IMPROVEMENTS IN EXTENDING TABLES, APPLICABLE ALSO TO PLATFORMS, GANGWAYS, OR DRAWBRIDGES, BLINDS, AND SCREENS
Year: 1879

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN EXTENDING TABLES, APPLICABLE ALSO TO PLATFORMS, GANGWAYS, OR
DRAWBRIDGES, BLINDS, AND SCREENS." A communication from abroad by
John Degroat Brassington, of the City, County, and State of New York,
United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 25th November 1879.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN EXTENDING TABLES, APPLICABLE ALSO TO
PLATFORMS, GANGWAYS, OR DRAWBRIDGES, BLINDS, AND SCREENS." [A comì-
munication from abroad by John Degroat Brassington, of the City, County, and
State of New York, United States of America.]
This Invention aims mainly to provide an extension table in which the extending
sections of the top shall be contained within the table and automatically presented
in proper place when the table is pulled out or extended, thus obviating the
objection of keeping the sections separate from the table and inserting them by
hand, and thereby forming an extension table which is complete in itself. To this
end the Invention may be briefly stated to consist in a table or its equivalent
constructed with a lazy tongs connecting its leg ends, and arranged with its width
vertical, with its upper terminals pivoted, and its lower terminals capable of sliding
and having its alternate links or sections connected respectively to permanent
sections of the top, and to extending sections, the permanent sections being mounted
on uprights projecting from the top angles of the tongs, while the extending
sections are mounted on uprights extending or impelled from the bottom angles so
that when the tongs is extended the permanent sections of the table top separate
without rising or falling, while the extending sections rise up between them,
forming a level extended top, and when the tongs is contracted the permanent
sections come together while the extending sections fall beneath them. The lazytongs
are arranged on each side of the table, and the uprights supporting the permanent

page_text: and extending sections are pivoted to said tongs. These uprights are preferably
formed in two parts, an upper and a lower part, jointed midway by a sliding joint
which allows a necessary amount of idle motion, and admits of the contracting and
expanding movements of the tongs sections. The sliding movement of the lower
half of the uprights of the permanent sections is entirely idle as the lower part
imparts no motion to the upper part but simply serves to steady the same in a
vertical position. The sliding movement of the lower part of the uprights of the
movable section is however idle for only a part of the stroke, and when the tongs is
nearly fully extended with the extending sections in position between the permanent,
separated sections, the top of the lower halves of the uprights strike shoulders on
the upper halves, and the upward thrust from the lower angles of the expanding
tongs then raises the sections up between the permanent sections flush with the
surface thereof, thus forming a level extended table top. The upper halves of the
uprights of the movable sections are slotted to admit their independent vertical
motion, and the amount of loose play between the shoulders and the top of the
lower half of the uprights is equal to the full stroke of the lower half, less the
vertical movement of the extending sections, as will be readily understood. The
edges of the permanent and extending sections of the top are bevelled at opposite
angles so as to obtain a wedging action when the two series of sections interinesh,
thus securing a tighter fit and a more certain and easy action of the parts.
When the table is extended it may be thus held by any suitable form of catch,
bolt, or locking device, arranged to lock the lazy tongs and prevent it from moving,
which may be formed in a number of ways, as will be readily understood. It will
also be understood that when the table is to be contracted by unlocking the lazy
tongs and forcing the ends of the table together the contraction of the tongs will at
once cause the extending sections to fall below the permanent sections, which then
close together over them level with fixed end sections which are attached to the
legs, while the extending sections close together beneath.
It will now be seen that by this construction I form a very novel and improved
form of extension table which self contains all its parts and is always complete in
itself, and in which the simple act of pulling apart or extending the ends of the
table automatically presents the extending sections in their true position, and the
simple act of contracting the table ends automatically removes the extending
sections within the body of the table, while owing to the balanced arrangement of
parts this extending or contracting movement is made with great case, thus
preventing many striking advantages over other tables of this class.
In order to prevent any lateral movement of the sections they are braced and
guided against lateral play by a series of longitudinal guide bars intersliding with
each other. Thus a central bar is fixed to the central extending section and this is
guided between pairs of bars fixed on each side and at each end thereof respectively
to the outer sections, and these outer bars slide in troughs or casements fixed to
the leg ends of the table.
