US1871380A

US1871380A - High-speed recorder

Info

Publication number: US1871380A
Application number: US362613A
Authority: US
Inventors: Esther L Legg
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1929-05-13
Filing date: 1929-05-13
Publication date: 1932-08-09
Anticipated expiration: 1949-08-09

Description

Aug. 9, 1932. J. w. LEGG HIGH SPEED RECORDER Filed May 15, 1929 2 Sheets-Sheet 1 Aug. 9, 1932. J, w. LE G HIGH SPEED RECORDER 2 Sheets-Sheet 2 Filed May 15, 1 929 Patented Aug. 9, 1932 UNITED STATES PATENT OFFICE.

JOSEPH W. LEQG, DECEASED, LATE OF WILKINSBURG, PENNSYLVANIA, BY ESTHER L.

LEGG, ADMINISTRATRIX, OF WORCESTER, MASSACHUSETTS; ASSIGNOR T0 WEST- INGHOUSE ELECTRIC AND UFACTURING- COMPANY, A CORPORATION OF PENN- SYLVAINIA HIGH-SPEED RECORDER Application filed May 13, 1929. Serial in. 362,613.

This invention relates to recording apparatus and particularly to oscillographs which are designed to record high-speed oscillograms.

The object of this invention is to provide apparatus of the above-mentioned type for recording a large number of very high-speed ogeiillograms on a comparatively short length 0 l In practicing this invention there is employed a galvanometer deflecting-element and means for slowly and uniformly deflecting said element, a straight filament lamp for supplying a beam of light which is reflected from said element to a slowly moving film, and means for passing a plurality of cylindrical lenses in rapid succession through the regiected beam of light and past the moving When recording an oscillogram, the defiectingelement is vibrated in accordance with a characteristic of the quantity that is to be recorded and these vibrations are superimposed on the aforesaid slow uniform deflection.

Other features and'advantages ofthis invention will appear from the following description taken in connection with the accompanying drawings, in which Figure 1 is a schematic diagram of the apparatus and electrical connections employed in one embodiment of my invention.

Fig. 2 is an end elevational view of the apparatus shown in Fig. 1.

Fig. 3 is a face view of a section of film showing the arrangement of the oscillograms which are recorded by apparatus constructed in accordance with my invention.

Fig. 4 is a side view, partly in section, of the.actual structure which may be employed in constructing the apparatus shown schematically in Figs. 1 and 2.

F ig. 5 is a View of the apparatus taken on the line V-V of Fig. 4. o

Fig. 6 is a schematic diagram of the apparatus employed in a modification of my invention,- and Fig. 7 is an end elevationalview of the apparatus shown in Fig. 6.

' Referring to Figs. 1 and 2, the apparatus includes a. galvanometer deflecting-element 1 of well-known construction which comprises two parallel conductors supported at each end and positioned within a magnetic field supplied by means of a permanent magnet 2. A small mirror 3 is cemented to the conductors so that, when a beam of light 4 strikes ported in a light shield 7. The light shield 7, which comprises a wall of opaque material surrounding the lamp 6, is provided to prevent rays of light from reaching the film 5 directly from'the lamp.

straight-filament lamp 6 are located inside a drum 8 which is open at one end. The drum 8 is rotatably mounted by means of a shaft 9 which is secured to the closed end of the drum. The drum 8 may be belted to a motor (not shown) by means of a pulley 10 secured to the shaft 9.

A plurality of cylindrical condensing lenses 11 are located around the periphery of the drum,.each lens 11 being secured to the drum opposite a rectangular slit 12 therein. The film 5 is positioned opposite the drum 8 and provided with atsupply spool 13 and a take-up spool 14 by means of which the film maybe slowly moved past the drum. .While in the preferred embodiment of my inven-' tion the film is moved in a direction opposed to the direction of movement of the cylindrical lens adjacent to the film, it is' evident that the film may be moved in the same direction as the direction of movement of the cylindrical lens so long as the film and lens do not move at the same speed.

The beam of light 4 is projected against the cylindrical lenses 11 and interior of the The galvanometer element 1 and the drum 8 in the form of a vertical narrow band of light. This is accomplished by placing a piano-convex spherical lens 15 (Figs.

iou

' 20 and a plate 21.

