IMPROVEMENTS IN BOLT INDICATORS
Year: 1877

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company, Patent
Solicitors, at Frankfort-on-the-Main, in the Empire of Germany, for the Inven-
tion of "IMPROVEMENTS IN BOLT INDICATORS." A communication from George
Crespel, a person resident in the City of Frankfort-on-the-Main, in the Empire
of Germany.
Sealed the 29th April 1878, and dated the 30th October 1877.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 30th October 1877.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort-on-the-Main, in the Empire of Germany.
"IMPROVEMENTS IN BOLT
INDICATORS." A communication from George Crespel, a person resident in the City
of Frankfort-on-the-Main, in the Empire of Germany.
This Invention relates to an indicator for representing from the outside, or other-
wise, the position of the bolts or catches of locks, especially room-door locks, and
consists in providing the lock bolt with a gradually deepening angle notch. In the
notch there works one end of an angle lever arm, mounted on an axle, which axle
carries an indicator or pointer, arranged to indicate on the outside of the door. The
axle is provided with a spiral spring, so arranged as to keep the angle lever arm.
down, and indicate open or unlocked; but as the bolt is shot the angle lever arm
slides up the angle notch, and the pointer indicates shut or locked. The construction
of indicator and bolt is such that the lock cannot be moved or tampered with by
moving the pointer from the outside.
This Invention is applicable to any existing description of.lock, and especially for
room doors, such as bedrooms, waterclosets, and like doors, where it is advisable to
indicate on the outside that the room is occupied, and thus avoid disturbing the
occupant.
In the case of waterclosets and other doors arranged in multiple, it serves to
indicate which are occupied and which are not, and persons can go to the empty
ones direct, without trying the doors all round.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
the said Frank Wirth in the Great Seal Patent Office on the 29th April
1878.
FRANK WIRTH, of the Firm of Wirth and Company; Patent Solicitors, at
Frankfort-on-the-Main, in the Empire of Germany.. "IMPROVEMENTS IN BOLT
INDICATORS." A communication from George Crespel, a person resident at Frankfort-
on-the-Main, in the Empire of Germany.
Upon reference to the annexed Drawings, Figs. 1, 2, 3, 4, it will be seen that
this Invention relates to an indicator for representing from the outside, or other-
wise, the position of the bolts or catches of locks, especially room-door locks, and
consists in providing the lock bolt with a gradually deepening angle notch a, b. In
the notch there works one end of an angle lever arm d, e, mounted on an axle at e,
which axle carries an indicator or pointer f, arranged to indicate on the outside of
the door. The axle is provided with a spiral spring h, so arranged as to keep the
angle lever arm down, as at d, and indicate open or unlocked, see Figure 2; but as
the bolt A is shot, the angle lever arm slides up the angle notch, and the pointer
indicates shut or locked, see Figure 3. This construction of indicator and bolt is
such that the lock cannot be moved or tampered with by moving the pointer f from
the outside.
2
. This Invention is applicable to any existing description of lock, and especially for
room doors, such as bedrooms, waterclosets, and like doors, where it is advisable to
indicate on the outside that the room is occupied, and thus avoid. disturbing the
occupant.
In the case of waterclosets and other doors arranged in multiple, it serves to
indicate which are occupied and which are not, and persons can go to the empty
ones direct, without-trying the doors all round.
Having now described this Invention, as communicated to me by the said
George Crespel, what is claimed is a mechanism acting, as shown, in such a manner
'as to indicate on the outside of a door that the same is fastened, at the same time
preventing any person outside from opening the door, as herein-before described.
In witness whereof; I, the said Frank Wirth, have hereunto set my hand
and seal, this Twenty-fourth day of April, in the year of our Lord One
thousand eight hundred and seventy-eight.
FRANK WIDBIT