Note: Descriptions are shown in the official language in which they were submitted.
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1 AUTOMATIC TRANSMISSION SYSTEMS
2 FOR HUMANLY POWERED VEHICLES
3 Technical Field of Invention
4 The technical f field of the invention relates to bicycles and
other humanly powered vehicles and, more specifically, to
6 automatic and hybrid transmission systems for humanly powered
7 vehicles, herein generically referred to as "bicycles".
g Background
9 Forty years ago the automatic transmission for automobiles
was for many people what the electric automobile engine starter
11 had been for an earlier generation. Yet, even though bicycles
12 and the like have been around for as long as the automobile,
13 velocipedists all over the world still do not have automatic
14 transmissions that would actually benefit them on their humanly
powered vehicles.
16 Various proposals for automatic bicycle transmissions have
17 not been widely successful. One recent proposal adds three
1g weights, 120 degrees apart. to the rear wheel. These weights add
19 increased air resistance and more than a kilogram of mass to the
bicycle. Also, these weights respond to rear Wheel speed by
21 centrifugal or centripetal action, shifting a derailleur
22 transmission automatically. In practice, shifting a transmission
23 or derailleurs in response to speed has its disadvantages.
24 Consider for instance approaching an upgrade with a bicycle. In
such a case, the cyclist would pedal harder; his or her reaction
26 being to maintain the speed. This, of course, would delay the
27 necessary shifting of the transmission until the hard pedaling
28 cyclist can no longer maintain the speed. By thus losing speed,
29 the cyclist in effect has to work harder in taking the hill, eves
after the transmission has shifted. Conversely. going downhill
31 and onto a level surface may be hard on the brakes, since that
32 transmission will not shift back until the speed has gone down.
33 Velocipedists thus continue to shift their bicycles manually
34 in response to the load on their legs and feet. This has led to
a continual increase in the number of gears or transmission shift
36 positions with which bicycle transmissions are manufactured,
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1 especially for mountainous driving. A high number of
2 transmission shift positions, in turn, is requiring increasing
3 sophistication of bicycle riders as to how and when to shift, and
4 has been discouraging many people from acquiring one of the more
advanced racing bicycles or "mountain bikes".
6 The problem may be gauged from a commercial eight-speed
7 version is which the speed change or change in drive ratio is 22%
g from the first to the second gear, 15 % from the second to the
9 third gear. 18% from the third to the fourth gear, 21% from the
fourth to the f i f th gear, 2 0 % from the f i f th to the s ixth gear,
1l 17% from the sixth to the seventh gear, and 22% from the seventh
12 to the eighth gear. That the problem has assumed grotesque
13 proportions may be seen from the example of a modern eighteen-
14 speed derailleur-type bicycle having front sprocket control cam
followers and rear sprocket control cam followers providing
16 together the following plethora of drive ratio changes : 22 % from
17 the first to the seconds 11% from the second to the third; 3%
18 from the third to the f ourth; 18 % f rom the f our th to the f i f th;
i9 nothing from the fifth to the sixth, due to the combined action
of the front sprocket and rear sprocket shiftss 4 % each between
21 the sixth and the seventh, the tenth and the eleventh, and the
22 fifteenth and the sixteenth; 9% between the seventh and the
23 eight; 2% between the eight and the ninth; 5% between the ninth
24 and the tenth; 7% between the eleventh and the twelfth, the
twelfth and the thirteenth, the fourteenth and the fifteenth, and
26 the seventeenth and the eighteenth; with only 6% between the
27 thirteenth and the fourteenth; and 13 % between the sixteenth and
28 the seventeenth.
2g This averages out as a ratio change of 0.07166 per shift of
that 18-speed transmission, with actual values being very
31 unequally distributed among the eighteen shift positions. In
32 consequence, more sophistication, concentration and judgment are
33 required for operating the transmission, that what is needed to
34 conduct the;bicycle itself.
Rnown hub type of bicycle transmissions work With one or two
36 planetary gear systems, but are not automatic.
37 Further problems arise from the fact that recurring torque
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1 variations are inherent in many humanly powered drives, such as
2 in bicycles where twice-around drops in torque occur from the
3 fact that the angularly moved pedals in turn have to go through
4 tops and bottoms of their circular motions. This. in turn, has
beset efforts to develop an automatic bicycle transmission with
6 problems of erratic shifting due mainly 'to the above mentioned
7 cyclically recurring power torque variations.
g In consequence, a newer approach thus uses a microprocessor
9 for shifting gears which, however, harks back to the power
assisted manual type of transmission of the old Hudson
1l automobile, circa 1938. A new approach obviously is needed, eves
12 in the case of electromechanical solutions.
13 The prior-art inability to evolve a widely acceptable
14 automatic bicycle transmission is regrettable also from
environmental and socio-economic points of view, since bicycles
16 cost much less and take much less space than automobiles, put
17 less of a load on the road, do not pollute the atmosphere like
18 automobiles, are much less expensive to operate, and subject the
19 rider to continual salubrious exercise unavailable in any
automobile.
21 Sua~marv of the Invention
22 The primary object of the invention is to provide improved
23 automatic bicycle transmission systems.
24 The invention resides in a method of shifting a shiftable
bicycle transmission, comprising, in combination, automatically
26 sensing output power torque of the transmission, automatically
27 converting sensed output power torque to transmission shifting
28 motion, and automatically shifting the shif table transmission
29 with that transmission shifting motion.
The invention resides also in a shiftable bicycle driving
31 power transmission having a transmission shifting element,
32 comprising, ,in combination, a bicycle output power torque sensor,
33 and an output power torque-to-transmission shifting motion
34 converter having an output power torque input coupled to that
output power torque sensor and having a transmission shifting
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1 motion output, such transmission shifting element being coupled
2 to the transmission shifting motion output of the converter.
3 Brief Description of the Drawings
4 The subject invention and its various aspects and objects
will become more readily apparent from the following detailed
6 description of preferred embodiments thereof, illustrated by way
7 of example in the accompanying drawings which also constitute a
8 written description of the invention, wherein like ref erence
9 numerals designate like or equivalent parts, and in which:
Fig. 1 is a side view of a relevant portion of a.bicycle
11 representative of bicycles, tricycles and other humanly powered
12 vehicles within the scope of the invention and including an
13 outline of an automatic transmission according to an embodiment
14 of the invention;
Fig 2. is a diagrammatic view of an automatic transmission
16 according to an embodiment of the invention;
17 Fig. 3 is a longitudinal section through an automatic
18 transmission according to an embodiment of the invention;
19 Fig. 4 is a graph illustrating a step-action shifting
function according to an embodiment of the invention;
21 Fig. 5 is an elevation of a shifting mechanism detail seen
22 in Fig. 3 by viewing cam 80 and associated parts in an axial
23 direction from right to left; .
24 Fig. 6 is a diagrammatic view of a detail of Fig. 5 shown
in a dynamic manner according to an embodiment of the invention;
26 Fig. 7 is a graph illustrating hysteresis in gear shif tiag
27 according to an embodiment of the invention;.
