U.S. patent number 3,881,106 [Application Number 05/438,288] was granted by the patent office on 1975-04-29 for device for producing electrical signals by means of a control stick.
This patent grant is currently assigned to Messerschmitt-Blokow-Blohm GmbH. Invention is credited to Gert Grundmann, Erwin Pocker.
United States Patent |
3,881,106 |
Pocker , et al. |
April 29, 1975 |
Device for producing electrical signals by means of a control
stick
Abstract
A device for producing electrical signals, comprises a control
stick which is pivotally mounted for back and forward movement
intermediate its length. One end of the control stick, for example
the bottom end, is provided with a source of luminous radiation
adjacent this end, and the stick is biased into a neutral position,
for example a central position, by means of spring elements
engaging it from respective opposite sides. The apparatus includes
at least four fixed photosensitive cells which are disposed
symmetrically about the radiation source. Two of each of the
photosensitive cells are connected to each of two circuits of an
electrical transmission means which comprises two electrical
circuits. The source of radiation is advantageously surrounded by a
screen which is secured to the control stick for movement
therewith. Preferably, two photosensitive cells are disposed at
mutually opposed locations and connected in a common circuit with
the cells disposed in one plane and the cells disposed in the
opposite plane being mounted in opposition to each other.
Inventors: |
Pocker; Erwin (Feldolling,
DT), Grundmann; Gert (Westerham, DT) |
Assignee: |
Messerschmitt-Blokow-Blohm GmbH
(Munich, DT)
|
Family
ID: |
5873214 |
Appl.
No.: |
05/438,288 |
Filed: |
January 31, 1974 |
Foreign Application Priority Data
|
|
|
|
|
Feb 27, 1973 [DT] |
|
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2309682 |
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Current U.S.
Class: |
250/234; 250/221;
250/239; 250/214PR |
Current CPC
Class: |
G05G
9/047 (20130101); G05G 5/05 (20130101); G05G
2009/04707 (20130101); G05G 2009/04759 (20130101) |
Current International
Class: |
G05G
9/047 (20060101); G05G 9/00 (20060101); H01j
007/24 () |
Field of
Search: |
;250/230,231,234,235,239
;356/250 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Stolwein; Walter
Attorney, Agent or Firm: McGlew and Tuttle
Claims
What is claimed is:
1. A device for producing signals, comprising a control stick
having a manipulatable handle portion and being universally
pivotally movable to transmit control signals, universal mounting
means mounting said control stick for universal pivotal movement,
biasing means urging said control stick into a neutral position,
transmission means comprising two electrical circuits adapted to be
influenced by the angular position of said control stick, a source
of luminous radiation mounted on and adjacent an end of said
control stick at a spaced location from its pivotal mounting, means
associated with said luminous radiation source to shield the
photocells from the source in predetermined positions of said
control stick, and at least four fixed photosensitive cells
arranged in opposed pairs disposed symmetrically about said
radiation source and two being connected in each of said two
circuits, the center lines of said cells each being in a plane
containing the axis of said control stick in said neutral position
and being disposed at an angle to each other which is less than
180.degree..
2. A device for producing signals, according to claim 1, wherein
said shielding means comprises a screen surrounding said source of
radiation and carried by said control stick and in which said
photosensitive cells have bottom edges which extend in the same
plane as the bottom edge of said screen.
3. A device for producing signals, according to claim 1, wherein
said photosensitive cells are directly exposed to the said source
of radiation.
4. A device for producing signals, according to claim 1, wherein
said electrical circuits include a circuit having two
photosensitive cells disposed at mutually opposed locations and
being disposed in a plane which is perpendicular to the plane of
the other two of said cells.
5. A device for producing signals, according to claim 1, wherein
said photosensitive cells are passive cells.
6. A device for producing signals, according to claim 1, wherein
said photosensitive cells are active cells.
7. A device for producing signals, according to claim 1, wherein
said control stick is a double-armed lever, including an upper
portion which is adapted to be engaged by a person's hand and a
lower portion on the opposite side of said pivotal mounting
carrying said source of luminous radiation.
