Improvements in or relating to Door Knobs.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Door Knobs.
We, JAMES CARPENTER TILDESLEY and CLEMENT TILDESLEY, trading
together in co-partnership as Carpenter and Tildesley, of Summerford Works,
Willenball in the County of Stafford, Lock Manufacturers, 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:-
This invention has for its object to supply a want long felt for a door knob
suitable in all respects for transport to distant countries and use in hot climates,
namely, as regards cheapness in cost of manufacture, lightness and consequent
saving in cost of carriage, facility of adjustment along a spindle to suit varying
thicknesses of doors, resistance to surface corrosion or discolouration liable to be
produced by moisture of the hand, strength and durability.
Brass knobs, owing to their being made mainly of sheet metal which is spun
on to a cast neck, are very light. They are also cheap in first cost and are very
strong and durable; and they can be readily adjusted along a spindle to suit
varying thicknesses of doors, as their outer ends being of sheet metal the
end of the spindle may come almost to the outside of the larger end of the
knob. But in some countries having a hot climate the use of these knobs has
been abandoned, in consequence of their liability to become tarnished by the
contact therewith of a moist hand.
Electro-plated knobs are too expensive for ordinary use, such as with the cheaper
kinds of locks usually sent to South American and colonial markets.
China and earthenware knobs are almost solid and are consequently heavy and
expensive in carriage; and, moreover, the spindle holes in them cannot be brought
very near to the outer or larger ends, as it is necessary to leave a considerable
thickness of material across the outer ends of the holes, and thus the degree of
their adjustment on their spindles is, on this account alone, more limited than in
the case of metal knobs. It is usual also, in the case of a pair of china or
earthenware knobs, to lead one of such knobs on the spindle and to make one
only adjustable thereon, on account of the weakening of the neck occasioned by
forming a pin hole therethrough necessary when the knob is made adjustable and
the advisability of not weakening both the knobs in this manner; thus lessening
very greatly the adjustability of a pair of knobs in relation to one another.
These knobs are very liable also to get chipped or cracked.
Brass knobs therefore are, but for their liability to tarnish, the most suitable for
use with the cheaper kinds of locks required in distant countries having hot
climates; and the problem as to how such knobs might be rendered capable of
being used without injury to their surfaces by contact therewith of a moist hand,
has heretofore remained unsolved.
Now, this problem is solved, and the object of this invention effected, by
coating brass knobs with an unoxidizable enamel or enamel varnish which may be
laid on by dipping the knobs therein or by means of a brush, and which may be
set hard in a stove. Such knobs have all the advantages of brass knobs, without
the disadvantage on account of which their use has been abandoned in hot climates.
The coating material we prefer to employ, and which we find answers the purpose
admirably, is known in trade as "cycle-enamel," being used largely by cycle
manufacturers for enamelling frames and other parts of cycles.
The nobs may
be conveniently coated by dipping them within the enamel (for which purpose
what is known as "dipping enamel" is used) being suspended for such purpose by
a piece of wire. They should then be hung over the dipping vat for about ten
minutes to allow the surplus enamel to drop off, and then any hangers or runners
D

page_text: should be removed with a camel's hair brush. The knobs should then be hung for
about an hour in a stove (conveniently a wrought iron gas stove) heated to about
350 degrees Fahrenheit. The two parts of a knob being fixed together by
spinning without the use of solder or brazing, the knobs may be safely submitted
to the stove heat necessary to set the enamel. The dipping enamel is usually
more liquid than that which is used when it is to be laid on to the article to be
enamelled by means of a brush, the distinction between dipping enamel and enamel
to be laid on by a brush being one well known to manufacturers of enamels and
varnishes. The knobs may, of course, be coated with enamel laid on by a brush,
if preferred, instead of being dipped into the dipping enamel.
1
It is preferred to coat the knobs with two coats of enamel, the first coat being
put on and stoved before the second coat is applied. For very common work one
coat may sometimes be considered sufficient; and for superior work more than
two coats may be put on, if desired.
The enamel may be obtained in different colours, and thus a variety of choice
may be afforded to the consumer; and, moreover, the knobs may be ornamented
by the application thereto of designs in different coloured enamels.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :--
1. Brass door knobs coated with unoxidizable enamel or enamel varnish, sub-
stantially as described for the purpose set forth.
2. Brass door knobs coated with cycle enamel by first covering their exterior
surfaces therewith and then setting in a stove, substantially as described, for the
purpose set forth.
Dated this 17th day of August 1899
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicants.