A first shaft is connected to a source of rotational power and has a gear fixedly mounted on the shaft. A second gear is fixedly mounted on a gear shaft that is parallel to the first shaft. A third gear, also fixedly mounted on gear shaft, meshes with a fourth gear fixedly mounted on the output shaft. The first input shaft and output shaft are rotatably mounted through a housing that is itself rotatable with respect to a support. Both shafts are coaxial and in end-to-end relationship. A second input shaft is connected to a second source of rotational power. A fifth gear, fixedly mounted on second input shaft, meshes with a sixth gear, which is fixedly mounted on rotatable housing and in coaxial relationship with first input shaft. In operation, the first drive source and gear train provide rotational power in a first direction to drive the output shaft in a given direction of rotation. The second source of rotational power may be operated either to decrease the rate of rotation imparted to the output shaft by the first source of rotational power, or to increase that rate of rotation, depending on which direction the housing is rotated by the second source of rotational power

Webster, L. D.

English

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The invention disc'osed in this document resulted from
resear_h in aeronautical and space activities performed und6r
programs of the National Aeronautics and Space Administration.
The invention is owned by NASA and is, therefore, available
for licensing in accordance with the NASA Patent Licensing
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Address inquiries and all applications for license for
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Mail Code 200-11A, Moffett Field, California, 94035. Approved
NASA forms for application for nonexclusive or exclusive
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N7,1
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(NASA-Case-ARC- 11325- 1) CLUTCHLESS MUL11PLL	 S82-22496
DitIVE SOURCE FOR OUTPUT ShAF2 Latent
Application (NASA) 11 p hC A02/BF A01
	CSCL 13 	 Unclas
G3/37 18414
rSERIAL NO. 354,126
FILE DATE: 3/2/82
NASA CASE NO. ARC-11325'\
Clutchless
Multiple Drive Source for Output Shaft
Invention Abstract
The subject invention relates to a multiple drive source for an output
shaft which may be driven either concurrently or exclusively by separate
sources of rotational power, without requiring the use of a clutch and
without using a planetary gear.
A multiple drivc source (10) for output shaft (12) has a first shaft (14)
connected to a first source (16) of rotational power. First shaft (14)
has a first gear (28) fixedly mounted on the shaft. A second gear (32) is
fixedly mounted on a gear shaft (30), which gear shaft (30) is parallel
to'first shaft (14). A third gear (34), also fixedly mounted on gear shaft
(30), meshes with a fourth gear (36), which fourth gear (36) is fixedly
mounted on the output shaft (12). First input shaft (14) and output shaft
(12) are rotatably mounted through a housing (24), which housing (24) is
itself rotatable with respect to base 	 20. First input shaft (14) and
output shaft (12) are coaxial and in end-to-end relationship. A second
input shaft (46) is connected to a second source (42) of rotational power.
A fifth gear (48) is fixedly mounted on second input shaft (46) and
meshes with a sixth gear (54), which is fixedly mounted on rotatable
housing (24), and in coaxial relationship with first input shaft (14).
In operation, first drive source (16) and gear train (56) provide rotational
power in a first direction (60) to drive output shaft (12) in a given direr-.
tion (62) of rotation. The second source (42) of rotational power may he
operated either to decrease the rate of rotation imparted to output shaft
(12) by first source (16) of rotational power, or increase that rate of
rotation, depending on which direction the housing (24) is rotated by the
second source (42) of rotational power.
Prior art multiple drive sources for an output shaft either require the
use of clutches or utilize a planetary gear. This multiple drive source
for an output shaft can provide a 1:1 gear ratio, since it does not utilize
a planetary gear, and it is also capable of being implemented in a smaller,
lower cost form than conventional multiple drive sources for output shafts.
Inventor:
	
Larry D. Webster
Employer:
	
Department of the Army,
Aeromechanics Laboratory,
AVRADCOM
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SERIAL N0. 354,126
FILE DATE: 3/2/82
1 NASA Case No. ARC-11325-
2
	
