U.S. patent number 3,648,143 [Application Number 04/852,538] was granted by the patent office on 1972-03-07 for automatic work-repeating mechanism.
This patent grant is currently assigned to Harper Associates, Inc.. Invention is credited to Kenneth B. Harper, Hubert J. Tremblay.
United States Patent |
3,648,143 |
Harper , et al. |
March 7, 1972 |
AUTOMATIC WORK-REPEATING MECHANISM
Abstract
An electric motor-controlled device having elements
corresponding to human appendages, the elements being manually
movable to perform a function recorded on tape, the elements
thereafter repeating the function in response to repeated playbacks
of the tape.
Inventors: |
Harper; Kenneth B. (Winnetka,
IL), Tremblay; Hubert J. (Roselle, IL) |
Assignee: |
Harper Associates, Inc.
(Winnetka, IL)
|
Family
ID: |
25313579 |
Appl.
No.: |
04/852,538 |
Filed: |
August 25, 1969 |
Current U.S.
Class: |
318/568.1;
318/162; 414/4; 901/4; 901/20; 901/23; 901/25 |
Current CPC
Class: |
B25J
9/0081 (20130101); G05B 19/42 (20130101); G05B
2219/40305 (20130101) |
Current International
Class: |
B25J
9/00 (20060101); G05B 19/42 (20060101); G05b
019/42 () |
Field of
Search: |
;318/162,568 ;214/1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dobeck; Benjamin
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A work-repeating mechanism including a base, a work-performing
arm movably mounted on said base, an electrical motor having a
driving control connection with said arm, means for generating
signals in response to manual movement of said arm, recording means
for recording said signals and playback means for transmitting said
signals from said recording means to said motor to cause movement
of said arm corresponding to said manual movement.
2. The structure of claim 1 characterized by and including
electrical means for activating said motor in response to the
manual movement of said arm.
3. The structure of claim 2 wherein said electrical means comprises
a gear on said arm, a permanently grounded gear on said motor, a
circuit including said arm gear and said motor, said circuit being
activated in response to contact of said gears, said gears forming
said driving connection.
4. The structure of claim 3 wherein said arm gear has a dual set of
teeth offset from each other and said motor gear has conformations
formed and adapted for engagement with one or the other of said
sets of teeth or with neither.
5. The structure of claim 1 wherein said arm includes an upper arm
segment, a forearm segment, and at least one finger segment and
characterized by and including an electrical motor and driving
connection for each of said segments.
6. The structure of claim 1 characterized by and including a homing
member adjustably carried on said base, a conducting surface on
said member, a nonconducting surface on said member and a wiper
positioned on said arm and in contact with one of said member
surfaces at all positions of said member.
7. The structure of claim 6 characterized by and including an
electrical circuit including said member and said motor, said
circuit being activated in response to contact of said wiper with
said conducting surface, said circuit being deactivated in response
to contact of said wiper with said nonconducting surface.
8. The structure of claim 1 wherein said motor has a dual set of
brushes and said playback means includes a playback head, an
amplifier receiving said signals from said head, a stepper
receiving said signals from said amplifier and thereupon delivering
first signal pulses to one set of brushes in said motor to drive
it, said stepper substantially simultaneously delivering second
signal pulses to another set of brushes in said motor to control
the direction of rotation thereof.
9. The structure of claim 1 wherein said motor has a first and
second set of brushes and said playback means includes a playback
head, a first amplifier receiving said signals from said head, a
phase detector receiving said signals from said first amplifier, a
frequency multiplier receiving signals from said first set of motor
brushes, a second amplifier receiving said last-named signals from
said frequency multiplier, said phase detector receiving said
last-named signals from said second amplifier, said phase detector
determining the relationship of said signals and delivering its
output to said second set of motor brushes to drive said motor.
10. The structure of claim 1 wherein said motor has a first and
second set of brushes, said driving connection includes a gear
driven by said motor and a second gear mounted on said arm and said
recording means includes means for recording the direction speed
and duration of motion of said motor in response to manual
manipulation of said arm, said recording means including a circuit
including said second gear and said motor, a source of positive and
negative voltage, a set of relays in contact with said second gear
for alternate activation in response to rotation of said arm gear
in clockwise or counterclockwise direction, said relays placing
said voltage source in circuit with said first brushes to drive
said motor, a frequency multiplier in said circuit and receiving an
output signal from said second brushes, an amplifier receiving said
signal from said frequency multiplier and delivering said
last-named signal to a recording head for recording the same.
11. The structure of claim 1 wherein said driving connection
includes a first gear driven by said motor and a second gear
mounted on said arm for driving engagement with said first gear and
said recording means includes means for recording the motion of
said second gear, said last-named means including a circuit
including said second gear, an oscillator, an amplifier and a
recording head, said first gear being permanently grounded, said
second gear having a first set of teeth engaging said first gear
when said arm is moved in one direction and a second set of teeth
engaging said first gear when said arm is moved in a second
direction, contact of said teeth with said motor gear being
effective to activate said circuit.
12. The structure of claim 1 characterized by and including fluid
power means engaging said arm and an electrically operable value
means directing operation of said fluid power means to urge said
arm in the direction imparted to said arm by said motor, said
playback means including means delivering electrical energy to said
valve means.
13. The structure of claim 5 wherein said recording means includes
a cassette cartridge and a tape record therein, said tape record
having a width sufficient for recording thereon of an individual
track for each of said motors and driving connections.
14. A mechanism including a base, a manually movable arm on said
base, an electric motor, a driving connection between said motor
and said arm, a record and an electrical circuit for recording
signals on said record in response to movement of said driving
connection and motor and for delivering said signals to said motor
to operate it in response to playback of said record, said circuit
including an oscillator, a first amplifier, a first sensor sensing
the input to said first amplifier, said motor, a second amplifier,
a second sensor sensing the signal input to said second amplifier,
a slow-speed motor control circuit, a phase comparator, a source of
voltage, relays operable in response to grounding of said driving
connection and operable to connect said voltage source to said
motor, said oscillator being responsive to grounding of said
driving connection to deliver signals to said first amplifier, said
first amplifier delivering said last-named signals to said record,
said second amplifier receiving signals from said record and
delivering said last-named signals to said comparator, and a
multiplier receiving signals from said motor and delivering said
last named signals through said first amplifier to said comparator,
said comparator delivering its output to said motor to operate
it.
