Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
326830
23J7
This invention relates to drive assemblies,
and more particularly to a drive assembly that is
particularly suitable for use as a rotary internal
combustion engine.
A multitude of designs have been pr~posed for
rotary internal combustion engines over the years and
yet, despite the multiplicity of such rotary designs,
and despite the obvious advantages of unidirectional
movement inherent in the rotary design, the
reciprocating variety of engine continues to account for
the vast majority of internal combustion engines sold.
This presumably is because the various rotary designs
proposed have either been too complex to manufacture on
~,
.
. !
. ,
'"
', ~
1 326830
SrF-Olg - 2 - 23J7
a large scale, have been inefficient in operation, have
required an inordinate amount of maintenance, or have
had a relativel~ short ~roduct life.
This invention relates to a rotary internal
combustion engine of the type in which two rotating
pistons or vanes are connected to concentric shafts or
hubs with the leading and following pistons rotating in
a manner that allows the pistons to alternately approach
and move away ~rom each other to permit the inta~e of a
combustible fuel mixture, its compression, ignition,
expansion and exhaust. Prior art rotary internal
combustion engines of this type have suffered from an
inability to convert the somewhat promiscuous and
seemingly random movement of the two pistons into a
predictable, usable movement of an output shaft. Prior
art attempts to provide a predictable or usable movement
of the output shaft have involved the attempted use of a
predetermined program to control the compression and
expansion strokes wherein a fixed program of motion
between the pistons is established by the use of cams,
lobes, planetary gears, cranks, grooves, slots, rollers
or other similar lin];ages. However, these prior art
attempts to provide a predictable, usable movement of
the output shaft by providing a predetermined fixed
program of motion between the pistons have been
' ' ' ' ''~ ' ~, , . ,, ~1, ,
1 326830
STF-018 - 3 - 23J7
unsuccessful since they have generated uncompensated
s~resses ~hich have tended to literally tear the engine
apart. They have also resulted in engine designs that
are unduly complex, undul~ expensive to manufacture, and
which require an inordinate amount of maintenance.
This invention is directed to the provision of
an improved rotary internal combustion engine of the
rotary piston type.
More specifically, this invention is directed
to the provision of a rotary internal combustion engine
having improved provision for engine starting and
improved provision for reliable engine operation under
idle conditions.
The invention engine includes a housing; a
first piston or vane mounted for rotation in the housing
on a fixed axis; a second piston or vane mounted for
rotation in the housing on the fixed axis independently
of the first vane; control means precluding rotation of
either vane in one direction about the axis while
allowing free rotation in the other direction about the
,; axis so that the vanes may rotate freely in the other
direction and may simultaneously undergo relative
rotation; converter means, including an output shaft,
,,
,,
. ~ .
, . .
,: , .
: . ~
, : , , . . ::
~ 3~6830
STF-O1~ - 4 - 23J7
drivingl~ connected to the vanes and operative to
convert the rotation of the vanes in such other
direction as ~ell as t)le relative rotation of the vanes
into a unidirectional, steady speed rotation of the
output sha~t of the converter means; and means for
delivering a charge to the housing under a boost
pressure.
The rotary vanes are mounted on concentric
shafts and the concentric shafts in turn are drivin~ly
connected to separate elements of the converter means.
Tne separate elements in the converter means operate to
drive the output shaft of the converter means at a
uniform, constant speed. The concentric shafts of the
two rotary vanes are precluded from rotation in the
opposite direction by ratchet means which respectively
coact with each of the concentric shafts.
In one embodiment of the invention, the
converter means comprises a differential gear assembly
in which the concentric shafts, which are rotating in
the same direction but at different speeds, are coupled
to different pinions in the differential gear assembly
and the pinions coact in ~nown differential gear manner
to rotate the output shaft of the differential gear
assembly in a unidirectional, constant speed manner.
. .
.
. , .
- - . . -
: . .
1 326830
STF-018 - 5 - 23J7
~ccording to another embodiment of the
invention, the converter means ma~ comprise a pneumatic
coupling ~hich is comprised of vanes which move in the
same pattern as the vanes of the engine.
According to a further embodiment, the
, converter means may comprise a h~draulic coupling, and
¦ according to a still further embodiment, the converter
means may comprise a hydraulic differential coupling.
