US2445041A - Silhouette reproducing machine - Google Patents

Description

L L. A. SCHOLZ SILHOUETTE REPRODUCING MACHINE July 13, 194s.

2 sheets-Smm 1 Filed Jan. 1, 1945 July 13 1948- L. A. scHolfz 2,445,041

SILHOUETTE REPRODUCING MACHINE Filed Jan. 1, 1945 2 sham-sheet 2 INVENTOR.r

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Patented July 13, 1948` UNITED STATES PATENT oFFlcE 2,445,041 SILHOUETTE REPRODUCING MACHINE Louis A. Scholz, Dayton, Ohio Application January 1, 1945, Serial No. 570,937 s claims. (ci. 33423) (Granted under the act of March 3, 1883, as

The invention described herein may be manufactured and used by or for Government for gov.- ernmental purposes, without the payment to me of any royalty thereon.

This invention relates to apparatus for automatically reproducing silhouettes. The primary object of the invention is to provide apparatus which willbe useful in the printing arts for reproducing maps and other figures and diagrams of complicated configuration. The invention may also be useful in tool and die making as it may provide means to cut or grind tools and dies to conform with drawings, etc.

In the accompanying drawings showing diagrammatically a preferred embodiment of the invention:

Fig. 1 is a sectional elevation of the apparatus:

Fig. 2 is a top plan View of the same;

Fig. 3 is a wiring diagram;

Fig. 4 is a cross section on an enlarged scale of one of the photocell units, for use with transparencies; and

Fig. 5 is a similar view of another form of photocell unit, for use with positive prints.

Referring particularly to the drawings, the silhouette I0 to be copied is on a translucent sheet of paper or the like which is laid on a ground glass or other flat light-transmitting support I2 arranged directly over a series of electric light bulbs I3 which are illustrative of any source of light. The ground glass sheet I2 and light bulbs I3'are preferably on a table (not shown) which provides the principal'support and framework for all the parts. The light from source I3 will pass through the paper II and any opaque design, figure or pattern on said paper will stand out by contrast with the illuminated portions of the paper sheet, so that light-sensitive elements to be described may be energized and de-energized when moved overthe paper. If the silhouette to be reproduced is on an opaque background, the source of light will be above the silhouette, which may be supported on the opaque top of the table, the silhouette then being reproduced by the effect of reflected light on the lightsensitive elements.

Secured rigidly to the top of the table are a pair of parallel, level rails I5, I6 on which a carriage Il rolls by its wheels I8. An extension I9 of the carriage serves as a nut, being threaded on a lead screw 20 which is supported on the table parallel to rails I5, I6 and which is driven by a motor 2I through reduction gearing 22. An undercarriage 23 is supported on parallel slides 24 amended April 30, 1928; 370 0. G. 757) beneath carriage I1 but spaced above the table top, and a lead screw 25 engages a nut 26 xed to the undercarriage, lead screw 25 being parallel to slides 24 and at right angles to rails I5, I6. A motor 2l drives lead screw 25 through reduction gearing 28. Obviously the undercarriage will move back and forth above the surface of the table or paper support I2 whenever carriage Il is moved, and it will travel at right angles to the movement of carriage I'I whenever motor 2l is energized, and these movements are independent of each other. A scribing instrument 29 is fixed on an arm 30 secured to nut 26, or some other part of the undercarriage, so that the scribing instrument partakes of all movements of said undercarriage. Scribing instrument 29 may be replaced by a drill or grinding tool inthe event a tool or die is to be made.

Secured to the undercarriage are a pair of photocell units 3|, 32 whose construction will be described in detail below. Both units 3 I, 32 have pointed lower ends, and both are disposed at an acute angle to the top of the table or paper support I2, and symmetrically to a vertical plane midway between the units. Light transmitted through or reflected from the paper I I will enter both units and will activate photocells 33, 34 (Fig. 3) to energize certain control circuits as will be described, to cause motors 2|, 21 to be energized thereby to move the scribing instrument over a sheet of paper (Fig. 2), to trace a line which will faithfully reproduce the silhouette or diagram on paper I I. The photocell units 3|, 32 each serves as an independent light pickup or scanning means for a small portion of the surface of paper II, and the portions so scanned are always a. very small finite distance apart. This arrangement permits one photocell unit to scan a black area at the edge of a silhouette, at the same time the other photocell unit scans a white area close to but outside the silhouette.

