IMPROVEMENTS IN CONVERTIBLE SCHOOL DESKS
Year: 1879

page_text: LETTERS PATENT to Alfred Wilks, of Oldbury, in the County of Worcester,
Ironfounder, for the Invention of "IMPROVEMENTS IN CONVERTIBLE SCHOOL
DESKS."
Sealed the 2nd March 1880, and dated the 6th September 1879.
PROVISIONAL SPECIFICATION left by the said Alfred Wilks at the Office
of the Commissioners of Patents on the 6th September 1879.
ALFRED WILKS, of Oldbury, in the County of Worcester, Ironfounder.
PROVEMENTS IN CONVERTIBLE SCHOOL DESKS."
"
IM-
My improvements consist in constructing and arranging, in the manner herein
after described, the parts of the said desks so that the slab of the desk can be
readily brought into and fixed in the 'inclined position suitable for writing upon, or
into a horizontal position so as to convert the desk into a table, or into a vertical
position on either side of the supporting standards so as to form the back to a seat
on either side of the said standards.
I construct and arrange the parts in the following manner :- -To the top of each.
of the two standards, by which the slab of the desk is supported at each end, I fix
a semi-circular metallic guide, and to the underside and near each end of the slab
I fix a bracket. The lower parts of these brackets are divided, the divided or
forked parts embracing the semi-circular guides. The bottoms of the forked
brackets are jointed to the centres of the metallic guides respectively. The upper
side of each semi-circular guide has two notches, one immediately over the central
joint described, and the other making a small angle therewith.
In the upper part of each bracket is a nearly rectangular recess in which a bolt
of corresponding figure slides in the direction of a radius to the joint. The under-
side of this sliding bolt carries a tooth of a size and shape proper to engage in the
notches in the semi-circular guide. When this tooth is engaged in the notch situated
over the joint the slab is fixed in a horizontal plane and constitutes a table. When
the said tooth is engaged in the other notch the slab is fixed in an inclined position
and constitutes a desk. When the tooth is not engaged in either of the notches the
slab may be turned into a vertical position on either side of the standards,, and
then constitutes a back to a seat on one or other side of the standards.
The engaging of the teeth with the notches and their removal therefrom are
effected as follows:-The sliding bolts carrying the teeth have square holes in them.

page_text: A rod or axis running underneath the slab, and having its bearings in the brackets,
is furnished with cams on those parts which are situated in the holes in the sliding
bolts. By means of a key or handle applied to one end of the axis the said axis
may be turned. When the said axis is so turned that its cams are in their highest
position the bolts are lifted and their teeth disengaged from the notches. The slab
can now be moved upon the joints described and brought into an inclined position.
By now giving a semi rotation to the axis the cams are brought into their lowest
position, and the teeth are depressed into and pressed lightly down in one or other
of the notches in the semi circular guides. When the slab is brought into a vertical
position it is supported in that position by the tops of the standards.
In order to give great steadiness to the slab in its table and desk positions, the
sliding bolt and the recess in which it works taper slightly downwards, so that
when the said bolt is in its depressed or locking position it has no play in its
recess, and consequently fixes the slab very rigidly.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Wilks in the Great Seal Patent Office on the 2nd March, 1880.
ALFRED WILKS, of Oldbury, in the County of Worcester, Ironfounder."
PROVEMENTS IN CONVERTIBLE SCHOOL DESKS."
"IM-
My improvements consist in constructing and arranging, in the manner herein
after described, the parts of the said desks so that the slab of the desk can be
readily brought into and fixed in the inclined position suitable for writing upon or
into a horizontal position so as to convert the desk into a table, or into a nearly
vertical position on either side of the supporting standards so as to form the back.
to a seat on either side of the said standards.