15. The structure of claim 14 wherein said circuit includes a
high-low relay and a series of switches controlled thereby, said
relay being responsive to said sensors.
16. The structure of claim 14 characterized by and including a
rewind relay, said relay being operable in response to a signal
received from said tape to rewind the same.
17. The structure of claim 14 characterized by and including a
homing circuit including at least two conducting surfaces
adjustable on said base, a nonconducting surface adjacent said
conducting surfaces and adjustable therewith, a wiper on said arm
and engageable with said surfaces, said surfaces being connectable
with said oscillator in response to activation of said rewind
relay, said oscillator in response to contact of said wiper with
one of said conducting surfaces delivering a signal to said first
amplifier, said first amplifier delivering said last-named signal
through said slow-speed control to said motor to operate it and to
move said arm and wiper toward said nonconducting surface.
18. The structure of claim 14 wherein said motor has a first set
and a second set of brushes and said slow-speed control is
connected to said brushes for delivery of pulse signals
simultaneously to said first and second set of brushes.
19. The method of recording on a record the manual movement of a
movable member which includes the steps of providing an electric
motor and a driving control connection between said motor and said
member, said connection having a grounded part and a part movable
into contact with said grounded part in response to movement of
said member which includes the steps of manually moving said member
to bring said last-named part into contact with said grounded part
to cause grounding of said driving connection and production of a
signal in an oscillator, amplifying said signal, transmitting said
signal to a recording head and transferring said signal from said
recording head to said record.
20. The method of claim 19 characterized by and including the steps
of continuing to manually move said member, electrically activating
said motor in response to said continued manual movement of said
member to produce a signal from said motor, amplifying said signal,
transmitting said signal to a recording head and transferring said
signal from said recording head to said motor.
21. A work-repeating mechanism including a support, an arm movably
mounted on said support, an electric motor, a worm driven by said
electric motor, a gear carried on and movable with said arm, said
gear having teeth interpenetrating with said worm, said worm being
permanently grounded, an electrical circuit including said electric
motor, said gear and a recording means, said gear being movable
into contact with said worm in response to manual movement of said
arm to ground said circuit and to activate said electric motor for
rotation of said worm and to permit further movement of said gear,
said circuit and recording means being effective to record the
movement of said motor in response to said activation.
22. The structure of claim 21 characterized by and including motor
means connected to said arm, a playback circuit including said
electrical motor and said motor means, said motor means being
activated by said circuit to continuously urge said arm in one of
two directions, said electric motor being activated by said circuit
to rotate said worm to permit said movement of said arm by said
motor means.
Description
SUMMARY OF THE INVENTION
The invention includes a support having electric motor-controlled
elements thereon. The elements correspond to human appendages such
as arms and fingers. A recording tape and electrical circuitry
records the actions of the electric motors when the elements are
manually moved to perform a piece of work or function. In response
to playback of the tape, the elements will repeat the movements. A
gear switch assembly and circuit enables motor operation to assist
during manual element manipulation. An adjustable bezel ring and
circuit ensures return of the elements to a home base position. A
low-speed control stepper operates the motor at low speed in
half-revolutions and directs a biasing signal to insure motor
direction. A phase detector ensures accurate matching of motor
speed to tape signals. An oscillator and rewind circuit provide
homing and rewind signals and low-speed program recording. Fluid
power means assist element movement. The motor of the invention is
a small DC motor of particular construction and having a commutator
shaft and slipring structure.
This invention relates to automatic work-repeating mechanisms and
has as one of its purposes the provision of such a mechanism of
maximum simplicity and minimum cost.
Another purpose is to provide an automatic mechanism which may be
taught or programmed to perform a wide variety of functions.
Another purpose is to provide an automatic mechanism which may be
taught by manual manipulation.
Another purpose is to provide an automatic work mechanism which may
be retaught to perform a changed function without modification of
the mechanism itself.
Another purpose is to provide a teachable mechanism having
electrical means for assisting in the teaching operation.
Another purpose is to provide an electrical motor of minimum
complexity, size and weight.
Another purpose is to provide such a motor energized by DC current
and generating AC current.
Another purpose is to provide an actuating assembly in which a
fluid power means rotates a gear and an electric motor rotates a
worm to permit said gear rotation.
Another purpose is to provide an electrical circuit capable of
recording motor-generated signals on tape.
Another purpose is to provide a circuit capable of high and low
speed motor operation, recording signals on tape and operating said
motor in response to such signals.
Another purpose is to provide an electrical phase detector
circuit.
Another purpose is to provide a control circuit having
automatically alternating high and low speed characteristics.
Another purpose is to provide an electrical motor and circuit
effective to change the direction of movement of the motor.
Another purpose is to provide a tape-controlled assembly having
automatic rewind capability.
Another purpose is to provide a method of operating a motor.
Another purpose is to provide a driving gear connection having
electrical transmission characteristics.
Another purpose is to provide a method of recording and reproducing
movement of a mechanism.
Another purpose is to provide an electrical motor and circuit and
means biasing the motor.
Another purpose is to provide bezel and circuit means insuring
return of elements to a predetermined position.
Another purpose is to provide an electrical motor having commutator
and slipring elements, each with associated brushes.
Other purposes will appear from time to time during the course of
the specification and claims.
BRIEF DESCRIPTION OF THE DISCLOSURE
The invention is illustrated more or less diagrammatically in the
accompanying drawings wherein:
FIG. 1 is a side elevation;
FIG. 2 is a side elevation of a motor of the invention;
FIG. 3 is a view similar to that of FIG. 2 with parts removed and
parts broken away;
FIG. 4 is a detail view showing a gear train for the motor of FIGS.
2 and 3;
FIG. 5 is an end view of the motor of FIG. 2;
FIG. 6 is a detail view on an enlarged scale of an armature disc of
the motor of FIG. 2;
FIG. 7 is a detail view on an enlarged scale of a brush-holding
closure for the motor of FIG. 2;
FIG. 8 is a detail end view on an enlarged scale, with parts in
cross section of a commutator shaft for the motor of FIG. 2;
FIG. 9 is a view taken on the line 9--9 of FIG 8;
FIG. 10 is a side view on an enlarged scale of an articulation area
of the structure of FIG. 1;
FIG. 11 is a top plan view of the structure of FIG. 10;
FIG. 12 is a partial exploded view of a drive connection of the
structure of FIG. 1;
FIGS. 13, 14 and 15 are detail views illustrating elements of FIG.
