US1880295A - Scanning disk - Google Patents

Description

Oct. 4, 1932. A. o. TATE lscmmum msx :med July 17; 1930 5 Shee'ts-Sheet 2 IVENTO 49% z: f fwaL ATTORNEYS O. TATE SCANNING DISK Oct. 4, 1932.

Filed July 17. 1930 5 SheetS-Sheet 3 ATTORNEYS Oct. 4, 1932. A. o. TATE SCANNING DISK med July 17. 1950 5 Sheets-Sheet 5 R O T N E vV W V.. B

M az, M 4 49431 TTORNEYS Patented Oct. 4, 1932 Uurrsn srarss ALFRED oRDE rami, or `rroiioiwr'o', oNTARIo, CANADAy SCANNING DISKV Application flled July 17,

'This invention relates to Scanning, and more particularly to a Scanning system in which the image is completely scanned iu more than one revolution of the Scanning element. V The invention is particularly applicable to a system utilizing a Scanning disk and provideS for Scanning aportion of the image during one revolution of the disk and a different portion in the next Successive revolution of the disk. If the image is divided into two parts the arrangement is such that alter-b nate halves of the image are scanned during Successive revolutions of the Scanning disk.

For the above purposel a shuttermechanism is provided in conjunction' with the scanning disk which reveals only a portionof the image at any one time. The shutter may be arranged so that alternate halves of the image are revealed during successivc revolutions of the Scanning element, or so'that a portion only of the image is revealed which corresponds to the instantaneous position of the Scanning ray.

The present invention is particularly useful in Scanning largeimages or in Scanning a small image with a large number of scanning channels andl permits the same to be accomplished without unduly increasing the size of the Scanning disk, or in the case of a standard size image and a standard Scanning system permits the size of the Scanning disk to be materially reduced.l

The invention will be particularly described as applied to a system involving a disk for Simplicity of description. It will be obvious, however, that various other scanning systems may be employed within the scope of the invention. It is also to be understood that the number of Scanning sections may be Varied and that applicant is not limited to a device which completely scans the image in every two revolutions.

The invention also consists in certain new and original features of construction and 1930. serial no. 468,'521.

believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its Operation and the manner of its organization may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which,

Fig. 1 is an elevation of Constructed in accordance invention; ,Fig 2 is a front elevation of a` shutter mechanism adapted to be used therewith;

Fig. 3 is a side elevation of the shutter iiehanism Showing its relationship bto-the Fig. 4 is a longitudinal section of the commutator; Fig. 5 isa section taken on the line 5-5 of Fig. 4; F ig. 6 is an elevation of a modified formof Scanning disk; Fig. 7 is a front elevation of a modified form of shutter; and

Fig. 8 is a side elevation of the shutter of Fig. 7 associated with a Scanning disk.

Like referenoe characters denote like parts in the several figures of the drawings.

In'the following description and in the claims parts will be identified by Specific names for convenience, but they are intended to be as generic in their application to Similar parts as the art will permit.

Referring to the drawings more in -detail the Scanning element shown in F ig. 1 comprises adisk 10 which is divided by a-plurality of concentric circles into a plurality of equal concentric areas 11 and is also divided by a plurality of radii into equal radian spaces 12. An image 13 is adapted to be scanned by a` plurality of apertures which a Scanning disk with the presentV extend from an aperture 14 located in the outer concentric area. to aperature 15 which is located in the inner concentric area. Each successive aperture around the disk is displaced one concentric area from the preceding aperture, the system forming in effect a two revolution spiral beginning at the outer edge of the image and ending at the inner edge. It is to be noted that each of the apertures is bounded by concentric circles and by radii of the disk. The apertures are accorddistance from the center of the disk.

In the above described disk it will be noted that beginning in the position shown, one revolution in aclockwise direction servesto completely scan the upper one-half of the imageand the next revolution will serve to completely sean the lower one-half of the image. Inasmuch as there are two apertures in register with the image at any given time it is necessary to provide a shutter mechanism which will render only one of said apertures operative. This mechanism is disclosed in Fig. 2 and compri'ses a frame 20 carrying a plurality of slides 21 and 22. Said frameincludes an aperture 23 which is adapted to register with image 13. Each set of slides 21 and 22 closes one-half of the aperture and eX- poses the other half to the action of the Scanning ray. Suitable channels 24, 25 Vand 26 are provided on frame 20 to permit slides 21 and `22 to have unimpeded movement.

