IMPROVEMENTS IN CHAIRS
Year: 1876

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
CHAIRS." A communication from abroad by William Toan Doremus, of the
City, County, and State of New York, United States of America.
Sealed the 26th May 1876, and dated the 7th April 1876.
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark at the
Office of the Commissioners of Patents on the 7th April 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN CHAIRS." A communication from abroad by
William Toan Dorenus, of the City, County, and State of New York, United States
of America.
The object of this Invention is to furnish chairs in which the bases shall be
simple in construction, inexpensive in manufacture, strong and durable, and may
be shipped in a "knock down" shape, and readily put together by the buyer, in
which the connection between the chair seat and base shall be such that the chair
will yield to the movements of the person sitting upon it instead of opposing a
rigid resistance to said movements as an ordinary chair does, and at the same time
may have oscillating or backward and forward movement, and in which the back
frame shall be so constructed as to cover and hide the springs and the devices by
which the seat is connected with the base, and when made without a screw or
pivot shall have the seat and base so connected that when the springs are put
under pressure the reaction may be in the direction of the length of the coupling
bolts.
The Invention consists in the socket provided with a plate or flange cast solid
therewith, and having angular recesses formed upon its under side to receive
the angular upper sides of the legs; in the combination of the bottom flange or
plate, with the socket, the top plate or flange, and the legs, whether the bottom
plate be made solid with or separate from the said said socket and top flange, in the
ribs or braces, placed in the angle between the socket and the top flange or plate
and cast solid therewith; in the plates constructed with flanges, points, and pivot,
said plates being bolted together to hold the legs; in the combination with hooks,
cross bar having inclined seats at its ends and rubber blocks, and of rock bar that
connects the arms; in the combination of cross heads, yokes, bolts, and rubber
blocks with the cross bar and the rock bar; in the combination of the rock bar,
front cross bar, pivot bar, and arms, to bring the centre of oscillation in front of
the centre of rotation; in the inclined back posts, the upright braces, and the
[Price Gd.1

page_text: panels in combination with the seat of a chair; in the downward projection of
the posts, the braces, and the panels below the seat, to cover the connection
between the said seat and the base; and in the combination with the base of the seat
and the springs of the bolts, provided with nuts upon their lower ends, and arranged
at such an inclination that the reaction of said springs, when under pressure, may
be in the direction of the length of said bolts, as herein-after fully described.
In the accompanying Drawings, Figure 1 is a top view of the base of the
improved chair; Figure 2 is a vertical section of the same taken through the line
,, Figure 1; Figure 3 is a side view of the same, the legs being removed;
Figure 4 is a side view of a modified form of the same; a leg is also shown
separately in section through the line y, y, Figure 2; Figure 5 is a side view, partly
in section of a modified form of the same; Figure 6 is a vertical section of another
modified form of the same; Figure 7 is a top view of another modified form of the
same Figure S is a horizontal section of the same, taken through the line 2, 2,
Figure 9, which is a rear view of the spring mechanism of the improved chair,
partly in section, through the base; Figure 10 is a side view of one of the rubber
blocks and its seat and top bar; Figure 11 is a detail section taken through the
line u, u, Figure 9; Figure 12 is a detail section taken through the line v, v,
Figure 9; Figure 13 is a side view of a chair; Figure 14 is a vertical section of
the same; Figure 15 is a detail section taken through the line w, w, Figure 13,
Figure 16 is a side view of a chair showing a modification of the panel; Figure 17
is a detail horizontal section of the same taken through the line 8, s, Figure 16;
Figure 18 is a detail vertical section of the same taken through the line t, t,
Figure 16.
A is a socket for the pivot of the chair, which when a screw chair is to be
made, has a screw thread cut in its inner surface to receive the threads of the
screw, and which is made long enough to give a firm bearing to said pivot or
screw; B is the top plate of the chair base, which is so made as to form four, more
or less, V shaped or angular recesses upon its lower side to receive the V shaped or
angular upper sides of the legs C. The upwardly projecting angular parts of the
plate or flange B may be cut away next the socket A, as shown in Figures 1, 2, 3,
and 4, to make the bases lighter, or said plate or flange may extend to said
socket A, as shown in Figures 5 and 6. The plane of the top of the plate or
flange B may be horizontal, or nearly so, as shown in Figures 1, 2, 3, and 4, or it
may incline downward, as shown in Figures 5 and 6, at any desired angle.
