IMPROVEMENTS IN SAFETY LAMPS AND APPARATUS EMPLOYED IN CONNECTION THEREWITH
Year: 1869

page_text: LETTERS PATENT to William Young Craig, of Harecastle Collieries,
Stoke-upon-Trent, in the County of Stafford, and Samuel Parker
Bidder, the younger, of Hillfield House, Mitcham, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN SAFETY LAMPS AND
APPARATUS EMPLOYED IN CONNECTION THEREWITH."
Sealed the 25th September 1869, and dated the 2nd April 1869.
PROVISIONAL SPECIFICATION left by the said William Young Craig
and Samuel Parker Bidder at the Office of the Commissioners of
Patents, with their Petition, on the 2nd April 1869.
We, WILLIAM YOUNG CRAIG, of Harecastle Collieries, Stoke-upon-
Trent, in the County of Stafford, and SAMUEL PARKER BIDDER the
younger, of Hillfield House, Mitcham, in the County of Surrey, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SAFETY LAMPS AND APPARATUS EMPLOYED IN CONNECTION THEREWITH," to be as
ollows
Our Invention has reference, firstly, to an improved means of locking

page_text: with by the miners or persons using them; it consists in securing the
wire gauze or other casing of the lamp by means of a bolt, catch, pawl,
or other similar fastening of iron or steel situated inside the lamp and
held in its place by means of a spring, but which bolt or catch on the
application of a magnet to the outside of the lamp shall by the attractive
power of the magnet be withdrawn so as to allow of the wire gauze or
other casing being removed.
Various arrangements of the bolt, catch, or other fastening may be
employed in carrying this Invention into practice; thus a bolt may be
made to pass vertically through the bottom part of the lamp and be
caused by a spring pressing against the under side thereof to project into
a recess in the rim of the casing when this is screwed on, so that when
the magnet is applied the bolt is drawn down so as to allow of the casing
being unscrewed. Or the bolt may be made to pass through the side of
the bottom part of the lamp into a recess or notch in the side of the rim of
the casing, which may in that case either be arranged to unscrew or to turn
on a hinge; or the fastening may be in the form of a pawl catching into
ratchet teeth formed on the inner surface of the rim of the casing, which
pawl is carried on a spindle having an arm, which by being attracted by
the magnet withdraws the pawl from the ratchet teeth, or various other
similar contrivances may be employed, whereby the application of a
magnet to the outside of the lamp causes a spring, bolt, or other fasten-
ing to be withdrawn inside the lamp. The maguet employed for this
purpose may be either a natural or permanent magnet, or an electro-
magnet brought into action at the required moment by a galvanic
battery or other apparatus for producing a galvanic or electric current
or an electro-magnet apparatus may be employed wherein the residuary
magnetism in a bar of soft iron is increased to the required intensity by
the reaction of electric currents induced in the armature and magnet
coils by the forcible rotation of the armature, such as described in the
Specification to C. W. Siemen's Patent, No. 261, of 1867.
The magnets may be conveniently contained in a stand or table so
arranged that the lamp to be opened when placed thereon shall be in
correct position for the poles of the magnet to act upon the bolt or other
fastening as above described, and when horse-shoe magnets are employed
it is preferred to bring the two poles thereof close together so as to act
powerfully upon the bolt or other fastening, or on a piece of iron or stee
attached thereto.

page_text: Another part of our Invention consists in constructing the outer
casing of the Stephenson or "Geordie" safety lamp (in which the flame
is enclosed, firstly, by a glass casing and then by an outer gauze casing,
as now well known and in general use) with the upper part formed of
wire gauze, and with the lower part formed of glass, instead of forming
the whole of wire gauze as heretofore, whereby the illuminating power
of this lamp will be greatly increased. For this purpose the glass
portion of the casing is secured between the lower rim of the casing and
an intermediate ring connected to the lower rini by means of metal bars,
to which intermediate ring the lower end of the gauze casing is secured,
while the upper end thereof is held as usual by an upper ring connected
by other metal bars to the intermediate ring similar to the arrangement
known as the "Clanny" lamp.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Young Craig and Samuel Parker Bidder
in the Great Seal Patent Office on the 30th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
YOUNG CRAIG, of Harecastle Collieries, Stoke-upon-Trent, in the County
of Stafford, and SAMUEL PARKER BIDDER, the younger, of Hillfield
House, Mitcham, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of April, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said William Young Craig and Samuel
Parker Bidder the younger, Her special licence that we, the said William
Young Craig and Samuel Parker Bidder the younger, our executors,
administrators, and assigns, or such others as we, the said William Young
Craig and Samuel Parker Bidder the younger, our executors, adminis-
trators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN SAFETY
LAMPS AND APPARATUS EMPLOYED IN CONNECTION THERE WITH," upon
the con-