I construct and arrange the parts in the following manner:-To the top of each
of the two standards, by which the slab of the desk is supported at each end, I fix
a-semi-circular metallic guide, and to the underside and near each end of the slab
I fix a bracket. The lower parts of these brackets are divided, the divided or forked
parts'embracing the semi-circular guides. The bottoms of the forked brackets are
jointed to the centres of the metallic guides respectively. The upper side of each
semi-circular guide has two notches, one immediately over the central joint
described, and the other making a small angle therewith.
In the upper part of each bracket is a nearly rectangular recess, in which a bolt of
corresponding figure slides in the direction of a radius to the joint. The underside
of this sliding bolt carries a tooth of a size and shape proper to engage in the notches in
the semi-circular guide. When this tooth is engaged in the notch situated over the
joint the slab is fixed in a horizontal plane and constitutes a table. When the said
tooth is engaged in the other notch the slab is fixed in an inclined position and
constitutes a desk. When the tooth is not engaged in either of the notches the
slab may be turned into a nearly vertical position on either side of the standards,.

page_text: and then constitutes a back to a seat on one or other side of the standards. The
engaging of the teeth with the notches and their removal therefrom are effected as
follows: The sliding bolts carrying the teeth have square holes in them. A rod or
axis running underneath the slab and having its bearings in the brackets is
furnished with cams on those parts which are situated in the holes in the sliding
bolts. By means of a key or handle applied to one end of the axis the said axis
may be turned. When the said axis is so turned that its cams are in their highest
position the bolts are lifted and their teeth disengaged from the notches. The
slab can now be moved upon the joints described and brought into an inclined
position. By now giving a semi-rotation to the axis the cams are brought into.
their lowest position, and the teeth are depressed into and pressed tightly down in
one or other of the notches in the semi-circular guides. When the slab is brought
into a nearly vertical position it is supported in that position by the tops of the
standards.
In order to give great steadiness to the slab in its table and desk positions, the
sliding bolt and the recess in which it works taper slightly downwards, so that,
when the said bolt is in it depressed or locking position it has no play in its recess,
and consequently fixes the slab very rigidly.
I will now proceed to describe, with reference to the accompanying Drawings, the
manner in which my Invention may be performed.
Figure 1 represents in end elevation, and Figure 2 a'portion of the same in
vertical transverse section, a convertible school desk constructed according to my
Invention, the slab of the desk being fixed or locked in a horizontal position to
convert the desk into a table; Figure 3 represents the slab of the desk fixed or locked
in its inclined position for writing upon; and Figure 4 represents the slab turned
into a nearly vertical position for. forming a back to the seat of the desk; Figure 5
represents an elevation of the inner side of one of the brackets of the desk, and
Figure 6 represents a longitudinal vertical section of the desk taken through the
two brackets of the standards.
The same letters of reference indicate the same parts in the several Figures of the
Drawings.
a, a, are the metal standards of the desk; b is the wooden slab of the desk, and c
is the seat; d, d, are the semi-circular metallic guides fixed to the tops of the
standards a, u. In Figure 6 one of the guides d is shown in edge view, and the
other in vertical section. Each of the said semi-circular guides d is furnished with
two notches marked respectively e and f. To the underside of the slab b of the
desk and near each end a bracket h is fixed, the said brackets being jointed at h², h*,
to the centres of the fixed metallic guides d, d. By jointing the brackets to the
fixed guides in the manner represented the said brackets and the slab b carried by
them may be turned through about a semi-circle on the fixed guides. The jointed
brackets h, h, are forked at their lower parts, the forked parts embracing the thick
semi-circular guides d, d, (see the longitudinal section, Figure 6). In the upper part
of each jointed bracket h is a rectangular recess i in which a bolt k of a corre-
sponding figure slides in the direction of a radius to the joint h². These bolts are
introduced into the recesses i, i, in the jointed brackets h, h, before the slab b is
fixed to the said brackets.
