U.S. patent number 3,603,983 [Application Number 04/844,103] was granted by the patent office on 1971-09-07 for mechanical-electrical code generating device employing fluid switching.
This patent grant is currently assigned to Northern Electric Company Limited. Invention is credited to William Mitchell.
United States Patent |
3,603,983 |
Mitchell |
September 7, 1971 |
MECHANICAL-ELECTRICAL CODE GENERATING DEVICE EMPLOYING FLUID
SWITCHING
Abstract
A mechanical-electrical code generating device in which a
plurality of closed, fluid carrying tubes, each having pressure
responsive means for producing a unique electrical signal, are
selectively compressible to generate a selected pattern of
signals.
Inventors: |
Mitchell; William (Ottawa,
Ontario, CA) |
Assignee: |
Northern Electric Company
Limited (Montreal, Quebec, CA)
|
Family
ID: |
25666135 |
Appl.
No.: |
04/844,103 |
Filed: |
July 23, 1969 |
Current U.S.
Class: |
341/34; 178/17C;
200/83J; 200/83Z; 235/200R; 200/81.4; 235/145R; 235/201R |
Current CPC
Class: |
G06C
7/02 (20130101); H03K 17/967 (20130101); F15C
1/001 (20130101); H01H 3/24 (20130101) |
Current International
Class: |
H03K
17/967 (20060101); H03K 17/94 (20060101); F15C
1/00 (20060101); H01H 3/00 (20060101); H01H
3/24 (20060101); G06C 7/02 (20060101); G06C
7/00 (20060101); G08c 019/00 () |
Field of
Search: |
;340/365,337
;200/61.42,81,81.4,81.5,81.9 ;235/145R,146,200,201 ;178/17G,79 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Richardson; Robert L.
Claims
I claIm:
1. A mechanical-electrical code generating device comprising:
a plurality of substantially parallel, contiguous, transversely
resilient, closed tubes, each of the tubes carrying a
noncompressible fluid;
means responsive to a change of pressure of the fluid in each of
the tubes to produce, for each tube, an electrical signal; and
a plurality of actuating means positioned transversely to the tubes
and each adapted to compress the tubes selectively whereby the
pressure responsive means is actuated.
2. A device as claimed in claim 1 in which the actuating means
comprises a key having a member positioned transversely to the
tubes and crenellated to provide slots receiving the tubes, the
slots being of different lengths for selectively compressing the
tubes on depression of the key.
3. A device as claimed in claim 2 in which the crenellated member
comprises a plate slidable in the key and movable against
compressive means mounted on the key and remote from the slots, the
compressive means being yieldable when the selected tubes have been
compressed, and including a closed, transversely resilient strobe
tube carrying a noncompressible fluid and compressible by the key
when the compressive means yields, the strobe tube having means
connected therewith adapted to produce an electrical signal on
compression of the strobe tube by the key.
4. A device claimed in claim 1 in which the pressure-responsive
means comprises a plurality of pressure-actuated switches, one
switch being connected with each of the tubes.
5. A device as claimed in claim 1 including a closed, transversely
resilient bumper tube actuable by any of the actuating means and
substantially filled with a noncompressible fluid whereby only one
of the actuating means is operable at one time.
6. A device as claimed in claim 1 including a closed, transversely
resilient strobe tube carrying a noncompressible fluid and actuable
by any one of the actuating means, and means responsive to a change
in pressure of the fluid in the strobe tube to produce an
electrical signal, the strobe tube being actuable after the
selected ones of the plurality of tubes have been compressed.
7. A mechanical-electrical device for the digital selection of
coded electrical signals, comprising:
a plurality of transversely resilient, closed tubes lying in
parallel relationship one with another, each of the tubes carrying
a noncompressible fluid therein;
a keyboard having a plurality of keys each having a member located
transverse to the tubes and crenellated to receive the tubes one in
each slot formed thereby, the slots being of a selected pattern of
lengths whereby on depression of the key and movement of the member
transverse to the tubes selected ones of the tubes are
simultaneously compressed; and
means actuable on a change of pressure of the fluid in each of the
tubes to generate a code unique to the selected combination of
tubes compressed.