In a modification, the uprights of the tongs instead of having a sliding joint
midway, as before, are formed in one piece. The uprights of the permanent
sections are pivoted to the top angles of the tongs as before, but their lower ends
are slotted to slide upon the pivot of the lower angles. The upright of the
extended sections are slotted at each end, the length of the slots being equal to the
vertical stroke of the tongs, less the vertical movement necessary to raise the
sections into place. The construction first described is preferable for its com-
pactness in not extending down the ordinary side boarding of the table, but the
latter construction possesses simplicity and greater rigidity.
It will be seen that the mechanism of the table forms a new mechanical move-
ment which is of course applicable to other articles than tables, for instance, to
extensible screens or blinds, or extensible platforms, and even may be adapted to
gang planks or draw bridges, if desired.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 24th
May 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN EXTENDING TABLES, APPLICABLE ALSO TO
PLATFORMS, GANGWAYS, OR DRAWBRIDGES, BLINDS, AND SCREENS."
A com-
munication from abroad by John Degroat Brassington, of the City, County, and
State of New York, United States, of America.
This Invention aims mainly to provide an extension table in which the extending
sections of the top shall be contained within the table and automatically presented
in proper place when the table is pulled out or extended, thus obviating the
objection of keeping the sections separate from the table and inserting them by
hand, and thereby forming an extension table which is complete in itself. To this
end the Invention may be briefly stated to consist in a table or its equivalent
constructed with a lazytongs connecting its leg ends, and arranged with its width
vertical, with its upper terminals pivoted, and its lower terminals capable of sliding,
and having its alternate links or sections connected respectively to permanent
sections of the top and to the extending sections, the permanent sections being
mounted on uprights projecting from the top angles of the tongs while the extending
sections are mounted on uprights extending or impelled from the bottom angles, so
that when the tongs is extended the permanent sections of the table top separate
without rising or falling while the extending sections rise up between them, forming
a level extended top, and when the tongs is contracted the permanent sections come
together while the extending sections fall beneath them.
In the annexed Drawings Figure 1 represents a side elevation of the improved
table, shown on the point of full extension, and Figure 2 a cross section on line x, x,
Figure 1; Figure 3 illustrates a modification.
In practice the table will be double the length shown in the Drawing, which
shows but half a table of the usual size, one of the pair of end legs forming the
middle legs in a table of full size, as will be readily understood. a, a, indicate the
leg ends of the table to which the fixed end sections 6, 61, of the table top are
directly secured. The leg ends are connected by the lazytongs B, B, arranged as
shown on each side of the table with its width vertical, and having its upper
terminals pivoted to the leg ends, as shown at c, c', and its lower terminals capable
of sliding in slots at d, d¹. e, e, indicate the permanent sections of the table top
and the extending sections which alternate with each other and are attached
to the alternate sections or links of the tongs, as illustrated. The permanent
sections e, as shown, are mounted on uprights g, g, extending from and pivoted to
the upper angles of the tongs, and hence it will be observed that when the tongs is
expanded or contracted the permanent sections will move apart or together in the
same horizontal plane level with the end sections b, 61, without rising or falling.
The extending sections of however are mounted on uprights h, h, extending from and
pivoted to the lower angles of the tongs and capable of a limited play thereon, as
illustrated, so that when the tongs is extended the sections tend to rise by the
upward thrust from the lower angles of the tongs. The uprights g and h are
preferably formed in two parts, an upper and a lower part, jointed midway by a
sliding joint which allows a necessary amount of idle motion and admits of the
contracting and expanding movements of the tongs sections. The sliding movement
of the lower half of the uprights g is entirely idle, as the lower part imparts no
motion to the upper part but simply serves to steady the same in a vertical
position. The sliding movement of the lower part of the uprights h is however
idle for only a part of the stroke, and when the tongs is nearly fully extended with
the extending sections f, f, in position between the permanent separated sections, as

page_text: illustrated in Figure 1, the top of the lower halves of the uprights strike shoulders i, i,
on the upper halves, and the upward thrust from the lower angles of the expanding
tongs then raises the sections ff, up between the sections e, flush with the surface
thereof, thus forming a level extended table top. The upper halves of the
uprights are slotted, as shown, to admit of their independent vertical motion, and
the amount of loose play between the shoulders i and the top of the lower half of
the uprights is equal to the full stroke of the lower half, less the vertical movement
of the extending sections f. f, as will be readily understood. It will be also-
observed that the edges of the permanent and extending sections of the top are
bevelled at opposite angles so as to obtain a wedging action when the two series of
sections intermesh, thus obtaining a tighter fit and a more certain and easy action
of the parts.
