U.S. patent number RE32,419 [Application Number 06/822,866] was granted by the patent office on 1987-05-12 for molded keyboard and method of fabricating same.
This patent grant is currently assigned to Engineering Research Applications, Inc.. Invention is credited to Craig E. Rooney.
United States Patent |
RE32,419 |
Rooney |
May 12, 1987 |
Molded keyboard and method of fabricating same
Abstract
A moldable, impulse operation synthetic resin keyboard, and a
method of fabricating the same, are provided wherein the keyboard
achieves essentially standard, tactile feed and feedback,
mechanical N-key rollover protection and precise, reliable output.
The keyboard includes a synthetic resin base plate having a
plurality of elongated, cantilever mounted flippers, along with a
plurality of elongated, laterally spaced, inwardly and opposedly
extending, pivotal, key-supporting arms. Upon depression of a key,
the associated flipper is deformed until a release point is
reached, whereupon the flipper is disengaged, allowing the flipper
to quickly return to its rest position. A keyboard output is
developed as the flipper, during overtravel thereof past its rest
position, strikes a signal-generating assembly.
Inventors: |
Rooney; Craig E. (Prairie
Village, KS) |
Assignee: |
Engineering Research Applications,
Inc. (Prairie Village, KS)
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Family
ID: |
27225896 |
Appl.
No.: |
06/822,866 |
Filed: |
January 27, 1986 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
244054 |
Mar 16, 1981 |
04359613 |
Nov 16, 1982 |
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Current U.S.
Class: |
200/5R; 235/145R;
341/27; 400/472; 400/477 |
Current CPC
Class: |
H01H
11/00 (20130101); H01H 13/70 (20130101); H01H
2215/028 (20130101); H01H 2215/034 (20130101); H01H
2217/012 (20130101); H01H 2239/026 (20130101); H01H
2227/036 (20130101); H01H 2229/046 (20130101); H01H
2233/004 (20130101); H01H 2233/006 (20130101); H01H
2225/016 (20130101) |
Current International
Class: |
H01H
11/00 (20060101); H01H 13/70 (20060101); H01H
013/70 () |
Field of
Search: |
;84/1.15,DIG.7
;178/17A,17R,79,33R ;179/19R
;200/1R,5R,5A,5E,17R,67D-67DB,153R,159A,159B,160,308,329,330,339,340
;400/80,52,62,104,164.2,187,466,472,477-479,481,495,495.1,666
;235/145R ;310/330 ;340/345,365R,365A,365E,365P,365S |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1070231 |
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Jun 1967 |
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GB |
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1171082 |
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Nov 1969 |
|
GB |
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1330742 |
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Sep 1973 |
|
GB |
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1348007 |
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Mar 1974 |
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GB |
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1386070 |
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Mar 1975 |
|
GB |
|
1420581 |
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Jan 1976 |
|
GB |
|
1468036 |
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Mar 1977 |
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GB |
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Other References
N K. Perkins, et al., "Molded Spring Keyboard", IBM Technical
Disclosure Bulletin, vol. 23, No. 10, pp. 4548-4549, 1981, New
York. .
Popular Science; Free, John; "Electronic Typewriter Has Ultrasonic
Keyboard"; Mar., 1981; p. 75. .
IBM Technical Disclosure Bulletin; Lynott, J. J.; "Photo Keyboard";
vol. 3, No. 11, Apr. 1961, p. 44. .
IBM Technical Disclosure Bulletin; Taris, J. A.; "Keyboard"; vol.
8, No. 8, Jan. 1966, p. 1064. .
Electrical Design News (EDN); "Reliable and Flexible Keyboards
Feature Optical Input Detection"; Apr. 5, 1980, p. 146. .
Electrical Design News (EDN); Larson, Willis; "Effective Membrane
Switches Need More Than Good Looks"; Jan. 20, 1980, p. 147. .
HI-TEK Keyboards catalog; 4 pages. .
SABRECOIL.RTM. Keyboard catalog; Mechanical Enterprises, Inc., 8
pages. .
Reprint from Dupont Magazine, vol. 73, No. 6; Nov.-Dec. 1979 issue;
Chromerics, Inc.; "Keyboards by the Mile", 8 pages. .
K-B Denver Inc., Tactile Switch Keyboard catalog, Oct. 1979, 7
pages. .
STACKPOLE Keyswitches, Keyboards and Arrays (Preliminary Data
Sheet), 9-1979, 3 pages. .
TEC, Inc.; Your Complete Source for Keyboards; 9-1979; 5 pages.
.
Product Index & Directory, eem/1977, pp. 224, 1480, 2671, 3999,
4000, 4065, 4082, 4083, 4154, 4155, 4158, 4184, 4227 and
4310..
|
Primary Examiner: Scott; J. R.
Attorney, Agent or Firm: Schmidt, Johnson, Hovey &
Williams
Claims
I claim:
1. A keyboard, comprising:
a plurality of keys;
shiftable means supporting said keys for individual, selective
depression thereof .Iadd.and comprising an elongated arm secured to
each key respectively, and means mounting said arms for pivotal
movement thereof some of said arms being of a different length than
others of said arms; .Iaddend.
an engagement surface operably coupled and shiftable with each of
said keys;
an elongated, deflectable, resilient flipper associated with each
key and having a striking portion and a rest position;
selectively actuatable means for generating an electrical output
signal upon striking thereof and located adjacent said flipper
striking portions;
means mounting each of said flippers for engagement thereof by the
engagement surface coupled with said associated key, upon
depression of the associated key, in order to shift said striking
portion of said flipper away from said signal-generating means;
structure for releasing each of said flippers from the engagement
surface coupled with the associated key, when the striking portion
of the flipper has been shifted away from said signal-generating
means a predetermined distance,
each of said flippers being constructed and arranged for, upon said
release thereof, rapidly and freely shifting the striking portion
thereof toward said signal-generating means in a manner to
overtravel the rest position of the flipper and thereupon strike
and actuate said signal-generating means, and for thereafter
shifting said flipper back to the rest position thereof after said
striking and actuation of the signal-generating means, the duration
of contact time between said flipper striking portions and said
signal-generating means being independent of the duration of
depression of the corresponding keys,
said shifting of said flipper striking portion upon said release of
the flipper being independent of any subsequent movement of the
corresponding key.Iadd.,
said signal-generating means comprising
electrical switch means including a plurality of electrically
conductive elements operably associated with said keys for directly
providing a unique, distinctive output signal for each of said
particular keys upon depression thereof, the number of said
elements being less than the number of said keys.Iaddend.. .[.