In each of the embodiments, and according to
an important feature of the invention, a charge is
continuously delivered to the housing under a boost
pressure by the use of, for example, a supercharger
driven by the output shaft of the engine. The charge
under boost pressure facilitates starting of the engine
by providing relative rotation between the vanes;
optimizes engine power under steady state operation by
increasing the charge delivered to the engine; and
precludes stalling of the engine under idling conditions
by ensuring that a charge is delivered under pressure
between the vanes.
IN THE DRAWINGS:
.,'. ~.
;~ FIGURE 1 is a schematic, longitudinal cross-
~ sectional view of the invention engine;
~,
t.-~. . : : . : . : ' :
1 326830
STF-01~ - 6 - 23J7
FIGURE 2 is a transverse cross-sectional view
ta~:en on lines 2-2 of FIGU~E 1;
FlGURE 3 is perspective view of the piston
vane assembly used in the engine of FIGURE 1;
FIGURE 4 is a cross-se^tional view of the
converter means shown in the engine of FIGURE 1;
FIGURE 5 is a transverse cross-sectional view
taken on lines 5-5 of FIGURE 1;
FIGVRE 6 is view of an alternate form of
converter means for use in the engine of FIGURE 1s
FIGURE 7 is a cross-sectional view taken on
line 7-7 of FIGURE 6;
FIGURE 8 is a view of another alternate form
of converter means for use in the engine of FIGURE 1;
FIGURE 9 is a cross-sectional view taken on
line 9-9 of FIGURE 8;
FIGURE 10 is a view of a still further
alternate converter means for use in the engine of
FIGURE 1; and
FIGURE 11 is a cross-sectional view taken on
line 11-11 of FIGURE 10.
i
The rotary internal combustion engine seen in
schematically and in longitudinal cross section in
. .
.,.
::
1 326830
STF-ol~ - 7 - 23J7
Figure 1, ~roadly considered, includes a housing 10; a
rotar~ piston assembl~7 12; a ratchet assembly 14, and a
converter mechanism 16.
Housing lO is cylindrical and defines a
c~lindrical combustion chamber l~. A spar};plug or glow
plug 20 is provided at a top dead center location in the
housing and communicates with combustion chamber 18, and
inta~e and e~:haust ports 22 and 24 are provided adjacent
the lower end of the housiny generally opposite plug 20.
For example, the i.nta~e and eYhaust ports may be located
on opposite sides of, and approximately twenty degrees
from, the bottom dead center or six o`clock position on
the housing. Pins lOa are provided for cooling housing
10 .
Rotary piston assembly 12 is positioned within
housing 10 and includes a first shaft or hub 26
including a~ially spaced separate portions 26a and 26b;
a pair of bearings 28 and 30 positioned in opposite side
walls of housing 10 and respectively journalling shaft
portions 26a and 26b; a shaft o_ hub 32 concentric with
shaft 26 and journalled within shaft 26; a first rotary
vane or piston 34 secured to shaft portions 26a and 26b,
and a second vane or piston 36 secured to shaft 32.
Vane 34 includes first and second portions 34a
and 34b. Portion 34a is secured to shaft portion 26a
STF-018 ~ 8 - 1 326830 23J7
along inner vane edge 34c and is secured to shaft
portion 26b at 34d with an intermediate inner vane edye
portion 34e closely but slideably interfacing with
sha t 32. Vane portion 34b is secured to shaft portion
26a along inner vane edge 34f and is secured to shaft
portion 26b at 34g with an intermediate vane edge
portion 34h closely but slideably interfacing with shaft
32.
Vane 3G includes first and second portions 36a
and 36b. Vane portion 36a is secured to shaft 32 along
inner vane edye 36c and closely but slideably interfaces
with shaft portion 26a at 36d and with shaft portion 26b
at 36e. Vane portion 36b is similarly mounted and
disposed with respect to shaft 32 and shaft portions 26a
and 36b. Vanes or pistons 34 and 36 are configured to
fit as tightly as possible within the combustion chamber
without actually touching the walls of the chamber as
they rotate relative to the chamber. If desired, an
internal lubricant or oil may be used to protect the
edges of the pistons and the adjacent walls of the
chamber although, with proper control of the fit between
the pistons and the walls of the combustion chamber, an
internal lubricant may not be necessary. As seen, the
pistons have a generally wedge shaped configuration.
~lthough other piston shapes may be used, the disclosed
.