'
On the underside of each sliding bolt k is a tooth 7 of a size and shape proper to
engage in one or other of the notches e, f, in the semi-circular guide d. By and
examination of Figures 1, 2, 3, and 4, it will be seen that the notch e in each guide &
is situated immediately over the joint on which the bracket h turns, and that the
other notch fmakes a small angle with the notch e.
When the teeth 1, 7, of the sliding bolts k, k, are engaged with the central notches
e, e, in the guides h, h, the slab b is fixed or locked in a horizontal plane and
constitutes a table, as seen in Figures 1 and 2. By lifting the bolts k, k, in the
manner herein after explained, and engaging their teeth with the other notches f, f,
in the guides h, h, the slab b is fixed or locked in the inclined position represented
in Figure 3, and constitutes a desk. By lifting the teeth 1, 1, of the bolts k, k, out of

page_text: one or other of the pairs of notches, and moving the slab b to the right hand or left
hand it may be turned into a nearly vertical position on either side the standards
a, a, and in this position the slab constitutes a back to the seat c, as illustrated in
Figure 4. The jointed brackets h, h, when turned down, as last described, are
supported by the stops or shoulders m, m, at the base of the fixed guides d, d, on
the standards a, a. The sliding bolts k, k, are worked for engaging their teeth
with, and disengaging them from the notches e, e, or f, f, in the fixed guides d, d,
by means of the rod or axis n having square ends. The ends of this rod or axis n
pass through and turn in bearings in the brackets h, h, the said axis also passing
through rectangular holes in the bolts k, k. The part near each end of the rod or
axis n situated in the hole in the bolt k is furnished with a cam p. The shape of
the cams P, P, is best seen in the transverse sections, Figures 2, 3, and 4. By
turning the axis n by means of a key or handle applied to one of its square ends
the cams p, p, on the said axis may be made either to bear on the lower or upper
inner faces of the boxes of the bolts k, k. When the cams p, p, are in their lowest
position, and bear on the lower faces of the boxes of the bolts k, k, the teeth of the
said bolts are pressed downwards and made to engage with the notches over
which they are brought in the fixed guides d, d, as seen in Figures 2 and 3, and
when the said axis is turned through a semi-circle so that its cams are in their
highest position, they bear on the upper faces of the boxes of the bolts and lift the
said bolts out of the notches in the guides d, d, and release the brackets h, h, as
seen in Figure 4, and the slab b carried by the jointed brackets h, h, may be turned
into the desired position, that is, either into the table position, Figures 1 and 2, or
into the desk position, Figure 3, or into the back position, Figure 4, as before
explained. The cams p, p, are introduced into the boxes in the sliding bolts k, k,
by means of a slot in the inner side of each bracket h before the said brackets are
fixed in their places. These slots are shown in the sections Figures, 2, 3, and 4, and
elevation Figure 5, and are marked q. After the cams have been passed through the
slots q, q, in the brackets the axis n is turned so as to remove the said cams from.
opposite the slots, and the brackets are then jointed to the fixed guides d, d. The
cams p, p, on the axis n are thereby prevented from moving longitudinally in the
boxes of the bolts in which they work.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I claim as my Invention,-
The improvements in convertible school desks herein before described and illustrated
in the accompanying Drawings, that is to say, the combination of the notched semi-
circular guides d, d, fixed to the standards of the desk, with the forked brackets h, h,
fixed to the slab of the desk, the said forked brackets being jointed to the centres
of the said fixed guides, the said jointed forked brackets and fixed guides being
used in conjunction with the sliding locking toothed bolts k, l, k, l, for engaging with
the notches in the fixed guides, and with the cams and axis n, p, p, for raising the
said bolts from, and dépressing and locking them in the said notches of the fixed
guides; the several parts being constructed, and arranged, and working substantially
as and for the purposes described and illustrated.
In witness whereof, I, the said Alfred Wilks, have hereunto set my hand
and seal, this Twenty third day of February, in the year of our Lord One
thousand eight hundred and eighty.