The plate or flange B may be strengthened by ribs or braces b¹ extending to the
socket A and cast solid therewith, as shown in Figures 3, 4, and 5. The inner ends
of the legs C rest against the sides of the socket A, and the outer parts of the
plate or flange B rest upon the upper sides of the said legs C; the lower sides
of the inner ends of the legs C rest upon a plate or flange D which may be angular,
as shown in Figure 3, or flat, as shown in Figures 4 and 6, according as the lower
side of the legs C may be angular or flat. The flange or plate D may be cast solid
with the socket A and flange or plate B, as shown in Figures 2, 3, and 4, or it may
be separate and secured by bolts passing down through the plate or flange B, and
through or between the legs C. The plate or flauge D may be omitted and the
inner ends of the legs C held in place by bolts passing through the plate or flange B
and through the said legs C, as shown in Figure 5. The legs C may be guarded
against dropping out by points or bolts attached to the inner surface of the plates
or flanges B, D, either or both, and passing into or through the said legs C.
In the modification shown in Figures 7 and 8 the inner ends of the legs C are
beveled off so as to meet in a centre, as shown in Figure 8. The inner parts of
the legs C are placed between two plates E, F, which are secured in place by
bolts & passing through the said plates E, F, and through the angular space
between said legs C. The bodies of the bolts G may be concealed by small orna-
mental blocks placed upon them within the angular spaces through which they
pass. If desired the bolts G may pass through the plates E, F, and through the
legs C, but I prefer the construction first described as it avoids boring the said legs.

page_text: The outer edge of the lower plate E is notched to receive the inner edges of the
legs C, and has flanges e formed upon its upper surface to keep the said legs from
lateral movement. For the same reason flanges f1, Figure 9, may be formed upon
the lower surface of the upper plate F. Upon the lower surface of the upper
plate F may also be formed points to enter the tops of the legs C and prevent
them from being drawn out. Upon the centre of the upper plate F is cast the
pivot H which passes up through the centre of the cross bar I, and is secured by a
pin or other convenient means. The cross bar I is supported by a tubular projec-
tion or hub formed upon its lower side through which the pivot H passes, and
the lower end of which rests and turns upon the plate F. Upon the ends of the
cross bar I are formed cross heads J to serve as seats for the rubber blocks K which
form the springs.
The rubber blocks K may be made wedge-shaped or of any other suitable form,
and are kept from slipping out of place by flanges formed along the side edges
and the lower end edge of the cross head J. Upon the top of the rubber block K
rest the cap arms L, the forward parts of which are made about twice as long as
their rear parts.
The end parts of the arms L are bent upward and then out-
ward, and have holes formed through them to receive the screws by which they
are secured to the chair seat. The parts of arms L that rest upon the rubber
blocks K have flanges formed upon their side edges to prevent them from slipping
off the said rubber blocks. The two arms L at about the middle part of the
rubber block K are rigidly attached to or formed solidly upon the ends of a rock
bar M which is thus placed above and a little in front of the cross bar J. The arms L
are held in place upon the rubber blocks K by hooks N formed upon the cross bar I,
and which hook over the rock bar M, as shown in Figures 9 and 11, or cross heads O
may be formed upon the cross bar I, to the end parts of which are bolted the ends
of yokes P which pass over the rock bar M and have recesses formed in them to
receive the said rock bar M.
The forward end of the yokes P have flanges formed upon them which overlap
the ends of the cross heads O to relieve the bolts Q from a side strain when the
chair is oscillated; R are rubber blocks interposed between the ends of the cross
heads and the yokes P, and through which the bolts Q pass to keep them in
their places. The rubber blocks R by their clasticity take up the slack when the
rubber blocks K are under pressure to prevent the yokes P from rattling.
With some styles of chairs the hooks N may be used, and with other styles the
cross heads O and the yokes P will be preferable, or both may be used upon the
same chair, as shown in Figure 9. The rock bar M is placed forward of the cross
bar I, to bring the centre of oscillating motion forward of the centre of rotary
motion, and thus enable a smaller base to be used than would otherwise be
necessary, and prevent the front feet from projecting beyond the front of the chair.
