AN IMPROVED KEY-HOLE PROTECTOR.
Year: 1878

page_text: LETTERS PATENT to Friedrich Hermann Felix Engel, Civil Engineer and
Patent Agent, in the City of Hamburg, Germany, for the Invention of
56
AN IMPROVED KEY-HOLE PROTECTOR.' A communication from Wilhelm
Colshorn, of Hamburg, in the German Empire.
Sealed the 27th May 1879, and dated the 28th November 1878.
PROVISIONAL SPECIFICATION left by the said Friedrich Hermann Felix
Engel at the Office of the Commissioners of Patents on the 28th November
1878.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. 'AN IMPROVED KEY-HOLE PROTECTOR." A com-
munication from Wilhelm Colshorn, of Hamburg, in the German Empire.
This Invention relates to improved apparatus to be used as a key-hole protector
and consists of the introduction of a metal plug or lock piece, in shape similar to
the pin and bit of a common key, into the key-hole of locks, and in fastening this
arrangement to the cover plate of the lock by means of a special key. By this
means the key-hole is locked up and the lock rendered unpickable.
For opening the lock the protector must be removed by means of the special
key belonging to same and then the lock can be opened by the corresponding
key.
The body of the protector is similar in shape to the bit of a key, and in said body
a pin, furnished with a projection at its outer end, is placed, this pin having a slit or.
notch for the reception of the special key.
When inserted in the key-hole the protector is in open position and when turned
by means of the key it is closed and the projecting pin is behind the coverplate of
the lock.

page_text: From this closed position the protector can only be removed after the projecting
pin has been turned sufficiently by means of the special key to allow the projection
to pass out through the key-hole.
The special construction of this protector is as follows:-
The main pin is furnished with two grooves by means of which it is kept in
position in the body through the aid of a screw and pin. Two cylindrical pins
placed in borings of the body, which pins are held by. means of springs and screws
to press against the main pin when the protector is closed. In this position the
cylindrical pins keep the main pin fast within the body. When the protector is to
be removed the special key is introduced into the slot of the main pin.
The edge
of the special key pushes against the edge of a small catch or anchor piece turning
round a pin, and an opposite edge of this anchor presses the first of the cylindrical
pins out of the corresponding recess of the main pin. At same time with the motion
of the first cylindrical pin the second cylindrical pin is removed from its corres-
ponding recess by means of an incline or edge of the special key. The main pin is now
allowed to turn by means of the special key into position, so that the protector can
be drawn out of the key-hole by means of the said special key, which is secured in
or holds to the protector in this position by means of the second cylindrical pin,
which is allowed to catch in a slot or opening of the special key through a recess of
the main pin.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Hermann Felix Engel in the Great Seal Patent Office on
the 27th May 1879.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. " AN IMPROVED KEY-HOLE PROTECTOR." A con-
nunication from Wilhelm Colshorn, of Hamburg, in the German Empire.
This Invention relates to improved apparatus to be used as a key-hole protector
and consists of the introduction of a metal plug or lock piece, in shape similar to
the pin and bit of a common key, into the key-hole of locks, and in fastening this
arrangement to the cover plate of the lock by means of a special key. By this
means the key-hole is locked up and the lock rendered unpickable. For opening
the lock the protector must be removed by means of the special key belonging to
same and then the lock can be opened by the corresponding key.
In order that the said Invention may be well understood there is annexed hereto
a Sheet of Drawings illustrative thereof, wherein this key-hole protector apparatus
is shown full size in details and the application thereof to a door lock of common
construction. A is the door; B, the lock, with the cover plates c and d; C is the
key-hole at both sides of the door; D is the body of the protector, similar in shape
to the bit of a key, and represented in Fig. 1 in the position as when inserted in the
key-hole of the closed lock. In the body D a pin E, furnished with a projection e
at its outer end, is placed, this pin having a slit or notch for the reception of the
special key G. Fig. 1 shows the protector in open position as when inserted in the
key-hole, while Fig. 5 shows the protector when closed, in which position the pin
E has been turned by means of the key G and the projection e placed behind the
cover plate d of lock B. From this closed position the protector can only be
removed after the projecting pin E has been turned sufficiently by means of the
special key G to allow the projection e to pass out through the key-hole C.
The special construction of this protector, as shown in the accompanying Drawings,
is as follows:-
The main pin E is furnished with two grooves and 8, by means of which it is
kept in position in the body D by the aid of a screw o and pin p. Two cylindrical
pins i, ¹, are placed in borings of body D, which pins are held by means of springs
and screws, as shown in Figs. 1, 5, and 8, to press against the main pin E when the
protector is closed, as shown in Fig. 5. In this position the cylindrical pins i, i¹,
keep the main pin E fast in the body D. When the protector is to be removed
the special key G is introduced into the slot of the main pin E in the position
shown in Fig. 9. The edge f of the special key G pushes against the edge x of a
small catch or anchor piece turning round a pin, and an opposite edge of this anchor
presses the first of the cylindrical pins i out of the corresponding recess of the main
pin E. At same time with the motion of the first cylindrical pin the second
cylindrical pin ¹ is removed from its corresponding recess by means of the slanting
edge or incline t of the special key G. The main pin E is now allowed to turn
by means of the special key G into the position shown in Fig. 1, and in this position
the protector can be drawn out of the key-hole by means of the said special key G,
which is secured in or holds to the protector in this position by means of the second
cylindrical pin i¹ which is enabled to catch in a slot or opening h of the special key
G through the recess u of the main pin E, as shown in Figs. 3 and 5. p and lact
as adjusting pins.
In conclusion it may be remarked that in fitting to locks having different shaped
openings and fittings certain exterior and merely mechanical modifications or
alterations of the apparatus may be necessary and will be readily effected by any
ordinary workman acquainted with locksmith's work.

page_text: Having now described the nature and particulars of the said Invention in such
wise that the same may be readily carried into practice, I claim,―
A key-hole protector with a movable pin which can be turned by means of a
special key whereby and in consequence of which a projection of the pin catches
behind a cover plate of the lock, protecting the key-hole and rendering the lock
unpickable, all substantially as herein set forth and as shown by the Drawings.
In witness whereof, I, the said Friedrich Hermann Felix Engel, have hereunto
set my hand and seal, this Twentieth day of May, in the year of our Lord
One thousand eight hundred and seventy nine..