3
	 CLUTCHLESS MULTIPLE DRIVE SOURCE FOR OUTPUT SHAFT
4
5 Origin of the Invention
	
6
	 The invention described herein was made by an employee
7 of the United States Government and may be manufactured and
8 used by or for the government for governmental purposes with-
9 out the payment of any royalties thereon or th.=refor.
10
11 Field of the Invention
	
12
	 This invention relates to an improved clutchless mul-
13 tiple drive source for an output shaft. More particularly,
14 it relates to such a multiple drive source that is both low
15 in cost and which may be embodied in physically small form.
16 Most especially, it relates to such a multiple drive source
17 which can be impleme:ited with a 1:1 gear ratio and without
18 any intervening clutch.
19
20 Description of the Prior Art
	
21
	 There is a wide variety of gear drives known in the art
22 for connecting a source of rotational power, such as a gaso-
23 line engine or an electric motor, to an output shaft. Many
^4 of those gear drives are of the type for connecting a plural-
25 ity of separate power sources to a common output shaft.
26 Examples of such gear drives are described in U.S. Patents
27 2,180,599; 2,660,860; 2,971,402; 3,457,806; 3,507,173; and
28 3,748,927.
	
29
	 The multiple drive sources as disclosed in the above
30 prior art either have clutches for disconnection of one of
31 the power sources or incorporate planetary gears to allow
32 the use of more than one power source simultaneously under
33 different operating conditions. Such gear drives tend eitheri
34 to be complex or bulky in their construction, so that they
35 have achieved acceptance primarily in relatively heavy duty
36 situations, such as driving an aircraft propeller from more
37 than one internal combusion engine. Planetary gear drives
-2-
1 are. employed where their physical bulk is not a problem
2 and it is desired to avoid the use of a clutch mechanism
3 in a multiple drive source. However, in addition to their
4 bulk, another disadvantage of planetary gear drives is that
5 a 1:1 gear ratio cannot be achieved with them.
	
6	 Thus, despite the long history of multiple drive
7 sources, a need still remains for further development
8 nf such drive sources to meet situations in which a clutch-
9 'Less drive which is physically small, low in cost and which
10 can provide a 1:1 gear . • a f .^ o is needed.
i	 11
12 Summary of the Invention
	13	 Accordingly, it is an object of this invention to
14 provide a clutchless, non-planetary gear multiple drive
15 source for an output shaft.
	
16	 It is another object of the invention to provide a
17 clutchless, multiple drive source for an output shaft,
18 which drive can prow=de a 1:1 gear ratio.
	
19	 It is a further object of the invention to provide
20 a clutchless, multiple drive source for an output shaft
21 which can be implemented in a physically small, low cost
22 configuration.
	