28 Fig. 8 and 9 are elevations of a ratchet shown respectively
29 in an activated condition and in a disabled condition, such as
sees in Fig. 3 at 48 in an axial direction;
31 Fig. 10 is a view of a one-way clutch according to an
32 embodiment of the invention, as seen in Fig. 3 at 101 in an axial
33 direction from right to left;
34 Fig. 11 is an elevation of auxiliary planetary gearing
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1 according to an embodiment of the invention, as seen in Fig. 3
at 110 in an axial direction from right to left;
gig. 12 is a longitudinal section of a shift position
arrester according to an embodiment of the invention as a
5 modification of Fig. 3s
g gig. 13 is a longitudinal section and block diagram of an
? electromechanical transmission according to a further embodiment
g of the invention, and
g Fig. 14 is a diagrammatic view of a derailleur type of
automatic transmission according to a further embodiment of the
11 invention.
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1 Modes of Carrying Out TheInvention
2 gig. 1 is a side view of a relevant potion of a bicycle 10,
3 representative of bicycles, tricycles and other humanly powered
4 vehicles within the scope of the invention.
gig. 1 shows part of the vehicle frame 12 including the so-
b called seat tube 13 on which the seat post (not shown), Which
7 carries the seat or saddle (not shown), is adjustably mounted by
8 the seat lug (not shown). The seat tube 13 is fortified by the
9 seat stays 14 on which the rear wheel axle 15 and thereby the
rear wheel is mounted with the aid of the chain stays 16 and 17
11 and a pair of wheel mounts 18.
12 Also visible in Fig. 1 is the crank axle 20 rotating in the
13 familiar bearing where the seat tube 13, downtube 19 and chain
14 stays 16 and 17 meet, one of the two pedals 21 and the two crank
arms 22 which drive the so-called chain ring 23 and thereby the
16 drive chain 24 which in turn rotates the chain sprocket 25 for
propulsion of bicycle 10.
1g Also seen in Fig. 1 is part of a caliper brake 26 acting on
19 the rim 27 of the rear wheel 28 and being representative of a
manually actuable braking system for the bicycle or other humanly
21 powered vehicle.
22 Other more or less significant parts not shown in Fig. 1
23 include the familiar top tube in a men's bicycle or the
24 equivalent cross-bar structure in.a ladies' bicycle that extends
between the seat tube 13 and the front head tube (not shown).
26 That cross-bar or top tube is joined by the downtube 19 in
27 mounting the front head tube in which the handlebar stem (not
28 shown) is mounted for steering of the bicycle by angular movement
29 of the front wheel (not shown) which is mounted between a pair
of fork blades of the so-called fork that extends from the lower
31 end of the handlebar stem.
32 Fig. 1 diagrammatically indicates an automatic transmission
33 according to an embodiment of the invention at 30 With reference
34 to the remaining drawings and to the following description.
Within the scope of the invention. the bicycle may have a
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1 front-wheel drive, instead of the rear-wheel drive shown in Fig.
2 1, or both rear wheels may be driven in the case of a tricycle,
3 for instance.
4 In the embodiment of Fig. 1, the crank arms 22 carry pedals
21 at their ends whereby the vehicle is humanly powered through
6 a rider's body, including legs and feet. In this respect,
7 bicycles and other vehicles with manually powered cranks are also
8 known and are within the scope of the invention in terms of
9 utility of the disclosed automatic transmission system.
Manually actuated multi-speed transmissions that may be
11 automated pursuant to the subject invention are apparent from the
12 following patents:
13 US Patent 832,442, by J. Archer, issued 2 October 1906, for
14 Variable Speed Gear;
US Patent 2,301,852, by W. Brown, issued 10 November 1942,
16 for Epicyclic Variable Speed Gearing;
17 US Patent 3,021,728, by Keizo Shimano, issued 20 February
18 1962, for Three Stage Speed Change Mechanism for a Bicycle; and
19 Swiss Patent 258,751, by Hans Schneeberger, issued 15
December 1948, for a three-speed transmission for bicycles.
21 This prior-art literature contains some of the sun gear,
22 planet gear and related terminology used also in the present
23 disclosure and in the description of the accompanying drawings.
24 Basically, the subject invention automatically senses output
power torque of a shiftable bicycle transmission. The subject
26 invention thus avoids the disadvantages of the speed-sensitive
27 bicycle transmission mentioned above by way of background. The
28 subject invention thus truly assists the cyclist in automatically
29 shifting the bicycle's transmission whenever the torque necessary
for smooth operation in any uphill, downhill or level operation
31 of the bicycle so requires.
32 The invention automatically converts sensed output power
33 torque to transmission shifting motion, and automatically shifts
34 the shiftable transmission by automatically applying such
transmission shifting motion to the transmission shifting element
36 of that shiftable bicycle transmission without waiting for a
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1 speed change and without subjecting the cyclist to overexertion.
2 Fig. 2 diagrammatically shows an embodiment of the invention
3 that applies these principles. Figs. 3 and 13 by way of example
4 shoal a couple of related embodiments of the invention.
In particular, 30 is an automatic transmission having two
6 planetary systems 31 and 32, each having a sun gear 33 or 34 on
7 or around the rear wheel axle 15 shown in Figs. 1 and 3 and
8 symbolically also in Fig. 2. Sun gear 33 is keyed to shaft 15,
9 such as shown at 39 in Figs. 3 and 13. Planetary systems 31 and
32 also have planet gears 35.or 36 around the corresponding sun
11 gear 33 or 34 and meshing therewith. Each of these planetary
12 systems also has a ring gear 37 or 38 internally meshing with the
13 corresponding planet gears 35 or 36. The ring gear 38.of the
14 second or sensor planetary system 32 carries the wheel hub 40 to
Which the spokes 41 of the rear wheel 28 are attached, such as
16 via spoke spider anchors 42. Of course, within the scope of the
17 invention, the part 40 may symbolize other kinds of driven wheel
1g systems of humanly powered vehicles.
1g The automatic transmission 30 in Fig. 2 includes a first
ratchet 43 that connects the humanly powered sprocket 25 at the
21 input of the transmission 30 to the internal ring gear 37 of the
22 first planetary system 31, except when it is free-wheeling, such
23 as mentioned below. That transmission 30 also includes a second
24 ratchet 44 that interconnects the planet gears 35 and 36 of the
two planetary systems 31 and 32, except when it is free-wheeling,
26 such as also mentioned below. Transmission 30 further includes
27 a third ratchet 46 that can be disabled by the gear shift
28 mechanism, as indicated in the first set 47 of block positions
29 l, 2, 3 shown in Fig. 2, assuming a three-speed transmission by
way of example. The transmission 30 moreover includes a forth
31 ratchet 48 that also can be disabled by the gear shift mechanism,
32 as indicated in the second set 49 of block positions l, 2, 3
33 shown in Fig. 2. If enabled, the third ratchet 46 connects the
34 sprocket 25.to the planetary gears 35 of the first planetary
system 31. Alternatively or additionally, the fourth ratchet 48,
36 if enabled, either connects the sprocket 25 via the first ratchet
37 43 or connects the ring gear 37 to the planet gears 36 of the
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1 second planetary system 32, for the various shift positions.
