Manual control mechanism for adjusting control rod to null positio

Newcomb, J. F.

English

NASA Technical Reports Server

REPLY TO 
ATTN OF: GP 
NATIONAL AERONAUTICS AND SPACE ADM INISTRATION 
WASHINGTON, D.C. 20546 
TO 2 USI/Scientific & Technical Information Division 
Attention: Miss Winnie M e  Morgan 
GP/Office of Assistant General 
Counsel for Patent Matters 
SUBJECT: Announcement of NASA-Owned 
U,S, Patents in STAR 
In accordance with the procedures contained in the Code GP 
to Code US1 memorandum on this subject, dated June 8, 1970, 
the attached NASA-owned U , S ,  patent is being forwarded for 
abstracting and announcement in NASA STAR, 
The following information is provided: 
U , S .  Patent No. 
Corporate Source 
Supplementary 
Corporate Source 
NASA Patent Case No.: -01808 
/ 
GayBe Parker 
- 
=! 2 (NASA CR OR TMX OR AD NUMBER) 
Y 
I 
(CATEGORY) 
NASA-HQ 
https://ntrs.nasa.gov/search.jsp?R=19710011265 2020-03-17T02:53:42+00:00Z
Jan. 23, 1968 J. F. NEWCOMB 
NULL DEVICE FOR HAND CONTROLLER 
Filed Dec. 28, 1965 2 Sheets-Sheet 1 
\ J v 
INVENTOR 
ATTORNEYS 
BY 
Jan. 23, 1968 J.  F. NEWCOMB 
NULL D E V I C E  FOR HAND CONTROLLER 
Filed Dec. 28, 1965 2 Sheets-Sheet'% 
44 
52 
82 
62 
40 
FIG. 
BY 
50 
57 
L , : I  
ATTORNEYS 
3,364,777 
.bhn P. Newcomb, Gloucester Point, Va., aSSignQr to the 
United States of America as ~ ~ ~ ~ e s e ~ ~ e ~  by the Ad- 
r n ~ n ~ s ~ ~ ~ Q r  of the National Aeronautics and Space 
A ~ ~ ~ ~ i s ~ a ~ o ~  
RBed Dec. 28,1965, Ser. No. 517,159 
11 Claims. (el. 74-478) 
ACT OF THE DISCLOSURE 
A device for producing an accurate null position in a 
spring-centered member, consisting of positively limiting 
opposing movement of the spring members with respect 
to a reference structure. The reference structure is also 
adjustable with respect to a support to provide adjustabil- 
ity of the null position. 
The invention described herein was made by an em- 
ployee of the United States Government and may be man- 
ufactured and used by or for the Government for gov- 
ernmental purposes without the payment of any royalties 
thereon or therefor. 
This invention relates generally to a hand controller 
and more particularly to a mechanism for precisely re- 
turning a control rod to a null or neutral position. 
In recent years there has been an increasing need for 
miniature three-axis controllers to be ernp!oyed in various 
control systems such for example as those of aerospace ve- 
hicles. The previously known controllers utilized a gimble 
system and a gear-electrical pickoff for each control mo- 
tion. These previous systems failed to provide for the con- 
trols to be returned precisely to zero and the original zero 
or null position of the control rod could not be accurately 
adjusted. The neutral positioning devices developed by the 
prior art similarly failed to provide for accurate adjust- 
ment or precise return to zero and, further, are generally 
large and cumbersome and undesirable for use where space 
is a critical requirement. These devices normally intro- 
duce high frictional forces or require exact mating of 
springs to accurately position the lever or controller in 
the neutral position. Such assemblies become even more 
unreliable after extended use due to the unsymmetrical 
fatigue of the springs. Devices such as these are wholly 
inadequate for reliable operation in the extremely limited 
spaces. 
In order to overcome the disadvantages of the prior 
art, the instant invention contemplates the use of a 
locator mechanism for accurately adjusting the neutral po- 
sition and opposed resilient members for precise return 
of the controller to the neutral position. 
It is an object of the instant invention to provide a 
control mechanism which returns precisely to a null posi- 
tion. 
A further object of this invention is to provide a mech- 
anism for accurately adjusting the neutral position of a 
controller. 
Another object of the instant invention is to provide 
a controller wherein the control rod is returned precisely 
to the original zero position which may be accurately ad- 
justed. 
Still another object of this invention is to provide a 
locator mechanism for accurately adjusting the neutral po- 
sition of a controller and a positioning mechanism for 
precisely returning the controller to that neutral position. 