In Figures 13 and 14 S represents the base of the chair to which the seat T is
connected by the bolts U. The upper ends of the bolts U are pivoted to the seat T
in such a way that the said seat may rock forward and backward upon the said
bolts. The bolts U pass down through the base S with a forward inclination, as
shown in Figures 13 and 14, so that when a person sits down in the chair and
depresses the rear part of the seat, the resistance or reaction may be in the direction
of the length of said bolts. V are rubber or other springs interposed between the
seat T and the base S in the rear of the bolts U, which are designed to give elasticity
to the chair, and the clasticity of which may be regulated by adjusting the nuts
upon the lower ends of said bolts U; W are rubber or other springs interposed
between the seat T and the base S in front of the bolts U, to serve as elastic stops
when the pressure is removed from the spring V, or when the seat T is tipped
forward; X are the side posts of the back which are inclined to the rearward.
The lower parts of the posts X are secured to the sides of the seat T in front of
the bolts U, and their lower ends project downward below said seat, and are
widened to partially cover the connection between the scat T and the base S. The
posts X are supported in position by the upright braces Y, the upper ends of which

page_text: are secured to the middle part of the posts X. The lower parts of the braces Y
are secured to the seat T and their lower ends project below the seat T and the
hase S. The angular space between the posts X and the braces Y is closed by
the panels Z, the edges of which are slid into grooves in the inner edges of the
said posts X and braces Y, as shown in Figure 15, and in dotted lines in Figures
13 and 14. The lower ends of the panels Z project downward below the seat T to
cover the connection between the scat T and the base S; the panels Z need not
extend above the seat T and may be attached to the sides of the downwardly project-
ing ends of posts X, and braces Y if desired. This construction allows the panels Z
to be conveniently removed to give access to the sides of the seat T for con-
venience in upholstering the said seat, and to give access to the connections between
the seat T and the base S when required. The panels Z also guard against the
possibility of a person getting his fingers or clothing caught in the operating
mechanism of the chair; to the forward side of the posts X are attached the arms A¹.
The upper ends of the posts X are connected by a curved slot B'.
The back of the chair may be made of canvas or other suitable material; the
posts X, braces Y, panels Z, and arm A¹, may be curved or otherwise ornamented
to any desired extent.
Having described the nature of the Invention and the manner of performing
the same, I declare that what I claim as new and desire to secure by Letters
Patent is,
-
1st. The socket A provided with a plate or flange B cast solid therewith, and
having angular recesses formed upon its under side to receive the angular upper
sides of the legs C, substantially as herein shown and described.
2nd. The combination of the bottom flange or plate D, with the socket A, the
top plate or flange B, and the legs C, whether the said plate D be inade solid with
or separate from the said socket A and flange B, substantially as herein shown and
described.
3rd. The ribs or braces 61 placed in the angle between the socket A and the
flange or plate B and cast solid therewith, substantially as herein shown and
described.
4th. The plates E, F, constructed with flanges c¹, f¹, points ƒ³, and pivot H,
said plates being bolted together to hold the legs C, in the manner set forth.
5th. The combination with hooks N, cross bar I, having inclined seats J at its
ends, and rubber blocks K and of rock bar M that connects arms L, as and for the
purpose specified.
6th. The combination of cross heads O, yokes P, bolts Q, and rubber blocks R,
with the cross bar I and rock bar M, as and for the purpose specified.
7th. The combination of the rock bar M, front cross bar I, pivot bar H, and
arms L, as shown and described to bring the centre of oscillation in front of the
centre of rotation.
8th. The inclined posts X, the upright braces Y, and the panels Z in com-
bination with the seat T of a chair, substantially as herein shown and described.
9th. The downward projection of the posts X, the braces Y, and the panels Z
below the scat T, to cover the connection between the said seat T and the base S,
substantially as herein shown and described.
10th. The combination with the base S, the seat T, and the spring V, of the
bolts U, provided with nuts upon their lower ends arranged at such an inclination
that the reaction of said springs, when under pressure, may be in the direction of
the length of said bolts, substantially as herein shown and described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Sixth day of April, in the year of our Lord One thousand
eight hundred and seventy-six.
A. M. CLARK. (L.S.)