Carr, W. F.

English

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OFT. J A M E S  E. WEBB 
R OF THE N A T I O N A L  A E R O N  
A D M I N I S T R A T I O N  
SPLIT NUT SEPARATION SYSTEM 
Filed Oct. 26, 1966 2 Sheets-Sheet 1 
FIG. I 
10 
12 
https://ntrs.nasa.gov/search.jsp?R=19710012014 2020-03-17T02:49:31+00:00Z
JAMES E. WEBB 
A DM IN IS+ R OF THE NATIONAL AERQN 
SPACE ADMINISTRATION 
SPLlT NUT SEPARATION SYSTEM 
Filed Oct. 26, 1966 2 Sheets-Sheet 2 
INVENTOR. 
3,352,192 
J ro- 
an 
7 Claims. (CY. 85-33) 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-548 
(72 Stat. 435; 42 USC 4257'). 
This invention relates to an improved device for re- 
leasably securing adjoining sections of objects to each 
other, and for automatically separating them when 
desired. 
In the conduct of the present space exploration activity, 
it is usually desirable to jettison a rocket motor from its 
pay load after burn out. Also, in air launched sonabuoy 
systems two tandem connected cylindrical sections of 
sonabuoys ballistic casings are usually separated after im- 
mersion in the sea to form thereby an operational trans- 
mitter buoy and depending hydrofoam combination. It is 
desirable in either case, at the proper time to insure a 
prompt and certain separation. In the case of the outer 
space activity, it is desired not to fill the environment with 
debris or outgassing thus placing the requirement that 
none of the products or components which are broken in 
the separation leave either of the separating components. 
Accordingly, an object of this invention is the provision 
of a novel construction for a separation system which 
couples two devices. 
Yet another object of the present invention is the pro- 
vision of a separation system for coupling two devices 
which has a very high order of reliability when actuated. 
Still another object of the present invention is the pro- 
vision of a separation system construction which avoids 
both explosive outgassing and loose debris when actuated. 
These and other objects of the present invention may 
be achieved in an arrangement wherein the two parts 
which are joined together by the separation system are 
primarily held together by a bolt which is a part of the 
system, and is called a separation bolt. The bolt passes 
through two holes in the two components which are to 
be separably attached. The head end of the bolt holds 
one of the components and a split nut has threads therein, 
into which the threaded end of the bolt is screwed to  
hold the other component in proximity to the first com- 
ponent. In a space between the two components through 
whimch the separation bolt passes, there is provided a large 
spring which is in compression. This spring is called a 
separation spring and its function is to separate the two 
components and impart separation velocity when the 
separation bolt is no longer holding them together. A sec- 
ond compression spring termed a bolt ejection spring is 
attached to one of the components at one end and has 
its other end attached to the bolt. This spring throws the 
bolt in the direction of the bolt head when the split nut 
is separated and the bolt is let go. A cup covers the bolt 
and contains a mechanism to catch and hold the separa- 
tion bolt when it is ejected by the bolt ejection spring. 
The threaded portion of the bolt is held by a split nut, 
the two pieces of which are held together by a cross bolt. 
Two separation nuts are respectively mounted on the 
two halves of the split nut on opposite sides of the cross 
bolt. These may be actuated by an electrical signal which 
detonates an explosive within the separation nuts causing 
a plunger to move whereby the cross nut pieces are 
pushed apart to  release the threaded end of the separation 
bolt. The bolt ejection spring can then act to throw the 
separation bolt out into its catcher. The separation spring 
can then push the two objects or components apart from 
one another. A second debris container encloses the split 
nut and the two separation nuts and catches the debris 
The novel features that are considered characteristic 
of this invention are set forth with particularity in the ap- 
pended claims. The invention itself both as to its organiza- 
tion and method of operation, as well as additional objects 
and advantages thereof, will best be understood from the 
following description when read in connection with the 
accompanying drawings, in which: 
FIGURE 1 is a drawing of two portions of a hypo- 
thetical space vehicle which are releasably secured by a 
15 plurality of separation systems in accordance with this 
invention; and 
FIGURE 2 is an enlarged cross-sectional diagram 
showing a separation system in accordance with this in- 
vention; and 
FIGURE 3 is a firing schematic drawing for the separa- 
tion system. 
FIGURE 1 illustrates two adjoining portions of a space 
vehicle comprising for example a flight craft 10 and a 
launch vehicle 12. The two are held together by a plurality 
25 of separation devices, 14, 16, only two of which are in- 
dicated. However, it will be appreciated that a plurality of 
these separation devices are required spaced around the 
adjoining perimeters of the two components to be sep- 
arated. 
FIGURE 2 is an enlarged view in cross-section of one 
of the separation devices 14, 16, shown in FIGURE 1.  
The system includes a separation bolt 20, h a v i p  a bolt 
head 22 at one end, and a threaded portion 24 at the 
other end. The separation bolt fits through two holes in 
35 the respective flight craft and launch vehicle perimeter. 
It holds these two objects together by being threaded into 
a split nut 28 the two halves of which respectively 30, 3% 
are held together by a cross bolt 34. 
Mounted on the respective split nut halves 30, 32 are 
40 two separation nuts, respectively 36, 38. By way of ex- 
ample, these may be of the type known as the 7300 series, 
manufactured by Hi-Shear Corporation, of Torrance, 
Calif. These are preferably nonfragmenting and non-out- 
gassing. This type, while preferable, is not to be construed 
45 as a limitation upon the invention since any separation 
nut may be employed here which is nonfragmenting 
and non-outgassing. The separation nut, and split nut 
assembly are all contained within a debris catcher con- 
tainer 40, which is attached to the launch vehicle and 
50 which prevents debris from being scattered upon separa- 
tion. 
