US3707254A - Aerial photography - Google Patents

Abstract

Discrete lengths of elongated web are both pushed and pulled through a complex path formed in part by spaced-apart guides made of porous material. Pressurized gas forced into the path through the porous walls creates gas layers over which the webs ride. Means are also provided for transporting the webs between stationary and moving paths.

Description

United States Patent Scott 1 Dec. 26, 1972 [54] AERIAL PHOTOGRAPHY 3,125,268 3/1964 l3a1'tholomay...; ..226/97 Inventor: Richard David Scott Camden, NJ. 3,468,606 9/1969 Wolf et al. ..226/97 UX 73 Assigneez C Corporation FOREIGN PATENTS OR APPLICATIONS [22] Filed: March 19, 1971 1,904,101 1/1969 Germany "226/97 [21] Appl' 126,112 Primary Examiner-Allen N. Knowles Attorney-H. Christoffersen [52] US. Cl ..226/97, 226/197 51 1111.0. ..B65h 17/32 1 1 AB TRA [58] Field of Search ..226/97, 7, 95,197,196; Discrete lengths of elongated web are both pushed 242/76 and pulled through'a complex path formed in part by spaced-apartguides made of porous material. Pres- [56] keferfmces Cit-ed surized gas forced into the path through the porous UNITED STATES PATENTS walls creates gas layers over which the web's ride. 1 Means are also provlded for transportmg the webs 3,245,334 4/1966 Long ..226/97 X between stationary and moving paths. 3,548,783 12/1970 Knapp ...226/l97 3,134,527 5/1964 Willis ..226/97 7 Claims, 7 Drawing Figures PNENIED HEB 26 m2 SHEET 1 U? a INVENTOR. char D. Scott ATTORNEY PATENTED DEC 25 1972 SHEET 2 0F 4 Fig 4.

ATTORNEY PATENTEU DEC 2 6 1972 SHEET 3 OF 4 I N VEN TOR. Richard D. Scott /QM ATTORNEY PATENTEU DEC 26 I972 SHEET 4 [IF 4 INVENTOR. Richard D. Scott fiaw nd X '1 AERIAL PHOTOGRAPHY The invention herein described was made in the course of a contract with the U-.S. Government.

BACKGROUND O THE DISCLOSURE Y There is a need in many art areas for apparatus for which is moving relative to the first. In the prior art much apparatus exists for permitting a web to be pulled through complex paths. However, where the web is of finite length, apparatus must be capable of both pushing and pulling it. The apparatus described in the present invention allows the web to be both pulled and pushed through many complex paths.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a mechanical schematic of an aerial panoramic camera which employs the present invention to guide discrete lengths of an elongated film web;

- FIG. 2 is a view, partially in section, showing a capstan assembly used to drive a web' in the apparatus of FIG. 1;

FIG. 3 is a perspective view of a curved web guide employed to guide the web through the apparatus of FIG. 1; 1

FIG. 4 is a mechanical schematic of a web transfer mechanism; i

FIG. 5a is a perspective view of a rotating camera mechanism employing the present invention;

FIG. 5b is a broken-away view of the rotating camera of FIG. 5a to illustrate the web guides contained within the revolving camera; and v FIG. 50 is a perspective showing of the stationary mechanism in which the camera of FIG. 5a is positioned.

SUMMARY OF THE INVENTION According to a feature of the invention, the walls of the web guiding passages may comprise elongated porous elements formed as parallel, developable surfaces. Gas may. be forced through the walls into the passages for creating gas layers between the web surfaces and the walls.

DETAILED DESCRIPTION Referring first to FIG. 1, which illustrates schematically an aerial panoramic camera, elongated webs of photographic film are stacked one on top of the other in a supply magazine 12. These webs may be 4 X constantly'to slowlyrotate by a motor coupled to 48 inches, as one example. A pick-up device 14 which, for example, may be asuction mechanism, removes the webs one at a time from the stack and moves each one into a capstan assembly 16. A webis moved via a series of other capstans (not shown) at appropriate places in the mechanism into rotating camera assembly 18 through opening 21. The camera assembly is caused the camera.

aperture plate 31 and lens assembly 32. The aperture plate may have an aperture 29 one-half inch high by the width ofthe film. A mirror 33 at a 45 angle relative to the plane of the page on which the drawing is reproduced permits an object, such as a section of terrain 34, to be recorded on the flattened portion 36 of the filmas the aircraft (not shown) transporting the camera proceeds in the direction of arrow 35. Webs 10 pass through the camera in serial fashion being propelled at appropriate points by capstans within the camera (which are not shown in FIG. 1) and emerge from the camera through opening 22. The webs are then guided to a web capture mechanism 24. The'webs 10 are guided-between first and second rolls of continuous webbing 26 and 28 respectively and onto a driven take-up roll 30. The film later may be removed from take-up roll 30 for processing.