12 in various positional relationships;
FIG. 16 is a view taken on the line 16--16 of FIG. 12;
FIG. 17 is a detail view of a bezel element shown in FIG. 11;
FIG. 18 is a perspective view of a cassette useful with the
invention;
FIG. 19 is a schematic view of a circuit of the invention;
FIG. 20 is a schematic view of a stepper circuit of the
invention;
FIG. 21 is a schematic view of a phasor circuit; and
FIG. 22 is a schematic view of an oscillator circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and particularly to FIG. 1, the
numeral 1 generally designates a support or base. The base 1 may
suitably take the form of a rectilinear box or cabinet rendered
portable by handle and wheel arrangement 1a, for example.
Mounted as at 2, externally of the base 1 and for movement thereon,
is an arm element 3. The arm 3 is preferably formed of segments 3a,
3b articulated as at 4. At the distal end of arm portion 3b a
finger element 5 is articulated for movement toward and away from
distal arm segment 6, as indicated at 7.
A thumb-size electric motor 10 is positioned adjacent each of the
articulation points 2, 4 and 7, the motor at point 2 being mounted
on base 1 for movement control of arm segment 3a, the motor at
point 4 being mounted on segment 3a for movement control of segment
3b and the motor at point 7 being mounted on segment 3b for
movement control of finger 5.
While the single arm 3, formed of the portions 3a, 3b, and a single
finger 5 workable toward and away from the distal end segment 6 of
arm segment 3b are shown, it will be understood that more than one
of the assemblies indicated at 2-10 may be suitably carried on base
1. Similarly, while a single finger element 5 is shown in the
drawings, it will be realized that a suitable number of similar
finger elements could be carried at the distal portion of each of
the arms thus mounted on the base 1. For simplicity and clarity, a
single assembly 2-10 is illustrated and described herein, it being
understood that similar assemblies could be increased in number
without departing from the nature and scope of the invention.
It will be understood that the articulation-driving assembly is
repeated as often as necessary at the points 2, 4 and 7, for
example. As illustrated, the arm segment 3a is intended for
rotation about the point 2 in a single plane. Hence a single motor
10 and its driving-control connection are shown. The same is true
at points 4 and 7. Should it be desired to move the arm portions
3a, 3b and finger or fingers 5 in more than one plane, it will be
understood that additional motors 10 and associated driving-control
connections and articulation joints would be supplied at points 2,
4 and 7 for movement of the associated element in the desired
planes. Further, in such event, a wrist-simulating universal-type
connection with associated motors 10 and driving connections could
be supplied between the end of arm portion 3b and the finger
elements.
As best seen in FIGS. 10-16, motor 10 drives a shaft 11 carrying a
worm drive configuration 12. Secured to the element to be moved,
such as the arm portion 3b, is a gear member 13 having spaced,
parallel, peripherally toothed annuli 14, 15 having spaced teeth
14a, 15a, respectively offset for alternate engagement by worm gear
configuration 12. The annuli 14,15 are separated by and supported
in a ceramic or insulation block 16 axially bored as at 16a.
Rotation of the worm gear 12 in opposite directions thus enables
corresponding rotation of gear 13 and vertical motion of the arm
portion 3b in relation to arm portion 3a, for example.
The motor 10 is illustrated in FIGS. 2-9 and includes a motor
housing 20 serving as a magnetic flux retainer. Rotatable within
the housing 20 is a crisscross wound barrel armature winding 21.
The winding 21 surrounds a disc magnet 22, the magnet being
suitably centered about the axis of winding 21 and fixedly secured
to an insulating housing divider wall 22a as by an adhesive for
example. Inwardly, radially directed wires 23, preferably five in
number, are suitably connected to and extend from the winding 21,
having their inner ends extending axially in circumferentially
spaced, parallel relationship to form the commutator shaft 25. A
lightweight, plastic disc 25a with axial collar 25b supports wires
23 and shaft 25 rotatably with winding 21.
A pair of brushes 26,26a are provided for transmittal of DC current
and are hereafter referred to as commutator brushes. The brushes
26,26a are spring urged against the shaft 25 on opposite sides
thereof for sequential contact with the machined, reduced curvature
surfaces 23a of wires 23 as the shaft 25 formed thereof
rotates.
A shaft extension or slipring collar 27 is secured to the distal
end of the shaft 25 formed of wires 23. The collar or extension 27
includes a first ring 28 and a second ring 29 with an insulated
area 30 positioned therebetween. The area 30 may, for example, be
filled with an appropriate varnish. The area within collar 27 and
between wires 23 therein is filled with an insulation material such
as plastic 30a and glue 30b. The ring 28 is suitably secured to one
of the wires 23, as indicated at 31, a silver compound being
suitable for the connection 31. The ring 29 is suitably secured to
a second wire 23 by a second supply of silver compound, as
indicated at 32.
A brush 33 is yieldingly urged against the ring 28 of collar 27 and
a brush 33a is yieldingly urged against the ring 29 of collar 27,
the brushes 33,33a being hereinafter referred to as the slipring
brushes. The brushes 26,26a and 33,33a are carried by closure plate
10a.
The motor shaft 11 is suitably geared, as indicated generally at
40, to the center shaft 25d which is secured by boss 25c to plate
25a for rotation therewith in response to delivery of electrical
energy to the motor 10, shaft 25d extending through magnet 22 and
wall 22a. A ratio of 59 to 1 has been found effective between
armature shaft 25d and output shaft 11. Appropriate electrical
conductors, such as the wires 41, are connected through suitable
terminals to the commutator and slipring brushes.
A DC current across the commutator brushes will cause a
corresponding rotation of the armature 21, the speed of rotation
being substantially proportional to the voltage applied, the motor
shown being capable of an armature speed, for example, of up to
40,000 r.p.m. In response to any rotation of the armature 21 and
commutator shaft 25 a sinusoidal wave form is produced across the
slipring brushes 33,33a, generating a low-level AC signal of up to
0.5 volts.
A DC current pulse across brushes 33,33a orients the armature
winding 21 to a predetermined point at which the polarity of the
winding 21 is opposite that of permanent magnet 22, i.e. north on
winding 21 overlies south on magnet 22 and south on the winding
overlies north on the magnet, a continued application of that
current holding the armature in orientation. A reverse DC current
across brushes 33,33a displaces the winding polarity, reversing
south to north and vice versa, reorienting the armature with the
magnet and "stepping" the armature half a revolution.