When the table is extended it may be thus held by any suitable form of catch,
bolt, or locking devise, arranged to lock the lazy-tongs and prevent it from moving,
which is not shown but may be formed in a number of ways, as will be readily
understood. It will be also understood that when the table is to be contracted, by
unlocking the lazy-tongs and forcing the ends of the table together, the contraction
of the tongs will at once cause the extending sections f to fall below the permanent
sections e, which then close together over them level with the fixed ends b, b¹, while
the extending sections f close together beneath the sectious e, as will be observed
from Figure 1. It will now be seen that by this construction a very novel and
improved form of extension table is produced which self contains all its parts and is
always complete in itself, and in which the simple act of pulling apart or extending
the ends of the table automatically presents the extending sections in their true
position, and the simple act of contracting the table ends automatically removes the
extending sections within the body of the table, while owing to the balanced
arrangement of parts this extending or contracting movement is made with great
ease, thus presenting many striking advantages over other tables of this class.
order to prevent any lateral movement of the sections e, f, they are braced and
guided against lateral play by a series of longitudinal guide bars intersliding with
each other, as shown in Figures 1 and 2. Thus a central bar is fixed to the
central extending section f and this is guided between pairs of bars l, l, m, m, fixed
on each side and at each end thereof respectively to the outer sections f, f, as seen
best in Figure 1, and these outer bars land m slide in troughs or cases n, n, fixed
to the leg ends of the table, as shown.
In
In the modification shown in Figure the uprights of the tongs, instead of
having a sliding joint midway, as in Figure 1, are formed in one piece. The
uprights of the permanent sections e are pivoted to the top angles of the tongs, as
in Figure 1, but their lower ends are slotted to slide upon the pivot of the lower
angles, as illustrated. The uprights of the extending sections fare slotted at each
end, the length of the slots being equal to the vertical stroke of the tongs, less the
vertical movement necessary to raise the sections into place. The construction
shown in Figure 1 is preferable for its compactness in not extending down beyond
the ordinary side framing of the table, but the construction shown in Figure 3 is
preferable for simplicity and greater rigidity, and either construction may be used
when desired.
It will be seen that the main mechanism of the table forms a new mechanical
movement which is of course applicable to other articles than tables, for instance, to
extensible screens or blinds, or extensible platforms, and may even be adapted to
gang planks or draw bridges, if desired.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,-
1st. An extension table or its equivalent constructed with a lazy tongs arranged
with its width vertical, and connecting the leg ends of the table with the permanent
and extending sections e, f, of the table top, supported alternately from the top and
bottom angles of the tongs sections, whereby the action of extending the tongs

page_text: and separating the leg ends of the table causes the permanent sections to separate
on a level line, while the extending sections rise up between them flush with their
surface, substantially as herein set forth.
2nd. The combination of the leg ends a, a, the lazytongs B, B, connecting the
same, the uprights g, h, crossing the sections and angles of the tongs and secured
thereto, and the permanent top sections e and extending top sections f, f, alternating
with each other and mounted on the said uprights, substantially as herein shown
and described.
of
3rd. The combination with the permanent sections e and extending sections
the lazy tongs B arranged in parallel line with said sections, together with the
uprights g, h, crossing and connecting with the sections of said tongs, and supporting
the sections e, f, of the top, and formed in two parts jointed midway by a sliding
joint, substantially as herein shown and described.
4th. The combination in a table, platform, or equivalent of the leg or supporting
ends a, a, the lazytongs B, connecting the same and arranged as shown, the
permanent level sections of the top or platform, and the rising and falling
extending sections f, f, arranged and operating substantially as herein shown and
described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty fourth day of May, in the year of our Lord
One thousand eight hundred and eighty.
A. M. CLARK. (L.S.)