Improvements in School-desks.
Year: 1891

page_text: Date of Application, 21st Feb., 1891
Complete Specification Left, 21st Nov., 1891-Accepted, 23rd Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in School-desks.
I HEBDEN COLBURN of Oakworth near Keighley in the County of York,
Foreman do hereby declare the nature of this invention to be as follows, that is to
say:-
It consists of improvements in school-desks by the employment of which the top-
parts of these desks may be moved or adjusted and held either in a horizontal
position or at any desired angle to this said horizontal position or plane and that in
a more rigid and firm manner than they have been heretofore.
I attain this object by hinging said top part by one of its edges to the standards
or supporting framework, and to the other edge I hinge in an appropriate manner
suitable pendent racks which may be one two or more in number.
These pendent racks are respectively geared with toothed pinions mounted upon
a rotary shaft extending the length of the desk so that when this shaft is rotated
by a handle lever and worn and wheel mechanism (which mechanism maintains any
position in which it may be placed, by reason of all forces acting thereon being
centred in and withstood by the worm) the pendent racks are caused to rise or fall,
as the case may be, carrying with them the top part of the desk.
Instead of these pendent racks being employed screws may be arranged to be
operated vertically by bevel gears mounted thercon and on the horizontal shaft
above described.
Dated this 20th day of February 1891.
HEBDEN COLBURN.
Per Samuel Hey,
Agent.
COMPLETE SPECIFICATION.
Improvements in School-desks.
I HEBDEN COLBURN of Oakworth near Keighley in the County of York,
Foreman 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, that is to say :-
It consists of improvements in school-desks by the employment of which the
top-parts of these desks may be moved or adjusted and held either in a horizontal
position or at any desired angle to this said horizontal position or plane and
that in a more rigid and firm manner than they have been heretofore.
In the accompanying sheets of drawings
Figs. 1 and 2 are sectional front and top views of a school-desk made in
accordance with my invention. The top part of the desk in Fig. 2 is shewn in
broken lines.
Fig. 3 is sectional end view of parts shewn by Figs. 1 and 2.
Figs. 4, 5 and 6 are drawings in detail of parts hereinafter referred to.
Fig. 7 is a drawing in detail of a modified arrangement of mechanism hereinafter
described.
I attain the object of my invention by hinging the top-part a by one of its
edges as a', to the standards or supporting framework band to the other edge a² I
hinge in an appropriate manner, as by the slotted pieces c c¹ the pendant racks d d¹
which may be one (if placed centrally or midway between the extremities of the
part a) two (as shewn) or more (if they are properly disposed) in number.
These racks d d' are respectively geared with the toothed wheels or pinions e e¹

page_text: which are mounted upon the rotary shaft
that extends the whole length of the
desk, by which means when the shaft f is rotated by the wheel g and worm the
said racks d d' are caused to rise or fall, as the case may be or in accordance with
the direction in which said shaft f is rotated, and in their said movements up or down
carry the top-part a with them."
The worm is mounted upon the shaft having a square part ¹ formed on its
outer end for being laid-hold-of by a key or handle lever by the manipulation of
which the shaft k is rotated.
By the employment of the wheel g and worm h in combination with rack and
pinion mechanism as described any position assumed by said racks d d¹ may be
maintained, since all forces acting on said racks d d will be centred in or withstood
by the worm so that the top-part a, carried by said racks d d', is firmly held in
any of its positions.
Instead of the racks d d being employed vertical screws I may be arranged to
act in connection with the top-part a, in which case the bevel wheels m (having a
screw thread to gear with said screw 1) and m¹ (mounted upon the shaft) will be
required in place of the pinion e, while the bevel wheels n n are substituted for
the wheel and worm h, the operations in this arrangement being the same as
those in the former, the weight of the top-part a now being borne by the
screw 1.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. The combination of racks and pinions operated by worm and wheel mechanism,
with school-desks having moveable top-parts substantially as specified, each and all
of said parts being arranged and constructed as set forth."
2. The combination of screws and bevel wheels with school-desks having move-
able top-parts to operate as specified, the same being constructed and arranged
substantially as herein described.
Dated this 20th day of November 1891.
HEBDEN COLBURN.
Per Samuel Hey,
Agent.