Improvements in Machines for Grinding Glass Tubes.
Year: 1897

page_text: Date of Application, 4th May, 1897-Accepted, 4th Dec., 1897
COMPLETE SPECIFICATION.
Improvements in Machines for Grinding Glass Tubes.
We, THEODORE W. VAN HOESEN, and WALTER W. WILSON, both of Troy in
the State of New York in the United States of America, Clerks, do hereby declare
the nature of this invention and in what manner the same is to be performed
to be perticularly described and ascertained in and by the following statement:-
Our invention relates to machines for grinding the interior surface of a glass
tube; and the object of our invention is to provide a machine for grinding the
interior of a spirit level glass at the portion thereof within the limits of the
movements of the bulb, and so ground that the difference in the thickness of the
glass shall be proportioned after grinding equally from the centre of the tube.
We attain this object by means of the mechanism illustrated in the accom-
panying drawings, in which:-
Fig. 1 is a front elevation.
Fig. 2 is a section along the line 1-1 on Fig. 1.
Fig. 3 is a section along the line 2-2 on Fig. 1.
Fig. 4 is a section along the line 3-3 on Fig. 3.
Fig. 5 is a detail view of the adjusting plate.
Fig. 6 is a sectional view of the tube carrier.
Fig. 7 is a cross section along the line 4-4 on Fig. 6.
Fig. 8 is an end view of the collar.
Fig. 9 is a sectional view of the collar.
Fig. 10 is a sectional view of the tube after being ground.
Fig. 11 shows a modified form of the carrier. Fig. 12 is an end elevation of
the modified carrier.
Fig. 13 is a view of the upper portion of the modified carrier shown in Fig. 11.
Fig. 14 is a view of the lower portion of the modified carrier shown in Fig. 11.
Fig. 15 shows a modified form of securing the tube in position, and
Fig. 16 is a section of Fig. 15.
Similar letters refer to similar parts throughout the several views.
In order that a spirit-level tube shall be sensitive and adapted for use prac-
tically on mechanical instruments, it is necessary that the interior of the tube
should at the center be larger in diameter than points more remote from the
center and that the glass forming the tube should be ground smooth and gradually
grow thicker in minute degrees, in order that the bulb may pass readily from the
center toward each end as the level is raised or lowered, and so constructed that
by the position of the bulb in the tube, the degree in which the tube is out of
horizontal, can be accurately determined.
One means of accomplishing this result is that described in the drawings.
The frame consisting of the uprights A and top cross piece B, is suitably secured
to the floor and provided on the top of the cross piece B with pulleys C, upon
which the rope carrying the weight W at one end and outside of the frame,
the other end of said rope being attached to a block D, said block D adapted_to
be raised or lowered between the uprights A A and steadied in its movement by