1 326~30
STF-018 - 9 - 23J7
wedge shape is desirable because, as the pistons
approach each other during their relative rotation
within the combustion chamber, their faces move into 2
parallel relationship to minimize the danger of any
protrusions on the faces of either piston coming into
contact with the adjacent piston.
Ratchet assembly 14, as best seem in FIGURES 1
and 5, includes a pair of ratchet mechanisms 38 and 40
respectively associated with each of the concentric
shafts 26 and 32. Ratchet mechanisms 38 and 40 are
disposed side-by-side in axially spaced relation in a
circular housing 42. Housing 42 includes an end wall
42a upstanding from a suitable support surface 43 and
supporting bearing 30 and thereby one end of housing 10.
The other end of housing 10 is supported by a support
plate 44 upstanding from surface 43 and supporting
bearing 28.
Each ratchet mechanism includes a circular
ratchet body 45 secured to the respective shaft and a
plurality of balls 46 respectively ensconced in a
plurality of circumferentially spaced pockets 48
provided on the periphery of ratchet body 45. Ratchet
body 45 and balls 46 coact in };nown manner with housing
42 to preclude counterclockwise rotation of the
.
,
'
,:
.
1 326830
STF-Ol& ~ 23J7
respective shaft as viewed in Figure 5 while allowing
free clock~ise rotation of the respective shaft.
converter mechanism lG, as b~st seen in ~igure
4, includes a housing 50, an output shaft 52 fixedly and
centrally secured to housing 50, and a plurality of
pinion bevel gears 54, 56, 58 and 60 positioned within
housing 50. riniOn gear 54 is drivingly secured to shaft
32; pinion gear 56 is drivingly secured to shaft portion
26a; and pinion gears 58 and 60 are meshingly engaged
with gears 54 and 56 and secured in axially spaced
relation on a pinion shaft 62 which in turn is
j ournalled at its upper and lower ends in j ournal
portions 50a and 50b of housing 50.
The engine further includes a supercharger 64
including a blower 66 drivingly connected to output
shaft 52 of converter mechanism 16 by reduction gears
6~, 70, 72 and 74. A suitable conduit 76 interconnects
the output of supercharger 64 with the intake port Z2 of
housing 10.
OPERP.TION
To start the engine, an electric motor 77
engages gear 52 to rotate output shaft 52 to impart
initial rotation to pistons 34, 36. In order to impart
differential rotation as well as absolute rotation to
the pistons, supercharger 64 operates to supply a fuel
.
i~
;
~ 326830
STF-01& ~ 23J7
mi~ture charge to the intake a2 under boost pressure.
~his charge begins the compression and expansion strokes
of the engine. Instead of a supercharger, a
turbocharaer or other suitable means for supplying a
charge un~er boost pressur~ may be employed. For the
sake of simplicity, a carburetor or other fuel mixing
device is not shown in the drawings. The movement of
the pistons 34, 36 through the various phases of the
engine operation is best seen in Figure 2. With the
pistons 34 and 36 in the position seen in Figure 2, the
sparkplug 20 is energized to ignite the fuel mixture
confined by piston portions 34a and 36a. As the fuel
burns and expands, it acts against piston portion 36a to
force piston 36 to rotate in a clockwise direction. The
piston 34 is prevented from counterclockwise rotation by
ratchet mechanism 38. Alternatively, a unidirectional
clutch, hydraulic system with check valves, or other
control means miyht be used. As piston portion 36a
approache~ piston portion 34b, burned combustion
products from the previous ignition are expelled through
exhaust port 24. At the same time, a new fuel air
mixture is drawn in through intake port 22 as piston
portion 36b separates from piston portion 34b, and the
charge confined in the area between piston 36b and
piston portion 34a is compressed. As piston portion 36b
:
: . . : , .
~ - 12 ~ 1 32 6 8 3 0
moves close to piston portion 34a, the build-up of pressure
in the space between the two piston portions forces piston
portion 34a to move past sparkplug 20 and a new charge is
ready for firing to complete the cycle.
Just before the sparkplug ignites the new charge,
both pistons 34 and 36 are moving in a clockwise direction.
