desired strain on the
canvas. If the canvas is strong enough to resist the test-strain, then the trolley
and running weights are moved outward, and strain is applied until the canvas
tears. The position of the trolley and running weight will then determine the
tearing-strain.
Although more particularly intended for testing canvas, my improved machine
may also be employed for testing other fabrics and leather.
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
1 claim is
1. In machinery or apparatus for testing canvas and other materials, the
combination, with a main frame and two grippers B. B¹, in which opposite ends of
a piece of fabric may be secured, of a cylinder and piston at one end of the frame,
connected with the gripper B, for putting strain on the fabric, the beam D, pivotted
at the other end of the frame, adjustable connections between the gripper B¹ and
the beam for adjusting the gripper to suit fabrics of different lengths, the steelyard-
beam E, and the rod E, connecting the beams D and E, the weighted trolley f and
connections for moving it, substantially as herein described.
2. The combination, with the gripper B and an actuating-cylinder and piston
connected therewith, of the gripper B', the non-rotary screws g¹, extending there-

page_text: from, the beam D, the movable box or frame h, and arms or links h³, connecting it
with said beam, the spur-pinions j, forming nuts fitting said screws, and one
provided with bevel-teeth, the intermediate wheel, j¹, and the operating pinion and
handle j, j all substantially as herein described.
3. The combination, with the gripper-frame, of a roller, k, journaled therein,
a roller, m, around which a fabric is to be passed, and a roller, l, to which the end
of the fabric is to be clamped the journals of the roller m sliding in vertical slots o¹
when strain is put upon the material to be tested which passes around the roller m
so that the said roller m will be drawn up and caused to bite against the roller
by any rotation of the former, substantially as herein described.
4. The combination, with the gripper frame provided with vertical slots o¹, of the
roller k, journaled in said frame, the roller m, having boxes movable in said slots,
and the roller , provided with a clamp for the fabric, all substantially as herein
described.
Lastly. I claim the combination of parts constituting the improved machine for
testing canvas and other materials constructed arranged and operating substantially
as hereinabove described with reference to and illustrated in the accompanying
drawings.