Improvements in and connected with Tables for Grinding, Smoothing, and Polishing Plate or Sheet Glass.
Year: 1892

page_text: Date of Application, 21st June, 1892-Accepted, 27th Aug., 1892
COMPLETE SPECIFICATION.
Improvements in and connected with Tables for Grinding, Smoothing,
and Polishing Plate or Sheet Glass.
I,GEORGE AUGUSTUS MARSH, Junior, of No.816 Adams Street, City of Sandusky,
County of Erie, and State of Ohio, one of the United States of America,
Engineer. 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 and accompanying drawings
--
This invention has for its object to provide an improved means for holding plates
or sheets of glass upon glass grinding, smoothing or polishing tables by a vacuum
or atmospheric pressure. And the invention relates more particularly to the table;
said table being provided on its top with a multiplicity of cells which are located
in close proximity to each other, the cells in the table top communicating with a
chamber located within the table, which chamber and cells are suitably connected
with air exhaust mechanism for producing a vacuum in the cells, so that when
the glass is placed on the table and the air exhausted the sheets or plates of glass
will be held in place. The table is also provided with liquid channels or passages
which are connected with a liquid chamber located within the table adjacent to its
upper surface, said liquid chamber serving to regulate the temperature of the
table and glass placed thereon, and also serving as a means for supplying liquid
to a packing upon which the glass directly rests. The invention further embodies
the employment of mechanism for moving the table, placing the glass thereon and
removing it therefrom, and in the arrangement of pipes or conduits which are
attached to the table and connect the chambers therein with air exhaust mechanism
and with a liquid supply; the above means being designed to dispense with the
use of plaster for retaining the plates or sheets of glass upon the table, and which
at the same time greatly facilitate and quicken the operation of grinding and
polishing glass.
In the accompanying drawings
―
Figure 1 is a side elevation of a glass grinding, smoothing or polishing table
constructed in accordance with the invention, the same being designed for holding
small plates or sheets of glass.
Fig. is a side elevation, partly in section, of a different structure intended to
receive much larger plates or sheets of glass.
Fig. 2 is a detail sectional view of the box and packing which receives the
water supply pipe.
Fig. 3 is a detail sectional view of the supporting shaft, showing the packing for
the air and water supply pipes and means for supporting the frame of the table on
said shaft.
Fig. 4 is a plan view of the support for the table shown in Fig. 1.
Fig. 5 is a detail sectional view of a portion of the table top upon which the
glass directly rests, showing the connections of the air and water pipes.
Fig. 6 is a sectional perspective view of a section of the table top.
Fig. 7 is a perspective sectional view of a section of the table top showing the
packing and glass placed thereon.
Fig. 8 is a perspective view showing bars employed to place the glass upon and
remove it from the table.
Fig. 9 is a detail view of an absorbent packing used in connection with the
table, and
Fig. 10 is a sectional view of a plug which is used to cut off sections of
the table.
A designates the sections which make up the top of the table upon which the

page_text: glass to be operated upon is placed; a number of sections being used accord-
ing to the size of the table. The sections consist of an upper plate having
raised walls a, some of which are arranged in pairs to provide water channels
as shown in Figs. 5 and 7; water chaunels being also arranged around
the margin of each section, as shown in Fig. 5. These raised. walls form
supports and divide the top of each section into a multiplicity of cells which are
in comparative close proximity to each other; and each section or cell is con-
nected by apertures with each other and with outlets leading to a vacuum
chamber B formed in the lower portion of each section. Where water channels
surround the cells as in Fig. 7 the connecting apertures shown in Fig. 6
through the raised walls a, do not exist but each cell is connected with the
vacuum chamber B by an independent opening m. The sections A are divided
into vacuum and water chambers by a plate on each side of which is placed a
suitable packing C₁, and the parts are bolted together and are connected by
adjusting screws d to the upper portion of the supporting frame D.
When a
large table is desired the requisite number of sections are secured to the support D
so that there will be a space of the required size between the sections transversely
across the table, and resting on the support D are bars E to which are connected
movable bars F which lie when lowered on the same line as the raised walls a
of the sections. These bars F may be covered on their upper edges with a
suitable material and connected to each other by an ordinary rock shaft so that
they can be raised and lowered in unison; and when it is desired to place plates
of glass upon the table the bars F are raised and the glass placed thereon before
being lowered. The glass is also raised from the table by means of these bars after
it has been ground or polished.
Ր
The apertures in the upper part of the sections A connect with the vacuum
chamber B, and said sections are connected by a pipe & to pipes & having check
valves as shown in Fig. 5, said pipes 62 extending to the supporting shaft G,
which is hollow, the lower end of said shaft being connected to the pipe B* which
leads to the air exhaust mechanism. When the air is exhausted from the hollow
supporting shaft it will be exhausted from the chamber B and from the cells in
the table top when the glass is properly placed thereon.
C designates a liquid chamber arranged in each of the sections A, and said liquid
chamber connects with the channels a* between the raised walls a a of the table
top by means of apertures a². This liquid chamber is connected by suitable
pipes c to a water supply pipe C2 which passes through the hollow shaft G so that
liquid can be supplied to the chamber C and from thence to the channels in the
table top. This liquid supply provides means for moistening the packing which
is placed above the water channels in the table top and rests on the raised walls a;
which packing is made of a suitable absorbent material, as paper pulp, and is
reticulated to rest upon the raised walls. The liquid supply also regulates the
temperature of the table top and absorbs heat generated by friction in grinding
or polishing the glass, or said liquid when heated will heat the top of the table
and glass to give it the proper temperature to start the grinding or polishing
process at once.
The table made up of the sections A and support therefor is mounted on a hollow
shaft G having a gear-wheel I to which a rotary motion is imparted. The motor,
preferably a steam-engine, has a cut-off valve, L, located in the steam pipe K,
which cut-off valve is operated so that at any time should the vacuum which
retains the glass upon the table be destroyed the steam supply will be cut off from
the engine and the brake M be caused to engage with the driving shaft N, so as to
stop the rotation of the table and thus prevent the glass being thrown therefrom
by centrifugal force.
When it is desired to grind, smooth or polish plates or sheets of glass with the
mechanism herein before described a packing of paper pulp or other absorbent
material is placed upon the top of the table and the plates of glass to be operated
upon are placed on said packing. Should any of the plates of glass be of less