4 and 5) in the wall of the galvanometer casing 16 opposite the galvanometer mirror 3 and so positioning the straight filament 17 with respect to the spherical lens that the image of the filament is located on or near the surface of the film 5. With such an arrangement, the light rays from, the

straight filament 17 pass through the spherid trated schematically in Figs. 1 and 2, 1s shown cal lens 15 to the galvanometer mirror 3 an thence again through the lens 15 and to the film 5. The length of the filament image, which is approximately the width of the light, band through which each cylindrical lens 11 passes, may be determined by the following equation: 1 length of image distance between mirror and film length of filament distance between mirror and filament 7 As each one of the cylindrical lenses 11 passes downwardly through the narrow band of light, it focuses a portion of the narrow band on the moving film 5, as a moving point of light. In this way, when the deflecting-element 1 is stationary, each lens 11 traces a straight line on the film 5 as the lens moves downwardly or, if the deflectingelement 1 is being vibrated, each lens 11 traces a curve on the film. It will be noted that the movement of the beam of light reflected from the vibrating deflecting-element 1 is at right angles to the movement of the cylindrical lenses 11 and the film 5.

, The electrical quantity to be recorded may be supplied to the deflecting-element 1 through an amplifier. The amplifier. comprises a three-electrode vacuum tube 18 of the usual type having a filament 19, a grid The filament 19 is heated by means of a battery 22 connected thereto through a rheostat 23. The filament 19 and grid are connected to input terminals 24 by means of

conductors

25 and 26. A 0 battery 27 is provided for putting the proper negative bias on the grid 20. A suitable potential is supplied to the plate 21 by a B battery 28 which has its negative terminal connected to the filament 19 and its positive terminal connected to the plate 21 through a conductor 29, the deflecting element 1 and a conductor 30. v

The circuit is so arranged that at the time the deflecting-element 1 is being deflected by the quantity which is to be recorded, it is beingslowly and uniformly deflected to move the band of light from one side of the film 5 to the other side. This is accomplished by means of abattery 31, one terminal of which is connected to one terminal of the deflecting element 1 through the

conductors

32 and 29. The winding 33 of a potentiometer is connected across the battery 31. The rotatable contactor arm of brush 34 of the potentiometer is connected to the other terminal of the deflecting-element 1 through a variable .resistance 35 and. the conductor 30. During the operation of the apparatus, the cont ct arm 34 is so rotated that a varying potential is impressed across the deflecting-element 1. Accordingly, a uniformly varying current passes through the deflecting-element to cause a uniform deflection. The magnitude of this deflection may be controlled by adjusting the resistance 35.

The construction of the apparatus, illusin detail in Figs. 4 and 5. The apparatus includes a light-proof'casing 36 which comprises a bottom plate 37, an end wall 38, a

cover 39 and a side wall 40. This part of the casing may be formed integrally from any suitable material, such as a fibre composition. Y

The other side wall of the casing 36 is removable and comprises a flanged plate 41 which may be secured to the rest of the easing by means of screws 42. The removable side wall has an opening 43 centrally located therein through which the drum shaft 9 extends.

The other'end wall of the casing is also removable and comprises a late 44 which may be secured to the end "0 the casing by means of screws 42. The end plate 44 has.

a rectangular opening 45 centrally located therein.

The drum 8 is rotatably mounted inside the casing 36 and is sopositioned adjacent to the removable side wall 41 and to a circu lar flange 46 on the side wall 40 that light is excluded from the interior of both the easing and the drum. The shaft 9, which rotatably supports the drum 8, is attached, by means of flanges 47, to a plate 48 which is secured to the end ofthe drun1.8 by screws I 55. The shaft 9 is journaled in a bearin 49 which is mounted on a base plate (hot shown). A collar 50 prevents longitudinal movement of the shaft.

The light-proof casing 36 is mounted on the same base plate as the drum 8 by means of a supportingrod 51. The rod 51 is securely attached to the side of the/casing 36 by means of a flange 52, while the outer end of the rod 51 is mounted on the base plate by means of a clamp 53 and a pedestal (not shown). The inner end of the rod 51 has attached thereto a supporting structure for the lamp 6, light shield 7 and galvanometer 16.

The supporting structure comprises a horizontally positioned U-shaped member 54 to which the galvanometer casing 16 is bolted or otherwise secured. A member 65 which projects from the left-hand side of the U- shaped piece 54 is attached to the side wall 40 of the casing to serve as a brace for the supporting frame.