A still further object of the instant invention is to pro- 
vide a locator mechanism for accurately adjusting the 
null position of a control rod while utilizing a pair of op- 
positely disposed resilient arcuate members for precise 
return of the control rod to that null position when the 
control force is removed. 
Generally, the foregoing and other objects are accom- 
plished by utilizing pivoted members attached to a mount 
and a base plate with a thumbscrew extending between 
the pivoted flanges such that slight rotation of the thumb- 
5 screw causes slight lateral movement of the base plate. 
Opposed arcuate resilient members mounted on the base 
plate with a stop centered thereon for preventing unsym- 
metrical movement of the resilient members. The control 
rod is pivoted about the same point as the base plate and 
is provided with a rider element that acts against the re- 
silient members when a control force is applied. 
A more complete appreciation of the invention and 
many of the attendant advantages thereof will be readily 
apparent as the same becomes better understood by refer. 
15 ence to the following description when considered in con- 
nection with the accompanying drawings, wherein: 
FIG. 1 is a schematic general plan view of a three- 
axis controller of the prior art; 
FIG. 2 is basically a rear elevation view of the novel 
20 null device of the instant invention; 
FIG. 3 is an elevational view of the null device of 
FIG. 4 shows the instant invention as applied to the 
FIG. 5 is a detailed view of a portion of FIG. 2. 
Referring now to the drawings and more particularly 
to FIG. 1 wherein a three-axis hand controller 10 is shown 
to include mechanisms for control about the X, Y, and Z 
axes. Control rod 12 is shown in end view and controls 
30 gears 14, 16 and 18 through a conventional universal 
joint, not shown. Gears 14, 16 and 18 rotate with the con- 
trols and engage cog wheels 20, 22 and 24 which in turn 
rotate sensors, not shown, in potentiometers 26, 28 and 
30. Gimbal rods 32, 34, and 36 act to support and permit 
35 rotation of gears 14, 16 and 18, respectively. The above 
described controllers and others like it are typical of the 
prior art. 
Referring now to FIGS. 2 and 3 wherein the instant 
inventive null device is shown to include sensing rod 40, 
40 which may be equated to hand controller 12, suspended 
from a support, shown as a framework mount 42. Brackets 
44 are rigidly fixed to framework 42 and have pin 46 ex- 
tending therebetween. Sensing rod 40 has rider 48 rigidly 
affixed thereto and centered for a purpose to be described 
more fully hereinafter. 
Base plate 50 is substantially pie-shaped and flat having 
an aperture 52 near the point thereof for permitting piv- 
otal movement of plate 50 about pin 46. Stop 54 is cen- 
trally located adjacent, but spaced from the arcuate edge 
of plate 50 and extends therefrom in the direction of sens- 
50 ing rod 40. A pair of arcuate tubular guides 54 and 57 
are secured to plate 50 along the arcuate edge thereof and 
respectively have closures 58 and 59 for closing the outer 
ends thereof along the straight edges of plate 5%. A pair 
of retainer opposed springs 60 and 61 are respectively dis- 
55 posed in guides 56 and 57 and abut closures 58 and 59 
thereof. A pair of arcuate plungers 62 and 63 have a 
portion within and a portion extending from guides 56 
and 57. Plungers 62 and 43 abut stop 54 thereby positively 
limiting the movement of these members toward each 
other in opposition to each other. Stop 54 and rider 48 
are centrally alined when sensing rod 40 is in the null 
position. 
Locator mechanism 70 includes mount flange 72 which 
65 is rigidly secured to framework 42 and hinge leaf 74 hav- 
ing threaded bore 76 extending therethrough. Mount 
flange 72 and hinge leaf 74 are pivotally mated by pin 
78. Plate flange 88 is pivotally mounted on plate 50 by 
pin $2 which extends from plate 50 in a direction opposite 
70 to that of stop 54. Flange 80 is provided with bore 84 
for receiving thumbscrew 90. 
FIG. 2 taken in the direction of line 3-3; 
prior art device of FIG. 1; 
25 
45 
3,364,777 
Thumbscrew 90 includes shank 92 having enlargement 
94 at one end thereof. Threads 96 on shank 92 are adja- 
cent enlargement 94 and engage threaded aperture 76. As 
best seen in FIG. 5, adjacent the other end of shank 92 is 
annular groove or slot 98 which is positioned to be in 
proximity to flange 80. Retaining plates PO0 are mounted 
on plate flange 80 by screws 102 to fit within slot or groove 
98 in shank 92 and thus cause movement of plate flange 
80 upon rotation of enlargement 94 of thumbscrew 90. 
