An optical pantograph for directing light beams and the like from a source to a receiver according to the movement of a pointer. The device can be used for, among other things, directing a laser beam and the like to a target for etching patterns on a target according to the movement of a pointer relative to a pattern trace

Belew, Robert R.

Davis, Donald E.

NASA Technical Reports Server

United States Patent [191 
Belew et al. 
[ 1 1  1 3,936,942 
[451 Feb. 10, 1976 
[541 OPTICAL PANTOGRAPH 2,048,154 7/1936 Abbott et ai 
2,613,127 10/1952 Geiser ......... [75]  Inventors: Robert R. Belew, Huntsville, Ala.; 3,040,626 6/1962 
Donald E. Davis, Upton, Mass. 3,175,295 3/1965 
[ 731 Assignee: National Aeronautics and Space 3,244,893 4/1966 
3,528,424 9/1970 
3,776.1 13 12/1973 Parks et al 346/29 Administration Office of General Counsel-Code GP, Washington, 
Primary Examiner-Richard E. Aegerter 
Assistant Examiner-John W. Shepperd 
Attorney, Agent, or Firm-Wayland H. Riggins; L. D. 
Wofford, Jr.; John R. Manning 
............................ 
D.C. 
[22] Filed: Dec. 11, 1974 
(211 Appl. No.: 531,573 
................. ABSTRACT [52] U.S. CI. 33/24 R; 33/25 R; 346/108; [571 
354/4; 350/288 
[51 ]  Int.CL2 .......... .... ~ 4 3 ~  13/10; G02B 5/08 
35414; 2481476; 3501.288; 
33/23 R, 24, 25 
An Optical pantograph for directing light beams and 
[58]  Field of &arc .. 35612; 250/558; 3461108; the like from a Source to a receiver according to the 
movement of a pointer. The device can be used for, 
among other things, directing a laser beam and the 
like to a target for etching patterns on a target accord- 
ing to the movement of a pointer relative to a pattern 1561 References Cited 
1,662,830 3/1928 Lund 33/24 C 2 Claims, 3 Drawing Figures 
UNITED STATES PATENTS trace. 
.................................. 
1,914,258 6/1933 Howey ....................... 
https://ntrs.nasa.gov/search.jsp?R=20080012215 2019-08-30T03:58:36+00:00Z
U.S. Patent Feb. io, 1976 3,936,942 
3,936.942 
1 
OPTICAL PANTOGRAPH 
The invention described herein may be manufac- 
tured and used by or for the Government for govern- 
mental purposes without the payment of any royalties 
thereon or therefor. 
BACKGROUND OF THE INVENTION 
The present invention relates to an optical panto- 
graph and more particularly to a device for directing 
light beams such as laser beams, light waves emitted 
from the sun, and the like, to a receiver. Heretofore, 
devices have been developed for directing light beams 
according to predetermined patterns such as shown in 
U.S. Pat. No. 3,776,113 and U.S. Pat. No. 2,686,101. 
While these devices may operate satisfactorily for the 
purposes intended, it can be seen that such are fairly 
complicated, particularly the apparatus shown in U.S. 
Pat. No. 2,686,101 which is utilized for reproducing 
surface contours. In U.S. Pat. No. 3,776,113, a colli- 
mated light source is mechanically deflected in a carte- 
sian reference frame to record graphical data on photo- 
sensitive media. Conventional or high speed electro- 
mechanical plotting apparatus can be used to imple- 
ment the deflection. While this device may be satisfac- 
tory for plotting, it is not seen how such can be readily 
used for directing a light beam such as a laser beam to 
a receiver according to a predetermined pattern. 
SUMMARY OF THE INVENTION 
The invention includes an optical pantograph for 
directing light beams and the like from a source to a 
receiver according to a predetermined pattern or by 
continuously aligning the pointer optically with either a 
moving source or a moving receiver. The optical panto- 
graph includes a mirror with a first downwardly extend- 
ing leg attached thereto and a second downwardly 
extending leg spaced from said first leg pivotally at- 
tached thereto. A third downwardly extending leg is 
centrally disposed between the first and second leg and 
has an upper end attached to the mirror. A slidable 
joint is carried on a lower portion of the third down- 
wardly extending leg. Pivotal braces extend between 
the first and second legs and the slidable joint for main- 
taining the distance between the first leg and the third 
leg equal to the distance between the second leg and 
the third leg. By maintaining such distances equal, it 
can be seen that an angle defined by the first leg and 
2 
towards a desired target and to alter the target point 
according to the manipulation of the mechanism. 
Still another important object of the present inven- 
tion is to provide a simple and accurate device for 
5 controlling and manipulating a light beam according to 
predetermined patterns. 
Still another important object of the present inven- 
tion is to provide a device for directing a concentrated 
or unconcentrated energy source in a cullimated beam 
10 towards a desired target and to alter the sighting direc- 
tion to the energy source to continuously accommo- 
date a moving energy source, such as the sun. 
These and other objects and advantages of the inven- 
tion will become apparent upon reference to the fol- 
BRIEF DESCRIPTION OF THE DRAWING 
15 lowing specification, attendant claims, and drawing. 
FIG. 1 is a perspective view illustrating an optical 
pantograph constructed in accordance with the present 
FIG. 2 is a side elevational view of the optical panto- 
graph shown in FIG. 1. 