The portion of the supporting structure to which the light shield 7 and the straight-filament lamp 6 are attached comprises a vertieal U-shaped member 56 which has the bott m 9f the U twisted at an angle with respect to the horizontal. The light shield 7 and the straight-filament lamp 6 are attached to the bottom portion of the U-shaped member.

A film holder 57 is mounted on the removable end wall 44 of the casing opposite the rectangular opening 45. The film holder may be of the type described in my copending case, Serial N 0. 195,400, filed May 31, 1927. The inside wall of the film holder 57 has a rectangular opening therein which is in alignment with the rectangular opening 45. With the above-described arrangement, a rectangular section of film faces the interior of the casing 36 so that it may be exposed by a beam of light passing through one of the cylindrical lenses 11. The film may be driven at the proper speed by means of a pulley 58 belted to a motor (not shown).

Each condensing lens 11 is so adjusted that it will focus a portion of the band of light on the film 5 as a point of light.

To record a series of high-speed oscillograms, the drum 8 is rotated at high speed. At the same time, the film 5 is moved at a speed which is low as compared with the peripheral speed of the drum 8, one one- "hundredth of the drum speed, for example,

and the potentiometer arm 34 is rotated at a speed which preferably bears .a certain fixed relation to the film speed. The quantity to be measured is impressed on the input terminals 24 of'the amplifier.

Assuming the potentiometer arm 34 to be located at one end of the potentiometer resistance 33, the deflecting-element 1 will be so positioned that the band of light is projected to a position opposite one edge of the film 5, the right-hand edge of the film in Fig. 2 in the case being assumed. In Fig,

3, the top of the film is shown at the lefthand side of the figure, as indicated by the arrow.

Referring to Fig. 3, if no potential is impressed on the input terminals 24 at first, the straight line curves

numbers

1, 2, 3, 4 and 5 will be recorded, each cylindrical lens 11, in succession, tracing a straight line on the film 5 as it passes throu h the band of light. Record number 1 has ieen traced by one lens. During the time that this record was being traced, the rotation of the potentiometer arm 34 caused the deflecting-element 1 to gradually shift into .adifferent plane. Therefore, when the next lens 11 reached the upper edge of= the band of light, it began tracing a curve (curve number 2) slightly to one side of the first curve. Also, during the time the first record was being traced, the film 5 had moved upward a small amount. For that reason, curve number 2 begins slightly below curve number 1.' By the time theupper edge of the band of light has been reached by a cylindrical lens 11 for the sixth time in the example illustrated in Fig. 3, a variable potential has been impressed on the input of the amplifier. Accordingly, the deflecting-element 1 is rapidly deflected in accordance with the variable potential to vibrate a point of light laterally with respect to the film 5. At the same time, the condensing lens 11 moves the point of other group of curves (curves 14, 15, etc.)

across the film.

The speed of the film 5 with respect to the rotating arm 34 of the potentiometer should be such that, during the time the rotating arm 34 is causing the band of light to move from the right-hand edge of the film 5 will move through a distance equal to the length of a single record. With such adjustment, when the deflecting-element 1 returns to its original position,the first record of the second group of records will begin just below curve number 1. Hence, the records will not be superimposed.

In Fig.2, the positions of the oscillograms.

which are recorded are indicated by dotted lines. In this figure, only five oscillograms to a group are illustrated.

The modification of this invention which is illustrated in Figs. 6 and 7 is identical with the embodiment described above except that the cylindrical lenses 11 are positioned over radial slots 59 in a disc 60 which, like the drum 8 in the other embodiment, is made of opaque material. As shown in Fig. 7, the film 5 is positioned between the axis and the edge of the disc 60.

Various modifications may be made in this invention 'without departing from the spirit and scope thereof, and it is desired, therefore, that only suchlimitations shall be placed thereon as are shown by the prior art and set forth in the appended claims.

What is claimed as this invention: 1. In recording apparatus comprising a recording surface and mechanism for moving said recording surface, means for projecting a narrow band of light against said recording surface, a deflecting element for deflecting said band of light in accordance with the variations of an electrical quantity, means for moving said deflecting element into different planes while it is being deflected in accordance with said variations, and means for successively passing a cylindrical lens transversely through said beam, the longitudinal axis of said cylindrical lens being substantially perpendicular to the plane of said band of light.

