Impact testing machine for imparting large impact forces on high velocity package

Johnson, C. E.

English

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
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REPLY TO 
ATTN OF: 
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At ten t ion :  M i s s  Winnie M, Morgan 
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SUBJECT: Announcement of NASA-Owned 
U,S, Pa ten t s  i n  STAR 
I n  accordance wi th  t h e  procedures contained i n  t h e  Code GP 
t o  Code US1 memorandum on t h i s  s u b j e c t ,  dated June 8, 1970, 
the  a t t ached  NASA-owned U.S. p a t e n t  i s  being forwarded f o r  
a b s t r a c t i n g  and announcement i n  NASA STAR, 
The fol lowing information i s  provided: 
U.S .  Pa t en t  No. 
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Please note  t h a t  t h i s  patent covers  an  invent ion  made by an 
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https://ntrs.nasa.gov/search.jsp?R=19710013749 2020-03-17T03:02:21+00:00Z
OV . JAMES E. WEBB 
ADMINISTRATOR OF THE N A T I O N A L  
A E R O N A U T I C S  A N D  SPACE 
ADMI N I S T R A T I O N  
Filed Dec. 23, 1965 
IMPACT TESTING MACHINE 
f '" 
2 
INVENTOR. 
h E. J ~ ~ ~ S O  
3,412,595 
PACT TESTING MACHINE 
James E. Webb, Administrator of the hTatisnal Aero- 
nautics and Space Administration with respect to an in- 
vention of Carl Edward Johnson, Arfingtob, Va. 
Filed Dee. 23, 1965, Ser. No. 516,152 
1 Claim. (Cl. 73-12) 
ACT OF TWE DISCLOSURE 
A pair of bow limbs are-positioned on either side of a 
track and a bow line attached to the outer ends of the 
limbs is attached to a carriage which rides on the track 
for carrying a test package. A source of power draws the 
bow line against the bias of the bow limbs and a quick 
release mechanism release the power source from the bow 
so that the carriage and package are propelled at high 
velocity toward an impact receiving surface. A stop halts 
movement of the carriage shorf of the impact receiving 
surface and the package continues in free flight to impact 
the surface. 
Origin of the invention 
The invention described herein was made in the per- 
formance of work under a NASA contract and is subject 
to the provisions of Section 305 of the National Aero- 
nautics and Space Act of 1958, Public Law 85-568 (72. 
Stat. 435; 42 USC 2457). 
This invention relates to an impact testing device. 
More particularly this invention relates to an impact 
testing device which is compact and yet has the capability 
of imparting large impact forces on packages that have 
been accelerated to high velocities. 
In many fields there is a need for impact test machines. 
In the field of aerospace engineering, interplanetary mis- 
sion studies have shown that a need will exist for an im- 
pact test machine capable of simulating spacecraft 
planetary hard landings. When a spacecraft lands on a 
planet to perform subsequent experiments, it is necessary 
that the scientific payload be capable of withstanding 
the impact environment. In particular, if the space- 
craft impacts the surface with a relatively high velocity, 
the scientific payload must be isolated in some manner to 
insure successful mission performance. The design of the 
spacecraft structure and scientific experiments is very 
difficult and is advancing the state of the art. Therefore, 
it is necessary that tests be performed to collaborate 
analytical techniques and qualify designs. In performing 
these tests, the conditions of planetary hard landing 
(velocity, impact angle, planetary surface characteristics) 
should be simulated as closely as possible. 
Impact testing in prior art examples has failed to ade- 
quately fulfill the conditions of accurately simulating the 
impact of devices on the earth or other planetary bodies. 
One method in the past of testing impact on a package 
has been to drop the package from a building or the like. 
However, the impact is limited by the height to which 
the object is taken prior to drop and also the maximum 
terminal velocity an object can reach. Another method 
in the prior art by which impact can be transmitted to a 
device for measurment thereof is described in U.S. Patent 
No. 2,200,028 in which an inclined slide is used with a 
vehicle rolling thereon so that velocity is obtained and 
the impact can be measured at the bottom of the inclined 
slide. However, this device relies on gravity and of neces- 
sity occupies a great amount of space. 
This invention obviates many of the problems en- 
countered in the prior art examples by providing an impaa 
testing device which occupies relatively little space while 
imparting high velocity to a package to be tested. Also, 
5 
10 
15 
20 
25 
30 
35 
40 
the test package is not overly constrained with respect to 
size. The device in its briefest aspects consists of a track 
along which the package to be tested is guided, with a pair 
of bow limbs on either side of the track to which i s  
attached a bow line, A carriage in which the package is 
carried, is attached to the bow line. A source of power, 
such as an electrical winch, draws the bow line against 
the bias of the bow limbs. A quick release mechanism, 
when actuated releases the power source from the bow line 
so that the carriage is propelled toward an impact receiv- 
ing surface. The package is hurled a,t high velocity against 
the impact receiving surface, 
It is t h e r e h e  an object of this invention to provide 
an improved impact testing device, 
Another object of this invention is to provide an im- 
proved method of testing impact on packages or the like. 
Other and more particular objects of this invention 
