Gear-shifting mechanism controlled and commanded by a governing unit in an automatic controlled way

A gear shift mechanism in a transmission connecting a drive source to an output via a clutch. The gear shift mechanism acts on a plurality of gear pairs to select one thereof during a speed change when the clutch is disengaged. The gear shift mechanism has a hollow shaft which can be the input or output shaft of the transmission. One of the gears of the gear pairs are idly mounted on the hollow shaft and the other of the gears of the gear pairs are secured to the output shaft or a further shaft connected thereto. Alocating tube rotates with the hollow shaft and is slidable therein. The locating tube and hollow shaft have a plurality of angularly aligned radial holes and when one of the idler gears of the gear pairs is selected for engagement, the locating tube is displaced to align the radial holes therein with holes in the selected idler gear. Each of the radial holes slidably supports an engagement pin. An axially displaceable actuator within the locating take engages inner ends of the engagement pins and displaces the pins to extended positions in driving engagement with the idle gear of the selected pair.

FIELD OF THE INVENTION 
The present invention relates to a gear-shifting mechanism controlled and 
driven by a governing unit automatically or manually. This mechanism 
actuates a respective one of a number of constantly meshed gear pairs by a 
shifting operation. One gear of each gear pair is on an input shaft and 
the other gear is on an output shaft. 
BACKGROUND 
Gear pair shafting mechanisms in a gear box are universally utilized in the 
form of a hub which is displaced on a splined shaft to engage a selected 
gear. The shifting mechanism can have a rotation synchronizing device to 
provide for the engagement without clashing of the teeth. During a speed 
change, i.e. a change of the selected gear pair for the operation, which 
change is made with the machine or vehicle running or moving, a 
synchronization of the movements of the parts of the transmission is 
required. 
These mechanisms have been largely utilized in mechanical industries and in 
automotive transmissions. Mechanisms with synchronizing rings are largely 
used and well known. An example of such shifting mechanisms with 
synchronizing rings is disclosed in a publication of the SAE (Society of 
Mechanical Engineers) under number 680008, published in January, 1968. 
SUMMARY OF THE INVENTION 
The object of this invention is to provide a shifting mechanism actuating a 
clutch between the motor (engine) an d the transmission during gear 
shifting when a particular gear pair is selected. The shifting mechanism 
releases the clutch in order to permit the selection of the particular 
gear pair and when the selection of said gear pair is made, the shifting 
mechanism synchronizes the rotation of the rotary members which are active 
during operation and when synchronization is achieved, the shifting 
mechanism provides for the engagement of the selected pair for operation. 
Once this step is attained, the shifting mechanism causes the clutch 
between the motor (engine) and the transmission to be engaged and thus 
rotation and torque are now transmitted through the transmission to the 
output.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 shows a first embodiment of the gear shifting mechanism with 
constantly meshed gear pairs and its actuation means. The transmission has 
a main portion containing the constantly meshed gear pairs. One of the 
gears of each gear pair is slidably mounted on the hollow shaft 2 as 
idlers. These gears are designated by reference numerals 201, 202, 203, 
204, 205, and 206. Mounted on a shaft 34 parallel to said hollow shaft 2 
are the second gears of each gear pair constantly in mesh with gears 
201-206. These second gears are designated by reference numerals 211, 212, 
213, 214, 215 and 216 and are fixed to the shaft 34 to rotate therewith. 
Between the shaft 34 and the hollow shaft 2 is a gear shaft parallel to 
shafts 2 and 34 to enable reverse rotation for a specific gear pair. This 
arrangement of a rotation reversing shaft has been already employed in 
transmissions for vehicles in order to provide a reverse speed. Before the 
hollow shaft 2 as well as after the parallel shaft 34, many shafts as are 
necessary to the design can be present. The number of constantly meshed 
gear pairs depends upon the design and the application of the 
transmission. 
FIG. 2A shows a variation of the engagement and disengagement mechanism 
when actuated by a hydraulic or pneumatic system driven and governed by a 
governing unit 18 operating in conjunction with a relay and coil logic 54 
controlling an opening for the inlet of hydraulic fluid or compressed air. 
FIG. 3A shows a variation of the engagement and disengagement mechanism 
when actuated by an actuation system through an electromagnetic solenoid 
71 driven and governed by the governing unit 18 which acts on a relay 
logic 83 controlling the energization or de-energization of coil 75 of 
solenoid 71 through an electrical voltage source 84. 