FIG. 3 is a fragmentary view showing a pointer modi- 
fied to provide for a sliding action along the line-of- 
25 sight direction of the movable leg which allows the 
pointer to adjust to surface irregularity in the trace 
pattern. 
DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring in more detail to FIG. 1 of the drawing, 
there is illustrated a light source generally designated 
by the reference character 10, which may be any suit- 
able light source such as a laser beam source. It is to be 
understood that the light source could be the sun, a 
35 picture produced by a projector, or any other similar 
device. The particular source 10 is provided for gener- 
ating a laser beam 12 which is directed towards a sub- 
stantially square shaped mirror 14 for being reflected 
back upwards to a receiver 16 in the form of a rectan- 
4 0  gular plate. Dotted lines 18, shown on the .plate, are 
provided to assimilate the path that the beam has trav- 
elled on the plate. If it is desired to etch a pattern on the 
receiver 16, such can be used to assimilate the etched 
pattern. 
The mirror surface 14 is supported on a cradle 20 
which has a pair of upwardly extending arms 22 and 24 
through which a pin 26 passes. 
A first downwardly extending leg 28 has its upper 
ends pivotally connected by pin 26 to the mirror 14. 
20 invention, and 
30 
45 
the third leg and the corresponding brace is always 50 Carried on a lower end of the first downwardly extend- 
equal to the angle defined by the . ~ c o n d  1% and the ing leg 28 is a pointer 30 which has a sharpened point 
third leg and the corresponding brace connected there- 32 on the lower end thereof which is used to follow the 
between. A pointer is carried on the lower end of the trace 34 on a pattern 36. The tip 32 of the pointer as 
first leg and such can be manipulated so as to trace a illustrated in FIG. 1 falls on an imaginary spherical 
pattern. The lower end of the second leg is rotatably 55 surface whose coordinate origin is at the intercept of 
secured to any suitable device SO as to Permit the the Z-axis and the upper surface of the mirror 14. The 
pointer to be able to follow a desired trace. As the first downwardly extending leg 28 includes a pair of 
pointer is moved, the slidable joint is raised and bw- spaced arms 38 and 40 which are positioned on oppo- 
ered on the third leg causing the mirror to deflect the site sides of the mirror 14 and have holes extending 
light beam impinging thereon to a different Portion of 60 through the upper ends for accommodating the pins 26. 
the receiver so that the light beam follows the trace The lower ends of the downwardly extending arms 38 
made by the pointer. and 40 converge towards the pointer 30 and are se- 
Accordingly, it is an important object of the present cured to an upper end thereof by any suitable means 
invention to provide an improved device for deflecting such as welding. 
light beams and the like. A second downwardly extending leg 42 is also pivot- 
Still another important object of the present inven- ally attached by its upper end to the mirror 14. The 
tion is to provide a device for directing a concentrated second downwardly extending leg 42 is defined by a 
or unconcentrated energy source in a collimated beam pair of spaced arms 44 and 46 which have holes extend- 
65 
maintain the first and second downwardly extending 
legs 28 and 42 an equal distance from the second rod 
60. 
As can be seen in FIG. 2, the triangle A defined by 
the brace 68, the upper portion of leg 28 and the por- 40 
tion of the rod 60 extending between pin 26 coupled to 
the mirror 14 and the pin 64 coupled to the sliding joint 
62 is equal to the triangle B provided by the brace 66, 
the upper portion of the second leg 42 between the pin 
70 and the pin 26, and the portion of the slidable rod 45 
between the pin 26 and the pin 64. These triangles A 
and B are always maintained equal as the pointer 30 is 
moved along a trace on the pattern 36. As the pointer 
moves outwardly, the slidable joint 62 slides upwardly 
on the rod 60. 50 
In operation, as the pointer is moved about the trace 
34 carried on the pattern 36, the rod 60 will rotate so 
as to always bisect the angle between the legs 28 and 
42. The slidable joint 62 slides up and down on the rod 
60 as it rotates. Since the rod 60 is connected to the 5 5  
mirror 14, the mirror will tilt as the rod rotates chang- 
ing the location of the reflected beam on the receiver. 
Thus, if it is desired to use a laser beam from the source 
10 to etch a pattern on a receiver 16, it is only neces- 
sary to put a corresponding pattern on a pattern trace 60 
36 and trace out the pattern by moving the pointer 30 
therealong. The beam 12 will follow the pattern traced 
and, in turn, be reflected on to the receiver to etch a 
corresponding pattern on the receiver. 
able joint 54 only being allowed to rotate about the Z 
axis, such can be changed so as to allow the second arm 
42 to slide up and down within the joint 54 so as to 
In one particular embodiment, instead of the rotat- 65 
3,93 6,942 
3 4 
ing through the upper ends thereof for accommodating permit the pointer to be moved off a given horizontal 
the pins 26. The lower ends of the second downwardly plane in order to trace contoured surfaces. Such would 
extending leg 42 converge toward a pivot joint 48 and require the mounting of the block 48 on a rod so that it 