2 In the embodiment of Figs. 2 and 3, the first and second
3 ratchets 43 and 44 are mechanically interconnected through the
4 internal ring gear 37 of the first planetary system 31. That is
a practical mechanical arrangement in some embodiments, but that
6 ring gear could, for instance, be internal of a common structure
7 of both the first and fourth ratchets 43 and 48. In other words,
8 both the first and fourth ratchets 43 and 48 could be
9 interconnected directly as long as they are also connected to the
ring gear 37, such as for transmission of human power through the
11 first planetary system 31 in certain shift positions. Also
12 within the scope of the invention, a similar arrangement is
13 possible for the second and third ratchets 44 and 46, which could
14 be interconnected directly as long as they are also connected to
planet gears 35 of the first planetary system 31.
16 As far as gear shitting is concerned, blocks 1 of the first
17 and second set of blocks 47 and 49 are shown in solid outline,
1g indicating that both second and forth ratchets 46 and 48 are
19 disabled in the first shift position (1) of the automatic
transmission. Accordingly, the humanly powered sprocket input
21 25 drives the wheel hub 40 through the ratchet 43, ring and
22 planet gears 37 and 35 of the first planetary system 31, and
23 through the ratchet 44 and the planetary gear 36 and ring gear
24 38 of the second planetary system 32. This shift position (1)
thus may serve to provide low-speed operation with high torque
26 for the bicycle or other humanly-powered vehicle.
27 Block position 2 is still solid in the first set of blocks
28 47 fox the third ratchet 46, whilst block 2 is dotted in the
29 second set of blocks 49 for the fourth ratchet 48, indicating
that the third ratchet 46 is still disabled, while the forth
31 ratchet 48 is not disabled, but is active or enabled in the
32 second shift position (2) of the automatic transmission.
33 Accordingly, the humanly powered sprocket input 25 drives the
34 wheel hub 4C) through the first ratchet 43, enabled fourth ratchet
48 directly or via ring gear 37 of the first planetary system 31,
36 and through the planetary gears 36 and ring gear 38 of the second
37 planetary system 32; the ratchet 44 being free-wheeling at this
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1 point. This shift position (2) thus may serve to provide what
2 may be called a straight or direct drive, such as for a mid-
i speed, mid-torque kind of operation of the bicycle or other
4 humanly powered vehicle.
5 Conversely, the blocks 3 of the first and second set of
6 blocks 47 and 49 are shown in dotted outline, indicating that
7 both second and forth ratchets 46 and 48 are not disabled, but
g are enabled or active in the third shift position (3) of the
9 automatic transmission. Accordingly, the humanly powered
10 sprocket input 25 drives the wheel hub 40 through the ratchet 46,
11 planetary gear 35 and ring gear 37 of the first planetary system
12 31, and through the ratchet 48, planetary gear 36 and ring gear
13 38 of the second planetary system 32; the ratchets 4~. and 44
14 being free-wheeling at this point. This shift position (3) thus
may serve to provide a high-speed, low-torque kind of operation
16 for the bicycle or other humanly powered vehicle.
17 While both planetary gear systems 31 and 32 participate in
1g the power transmission from the driven sprocket input 25 to the
19 wheel 28 or wheel hub 40 output, depending on shift position, the
second planetary system 32 may be considered part of the torque
21 sensor system according to a preferred embodiment of the
22 invention, since the primary role of such second planetary system
23 in the gear shifting function of the automatic transmission 30
24 is to sense output torque of that transmission for automatic
shifting.
26 Accordingly, the second planetary system 32 is connected to
27 a torque sensor 51 shown in block diagram form in conjunction
2g with the remainder of Fig. 2, but being representative of or
29 including any apparatus that automatically senses output power
torque, such as indicated by the arrow 52, and that automatically
31 converts sensed output power torque to transmission shifting
32 motion in steps corresponding to shift positions, such as steps
33 1, 2, 3, of one or more transmission shifting elements, such as
34 indicated at 47 and 49 is Fig. 2.
As further indicated by dotted lines 54 and 56, the
36 shiftable transmission 30 is automatically shifted by
37 automatically shifting the transmission shifting element with the
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1 converted transmission shifting motion in steps, such as 1, 2,
2 3. in the case of a three-speed transmission.
3 In this respect, while separate sets of shifting blocks 47
4 and 49 have been shown is Fig. 2 for the ratchets 46 and 48,
respectively, there may in fact be one shifting element for the
6 entire transmission. as is generally the case in manually
7 actuated transmissions, such as those disclosed in the above
8 mentioned incorporated patents.
g In terms of Fig. 3, for example, the transmission 30 may
have an input rotor 60 that may mount the sprocket 25 for
11 application of human power to the transmission and hence to the
12 driven wheel 28. This rotor is coupled to pawls 59 which with
13 bias springs 61 are part of the first ratchet 43. The.secoad
14 ratchet 44, in turn, has pawls 62 spring biased at 63. Such
ratchets may be of a conventional type that permit one-way
16 operation for power transmission in one direction, and that are
17 free wheeling in the opposite direction or sense of rotation.
1g Accordingly, the humanly driven input rotor 60 drives the
19 bicycle 10 through first and second ratchets 43 and 44, via ring
gear 37 and planetary gears 35 of the first planetary system 31
21 and through planetary gears 36 and ring gear 38 of the second
22 planetary system 32. This represents the above mentioned shift
23 position (1) for low-speed operation with high torque.
24 The torque sensor 51 in the embodiment of Fig. 3 operates
through the sun gear 34 of the second planetary system 32 in
26 automatically sensing output power torque of transmission 30.
27 Such transmission has an end cover 66 keyed to the shaf t 15, such
28 as at 67, in order to be stationary relative to the hub 40 and
29 other moveable parts. The heart of the torque sensor in the
embodiment of Fig. 3 is a torque measuring spring 68 that is
31 anchored to end cover 66 by as annular spring housing structure
32 69. In principle. that spring may be a type of clock spring
33 having one or more turns or may in fact be a spring system
34 composed of ,several spiral or other types of springs . The spring
or spring system used at 68 can be adapted to the kind of load
36 or system employed or can even be personalized to the owner and
37 user of the particular bicycle, for optimum gear shifting
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1 comfort .
2 The inner end of spring 68 is connected to an annulus 70
3 connected by coupling 52 to the sun gear 34 of the second
planetary system. Both that annulus and that sun gear are
angularly moveable relative to shaft 15. Accordingly, torque
6 generated by the bicycle rider not only drives the bicycle wheel
7 28 through ring gear 38, but also tensions the spring 68 through
8 sun gear 34 of the second planetary system 32 thereby sensing
9 output power torque and storing energy for transmission shifting.
The invention automatically converts sensed output power
11 torque to transmission shifting motion and automatically shifts
12 the shiftable transmission 30 by automatically applying that
13 transmission shifting motion to a transmission shifting element.
14 By way of example, the shaft 15 may at least partially be hollow
cylindrical, and the transmission shifting element may be or
16 include a push rod 72 in that hollow shaft.