Since rather complex transfer mechanisms are needed to pass the film between the fixed assemblies 12 and 24 and rotating assembly 18, it may seem logical to merely include all mechanisms within rotating camera 18. However, in'the type of camera contemplated, the weight of the film alone-may be of the order of 500 pounds and may equal the weight of camera 18 as it presently exists. Since the angular velocity of camera rotation must continuously'b'ear a fixed relationship to the speed of the aircraft over the ground, as the aircraft changes speed, so mustwthe camera. Increasing the weight of assembly 18, increases substantially the torque requirement and therefore weight of motor 20. In any airborne-equipment such as the contemplated camera, weight is always a problem.

In FIG. 1, no web guides are shown and only one typical capstan 16 is shown. Adescription of the actual web guides, the capstans and the mechanism for per mitting entry of webs 10 into revolving camera 18 will be given shortly in connection with other figures. Also, film webs 10 must be contained within a light tight container at all times (except when passing aperture plate 31) to avoid exposing the film.

Referring to FIG. 2, which shows, in cross section, a

capstan assembly suitable for use in the camera mechanism of FIG. 1, a web 10 (shown in phantom) is wrapped around capstan 50 in an arc of approximately The capstan is coupled to and driven by a servo, 7

capstan assembly. The inner walls of each of the plenums, that is, the walls next to the web 10, are made of a porous material such as "sintered bronze. These walls are numbered respectively 64, 66 and 68. The compressed gas exits through the porous walls 68 thereby forcing web into contact with the surface of capstan 5,0. The purpose of fingers S6 is to guide the web ll) out of the capstan assembly. For example, if capstan 50 is driven in the direction of arrow 70, air coming through wall 64 would tend to cause the web to wrap around the drum'in the vicinity of portion 72 of the drum. However, fingers 56 cause the web to be guided between inner and outer flanges 52 and 54 and to exit from the capstan assembly.

It will be noted that the capstan assembly has finger projections 56 on both the ingress and egress-sides of the assembly. While the fingers are not needed on the ingress side, the symmetrical arrangement shown permits the use of a single design ofcapstan assembly with the servo motormerely being wired for clockwise or counterclockwise motion of capstan 50. Alternatively,

left and right capstan assemblies might have to be provided to allow the assemblies to be placed wherever they are needed in the camera of FIG. 1.

Capstan assemblies are positioned in FIG. 1 at a distance apart less than the length of an individual film web. For example, if a web having a'length of four feet is used, capstan assemblies must be positioned a distance apart no greater than approximately 3 feet, nine inches. This will ensure that a web is at all times being pushed or pulled by at least one capstan assembly.- i

Referring next to FIG. 3, there is shown a curved web guide assembly suitable for use in guiding the web through curved regions 80 in FIG. 1. The curved web guide comprises first and second web guides 90 and 92, one on each side of the web 10 shownin phantom. The first and second web guides are spaced apart by spacers such as 94 a distance just sufficient to permit passage of web 10 therebetween. At opposite ends of the curved web guides are flanges 96, 97 which permit fastening the curved web guide to other web guiding members, such as, for example, the capstan of FIG. 2. Each of web guides 90 and 92 includes a plenum 100. A compressed gas, such as pressurized air from source 102, is forced into the plenums 100 via the orifice in tubing 104 connecting the compressed gas source with the plenums. I 1

The inner wall of each of web guides 90 and 92 (that is, the wall next to web 10) is made of a porous material such as sintered bronze. A gas under pressure in plenums 100 is thereby caused to escape through porous walls 106 and 108 and thereby lubricate the surfaces between which web 10 travels.

Each of the porous walls 106 and 108 is formed as a d evelopable surface. That means that the wall is formed without stretching, shrinking or kinking the metal in any way. This may be accomplished by wrapping a rectangular piece of the sintered bronze in helical fashion around a cylindrical mandral a fraction of a turn. Walls formed in this manner permit a web to be either pushed or pulled through thecurved guide without any tendency to move to either side. Spacers 94 are just that. They do not act to guide the web through the guide. (In practice, due tothe additional spacing between walls in excess of web thickness, a

very slight side thrust develops which may be corrected by lateral web guides placedin the guides to which a curved guide is attached.) It will be noted that the guide shown in FIG. 3 causesthe direction of the web to change through 90", while moving it from a first plane in the vicinity of flanges 96 to a second parallel but noncoincident plane in the vicinity of flanges 97.