8. A mechanical-electrical device for the digital selection of
coded electrical signals, comprising:
a housing having a base portion and a keyboard mounted on the base
portion;
a plurality of transversely resilient, closed tubes lying in
parallel relationship in a common plane and supported by the base
portion of the housing, each of the tubes carrying a
noncompressible fluid therein;
a plurality of keys mounted on the keyboard, each key having a
member positioned transverse to the tubes and crenellated to
receive the tubes one in each slot formed thereby, the slots being
of a selected pattern of depth whereby on depression of the key and
movement of the member across the plane of the tubes selected ones
of the tubes are simultaneously compressed; and
a plurality of pressure-actuated switches one connected with an end
of each of the tubes and actuable on a change of pressure of the
fluid in each of the tubes to generate a code unique to the
selected combination of tubes compressed.
9. A device in claim 8 including compressive means mounted on the
key and bearing against the crenellated member remote from the
slots, the crenellated member being slidable in the key and the
compressive means being yieldable when the selected tubes have been
compressed, and a closed, transversely resilient strobe tube
supported by the base portion of the housing and carrying a
noncompressible fluid, the strobe tube being compressible by the
key when the compressive means yields and having means connected
therewith adapted to produce an electrical signal on compression of
the strobe tube by the key.
10. A device as claimed in claim 9 in which the key comprises a cap
having a chamber therein and a guide member mounted on the cap, the
crenellated member being slidable in the guide member and into the
chamber, and the compressive means comprises a compression spring
mounted in the chamber with one end of the spring bearing against
the cap and the other end of the spring bearing against the
crenellated member, the guide member having a shoulder engageable
with the strobe tube on compression of the spring.
11. A device as claimed in claim 8, including a closed,
transversely resilient bumper tube supported by the base portion of
the housing the bumper tube being compressible by any one of the
keys and being substantially filled with a noncompressible fluid
whereby only one the keys is operable at one time.
Description
The present invention relates to a mechanical-electrical code
generating device and more particularly to the digitally selective
generation of coded electrical signals.
In the manual transcribing of information onto paper it is usual to
use a keyboard, for example a typewriter. The same keyboard concept
has been used to transduce mechanical energy into electrical energy
for information storage and transmission, for example in a teletype
machine. Keyboards presently in use for the mechanical-electrical
transduction of energy are relatively expensive to produce and
maintain. Furthermore, variations in the arrangement of the keys on
the keyboard are obtainable only at considerable further
expense.
It is an object of the present invention to provide an improved
device, using fluid-pressure means, for the digitally selective
generations of coded electrical signals.
It is another object of the invention to provide an improved
keyboard device for generating a unique code for each operated
key.
A further object of the invention is to provide a keyboard device,
for generating coded electrical signals, in which the replacement
of keys is simplified.
An example embodiment of the invention as shown in the accompanying
drawings in which:
FIG. 1 is a schematic plan view of a keyboard employing the present
invention;
FIG. 2 is a face view in elevation taken along the line 2--2 of
FIG. 1, showing a key and tube arrangement;
FIG. 3 is a side view in elevation taken along the line 3--3 of
FIG. 2;
FIG. 4 is a view similar to FIG. 2 showing the key depressed to
generate a coded signal and a bumper tube;
FIG. 5 is a side view in elevation taken along the line 5--5 of
FIG. 4, showing in phantom the further depression of the key to
generate a strobe signal;
FIG. 6 is a side view of a pressure-actuated switch for use with
the invention, connected to a signal tube; and
FIG. 7 is a side view in elevation showing a bumper tube.
In the drawings, FIG. 1 shows a keyboard 10 comprising a housing 11
carrying on its upper portion a faceplate 12 and rows of keys or
pushbuttons 13, for example as used in teletype operations. As
shown in FIGS. 2 and 3, each key 13 is loosely retained in an
aperture 14 of faceplate 12 and projects both above and below the
faceplate with the upper projecting portion carrying indicia.
A belt 15 underlies faceplate 12 within housing 11 and consists of
a plurality of closed signal tube 16 lying parallel one to another
in a horizontal plane and each terminating in a fluid-actuated,
pressure-sensitive switch 17. As seen in FIG. 1, belt 15 follows a
sinuous path in order to pass beneath all keys 13 of keyboard
10.
As shown in FIGS. 2 and 3 of the drawings, key 13 comprises a cap
18 resting in aperture 14, and a key plate 19 extending downwardly
from the cap into lower portion 20 of housing 11 and transverse to
belt 15. Cap 18 consists of an inverted cup 21 having a
circumscribing lip 22 which engages the underside of faceplate 12,
and a guide member 23 fixed to cup 21 to form a chamber 24 in the
cap. Guide member 23 projects downwardly to form a shoulder 25. Key
plate 19 slides vertically in a slot 26 formed in member 23 and in
the wall of chamber 24, and is urged downwardly by compressive
means comprising a compression spring 27 which bears at one end
against a depression 28 in the bottom of cup 21 and at the other
end against a shoulder 29 on the key plate. A vertical slot 30 is
carried by key plate 19 and accommodates a pin 31 mounted in member
23 transverse to slot 30, which retains the key plate in slot 26
against the action of spring 27.