17 The push rod includes and is actuated by a push bar 73
1g riding on the face of a cam 74, which, for example, may be of an
19 axially acting type. A development of an essential portion of
cam 74 on a plane is seen in Fig. 4, and a frontal view of that
21 cam 74 is seen in Fig. 5, indicating alternative flat and sloped
22 sections 75, 76, 77, 78 and 79 of increasing or decreasing height
23 is axial direction, depending on the sense of rotation imparted
24 by the sun gear 34 of the second planetary system 32. A like set
of sections 75 to 79 preferably is provided on cam 74
26 diametrically opposite the first-mentioned set 75 to 79, such as
27 shown in Fig. 5.
2g The annulus 70 angularly moves cam 74 as measured output
29 power torque tensions and conversely relaxes spring 68. Cam
slopes 76 and 78 act on the push bar 73 and thereby on push rod
31 72 to shift gears among several positions, such as those
32 indicated as (1), (2), and (3) in conjunction with Fig. 2, for
33 instance.
34 Ia practice, an automatic shifting mechanism may overreact,
with torque exerted by the bicycle rider and shifting of gears
36 is effect "hunting" each other, manifesting itself in an annoying
37 continual up and down shifting of the automatic transmission.
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1 Within the scope of the invention, some form of damping could be
2 employed to alleviate the problem. However, embodiments of the
3 invention prefer provision of some hysteresis to avoid "hunting"
4 within the automatic transmission. In practice, such hysteresis
may be realized by a built-in reluctance of the automatic
6 transmission to shift gears.
7 By way of example, a shift control hub or cam 80 may be used
8 for that purpose, such as shown in Figs. 3 aad 5. Such cam may
9 cooperate with rollers 81 pivoted on pivot arms 82 or other cam
followers riding for iastance on the periphery of cam 80. Such
11 pivot arms may. for instance, be supported by hinge pins 83
12 anchored in the ring structure 69 shown in Fig. 3 as a spring
13 housing and support. A tension spring 85 may act on the roller
14 support a~ns 82 in order to tension rollers 81 into contact with
cam 80.
16 The cam 80 may be of a radially acting type wherein pairs
17 of cam protrusions or bumps 87 and 88 cooperate with rollers 81
18 to realize the desired reluctance or hysteresis of the shifting
19 mechanism to engage in senseless "hunting". As seen in Fig. 6,
for instance, a single cam follower 81 with a single pair of cam
21 bumps 87 and 88 could be used within the scope of the invention.
22 However, Fig. 6 can also be viewed as an enlargement of a
23 peripheral region of cam 80, which includes a like diametrically
24 opposed symmetrical peripheral region.
Fig. 6 shows phantoms of a roller or cam follower 81 as a
26 peripheral region of the cam 80 moves relative thereto. In the
27 illustrated embodiment, it is the cam that moves angularly, while
2g the cam follower staads still peripherally and only moves
29 radially in respoase to bumps 87 and 88. Fig. 6 is of a polar
coordinate nature, whilst its related Fig. 4 is of a Cartesian
31 character, wherein radial extent of cam 80 and height of cam 74
32 and are symbolized as h in terms of angular movement or
33 development d.
34 In Figs. 4 aad 5, zero degrees, 0°, are positioned in a mid
range that, for instance, may correspond to a shift position (2) ,
36 such as mentioned in conjunction with Fig. 2. Bumps 87 and 88
37 of cam 80 effectively reign in that mid position by preventing
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1 the automatic transmission from dwelling between shif t positions
2 and from shifting prematurely. In particular, bumps 87 and 88
3 effectively prevent the pusher bar 73 from dwelling on either cam
4 slope 76 or cam slope 78. Bumps 87 and 88 of cam 80 cooperate
in releasably retaining pusher bar 73 within the plus and minus
6 7° raage of the secoad flat 77 of cam 74 representing, for
7 example, shift position (2).
g By way of further example, the above mentioned shift
9 position (1) may correspond to the flat 75 of cam 74 and an
angular range between 30° and 23° counterclockwise of the mid
1l range represented by flat 77. The transmission shifting
12 mechanism has to overcame bump 87 before it can shif t either way
13 between shift positions (1) and (2). w
14 Conversely, the above mentioned shif t position (3) may
correspond to the flat 79 of cam 74 and an angular range between
16 30° and 23° clockwise of the mid range represented by flat
77.
17 The transmission shifting mechanism has to overcome bump 88
1g before it can shift from position (2) forward to position (3),
i9 or from such position (3) back to position (2).
In this respect, the preferred embodiment of the invention
21 introduces the desired hysteresis, as may, for instance be seen
22 from the graph of Fig. 7 representing the wheel 28 to pedal 22
23 ratio R as a function of torque T of wheel 28 and also as a
24 function of torque S of sensor spring 68. As may be seen from
Fig. 7 there is a hysteresis 190 between mid and high gears (2)
26 and (3) , and another hysteresis 19.1 between low and mid gears (1)
27 and (2) . Tension spring 85 and other parameters of the system may
2g be dimensioned for realization of optimum hystereses for various
29 given purposes.
Preferred embodiments of the invention thus provide stable
31 and accurate shifting of gears for superior comfort and
32 utilization of the human power of the bicycle rider.
33 Free-wheeling ratchets of the type of the first and second
34 ratchets 43;and 44 are well known. Mechanisms for alternatively
enabling and disabling ratchets are also known and may be
36 employed in automatic transmission 30 with the shifting element
37 72 (push rod) etc. actuating such mechanisms.
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1 In this respect, the humanly powered rotor 60 drives both
2 the first ratchet 43 and the shiftable third ratchet 46. In Fig.
3 3, these ratchets axe both internal ratchets wherein pawls 59 and
4 64 are internal to the array of ratchet teeth of these ratchets.
5 Plaaet gears 35 of the first planetary system 31 drive the
6 second ratchet 44, Which in Fig. 3 is an external ratchet wherein
pawls 62 are external to an array of ratchet teeth of that
g ratchet. This in effect accommodates the fourth ratchet 48 in
9 its design around the second ratchet 44.
10 In Fig. 3 the fourth ratchet 48 is an internal ratchet
11 wherein the array of ratchet teeth drive the pawls 164 as
12 indicated by arrows in Figs. 8 and 9, but under the control of
13 a ratchet shifter or pawl disabler 91. As seen in Fig. 3, pawls
14 164 are arranged in a slot of an output rotor 116 that may be a
15 spider for planet gears 36 of the second or torque sensing planet
16 system 32.
1~ Fig. 8 and 9 by way of example show partial cross-sections
18 of the fourth ratchet 48 which are also illustrative of possible
19 executions of the first, second and third ratchets shown in Fig.
3, except that the first and second ratchets 43 and 44 would not
21 have a ratchet shifter or disabler 90, 91, the configurations of
22 the first and second ratchets 43 and 44 would be mirror images
23 of the fourth ratchet, with the pawls driving the ratchet, and
24 the third ratchet 46 is an external ratchet as mentioned above.
The pawl bias springs are only shown as torque 165 in Figs.
26 8 and 9. The heart of each shiftable ratchet is a ratchet
27 shifter 90 for third ratchet 46 and a ratchet shifter 91 for
28 fourth ratchet 48. Such elements disable the ratchet 46 or 48
29 in their axial position such as shown in Fig. 9 for the ratchet
48, by depressing the active ends of pawls 164 away from the
31 correspoading ratchet teeth 93. Third and fourth ratchets 46 and
32 48 are thus disabled from transmitting any power in their
33 condition illustrated in Fig. 3.