23	 The attainment of these and related objects may be
24 achieved through use of the novel multiple drive for an
25 output shaft herein disclosed. This drive has a first
26 shaft connected to a first source of rotational power. A
27 gear train is mounted in a rotatably movable housing. The
28 gear train op.,ratively connects the first shaft and the
29 output shaft. The first shaft and the output shaft are
30 coaxial. A second shaft is connected to a second source
31 of rotational power mounted so as to be stationa:.•y, other
32 than with respect to the rotational power, with respect
33 to the first source of rotational power. There is a
34 means for coupling rotational motion from the second shaft
35 to the rotatably movable housing.
36
37
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In operation, the first drive and the gear train may
provide rotational power in a first direction to drive the
output shaft in a given direction of rotation. The second
source of rotational power may be operated either to
decrease the rate of rotation imparted to the output shaft
by the first source of rotational power, or increase that
rate of rotation, depending on which direction the housing
is rotated by the second source of rotational power.
The attainment of the foregoing and related objects,
advantages and features of the invention should be more
readily apparent to those skilled in the art after review
of the following more d(Ifailed description of the invention
taken together with the drawing, in which:
Brief Description of the Drawing
	 I
The sole figure of drawing is a perspective view of
a multiple drive for an output shaft in accordance with the
invention.
Detailed Description of the Invention
Turning now to the drawing, the multiple drive 10
for output shaft 12 has a first shaft 14 connected to a
first source 16 of rotational power, such as an electric
motor. Support 18 is bolted or otherwise fixedly mounted
to base 20. First shaft 14 is rotatably mounted in support
22, also fixedly mounted to base 20. The first shaft 1.4
is also rotatably mounted in housing 24, and support 26 Is
fixedly mounted to housing 24. Housing 24 is itself free
to rotate. A first gear 28 is fixedly mounted on first
shaft 14. A gear shaft 30 has a second gear 32 fixedly
mounted on it, with the second gear 32 in meshing relation-
ship with first gear 28. Gear shaft 30 is rotatably
mounted in horsing 24. The gear shaft 32 has a third gear
34, also fixedly mounted to the shaft 30. Third gear 34
meshes with a fourth gear 36, which is fixedly mounted
on the output shaft 12. The output shaft 12 is rotatably
mounted in housing 24, in support 38 fixedly mounted within)
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the housing 24, and to support 40, which is fixedly
mounted to the base 20.
A second source 42 of rotational power, such as an
electric motor, is also fixedly connected by a support 44
to base 20. The second source of power 42 is operatively
connected to a second shaft 46. The second shaft 46 is
parallel to the first shaft 14, the output shaft 12, and
the gear shaft 30. A fifth gear 48 is fixedly mounted on
the second shaft 46. The second shaft 46 is rotatably
suppo::.ed by supports 50 and 52, which supports are fixedly
mounted to base 20. Fifth gear 48 is in meshing engagement
with sixth gear 54, which is fixedly mounted to the rota-
table housing 24. Sixth gear 54 is concentrically disposed
relative to the first shaft 14, which is free to rotate
with respect to the sixth gear 54. Since the output shaft
12 is axially disposed in end-to-end relationship with the
first shaft 14, the sixth gear 54 is also concentrically
disposed relative to the axis of shaft 12. In a preferred
embodiment, the fifth and sixth gears 48 and 54 have a
1:1 gear ratio, though any gear ratio is possible. The
first through fourth gears 28, 32, 34 and 36 provide a
500:1 gear ratio in the depicted embodiment, although the
gear sizes actually shown in the drawing are much closer
in size than necessary to provide that ratio, for
simplicity in the drawing. It should be recognized that
a gear train of parallel shaft gears of any desired ratio
could be used for gears 28, 32, 34 and 36 comprising
gear train 56.
There are certain relationships which arc useful for
an understanding of the operation of multiple source drive
10. First shaft 14 provides rotational power to the output
shaft 12 through the gear train 56 contained within rota-
table housing 24. Rotations of the first shaft 14, refer-
enced to housing 24 of gear train 56, are capable of rotat-
ing the output shaft as a function of the gear ratio of the
gear ratio of the gear train 56, RGT56 where:
(1)	 RGT56 m	 1
TS1
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wherein TSl equals the number of turns first shaft 14 must
make, relative to housing 24 of gear train 56, to cause
output shaft 12 to turn one complete revolution, also
referenced to housing 24 of gear train 56. First shaft 14
and the output shaft 12 are not physically connected.
Torque, and therefore movement, is transferred from first
shaft 14 to output shaft 12 through gears 32 and 34, whose
center of rotation is not coaxial with respect to first
shaft 14. RGT56 may take on any physically attainable
value and gear train 56 may then act as either a coaxial
speed reducer or a coaxial speed increaser.
Gear 48 and gear 54 comprise a second gear train 58
in its simplest form. Gear 48 is physically attached to
second shaft 46 and rotates directly with it. Gear 54 is
physically connected to housing 24 of gear train 56 and
has an axis of rotation that is coincident with the axis
of rotation of output shaft 12. Gear 48 drives gear 54.
Rotations of secor..d shaft 46 are capable of rotating
housing 24 as a function of the gear ratio 
RGT58, where:
(2) RGT58 -	 1TS2,
wherein TS2 equals the number of turns second shaft 46 must]
make, referenced to base
	