In a space between the launch vehicle and the flight 
craft, through which the shank of the separation bolt 
passes, there are placed two compression springs. One of 
55 these which may be termed the separation spring 42, is 
held in compression between the two objects to be sepa- 
rated, and serves to push them apart when the separation 
bolt is released. The second spring 44, is termed a bolt 
ejection spring. This spring is compressed between the 
60 launch vehicle and a disc 46 attached by any suitable 
means to the shank of the separation bolt. A spring retainer 
48, which is attached by a screw 50 to the launch vehicle 
adapter serves to hold one end of both springs to prevent 
them from being lost when the two portions separate. 
FIGURE 3 is a firing schematic drawing for the separa- 
tion system in accordance with this invention. On the 
assumption that four separation systems are used to 
separably attach two bodies, there are shown schematically 
eight separation nuts respectively 54, 56, 58, 60, 62, 64, 
70 66, 68 which would be used. Two separation nuts are used 
for each separation system as shown in FIGURE 2. Each 
separation nut pair, 54, 56, has four bridge wires 70, 72, 
5 therefrom. 
20 
30 
65 
3,352,192 
74, 76, for example, electrical current through any one of 
which causes a detonation of a power cartridge not shown 
which separates the split nut halves. To insure separation, 
all the upper bridge wires, 70, 74 are connected in 
parallel to one power supply 78, which is in series with a 
switch 78. All the lower bridge wires are connected to 
another power supply 80, in series with a switch 84. The 
switches are usually remotely controlled. 
The electrical system described insures that upon the 
dosing of at least one switch, a t  least one of the bridge 
wires in a separation nut will receive current and will 
fire a cartridge which generates gas pressures within the 
separation nut which (referring to FIGURE 2), releases 
the cross bolt 34 in the split nut. A pressure plunger, also 
within the separation nut, is also released at this time 15 
which serves to drive the split nut apart. As a result, the 
separation bolt is released and under the force of the bolt 
ejection spring 44, is thrown upward into a bolt catcher 
CUD 52, which is attached to  the flight craft over the open- 
5 
included bolt ejection compression spring means com- 
pressed between one of said objects and said separation 
bolt for ejecting said bolt when said split nut halves are 
separated. 
4. Apparatus as recited in claim 1 wherein there is 
included debris container means attached to said one of 
said objects and enclosing therein said separation nut 
means and said split nut. 
5. Apparatus as recited in claim 3 wherein there is 
included bolt catcher container means for catching said 
bolt when it is ejected by said bolt ejection spring means. 
6. Apparatus for releasably holding together two ob- 
jects comprising a separation bolt having a thread on one 
end, holes in said two objects for enabling said bolt to 
be passed therethrough, split nut means including two nut 
halves having threads in opposite faces thereof for engag- 
ing the threads on the end of said separation bolt for 
holding said two objects together, cross bolt means thread- 
ably engaging said two split nut halves for holding them 
ing of ‘the bolt. The debris caused by the detonation of 20 together for retaining the threaded end of said separation 
the separation nuts is caught in the debris catcher 40. bolt, separation nut means mounted on said split nut for 
Under the urging of the separation spring 42, the two forcing said split nut halves apart when actuated, a con- 
portions of the space vehicle are separated from one an- tainer, means for supporting said container for enclosing 
other at a velocity which can be established by the spring said separation nut means and said split nut, separation 
constants of the separation spring. The separation spring 25 spring means mounted between said two objects for 
and bolt ejection spring are both retained by the spring separating said two objects when said separation bolt is 
retainer. 1 ejected, bolt ejection spring means mounted for rejecting 
From the foregoing explanation it should be apparent said separation bolt when said split nut is separated into 
that there has been descrbied and shown herein a novel, two parts, and bolt catcher container means mounted over 
useful and reliable separation system for separably attach- 30 the head end of said bolt for catching said bolt when it is 
ing two objects. ejected. I 
What is claimed is: 7. Apparatus as recited in claim 6 wherein there is 
1. A separation system for attaching two objects to- included means for retaining one end of said separation 
gether in a manner so that they can be separated com- s p h g  means and said bolt ejection spring means attached 
prising a separation bolt having a thread at one end, 35 to one of said objects. 
opening in said objects through which said bolt passes, 
a split nut comprising two halves having threads in op- eferences Cited 
posite faces of said two halves for engaging the threads 
on said bolt, cross bolt means holding said two halves 2,421,807 6/1947 Richey et al. 
together, said separation bolt being threaded into the 40 
threads of said split nut for holding said two objects to- 2,871,750 2,1959 Parfish. 
gether, compression spring means for yieldably biasing 2,937,595 5/1960 Margulis et al. 
said two objects apart against the restraining force of said 2,984,J44 5/1961 Erdmann _ _ _ _ _ _ _ _ _ _ _ _ _  85--33 
halves against the retaining force of said cross bolt means 45 3,114,962 12/1963 Brown. 
to release said separation bolt and to enable said separa- 3,140,886 711964 Cotilla et d. _ _ _ _ _ _ _ _ _  89-l.01 
3,147,663 9/1964 Brown. tion spring to separate said two objects. 
2. Apparatus as recited in claim 1 wherein said means 3,180,389 4/1965 Frank _ _ _  _ _ _ _ _ _  151-69 
for separating said split nut halves comprise a separation 5o 3,299,767 1/1967 Royer. 
nut mounted on each of said split nut halves. 
3. Apparatus as recited in claim 1 wherein there is MARION PARSONS, jR., prima,.,, ~ ~ ~ ~ i ~ ~ ~ .  
UNITED STATES PATENTS 
2,858,726 11/1958 Robinson et al. 
separation bolt, and means for separating said split nut 3,094,928 6/1963 costleyet 89-1.01 
* 


Split nut separation system Patent

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