The base 1 is conveniently of sufficient size to contain the
circuitry and recording and playback mechanism described
hereinbelow. Hence it will be understood that conductors such as
those indicated at 41 in FIG. 2 conveniently extend within the arm
segments 3 a,3b, from each of the individual motors 10 to the base
1.
Referring now to FIGS. 10 and 11, it will be observed that
articulation point 4 is illustrated. The arm portion 3a carries the
motor 10 and a fixed shaft 50 on which arm portion 3b is pivoted.
The arm portion 3b may include an end section 3c, for example, from
which the ear 3d may extend for pivotal connection with the rod 51
of a suitable air or hydraulic piston and cylinder booster means
52.
Since the specific internal details of the booster means 52 form no
specific part of the present invention, a conventional such means
may be employed and the details are not shown or discussed. It will
be understood, however, that a suitable source of air or hydraulic
pressure (not shown) may be positioned within the base or console
1. From such source suitable conduits 53 are provided for
conveyance of pressure to opposite sides of a piston (not shown)
within the means 52, the direction of such pressure being
controlled by conventional solenoid valve 54, the details of which
form no part of the present invention. As discussed below,
appropriate electrical signals are delivered to the solenoids 55,56
of valve 54. The rod 51 has an excursion greater than the intended
extent of rotation of gear 13 in either direction and suitable
exhaust means 57 are provided for the boost system 51-56.
Carried on section 3c for rotation about shaft 50 therewith and
retained by nut 3e is the gear member 13, above described. It will
be observed in FIG. 16 that the gear member 13 is insulated from
the arm segment 3b and nut 3e by insulation 16. As indicated below,
the gear structure 13 serves the additional function of an
electrical switch means and is provided with a flexible, elongated
conductor 13a secured to annulus 14 and a flexible, elongated
conductor 13b secured to annulus 15.
It has been found effective to provide a substantial ratio between
the worm 12 and gear 13. Preferably, for example, a gear 13 having
an outside diameter of 1.025 inches and a diametrical pitch of 72,
having 72 teeth in each annulus, provides a ratio of 72 to 1 with a
worm 12 of corresponding tooth size and approximately one-fourth
inch in diameter. The resultant total gearing between armature
shaft 25d and the gear 13 is 4,248 to 1.
As indicated above, the two metal-toothed annuli 14,15 of gear
structure 13 are insulated from all structures other than the worm
12, as well as from each other. The worm 12 is permanently
grounded. The teeth of annulus 14 are slightly offset or axially
misaligned from those of annulus 15 and are separated by the
thickness of the insulation 16 therebetween. Worm 12 and annuli
14,15 are positioned to provide for a clearance of the worm out of
contact with the teeth of either annulus. Hence worm 12 is in
contact with a tooth 14a or with a tooth 15a or with neither. Thus
in FIG. 13 worm 12 is seen in contact with a tooth 14a. In FIG. 14
worm 12 contacts a tooth 15a and in FIG. 15 worm 12 is centered
between and entirely out of contact with either set of teeth.
A start-return point or "home base" device is illustrated in FIGS.
11 and 17. The device takes the form of a ring or bezel 60. The
ring 60 is rotatably mounted about shaft 50 and retainer 50a and
yieldingly held in selected rotational position by a suitable
means, such as the ball or pin retainer 61 carried by arm segment
3a, for example. Retainer 61 is yieldingly urged toward the
circumference 62 of ring 60 in which suitably circumferentially
spaced pockets 63 are formed for locking reception of element
61.
An annular surface 64 of bezel ring 60 carries spaced electrical
energy transmitting crescent surfaces 65,66. Elongated, flexible
conductors or leads 65a,66a are connected, respectively, to
surfaces 65,66. As best seen in FIG. 11, the crescents 65,66 are
suitably insulated from the ring 60 as by the insulation layer 68.
Opposed ends of surfaces 65,66 are spaced to form the
nonconducting, null or void area 70. A similar spacing exists
diametrically therefrom on the ring 60 as indicated at 71. Carried
by and for rotation with the arm segment 3b, for example, is a
wiper 72. The wiper 72 rides on the wiper surface 65 or 66. Since
the intended positioning of ring 60 and the intended movement of
arm segment 3b are known, the placement of leads 65a,66a adjacent
the area 71 provides more than sufficient wiping surfaces for the
wiper 72.
An outer surface 73 of the bezel 60 is exposed to view of the
operator. An appropriate indicia, such as the arrow 74, is formed
on the surface 73 in alignment with the nonconducting or null point
70. Thus electrical contact is provided between wiper 72 and either
of the crescent surfaces 65,66, except when the wiper is aligned
with the area 70 which is the start-return or "home base" point
selected by the operator in rotating and positioning the bezel 60.
The wiper 72 being continuously grounded, contact thereof with
surface 65 will ground lead 65a and contact with surface 66 will
ground lead 66a. As discussed below, the resulting circuits are
effective to drive motor 10 in one or the other direction to
produce movement of arm segment 3b until the wiper 72 reaches the
prepositioned nonconducting area 70.
As shown in FIG. 18, a conventional magnetic tape 85 may be of
substantial width to provide for recording thereon of a track for
each articulation point in the assembly of the invention and may be
carried in a conventional cassette structure 86 thickened to
receive the tape 85.
Referring now to FIG. 19, there is illustrated a circuit and
associated components effective to achieve the goals of the present
invention. A recording and playback head 100 may be of
conventional, well-known construction. A "program-operate" switch
103 is shown in its full line "operate" position. Accordingly, a
series of switches aligned on the drawing with the manually
operable switch 103 are shown in their "operate" positions.
Similarly, a high-low relay 104 is supplied with energy of the
order of 24 volts and controls a series of switches aligned
therewith in FIG. 19, said switches being shown in their "low"
position.
A program or recording amplifier 106 has associated therewith the
sensor 108. Indicated at 109 is a low speed control or stepper
component. A phase detector comparator or phasor component is
indicated at 110. A frequency multiplier is shown at 111. An
operate or playback amplifier 112 has sensor 113 associated
therewith. An oscillator 114 is shown adjacent a rewind relay 115
which, it will be understood, controls the four switches shown as
aligned therewith in the drawing. A second rewind relay is shown at
116, controlling the switches shown therebeneath. A homing and
rewind double switch button is indicated at 117. Gear switch leads
13a,13b are connectable, respectively, to the two upper terminals
of oscillator 114 and are connected to relays 118,119 for
respective control of the switches shown adjacent, aligned with and
beneath each of said relays.
