Improvements in or relating to Interlocking Devices for Preventing the Simultaneous Operation of Two or more Levers of a Type- writer or other Mechanism.
Year: 1898

page_text: Date of Application, 5th July, 1898-Accepted, 10th Sept., 1898
Improvements in or relating to Interlocking Devices for Preventing
the Simultaneous Operation of Two or more Levers of a Type-
writer or other Mechanism.
A communication from CHARLES SEARS, Manufacturer, of 1047, East Madison
Avenue, Cleveland, Ohio, United States of America.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The invention relates to interlocking devices adapted to prevent the concurrent
operation of more than one of a plurality of independent levers. The invention is
adapted to a wide variety of uses, but it was originally designed to prevent the con-
current operation of two or more of the key levers of a typewriter or analogous
machine, wherefore the drawing has been inade to show the invention when con-
structed and arranged particularly for such purpose.
The invention consists in the construction and combination of parts hereinafter
described and claimed.
In the drawing, Figure 1 is a sectional front elevation of a plurality of type writer
levers and the new mechanism for preventing the simultaneous operation of two or
more such levers.
Fig. 2 is a similar view of the same parts, showing them in different relative
positions.
Fig. 3 is a plan view of the same parts.
Referring to the parts by letters, À A represent a plurality of independent levers ;
which, as before stated, are, in the particular construction shown, the key levers of a
type writer, matrix machine or other analogous device. There may be any number
of these levers, and they may be of any form.
B represents a tube which extends transversely across all of the levers and upon
that side thereof toward which they move when they are moved from their normal
position. The tube is below the levers in the construction shown, because they move
downward when they are operated.
A number of steel balls are placed in this tube, by which they are maintained in
line. The balls are free to move in either direction within the tube, but their
motion is limited by stops b b at the ends of the tube. These stops, in the con-
struction shown, are adjustable plugs which screw into the ends of the tube. There
will preferably be one more ball than there are levers; and the total amount of free
space between all of the balls and the stops is only slightly greater than the diameter
of the levers or such devices, carried by the levers, as are intended to be passed
between the balls when the levers are operated.
On the underside of each lever, as shown, is secured a pin a.
These pins pass
into the tube through perforations b¹ therein, when the levers are actuated, and in so
doing pass between two of the balls C. The balls upon opposite sides of the pin so
moved into the tube, are moved to right and left respectively toward the stops b b and
into contact with one another. The friction incident to this movement is very

page_text: slight and does not sensibly impede the operation of the levers. When one pin has
passed between two of the balls, as shown in Figure 2, it is obvious that if an attempt
were made to actuate another lever, its pin would strike one of the balls; and since
said ball is, for the time being, practically immovable, the operation of the lever is
prevented. When any lever, in the embodiment of the invention shown, is moved to
the end of its normal path, its pin enters a hole 6 in the opposite side of the tube,
whereby the bending of the said pin, by pressure upon another lever, is practically
impossible.
2
If an attempt is made to simultaneously operate two levers, their pins simul-
taneously strike balls, the balls between the pins being thereby moved into close
contact. But this movement of said balls in either direction can not be equal to half
the diameter of the pins, wherefore the movement of both levers is checked.
It is therefore impossible to move any lever until all of the others have returned to
their normal position; and it is likewise impossible to operate two levers at the same
time.
For obvious reasons, it is preferred to employ balls which. are accurate. spheres, as
the locking members. The construction might be operative, however, if these
members were rings, or perhaps elipsoidal bodies, and the term balls herein is
intended to be taken as including such and similar forms.
Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondent and in what manner
the same is to be performed, I declare that what I claim is :-
1. The combination of a plurality of levers and pins projecting severally from said
levers, a tube secured transverse to the levers and in the plane of said pins and having
holes through which the pins project into said tube and by which the pins are guided
and prevented from swerving longitudinally of the tube, a plurality of freely movable
balls in said tube, and means for limiting the sum of play between the balls to an
amount substantially equal to the thickness of one pin, substantially as specified.
2. The combination of a plurality of levers A, a pin projecting from each lever, a
tube B supported in a position transverse to the levers and having holes through
which said pins enter the tube, freely movable balls in said tube, and a screw plug
in the end of said tube, for limiting the movement of the balls substantially as
⚫ specified.
3. The combination of a plurality of levers A, a pin rigidly secured to each lever, a
tube B supported in a position transverse to the levers and having the holes 61 62 for
embracing and guiding the pins, a plurality of freely movable balls in said tube, and
means for limiting the play of the balls, substantially as specified.
Dated this 27th day of June 1808