2. A keyboard as set forth in claim 1, said shiftable means
comprising an elongated arm secured to each key respectively, and
means mounting said arms for pivotal movement thereof..].
3. A keyboard as set forth in claim .[.2.]. .Iadd.1.Iaddend., each
of said arms being oriented above the corresponding flipper.
4. A keyboard as set forth in claim .[.2.]. .Iadd.1.Iaddend., said
flipper mounting means comprising structure for mounting of the
flippers in a cantilever fashion, with said striking portion of
each of the flippers being adjacent the end thereof remote from the
cantilever mounting.
5. A keyboard as set forth in claim .[.2.]. .Iadd.1.Iaddend., the
pivot axes of said arms being spaced from and above the
corresponding arm.
6. A keyboard as set forth in claim 1, said shiftable means
comprising a pivotal element operatively coupled to each of said
keys, said release structure including a clearance surface adjacent
said engagement surface, said engagement surface being configured,
upon pivoting of the associated element, for clearing the
associated flipper and allowing the same to move along said
clearance surface to the rest position of the flipper.
7. A keyboard as set forth in claim 1, said signal-generating means
comprising an elongated resistive wire, and a conductive element
adjacent said wire, said conductive element being located for
engagement by said striking portions of said flippers during said
overtravel shifting thereof for causing the conductive element to
impinge upon the wire.
8. A keyboard, comprising:
a plurality of keys;
means supporting said keys for selective depression and return
movement thereof,
including an elongated, generally horizontally extending arm
secured to each key respectively, .Iadd.some of said arms being of
a different length than additional ones of said arms, .Iaddend.
at least certain of said arms extending in a first direction,
others of said arms extending in a second direction different than
said first direction; and
means mounting each of said arms for pivotal movement thereof about
generally horizontal axes spaced from the associated key; and
means for developing a keyboard output corresponding and in
response to depression of particular keys.Iadd.,
said output developing means comprising electrical switch means,
said switch means including a plurality of electrically conductive
elements operably associated with said keys for directly providing
a unique, distinctive output signal for each of said particular
keys upon depression thereof, the number of said elements being
less than the number of said keys.Iaddend..
9. A keyboard as set forth in claim 8, said keys being oriented in
respective rows thereof, the arms secured to the keys of one row
thereof extending in said first direction, the arms secured to the
keys of another row thereof extending in said second direction.
10. A keyboard as set forth in claim 8, said first and second
directions being substantially opposite one another.
11. A keyboard as set forth in claim 8, said mounting means
comprising:
a pair of spaced, opposed, upstanding sidewalls respectively
located adjacent the ends of said certain arms and said other arms
remote from the secured keys;
pivotal connection structure pivotally securing the adjacent arm
ends to said sidewalls; and
means for limiting the pivotal travel of each of said arms to a
predetermined arc.
12. A keyboard as set forth in claim 11, said axes lying in
horizontal planes which intersect said arcs.
13. A keyboard as set forth in claim 11, said travel-limiting means
comprising a dog carried by each arm, and structure defining a
dog-receiving opening proximal to the base of the adjacent
sidewall.
14. A keyboard, comprising:
a plurality of keys arranged in at least two proximal rows;
means supporting said keys for selective depression and return
movement thereof, comprising
an elongated, generally horizontally extending arm secured to each
key respectively and having an engagement surface thereon,
first arms secured to the keys of one of said rows extending in a
first direction,
second arms secured to the keys of another of said rows extending
in a second direction generally opposed to said first
direction;
means mounting said first arms for independent pivotal movement
thereof about a first axis spaced from the keys secured to the
first arms and above the first arms, and for limiting the pivotal
movement of the first arms to a predetermined first arc, said first
axis lying in a first horizontal plane which intersects said first
arc; and
means mounting said second arms for independent pivotal movement
thereof about a second axis spaced from the keys secured to the
second arms and above the second arms, and for limiting the pivotal
movement of the second arms to a predetermined second arc, said
second axis lying in a second horizontal plane which intersects
said second arc;
means for developing a keyboard output corresponding to the
depression of particular keys; and
structure operably coupling said keys and output means,
comprising
an elongated, deflectable, resilient flipper for each of said arms
and having a rest position;
means mounting first flippers associated with said first arms in a
cantilever fashion with the free ends of the first flippers
extending to a point for engagement by said surfaces on the first
arms, when the keys mounted on the first arms are depressed, in
order to deflect the first flippers;
means mounting second flippers associated with said second arms in
a cantilever fashion with the free ends of the second flippers
extending to a point for engagement by said surfaces on the second
arms, when the keys mounted on the second arms are depressed, in
order to deflect the second flippers; and
structure for releasing each of said first and second flippers from
the corresponding engagement surfaces when the flippers have been
deflected a predetermined amount, and for thereafter permitting the
flippers to return to the rest positions thereof,
said output means including apparatus for sensing the movement of
said flippers.Iadd.,
said output means comprising
electrical switch means including a plurality of electrically
conductive elements operably associated with said keys for directly
providing a unique, distinctive output signal for each of said
particular keys upon depression thereof, the number of said
elements being less than the number of said keys.Iaddend..