By ending the curved portion'short of that shown in FIG. 3 or extending it for a further distance, the web can be guided through a turn of more or less than 90. The curved guide may be connected as mentioned previously to a capstan of the type shown in FIG. 2, to

another curved guide or to sections of straight guide as will be brought out more fully in connection with the description of FIG. 5. i

The mechanical schematic of FIG. 4 will be used to illustrate the apparatusused to move a web from a first mechanical assembly to a: second mechanical assembly moving relative to the first. Let it be assumed that assembly 110 which comprises everything to the left of and above web 10 (shown in phantom) is stationary. Further, let itbe assumed that assembly 112 which .comprises everything to the right of web 10 is revolving in the direction of arrow 114. The only exception is that support 116, having axis 117 about which assembly 112 rotates, is fixed relative to assembly 110. Then assumes that it is desired to move web 10 from fixed assembly 1 10 to rotating assembly 1 12.

Both the fixed and rotating'assemblies 110 and 112 include a capstan assembly 16a and 161), respectively,

of the type illustrated in FIG. 2. The leading edge of i the dashed line 122. The grooves cooperate with finger-like projections 124 on wall-126 which forms a portion of capstan drive assembly 16b. These fingerlike projections are similar to those shown in FIG. 2 and numbered 56. Wall 128 on moving assembly 1 12 is similar to wall except that it has no grooves in its inner surface.

In operation, rotating assembly 112 is caused to rotate constantly in the direction of 1 14 by a motor, not shown. The leading edge of web 10 is introduced into capstan 16a of the fixed assembly 110, the capstan being caused to rotate in the direction of arrow 130. By proper timing, the web is propelled from capstan 16a into the space between the two walls just as capstan 16b of moving assembly 112 is positioned opposite the capstan 16a. The surface speed of web 10, determined by capstan assembly 16a, must be greater than the surface speed of wall 128 relative to wall 120. Then web 10 will be driven into the space defined by walls 120 and 128. As the web enters the space between walls 120 and 128 the capstan assembly 16b may have reached a point beyond capstan-assembly (that is, lower than cap- "mai no grooves 122 of wall 120 ensure that the web will be driven into capstan assembly 16b. Capstan assembly 16b is driven in the direction of arrow 132 at a surface speed which is the difference between the I surface speed of capstan assembly 16a and the surface speed of wall 128 relative to wall 120. The moving web exits into the interior portion of revolving assembly 112 in the vicinity of opening 134 where it may be utilized for any purpose desired; 7

The length of walls 120 and 128 are determined by the length of web to be transferred and to the speed with which the web moves relative to rotating assembly 122. The longer the web or the faster the speed of assembly 112, the longer must be walls 120 and 128. Because the two walls 120 and 128.form arcs of cylinders about pivot axis 117 the spacing between the two walls remains constant as the one assembly moves relative to the other. While assembly 110 was described as being stationary and 112 was described as being fixed, these are relative terms. Also, while the walls 120 and 128 are shown as arcs of cylinders, they may in fact be flat such that wall 128 is caused to move linearly with respect to wall 120.

A mechanism similar to that illustrated in FIG. 4 may also be used to transfer webs from a moving to a fixed assembly with the followingmodifications; The rotation direction of the capstan in capstan assemblies 16a and 16b are reversed from direction arrows 130 and 132. Wall 128, not wall 120, contains grooves. The cooperating finger-like projections are part of capstan assembly 16a, not 16b. Then, if the surface speed of the capstan of capstan assembly 16b exceeds the relative surface speed between walls 120 and 128, the web will be driven into the space defined by the walls and into capstan assembly 16a. 7

FIG. 5a shows an-actual rotating camera assembly 18 such as was depicted schematically in FIG. 1, which is rotated by a motor 20 via hollow shaft 140. A sleeve 141 permits compressed air from a source-(not shown) to be passed through shaft 140 to camera 18 to provide lubrication in the various web guides to be described.