8. A device for producing signals, according to claim 7, wherein
said source of luminous radiation is carried on the outer end of
the bottom of said control stick.
9. A device for producing signals, according to claim 1, wherein
said control stick comprises a single arm lever, said luminous
source of radiation being spaced from said pivotal connection
upwardly along said control stick.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates in general to the construction of control
devices and, in particular, to a new and useful device for
producing electrical signals by means of a control stick.
2. DESCRIPTION OF THE PRIOR ART
Control devices are known which include a pivotal control stick for
effecting the transmission of control signals. With the known type
of devices, the control signals produced by varying the inclination
of the control stick are used for controlling the movement and
position of hoisting units and machine tools or for the remote
control of aircraft surfaces, for example. Control and steering
operations of this kind require a sensitive actuation, if possible,
with a complete elimination of inertial forces and an immediate
response of the system to any change in the position of the control
stick.
In a known remote control device for automatically moving bodies, a
tilting of the control stick provided results in the adjustment of
two potentiometers which are disposed in two control planes
perpendicular to teach other. The control voltages, which are
transformed into remote control signals corresponding to the
control planes, are a function of the control stick position and
are tapped off of the potentiometers.
Such a device has several drawbacks. From the mechanical point of
view, there must be provided a certain minimum size if a
statisfactory precision is to be obtained. Limits are therefore set
in respect to miniaturization of such a system. Further,
potentiometers permit voltage variations only in steps. They also
have the disadvantage that a permanent use leads to abrasion and
consequently corrosion of the sliders and turns, reducing the life
of these parts and increasing the contact resistances with the
necessiity of frequent adjustment as a reslt.
SUMMARY OF THE INVENTION
The present invention provides an easily operable control stick
unit of small size wherein voltages, approximately proportional to
the angular position of the control stick, are delivered as control
signals to a control device connected thereto and, during the
operation, the mechanical wear of the parts is maintained at a
minimum. In accordance with the invention, this problem is solved
by providing a source of luminous radiation mounted on one end of a
pivotal control stick, and at least four fixed photosensitive cells
which are disposed symmetrically about the source of radiation,
with two each of said cells being connected in each one of two
separate electrical tranmission circuits.
In one embodiment of the invention, the source of radiation is
surrounded by a screen which is secured to the control stick and
the photosensitive cells are disposed so that, in the neutral mid
position of the control stick, they extend parallel to the axis of
the stick and their bottom edges are flush with the bottom edge of
the screen.
In another embodiment of the invention, the screen is omitted and
the photosensitive cells are directly exposed to the source of
radiation and located in planes forming an angle with the axis of
the control stick in mid position.
The invention further provides a circuit arrangement for the
electrical part of the control stick unit in which two of the
photosensitive cells are opposed to two others, and each two are
connected in a common circuit and mounted electrically in
opposition to each other.
The invention has many advantages with respect to the prior art. In
the first place, the simple construction of the control stick,
which requires no intermediate mechanical parts for producing the
variable control voltages, permits a simple adaptation to the
desired value of the control voltage. Thus, for special purposes,
it is possible to provide a miniaturization of the parts in a solid
state construction which has not been feasible with the known
control stick units heretofore. Because the control stick is the
single mobile part in the device and the source of radiation
mounted thereon can be operated with undervoltage, the unit
requires substantially no maintenance. The actuation of the control
stick is not hindered by any mechanical transmission member so that
the ease of manipulation can be adjusted at any time to the desired
degree by adjusting the springs retaining the stick in the neutral
mid position. The photosensitive cells may be selected in
accordance with the problem to be solved. At voltages of about 3 to
4 v and more, it is preferable to use photo-emissive cells. These
cells are connected into the circuit with the working voltage
applied thereto and are conductive only when irradiated. Their
conductivity attains a certain saturation at which the full applied
voltage can pass through and may be collected.