15. A keyboard as set forth in claim 14, said engagement surfaces
being disposed above the free ends of the corresponding
flippers.
16. A keyboard as set forth in claim 14, said release structure
including a clearance surface adjacent said engagement surface,
said engagement surface being configured, upon pivoting of the
associated element, for clearing the associated flipper and
allowing the same to move along said clearance surface to the rest
position of the flipper.
17. A keyboard as set forth in claim 14, said apparatus comprising
an elongated resistive wire, and a conductive element adjacent said
wire, said conductive element being located for engagement by said
flippers during said return thereof to their rest positions for
causing the conductive element to impinge upon the wire.
18. In a keyboard:
an elongated .Iadd.continuous .Iaddend.output member having a
plurality of spaced electrical contact switch zones along the
length thereof;
a plurality of .Iadd.elongated .Iaddend.elements respectively
associated with said switch zones, each of said elements having an
contact switch area thereon configured for engaging the associated
switch zone of said member;
means mounting said elements adjacent said output member .Iadd.and
transversely relative to the longitudinal axis of the output
member, .Iaddend.with the switch areas of the elements being
normally spaced from said associated switch zones;
means for selective movement of said elements such that the switch
areas thereof contact the associated switch zones, said output
member including structure for generating a respective electrical
output signal in response to the contact of each of said element
switch areas and the corresponding switch zones, said moving means
including
means for selectively shifting each of the element switch areas
away from the corresponding associated switch zones, comprising a
manually depressible key for each element, and means operably
coupling each key and its corresponding element;
structure for releasing said element switch areas after the same
have been shifted away a predetermined amount,
each of said element switch areas being configured and arranged for
return shifting back toward said associated switch zone and impact
engagement of the associated switch zone, said return shifting and
impact engagement being independent of the duration of depression
of the corresponding key; and
means operably coupled to said output member for determining which
of said switch zones has been impacted. .Iadd.
19. A keyboard, comprising:
a plurality of keys;
means supporting said keys for selective depression and return
movement thereof,
including an elongated, generally horizontally extending arm
secured to each key respectively,
at least certain of said arms extending in a first direction,
others of said arms extending in a second direction different than
said first direction; and
means mounting each of said arms for pivotal movement thereof about
generally horizontal axes spaced from the associated key; and
means for developing a keyboard output corresponding and in
response to depression of particular keys,
said output developing means comprising electrical switch means,
said switch means including a plurality of elongated, electrically
conductive elements operably associated with said keys, said
elements lying within an elongated zone oriented generally
transverse to the longitudinal axes of said arms, said zone having
a width substantially less than the length of said arms. .Iaddend.
.Iadd.20. A keyboard as set forth in claim 19, said plurality of
elements being a pair of said elements. .Iaddend. .Iadd.21. A
keyboard as set forth in claim 19, said zone being beneath said
arms.
.Iaddend. .Iadd.22. A keyboard as set forth in claim 21, said zone
being located between each of said keys and their associated pivot
axes. .Iaddend. .Iadd.23. A keyboard as set forth in claim 8, said
plurality of elements being a pair of said elements. .Iaddend.
.Iadd.24. A keyboard as set forth in claim 8, said elements lying
in an elongated zone oriented generally transverse to the
longitudinal axes of said arms, said zone being located beneath
said arms. .Iaddend. .Iadd.25. A keyboard as set forth in claim 24,
said zone being located between each of said keys and their
associated pivot axes. .Iaddend. .Iadd.26. A keyboard as set forth
in claim 25, each of said arms including integral operating
structure for operating said switch means upon depression of the
respective key supported by the arm. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is concerned with an improved, low cost
keyboard preferably formed of moldable synthetic resin material and
which has a substantial degree of mechanical N-key rollover
protection and other necessary features making the keyboard
applicable for a wide variety of uses. More particularly, it is
concerned with such a keyboard having a momentary impulse output
operation, standard tactile feedback and the ability to handle high
speed inputs without difficulty.
.[.Attention is directed to pending application for U.S. Letters
Patent Ser. No. 06/190,177, Filed: Sept. 24, 1980; this application
is hereby incorporated by reference into the instant
application..].
.Iadd.Attention is directed to application Ser. No. 06/190,177,
Filed Sept. 24, 1980, now U.S. Pat. No. 4,359,612. This patent is
hereby incorporated by reference into the instant application.
.Iaddend.
2. Description of the Prior Art
Keyboards are most commonly associated with typewriters and have
until recent times developed in parallel with typewriter evolution.
However, with the advent of the electronic age, a new generation of
keyboards suitable for use as instruction keys for electronically
activated devices has evolved. These keyboards have a wide array of
uses, only one of which is to input electronic typewriters.
In the present state of the art, there are basically three types of
keyboards. In one variety, electronic output in the form of
electrically encoded signals to a companion or remote device is
employed. In another type of keyboard, mechanical output movements
are used which trip or activate leverages or linkage in either
totally mechanical machines (e.g., manual typewriters) or electric
machines such as electric typewriters. The principal distinguishing
feature between these two types of keyboards is the form of output,
i.e., mechanical movement or electric signal.
The third type of general keyboard construction can be thought of
as a hybrid between the electronic and mechanical units. In this
form, a mechanically induced movement is read electronically by one
of various kinds of transducers, and the reader outputs the
detected movement in the form of signals of an electronic
nature.
While it is true that the keyboard art is old and well developed,
the relatively recent proliferation of electronic devices that
require operator instruction has caused the manufacturing of
keyboards to grow at an enormous rate. Keyboards are required in
all sizes, configurations, colors, shapes, tilts, slants, legends,
codings, key strokes and depths. Despite this industry growth, or
perhaps as a result thereof, no one keyboard or variety of keyboard
has emerged as clearly superior. This is primarily due to the
operational or cost limitations inherent in the various keyboard
constructions, as well as the difficulty of modifying the same for
particular purposes.