After the firing, the relative rates at which piston 34
decelerates and piston 36 accelerates can be determined by
the following analysis:
Let:
F equal the clockwise force on a pair of pistons
A equal the area on one side of a piston
T equal time
S equal speed
P36a34a equal pressure between vane portions 36a and 34a
P34a36b equal pressure between vane portions 34a and 36b
P36b~34b equal pressure between vane portions 36b and 34b
P34b36~ equal pressure between vane portions 34b and 36a
Then:
1. F34 = AP36a-34a + AP34a-36b AP36b-34b + AP34b-36a
2. 1~36 = AP36--3-- - AP3~-~36~ AP3~--36b + AP36b-3 b
~1 .
`X~ :
: ~ . . . - . . : . .
.
.
: . ~ -.' : `
- 13 - ~ 32 68 3 0
3. F34 = -F36
Assuming the mass of the concentric shafts are
the same and the two pistons are equal in size, from
F = mass x acceleration = mass x S
~ 5 4. ~S34 36 or ~Sz6 32
., ,
.( From the geometry of a differential gear coupling
.~ . 5. 1/2Sz6 + l/2S32 = Ss2
,;
,, .
where S26, S32 and S52 are the respective speeds of concentric
~ shaft 26, concentric shaft 32, and output shaft 52.
,,~ 10 After a lapse of time equal to ~ T:
,...
!~ 6. 1/2 (S26 + ~S76) + 1/2 (S32 + ^S3z) S52 + ~Ss2
..'~
,.. .
~ or
.j~
, . . .
7. 1/2AS26 + 1/2~S32 ~SS2
''~.
i,~'::
.
!.
! '
~ . .
., .
',''''
......
~,.......................................................................... .
'`'''~ X''
;~.,
:
.~ .
.` ` ~ ' ~ ' .
'~ . ~ ` . ' ' ., . ' :
~', ' ' ' ' '~ ' ' . . '
,
'
- 14 - ~ 3268 30
by substituting equation 4. in equation 7.
8. ~Ss2 = 0
Thus, for a given engine throttle setting, the
output speed of the drive shaft 52 is constant as the
pistons 34 and 36 alternately accelerate and decelerate
during the engine cycle. When a particular piston is
held stationary by its ratchet mechanism, the speed of
the drive shaft 52 equals 1/2 of the speed of the other
or moving piston.
Supercharger 64, in addition to imparting
relative rotation to the vanes in order to facilitate
starting of the engine, also functions during steady
state operation of the engine to increase the charge
delivered to the engine and thereby optimize engine
power. Supercharger 64 also functions during idling
conditions to preclude stalling of the engine. Unlike
reciprocating engines, as well as rotary engines with
programmed movements, the rotary engine of the invention
permits the vanes to rotate freely and therefor has no
fixed displacement. When the engine is throttled back to
an idle mode, the vanes, in the absence of supercharger
64, would continue to rotate but would not
~i
- - `
STF-018 1 326830 23J7
undergo relative rotation so that no fuel charge would
be suc}:ed lnto the engine and the engine would soon
stall. Supercharger 64 functions under idling
conditions to deliver a charge under boost pressure
between the vanes to ~:eep the engine from stalling.
~lthough a differential gear assembly is
eminently satisfactory for use with the invention rotary
internal combustion engine, other converter mechanisms
ma~ be used. For example, as seen in Figures 6 and 7, a
pneumatic coupling -~ m~y be used ~s the converter
mechanism.
ji Coupling 78 includes a housing 80 and vanes ~2
', and 84. Housing 80 is generally circular and defines a
3 central chamber 86 within which vanes 82 and 84 are
disposed. Output shaft 52 is defined centrally and
integrally with one side wall 80a of the housing and
four internal vanes 88 are provided integral with the
housing and projecting radially inwardly from the outer
shell of the housing. Shafts 32 and 26a are suitably
,l 20 journalled in side walls 80a and 80b of the housing.
Vane Z2 includes vane portions 90 and 92 secured to
shaft 26a in a manner similar to the securement of
piston 34 to shaft 26a. Vane 84 includes vane portions
94 and 96 secured to shaft 32 in a manner similar to the ,
~i 25 securement of piston 36 to shaft 32. A compressible gas
.;..
,
i .
~ 16 - t 326830
is contained within the housing. Housing vanes 88 will
move so as to remain equidistant between vanes 82 and 84.
This behaviour assumes that the vanes fit airtight and
that the inertia in the output shaft can be ignored. The
above relationship can be expressed mathematically as
follows:
Let e equal the location of a vane.