34 Conversely, the ratchet shifters 90 and 91 in their axial
position, such as illustrated for ratchet 48 in Fig. 8, enable
36 the ratchet 46 or 48 by sufficiently clearing ends of pawls 64
37 or 164 to permit rotation of these pawls by their spring bias 65,
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1 165 until active ends of these pawls 64 or 164 are positioned for
2 engagement with the ratchet teeth 93 in one sense of rotation of
3 the ratchet 46 or 48.
4 Such shifting may. for instance, be effected with the above
mentioned cam 74 and a corresponding bias spring 95 acting
6 conversely on pusher bar 73 which, in turn, shifts the central
7 shifting rod 72 and thereby a pusher bar 96 for the ratchet
g shifter 90 and pusher bar 97 for the ratchet shifter 91. Passive
9 and active conditions of ratchets 46 and 48 are indicated by
solid and phantom illustrations thereof in Fig. 3 . Reference may
11 in this respect be had to Fig. 2, to shifting blocks 47 and 49
12 and to the operational description thereof. Within the scope of
13 the invention, ratchet shifters 90 and 91 may be of di-fferent
14 width or thicknesses for different shifting effects, such as
indicated by shifting blocks 47 and 49 in Fig. 2, for instance.
16 Within the scope of the invention, different configurations
17 or types of pawls may be used in the requisite ratchets, or
18 sprag-type or other forms of one-way clutches may be employed for
19 what is herein referred to as "ratchets."
According to an embodiment of the invention, input power
21 torque applied to the transmission is equalized by coupling each
22 foot of a bicycle rider to a pedal of the bicycle. To this end,
23 foot-to-pedal couplings from each foot of a bicycle rider to each
24 bicycle pedal may be associated with the automatic transmission.
One example of such foot-to-pedal couplings is seen at 99 and may
26 be representative of the familiar toe clips and toe straps of
27 racing bikes and other upscale bicycles or other pedal couplings
28 attached to riders' shoes. Such foot-to-pedal couplings aid
29 skilled, attentive riders to exert power not only on the downward
angular motion of the pedal, but also during other phases,
31 including upward motion and angular motion through tops and
32 bottoms of the pedalling cycles. In conjunction with automatic
33 transmissions pursuant to the invention, this in practice helps
34 to prevent erratic shifting of the automatic transmission.
Additionally or more typically alternatively, a preferred
36 embodiment of the invention adds an internal anti-erratic
37 shifting feature to its automatic transmission Which retards
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1 upshifts as compared to corresponding downshifts. By way of
2 example, a one-way type of clutch, such as shown in Fig. 10, may
3 be employed in or with the torque sensor 51 to retard
4 transmission upshifts relative to downshifts.
Such a one-way clutch 100 may, for instance, act on the sun
6 gear 34 of the second or sensing planetary- system 32 . The clutch
may ride on a cylindrical extension of that sun gear and may
g itself constitute or be included in an auxiliary sun gear 101
9 rotating on that cylindrical extension, such as seen in Figs. 3,
10 and 11.
11 The one-way clutch 100 may include unidirectionally biased
12 clutch elements or rollers 102. In the embodiment of Fig. 10,
13 the clutch has tapered cavities 103 having internal surfaces
14 parallel to axes of the gears and being open at the axial
extension of sun gear 34. Rollers 102 are located in these
16 cavities and are biased against that extension by springs 104
17 causing rollers 102, extension of sun gear 34 and auxiliary sun
1g gear 101 to bind during relative movement indicated by arrow 106.
1g Conversely, biased rollers 102 are able to disengage from that
bind during relative angular motion 107. Unidirectional clutch
21 100 thus is able to retard upshifts that would occur prematurely
22 during fluctuations of the pedalling power or erratically as a
23 reaction to spring-mass oscillations of the drive structure.
24 Clutch 100 or its sun gear 101 may be part of further
planetary gearing 110, such as shown in Figs. 3 and 11. Since
26 the second sun gear 112 covers the first sun gear 101 in Fig. 11,
27 reference need to be had to Fig. 10 for a showing of the clutch
2g 100 in such first sun gear 101.
2g Either an even or an odd number of planet gears may be used
in any planetary system herein disclosed. For example, Figs. 3
31 and 13 show sun gear systems 31, 32 and 110 that have an even
32 number of planet gears. On the other hand, Fig. 11 shows as odd
33 number of planet gears with the understanding that an even number
34 of planet gars may alternatively be employed.
In addition to its first sun gear 101, gearing 110 may
36 include the second sun gear 112 which may be keyed to shaft 15
37 to be relatively stationary. Such second sun gear 112 preferably
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1 is of larger diameter than the first sun gear 101. The
2 preferably smaller sun gear 101 has planet gears 113, and the
3 preferably larger sun gear 112 has further planet gears 114, each
4 being preferably of smaller diameter than each of the planet
gears 113.
6 Planet gears 113 and 114 are interconnected to rotate in
7 synchronism and are journalled between planet gears 36 and a
8 spider 116 of such planet gears 36 of the second or torque
9 sensing planetary system 32. Such spider may serve as an output
rotor of the second and fourth ratchets 44 and 48 and may be
11 present, even if the auxiliary gearing 110 is not used in any
12 different embodiment of the invention.
13 In particular, planet gears 114 have pivots 119 connected
14 to spider 116 and planet gears 36 of second planetary system 32
to revolve in synchronism therewith about their stationary sun
16 gear 112. Planet gears 113 are connected to these planet gears
17 114 to rotate in synchronism therewith and to angularly move
1g their sun gear 101 slowly in a direction 107 that is opposite to
19 the direction of rotation 106 of spider 116.
In the illustrated embodiment, the pitchline velocity of sun
21 gear 101 is proportional and opposite in direction to the veloci-
22 ty at 106 multiplied by the difference of radii of planet gears
23 113 and 114 divided by the radius of planet gear 113. According
24 to a preferred embodiment of the invention, gear ratios within
auxiliary gearing 110 are selected to assure that during each mi-
26 nimum torque quarter turn of each pedal 21, the clutch 100 in sun
27 gears 101 restrains the sun gear 34 and hence the angular move-
2g meat of cam 80 through coupling 52 so that the automatic trans-
29 mission cannot upshift as a result of such minimum torque phase.
The embodiment of the invention shown in Figs. 3. 10 and 11
31 retards upshif is without affecting dowashif ts.
32 In particular, as the cyclist applies torque through the
33 automatic transmission, the second sun gear 34 torques the sensor
34 spring 68 via coupling 52 which thereby stores energy, reaching
a point at Which cams 74 and 80 downshift the transmission via
36 shifting bar 73 and element 72. Two such downshifts are
37 illustrated in succession in Fig. 7 by downwardly pointing
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1 arrows. Auxiliary planetary gearing 110 and its clutch 100 have
2 no effect on such downshifting, inasmuch as the extension of the
3 sensing sun gear 34 then is angularly moving clockwise as seen
4 in Fig. 10 relative to the auxiliary sun gear 101 so that clutch
rollers 102 would move out of any locking position at surfaces
6 103 against the bias of springs 104.