will become apparent as this description proceeds. 
The drawing is a perspective view of the impact testing 
device according to this invention. 
In the drawing, package 2 represents an object which 
is to be subjected to impact testing, and may consi8t of a 
scientific payload subsystem or an overall system on 
which it is desired to learn what effect impacit has. A 
carriage 4 is guided along a guide track 6 and functions 
to hold the package 2, adapt it to the bow line 14 and 14, 
and to propel package 2 toward an impact receiving sur- 
face 8. This impact receiving surface can be varied by 
applying a variety of surfaces thereon to simulate any 
desired conditions. In addition, this surface may have vary- 
ing shapes, and angle entries can be simulated by rotating 
surface 8 about pivot point 10. A damper or stop member 
12 is provided close to the impact receiving surface 8 so 
that carriage 4 can be stopped to allow package 2 to 
be impacted against surface 8 in free flight without in- 
terference by carriage 4. Carriage 4 is releasably con- 
nected to bow line 14 and 16 each of which is attached 
at the other end thereof to bow members 18 and 20 
respectively. These bow members can be comprised of a 
homogeneous, laminated, or sandwich construction to 
apply the bias to lines 14 and 16. Also, the bow limbs 
can be preloaded to yield a more efficient machine. It is 
preferable that in the unbiased position, bow members 
18 and 20 are curved. with a constant radius of curvature, 
45 and when held back assume a straight position. The con- 
cave side of the unbiased bow limb faces generally for- 
wardly toward the impact receiving surface. It is also 
preferable that the bow members 18 and 20 have a con- 
stant thickness and when in the straight position, the width 
50 vary as an isosceles triangle. That is, the outer free end 
of the limb forms the approximate apex of the triangle, 
the inner fixed end forms the base of the triangle, and the 
upper and lower edges of the limb form the equal sides 
of the triangle. These bow members are anchored in solid 
55 masses such as concrete pillars 22 and 24 as shown in the 
drawing. A bracing struature designated generally as 26 
is utilized to help stablize the pillars. 
Carriage 4 has associated therewith a quick release 
mechanism such as illustrated generally as 28 and may 
60 comprise any conventional quick release mechanism. For 
example, a quick release mechanism such as shown in 
U.S. Patent to Colby, No. 1,866,926 can be utilized. In 
any event the quick release mechanism forms no part of 
this invention. One end of cable or like device 30 is at- 
65 tached to the quick release mechanism, and the other end 
is connected with a winch or the like powered by any 
convenient motor source mounted within housing 32. Bow 
members 18 and 20 are attached to pillars 22 and 24 
respectively in such a manner that they may be removed 
70 readily and different bow members substituted therefor. 
The surface of track or guide 4 can be coated with suitable 
substances to provide varying friction resistance. For ex- 
3,412,598 
ample, these substances may se ice or Teflon or any 
other suitable material. In addition, guide or track mem- 
ber 5 can be elevated or lowered to accommodate different 
package 2 is placed in position on carriage 
e 30 winched to pull bow lines 14 and 16 
s of bow arms 18 and 20 toward housing 
32. When a desired bias has been attained, the quick 
release mechanism 28 is activated to release cable 30 from 
carriage 4. The package and carnage will then be hurled 
at high velocity toward impact receiving surface 8. As 
the carriage strikes damper or stop member 12, the car- 
ed and the package 2 hurled against the 
the package impacts against the impact 
in free flight simulating real conditions. 
Thus it can be seen that by this invention there has 
been provided a relatively simple, compact and efficient 
mechanism which is capable of imparting a high velocity 
and free flight to a test package within a relatively short 
distance, and which is capable of accommodating test 
pacages of a variety of sizes. 
Having described this invention, it is to be understood 
that it is to be limited only by the scope of the claim 
appended hereto. 
is claimed is: 
device for measuring impact stresses on a package 
which comprises: 
biasing means adapted to project a package toward 
said surface, said biasing means comprising two bow 
limbs located opposite each other on opposite sides 
of said track, a carriage movably mounted on said 
track, said carriage being adapted to hold and propel 
a package, a bow string attached to said carriage and 
said carriage and said bow limbs; 
a power source adapted to draw said bow string, car- 
riage and package against the bias of said bow limbs; 
a quick release connecting said bow string and said 
whereby release of said quick release means will allow 
said carriage and said package to be accelerated 
toward said impact receiving surface along said track; 
and 
stop means to halt movement of said carriage short of 
said impact receiving surface. 
Io power source; 
eferences Cited 
20 UNITED STATES PATENTS 
2,185,091 12/1939 Orlando et al. _ _ _ _ _  124-25 X 
2,526,369 10/1950 Kiesel Horst _ _ _ _ _ _ _ _ _  124-23 
2,740,286 4/1956 DeVost et al. _ _ _ _ _ _ _ _ _  73-12 
25 2,894,503 7/1959 Pierson et al. _ _ _ _ _ _  124-24 X 
RICHARD C. QUEISSER, Primary Examiner. 
JAMES H. WILLIAMSON, Assistant Examiner. an impact receiving surface; a track adapted to direct a moving structure thereon 
toward said surface; 


Impact testing machine Patent

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