20, to cause the gear train 56
housing 24 to rotate one complete revolution, also with
respect to base
	 20. Unlike the gear ratio in a
planetary gear train, gear ratio RGT58 may take on any
physically attainable value, including 1:1.
The angular velocity of output shaft 12, Bout,
referenced to base
	 20, in response to the input angular
velocities of the first and second shafts 14 and 46, may be
expressed:
(3)
;out M RGT56 8 1 - RGT58 8 2 (1-RGT56)
where 8 1 and ; 2 are the angular velocities, referenced to
base	 20 of first draft 14 and second shaft 46,
-6-
1 respectively. The positive sense for each shaft 14, 12
2 and 46 is shown in the drawing by arrows 60, 62 and 64,
3 respectively. Relationship ( 3) shows that both input
4 shafts 14 anC 46 may rotate output shaft 12 with respect
5 to base	 20 concurrently, or exclusively, and with no
6 intervening clutch. The exact relationship of input shaft
7 14 and/or 46 is output shaft 12 velocity is directly a
8 function of the two near ratios 
RGT56 and RGT58-
9
	
Sim.11arly, the change in angular position of output
10 shaft 12,AGout'
 with respect to support 2D, in response to
3.i chang	 i • :-agular positions of the input shafts 14 and 46,
12 A3 1
 dn; AA 2 respectively, may be expressed:
13^
14
	 (4)	
Aeout 00 RGT56Ae1 - RGT58Ae 2 (1-RGT56)
15
16 Relationship (4) shows that both input shafts 14 and 46
17 may alter the angular position of output shaft 12 conrur-
18 rently or exclusively, and without the use of an intervening
19 clutch.
20
	
In an alternative form of the invention, the functions
21 of input shaft 46 and output shaft 12 could be exchanged.
22 A second source of rotational power connected to shaft 12
23 would then drive shaft 46 through gear train 58. Shaft 12
24 in this embodiment then becomes a part of gear train 56
25 housing 24. For this embodiment, relationships (3) and
26
	 (4) above would be slightly modified.
27
	
It should now be apparent to those skilled in the
28 art that a novel multiple drive source output capable of
29 achieving the stated objects of the invention has been
30 provided. A multiple drive source for an output shaft
33.	 that is clutchless and which does not utilize a planetary
32 gear is provided, so that a 1:1 gear ratio is attainable.
33 Further, because a planetary gear is not employed, this
34
	
multiple drive source for an output shaft can be imple-
35
	
mented in a physically small, low cost configuration.
36
	
It should further be apparent to those skilled in the
37
	
art that various changes in form and details of the
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invention as shown and described may be made. it is
intended that such changes be included within the spirit
and scope of the claims appended hereto.
- 9-
PECOM PAGE BLANK NOT FWED
l-
s
1 NASA Case No. ARC-11325
2i
	
3
	
ABSTRACT OF THE DISCLOSURE
4i
	
5
	
A multiple drive source (10) for output shaft (12) has
6 a first shaft (14) connected to a first source (16) of
7' rotational power. First shaft (14) has a first gear (28)
8 fixedly mounted on the shaft. A second gear (32) is
9 fixedly mounted on a gear shaft (30), which gear shaft (30)
10 is parallel to first shaft (14). A third gear (34), also
11' fixedly mounted on gear shaft (30), meshes with a fourth
121 gear (36), which fourth gear (36) is fixedly mounted on
13 the output shaft (12). First input shaft (14) and output
14 shaft (12) are rotatably mounted through a housing (24),
151 which housing (24) is itself rotatable with respect to
16 support 20. First input shaft (14) and output shaft (12)
17 are coaxial and in end-to-end relationship. A second
18 input shaft (46) is connected to a second source (42) of
19 rotational power. A fifth gear (48) is fixedly mounted
20 on second input shaft (46) and meshes with a sixth gear
	
21
	 (54), which is fixedly mounted on rotatable housing 24,
22 and in coaxial relationship with first input shaft (14).
23 In operation, first drive source (16) and gear train (56)
24 provide rotational power in a first direction (60) to
25 drive output shaft (12) in a given direction (62) of
26 rotation. The second source (42) of rotational power may
27 be operated either to decrease the rate of rotation
	
28
	
imparted to output shaft (12) by first source (16) of
29 rotational power, or increase that rate of rotation,
30 depending on which direction the housing (24) is rotated
31 by the second source (42) of rotational power.
32
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Clutchless multiple drive source for output shaft

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