7 Sensing spring 68 stores energy imposed thereto by sensed
g output torque. If the torque applied by the cyclist decreases,
9 such energy previously stored in sensing spring 68 tends to
angularly move the sensing sun gear 34 counterclockwise as seen
11 in Fig. 10. In the absence of clutch 100 this would effect
12 upshifting of the transmission via cams 74 and 80 whenever torque
13 applied by the cyclist decreases.
14 However, the auxiliary planet system 110 is turning its sun
gear 101 in the direction of arrow 107 as long as the bicycle is
16 going forward. Due to the action of clutch 100 neither the
17 sensing sun gear 34, nor its coupling 52 can go faster
18 counterclockwise than the auxiliary sun gear 101. In
19 consequence, upshifting via cams 74 and 80 is retarded until the
energy stored in or by sensing spring 68 balances with the sensed
21 output torque, whereupon upshifting occurs, such as indicated in
22 succession by upwardly pointing arrows in Fig. 7 for two shifting
23 operations.
24 The currently discussed embodiment of the invention meters
the stored energy of sensing spring 68 in the automatic
26 conversion of sensed output torque to transmission shifting
27 motion to the effect that spring-mass oscillations occurring in
28 the system are dampened, if not precluded, and that inevitable
29 fluctuations is bicycle operation, such as from driving torque
diminutioas during pedaling through peaks of the pedal rotations,
31 cannot eventuate erratic shifting or dithering of the automatic
' 32 transmission.
33 By way of example. stored energy in sensing spring 68 is
34 metered to ;retard upshif is in the shifting of the shif table
transmissions 30 and 230. In this respect, clutch 100 and
36 auxiliary planetary gearing 110 may be employed to meter the rate
37 at which sensing spring 68 releases its energy, such as disclosed
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1 above with the aid of Figs. 3, 10 and 11. In apparatus terms,
2 the bicycle output power torque sensor 51 may include a sensed
3 output torque energy storing device 68 and the output power
4 torque-to-transmission shifting motion converter 70, 74, 80
5 includes a stored energy metering device 101, 110. Such stored
6 energy metering device may be a unidirectional upshift retarding
7 device. such as in the form of or including one-way clutch 100.
g According to a further embodiment of the invention, the
9 automatic transmission may be arrested at a given shift position.
10 What may be termed a "manual shift arrester" 123 may be made to
11 act on part of the automatic transmission, such as on an element
12 of its torque sensor 51.
13 In this respect, Fig. 12 shows an auxiliary annulus 124
14 acting on the sensor annulus 70 via corresponding coupling
15 elements, such as pins 125 and corresponding cavities 126. The
16 number of cavities may correspond to the number of shifting
17 positions or flats 75, 77, 79 shown in Figs. 4 to 6.
1g Such coupling elements may be manually actuated. By way of
19 example, the kind of cable pull 53 used, for instance, in prior-
20 art manual transmissions may be used to retain the auxiliary
21 annulus 124 disengaged from the sensing system annulus 70 against
22 the bias of springs 128. The auxiliary annulus 124 may be
23 released, such as by release of the cable pull 53, whereupon the
24 bias of springs 128 will cause pins 125 to engage cavities 126
so that the sensing sun gear 34 is no longer able to rotate the
26 annulus 70 relative to stationary cover 66. The cable pull 53
27 is again actuated to pull the shift arresting elements 125 away
28 from the sensing annulus 70, when resumption of the automatic
29 shif tiag function of transmission 30 is again desired.
Within the scope of the invention, torque may be sensed
31 electrically and/or the automatic transmission may be operated
32 electromechanically. By way of example, Fig. 13 shows such an
33 electrified version. The mechanical portion of such
34 electromechanical transmission 130 may. for example, include the
sprocket-driven input rotor 60, first planetary system 31 and
36 ratchets 43, 44, 46, 48 coupled respectively to planet and ring
37 gears 35 sad 37, ratchet shifters 90 and 91, an output rotor 216
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1 similar to the above mentioned output rotor 116, but more
2 directly coupled to the bicycle wheel hub 40, and other
3 mechanical parts such as shown jointly in Figs. 3 and 13.
4 The electromechanical transmission 130 also includes an
electrical part which, for more rapid understanding, carries
6 reference numerals that are elevated by "100" relative to similar
7 if not equivalent mechanical parts in embodiments shown in Figs.
g 2 to 6. 10 and 11, for instance. Of course, this by way of
9 example, and not by way of limitation.
Torque pickup in Fig. 13 may include electric gages, such
11 as strain gages 134, picking up torque from shaft 15 which is
12 torqued by sun gear 33 against its restraints at opposite ends
13 of that shaft. Such strain gages preferably are mounted on
14 opposite sides of shaft 15 at 45 degrees to the shaft axis.
Bending moments of the shaft will thus be canceled and torsional
16 forces imposed by the sun gear 33 of the humanly powered
17 planetary system 31 can thus be made additive in an electronic
1g torque sensor 151 that may include a strain gage reference
i9 amplifier which in a manner known per se from strain gage
technology converts strain gage signals into a switching signal
21 indicative of sensed human power torque.
22 Such electric torque signal 171 may be equivalent to the
23 torque delivered by the annulus 70 shown in Fig. 3. In analogy
24 to the cammed arrangement 80 illustrated in Figs. 3 and 4 to 6,
the circuitry of Fig. 13 may include electronic circuitry 180 of
26 a conventional type that responds only to peaks in signal 171
27 whereby only peak torques are recognized. By way of example,
2g circuitry 180 may include a torque level discriminator employing
2g such conventional elements as Schmitt trigger circuitry, in order
to convert the torque signal 171 into a tri-stable switching
33. signal. Instability may be avoided by detecting only peak signals
32 in the sensed output torque, and a counter that counts out the
33 above mentioned cyclically occurring torque fluctuations may be
34 used in the circuitry, such as at 151 to prevent erratic
3 5 shi f ting .
36 The sensed torque signal 171 as processed through circuitry
37 180 is applied via a lead 173 to a switching circuit 174 that in
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1 analogy to shifting element 72 shown in Fig. 3 effects selective
2 switching of the third and fourth ratchets 46 and 48. To this
3 end, switching circuit 174 responds to the processed torque
4 signal occurring at 173 by supplying switching signals to ratchet
shifter actuators 196 and 197. By way of example, such actuators
6 may include solenoid drivers, and the switching circuit 174 may
7 include a solenoid driver selector which may in effect be a
8 shifting element analogous to the shifting element 72 in the
9 mechanical version of Fig. 3.
In this respect, solenoid driver 196 alternatively energizes
11 spaced electromagnets 200 and 201 having the ratchet shifter 90
12 for the third ratchet 46 located therebetween. Similarly,
13 solenoid driver 197 alternatively energizes spaced electromagnets
14 202 and 203 having the ratchet shifter 91 for the fourth ratchet
48 located therebetween. By way of example, solenoid driver 197
16 may be a high-low driver, shifting transmission 130 among high
17 and low gears, and solenoid driver 196 may be an intermediate
1g solenoid driver, shifting the transmission to and from an
i9 intermediate gear.
