IMPROVEMENTS IN OR ADDITIONS TO POCKET KNIVES
Year: 1883

page_text: . LETTERS PATENT to John Henry Johnson, of 47 Lincolns Inn Fields in the
"
County of Middlesex, Gentleman for an Invention of "IMPROVEMENTS IN OR
ADDITIONS TO POCKET KNIVES communicated to him from Joseph Thurnauer
and Company, residing at Paris in the Republic of France, Merchants.
>
Void by reason of the Patentee having neglected to file a Specification in
pursuance of the conditions of the Letters Patent.)
.
}
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 19th July 1883.
"
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN OR ADDITIONS TO POCKET KNIVES a communi-
cation to me from Joseph Thurnauer and Company residing at Paris in the
Republic of France Merchants
This Invention relating to improvements in or additions to pocket knives has for
its object the combination in the manner and for the purpose hereinafter described
of a knife or cutting instrument arranged in the same manner as an ordinary
pocket knife with a sliding device or instrument for measuring thickness or
external diameter.
In carrying out this invention the handle of the pocket knife to which the said
Invention is applied is constructed with a recess for the reception of a measuring
instrument hereinafter described which instrument may be arranged to either slide
longitudinally in the recess or to shut down into the recess in a similar manner to
the blade of the knife or may be connected to the knife in any other suitable
manner.
According to the former or sliding arrangement a recess or space is formed or
provided in or on the inner side of one of the cheeks or side plates of the handle
for the reception of the measuring instrument consisting of a graduated bar or rod
which is provided at one extremity which protrudes at one end of the handle with

page_text: a foot or projection presenting a flat surface standing out at right angles with the
sides or edges or both sides and edges of the bar and exactly parallel to a corre-
sponding flat surface formed on the end of the handle of the knife so that the
adjacent surfaces on the foot and on the knife handle are truly perpendicular to
the axis of the rod or bar. The other extremity of the bar is contained within the
handle and is provided with a stop such as a projection, pin or stud sliding in a
corresponding groove or slot for the purpose of preventing the graduated bar
from being accidentally pulled out too far.
When the graduated bar is caused to slide longitudinally in the recess in the
knife handle the perpendicular surface hereinbefore described at the extremity of
the bar is moved away from the corresponding surface on the knife handle. The
object whose thickness or diameter is to be measured is then placed between these
two surfaces which are then adjusted by sliding the bar in the handle until both of
the said surfaces that is to say the surface on the extremity of the knife handle and
the surface on the bar are both brought in contact with opposite sides of the said
object the length of the space between these two surfaces may then be read off on
the scale and represents the diameter or thickness of the object. The measuring
device thus combined with the knife handle acts in a similar manner to an ordinary
rule with perpendicular slider or instrument for measuring diameter or thickness
and is employed in a similar manner to this instrument. When the graduated bar
is pushed back into the handle the knife is ready to be used as an ordinary pocket
knife.
When the graduated bar in place of sliding in the handle is hinged to the latter
in a similar manner to the blades of the knife and shuts into a suitable recess in'
the handle the said bar is provided in addition to the perpendicular foot herein-
before described with a slider with or without a vernier and slide for performing
calculations and presenting a straight perpendicular surface corresponding to the
surface on the foot. In this case the object to be measured is placed between the
two surfaces and its diameter or thickness ascertained by pushing the slider along
the bar so as to bring the surfaces in contact with the object and the reading off
the indications on the bar. When the measuring instrument is not in use the
slider is pushed to one extremity of the graduated bar and the latter is then shut
down into the recess provided for its reception in the handle.