Wall 128 corresponds to the similarly numbered wall in FIG. 4. The capstan assembly 16b corresponds .to the similarly numbered capstan in FIG. 4 and is of the type illustrated and described in FIG. 2. A web (not shown) is guided between the exposed surface of wall 128 and another wall 120 fixed in space and illustrated in FIG. SC, to be described shortly. After the web is driven through capstan assembly 16b, it enters the camera body through opening 21. The web then traverse the interior of the camera assembly, in a manner to be described in connection with FIG. 5b, and existsat opening 22 shown at the back side (as illustrated) of the camera assembly. It then lies between and is guided by walls 162 and 164 to capstan assembly 16c. Capstan assembly 160 and grooved wall 166 form part of a transfer mechanism similar to that shown in FIG. 4. Here the inner moving wall 166 is grooved.

I FIG. 5b shows the camera with the exterior walls cut away to permit viewing the various web guide assemblies within the camera. The web 10, shown in phantom view, enters the camera body at opening 21. It then is guided through a curved web guide 170 of the type illustrated in FIG. 3. It will be noted that no pressurized gas lines are shown. This is to avoid increasing the complexity of FIG. 5b. However, the gas lines are present as shown in FIGS. 2 and 3 wherever needed. The web next passes between spaced web guides 172 and 174 which may be constructedwith porous inner walls and It will be noted that the web guides are substantially I separated in the vicinity of region 176. This allows for slack in the web between capstan assembly 16b (FIG. 5a) and capstan assembly 16d, for the purpose of improving servo control, and avoiding scuffing of the web.

In FIG. 50 rotating camera assembly 18, shown in phantom, is inserted in position in the fixed assembly 200. For the sake of simplicity, supply magazine 12 and capture mechanism 24, shown schematically in FIG. 1, have been eliminated from FIG. 5c. Assembly 200 contemplates being supplied from two supply magazines 12, each feeding into Y assembly 202. This may be useful where films of two different types maybe used (e.g. color and black and white). A web emerging from the base of Y assembly 202 is driven by capstan 16a into the space between wall 120, shown in FIG. 5c and 128, shown in FIG. 5a. The numbers 16a, and 128 correspond with similar components shown in FIG. 4. After a web emerges from revolving camera assembly 18,- it passes between wall 204 and grooved wall 166, FIG. 5a. A capstan assembly 16e contains finger-like projections, not visible, which cooperate with the grooves in wall 166, FIG. 5a. A web traversing the space between walls 204 and 166 is engaged by capstan assembly 16e and driven thereby through curved web guideassembly 206 to capture mechanism 24 (FIG. 1).

Having described the arrangement of the various components of the camera, its operation will now be described with reference as needed to FIGS. 1, 5a, 5b and 5c. An elongated web 10 is pushed from a supply magazine 12 through Y assembly 202 (FIG. 5c) and into capstan assembly 16a. During this time, camera assembly 18 is slowly continuously rotating. The timing of the entry of the leading edge of web 10 into capstan assembly 16a coincides with the position of capstan assembly 16b opposite capstan assembly 16a. Therefore, the web emerges between grooved wall 120 and wall 128 connected to the rotating camera assembly 18. Since the web 10 has a surface speed greater than the surface speed of wall 128 relative to wall 120, it will be driven into capstan assembly 16b. Finger projections 124 (FIG. 5a) on capstan assembly 1611 cooperating with the grooves in wall 120 ensure that the web will captured by capstan assembly 16b. The web is transferred between 16a and 16b as the camera 18 rotates and as the capstan 16b is moving away from capstan 16a. As the web emerges from capstan assembly 16b, itpasses into the body of the rotating camera assembly through opening 21.

The web next proceeds through a curved web guide between walls 172 and 176 and into the camera re- .7 gion 180, as best seen am. 512. The path-length within the camera is such that as the leading edge of the web reaches a position opposite the aperture in aperture plate 31, mirror 33 attached to camera .18 is in 7 rotation are such that each revolution of the camera results in the recording on the film of a picture of anarrow band of terrain extending from oneedge to the other of the long dimension of the film. Accordingly, after n camera revolutions, n film strips have been recorded each strip of a different narrow sector of the terrain the aircraft has passed over (there may be some overlap). These strips, after'being developed, then may be placed edge-to-ed ge (the 48' edges abutting or slightly overlapping one another) to build up a two dimensional map of the terrain passed over by the aircraft. I

The actual-path taken by the film after exposure most easily may be seen in FIG. b. The exposed film .enters capstan assembly 16d and is driven thereby through curved web guide assembly184 to exit from the-camera 18 at opening 22. The web then traverses the space between the walls 162 and 164, FIG. 5a, and is engaged by capstan assembly 16c. The length of web 10, the travel distance within camera assembly 18 and the speed with which camera assembly 18 rotates are all interrelated in such a manner that as the web reaches caps tan assembly 160, that capstan assembly is just opposite capstan assembly 16a. As camera assembly 18 continues to rotate, the web emerging-from capstan assembly 16c will be contained between walls 166 and 204 as it is engaged and driven by capstan assembly l6e toward the capture mechanism 24.