Referring now to FIG. 20, the slow-speed control or stepper 109 is
illustrated. The input terminals at the left of the drawing have
the filter F thereacross. Beyond the filter F the multivibrator M,
formed of transistors T1,T2 and associated components, delivers
voltage to points A or B and thence respectively to a dual
silicone-controlled rectifier formed of SCR1, SCR4, SCR2, SCR3 and
associated components. A transistor T3 is fed one signal from the
input for activation of a relay K1 and a transistor T4 controls a
relay K2. Transistor T5 is fed a signal from the input and controls
a relay K3 which, in conjunction with relay K1, will deliver energy
through their respective switches to solenoid 55 or 56. At the
lower center right of FIG. 20 the arrows indicate outputs to the
commutator brushes 26,26a. The arrows at the upper right-hand
portion of FIG. 20 indicate outputs to the slipring brushes 33,33a.
Those at the lower left center indicate outputs to solenoid valves
55,56.
Referring now to FIG. 21 in which the phaser 110 is illustrated,
the input from a first amplifier is indicated at the terminals
120,121 and their transformer 124. The input from a second
amplifier is indicated at terminals 122,123 and their transformer
125. The transformers are connected to a diode ring D having its
diametrically opposed points X and Y. Voltage at ring D controls a
transistor T6 and associated components which in turn can vary the
output of the phaser 110, as indicated by the arrows in the
right-hand portion of FIG. 21.
An effective oscillator component 114 is illustrated in FIG. 22.
The three input terminals shown in the center bottom of FIGURE 22
appear in the left-hand side of oscillator 114 in FIG. 19. In the
left-hand portion of FIG. 22 the two terminals appearing at the
bottom of oscillator 114 in FIG. 19 appear, the left bottom
terminal being connected to a transistor T7. The adjacent bottom
terminal is connected to a motor interrupter 130 which in turn
drives a cam 131 for operation of cam switch 132, the oscillator
114 including transistor T8 and associated components, the output
of oscillator 114 being indicated by the arrows at the right-hand
portion of FIG. 22 and corresponding to those shown in the
right-hand portion of the oscillator 114 in FIG. 19. Since
amplifiers 106,112 and their associated sensors 108,113 are of
standard construction and well know in the art, the same are not
internally illustrated herein.
The use and operation of the invention are as follows:
As shown in FIG. 1, the operator places his own arm and fingers
over the arm 3, segment 6 and finger 5. Where necessary, the arm
portion 3b may be suitably strapped or otherwise secured to the
forearm of the operator, the arm portion 3a may be suitably secured
to the upper arm of the operator and the finger parts 5,6 may be
secured to the thumb and index finger of the operator. The operator
then manipulates or moves the arm portions 3a and 3b and finger 5
to perform the function normally performed by the operator in his
daily work routine.
For purposes of simplification and clarity, a pair of elements 5,6
may be considered as substituted for the thumb and index finger,
respectively, of the operator. The normal work routine of the
operator may be considered as the grasping of a workpiece or part
at a first level, the raising of the part to a higher level and the
release of the part at said higher level, all in one vertical
plane.
It will be understood, as set forth above, that movement of the
part in a horizontal plane, rotation of the part about a
horizontal, inclined or vertical axis, joinder of the part to a
second part (grasped and held by another arm 3a,3b and fingers
5,6), etc., may all be accomplished through the provision of
additional elements corresponding to those described herein. Thus
virtually any work routine presently accomplished manually by
manual production workers seated, for example, before a machine, a
conveyor belt or the like, may be accurately and continuously
accomplished by the teachable, programmable, work-repeating
mechanism of the invention.
Considering the simplified work routine illustrated herein, for
example, the operator presses finger element 5 toward the finger
portion 6 to grasp the workpiece therebetween. As this is done, the
gear 13 at the pivot point 7 is rotated in response to movement of
the finger 5. The operator then raises finger elements 5,6, with
the piece grasped therebetween, raising, at the same time, the arm
segments 3a,3b. At the normal point the operator then opens the
finger elements 5,6 to release the piece and returns to grasp a
second piece. As the arm segments 3a,3b were raised and lowered,
the gears 13 at points 4 and 2 were rotated. If the piece part be
heavy, and in view of the length of arm 3, fluid power booster
means, such as the air cylinders and associated controls 51-57 may
be employed, particularly at points 2 and 4.
In view of the gearing involved, provision has been made for
electrical assistance permitting movement of the gears 13, worms 12
and motors 10 in response to manual movement of the arm 3 and
finger elements 5,6.
In the programming stage, manual movement of arm segment 3b, for
example, would cause rotation of gear 13, yet mechanical
transmittal of motion from gear 13 to worm 12 is not feasible.
Rotation of gear 13, however, produces contact of the teeth of one
of the annuli with the worm, thus grounding that annuli through its
lead 13a or 13b and producing a circuit therethrough, the resulting
circuit, as described below, being effective to drive the motor 10
in one or the other direction corresponding to the direction of
movement imparted to the arm by the operator. Thus the grounding of
worm 12 through one or the other of annuli 14,15 functions as a
single-pole, double-throw switch and the motor 10 is employed to
drive the worm in correspondence with motion imparted to the gear
13 by the operator in moving the arm segment 3b, for example. As
the operator continues motion of the segment 3b, the motor 10 is
continuously stepped in response to energy delivered as a result of
worm and gear contact.
The direction and extent of rotation of gears 13 at slower speeds
is recorded in the form of a suitable tone or signal on tape 85 for
later delivery to motors 10.
As the motors 10 are actuated in response to faster, continuous
manual manipulation of the arm 3 and fingers 5,6, the direction,
speed, and duration of each rotation of each motor is recorded on
the tape 85 in the form of a suitable tone or signal.
The operator then removes his arm and hand from the arm 3 and
fingers 5,6. The tape 85 is rewound to its original position.
Thereafter the tape 85 is traversed across the head 100 and the
signals on the tape are played back through head 100 and amplifier
112 to the motors 10 to cause the arm 3 and fingers 5,6 to repeat
precisely the functions accomplished when the arm 3 and fingers 5,6
were secured to the arm and fingers of the operator.