FIG. 4 shows the instant invention installed on one of 
the three axes of a controller such as that shown in 
FIG. 1. The null positioning device is installed on gear 
14 which allows movement about the Z axis. Guides 56 
and 57 are mounted on plate 58 which pivots about gimbal 
rod 32 while rider 48 is secured to gear 14, which is now 
the motion sensor. In this assembly, locator mechanism 
70 is mounted behind the pivot point which would be the 
center of gimbal rod 32. Gimbal rod 32 thereby being 
equivalent to pivot pin 46 shown in FIG. 2. Obviously, the 
device would be mounted upon the other two axes of the 
three-axis controller of FIG. 1. 
Operation 
The pilot, either directly or by a linkage (not shown), 
moves control rod 40 to the right, FIG. 2, rotating the 
bottom of rod or sensor 40 to the left. Plunger rider 48 
picks up plunger 62 and drives it back into guide 56 there- 
by compressing spring 60. At the point of maximum dis- 
placement of sensing rod 40 the face of plunger 62 is flush 
with the open end of tubular guide 56 and therefore 
plunger rider 48 comes to a definite stop when it rests 
against the €ace of guide 56. Plunger 63 is not displaced 
since it is resting against plunger stop 54. When the pilot 
releases pressure on controller 40, compressed spring 60 
forces plunger 62, and in turn control rod or sensor 40, 
back to the original zero or neutral position. Once sensor 
40 is back in the null position, plunger rider 48 is trapped 
between plungers 62 and 63 which always must stop at the 
same position because of plunger stop 54. 
When the pilot moves the control rod 40 to the left the 
lower end of rider sensor 40 moves to the right, FIG. 2. 
This movement causes plunger rider 48 to press against 
plunger 63 forcing it into guide 57 and compressing spring 
61. Plunger 62 remains in the original position as it is 
still resting against plunger stop 54. When the control 
force is released, rod 40 returns to the null position and 
remains there in a manner similar to that described for 
control movement to the right. 
In the process of altering the zero or null position of 
control rod 40, thumbscrew 90 is rotated and threads 96 
on shank 92 engage threaded bore 76 in leaf 74, thus 
moving thumbscrew 90 in or out of leaf 74. The end of 
thumbscrew 90 is retained in plate flange 80 by retainers 
BO0 in such a manner that it can rotate but cannot move 
laterally therethrough. Thus, when thumbscrew 90 is ro- 
tated so as to screw into leaf 74, the total assembly on 
base plate 50 and control arm 40 will rotate to the right 
about pivot pin 46. Thumbscrew 90 is simply rotated in 
the opposite direction to rotate plate 50 and sensing rod 
40 to the left. It is to be noted that leaf 74 and flange 80 
are pivoted about pins 78 and 82, respectively, so as to 
form hinges. This arrangement permits thumbscrew 90 to 
follow the motion of plate 50. 
From the foregoing description and explanation, it is 
readily apparent that springs 60 and 61 need not be 
matched but only be strong enough to return arm 40 to 
the null position and retain it there until pressure is again 
applied to control rod 48. In various ciroumstances, 
modifications may be made to the device as shown, for 
example, tubes 56 and 57 could be straight rather than 
arcuate. Such a construction might facilitate manufactur- 
ing but would introduce high friction between plunger 
rider 48 and plungers 62 and 63 as control rod 40 is 
moved. Thus it is seen that the instant invention provides 
an extremely accurate method of retaining the null posi- 
5 
10 
15 
20 
25 
30 
35 
4 
tion of a controller as well as a simple, reliable and effec- 
tive method for that precise positioning. The simple and 
accurate positioning permits substantial miniaturization 
and the attendant utilization of the invention in restricted 
spaces. The instant device further provides the feature of 
easily and accurately adjusting the zero or neutral position. 
Obviously, many modifications and variations of the 
subject invention are possible in the light of the above 
teachings. It is therefore to be understood that within the 
scope of the appended claims the invention may be 
practiced otherwise than as specifically described. 
What is claimed as new and desired to be secured by 
Letters Patent of the United States is: 
1. In a null device for a hand controller the combina- 
tion comprising: a sensing member for sensing the move- 
ment of a controller member; a base plate; a support; 
locator means for positioning said base plate with respect 
to said support; rider means secured to said sensing mein- 
ber; opposed resilient means having respective portions 
engaging said rider means; stop means secured to said 
base plate positively limiting opposing movement of each 
of said respective portions relative said base plate, where- 
by said sensing member is accurately located with respect 
to said base plate and support. 