For example, in the case of full keystroke keyboards, the depth of
the keyboard structure becomes a problem in many cases. The
standard key switch plunger arrangement or mechanical leverage
linkage consumes a considerable depth, because of the structural
constraints encountered in developing a proper key stroke
(approximately 3/16 of an inch) with acceptable key wiggle, direct
depression travel, proper chassis and mounting cannister for either
the key switch plunger or the leverage that attaches to the key
stem. This in addition to the height of the key top itself
necessitates a rather large, bulky overall keyboard structure.
Because of the foregoing problems, full stroke keyboards are
generally limited to conventional typewriters or input/output
devices, and are not used on other types of equipment. Manifestly,
the problem of providing a full stroke keyboard with minimum depth
has limited the market potential of prior full stroke
keyboards.
Virtually all known keyboards with key stroke capability require
separate key tops. This is a fundamental requirement of the plunger
or lever structure used as the key top support. The present
industry standard for key tops on reliable equipment is double
injection molded synthetic resin key tops. In this form, the key
tops are first molded in one color of synthetic resin and an inner
shell space is allowed for a second color injection that results in
key legending being injected completely through the outer key
shell. This process is inherently expensive in many ways. For
example, it requires two complete injection runs for manufacture of
the keytops, using expensive molding equipment which cannot be
altered except at great expense. The double molding operation also
results in a key top that is of substantial thickness and consumes
a considerable amount of material.
The primary use of full stroke keyboards is in graphics and
typewriting, including computer and CRT units. However, the bulk of
the potential market for typewriter and printer equipment has grown
accustomed to the tactile feel of conventional electric
typewriters. These devices have feedback as a consequence of their
design and mechanical construction. Tactile feedback in this
context refers to a slight pressure increase required to depress a
key through the initial range of key stroke, followed by a
breakaway at about two-thirds of the stroke depth that is felt by
the operator. This breakaway change from one pressure to a lighter
pressure is not mimicked in any electronic keyboard in common
usage, and accordingly this latter type of keyboard is deficient in
this respect. In order to fully meet market demand and appeal to an
already trained public, a keyboard form should include tactile
feedback. Moreover, the amount of feedback should be variable
without significant or costly manufacturing changes, in order to
meet differing uses.
With touch typing at high speed on a conventional typewriter
keyboard a phenomenon occurs which is referred to as "rollover."
While typing at high speed, one key is in initial stages of
depression before the priorly depressed key is released, and in
some cases there could be as many as four keys simultaneously in
various stages of depression, bottom out or upward travel. There
are two ways to handle this problem that are in common use, i.e.,
mechanical blocking or filtering, or electronic scanning or logic
analysis. Typical electric typewriters with keyboards use the
technique of mechanical filtering. In this scheme some form of
continuous chain of elements is configured in such a way that only
one key lever at a time can pass through the chain. In this manner,
no two keys can be in a position to interrupt or actuate a
mechanical movement simultaneously. Because of the relatively high
tolerance requirements of such systems, they are inherently
expensive, can actually retard the speed of the typist, and present
maintenance problems in that they can become gummed up and sticky
over time. The typical electronic keyboard on the other hand solves
the problem in an electronic way. Normally, a keyboard matrix of
the key switch positions is scanned at high frequency. The first
switch to be activated is entered into memory and the second switch
is then entered while the output from the first switch is ignored
or blocked and so forth until "N-keys" are depressed. For this
reason electronic keyboards require a substantial amount of logic
circuitry, the relative amount and sophistication of the decoding
and "N-key" analysis and speed of information scanning being in
direct proportion to the cost of the board.
Another absolute necessity in connection with keyboards is that of
reliability, i.e., the life or number of cycles which can be
expected from the keyboard, and within a given number of cycles,
the number of misses or fault signals that occur. The most
expensive and reliable keyboards on the market today are so-called
"Hall effect" keyboards. In these units key depression closes a
switch which is magnetically sensed, and only a breakdown in the
mechanics of the switch cannister or chassis can effect reliability
of such a device. However, Hall effect keyboards are inherently
very expensive by virtue of the many electronic components
required, and particularly the relatively high electronic power
supply requirements.
In short, it will be appreciated that the various keyboards of the
prior art each possess a number of outstanding attributes, but all
are plagued by one or more serious deficiencies. Accordingly, there
is a real and heretofore unsatisfied need in the art for a simple,
low cost keyboard having the combined properties of full stroke
capability, tactile feedback, N-key roll-over protection, minimum
depth, and a high degree of reliability.
SUMMARY OF THE INVENTION
The present invention is broadly concerned with a keyboard, and a
method of fabricating the same, which overcomes the problems noted
above. The keyboard of the invention includes a plurality of keys
which are individually supported for selective depression thereof,
along with means for developing a keyboard output corresponding to
the depression of particular keys. The keys are operably coupled to
the output means by structure including an elongated, resilient
element for each key and having a shiftable operating portion, and
means operably interconnecting the keys and their associated
elements for shifting of the operating portions of the elements in
response to depression of particular keys. The output means further
include at least one output member adjacent the resilient elements
and located to be engaged by the operating portions of the elements
during shifting thereof. Apparatus is coupled to the output member
for sensing which of the elements has engaged the same, whereupon
the keyboard output is directed to utilization circuitry forming a
part of the overall typewriter and/or printer.
In another aspect of the invention, a keyboard is provided having a
plurality of keys with an elongated, generally horizontally
extending support arms secured to each key respectively. Certain of
the arms extend in a first direction, whereas others of the arms
extend in a second direction different than (preferably generally
opposed to) the first direction. The respective arms are mounted
for pivotal movement thereof about generally horizontal axes spaced
from the associated keys. In this fashion, the keys can be
accommodated within a relatively narrow space, while at the same
time providing the desirable keyboard "feel" and feedback of
conventional typewriter keyboards.