Accordingly, third ratchet 46 is switched to and is retained
21 in its disabled state by energization of electromagnet 200 via
22 driver 196. Similarly, fourth ratchet 48 is switched to and is
23 retained in its disabled state by energization of electromagnet
24 202 via driver 197.
Conversely, third ratchet 46 is switched to and is retained
26 in its enabled state by energization of electromagnet 201 via
27 driver 196. Fourth ratchet 48 is switched to and is retained in
2g its enabled state by energization of electromagnet 203 via driver
29 197.
According to an embodiment of the invention, the ratchet
31 shifters 90 and 91 are or include permanent magnets so that
32 electromagnets 200, 201, 202, 203, can be energized to either
33 attract or repel their corresponding ratchet shifter 90 or 91.
34 Preferably, ;solenoids or electromagnets 200 to 203 have soft iron
cores so that each ratchet shifter 90 or 91 will remain at the
36 last electromagnet that has attracted it, until its opposite
37 electromagnet is energized. In such case, the mentioned
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1 energization of electromagnets may not be necessary for retaining
2 a switched ratchet in a switched state, since the permanent
3 magnetism of a ratchet shifter 90 or 91 may perform such
4 retention on the soft iron core of the adjacent electromagaet.
In practice, the switching pattern illustrated by switching
6 blocks 47 and 49 may be implemented in solenoid driver selector
7 174 and solenoid drivers 196 and 197 to effect gear shifting in
8 a manner explained above with reference to Figs. 2 et seq.
9 Solenoid driver selector 174 may be progra,a~ed for that purpose
or for any other desired switching pattern.
11 The countervailing ratchet switching actions may be gives
12 a bistable character by the above mentioned circuitry 180.
13 Alternatively or additionally, bent springs 205 and 206~having
14 configurations similar to one of the bumps 87 and 88 illustrated
in Figs. 4 to 6 may be provided in order to enhance the bistable
16 character of each ratchet shifting operation. In this respect,
17 in the mechanical version of Fig. 3, the spring 95 provides a
18 sustained force to move ratchet shifters 90 and 91 until a
19 ratchet shifting operation has been completed. In the
electromechanical version, an extended electromotoric force or
21 EMF maybe provided by aaalogy and/or springs 205 and 206 may
22 serve to complete the motion of ratchet shifters 90 and 91,
23 respectively, during the short delays when pawls move among their
24 positions exemplified in Figs. 8 and 9. for instance.
In analogy to the manual shift arrester 123 such as shown
26 in Fig. 12, the embodiment of Fig. 13 may include a shift
27 arrester, such as in the form of a switch 223 between torque
28 sensor 151 and solenoid driver selector 174. Such switch is
29 normally closed or biased to its closed position wherein gear
shifting occurs in response to sensed output torque changes.
31 Alternatively, switch 223 is opened, such as by the type of
32 cable pull 53 shown in Fig. 12 or by another manually exerted
33 force 153. In this manner, supply of shifting signals to the
34 solenoid , drivers may be interrupted, whereby the
electromechanical transmission 130 is manually arrested in any
36 then prevailing shift position. Switch 223 may be released to
37 its closed position whereby automatic switching of transmission
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1 130 is resumed.
2 The automatic transmission 130 may be electrified with
3 batteries and/or the kind of generating system used for bicycle
4 lights.
The embodiments of Figs. 3 and 13 employ several ball,
6 needle or other bearings which may be of_a conventional type.
Although planetary gear or hub type integral transmissions
g have been shown in detail and are preferred, the principles of
9 the subject invention and of its embodiments of Figs. 2 etc. may
also be applied to derailleur type of shiftable transmissions.
11 By way of example, Fig. 14 shows an automatic transmission
12 230 wherein a derailleur type of transmission 231 is substituted
13 for the first planetary gear system 31 of gear type transmissions
14 30 and 130.
Derailleur transmissions are well known and include the
16 tension wheel and the jockey wheels (not shown) around the chain
1~ 24 at the rear wheel 28, and the freewheel and gear cluster (not
1g shown) in the area of sprocket wheel 25. The sprocket input again
19 has been shown as 25, as in Fig. 2.
The torque sensing and transmission shifting system,
21 including the secondary planetary system 32 and torque sensor 51,
22 again may be provided according to a preferred embodiment of the
23 invention; this time to (a) apply the rear wheel or output torque
24 152 of the derailleur transmission 231 to the wheel hub 40 and
to (b) sense such output torque and shift the derailleur, such
26 as indicated by dotted lice 154.
2~ Within the scope of the invention, a derailleur type of
28 transmission system may be electrified, such as in the manner
29 disclosed above with respect to Fig. 13. In either case, a
derailleur or derailleurs is or are shifted instead of the
31 ratchets 46 and 48.
32 Within the scope of the invention, the transmission may be
33 hybrid, such as either automatic and manual or automatic gear
34 type and derailleur manual.
Although the invention and its various aspects are herein
36 disclosed with the aid of detailed embodiments, the invention
37 clearly neither is limited to such details. nor to any disclosed
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1 modes of carrying out the invention. Rather, this disclosure and
2 also the following parts thereof reveal a broad applicability of
3 the invention and a variability going clearly beyond the elements
4 mentioned herein as an aid to an acquisition of understanding.
5 Accordingly, the exemplary term "such as" need to be thought as
6 being present before each specific or numerical statement or
7 indication.
g From one aspect thereof, the invention shifts a shiftable
9 bicycle transmission by automatically sensing output power torque
10 of that transmission, automatically converting sensed output
11 power torque to transmission shifting motion, and automatically
12 shifting that shiftable transmission with said transmission
13 shifting motion.
14 To this end, a shiftable bicycle driving power transmission
15 30, 130, 230 may have a transmission shifting element, such as
16 72, 154 or 174, and comprises a bicycle output power torque
17 sensor 51, 151, and an output power torque-to-transmission
1g shifting motion converter 68, 74, 180, having a output power
19 torque input coupled to the output power torque sensor, such as
20 at 52 or 171, and having a transmission shifting motion output
21 73, 173. The transmission shifting element 72, 174 is coupled
22 to the transmission shifting motion output of that converter.
23 The output power torque may be sensed mechanically, and the
24 output power torque sensor 51 may be a mechanical output power
25 torque sensor 34, 52, 68. Alternatively, the output power torque
26 may be sensed electrically, such as at 151 employing strain gages
27 134. The output power torque preferably is sensed inside the
2g transmission, and the output power torque sensor 51, 134, 151
29 preferably is inside the transmission 30, 130, 230.
A variable corresponding to the output power torque may be
31 developed in the transmission, and the output power torque is
32 sensed from that variable. The output power torque sensor 51,
33 151 may include sun gear 34, strain gages 134 or other means for
34 sensing a variable corresponding to the output power torque in
the transmission 30, 130, 230, and a spring 68, strain gage
36 reference amplifier 151, torque level discriminator 180 or other
37 means for sensing that output power torque from that variable.