Then:
. 1. e94 - e88= e88 ~ e9o
After a time lapse of ~ T, vane 94 will be at e94 + ~e94;
vane 90 will be at e90 + ~e90; and housing vane 88 will
be at e~ + ~e~ so that:
,~ 2. e94 + ~e94 - e~ - ~e~ = e~ + ~e~
; By combining equations 1 and 2:
~
" .
3. ~e94 - ~e~ = ~e~ - ~e90
p~
~ or
''"'
~, ~.
~ r~
. ~
. ~: . . . :; ' , ~ , , .
- 17 ~ l 32 6 8 30
4. ~,e94 + ~e90 = 2~e88
Dividing equation 4 by 2 ~ T, the following expression is
obtained:
5. l/2S94 + 1/2S90 = S~
This equation will be recognized as the same as the
equation describing the motion of the differential gear
coupling 16. Thus, for the purposes of this invention,
the differential gear coupling 16 and the pneumatic
coupling 78 perform identically and may be used
interchangeably.
Other types of converter mechanisms may also be
employed. Thus, referring to Figures 8 and 9, a
hydraulic coupling 9O may also be employed as the
converter mechanism. Coupling 9O includes a housing 92
and a pair of vanes 94 and 96. Housing 9O has a multi-
lobe configuration in cross section and includes a series
of circumferentially spaced internal vanes 98 extending
radially inwardly from the outer shell of the housing.
Vanes 94 and 96 are se~ured to shafts 26a and 32
in the same manner described previously with
~ Xl
. ' . ' ~, ' '
:., : . ,
.
.. , . ;:, :
.: :.,. ~ ,
1 326830
STF-018 - 18 - 23J7
,
reference to the securem~nt of vanes 34 and 36 to shafts
~6a and 32.
y The lobed configuration of the casing has the
effect of reducing fluid friction while still preventing
.~ 05 the moving vanes 94 and 96 from colliding with the
housing vanes 98.
; A further form of converter mechanism is seen
in rigures 10 ancl ll. The converter mechanism of
, Figures lo and 11 comprises a hydraulic differential
coupling 99. Coupling 99 includes a housing 100; a
~, first gear set 102; and a second gear set 104.
, Housing 100 is generally cylindrical and
~ defines an inner chamber 106 within which gear sets 102
;, and 104 are disposed.
Gear set 102 is associated with shaft 32 and
includes a sun gear 108 keyed to shaft 32; a pair of
planetary gears 110 and 112 meshingly engaging with
~ diametrically opposed portions of sun gear 108 and
.`~ journalled in chamber 106 by shafts 114 and 116; and a
further pair of planetary gears 118,12C meshingly
engaging respectively with planetary gears 110 and 112
and journalled in chamber 106 by shafts 122 and 124.
y~ Similarly, gear set 104 includes a sun gear~~ 126 keyed to shaft 26a; a pair of planetary gears 128
i~ 25 and 130 meshing with diametrically opposed portions of
5~,~
.`
,~ .
','~ ' ~ . ,
~ 326830
STF-018 - 19 - 23J7
sun gear 126 and journalled in chamber 106 on shafts 114
and 116; and a further palr of planetary gears (not
shown) meshingl~ engaging respectivel~ with planetary
~ears 12& and 130 and carried on shafts 122 and 124,
respectivel~7. The four planetary gears that are
associated with each sun gear rotate tangentially to the
inner wall of the housing 100 and they therefore act as
a gear pump. Because these gears oppose each other,
- they are ~ept from rotating about their axes unless
fluid is withdrawn. Under these conditions, where fluid
is neither added or r~moved, the entire housing will
rotate with the sun gear.
The principle on which the coupling of Figures
10 and 11 operates is that the combined fluid flow from
the two gear trains or pumps must be balanced by the
fluid Plow due to the rotation of the housing 100 which
is connected to the output shaft 52. This relationship
leads to the following expressions:
' Let:
;' 20 Q equal flow rate
,~ ~
S egual speed of the shaft
~ C equal capacity oP gear pump
`` Then
; 1. Q102 + Q104 = QloO
And because Q = SC
.
';
.~:
.