In the programming step or phase of operation, the switch 103 is
placed in its dotted line or "program" position. Thereupon all of
the switches shown in alignment with the switch 103 in FIG. 19 are
placed in their upward position.
It will be understood that the bezel 60 may be set with or without
the supply of electrical energy to the assembly of the invention.
If each of the arm and finger segments are positioned in alignment
with the arrows 74 and thus with the nonconducting areas 70 of
their associated bezels, the operator will manually engage elements
3,5,6, turn "on" a suitable power supply switch (not shown), turn
switch 103 to "program" and perform his normal work routine.
If the bezels 60 are set at the desired start-return points or
"home bases" and any of the arm or finger segments are not aligned
with the associated arrows 74, a bezel circuit such as that shown
in FIG. 19 may be activated, upon positioning of switch 103 at
"program" to cause such arm and finger segments to move into
alignment with their associated bezel arrows. In such bezel control
mode, the arm and finger segments are responsive solely to the
information received from the bezel, designating the dislocation
from the home base point and the direction of run to arrive
thereat. The rate of startup, run to home base and stop is fixed or
constant in the bezel control circuit.
For simplicity the movement of arm segment 3b in relation to arm
segment 3a is considered, it being understood that the description
thereof applies equally to the simultaneous or sequential movements
of all of the other arm and finger segments. In the simplified
showing of FIG. 1, for example, each of the motors 10 has its
discrete track on tape 85 and its circuit such as that illustrated
in FIGURE 19.
Accordingly, as arm segment 3b is rotated about pivot shaft 50
motion is imparted to gear structure 13. Upon contact of either of
the teeth 14a or 15a with worm 12 a circuit is created. With switch
103 in "program" position, the control system is set to accept
program information from the gear 13 and to provide electrical
assistance permitting and abetting manual manipulation of the
structure.
The gear-switch structure 12,13 is thus connected to the oscillator
114 for production of the selected "low" signals of 4,000 or 6,000
cycle per second signal frequencies, depending upon the direction
of rotation, clockwise or counterclockwise, of gear structure
13.
A high-low relay 104 is supplied with energy of the order of 24
volts and controls the switches shown in alignment therewith in
FIG. 19. As shown, the full line position of said switches
corresponds to the low speed position of relay 104. The output of
oscillator 114 is connected to amplifier 106 with relay 104 in low
speed configuration and the output of amplifier 106 is connected to
sensor 108, recording head 100 and stepper 109.
Either the 4,000 or the 6,000 cycle input signal to oscillator 114
will thus be grounded as gear 13 is rotated in one or the other
direction, resulting in transmittal of that frequency from the
oscillator 114 to amplifier 106. The sensor 108, detecting the
signal to be one of the preselected low speed indicators, energizes
the relay 104 to position the switches controlled thereby in their
"low" position shown.
The output of oscillator 114 is thus amplified and recorded by
amplifier 106 on the tape 85 through head 100. At the same time the
same signal is fed from amplifier 106 to stepper 109, producing
continuous application of a reversing DC voltage to the slipring
brushes 33,33a of motor 10 and a momentary DC pulse to the
commutator brushes 26,26a providing both operating energy and
direction information to the motor in the low speed mode, the
stepper 109 distinguishing between the 4,000 OR 6,000 cycle signal
to produce direction information. Activation of motor 10 thus frees
gear 13 to rotate.
AS the operator manipulates the elements 3,5 at a higher speed,
sensor 108, sensing the higher frequency output of amplifier 106,
cause relay 104 to switch into its "high" mode, placing all of its
switches in their upper positions. As elements 3,5 are manually
manipulated in this mode, motor 10 is operating and worm 12 and
teeth 14a,15a are continuously making and breaking contact,
producing momentary closures of the switches of relays 118 and 119
or neither to feed from source S either a positive or negative or
no voltage to commutator brushes 26,26a, giving the motor 10
accelerating or decelerating pulses, the combination of which will
control the speed of the motor so that worm 12 maintains, in
effect, a centered position between teeth 14a,15a throughout any
displacement of gear 13 and gear 13 is thus freed to rotate in
either direction.
With the switches controlled by relay 104 in their high position,
the output of the slipring brushes 33,33a of motor 10 is connected
to frequency multiplier 111 from whence a greatly multiplied signal
is delivered to amplifier 106 for recording by head 100 on the tape
85.
Since amplifier 106 remains continuously connected to recording
head 100 while the switch 103 is in its "program" position, the
proper frequency signals are continuously applied to head 100 and a
continuous record of the actions of gear 13 and motor 10, their
speed and direction of rotation as well as any periods of
inactivity, is formed on the tape 85.
When the operator completes his work function, the arms and finger
segments of the invention are preferably returned to the proximity
of their "home base" or start-return points, resulting in alignment
of said segments with the arrows 74 on their associated bezels 60.
Normally the workpiece or pieces will have been disengaged prior to
such return. When desired, the programming may be completed upon
disengagement of the workpiece or pieces and the arm and finger
segments be left at the position of such disengagement, the bezel
control circuit being relied upon to establish the arm and finger
segments at their home base position.
In any event, upon the disengagement of the workpiece or pieces,
and the consequent completion of the work program, a suitable
rewind signal of a discrete frequency, such as 8,000 cycles, for
example, is supplied to and deposited on tape 85 by operation of a
suitable button switch 117. Said signal will be later sensed by
sensor 113 to activate a rewind mechanism in tape transport 135.
Various types of tape-transport and winding means may be employed
without departing from the spirit of the invention.
Depression of momentary rewind/homing button 117 sequentially
closes two separate switch paths. Since elements 3,5 are stopped,
the switches controlled by relay 104 will be in their "low"
positions shown. The first closed path connets ground to the lower
left side input of oscillator 114 causing the oscillator to
generate the discrete, e.g., 8,000 cycle, tone which is fed through
amplifier 106 and recorded on tape 85 through record head 100.
As button 117 is depressed further, the second path is closed which
applies ground to the rewind relays 115,116, causing the relays to
operate their associated switches. The rewind signal input to the
oscillator is thus disengaged and the 4,000 and 6,000 cycle
directional signal inputs from the bezel 60 are connected to
oscillator 114. Relay 115 also closes a path to the left-hand
bottom terminal of the oscillator causing transistor T7 to place
that terminal at ground potential to energize the motor interrupter
130 and also to hold the rewind relay 115 operated.