In the most preferred form of the invention, the key-supporting
arms include an engagement surface which, upon depression of the
associated key, engage and deflect a resilient, synthetic resin
element such as a flipper provided beneath each key in the keyboard
base. The respective flippers are mounted in a cantilever fashion
on the keyboard base with the free or operating ends of the
flippers extending beneath the corresponding engagement surfaces.
During depression of a key and consequent downward deflection of
the associated flipper, the latter is deformed and experiences an
increase in potential energy. The engagement surface and flipper
end are cooperatively configured such that, near the bottom of the
key stroke, the flipper is detended from the engagement surface and
is allowed to rapidly shift or spring upwardly toward its original
rest position. However, during this return travel, the flipper
overtravels to a certain extent before returning to its rest
configuration.
Output from the keyboard is preferably developed through the use of
an elongated synthetic resin strip coated with a conductive
material such as silver or silicon conductive rubber which is
disposed transversely relative to the respective key-supporting
arms and located to be engaged by the flippers during the described
overtravel movement thereof. An elongated resistive wire is
positioned above the conductive strip, in such location that the
flipper serves to push the conductive strip into engagement with
the resistive wire for a very short "impulse" period during the
overtravel motion of the flipper. Such contact between the
conductive strip and resistive wire completes an electrical
circuit, and apparatus such as an analog/digital voltage converter
is coupled to the strip and resistive wire for determining the
magnitude of resistances developed through the wire. A
predetermined resistance corresponds to each key and associated
flipper, and in this fashion a precise determination can be made of
which of the keys has been depressed. The output from the voltage
converter is directed to utilization circuitry associated with the
overall typewriter, printer or CRT.
In fabrication procedures, a keyboard blank is molded which
includes a base member and a first set of elongated arms, with
structure pivotally coupling the first arms to the base along one
margin thereof. A key is further secured to each arm. A second set
of arms is then positioned in opposed, facing relationship to the
first arms, and the first and second arms are shifted toward one
another until the arms are generally parallel to the base, and are
pivotal about respective axes. This involves intercalating
respective arms, and captively locking each arm so that it travels
only through a predetermined key stroke arc.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a keyboard in accordance with the
invention, with parts broken away for clarity and certain parts
being illustrated in section;
FIG. 2 is a fragmentary, irregularly broken away and partially in
section front view of the keyboard depicted in FIG. 1;
FIG. 3 is a vertical sectional view taken along line 3--3 of FIG.
1;
FIG. 4 is a view similar to that of FIG. 3, but illustrating the
juxtaposition of the key-supporting arms and their underlying
flippers, and with the limits of a key stroke arc illustrated in
dotted lines on one of the keys;
FIG. 5 is a view similar to that of FIG. 4, but illustrating the
configuration of one of the keys during the initial stages of
depression thereof;
FIG. 6 is a view similar to FIG. 5, but illustrates the
configuration of a depressed key prior to release of the associated
flipper;
FIG. 7 is a view similar to that of FIG. 6, but illustrates the
configuration of a flipper during overtravel movement thereof back
to its original rest configuration;
FIG. 8 is a view similar to that of FIG. 7, but illustrates a key
having a longer arm than that of FIG. 7, with the key being in its
rest position;
FIG. 9 is a fragmentary bottom view of FIG. 5, during the initial
stages of key stroke depression and consequent flipper
engagement;
FIG. 10 is a fragmentary bottom view of FIG. 6, illustrating the
configuration of the key arm and flipper just prior to release of
the flipper;
FIG. 11 is a fragmentary bottom view of FIG. 7, depicting the
return travel of the flipper;
FIG. 12 is a somewhat schematic fragmentary view illustrating the
preferred output assembly for developing a keyboard output;
FIG. 13 is a vertical sectional view taken along line 13--13 of
FIG. 12;
FIG. 14 is a vertical sectional view taken along line 14--14 of
FIG. 12;
FIG. 15 is a vertical sectional view taken along line 15--15 of
FIG. 12;
FIG. 16 is a vertical sectional view illustrating a preferred
method of fabrication of a keyboard in accordance with the
invention, with a keyboard blank being formed in a separable
mold;
FIG. 17 is an enlarged, fragmentary vertical sectional view
illustrating formation of a key letter in one of the key tops of
the blank depicted in FIG. 16;
FIG. 18 is a top view of a completed key, shown with a letter
formed therein;
FIG. 19 is a somewhat schematic view illustrating the steps
involved in formation of a keyboard from the blank depicted in FIG.
16;
FIG. 20 is a vertical sectional view illustrating a multiple part,
separable mold used in forming a synthetic resin keyboard blank;
and
FIG. 21 is an essentially schematic view illustrating the steps
involved in formation of a completed keyboard using the blank
produced from the mold of FIG. 20.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, a keyboard 30 is depicted in FIGS. 1
and 2, and broadly includes a plurality of keys 32 arranged in
respective rows, along with an elongated, spanning, depressible
spacing bar 34. The keyboard further has means referred to by the
numeral 36 for supporting the keys 32 for individual, selective
depression thereof, and means 38 (see FIG. 12) for developing a
keyboard output related to the depression of particular keys.
Structure 40 beneath the keys 32 is employed for operably coupling
the keys and the output means 38 so that, upon depression of
particular keys, a corresponding output is developed.
In more detail, each of the keys 32 is preferably formed of
synthetic resin material and presents a slightly concave, uppermost
finger-engagement surface 42 along with a depending, circumscribing
skirt 44. The majority of the keys are essentially square in plan
configuration as best seen in FIG. 1, whereas certain of the keys
are oblong or L-shaped, as is conventional in present day
keyboards.
The key-supporting means 36 includes a substantially planar,
apertured base 46 which is rectangular in plan configuration, along
with a pair of spaced, opposed, marginal front and rear walls 48
and 50, and upright, spaced, marginal sidewalls 52, 54.