page_text: thickness than the adjacent plates, one or more sheets of paper, as indicated by h
Fig. 7, may be placed under the thinner plates to bring the upper surfaces of all
the plates on the same level. After or before the plates of glass have been placed
upon the table liquid is admitted into the chamber C through the pipe Cx, which
liquid will moisten the packing, and with the glass convert the top of the table into
a large number of cells, the raised walls thereof being in close proximity to each
other will prevent the glass being bent by the atmospheric pressure when the air
is exhausted beneath the glass. When the plates of glass have been placed upon the
table all at the same level the air is exhausted from the chamber B, and where
the edges of the glass join, the cells of the adjacent sections can be shut off from
the vacuum chamber B by means of plugs O which are inserted in the apertures b.
A constant supply of liquid is kept up when the table is in operation, and it is
obvious that any excess of liquid which finds its way through the packing will be
drawn by the air exhausting mechanism into the air exhaust pipe x, and if there
is any grit or foreign substance it will be caught by the trap of the pipe. The
table is rotated at the required degree of speed, and when the glass is being ground,
smoothed or polished should the vacuum at any time be lost the driving motor will
be automatically stopped and the check valve 3 between the pipes and 62 will
hold the vacuum in the chamber B. After the plates have been ground and polished
the vacuum may be released by stopping the vacuum pumps when the plates of
glass can be removed from the table.
,
I do not claim per se the use of atmospheric pressure for fixing sheets or slabs of
glass on tables.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim, is :-
:-
1. A glass holding table having air and water chambers, a shaft having an air
duct which communicates with air exhaust mechanism and with the table and vacuum
cells thereon, whereby a plate or plates of glass is held on the table by a vacuum,
for the purpose set forth.
2. A glass holding table having a multiplicity of cells or recesses in its top,
channels surrounding the same, a liquid supply connected with said channels, and
an air pipe connected with the cells in the table top, the above being designed for
use with a suitable packing to retain glass on the table when air is exhausted from
the cells.
3. In a hollow glass holding table having an upper plate with raised walls and
apertures, channels for a liquid supply, a liquid supply connected with said channels,
means for exhausting the air from the table, and a packing adapted to rest upon
the raised walls of the table so as to provide with the glass and packing a vacuum
chamber the raised supports therein being in close proximity to each other,
substantially as set forth.
4. In combination with a hollow glass supporting table having vacuum cells, an
air exhaust pipe and a water supply connected therewith so that liquid can be
conveyed to the cells, for the purpose set forth.
5. A glass holding table made up of a series of hollow sections supported so
that the upper surfaces thereof will be on the same plane, each section having
when the glass and packing are placed thereon a number of vacuum cells, said
cells being connected with air exhaust mechanism and with a liquid supply, the
packing being of an absorbent nature, substantially as shown, and for the purpose
set forth.
6. In a glass grinding or polishing machine, the combination of a series of hollow
sections supported to form a table top, a hollow standard connected therewith, said
standard being connected by means of pipes to the table top, a water supply, pipe
passed through said standard and connected with the table top, air exhaust
mechanisin communicating with the hollow standard, and driving mechanism for
rotating the table and standard, for the purpose set forth.

page_text: 7. In combination with a revoluble grinding table upon which the glass plates to
be ground are held by the vacuum or air exhaust, a motor for turning said table,
an air exhaust mechanism connected to the table, a brake and power supply
mechanism adapted to be automatically operated when the vacuum is lost in the
table so as to cause the stoppage of the motor and operate a brake on the driving
shaft which revolves the table, substantially as shown, and for the purpose set
forth.
8. In combination with a glass holding table having a top with a series of
apertures or vacuum cells with raised walls in close proximity to each other forming
water channels, and an absorbent packing adapted to lie over the walls and water
channels, for the purpose set forth.
9. In a glass holding table having spaces in its upper surface, bars adapted to lie
within said spaces, said bars being adapted to be raised or lowered, for the purpose
set forth.
10. In combination with a table for grinding or polishing glass, sections divided
horizontally into compartments, the upper compartment being a liquid receiving
chamber and the lower compartment a vacuum chamber which is connected by
apertures with the table top, substantially as shown, and for the purpose set forth.
11. In a grinding or polishing table for glass, the combination of a table having
a surface which provides a multiplicity of cells when the glass is placed thereon,
said cells connecting with an air chamber and a chamber for circulating liquid in
the table, and apertures for conveying said liquid to a packing upon which the glass
rests, for the purpose set forth.
12. The combination in a glass grinding or polishing table having an air chamber
and liquid supply chamber therein, the top of said table having parallel raised walls
with apertures which communicate with the liquid supply, supports which project
to the same height as the walls having liquid channels, and cells communicating
with the air chamber of the table top, for the purpose set forth.
Dated the 20th day of June 1892.
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.