FIG. 4 shows a machine having an electric motor 101 providing power, a 
clutch 102 between the motor and a transmission 103 with constantly meshed 
gear pairs a shifting mechanism 104 and a rotation and torque output means 
105. The clutch is actuated by an actuation mechanism forming part of the 
same shifting mechanism 104. Between the clutch 102 and the transmission 
103, there is a mechanical linkage element which can be a pair of pulleys 
106 coupled by a belt 107, or any other conventional rigid or elastic 
coupling means. 
FIG. 5 shows the shifting mechanism 104 mounted on an automotive vehicle 
provided with a clutch, the vehicle having a drive motor 121 which could 
be an internal combustion engine or other motor delivering power to the 
vehicle at variable speed. Between the motor and the transmission 123 
there is the clutch 122. The transmission contains the constantly meshed 
gear pairs and provides the torque output for the differential 128, 
through a universal joint 126 and drive shaft 127. The vehicle drive 
wheels 129 are driven from differential 128. Although the schematic 
representation in FIG. 5 shows a rear wheel drive vehicle, the inventive 
concept is equally applicable to front wheel drive vehicles. Only the 
linkage between the output means 125 of the transmission 123 and 
differential 128 is changed. 
The invention seeks to provide a construction for coupling gears so that 
the shifting mechanism has one of its portions, that is, the engagement 
and selection portions mounted internally of a shaft or mounted in more 
than one shaft and this mechanism is driven through a governing unit 18 
automatically or manually. The mechanical portion of the shifting 
mechanism comprises parts mounted internally in the shaft, the actuating 
parts, a chain or belt transmission, and electric actuator motors. Between 
the electric motors and the governing unit 18, are electro-electronic 
devices or servo-actuators 17 providing power to the motors as the 
governing unit 18 sends decoded signals to these servo-actuators so that 
these cause the electric motors to act in a sequence provided by the logic 
of the governing unit. 
FIG. 6 shows in a schematic way, the hierarchy of the drives. The governing 
unit 18 is physically constituted by electronic hardware based on 
microprocessor technology. The governing unit 18 has a memory containing a 
program (software) 18A managing all the events of driving, control, 
actuating and sensing for the shifting mechanism. The managing hardware 
and software portions 18A of the governing unit 18 in the case of the 
application shown in FIG. 4, can be included in a central processing unit 
(CPU) of a COMPUTERIZED NUMERICAL CONTROL (CNC) or inside the central 
processing unit of a PROGRAMMABLE LOGIC CONTROLLER (PLC) which can be 
fitted on the machine on which the shifting mechanism is being applied. 
This governing unit 18 receives pulses to operate, manually by action of 
the operator, through the lever 120 or other data input means, or 
automatically through the software 18A which is the managing program 
containing all the logic for automatic operation. This program is stored 
in the governing unit 18 and operates the electronic servo-actuator 
assembly 17 of the actuating motors. Each electronic servo-actuator 
actuates a respective motor in the following way: clutch actuating motor 
33 is actuated by the electro-electronic actuator 33A (the release and 
engagement of the clutch can be effected by any hydraulic or pneumatic 
system), the synchronization actuating motor 16 is actuated by the 
electro-electronic actuator 16A, and the actuation motor 15 for selection 
of the gear pair is actuated by the electro-electronic actuator 19A. For 
release and engagement of the clutch and its modulation, the actuating 
mechanism can comprise hydraulic or pneumatic actuators, controlled by 
governing unit 18 with a logic suitable for the application. The 
engagement motor 19 as well as the entire engagement mechanism can have 
other constructions, such as hydraulic or pneumatic piston as in FIG. 2 or 
a mechanism comprising an electromagnetic solenoid and a spring as in FIG. 
3. Said motors as well as the servo-actuators 17 thereof can be of 
electric direct current or electric alternating current type. Lastly, the 
system is completed in a closed loop through a set of sensors 37 for 
feedback of positioning, rotation and load data. 
The mechanical portion of the shift mechanism 104 has three basic 
constructions, identical as to the location of the gear pairs, but with 
three variants of the engagement mechanism of the located and selected 
gear pairs. The variants are shown in FIGS. 1, 2A and 3A and are described 
hereafter. 
The first embodiment of the mechanical portion of the shift mechanism 104 
is disclosed in detail for selection of the gear pair or selection of 
speed and engagement of said speed. This first embodiment utilizes the 
engagement motor 19 as shown in FIG. 1. 