It is also possible, however, to use photoconductive cells
producing the voltage themselves so that only the current for the
source of radiation is to be supplied from a small battery. The
desired voltage value may also be predetermined by choosing not
only the type but also the quantity of the photocells disposed in
each plane. Another advantage is the fact that the voltage
variation as a function of the stick inclination can be influenced
by selecting an appropriate source of radiation. For example, with
a luminous source having the lamp bulb flattened on the front end,
a more flattened voltage rise will be obtained at small angles than
at large angles of inclination of the stick, which is desired for
some purposes. Possible variations in the brightness of the
luminous source can be made ineffective by adjusting the saturation
limit of the photosensitive cell to the smallest brightness range.
Thereby, a completely uniform collection of light and,
consequently, delivery of voltage is obtained irrespective of the
direction in which the stick has been tilted.
Accordingly, it is an object of the invention to provide a device
for producing signals which includes a control stick which is
pivotally mounted intermediate its length and which may be pivoted
to effect the transmission of control signals through a
transmission means which includes two electrical circuits, the
stick being biased into a netural position and being provided with
a source of luminous radiation on an end which is spaced from the
pivotal mounting thereof which is surrounded by at least four
symmetrically arranged photosensitive cells with two of each of
these cells being connected in respective ones of the two
circuits.
A further object of the invention is to provide a device for
producing signals which is simple in design, rugged in construction
and economical to manufacture.
For an understanding of the principles of the invention, reference
is made to the following description of typical embodiments thereof
as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the Drawings:
FIG. 1 is a transverse sectional view through a control device
constructed in accordance with the invention;
FIG. 2 is a view of the control device of FIG. 1 shown in an
operative position;
FIG. 3 is a view similar to FIG. 1 of another embodiment of the
invention;
FIG. 4 is a circuit diagram for one tilting plane of the control
stick; and
FIG. 5 is a view similar to FIG. 1 of another embodiment of the
invention.
GENERAL DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings in particular, the invention embodied
therein in FIG. 1, comprises a control device, generally designated
50, which, for example, may comprise a control mechanism for
operating the surfaces of an aircraft and which includes a control
stick 1 in the form of a double armed lever which is pivotally
mounted in a pivot bearing or gimbal mounting 2 on a top wall of a
container or frame 3. The bearing 2 is advantageously a universal
bearing and permits the control stick 1 to be tilted by an angle
.alpha. in all of the planes which pass through the axis of the
control stick 1. The control stick is held in a neutral position,
in this case a central position, by four separate springs 4, which
are connected intermediate the length of a top arm portion 1a of
lever 1 and frame 3 at four locations which are spaced on frame 3
at 90.degree. from each other. Springs 4 constitute biasing means
for biasing stick 1 into a netural position.
In accordance with the invention, the control stick 1 also includes
another end portion or bottom end portion 1b which carries a
luminous source 5 at a spaced location from the pivotal mounting 2,
for example, at the bottom end. Luminous source 5 is supplied with
electric current by a connection extending through the stick, which
has not been shown. At least four separate photosensitive cells 7a
to 7d are arranged at equally spaced locations from the luminous
source in a fixed position inside of the frame 3 with their bottom
edges flush with the bottom edge of a screen 6 which is positioned
around the lower end of control stick 1. Photosensitive cell 7d,
which is opposite to cell 7c, shown in FIG. 2 is not indicated. In
the embodiment shown, at least four photosensitive cells 7 are
provided, but a number more than 4, for example 8, 12 or even more,
may be used for producing higher voltages.
The embodiment shown in FIG. 3 comprises a control device,
generally designated 52, which includes a control stick or double
armed lever 1', which is pivotally mounted on a universal joint 2'
and is biased into a neutral position by springs 4', similar to the
embodiment shown in FIG. 1. In the construction shown in FIG. 3,
the luminous source comprises a lamp 10, which is located on the
arm portion 1b' of control stick or double armed lever 1'. Lamp 10
comprises a rounded glass bulb which irradiates the photosensitive
cells 7a', 7b', 7c' and 7d', but without a screen interposed
therebetween. Cells 7 are mounted so as to be inclined with respect
to the axis of the control stick in the neutral position.
