U.S. patent number 3,645,091 [Application Number 05/064,264] was granted by the patent office on 1972-02-29 for gun-type device for mechanical assembly work utilizing energy of explosion.
Invention is credited to Valery Vasilievich Ivanov, Valentin Ivanovich Rumyantsev.
United States Patent |
3,645,091 |
Ivanov , et al. |
February 29, 1972 |
GUN-TYPE DEVICE FOR MECHANICAL ASSEMBLY WORK UTILIZING ENERGY OF
EXPLOSION
Abstract
A gun-type device for mechanical assembly work utilizing the
energy of explosion. The device comprises a second barrel secured
on the body around the first barrel, the latter being installed
with a provision for axial movement and has a circular projection
functioning as a piston while the first barrel is moving in the
second one, and has channels which intercommunicate the spaces of
both barrels and are located at the side of the circular projection
facing the rod so that at the end of the forward stroke of the
piston with the working tool the compressed gases flow from the
space of the first barrel into that of the second one as a result
of which the first barrel moves and returns the piston with the
tool to the initial position.
Inventors: |
Ivanov; Valery Vasilievich
(Leningrad, SU), Rumyantsev; Valentin Ivanovich
(Leningrad, SU) |
Family
ID: |
22054699 |
Appl.
No.: |
05/064,264 |
Filed: |
August 17, 1970 |
Current U.S.
Class: |
60/638; 60/632;
91/416; 227/10; 60/504; 91/399; 227/9 |
Current CPC
Class: |
B23P
9/025 (20130101); B25C 1/14 (20130101) |
Current International
Class: |
B23P
9/02 (20060101); B23P 9/00 (20060101); B25C
1/14 (20060101); B25C 1/00 (20060101); F01b
029/08 () |
Field of
Search: |
;60/261
;91/399,416,462,235,23 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Burns; Wendell E.
Claims
What we claim is:
1. A gun-type device for mechanical assembly work utilizing the
energy of explosion which comprises: a body with explosion chamber;
a barrel with a space communicating with said explosion chamber,
said barrel being installed in said body with a provision for axial
movement; a piston accommodated in the space of said first barrel;
a rod of said piston carrying a working tool at the end; a second
barrel secured on said body around said first barrel; said first
barrel has a circular projection functioning as a piston while said
first barrel is moving in the space of said second barrel and has
channels intercommunicating the spaces of both barrels and located
at the side of said circular projection facing said rod so that at
the end of the forward stroke of said piston with the rod carrying
the working tool the compressed gases flow from the space of said
first barrel into the space of said second barrel, as a result of
which said first barrel moves and returns said piston with rod and
working tool to the initial position.
Description
The present invention relates to devices for mechanical assembly
work and more specifically it relates to the gun-type devices for
mechanical assembly work, utilizing the energy of explosion.
The invention can be used most effectively for the assembly of
tubular heat exchangers.
Known in the art are the gun-type devices for mechanical assembly
work using the energy of explosion.
These devices comprise a body with an explosion chamber which
communicates with a barrel accommodating a piston with the rod, the
latter carrying the working tool.
The working tool is selected to suit the work in hand; thus,
riveting is done with a striker.
Acted upon by the compressed gases produced by the explosion in the
explosion chamber, the piston with the working tool makes a forward
(working) stroke. For returning the piston to the initial position,
the known devices are provided with a return spring installed
between the barrel and the piston at the side of the rod.
However, experience shows that the mechanical assembly work,
particularly expansion of tubes, punching and calibration of holes
demands that the energy required for the return stroke of the
piston with the working tool and the speed of this stroke should be
approximately equal to the energy spent on the working stroke of
the piston with the tool and to the speed of this stroke. Hence,
the return springs which pull the piston back to the initial
position should be sufficiently powerful. However, the provision of
such springs in the known devices results in spending a
considerable portion of the energy of explosion during the piston
working stroke on compressing the spring.
As a result, the speed of the piston working stroke drops with the
increased resistance of the spring and this drop of speed, in turn,
impairs the accuracy of machining and the surface finish of the
workpieces. Besides, it should be borne in mind that operation of
springs at a pulsating duty, particularly at the initial instant of
explosion and accelerated movement of the piston with the tool,
causes rapid fatigue wear of the springs.
An object of the present invention resides in eliminating the
aforesaid disadvantage.
Another important object of the present invention resides in
providing a gun-type device for mechanical assembly work utilizing
the energy of explosion wherein the piston with the rod carrying
the working tool would make the return stroke only due to the
energy of explosion.
Still another important object of the present invention is to
provide the aforementioned device which would be reliable and easy
to operate.
Still another no less important object of the present invention is
to provide the aforementioned device which would have a broader
field of application than the known devices of the same type.