A typical photocell unit 3| designed for use with transmitted light may be of the construction shown in my copending application Serial No. 549,106 filed August 11, 1944, and matured into Patent No. 2,386,816 of October 16, 1945. Herein unit .3l consists of a photocell 33 mounted in one end of a sealed casing 35 (Fig. 4) which excludes al1 light from the cathode except the light rays admitted through an achromatic lens system, here shown as a convex lens 36 and concave lens 31, fixed inside the casing. The tapered end 35a of the casing has a light aperture 38 at its extremity. As explained in the copending application mentioned above, the aperphotocells, units may be used like the one of Fig. Fig, 5, which consists of a photocell 40 at the upper end of a light-tight casing 4|, and a mirror 42, with 50% reflectance, set at an angle of 45 relative to the longitudinal axis of casing 4|. A converging lens 48 is so located as to focus rays of light reflected by mirror 42 from lamp 44 on a narrow aperture 4l at the lower, tapered end of the casing. Lamp 44 may have a reflector 48. 'I'he light rays passing through aperture 45 are reflected by the surface of the nontransparent sheet |I and pass back through the mirror to the photocell 40 which is activated accordingly. It will be clear that there will always be two photocell units of one type or the other, each at an acute angle to the table top as already explained, and that the photocell units scan" the silhouette whose outline is to be reproduced in accordance with thev invention. A number of prior patents, for example, the Cook Patent No, 2,154,974 dated April 18, 1939, disclose the broad idea of using a pair of symmetrically disposed photocell units in machines employing cutting tools for duplicating work.

Now referring to Fig. 3, the photocells 33, 34 are each coupled to an amplifier 41, 48 respectively, and each amplifier is coupled on one side to a main lead 49, which is connected to a source of electricity not shown. The other main lead I8, connected to the other side of said source, is coupled to the opposite sides of the amplifiers through lead 5|, wires 52 and 53, slenoids 54 and 55, and wires 58, 51. Solenoids 5455 are each parts of two double pole, double throw relays which include movable contactors 58, 59 respectively, that are moved into one position when the solenoids are energized, and into another position when the Solenoids are de-energized. In Fig. 3, contactors 58, 58 are shown in the de-energized position, which is the position when no current is flowing through either photocell 33, 84. Movable contactor 58 engages ilxed contacts 80, 8| and contactor 59 engages xed contacts 52. 83 in this de-energized position. The fixed contacts for contactors 58, 58 when in the energized position are shown at 68,v B1 and 84, 8l. Contact 84 is connected by a lead B8 with one movable contact of a 3pole stepping relay 88 to be described, while contact 61 is connected by a conductor 1|| with a resistor 1| which in turn is connected to the coil 12 of said stepping relay. The other side of coil 12 is coupled to lead 48 through a conductor 13 and a conductor 82. Another resistor 14 is connected between contact 8| and conductor 82. Resistors I1 and 14 are employed to insure that motor 21 and coil 112 both get the proper amount of current since the motor and'coil have different electrical characteristics and are not adapted to carry the same current. Coil 12 actuates an armature 15 which carries contactors 18, 11 and 18 of the stepping relay, and these contactors move between fixed contacts 18, 88, 8| and 82, 88, 84 o1' the relay. Lead 88 is connected to contactor 18. Contacts 18 and III are coupled to motor 21 through wires 88 and 88 respectively, while contact 8| is connected to one side of motor 2| by a wire 81. Another wire 88 connects the other side of motor 2| with contact 84. Thus the closing of contactor 18 against contact 8| causes motor 2| to turn in one direction, and closing of the same against contact 84 causes reversal of said motor.

4 Contact 82 is connected with contact 88 by a wire 88, and contact 88 is connected with contact 19 by a wire 88; this arrangement being-conventional and effecting reversal of the circuit of m0- tor 21 when contactors 18, 11 close against contacts 18, 88 on the one hand and 82, 88 on the other. A lead 8| couples contactor 11 with contact 82 of the double pole relay which the photocells control. To complete the circuit of the stepping relay, a lead l2 couples contactor 18 with main lead 48. Motor 2| is connected to main lead 5l by a conductor 88 and motor 21 is similarly connected by a conductor 84.

The stepping relay I8 is three-pole, doublethrow type having a time-delay action. I'he relay action is accomplished by well-known actuating devices so that the relay contactors remain on either of the opposite sets of contacts until the solenoid 12 is energized. Thus if the relay contactors are moved from contacts 18, 11 and 18 to contacts 82, 88 and 84 by an impulse from the solenoid 12, the contactors will remain in the latter position until the solenoid 12 is again energized. The operating mechanism of the relay 69 by which this stepping or impulse action is produced forms no part of the present invention. In fact the stepping or impulse relay is well-known in the electrical relay art and the specific details thereof may vary according to preference and operating conditions. In the present machine a light-duty relay is satisfactory and if desired the relay contactors may be merely pivoted members having an overcenter spring action and actuated from one position to another by a reciprocating solenoid armature. Relay 69 is so designed that contactor 18 breaks sooner than contactors 11 and 18, which control motor 21.