The lower portion of key plate 19 is crenellated to provide a
plurality of fingers 32 defining slots 33 of two different lengths
in predetermined sequence, the sequence being different for each
key. Each slot 33 accommodates a tube 16 of belt 15 which rests in
a passage 34 in lower portion 20 of housing 11. Fingers 32 of key
plate 19 are vertically slidable, along with the lower portion of
the key plate, in a slot 35 in body portion 20 which terminates at
its lower end in a further passage 36 carrying a bumper tube 37.
One of fingers 32, preferably a central finger 32a, is positioned
to move against bumper tube 37 which runs parallel to belt 15 and
beneath the belt. Bumper tube 37 is sealed at both ends as shown in
FIG. 7, and is filled with noncompressible fluid in an amount which
allows squeezing of the tube by only one key at a time. A strobe
tube 38 rests on base portion 20 of housing 11 above belt 15 and
parallel to it, and passes through a vertical slot 39 in each key
plate 19.
In the described embodiment, central finger 32a rests against
bumper tube 37 and hence key 13 rides on the bumper tube when the
key is in a position of rest. Compression spring 27 is of
sufficient stiffness to yield only after tubes 16 have been
compressed by key plate 19 and, conversely, tubes 16 are of
sufficient transverse resilience that they yield to compression by
key plate 19 before spring 27 yields. Bumper tube 37 must be of
sufficient transverse stiffness to hold each key 13 in a position
of rest but resilient enough to yield to compression by one key.
Each tube 16 is closed at both ends, one end terminating in a
flexible membrane 40 which contacts a plunger 41 in fluid-actuated
switch 17, as seen in FIG. 6. Plunger 41 in turn bears against a
spring contact 42 of a pair of normally open contacts 43 of switch
17. Tube 16 is filled with a noncompressible fluid 44 such as water
(i.e. noncompressible under normal operating pressure of key 13).
Strobe tube 38 is also closed and filled with noncompressible
fluid, and carries a pressure-sensitive switch 17 at one end, in
the same manner as tubes 16 shown in FIGS. 6 of the drawings.
In the operation of cause example embodiment, the depression of a
key 13 will cause certain of tubes 16 to be squeezed as shown in
FIGS. 4 and 5, leaving the remainder of the tubes unaffected. The
squeezing of any one of tubes 16 by its associated key plate 19
displaces fluid 44 laterally in the tube and the pressure of
displacement acts against membrane 40 to force plunger 41 against
spring contact 42, thus closing contacts 43 of switch 17. The
depression of key 13 at the same time squeezes bumper tube 37 as
shown in FIG. 4, 5 and 7. Because bumper tube 37 is sealed at both
ends and can be compressed only to a certain extent, not more than
one key 13 can be depressed at any one time, thus preventing
overlapping signals from being generated in switches 17.
Because of the resistance of tubes 16 and 17 after they have been
squeezed, the further depression of key 13 causes further
compression of spring 27 and brings shoulder 25 of member 23 into
contact with strobe tube 38. Continued downward depression of key
13, and increased compression of spring 37 during completion of the
key stroke, causes the strobe tube 38 to be squeezed by shoulder 25
of member 23, as seen in phantom lines in FIG. 5 of the drawings,
and a strobe signal is generated to indicate that the operation of
the key is completed. The presence of the strobe signal also
indicates that the code signal corresponding to the operated key
should be read from the state of all switches 17 associated with
tubes 16 during the time that the strobe signal is present. This
ensures that false code signals are not generated due to partial
key operations which operate some of the switches 17 associated
with tubes 16 but which are not sufficient to generate the strobe
signal.
By providing different patterns of slots 33 in keys 13, different
signal patterns may be generated in switches 17. The example
embodiment described above, illustrated key 13 generates an 8-bit
code with the pattern of FIG. 4 signalling 10101011 to identify the
particular character carried by the face of that key.
It will be seen that the device of the present invention enables
keys 13 to be arranged in any suitable manner since each key
generates a unique code when operated. For the same reason
individual keys 13 can be removed and replaced in keyboard 10
without any adjustment in base portion 20 carrying tubes 16 in
housing 11 and this allows the keyboard to be adapted to any
desired code arrangement with little expense in parts and
labor.
* * * * *