While the description has been given in terms of a single elongated web 10, it will be seen from FlG. 1 that a series of webs one behind the other are continuously driven through the rotating camera assembly. While the invention has been described in the context of an aerial panoramic camera, it will be understood by those familiar with the art that the invention may be used in connection with any elongated strip of web material which it is desired to be pushed and/or pulled along a circuitous and complex path. 4

What is claimed is:

1. Means for transporting a web from a supply mechanism to a receiving mechanism moving relative to the supply mechanism comprising, in combination:

two parallel guide members, one attached to eachof said supply and receiving mechanisms, saidtwo members forming between them a web guiding 2. The combination as set forth in claim 1 wherein said guide members are curved and are moved relative to one another about a common. axis of rotation, said means for propelling said web into and. removing said 4 web from the space between said guide members being coupled to direct said web in a direction normal to said axis of rotation.

3. The combination as set forth in claim 2 wherein said coupled means are capstan drive means.

. 4. The combination as set forth in claim 1 wherein said guide members comprise porous material and further including means for supplying a gas to said porous material at a pressure elevated from that'of the environment in which said transporting means is placed.

5. in combination: v a stationary first guide member formed as an arc of a first circular cylinder; a movable second guide member formed as an arc of a second circular cylinder concentric withthe first and movable about their common axis, said two members forming between them a parallel-walled web guiding passage; means for propelling a web into said passage in the direction of movement of said second guide member; and 3 a means coupled to said second guide member for engaging said web and propelling it out of said passage.

6. The combination as set forth in claim 5 further including means for moving said movable guide members at a speed, X, relative to said stationary guide member;

and wherein said means propelling said web into said passage includes means for propelling said web into said passage with a speed,. Y, relative to said stationary guide member and said means propelling said web out of said passage includes means for propelling said web with a speed, Z, relative to said movable guide member, where Z Y X.

7. The combination as set forth in claim 5 further including means for moving said movable guide member at a speed, X, relative to said stationary guide member;

and wherein said means propelling said web into said passage includes means for propelling said web into said passage with a speed, Y, relative to said movable guide member and said means propelling said web out of said passage includes means for propelling it with a speed, Z, relative to said stationary guide member, where Z Y- X.

Claims (7)

1. Means for transporting a web from a supply mechanism to a receiving mechanism moving relative to the supply mechanism comprising, in combination: two parallel guide members, one attached to each of said supply and receiving mechanisms, said two members forming between them a web guiding passage; means for propelling a web into said passage in the direction of movement of said receiving mechanism; and means coupled to said receiving mechanism for engaging said web in said passage and propelling it out of said passage into said receiving mechanism.

2. The combination as set forth in claim 1 wherein said guide members are curved and are moved relative to one another about a common axis of rotation, said means for propelling said web into and removing said web from the space between said guide members being coupled to direct said web in a direction normal to said axis of rotation.

3. The combination as set forth in claim 2 wherein said coupled means are capstan drive means.

4. The combination as set forth in claim 1 wherein said guide members comprise porous material and further including means for supplying a gas to said porous material at a pressure elevated from that of the environment in which said transporting means is placed.

5. In combination: a stationary first guide member formed as an arc of a first circular cylinder; a movable second guide member formed as an arc of a second circular cylinder concentric with the first and movable about their common axis, said two members forming between them a parallel-walled web guiding passage; means for propelling a web into said passage in the direction of movement of said second guide member; and means coupled to said second guide member for engaging said web and propelling it out of said passage.

6. The combination as set forth in claim 5 further including means for moving said movable guide members at a speed, X, relative to said stationary guide member; and wherein said means propelling said web into said passage includes means for propelling said web into said passage with a speed, Y, relative to said stationary guide member and said means propelling said web out of said passage includes means for propelling said web with a speed, Z, relative to said movable guide member, where Z Y - X.

7. The combination as set forth in claim 5 further including means for moving said movable guide member at a speed, X, relative to said stationary guide member; and wherein said means propelling said web into said passage includes means for propelling said web into said passage with a speed, Y, relative to said movable guide member and said means propelling said web out of said passage includes means for propelling it with a speed, Z, relative to said stationary guide member, where Z Y - X.

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