For Operating said slides a pair of pivoted levers 27 are mounted on frame 20 and are connected at their ends with slides 21 and 22 respectively by links 28 and 29. Said levers are operated by a solenoid 30 which cooperates with cores 31, said cores being connected to levers 27 by means of links 32. The arrangement is such that when solenoid 30 is energized cores 31 are drawn inwardly causing pivotal movement of levers' 27' thereby Opening slides v 21 and closing slides 22. WVhen solenoid 30 is deenergized a suitable resilientmeans, such as spring 33 (Fig. 3) is associated with each of'said levers 27 to cause a reverse Operation, withdrawing cores 31 from solenoid 30, closing slides 21 and opening slides 22 thereby returning the apparatus to the position shown in Fig. 2.

For Operating solenoid 30 there is provided a commutator illustrated in Figs. 4 and 5 comprising a shaft 35 journalled in a housing 37 and carrying drum 38 of insulating material on which an arcuate commutator segment 39 is mounted. Said commutator 39 is 1,sso,295

electrically connected to shaft 35 as by screw 40 which extends through said commutator and into said shaft.

A brush 41 is mounted in a suitable brush holder 42 which is insulated from housing 37 and secured therein as by insulating cap 43. Said brush is resiliently pressed against commutator 39 by Spring 44 and is associated with an external binding post 45 by means of which it is connected to an external circuit. The circuit through solenoid 30 is completed by connecting the central portion of the solenoid to binding post 45 and connecting the two ends of the solenoid to an insulating binding post 46 which is mounted on frame 20. Said bincling post 46 may be connected to one side of a battery 47, the other side of which is grounded to frame 20 by being connected to screwv48.-,-'The circuit is accordingly complete from battery 47 to binding post 46, solenoid 30, binding post 45, brush 41, commutator 39, shaft 35, frame 20, screw 48 and thence back to the battery 47.

The above shutter mechanism is mounted as illustrated in Fig. 3 adjacent Scanning disc 10 which is carried on a suitable shaft 50. Said shaft also carries a sprocket wheel 51 which is connected by chain 52 to a sprocket wheel 53 which is mounted on shaft 35 of the commutator assembly. The sprocket wheels 51 and 53 are so related that the shaft 35 makes one revolution for each two revolutions of shaft 50. Commutator 39 is of such dimension that contact with brush tion of shaft 35 only. Accordingly, solenoid 30 will be energized during alternate one-half` revolutions'of shaft 35 and during alternate revolutions of disc 10. Slides 21 and 22 will thus be alternately closed during successive revolutions of disc 10. It will be evident that by properly selectmg the arrangement of the elements and the size of aperture 23, the device may be so designed that the upper half of image 13 will be exposed for Scanning during one revolution of disc 10 and the lower half will be eXposed for Scanning during the next revolution thereof; It is obvious that the number of sections into which the image is divided may be varied as desired, and the number of complete revolutions of the Scanning disc for a complete image may be correspondingly altered. Shaft 35 must be so adjusted with respect to shaft that the solenoid operates between successive apertures so that overlapping of the apertures on the image is prevented. V