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1 A planetary gear 32 may be included in transmission 30 or
2 230, and the above mentioned variable may be derived from such
3 planetary gear. The output power torque sensor 51 may be coupled
4 to that planetary gear, such as indicated at 52 in Figs. 2, 3 and
14. Such output power torque sensor 51 may be coupled to a sun
6 gear 34 of that planetary gear 32, or, the above mentioned
variable may otherwise be derived from such sun gear 34 of
g planetary gear 32.
g First and second planetary gears 31 and 32 may be variably
coupled in series in the transmission, and the above mentioned
11 variable may be derived from one of these planetary gears, such
12 as from the second planetary gear 32. The transmission may
13 include first and second planetary gears 31 and 32 variably
14 coupled in series, and the output power torque sensor 51 is
coupled to one of such planetary gears, such as to the second
16 planetary gear 32.
1~ The shifting of the transmission may include reversing
1g transmission of power torque through the first planetary gear,
i9 such as from the ring gear 37 to the planet gears 35 in one shift
position (e.g. when third and fourth ratchets 46 and 48 are
21 deactivated). and conversely from these planet gears 35 to that
22 ring gear 37 in another shift position (e.g. When third and
23 fourth ratchets 46 and 48 are activated as means for reversing
24 that transmission of power).
The above mentioned variable may impose a strain on an
26 element in the transmission, and .the output power torque may be
27 sensed from that strain. By way of example, the output power
2g torque sensor may include a strain gage 134 on an element in the
29 transmission, such as shown in Fig. 13. Such element may be a
shaft 15 on which strain is imposed, and strain gage 134 may be
31 mounted on that shaft.
32 Another example of such an element is the spring 68 shown
33 in Fig. 3 on Which strain is imposed, such as from sun gear 34
34 via coupling 52. The output power torque sensor 51 may include
a spring 68 coupled to part of the transmission 30.
36 A derailleur 231 and gears 32 may be included in the
3~ transmission, such as shown in Fig. 14, and output torque may be
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1 sensed from such gears 32. The derailleur may then be shifted
2 with the above mentioned transmission shifting motion, such as
3 indicated at 154 in Fig. 14, Which shows a derailleur 231 and
4 gears 32 between that derailleur and an output 40 of transmission
230. The output power torque sensor 51 is coupled to these
6 gears, such as at 52, and the transmission shifting element 154
7 is coupled to the derailleur. Gears 34, 36, 38 may be arranged
8 in a planetary system.
g The transmission may be shifted in upshifts and in
downshifts, and a hysteresis 190, 191 may be imposed on the
11 automatic shifting as between such upshif is and downshifts, such
12 as shown in Fig. 7. Upshif t shifters and downshift shifters may
13 include the cam 74 acting on shifting element 72 and ratchets 46
14 and 48, and means for imposing hystereses may include cam 80 with
bumps 87, 88, etc.
16 Energy of the sensed output torque may be stored, such as
17 in spring 68 mechanically or in a circuit 180 electronically, and
1g such stored energy may be metered in the automatic conversion of
19 sensed output power torque to transmission shifting motion. Such
stored energy may particularly be metered to retard upshifts in
21 the shifting of the shiftable transmission 30, 130, 230. By way
22 of example, such metered energy release may be effected by
23 auxiliary planetary gearing 110 with one-Way clutch 100, which
24 also may impose a hysteresis of sorts. Upshifts preferably are
retarded relative to downshifts. By way of example, upshif is are
26 retarded while converting sensed output power torque to
27 transmission shifting motion. Transmission 30, 130 may include
28 upshift shifters and downshift shifters 90, 91 and shift
2g retarders 87, 88, 100, 180.
Pursuant to a preferred embodiment of the invention, sensed
31 output power torque is automatically converted to the
32 transmission shifting motion in steps corresponding to shift
33 positions of the transmission, such as (1), (2), (3), and such
34 shiftable transmission is automatically shifted by automatically
shifting that transmission with such transmission shifting motion
36 in these steps. The output power torque-to-transmission shifting
37 motion converter of the transmission may include a step-action
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1 converter 74, 80. 180 having a stepped transmission shifting
2 motion output at 73 or 173.
3 Ia this or any other manner within the scope of the
4 invention, the automatic transmission preferably has distinct
shifting positions, such as (1), (2), (3), corresponding to
6 different output power torques, and such conversion of output
7 power torque preferably is automatically detained until the
g sensed output power torque has achieved a value corresponding to
9 a distinct shifting position of that transmission. The
conversion of output power torque is automatically released
1l whenever the sensed output power torque has achieved a value
12 corresponding to a distinct shifting position of the
13 transmission, and such shiftable transmission is automatically
14 shifted upon release of that conversion by applying a
transmission shifting motion to that transmission. In this
16 respect, the transmission shifting element 72, 174 has distinct
17 shifting positions corresponding to different output power
1g torques applied to the transmission, and the converter may have
19 a detent 87, 88 adapted to detain output power torque-to-
transmission shifting motion conversion and thereby shifting of
21 the transmission until sensed output power torque has achieved
22 a value corresponding to a distinct shifting position of the
23 transmission shifting element, such as also implemented by
24 circuit 180.
The transmission shifting element may be a translatory
26 transmission shifting element 72, and its output power torque
27 input is a rotary output power torque input 34, 52, 70, 74
28 coupled to an output power torque sensor 51, 68. The
29 transmission shifting motion output may be a translatory
transmission shifting motion output 73 coupled to that rotary
31 output power torque input. The traaslatory transmission shifting
32 element 72 may be coupled to that traaslatory transmission
33 shifting motion output 73.
34 The transmission typically has distinct lower and higher
shif tiag positions corresponding to different output power
36 torques, and the conversion of output power torque is
37 automatically detained until the sensed output power torque has
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1 achieved a value corresponding to a distinct shifting position
2 of that transmission. The conversion of output power torque is
3 automatically released whenever the sensed output power torque
4 has achieved a value corresponding to a distinct shifting
position of the transmission. Preferably, such conversion of
6 output power torque is detained and is thereafter released at a
7 hysteresis so that output power torque is released at different
8 shift points for shifts from a lower shifting position to a
9 higher shifting position than for shifts from a higher shifting
position to a lower shifting position, and such as shown by Way
11 of example in Fig. 7. The shiftable transmission is
12 automatically shifted at such different shift points.
13 Shift points for shifts from a lower shifting position to
14 a higher shifting position preferably are lower in teems of
output power torque than shift points for shifts from a higher
16 shifting position to a lower shifting position, such as seen in
17 gig. 7, for instance. The transmission shifting element 72
1g preferably has distinct lower and higher shifting positions
19 corresponding to different lower and higher output power torques,
respectively, applied to the transmission, ann the converter 74,
21 80 has a decent 87, 88, 100 adapted to detain output power
22 torque-to-transmission shifting motion conversion and thereby
23 shifting of the transmission at different shift points for shifts
24 from a lower shifting position to a higher shifting position than
for shifts from a higher shifting position to a lower shifting
26 position.
27 The shiftable bicycle transmission 30, 130, 230 may be
2g arrested in any shifting position. By way of example, a manual
29 shift position arrester 123, 223 may be coupled to the
transmission, such as by a coupling of the shift position
31 arrester to torque sensor 51, 151, etc.
32 This extensive disclosure with many examples in and from the
33 mechanical and electric arts demonstrates the broad scope of the
34 invention axed of its various aspects and embodiments, rendering
apparent or suggesting to those skilled in the art various
36 modifications and variations within the spirit and scope of the
37 invention.