Assuming that the main switch (not shown) is closed to energize main leads 49, 88, motor 2| starts and continues to run without stop while the machine is operating. This is because movable contactor 18 closes the motor circuit, whether it is closed against contact 8| or contact 84. Thus carriage |1 travels in the direction required by the direction of rotation of lead screw 20 and continues in this direction until motor 2i is reversed by operation of the stepping relay, as will be explained. As carriage i1 moves it causes the pair of photocells to move over paper and when the photocells pass over a black area, such as a silhouette, both relay coils 54, 55 are de-energized and current will be supplied to motor 21 to cause the undercarriage to be moved to the left or into a white area. When both photocells record a white area, both relay coils 54, Il will be energized and current will be supplied to move the undercarriage to the right or into a black area. When one photocell records a white area and the other simultaneously records a black area, no current will be supplied to motor 21, and accordingly the undercarriage will remain stationary, except as it moves with the main carriage. The motor control circuit including the series-connected relays actuated by photocells 38, 84, amplifiers 41, 48 and relay coils 54, 55 forms what may be termed a discriminating circuit, since it has a selective action depending on the photoelectric effect produced in the two separate photocell units.

Reversal of movement of both carriages is effected by the time delay or stepping relay 48. When motor 21 is running, a voltage drop is produced across resistor 14, which will cause a current to now through coil 12 to move armature 1l toward the opposite contacts of stepping relay Il. As stated, this relay is a time delay relay and approximately one second is preferably required for amature to move from the upper position as viewed in Fig. 3 to the lower position. Relay ll is also provided with spring over-travel contacts (not shown) so that the contacts and contactors will remain engaged during the delaying action oi the relay.

For a summary of the operation of the present machine consider Fig. 2 where the silhouette I0 represents an outline of the 4State of Ohio. Starting at thelower left-hand corner of the outline it may be assumed that the photocell units 3| and 32 are both scanning a black area. Therefore relay contactors 58 and 59 of the photocell relays will both be in the upward position shown (Fig. 3), and current will ilow in the lead 9| to supply the motor 21. Therelay 69 will now be energized with contacter 18 being moved to contact 8l more rapidly than contactors 16 and 11 are moved to contacts 82 and 83. In any event, as soon as the contactors take this new position the motors 2| and 21 will operate to vmove the photocell units to the left and also upwardly, or in mapping terminology to the west and to the north. When the photocell units reach the straight line boundary on the west, the photocell unit 3| will scan white and the 4photo-- cell relay contactor 59 will move downwardly.

This will break the circuit to motor 21 thus stopping movement of the photocells to the west. However the motor 2| will continue to operate in the same direction until the circuit through resistors 1i and 14 is again closed; thus the photocell units continue their movement to the north with photocell unit `3| scanning white While photocell unit 32 scans black. This tracing movement will continue until the photocell units reach the northwest corner of the map.

As the photocell units 3| and 32 both scan white at the northwest corner of the map, due to continued rotation of motor. 2| in one direction as explained above, both contactors 58 and 59 of the photocell relays will be in the downward position on the contacts 64 to 61. Now a circuit to motor 21 will be completed and the relay 69 will again be energized. It will be remembered that the relay contactors 16, 11 :and 118 were in the downward position due to theinitial actuation of relay 69. Now -however these contactors will be stepped back to the contacts 19, 480 and 8|, with the contactor 18 being moved to contact 8| more rapidly than contactors 16 and 11 are moved to contacts 19 and 80. 'I'he motor 2| will now be reversed to move the photocell units to the south.- The motor `21 will start up to move the y photocell units to the east before the contactors 16 and 11 have left the contacts 82 and 83. Then when the contactors '16 and 11 do reach the contacts 19 and 80, the motor 21 will reverse and the photocell units will move south and west into the black area adjacent-the northwest corner of the map. Now the photocell relays will again move together to the position of Fig. 3 again actuating relay 69. It will be noted that each ac-- tuation o! the photocell relays in unison, as the units 2| and 32 move from white to black and vice versa, instantly reverses the motor -21 and that the motor again reverses when the contactors 16 and 11 are actuated after about one second time delay. However this joint action of the photocell relays in alternately scanning white and black, as along the north boundary of the map, reverses the motor 2| only one time for each action of the photocell relays since the changes in the photocell relays affect the motor 2| only by their combined action on the relay 89. 'I'he result lis that in moving the photocells along a generally horizontal boundary, the motor 2l continually reverses and the motor 21 does likewise except that it has a double reverse action which results in the photocell units follow-y ing a zig-zag path, with a minor back-tracking action due to the double reverse of motor 21 for each shift in the photocell relays from one position to the other. Because of the searching action of motor 21 it may be termed a scanning control motor, while the motor 2| may be termed f a scanning reverse motor.