FIG. 4 shows a circuit diagram arrangement which includes a
possible series connection of the photosensitive cells 7a and 7b
which, for example, may also be photo-emissive cells and thus
connected in a circuit to which a working voltage is applied.
Positive voltage is applied to terminal 20 and a negative voltage
is applied to terminal 21. Balancing resistances 22 and 23 are
provided between the photo-emissive cells 7a and 7b, permitting a
precise fixing or shifting of the starting point of the voltage
increase. Between the balancing resistances 22 and 23, a load
resistance 24 is connected in parallel to the two cells 7a and 7b.
The signal voltage for a control device (not shown) is collected
between terminals 25 and 26 which are located at the two ends of
the load resistance 24. Outside of terminal 25, the circuit is
closed through a ground terminal 27.
In the circuit arrangement shown in FIG. 4, the photosensitive
cells function in a passive manner, that is they are non-conducting
as long as they are not irradiated by a luminous source. Their
conductivity rises linearly with the incident luminous radiation up
to a maximum value. The maximum value of current flow should
substantially correspond to the applied voltage which can then be
collected at the terminals 25 and 26. If active, that is
photoconductive or photovoltaic cells are used, terminals 20 and 21
are connected to ground terminal 27. In such a case, the voltage is
produced in the cells themselves, and can also be collected at
terminals 25 and 26 up to a maximum value depending on the type of
end quantity of the cells used.
The control stick unit operates as follows:
In the vertical, that is, the neutral position of control stick 1,
photosensitive cells 7 are not irradiated, as shown in FIG. 1,
because of intervening screen 6. With the tilting of control stick
1 by an angle .alpha., photosensitive cell 7a is irradiated by the
light in a degree determined as a function of the angle, and it
becomes correspondingly conductive for the current flowing from
terminal 20 until it is in the limit position of the stick, as
shown in FIG. 2. The full applied positive voltage can be collected
between terminals 25 and 26.
While tilting control stick 1 by an angle .alpha. in the opposite
direction, negative current flows from terminal 21 through
photosensitive cell 7b and can be collected between terminals 25
and 26 as a negative voltage. The same is obtained with
photosensitive cells 7c and 7d if control stick 1 is tilted
perpendicularly to the drawing plane and a positive or negative
voltage can be collected in the respective circuit, which is
arranged in the same manner as shown in FIG. 4.
Control stick 1, mounted in a ball-socket swivel-bearing, can be
tilted in any direction, and the voltage produced corresponds to
the angular position and directional orientation of the stick. In
the example of FIG. 3, in the neutral position of control stick 1',
the currents flowing through the two branches of the circuit and
resulting from the irradiation of the photosensitive cells,
compensate each other. At the tilting of stick 1', a difference
voltage is obtained corresponding to the angular position and
orientation and resulting from the voltages produced in the
respective photosensitive cells 7a' to 7d'. In the same manner as
described in connection with FIGS. 1 and 2, this difference voltage
can be collected at terminals 25 and 26. The embodiment of FIG. 3
has the advantage of better utilizing the radiation.
It is evident that instead of being a two-armed lever, as provided
in the examples shown, the control stick 1, 1' may also be designed
as a one-armed lever, such as the control stick 3 shown in FIG.
5.
The control stick 3 is universally mounted on a universal mounting
2" as shown in FIG. 5, and it includes a luminous source 5", which
is located near its bottom end at a spaced location from pivot 2".
Photoelectric cells 7a", 7b", 7c" and 7d"are arranged symmetrically
around luminous source 5", as in the other embodiments.
While specific embodiments of the invention have been shown and
described in detail to illustrate the application of the principles
of the invention, it will be understood that the invention may be
embodied otherwise without departing from such principles.
* * * * *