1 326830
STF-018 - 20 - 23J7
2- S102 C102 + S104C104 = S10OCloo
Since Cl07 = C104 = 1/2 C10O
. 1/2 5102 ~ 1/2 S10~ = Sloo
This equation will be recognized as the same
equation as that which describes the motion of the
differential gear coupling 16. Thus, for the purposes
of this invention, hydraulic differential coupling 99 is
equivalent to and may be used interchangeably with the
differential coupling 16.
- 10 In addition to the three forms of converter
mechanism disclosed, other forms may be used. For
~ example, a spring or magnetically loaded coupling might
5,~: be used as the converter mechanism.
, With particular reference to Figure 2, the
-~ 15 location of the intake and exhaust ports can be
1 determined by making certain assumptions. For example,
'~, a compression ratio of 8 to 1 can be specified. This
ratio can be realized by allowing the closest proximity
of the pistons to be 20' and the maximum spacing between
~-,; 20 the pistons to be 160'. Further, by assuming that the
build-up of the pressure of the products of combustion
is instantaneous and that the pistons have negligible
momentum, the exhaust port should be located 20' off of
~; the center line. Similar reasoning may be applied to
dictate the location of the intake port.
5i ~ ~
,~ . . -
`':;'
.'i: ~,
'~
.'. , ': ' ,.. ~ ~ ' ' ,.
1 326830
STF-018 - 21 - 23J7
~ The engine design need not be limited to one
s inta~e or one exhaust port. In fact, the invention
engine ideally lends itself to the use of a stratified
charge, thus reducing air pollution without sacrificing
performance. For example, one intake port could supply
an enriched fuel mixture while a second intake port
could introduce a lean mi~:ture.
Figure 2 also helps to illustrate a key
~ feature of the invention whereby the pistons are free to
; 10 move independently of each other. Because the pistons
f~ are free moving, they are able- to automatically
compensate or adjust to changes in operating conditions.
.,;,........................................................................ . For example, the point at which the abutment piston 34a
comes to rest will depend upon such operating variables
as the speed of the engine, its load, the amblent
temperature, and the fuel composition. Thus, pre-
~ ignition or knocking, as experienced in reciprocating
t''~'~ engines using low octane gasoline, should have a minimum
~,; ,
effect on the invention engine. Also, since the pistons
are free moving, a major source of vibration, wear and
~ inefficiency is eliminatéd. This feature also allows
t;` the invention engine to operate at much higher speeds as
compared to other rotary engines or other engines of the
~ ~ reciprocating variety.
t"'`' 25
~, . . .
l~i
~. ,
t.`. ~,
~,
~i''
1 32~83û
STF-01& - 22 - 23J7
Purther modifications of the basic design of
the invention engine are possible. For example, fuel
injection maS~ be used in place of a carburetor; and
rather than employing a sparkplug to ignite the fuel
mi~:ture, a diesel configuration may be used. Also,
more than one combustion chamber ma; be used to provide
additional power.
The advantages of the invention engine are
numerous. Perhaps the m~st dra~atic advantage as
compared to ccnventional internal combustion engineS is
the e~tremely high power output per engine weight.
Another striking feature is the engine s simplicity,
which permits substantial savings in manufacture and
maintenance. Because all moving parts are symmetrical,
vibration is ~ept to a minimum, thus reducing noise,
wear and inefficiencies. Fuel consumption also is
thereby reduced. The engine s relatively high torque
offers potential advantages in simplifying
transmissions. Additional benefits also flow from the
engine s small size and low profile which present many
design advantages, particularly where streamlining is
critical. The provision of means to deliver a charge
under boost pressure is also extremely beneficial since
it facilitates starting of the engine by providing
relative rotation between the vanes; optimizes engine
. ,;
1 326830
STF-018 - 23 - 23J7
power under steady state operation by increasing the
charge delivered to the engine: and precludes stalling
of the en~ine under idlin~ conditions by ensuring that a
charge is delivered under pressure between the vanes.
The invention engine has many practical applications.
For e~ample, the invention engine could serve as a
replacement ~or the standard reciprocating automobile
engine; the invention engine could find applications in
aviation where high power to weight is critical and good
fuel economy is required; and the invention engine could
be used in lawn mowers and motorcycles where its small
size, light weight and simplicity offer important
i advantages. Numerous military applications can also be
imagined.
Whereas preferred embodiments of the invention
, have been illustrated and described in detail, it will
be apparent that various changes may be made in the
disclosed embodiments without departing from the scope
' or spirit of the invention.
..
: , , :. . . :
-,
.