The base 46 is provided with two series 55a and 55b of apertures 56
and 58 respectively adjacent and extending along the length of
front and rear walls 48 and 50. It will be noted in this regard
that the apertures 56, 58 alternate along the length of each wall
48, 50, and that the apertures 56 are somewhat longer than the
apertures 58. In addition, it will be observed that the apertures
along the length of front wall 48 are laterally offset relative to
the apertures along the length of rear wall 50. The significance of
these features will be made clear hereinafter.
The base 46 is also provided with a series of alternating,
elongated, rectangular slots 60 and 62 therethrough which are
located between the walls 48, 50. A slot 62 is provided and is in
alignment with each aperture 56, 58 in the row 55a thereof proximal
to front wall 48; likewise, a slot 60 is provided with and is in
alignment with each aperture 56, 58 in the row 55b thereof proximal
to front wall 48.
Referring specifically to FIG. 1, it will be seen that each slot 60
is defined by a front wall 64 and a rear wall 66 along with spaced,
opposed sidewalls 68. An elongated, rearwardly extending,
resilient, deformable flipper or element 70 is secured to the front
wall 64 of each slot 60 in a cantilever fashion by means of a
short, thin connection strip 72 (see FIG. 4). The free or operating
end 74 of each element 70 is between the sidewall 68 and spaced
from the rear wall 66. Finally, a notch 76 is provided in the upper
surface of element 70 as depicted.
Each slot 62 is similar to the slots 60 and is defined by a front
wall 78, rear wall 80, and spaced, opposed sidewalls 82. An
elongated, resilient, deformable flipper or element 84 is secured
to rear wall 80 of each slot 62 and extends forwardly toward front
wall 78. Here again, the elements 84 are cantilever mounted to
their respective mounting walls by means of short connection
strips. The free or operating end 86 of each element 84 is spaced
from the front wall 78, and the upper surface of each element 84 is
notched as at 88. Notches 89 are provided in the upper face of base
46 between the slots 62 and in alignment with the element notches
76, 88, so that the notches 76, 88 and 89 cooperatively define an
elongated channel extending between sidewalls 52, 54. Finally, the
upper surfaces of the notched regions of the elements 70, 84 are
peaked as at 90 (see FIGS. 12-15).
As best seen in FIG. 1, the front walls 64 of the slots 60 are
closer to the apertures 56, 58 adjacent front wall 48, than are the
front walls 78 of the slots 62. By the same token, the rear walls
80 of the slots 62 are closer to the apertures 56, 58 proximal to
rear wall 50, than are the rear walls 66 of the slots 60. Also, it
will be seen that the respective elements 70, 84, respectively
associated with each slot 60 or 62 are cantilever mounted and
extend in opposite direction relative to one another. However, the
notches 76, 88 provided in the element 70, 84 are in alignment with
one another for purposes to be made clear.
The key-supporting means 36 further includes two sets 91 and 92 of
elongated key arms respectively pivotally coupled to the walls 48,
50. Set 91 includes alternating longer and shorter arms 94 and 96
which are oriented in laterally spaced relationship along the
length of wall 48. The longer arms 94 are located directly above
the apertures 58, whereas the shorter arms 96 are located directly
above the apertures 56. As best seen in FIG. 1, each of the arms
94, 96, extends over a portion of an associated slot 62 and element
84 therein. Referring to FIGS. 1-3, it will be seen that each of
the arms 94, 96 are pivotally connected to the upper margin of wall
48 by means of a thin, synthetic resin hinge portion 98. A
depending leg 100 extends from the end of hinge portion 98 remote
from wall 48, and has a lowermost dog 102 thereon. The dog 102 is
inserted and captively retained whithin the adjacent, associated
aperture 56 or 58 directly beneath the hinge portion 98. An
elongated arm 94, 96 extends from the leg 100 above dog 102 to a
point for supporting a key 32. To this end, the ends of the arms
94, 96 are provided with upstanding frictional connector 104 for
receiving and supporting an associated key 32.
A depending retainer 106 is secured to each arm 94, 96 and extends
downwardly therefrom and is received within the associated
underlying slot 62 in order to prevent significant lateral wiggle
of the arms and their supported keys. Specifically, the retainer
106 fits in the open portion of underlying slot 62 between the
extreme free end of the element 84 and front wall 78.
A beveled flipper-engaging member 108 is also provided with each
arm 94, 96, directly inboard of the retainer 106. The member 108
includes a substantially triangular bottom wall 110 disposed
partially above the end 86 of the element 84, an upright planar
sidewall 112, and a beveled, substantially planar sidewall 114. The
importance of this construction will be explained hereinafter.
The set of arms 92 is operatively coupled to rear wall 50 such that
the arms 116, 118 thereof are laterally spaced apart and extend
toward front wall 48. Here again, the longer arms 116 alternate
with the shorter arms 118; and the longer arms 116 are disposed
over and operatively coupled with an aperture 58 in set 55b,
whereas the shorter arms 118 are disposed over and coupled to an
underlying aperture 56.
The arms 116, 118, are coupled to their associated wall 50 in a
manner identical to that described in conjunction with the arms 94,
96 of set 91. That is to say, a hinge portion 98 and depending leg
100 having a dog 102 are provided for each arm, with the dog 102
being inserted within the associated aperture 56 or 58 for the arm.
Likewise, each of the arms 116, 118 includes a depending retainer
106 received within a slot 60 between the free end of the element
70 therein and the defining front wall 64. Finally, each of the
arms 116, 118 includes an element-engaging member 108 which is
identical to that described in connection with the arms 94, 96,
both in the structure thereof and in disposition relative to the
associated underlying elements 70.