This first embodiment comprises a locating tube 1 sliding on the hollow 
shaft 2 of the gears to be engaged. The constantly meshed gear pairs of 
the transmission 103, 123 of FIGS. 4 and 5, have one of the gears of the 
pairs mounted idly on the hollow shaft 2 and the corresponding gears of 
the constantly meshed gears mounted on a shaft 34, parallel to the hollow 
shaft 2, so as to rotate therewith as if the parallel shaft 34 and said 
gears were integral. The locating tube 1 can have at the end thereof a 
plurality of radial holes for example, five, the number of radial holes 
depending on the mechanical torque transmitted through the transmission. 
FIGS. 7, 7A show a gear which rotates idly on the hollow shaft 2 and forms 
part of one of the constantly meshed gear pairs of the transmission 103, 
123. These gears have external teeth 150 which transmit torque and 
rotation. Each constantly meshed gear pair has a respective transmission 
ratio in conformity with the plurality of the constantly meshed gear 
pairs. Said gears which rotate idly on the hollow shaft 2 have internal 
teeth 4c which can be coupled to teeth 4a of the engagement pins 4. At 
both sides of internal teeth 4c, in the inner hole of the idler gear, 
sliding bearings 152 are disposed which allow the gear, when it is not 
engaged by the engagement pins 4, to rotate idly on the hollow shaft 2 
with minimum friction and with minimum energy dissipation and in a 
balanced way since said sliding bearings 152 are mounted on both sides of 
the internal teeth 4c. The spacing of internal teeth 4c and the dimensions 
thereof permit coupling with teeth 4a of the engagement pins 4. Said gears 
which rotate idly on hollow shaft 2 form respective gear pairs with the 
gears which are engaged on the parallel shaft 34 and are constantly meshed 
wherewith pair by pair. Hollow shaft 2 has, for each gear of the 
constantly meshed gear pair which is mounted thereon, a row of radially 
disposed holes equally spaced and centered exactly around the radial 
centerline 151 of each gear mounted idly on the shaft 2. It is through 
these holes of the hollow shaft 2 that the engagement pins 4 will transmit 
torque and rotation of the hollow shaft 2 to the gear of the constantly 
meshed pair selected for engagement. In order to have a perfect location 
position in the movement of selection of the constantly meshed gear pair, 
the selection mechanism is provided with a positioning sensor 37b which 
can be linear or rotary and which senses the position of the locating tube 
1 and informs the governing unit 18 so that it monitors and drives the 
system. 
FIGS. 8, 8A show a gear engaged on the parallel shaft 34 and wherein the 
central hole of the gear is not circular but rather has a polygonal shape 
160. In FIG. 8A, the polygonal hole 160 has three sides, but it can have 
four or more sides. The advantage of this system is that it does not need 
to use keys or internal teeth in the gear for attachment with the 
corresponding shaft. Parallel shaft 34 also is not circular and in the 
portion thereof on which the gears of the constantly meshed pairs are 
mounted, the shaft 34 has exactly the same outer polygonal shape 160 as 
the gear. Therefore, the gear and the shaft are always attached for 
transmitting rotation and torque. The locating tube 1 has the function of 
selecting the speeds or of selecting the gear pair to be engaged. In order 
that the locating tube 1 effects the selection, it has to slide within the 
hollow shaft 2 so that the centerline 151 of the radial holes which 
contain the engagement pins 4 is positioned in the center of the internal 
teeth 4c of the gear of the gear pair which will be engaged. In order that 
hollow shaft 2 always rotates integrally with the locating tube 1, both 
are attached through a key 3 permitting relative axial sliding 
therebetween. In the locating tube 1 the number of engagement pins 4 is 
the same as the number of holes, which pins serve to connect the gear of 
the selected pair to the hollow shaft 2 and transmit torque and rotation 
while all remaining gear pairs which are constantly meshed, rotate idly, 
that is, without transmitting rotation and torque. The engagement pins 4 
as shown in FIG. 1B, are radially mounted at the end of the locating tube 
1 with equal spacing as shown in FIG. 1(A)1. Engagement pins 4 have at 
their engaging end, teeth 4a which engage the internal teeth 4c of the 
selected gear. In FIGS. 1A and 1B, each engagement pin 4 is represented 
with only one tooth 4a, but it can be provided with one or more teeth 4a 