Continuing the zig-zag movement along the northern boundary of the map I0, the photocell units will finally scan only white at the northeast corner as they run oil' the silhouette. Just as at the northwest corner, the photocell units will move a little to the east and south before the contactors 16 and 11 of relay 69 have moved to a new position. Then the units will move south and west until the photocell unit 3| reaches the map area, whereupon the corresponding photocell relay will be deenergized and the circuit to motor 21 will be broken. Motor 2| will continue to operate to carry the photocell units south along the straight line eastern boundary, and the motor 21 will not be in operation until the map outline bears off to the southwest. The photocell units 3| and 32 will both scan white at that time, energizing both of the photocell relays to start the motor 21 and reverse the motor 2| by action of relay 69. The photocell units will now move a little to the east and north before the contactors 16 and 11 of relay 68 have moved to a new position. Then the units will move north and west until the photocell units both reach a map area, whereupon the photocell relays will be deenergized at the same time and relay 69 will be actuated to reverse motors 2| and 21. Thus the photocell units will begin following the irregular southern boundary in a zig-zag path toward the southern tip of the map at Illa and continuing from there to the starting point, at the southwest corner of the map. It should be understood that the horizontal or east-west alignment of the photocell units makes possible a break in the circuit to motor 21 only when the units are scanning straight north-south lines such as form the western boundary of the State of Ohio and part of the eastern boundary. When this condition does occur the motor 2| operates alone, with the circuit to motor 21 through the photocell relays broken. Because of the searching or scanning action of the motor 21, the motor 2| will always be operating in the correct direction as the photocell units approach a northsouth straight line boundary, thus the motor 21 stops but the motor 2| merely continues to operate to move the photocell units along the straight line boundary. This situation is of course a very special case and one which will seldom be encountered in actual practice. Following the theory of operation as above set out it can be shown that the machine will trace any silhouette completely, regardless of its shape or extent of irregularities. The zig-zagging action described is of minute amplitude and therefore the trace obtained by the scribing instrument 29 is smooth and accurate.

'Ihe embodiments of the invention herein shown and described are to be regarded as illustrativeonly and it is to be understood that the invention is susceptible to variations, modifications and changes within the scope oi the appended claims.

What I claim is:

1. A silhouette controlled duplicating machine of the character described comprising, in combination, a support; for the silhouette; means adjacent to said support and movable over the same in two opposite directions; other means carried by said movable means and movable relative thereto in two opposite directions transverse to the path of movement of the first-mentioned movable means; a pair of photocells carried on the second-mentioned movable means to scan portions of the silhouette slightly spaced apart; a pair of reversible motors for 'driving said two movable means independently; a discriminating circuit controlled by said photocells and including a pair of relays each actuated by separate photocells for connecting a power` source to one motor for forward operation, for reverse operation and also for disconnecting said power source from said one motor; and a third relay controlled by said discriminating circuit for connecting said power source to the other motor and embodying a motor reversing means for reversing the direction of both motors after an interval of time during which said one motor is continuously connected for either forward or reverso operation.

2. In a silhouette controlled duplicating machine having a silhouette supporting surface with two connected surface traverse elements having paths of movement transverse to each other; the

improvement comprising a pair o! photocells carried on one traverse element to scan portions of the silhouette slightly spaced apart; a pair l reversible motors for driving said two traverse elements independently; a discriminating circuit controlled by said photocells and including relays actuated by separate photocells for connecting a power source to one motor for forward operation, for reverse operation and also for disconnecting said one motor; and an additional relay under control of said discriminatin! circuit for connecting said power source to the other motor for forward operation and embodying means for reversing both motora simuJtane-- comprising a support for the silhouette; a ilxst4 movable means on the support and movable over the same in two opposite directions; a second movable means carried by said first movable means relative thereto in two opposite directions at right angles to the path of movement oi' said rst movable means; a pair of silhouette scanning photoceils carried on said second movable means to scan portions of the silhouette slightly spaced apart; a pair ot reversible eiectricmotors for driving said rst and second movable means independently; a discriminating circuit controlled by said photocells and including a pair of series-connected relays each actuated by separate photocells for connecting a power source to one motor for forward operation, for reverse operation and also for disconnecting said one motor from the power source; means controlled by said series-connected relays for connecting said power source to the other motor for forward operation and for reversing both motors after a brief interval of time during which said one motor is continuously connected to said power source for either forward or reverse operation; and means nxed to said second movable means to reproduce the outline of said silhouette.

LOUIS A. BCHOLZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,226,677 Vikhman Dec. 31, 1940 2,331,337 Meyer Oct. 12,1943

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