Again referring to FIG. 1, it will be seen that the longer arms 116
support the row of keys closest to front wall 48; whereas the
shorter arms 118 support the next inboard row of keys. Thus, the
arms 94, 96 of set 91 extend in an opposed direction relative to
the arms 116, 118 of set 92. Also, the arms are intercalated so
that arms from set 91 alternate with arms from the opposing set
92.
Spacing bar 34 is supported for up and down movement thereof by
means of a pair of elongated, spaced apart arms 120 which extend
from rear wall 50 forwardly to a point just adjacent front wall 48.
The arms 120 are pivotally mounted for movement about a horizontal
axis so that the bar 34 moves in the conventional fashion.
Output means 38 (see FIG. 12) includes an elongated, resilient,
synthetic resin strip 122 having a conductive coating of conductive
rubber 124 on the upper face thereof. The strip 122 is mounted
within the channel defined by the aligned notches 76, 88 and 89. It
will thus be appreciated that the strip 122 extends above and
transversely relative to the longitudinal axes of the respective
elements 70, 84, and below the arms 94, 96 and 116, 118.
The output means 38 further includes an elongated, resistive wire
126 preferably formed of so-called "Nichrome" material. The wire
126 is located slightly above and extends along the length of the
strip 122. A plurality of spaced apart tubular insulators 128 are
provided on wire 126 and respectively straddle the underlying
elements 70, 84. An analog/digital voltage converter 130 provided
with a suitable reference voltage source (not shown) is operatively
coupled to the wire 126 and conductive coating 124 such that, when
one of the elements 70, 84 moves in a manner to engage a zone on
the strip 122 and push the latter into momentary impulse contact
with wire 126, a characteristic resistance corresponding to the
element (and thereby the associated key) is developed and sensed.
An output cable 132 is coupled to appropriate utilization circuitry
(not shown) forming a part of the overall typewriter or
printer.
Referring again to FIG. 1, it will be seen that the arms 94 support
keys 32 in the row thereof furthest from wall 48. By the same
token, the shorter arms 96 support the keys forming the second row
thereof spaced from rear wall 50.
The operation of keyboard 30 can best be understood from a
consideration of FIGS. 4-11. In the ensuing discussion, the
operation of keyboard 30 during depression of a particular key 32a
supported by one of the arms 118 will be described; it will be
understood, however, that the operation of the remaining keys is
identical in all material respects.
At the outset (see FIG. 4) it will be appreciated that, in the rest
position of key 32a, the arm 118 extends generally horizontally
relative to the base 46, and is pivotally movable by virtue of the
associated hinge portion 98. In addition, the dog 102 is disposed
within the underlying aperture 56 adjacent rear wall 50. The
orientation of dog 102 within the aperture 56 thus limits the
extent of pivotal movement of the arm 118. The limits of this
pivotal movement are illustrated in FIG. 4 by means of respective
sector lines 134 and 136 which define the predetermined arc of
travel of the arm 118 and, consequently, the key 32a. In addition,
it will be seen that the pivot axis for arm 118 is elevated above
the longitudinal axis of the arm, and lies in a horizontal plane
(depicted by line 138 in FIG. 4) which intersects the predetermined
arc of travel of the key. It has been found that the described
orientation of the pivot axis for the respective arms give a "feel"
to the user which closely simulates conventional typewriter
keyboards.
In any event, upon initial depression of the key 32a (see FIGS. 5
and 9), the engagement surface 110 on the member 108 comes into
contact with the upper surface of free end 74 for the underlying
element 70. Continued downward movement of the key under the
influence of finger pressure serves to deform and deflect the end
74 of the element 70 (see FIGS. 6 and 10) downwardly, with the
effect that the potential energy of the resilient element is
increased, along with its resistance to further deflection.
By virtue of the pivoting action of the element-engaging member 108
and the surface 110 thereof, a point is reached where the surface
110 passes out of engagement with end 74 of element 70. This can
best be understood from a consideration of FIGS. 9-11, wherein a
line 140 has been applied with corresponds to the innermost extent
of the number 108 prior to depression of the key 32a. As such
depression proceeds, the surface 110 pivots away from the end 74 of
the element 70 until, as seen in FIG. 11, the element 70 is
completely disengaged from the surface 110.
When such disengagement occurs, the deformed and deflected element
70, because of the resilient nature thereof, springs back upwardly
at a very high rate of speed toward its rest position (see FIGS. 7
and 11).
During such return movement of the element 70, the element
overtravels the original starting or rest position thereof, and,
during such overtravel, engages with a momentary impact the
underside of the strip 122. As best seen in FIGS. 12 and 15, the
overtravel movement serves to push or propel the strip upwardly
till the conductive coating 124 thereon comes into a momentary
pulse-type engagement with the resistive wire 126. Such impulse
movement is facilitated by virtue of the peaked nature of the
element at the region of the notch 76 therein, which is indicated
by the reference numeral 90. In effect, the peaked sections, in
conjunction with the conductive rubber coated strip 122, cause an
arcuate portion of the strip to orthogonally contact the circular
in cross section wire 126; such cross point contact creates a
relatively high mechanical stress region at the contact point which
is desirable to establish a firm, yet momentary contact pressure
between the components. Further, it will be observed that contact
between the strip 122 and wire 126 at multiple points is prevented
by virtue of the straddling insulators 128 respectively disposed on
opposite sides of the element 70.
When the zone of strip 122 directly above the element 70 is caused
to engage wire 126, a circuit coupled with the converter 130 is
established from the converter 130 through the portions of the
coating 124 and wire 126 electrically between the converter and the
contact point. The converter 130 senses the magnitude of the
electrical resistance developed in the involved portion of the wire
126 during such circuit closing, and delivers a suitably
corresponding electrical output (e.g., a binary encoded character
code) to the cable 132. It will be appreciated in this regard that
the element 70, when it closes the electrical circuit as described,
presents to the converter 130 a unique, predetermined resistance
magnitude corresponding to the key 32a so that the converter 130
will provide an appropriate distinctive output signal corresponding
to the key 32a. By the same token, each of the remaining elements
70, 84, and their associated keys, have a unique resistance
magnitude respectively associated therewith, so that the device 130
can output a proper distinctive signal in each case.