It is to be noted that the disk of Fig. 1 is arranged to scan an image progressively from top to bottom and that each time the Scanning occurs in the same direction. This necessitates a rapid jump of the Scanning ray from the bottom to the top of the image between successive scannings. The disc il- 41 is completed through a one-half revolu- 1-00 lustrated in Fig. 6 provides for scanning the entire image in an undulating motion and eliminates abrupt changes in position of the Scanning ray. For this purpose disc of Fig. 6 is divided into a plurality of concentric areas and radial areas in the manner ponted out in connection with diskV 10. The apertures of disc 60 begin at a central area 61 and extend to the outer area 62 thenc-e returning to the central area 61 in a complete revolution of the disc. During the next revolution the apertures eXtend from area 63 which is adjacent area 61 to the inner area 64 and return to area 68. In two revolutions of the disc the Scanning ray extends from the center to the top of the image thence to the bottom of the image and thence returns to the center and forms a complete cyclic or undulating motion. It is to be noted that the apertures are so arranged that the outer and inner sections are scanned twice in succession. This permits a uniform intensity of light to be applied to the various parts of the image inasmuch as all parts of the image are scanned twice in two revolutions of the disk. It is obvious that the shutter arrangement shown in Fig. 2 may be associated With disc 60, and arranged to operate in the manner described in connection with disc 10 so that alternate revolutions of bthe disks scan the upper portion of the image between areas 61 and 62 and the other revolutions of the disk scan the lower portion of the image between areas 63 and 64.

This undulating motion of the Scanning ray permits the same -to be more readily followed by the eye and eliminates eye strain by avoiding sudden changes in position of the ra i; modified form of shutter which may be used in connection with disc 10 of Fig.` l is illustrated in Fig. 7 and comprises a disc having a spiral Opening 71 formed therein. Said Opening is of a Width equal to the radi'al Width of two or more apertures and, for example, may be made of a Width equal to four concentric areas. Spiral 71 begins at the outer edge of the disc opposite aperture 14 and extends to a point 180 displaced therefrom and opposite the central aperture of Fig. 1. During the next 180 it extends from the point opposite the central aperture to a point opposite aperture 15 at the bottom of the image. rI`he ends of spiral 71 overlap a. certain amount to permit a rapid shift from aperture 15 to aperture 14 between successive scanningof the image. This overlap will not interfere with the Operation of the disc inasmuch as no two apertures will Hs' be in register with the image and With spiral 71 at any one instant.

A method of mounting disk 70 is shown in Fig. 8. For this purpose disk 10 is secured to a shaft 50 as shown in Fig. 3 and is rotated s thereby. Disk 70 is mounted on a sleeve 72 which is carried on shaft 50 and is driven by two revolutions of disk 10. It will be evident,v

that the arrangement of Fig. 8 provides a continuously movable shuttergwhich so registers with the apertures of disk 10 that only one aperture is exposed to the image at any given time; he arrangement accordingly permits the apertures of disk 10 to be s'o arranged that more than one revolution of the disk is required to completely scan the image and yet prevents more than one aperture to be exposed to the image at any one time.

While the image 13 in the above system has been illustrated as keystone in shape for ease of description, it is obvious that a rectangular image may be obtained by employing a suitable aperture in conjunction with the Scanning disk, and that in a disk of commercial size the relationship between the size of the image and the radius of the disk isV such that only a slight keystone efi'ect is obtained. It is contemplated, for example, that with a one inch image, a disk having a twelve inch radius would be employed and that at least forty-eight apertures will be used therein. It is obvious, however, that the size of the disk and the number and disposition of the apertures may be Varied Within wide limits.

While certain novel features of the invention have been shown and described and are pointed out in bthe annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the deVice illustrated and in its Operation may be made by those skilled in the art without departing from the spirit of the in-` i vention.

What is claimed is:

1. A Scanning system comprising a scanning element having apertures arranged to completely scan an image in two revolutions thereof, a shutter mechanism mounted independent of said element and adapted to alternately reveal portions of said image, means for Operating said shutter mechanism comprising a solenoid, the arrangement being such that one-half ofsaid image is revealed when said solenoid is energized and the other half is revealed When said solenoid is deenergized, a commutator for intermittently Operating said solenoid and means for synchronizing said commutator with said scanning member whereby alternate halves of said image are revealed during successive revolutions of said member.

2. In a Scanning system, a Scanning member having a plurality of apertures therein adapted'to successively reveal an object, a

shiittermoiinted independent of said Inernber and in register With said apertures and adapted to re'veai said object in sections, said shutter comprislng slidabie members, pivoted levers associated therewth, electrical means for Operating said levers, and'rneans for controlling said-electrical means Whereby difierent sections of said image are revealed in successive revolntions of said Scanning member. f

In testimony Whereof I have hereunto set my hand.

` ALFRED ORDE TATE.

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