to be coupled with the internal teeth of the gears 4c. At the other end of 
the engagement pin 4, it has a sliding inclined plane 4b with a suitable 
angle to slide over an actuating tip 5. Engagement pins 4 are engaged on 
the actuating tip 5 by guides 6 shown in FIG. 1(C)1-1(C)3. Engagement pins 
4 have slots 6A receiving the guides 6. In the clutching movement, when 
the engagement pins 4 are actuated outwardly against the gear internal 
teeth 4c, engagement pins 4 bear on the actuating tip 5. In the 
disengagement movement, when the engagement pins 4 move out of the 
internal tooth 4c, said engagement pins are pulled by the guides 6 of the 
actuating tip 5 through the slots 6a thereof and through the surface 6b of 
said slot 6a which is T-shaped. Guides 6 of the actuating tip 5 can be 
slipping or rolling guides. T-shaped slot 6a keeps the engagement pin 4 
attached to the actuating tip 5 so that the tip 5 is extracted for 
disengagement. Alternatively, retracting springs can be used to retract 
pins 4, in which case a "T"-profile is no longer necessary. The springs 
are disposed in a radial fashion like the pins, always applying the 
retraction force on the engagement pins 4. Once the actuating tip 5 is 
retracted, engagement pins 4 are also retracted by the springs. When the 
engagement pins 4 are totally retracted with the locating tube 1, they 
will have a diameter smaller that the diameter of hollow shaft 2 so that 
they can move with locating tube 1 to select a new gear pair without said 
engagement pins 4 rubbing or interfering with the internal bore of hollow 
shaft 2 during the selection movement of locating tube 1. The selection 
movement is monitored by a positioning sensor 37b to ensure accuracy of 
said positioning. The movement of location and selection of the gear pair 
to be selectively engaged is made by a lug nut 7 engaged in locating tube 
1 by a roller bearing 8 to cause the locating tube 1, which is rotating 
with hollow shaft 2, to slide within hollow shaft 2 and to selectively 
locate the gear of the gear pair to be engaged. Lug nut 7 does not rotate 
with locating tube 1 because of the roller bearing 8 but, through this 
roller bearing 8 axially displaces locating tube 1 to the position for 
selection of the particular gear pair to be engaged. The part which makes 
lug nut 7 slide to displace locating tube 1 into a selection position is a 
spindle 9 which is supported by a housing 10 of the transmission, through 
two roller bearings 11, 12. The spindle 9 is spline connected to a 
synchronizing pulley 13 or a toothed pulley which, through a synchronizing 
toothed belt or chain 14 is driven from a direct or alternating current 
servomotor 15. This motor 15 is driven by an electro-electronic apparatus 
for power transmission referred to as a servoactuator 15a which is 
schematically depicted in FIG. 6. Servo-actuator 15a actuates motor 15 to 
drive the belt 14 of the governing unit 18. The clutching movement or the 
movement of the engagement pins 4 is effected through longitudinal 
displacement axially of locating tube 1 and relative to this locating tube 
1, of the actuating tip 5 to which engagement pins 4 are engaged through 
slots 6a in the bases of said engagement pins 4, by the guides 6 of said 
actuating tip 5. The clutching movements of said engagement pins 4 are 
radial and perpendicular to the axial displacement of the actuating tip 5. 
The actuating tip 5, besides rotating together with said locating tube 1, 
and being displaced within locating tube 1 axially to cause the location 
and selection movement, has also a relative axial movement with this 
locating tube 1, which axial movement is inherent to the actuating tip 5 
which is independent of locating tube 1. This axial movement produces 
radial movement of engagement pins 4 through an end cone of the actuating 
tip 5 and through inclined plane 4b of the engagement pins 4. Actuating 
tip 5 rotates together with locating tube 1 since it is engaged therewith 
by engagement pins 4. The positioning accuracy of the actuating tip 5 to 
effect the engagement or disengagement operation is ensured by the 
monitoring by the positioning sensor 37a. As a first alternative, 
according to FIG. 1, so that the actuating tip 5 effects axial movement 
and promotes radial movement of engagement pins 4 into locating tube 1 and 
engages the gear of the selected gear pair, said actuating tip 5 is 
axially displaced by an extended screw 25 which is not rotated but is only 
axially displaced to displace actuating tip 5 through a roller bearing 31. 