are secured thereto by any suitable means such as weld- would operate similar to the slidable joint 62. 
ing. The pivot joint 48 includes a block 50 through 5 The pointer 30 may be modified as shown in FIG. 3 
which a bolt 52 extends so as to permit the second to slide longitudinally to accommodate irregular or 
downwardly extending arm 42 to rotate along an axis Z. imperfect trace patterns. Such a pointer would include 
The bolt 52 isjournaled within a housing 54 which is, in a shank portion 74 carried on a lower end of legs 28 
turn, secured to any fixed member such as illustrated and 40. A tubular pointer 76 is carried on the shank 
by the reference character 56. A nut 58 is carried on 10 portion 74 with a spring 78 provided on the shank 
the upper end of the bolt 52 for preventing the second portion 74 for forcing the pointer away from the collar 
leg 42 from slipping off of the bolt. 80. 
Disposed intermediate the first and second down- Therefore, the pointer 76 is permitted to slide up and 
wardly extending legs 28 and 42 is a third downwardly down on the shank portion 74 as it is moved over irreg- 
extending leg 60 which is in the shape of a rod that has 15 ular surfaces. 
its upper end secured to the member 20 which supports The optical pantograph is not necessarily limited in 
the mirror so that any movement of the rod causes the size to a small device. Large reflectors several feet in 
mirror 14 to move accordingly. diameter could conceivably be incorporated in a 
A slidable joint 62 having a longitudinal bore extend- scaled-up version to reflect solar rays on a target. A 
ing therethrough is provided for slipping over the rod 20 multiplicity of these reflectors geometrically arrayed 
60 so that the rod can move freely up and down with respect to a common collector would form the 
therein. The slidable joint 62 is in the form of a block basis for a solar heater for power conversion to steam 
and has pins 64 extending out opposite sides thereof for and then ultimately to electricity. For each such reflec- 
permitting pivotal braces 66 and 68 to be pivotally tor assembly, the leg 42 would be aligned with the 
attached thereto. The upper ends of braces 66 and 68 25 receiver while leg 28 would be maintained in alignment 
are connected between the legs 28 and 42 accordingly. with the sun during sunlight hours. 
For example, the brace 66 is pivotally connected be- While a preferred embodiment of the invention has 
tween the downwardly extending arms 44 and 46 of the been described using specific terms, such description is 
second leg 42 by means of pins 70. Similarly, the brace for illustrative purposes only, and it is to be understood 
68 is connected between the downwardly extending 30 that changes and variations may be made without de- 
arms 38 and 40 of the first leg by means of pins 72. The parting from the spirit or scope of the following claims. 
lower ends of the braces 66 and 68 include a pair of What is claimed is: 
spaced arms through which the pins 64 extend for piv- 1. An optical pantograph for directing light beams 
otally attaching such to the slidable block 62. The and the like from a source to a receiver according to a 
length of the braces 66 and 68 are identical so as to 35 predetermined pattern, said pantograph comprising: 
a first downwardly extending leg; 
a mirror; 
means for pivotally attaching an upper end of said 
first downwardly extending leg to said mirror with 
said first leg extending downwardly along a first 
longitudinal axis; 
a pointer carried on the lower end of said first leg; 
a second downwardly extending leg; 
means for pivotally attaching an upper end of said 
second downwardly extending leg to said mirror 
with said second leg extending downwardly along a 
second longitudinal axis at an angle to said first 
axis; 
means for focusing collimated light beams along one 
of said axes to said mirror for reflection from said 
mirror; 
means for receiving said light beams reflected from 
said mirror, said receiving means being located on ,  
the other of said axes; I 
a third downwardly extending leg centrally disposed ' 
between said first and second legs and having an 
upper end attached to said mirror; 
a slidable joint; 
a lower portion of said third leg extending through 
said slidable joint; 
a pivotal brace means carried between said first and 
second legs and said slidable joint for maintaining 
the distance between said first leg and said third leg 
equal to the distance between said second leg and 
said third leg; 
means for rotatably securing said second leg on a 
horizontal plane for rotation only about said sec- 
ond axis so that said first leg moves relative to said 
3,9 3 6,942 
5 6 
second leg as said pointer is moved about said 
pattern; 
whereby a light beam reflected from said mirror to 
said receiver is angularly reflected according to the 
angular movement of said first leg relative to said 
second leg. 
2. The invention as defined in claim 1, including 
means for mounting said pointer in a yieldably retract- 
able attachment whereby said pointer may automati- 
cally adjust its longitudinal position as it is moved over 
irregular surfaces. 
* * * * *  
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Optical pantograph

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