'2. Recording apparatus comprising a recording surface, means for projecting a narsaid recording surface,

row band of light against said recording surface, a deflecting element for deflecting said band of light in accordance with the variations of an electrical quantity, means for moving said deflecting element into different planes while it is being deflected in accordance with said variations, means for successively passing a cylindrical lens transversely through said beam, the longitudinal axis of said cylindrical lens being substantially perpendicular to the plane of said band of light, and means for moving said recording surface in a direction opposed to the direction of movement of said lens at a speed different from the speed of said lens.

3. In recording apparatus comprising a recording surface and mechanism for moving said recording surface, means for projecting a narrow band of light against said recording surface, a deflecting element for deflecting said band of light in accordance with the variations of an electrical quantity, means for moving said deflecting element into different planes while it is being deflected in accordancewith said variations, and means for successively passing a plurality of cylin drical lenses transversely through said beam, the longitudinal axis of said cylindrical lenses being substantially "perpendicular to the plane of said band of light.

A. In recording apparatus comprising a recording surface and mechanism for moving said recording surface, means for projecting a narrow band of light against said recording surface, means for moving said band of li ht in a direction perpendicular to the plane 0% said band, means for deflecting said band in accordance with the variations of an electrical quantity during said first movement, and means for successively passing a cylindrical condensing lens through said band.

5, Recording apparatus comprising a recording surface, means for DrO ecting a narrow band of light against said recording surface, a deflecting element for deflecting said band of light in accordance with the variations of an electrical quantity, means for moving said deflecting element into different planes while it is being deflected in accordance withisaid variations, means for successively passing a cylindrical lens transversely through said beam, the longitudinal axis of said cylindrical lens being substantially perpendicular to the plane of said band of light, and means for moving said recording surface in a direction opposed to the direction of movement of said lenses at a speed which is low compared with the speed of said lens.

6. In recording apparatus comprising a recording surface and mechanism for movlng means for passing a beam of light along a predetermined path, means for deflecting said beam of light in accordance with a characteristic of a quantity of means for and against said recording surface, and means movable transversely of said path for focussing said beam of light substantiallyas a point of light for movement along the surface of said recording surface.

7. The combination with means for passing a beam of light along a predetermined path, deflecting said beam of light in accordance with a characteristic of a quantity, a recording surface with which said beam of light coacts, means movable transversely of said path for focussing said beam of light substantially as a point of light for movement along the surface of said recording surface,

and means for moving said recording surface in a direction opposed to the directionof the movement of said focussing means at a speed different from the speed of said lens.

8. 1n recording apparatus comprising a recording surface and mechanism for moving said recording surface means beam of light along a predetermined path, means for deflecting said beam of light in accordance with a characteristic of a quantity and against said recording surface, and

means comprising a cylindrical lens movable.

transversely of said path for focussing said beam of light substantially as a pointof light for movement along the surface of said recording surface. v 9. In recording apparatus comprising a recording surface and mechanism for moving said recording surface means for passing a beam of light along a predetermined path, means for vibrating said beam of light in accordance with a varying electrical quantity and against said recording surface, means for moving said beam of light across said recording surface while said beam is being vibrated in accordance with said quantity, a light shield movable transversely of said path, and a condensing lens carried by said light shield.

10. In recording apparatus comprising a recording surface and mechanism for moving said recording surface means for passing a for passing a beam of light along a predetermined path,

means for vibrating said beam of light in accordance with a varying electrical quantity and against said recording surface, means for moving said beam of light across recording surface while said beam is being vibrated in accordance with said quantity, a light shield movable transversely of said said path, and a cylindrical condensing lens car- 1 while said beam is being deflected in accordfor deflecting said beam of an'ce with said characteristic, 9. light shield 7 movable transversely of said path, a condensing lens carried by said light shield and means for moving said recording surface at such speed with respect to the speed of movement of said beam across said recording surface that said recording surface moves substantially the length of a record during the movement of said beam across said surface.

12. The combination with means for passing a beam of light along a predetermined path, of means for deflecting said beam of light'in accordance with a characteristic of a quantity, a recording surface with which said beam coacts, means for moving said beam of light across said recording surface while said beam is being deflected in accordance with said characteristic, a light shield movable transversely of said path, a condensing lens carried by said light shield, and means for moving said recording surface in a direction opposite to the direction of movement of said condensing lens and at such speed with respect to the speed of movement of said beam across said recording surface that said recording surface moves at least the length of a record during the movement of said beam across said surface.

In testimony whereof, I have hereunto subscribed my name the 20th day of April, 1929.

ESTHER L. LEGG,

Administratriw 0f the Estate of Joseph W.

Legg, Deceased.