With the interrupter 130 energized, the operate path of the
oscillator circuit is interrupted by cam 131 and switch 132 at a
predetermined rate of approximately 30 pulses per second to produce
a predetermined speed at which elements 3,5 return to their home
base positions. Thus a stream of pulses of either 4,000 or 6,000
cycle frequency, depending on the direction of run required to home
base, is generated by the oscillator 114 so long as ground is
received from bezel 60. When the home position 70 is reached and
ground is removed, the signal is removed from the base of
transistor T7 thereby releasing the motor interrupter 130 and the
homing relays 115,116 simultaneously and causing the oscillator to
cease functioning.
When the operator desires to operate the mechanism of the
invention, the foregoing programming phase having been completed,
the switch 103 is placed in its "operate" position positioning all
of its aligned switches in their "operate" position as shown in
FIG. 19. At the same time, as in the programming stage, the tape
transport 135 will be activated by a suitable connection (not
shown) with switch 103 and tape 85 will be moved across head 100
for playback of the tape.
The signals on tape 85 are amplified in amplifier 112 and sensed by
sensor 113. At the outset, one of the predetermined low speed
signals, of 4,000 or 6,000 cycles per second, for example, will be
sensed, causing sensor 113 to activate relay 104's "low" side and
thus to position its controlled switches in their "low" position as
shown in FIG. 19.
The low speed signals are conveyed to stepper 109, which converts
the burst or pulses of 4,000 or 6,000 cycle signals to DC reversals
which are held in alternate polarity across slipring brushes 33,33a
of motor 10, each reversal producing a 180.degree. rotation of the
motor. The stepper 109, as described below, detects whether the
signal is 4,000 or 6,000 cycles, thus indicating clockwise or
counterclockwise direction, respectively, and the bias element of
the stepper will accordingly supply a momentary DC pulse, positive
or negative depending on direction, to the commutator brushes
26,26a of motor 10.
As the frequency received from tape 85 and head 100 changes from
the 4,000 or 6,000 cycle per second format to the high mode
frequency range, the sensor 113 energizes the high-low relay 104 to
its high position, throwing the switches aligned therewith in FIG.
19 to their upper position. Accordingly, the output of amplifier
112 will be directed into the phasor 110; the output of amplifier
106 will also be directed into phasor 110; the output of phaser 110
will be connected to the commutator brushes 26,26a of motor 10
through the switches controlled by relay 118 or relay 119.
The inputs from amplifiers 112,106 to phasor 110 are compared in
its phase-detector circuit. Depending upon the relationship of said
inputs, a controlled higher or lower DC voltage is applied by
phasor 110 to to commutator brushes 26,26a to regulate the speed of
motor 10 and to ensure its identity with that recorded on tape 85
in the programming step described above.
Referring now to FIG. 20, the output of amplifier 112 or 106 is
delivered to the low speed control or stepper 109 in the form of
pulse bursts of either 4,000 or 6,000 cycles per second
frequencies, producing in either case a voltage peak at the
appropriate midpoint of the two circuits shown across the inputs
and applying a positive potential to the trigger input of a
multivibrator formed of transistors T1,T2 and associated
components. Capacitor C1 filters out the 4,000 or 6,000 cycle
frequency which makes up the pulse leaving only the pulse envelope
as the triggering signal at the emitters of the two transistors
T1,T2, the transistors T1,T2 operating alternatively on successive
pulses. Thus a positive DC triggering pulse is produced
alternatively at points A and B. The pulse delivered at A appears
also on the gates of dual silicone-controlled rectifiers SCR2 and
SCR3 causing them to conduct and to produce a current from the
positive 24 -volt supply shown through resistor R2, through SCR2 to
slipring brush 33a, through the armature winding to brush 33,
through SCR3 and R3 to ground. The alternating pulses appearing at
point B appear also on the gates of rectifiers SCR1 and SCR4,
producing a current flow through R1, through SCR1 to slipring brush
33, through the armature winding to brush 33a, and through SCR4 and
R3 to ground. Thus the stepper circuit delivers a DC current
continuously to the slipring brushes 33, 33a but the stepper
reverses the direction of that current in response to each 4,000 or
6,000 cycle per second pulse received, each such reversal resulting
in a 180.degree. rotation of motor 10.
Signal inputs from the 4,000 -cycle filter across the input from
amplifiers 112 or 106 are fed to transistor T3 causing it to
conduct and to operate relay K1, the relay K1 being supplied as
shown with a low power supply of the order of ten volts. Activation
of relay K1 delivers a positive 1.5 volts from the source indicated
to commutator brush 26 for a short pulse at the start of any 4,000
-cycle pulse burst. Signal inputs from the 6,000 cycle per second
filter are fed to transistor T5 causing it to conduct and to
operate relay K3 and thus delivering a negative 1.5 volts to
commutator brush 26. Transistor T4 is caused to conduct in response
to conduction in the multivibrator formed of the SCRs and
associated components, the period of conduction of T4 controlled by
its input circuit. With T4 conducting, current flows through the
winding of relay K2 and a ground pulse is applied to DC brush
26a.
Thus the output of the slow-speed control illustrated in FIG. 20 is
shown as delivered directly to the slipring brushes 33,33a and thus
to the sliprings 28,29 of motor 10 to apply DC reversals at a rate
controlled by the input to the slow-speed control unit 109 and to
provide driving force for the motor 10. At the same time, the
circuit of stepper or slow-speed control provides a biasing
potential to the DC brushes of the motor through relay K1 or K3 and
K2 to ensure the correct, clockwise or counterclockwise, direction
in the rotation of the motor produced in response to the power
reversals supplied to brushes 33, 33a.
The phasor circuit, schematically illustrated in FIG. 21, is
designed to provide close control of the motor within the range of
phasor operation, i.e., in the high-speed mode. There is
substantial overlap in motor r.p.m. between low and high mode
operation, the staccato or stepping operation in low mode being
distinguishable in such respect from the continuous, steady
operation in high mode.
With relay 104 and its switches in the "high" or upper positions,
terminals 120, 121 are connected through amplifier 106 and
frequency multiplier 111 to the slipring brushes 33, 33a of the
motor 10. The signal at terminals 120, 121 is therefore a reading
directly from the motor of its speed of rotation. The form of the
signal is a sign wave multiplied by a preferred factor of eight
through frequency multiplier 111 and amplified in amplifier 106 to
a level suitable for detection. The signal received at phasor
terminals 122, 123 is from amplifier 112 and is the same signal
previously recorded on tape during the programming operation of the
invention.