page_text: dition (amongst others) that we, the said William Young Craig and
Samuel Parker Bidder, the younger, our executors or administrators,
by an instrument in writing under our or their hands and seals, or
under the hand and seal of one of us or them, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and im-
mediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Samuel Parker Bidder the
younger,
on behalf of myself and the said William Young Craig, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accompany-
ing Sheet of Drawings and to the figures and letters marked thereon, that
is to say:
Our Invention has reference to an improved means of locking safety
lamps whereby they are effectually protected from being tampered with
by the miners or persons using them; it consists in securing the wire
gauze or other casing of the lamp by means of a bolt, catch, pawl, or
other similar fastening of iron or steel situated inside the lamp and
held in its place by means of a spring, but which bolt or catch on the
application of a magnet to the outside of the lamp shall, by the
attractive power of the magnet be withdrawn so as to allow of the wire
gauze or other casing being removed.
Varicus arrangements of the bolt, catch, or other fastening may be
employed in carrying this Invention into practice; thus a bolt may be
made to pass vertically through the bottom part of the lamp and be
caused by a spring pressing against the under side thereof to project
into a recess in the rim of the casing when this is screwed on, so that
when the magnet is applied the bolt is drawn down so as to allow of
the casing being unscrewed. Or the bolt may be made to pass through
the side of the bottom part of the lamp into a recess or notch in the side
of the rim of the casing which may in that case either be arranged to
unscrew or to turn on a hinge; or the fastening may be in the form of
a pawl catching into ratchet teeth formed on the inner surface of the
rim of the casing, which pawl is carried on a spindle having an arm
which by being attracted by the magnet withdraws the pawl from the
ratchet teeth, or various other similar contrivances may be employed

page_text: whereby the application of a magnet to the outside of the lamp causes
a spring, bolt, or other fastening to be withdrawn inside the lamp. The
magnet employed for this purpose may be either a natural or permanent
magnet, or an electro-magnet brought into action at the required
moment by a galvanic battery or other apparatus for producing a
galvanic or electric current, or an electro-magnet apparatus may be
employed wherein the residuary magnetism in a bar of soft iron is
increased to the required intensity by the reaction of electric currents
induced in the armature and magnet coils by the forcible rotation of
the armature, such as described in the Specification to C. W. Siemens'
Patent, No 261, of 1867.
The magnets may be conveniently contained in a stand or table so
arranged that the lamp to be opened when placed thereon shall be in
correct position for the poles of the magnet to act upon the bolt or
other fastening as above described, and when horse-shoe magnets are
employed it is preferred to bring the two poles thereof close together so
as to act powerfully upon the bolt or other fastening, or on a piece of
iron or steel attached thereto.
Having thus set forth the nature of our Invention we will now
proceed more particularly to describe those arrangements for carrying
the same into practice which we prefer to employ, for which purpose we
shall refer to the accompanying Sheet of Drawings.
Figure 1 shews a sectional elevation, and Figure 2 shows a sectional
plan of a safety lamp with our improved system of locking the same
applied thereto.
For this purpose the oil chamber A of the lamp has a double bottom B
beneath which is formed a second chamber C, in this chamber is a piece
of iron or steel or armature D secured at one end loosely to the bottom E
by means of a screw F, while at the other end it carries (also loosely)
a pin or bolt G passing up through a hole formed in the body of the
oil chamber A and into a recess or notch H in the rim of the upper
part or casing I, thereby locking such casing on to the lamp. The
armature D is held in this position by means of the steel spring K
secured to the bottom E and made to press the armature upwards. In
order to unlock the lamp for lighting the same the bottom thereof is
placed in contact with the poles L, L, of the electro or other magnet M,
Figure 3, whereby the armature D in being attracted by such poles with
greater force than that exercised by the spring, moves downwards

page_text: towards them, and thereby withdraws the bolt G from the notch H,
thus allowing the casing I to be unscrewed. On screwing on the casing
again after lighting the lamp and removing this from the poles of the
magnet M (or simply breaking the current if an electro-magnet is
employed) the spring will again press the armature upwards, thus
causing the bolt G to enter the notch H again so as to lock the lamp.
The lamp A being made of brass it is preferred in order to increase the
action of the magnet upon the armature to let into the bottom E two
pieces of iron or steel e, e, at those points where the poles of the magnet
come in contact therewith, and in cases where the magnet is required to
act upon lamps having different arrangements of the armature, such as
hereafter described, the poles L, L, are preferably made adjustable as
indicated in dotted lines. The spring K being made sufficiently strong
to prevent the withdrawing of the bolt by any mere jerking down of
the lamp, it will be seen that the unlocking of such lamps by any other
person than the man who has charge of the magnet is rendered
impossible.
Figures 4 and 5 shew respectively a part sectional elevation, and a
sectional plan of a slightly modified arrangement wherein the plate or
armature D is not connected to the bottom E, and is maintained in the
position shewn so as to effect the locking of the lamp by means of the
spiral spring K. The armature is made of sufficient length (as shewn
in Figure 5) to be acted upon by both poles of the electro or other
magnet. It will be evident that in place of holding the armature in
the locked position by means of a spring this might be effected by
means of a small permanent magnet fixed inside the lamp arranged so
as to attract the armature in the opposite direction to that in which it
is acted upon by the external magnet. Also in place of effecting the
motion of the bolt itself by the magnet it may be withdrawn by means
of a key or by the hand and secured in locking position by means of a
secondary bolt or catch acted upon by the magnet.
Having thus described the nature of our Invention, and in what
manner the same is to be performed, we wish it to be understood that
we in no way limit ourselves to the particular arrangements of the
same herein-before described, as it is evident that these may be greatly
varied without departing from the essential features of our Invention,
but what we claim is,-
First. Securing or locking safety lamps by means of a bolt, catch

page_text: S. P. BIDDER, JUN, (L.B.)