In accordance with these and other objects, the body of the claimed
device, according to the invention, is provided with a second
barrel fitted around the first barrel, the latter being installed
with a provision for axial movement and having a circular
projection serving as a piston while the first barrel slides in the
second one, and having channels which communicate the spaces of
both barrels and are located at the side of the circular projection
facing the rod so that at the end of the working stroke of the
piston with the tool, the compressed gases flow from the space of
the first barrel into that of the second one as a result of which
the first barrel moves and returns the piston with the tool to the
initial position.
Owing to such an arrangement of the claimed device the piston with
the rod carrying the working tool makes the return stroke only due
to the energy of explosion, without any auxiliary devices which
steps up considerably the operational reliability of the device and
ensures better convenience in operation as compared with the known
devices of the same type.
Besides, the claimed device has a wider field of application than
the known devices of the same type.
Now the invention will be described in detail by way of example
with reference to the accompanying drawing (in which a longitudinal
section of the claimed device is given).
The claimed gun-type device for mechanical assembly work utilizing
the energy of explosion comprises a body 1 with an explosion
chamber 2, a first barrel 3 with space. A communicating with the
explosion chamber 2 and a piston 4 with rod 5 carrying the working
tool 6, said piston being located in said space A.
According to the invention, secured on the body 1 is a second
barrel 7 fitting around the first barrel 3 which is installed in
the body with a provision for axial movement, its outer surface has
a circular projection 8 functioning as a piston while the first
barrel 3 moves in the second barrel 7 and which has channels 9
which intercommunicate the spaces of both barrels. These channels
are located at the side of the circular projection 8 facing the rod
5 so that at the end of the working stroke of the piston 4, space A
of the barrel 3 communicating with the explosion chamber 2 is also
in communication with space B of the barrel 7.
The barrel 7 is secured on the body 1 by means of a screw joint for
easier assembly and disassembly of the device.
At the side of the rod 5, the barrel 7 has a removable centering
bushing 10. Located between the barrel 7 and said bushing is a
circular retainer 11 for holding the rod 5 together with the piston
4 in the initial (extreme right) position.
The barrel 3 is loaded on the body 1 by a compression spring 12 one
end of which bears against the blind end of the barrel, the other
end bearing against the stop 14 which is adjusted by screw 13.
The compression spring 12 is intended to return the barrel 3 to the
initial position. Adjustment of the force of compression of the
spring 12 makes it possible to change the length of the working
stroke of the piston 4 which, in turn, allows the striking force of
the working tool to be changed to suit the work in hand at one and
the same explosive charge, i.e., at the same energy of
explosion.
Now we shall consider an example of using the claimed device for
expanding tubes in the tube plates by the use of mandrels.
In this case the working tool 6 of the device is a mandrel secured
to the rod 5 by any one of the known methods. In the present
example, the rod 5 is made integral with the mandrel.
The rod 5 with piston 4 is held in the initial position by means of
the circular retainer 11. At this moment the piston 4 occupies the
extreme right position in space A of the barrel 3.
Then an explosive charge is placed into the explosion chamber 2 and
the device is aligned with relation to the tube 16 which is to be
expanded in the tube plate 15. For this purpose the bushing 10 is
put against the end of the tube 16 protruding from the tube plate
15.
Then the explosive charge is ignited in the explosion chamber 2 by
means of a trigger mechanism 17 which is well known to those
skilled in the art and is not, therefore, dealt with in the present
description. The compressed gases produced by the explosion flow
from the chamber 2 through channels 18 into space A of the barrel 3
and move the piston 4 with the rod 5 and mandrel to the extreme
left position; it means that the piston has made a forward
(working) stroke in space A of the barrel 3.
The mandrel expands the tube 16 in the hole of the tube plate
15.
At the end of the forward stroke of the piston 4, space A of the
barrel 3 communicating with the explosion chamber 2 is also put in
communication with space B of the barrel 7 through the channels 9.
The compressed gases pass through these channels from space A of
the barrel 3 into space B of the barrel 7 and, acting upon the
circular projection 8 of the barrel 3, move the latter axially,
compressing the spring 12. The piston 4 with the rod 5 and the
mandrel return to the initial (extreme right) position and are held
there by the circular retainer 11 interacting with the rod.
Then the compressed gases are exhausted into the atmosphere through
the channel 19 from space B of the barrel 7, the barrel 3 moving in
space B of the barrel 7 being returned by the spring 12 to the
initial position.
Then the entire operating cycle is repeated.
Thus, in the claimed device, the piston with the rod carrying the
working tool makes the return stroke also under the effect of the
compressed gases produced by the explosion which guarantees a high
reliability of the device and facilitates its operation.
Besides, thanks to its design, the device according to the
invention has a wide field of application since it can be used not
only for riveting and marking but also for piercing of holes,
expansion of tubes with mandrels with a high accuracy and surface
finish, i.e., for such operations which call for high speeds and
power of both the forward and return strokes of the piston with the
rod and the working tool.
* * * * *