page_text: the protruding pointed tongues EE fitting within suitable grooves e on the
interior surface of each of the uprights A A, as shown in Fig. 3; the tongue E
adjusted by means of the bolts ee. The block D is secured to the adjustable
plate F, having depending therefrom, the carriers f f and provided with the
elongated slots F F adapted to engage with the thumb screws G.G, which
thumb screws pass into the bottom of the block D. The position of the plate F
being thus capable of adjustment and the plate capable of being removed from
the bottom of the block without changing the position of the block.
The tube carrier H is secured to the plate I by means of the bolt y passing
through the hanger f on the plate F and the collar g'; tlius providing for the
oscillating movement of the tube carrier about said bolt.
The tube carrier H has inserted in each end thereof, à slitted collar J, shown
in Figs. 8 and 9, and within the collar J is placed a rubber ring j, all so arranged
and adjusted that the tube shall be held in position by the contraction of the
collar and rubber; thus supporting the tube rigidly by the exertion of a constant
pressure against all sides of the tube simultaneously.
The tube carrier H is also slotted and is provided near each end with lips hh,
one on each side of the slot, which may be drawn together by means of the
screw I, shown in Fig. 7, thus contracting the carrier, the collar and the rubber-
ring.
The grinding rod K, which is slightly curved, is passed through the tube T
when it is in position in the carrier and attached at each end to a suitablo
link which is attached cach to an arm L L. The arms L L are joined at
their ends with a suitable shaft mounted within the uprights A A and operated
by a lever M, connecting bar N and power wheel Q, or in any suitable manner.
As thus arranged, the notion of the arms L L will cause the rod K to reciprocate
within the tube T and in making its movement, will cause the tube carrier to
be raised, when the arm. L approaches the center and this movement of the tube
carrier is assisted by the compensating weight. W acting upon the block D, to
which the carrier is secured. The same movement of the arms L and the rod K
carried by them, causes the tube carrier and therefore the tube T to describe the
arc of a circle in its movement; thus oscillating the carrier upon the bolt
When the arms have moved to their extremity, the position occupied will be
that represented by dotted lines in Fig. 2..
For the purpose of grinding the tubes so that a section of the tube after
grinding, is circular, the tube is turned with the fingers, after it is ground a
short time in one position. The clamping screw may be loosened and the tube
revolved on the rod while the machine is running; thus revolving the tube with
the fingers, will cause all of the ridges and marks on the tube to disappear and
make the tube of equal value all the way round.
It will be noticed that this movement of the rods and the tube causes an action
upon the interior surface of the tube by the rod in the form of an arc of a circle,
of which the center or tangential point will be the center of the tube, and the
operation of the rod being fixed definitely and positively, the points of contact
will be the same throughout its whole length, so that the difference in the diameter 4
of the tube when completed, will be equal on each side of the center.
In order to provide for the different lengths of tubes and therefore of rods
necessary, we show in Fig. 2, a means for adjusting the angle made by the
arms L to each other by the use of the holders m m with two sets of bolt eyes nn,
making a very common and ordinary adjustment.
A modified form of carrier is shown in the figures on the third page of the
drawings. This is for the purpose of providing for different sizes of tubes, where
the difference is too great to be provided for by the slotted holder already described.
Thus, the holder is formed in two sections, upper 20 and lower 21, providing
for the upper a V-shaped plate 20, or two plates secured together in the manner 5.
shown in Fig. 12, which comes in contact with the tube T: The lower portion
is, provided with overlapping surfaces on each side, which clasp the sides of the

page_text: plate 20 and by means of a semi-circular clamping piece 23, provided with a
rubber disk 22, actuated by a screw 24 passing through the upper portion of the
plate 21, the V-shaped plate 20 and the lower plate 21 may be drawn toward
each other and the tube held securely between them, as shown in Fig. 12.
Fig. 16 shows a modified form of clasp for engaging with the end of the rod K,
it being apparent that the V-shaped block 25 operated by the screw 26 within the
elongated space 27, will allow for the insertion and adjustment of any size rod
required.
In the foregoing, has been shown a means for constructing a spirit-level tube
peculiarly adapted for use in the adjustment of mechanical instruments, in which
the horizontal and perpendicular are required to be adjusted to great nicety;
but we do not limit ourselves to the particular construction of the carrier or
means for imparting motion to the grinding rod, as the construction of a glass
tube, in which the center differs in diameter from every other portion of the
tube and has its adjacent parts differing in a gradual pre-determined and slight
degree, is the essence of our invention, and may be accomplished by modifications
o the parts of our machine, but which are equivalents thereof.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1st. A machine for grinding glass tubes, consisting of a tube carrier, a grinding
rod, an arm connected with said grinding rod, a means for imparting motion to
said arm, causing said grinding rod to reciprocate through a glass tube in said
carrier in the path of an arc of a circle, grinding the interier of the tube in such
a manner that midway between the ends of the tube, the diameter will be greater
than at any other portion of the tube, its adjacent parts differing is a gradual
pre-determined slight degree, substantially as described and for the purpose set
forth.
2nd. In a machine for grinding glass tubes, a tube carrier, a pivoted connection
between said carrier and a suitable hanger, a compensating weight connected
with said hauger, a frame within which said hanger is adjusted, a rod connected
by arms, a means for putting said arms in motion, causing said rod to reciprocate
within a tube placed in the carrier, substantially as described and for the purpose
set forth.
3rd. In a machine for grinding tubes, a tube carrier consisting of two parts,
the upper of said parts provided with a V-shaped opening adapted to engage
with a tube, the lower of said parts provided with upwardly extending arms
adapted to engage with the sides of the upper of said parts, a clamping plate
and screw arranged to engage with a tube placed within said opening, said
carrier mounted within a frame capable of vertical and oscillating motion, with
a grinding rod passing through a tube placed in said carrier, with a means for
imparting reciprocal motion to said rod, substantially as described and for the
purpose set forth.
ד
100
HERBERT HADDAN & Co.,
Agents to Applicants, 18 Buckingham Street Strand London.