The signals thus received at terminals 120, 121 and 122, 123 are
fed through their respective transformers 124, 125 to the diode
ring D. When the input signals are of identical frequency and
phase, the voltage across points X and Y of ring D will be zero and
phasor 110 will deliver its normal or reference output. As either
phase or frequency deviates, a voltage will appear across the
points X-Y, such voltage being positive when the input from one
transformer exceeds that from the other and negative when the
reverse condition exists. Through the appropriate circuitry
illustrated the voltage across X-Y controls or biases transistor T6
which in turn controls the phasor DC output current employed to
drive the motor 10 through its commutator brushes 26, 26a. A 6-volt
power supply is indicated at 126.
Thus, as motor 10 begins to increase in speed the frequency input
at transformer 124 leads the prerecorded signal at input
transformer 125, producing a negative voltage across points X-Y and
reducing the current through transistor T6 and thus to the motor,
resulting in a slowing of the motor speed. Similarly, as input
frequency at transformer 125 exceeds that at transformer 124 a
positive voltage is built up across points X-Y, causing transistor
T6 to conduct more heavily and increasing the current to the motor
and increasing its speed correspondingly. The circuit control is
such that the virtually instantaneous modulation or change in motor
speed, synchronizing it under virtually absolute control with the
prerecorded signal frequency on tape 85 ensures that the motor
response called for by the taped signal can be accurately and
minutely repeated, virtually without variation an indeterminate and
substantially unlimited number of times. Thus, so long as the
desired work function remains unchanged, the mechanism of the
invention will continue to perform said work function without
interruption and without reprogramming.
When the programmed operational cycle is completed, the 8,000-cycle
tone recorded onto tape 85 at the end of the programming cycle, as
described above, is sensed by sensor 113 and translated into a
ground at the output shown at the bottom of the sensor 113 in FIG.
19. This ground bypasses button 117 and is applied to the
rewind/homing relays 115, 116, causing them to operate. From that
point on the rewind/homing cycle is identical to that which occurs
in the program mode as described above. The arm and finger elements
3,5 will be returned to their preset home base positions and the
tape will be rewound by means 135 for automatic repetition of the
work function.
Thus it may be considered that the operation of the invention
generally encompasses seven conditions or modes in which the
circuitry and various components illustrated in FIG. 19 are
variously operative.
In the program-low mode, contact of worm 12 with gear 13 grounds
lead 13a or 13b depending on direction of gear rotation. The
appropriate upper left-hand terminal of oscillator 114 is grounded,
delivering a corresponding signal to amplifier 106 from which it is
recorded on tape 85 through head 100. The same signal is delivered
through the stepper 109, stepping the motor in the correct
direction in response to each signal from gear 13 and delivering
motive power to motor 10 through its slipring brushes and biasing
or directionally urging motor 10 through its commutator brushes to
permit rotation of gear 13.
In the program-high mode motor 10 is driven directly by plus or
minus pulses from source S. Grounding of leads 13a or 13b activates
relay 118 or 119, respectively, determining whether a plus or minus
pulse is delivered to the commutator brushes. The AC output across
the slipring brushes is delivered through multiplier 111 to
amplifier 106 for recording on tape 85 through lead 100.
The end program-signal mode is employed but once in establishing a
given program. The system is always in program-low mode at the end
of the program. The first contact on depression of button 117
grounds the lower left-hand terminal of oscillator 114 to produce a
discrete signal recorded on tape 85 through amplifier 106 head
100.
The end program-rewind/homing mode occurs upon full depression of
button 117 activating rewind relays 115, 116. The lowermost switch
controlled by relay 115 holds the relay in operation after button
117 is no longer depressed. Since, as indicated, the system is in
the program-low mode, the output of oscillator 114 is triggered by
bezel 60 and delivered through amplifier 106 and the switches
controlled by relay 116 to the stepper 109. Thus, if the elements
3,5 are not in home base position, the bezel 60 will drive the
motor 10 through oscillator 114, amplifier 106 and stepper 109 to
return the elements 3,5 to their home base positions. At the same
time, the relay circuit will direct the tape transport 135 to
rewind tape 85.
In the operate-low mode the signals or tones from tape 85 are
played through the playback portion of head 100 through playback
amplifier 112 to stepper 109 which drives motor 10 as above
described, delivering DC reversals to the slipring brushes of motor
10 to step it in 180.degree.revolutions and delivering DC pulses to
the commutator brushes to provide direction information for each
such half-revolution. Stepper 109 also energizes the appropriate
solenoid 55 or 56 to operate valve 54 and boost 52.
In the operate-high mode sensor 113 detects the frequency signal
for high-mode operation and shifts the circuit. The varying
frequency signal from tape 85 through head 100 is delivered to
playback amplifier 112 and then to the two left-hand bottom
terminals of phasor 110. The AC output signal of motor 10 is
delivered through frequency multiplier 111 and amplifier 106 to the
two right-hand bottom terminals of phasor 110. Relay 118 or 119 is
held continuously grounded by the continuous grounding of gear 13
through its continuous contact with worm 12, under urging of
cylinder 52, in the high-speed mode. Plus or minus output voltages
are thus delivered to the commutator brushes of motor 10. When
booster 52 is employed it remains in full boosting status as it was
in the low mode, any change in direction requiring a passing back
through low mode and a redirecting of booster 52 prior to a further
high mode operation.
The bezel control-rewind/homing mode occurs at the end of the
operate cycle. Since the motion of elements 3,5 is ceasing, the
circuit will be in operate-low condition or mode. Sensor 113 will
detect the discrete end of program or rewind signal on tape 85 as
it is delivered by head 100 to amplifier 112. The bottom terminal
of sensor 113 will then activate rewind relays 115,116, bringing
bezel 60 into connection with oscillator 114, grounding one of the
upper left terminals thereof and producing the appropriate signal
to amplifier 106. Activation of relay 116 closes its switches,
bringing amplifier 106 into connection with stepper 109 to drive
the motor in the appropriate direction for return of the elements
3,5 to their home base positions. At the same time tape transport
135 rewinds and thereafter replays the tape, the work function of
elements 3,5 being thus automatically repeated as often and for as
long as desired.
* * * * *