Referring now to FIGS. 16-19, a preferred method of fabrication of
a keyboard in accordance with the invention is illustrated. In FIG.
16, a mold 142 is illustrated having a base section 144, an upper
section 146, and a pair of separate comb-like elements 147. The
mold 142 is employed to form a blank 148 used in the fabrication of
a completed keyboard 30. The blank 148 includes a base 46 having
respective sets 55a and 55b of apertures 56, 58 along spaced
margins thereof, along with front and rear walls 48, 50 secured to
the base margin along respective lines of weakness 150, 152. Each
aperture 56, 58, includes a flexible section 153 at the inner face
thereof permitting insertion of a corresponding dog 102 in the
final fabrication process. In addition, the base 46 is molded to
include all of the other described structure, e.g., the slots 60,
62 and flipper elements 70, 84. The arm sets 91, 92 are
respectively secured to the margins of the walls 48, 50 remote from
the base 46, and these arms are configured as described above. In
addition, a pair of elongated spacer bar-supporting arms 120 are
provided for the bar 34.
Respective keys 154 are integrally attached to the outermost end of
each of the described arms. As best seen in FIGS. 16 and 17, the
arms are secured to their associated keys 154 along one margin of
the skirt thereof. A removable die block 156 is inserted through
the upper mold section 146 and into each separate key 154. The die
blocks 156 have, on their innermost ends, structure for forming
informational indicia openings in the keytops. A separate filler
block 157 extends through the section 146 and into spacer bar 34 as
shown. Thus, during the molding process, letters or other
appropriate indicia are formed in the upper surfaces of the keys by
virtue of the presence of the die blocks.
It will be understood that a blank 148 can be fabricated using mold
142 and conventional injection molding techniques. When the initial
injection is completed, the die blocks 156 are removed from their
associated opening and keys, and a filler material 158 (see FIG.
17) of a different colored synthetic resin than that forming the
main body of the blank is placed within each key body. A secondary
block 160 is placed within the associated openings in section 146
and the keys 154, in order to press the material 158 into the
indicia openings left by the die blocks 156. This serves to fill
such openings and give a completed key top bearing the appropriate
indicia thereon. FIG. 18 illustrates a completed key bearing the
letter "A".
In fabrication procedures, the blank 148 is placed on a work
surface, and the walls 48, 50 turned upwardly relative to the base
along the lines of weakness 150, 152 (see FIG. 19). The next step
involves pivoting the respective arms of each set 91, 92 thereof
downwardly until such arms are generally horizontal and parallel
with base 46. At this point, the dog 102 associated with each arm
is inserted within the underlying base aperture 56 or 58 (such
being facilitated by the presence of the flexible sections 153), so
that the arm is captively held for pivotal movement along a
predetermined arc, as hereinabove explained. During such movement
of the arms, they are intercalated as explained, and are oriented
over the corresponding elements formed in the base 46. The final
steps in the fabrication process involve shifting the arms 120
downwardly and interconnecting the same with the transversely
extending spacer bar 34. The output means 38 can then be installed
in the blank 148 in order to give a completed keyboard.
FIGS. 20-21 illustrate a similar molding process for the production
of a two-part blank 162. In this instance the mold 164 includes a
pair of side-by-side interfitted base sections 166, 167, 168, along
with a pair of upper sections 170, 172. A pair of elongated
comb-like elements 173 are also provided, along with respective
elongated inserts 173a. The blank 162 is molded to present a base
46 having a sidewall portion 48 secured thereto along a line of
weakness 174. One set of arms 91 are secured to the end of wall 48
remote from base 46. The latter includes the aperture sets 55a and
55b, as well as the other described structure of the base including
the slots, elements and flexible sections 153. The second set of
arms 92 is also formed within mold 164 as a separate element
between the upper portion of base section 168 and the lefthand face
of upper base sections 172. The arm set 92 includes the sidewall 50
secured thereto, and the sidewall 50 and the margin of base 46
remote from wall 48 are provided with appropriate connectors 176,
178. The arm set 92 includes the elongated arms 120 and spacer bar
34. It will be seen that the apparatus of FIG. 20 serves to mold
the respective arm sets 91, 92 in an intercalated condition so that
upon final fabrication this procedural step is eliminated.
The keys 154 are formed simultaneously with the respective arms of
each set 91, 92, as in the case of the embodiment of FIGS. 16-19.
Here again, die blocks 180 bearing the appropriate key indicia, and
filler block 181, are initially positioned within the mold sections
168, 170 as illustrated, so that the keys, when formed, include the
appropriate indicia openings in the upper surfaces thereof. The
respective keys 154 are completed as illustrated and described in
connection with FIGS. 17-18, i.e., use of a material 158 having a
different color than that of the main body of the keys 154.
The fabrication technique involves connecting the wall 50 to the
margin of base 46 remote from wall 48, through use of the
connectors 176, 178. The final step involves pivoting of the
respective arm of the sets 91, 92 until such arms (which are
already intercalated) are oriented as hereinabove described.
Although the keyboards in accordance with the invention have been
particularly described as including various specific construction
features, it will be appreciated that the invention is not so
limited. To give but one example, a wide variety of devices can be
employed for sensing movement of the resilient elements, and for in
turn developing a keyboard output. Various known techniques
utilizing electromagnetic radiation such as optical sensors can be
employed in this context.
Furthermore, although in preferred forms the keyboards are
described as being formed from synthetic resin materials, those
skilled in the art will readily appreciate that other materials can
be substituted. However, synthetic resins are preferred because of
their low cost and ease of molding.
* * * * *