2. The null device combination of claim B wherein said 
locator means comprises means rotatably mounting said 
base plate on said support and, pivotal mount means 
drivingly connected to said support; pivotal plate means 
drivingly connected to said base plate; a thumbscrew; 
means drivingly connecting said thumbscrew, said pivotal 
mount means, and said pivotal plate means providing 
relative movement between said pivotal mount means and 
said pivotal plate means when said thumbscrew is rotated, 
whereby rotation of said thumbscrew effects a movement 
of said base plate with respect to said support to establish 
a null position for said sensing member. 
3. The null device combination of claim 1 wherein said 
opposed resilient means comprises: a pair of guide means 
mounted on said base plate; retainer spring means dis- 
40 posed in said guide means; and said respective portions 
comprise members disposed in said guide means and 
extending between said spring means and said rider means. 
4. The null device combination of claim 1 wherein said 
stop means comprises: a boss rigidly mounted on said 
base plate centrally of said resilient means. 
5. The null device combination of claim 4 wherein said 
rider means comprises: a projection on said sensing mem- 
ber, whereby said projection is disposed in alignment with 
said boss when said sensing means is in the null position. 
6. The null device combination of claim 5 wherein said 
50 locator means comprises: a mount flange rigidly attached 
to said support; a hinge leaf pivotally connected with said 
mount flange by a first pin; a plate flange pivotally at- 
tached to said base plate by a second pin; a threaded bore 
in said hinge leaf; an aperture of substantially the same 
55 size as said bore in said plate flange; retaining plates adjust- 
ably secured to said plate flange; a thumbscrew having a 
shank with an enlargement at one end thereof; said shank 
having a threaded section adjacent said enlargement; an 
annular groove spaced from the other end of said shank 
for receiving said retaining plates, whereby rotation of said 
thumbscrew effects slight movement of said base plate. 
7. The null device combination of claim 5 wherein said 
opposed resilient means comprises: a pair of oppositely 
65 disposed arcuate tubular guides attached to said base plate 
in a substantially spaced end-to-end relationship; said 
guides having closed outer ends; a spring disposed in each 
of said guides adjacent said closed end thereof; said re- 
spective portions comprise a plunger disposed in each of 
70 said guides in juxtaposition to said spring; a portion of 
each of said plungers extending beyond the end of said 
guides and having the end in abutting relation to said boss 
and said projection when said control rod is in the null 
45 
75 position. 
3,364,777 
8, The null device combination of claim 7 wherein said mounting said guide on sai ase plate in spaced, end-to- 
locator means comprises: a mount flange rigidly attached end relation with said rider means centrally disposed there- 
to said support; a hinge leaf pivotally connected with said between; spring means disposed in said guides; plunger 
mount flange by a first pin; a plate flange pivotally at- means disposed in said guides and extending between said 
tached to said base plate by a second pin; a threaded bore 5 spring means and said rider; a stop mounted on said base 
in said hinge leaf; an aperture of substantially the same plate disposed between said plunger means whereby said 
size as said bore in said plate flange; retaining plates ad- sensor rod is in alignment with said rider in the neutral 
justably secured to said plate flange; a thumbscrew having position. 
a shank with an enlaltgement at one end thereof; said 11. The combination of claim 10 further comprising: 
shank having a threaded section adjacent said enlarge- a mount flange rigidly attached to said support means; a 
ment; an annular groove spaced from the other end of said hinge leaf pivotally connected with said mount flange by 
shank for receiving said retaining plates to effect slight a first pin; a plate flange pivotally attached to said base 
movement of said base plate by rotation of said thumb- plate by a second pin; a threaded bore in said hinge leaf; 
screw to thereby locate said base plate in a null position an aperture of substantially the same size as said bore in 
with respect to said sensing member. 15 said plate flange; retaining plates adjustably secured to 
9. The null device of claim 8 comprising: said sensing said plate flange; a thumbscrew having a shank with an 
member including a gear thereon; said support including a enlargement at one end thereof; said shank having a 
gimbal rod; said gear and base plate pivotally mounted on threaded section adjacent said enlargement; an annular 
said gimbal rod; and said locator means mounted on said groove spaced from the other end of said shank for re- 
base plate on said opposite side of said rod from said 20 ceiving said retaining plates, whereby rotation of said 
thumbscrew effects slight movement of said base plate. 
. In a controIIer the combination comprising: sensing 
means including a sensor rod; a base plate; support means 
for said sensing means and base plate including a gimbal 
rod; means pivotally mounting said base plate on said gim- 25 FRED '* MAmERNy JR*, 
bal rod; a rider on said sensor rod; a pair of guides; means 
No references cited. 
Examiner- 
F. D. SHOEMAKER, Assistant Examiner. 


Null device for hand controller Patent

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