Extended screw 25 is not rotated since it is engaged in an anchoring tube 
27 through a key 27a and the anchoring tube is engaged with a cap 28 which 
in turn is secured to the transmission housing 10. An extended nut 24 
which is mounted within locating tube 1 and axially therewith does not 
rotate with the tube since there is a roller bearing 30 therebetween that 
permits extended nut 24 to be translated axially within locating tube 1. 
By rotating independently of locating tube 1, extended nut 24 causes the 
extended screw 25 to move axially within anchoring tube 27, whereby 
extended screw 25 axially displaces actuating tip 5. Extended nut 24 is 
rotated by a turning tube 22 through key 23. Turning tube 22 has its own 
rotational movement. Turning tube 22 does not displace axially in relation 
to the transmission housing 10 since it is attached to the transmission 
housing 10 through roller bearing 29. Extended nut 24 is always attached 
to turning tube 22 through key 23 as the turning nut 24 which is mounted 
within locating tube 1 moves axially therewith. Extended nut 24 axially 
travels within turning tube 22 as locating tube 1 is displaced since 
extended nut 24 is attached to locating tube 1 by roller bearing 30. 
Turning tube 22 rotates by means of synchronizing or toothed pulley 20 
which is engaged with said turning tube 22 through key 21. Synchronizing 
or toothed pulley 20 is driven through a synchronizing belt or chain 32 
which is rotated from the direct or alternating current motor 19 through 
synchronizing or toothed pulley 20. Extended nut 24 rotates and thereby 
actuates extended screw 25 to be axially displaced rightwards or 
leftwards, depending upon the turning direction imposed by the direct or 
alternating current motor 19. Therefore, with movement of actuating tip 5 
caused by the axial movement of extended screw 25 to which said actuating 
tip 5 is attached through roller bearing 31, engagement pins 4 engage and 
disengage the gear of the selected gear pair. 
In a second embodiment, in accordance with FIG. 2, in order for actuating 
tip 5 to carry out the axial movement and produce radial movement of 
engagement pins 4 within locating tube 1 and engagement of the gear of the 
selected gear pair, the actuating tip 5 is displaced axially by an 
actuation piston 40 which does not rotate since it forms part of an 
actuation cylinder 41. The actuation piston 40 and the actuation cylinder 
41 are relatively movable axially and can not rotate in relation to one 
another as they are engaged through a key 42. Since the actuating tip 5 is 
attached to engagement pins 4 and this assembly rotates with hollow shaft 
2, in order for non-rotating actuation piston 40 to displace actuating tip 
5, the actuation piston 40 is attached to the actuating tip 5 through 
roller bearing 43 which permits transmission of the axial movement from 
the actuation piston 40 to the actuating tip 5. Actuation piston 40 moves 
axially within actuation cylinder 41 by hydraulic or pneumatic action, and 
the actuation movement of actuation piston 40 is such that engagement pins 
4 can engage teeth 4a in internal teeth 4c of the gear of the selected 
pair, and the hydraulic fluid or compressed air will be sent to an 
actuation chamber 44 of actuation cylinder 41 through actuation orifice 45 
in the actuation piston 40. A deactuation chamber 46 is connected, free of 
pressure, to a tank or outlet 56. In order for engagement pins 4 to be 
retracted to disengage teeth 4a from internal teeth 4c of the gear of the 
previously selected gear pair, hydraulic fluid or compressed air is 
supplied to deactuation chamber 46 through deactuation orifice 47 in the 
actuation piston 40, and actuation chamber is connected, free of pressure 
to the tank or outlet 56. Engagement pins 4 are pulled inwardly of 
locating tube 1 to enable the actuating tip to be displaced for subsequent 
gear selection. Actuation cylinder 41 does not rotate with hollow shaft 2 
but rather it is displaced axially therewith during the movement for 
selection of the gear pair to be operative. Actuation cylinder 41 is 
attached to hollow shaft 2 through roller bearings 48 which allow for 
relative rotation therebetween but not for relative axial movement 
therebetween. Actuation cylinder 41 has an extension 49 which is connected 
to an anchoring tube 50. Extension 49 enters and exits from anchoring tube 
50 during selection movement of the gear pair and anchoring tube 50 is 
engaged in the housing 10 of the transmission and therefore is secured 
against movement. A key 51 attaches the anchoring tube 50 to extension 49 
of actuation cylinder 41 whereby actuation cylinder 41 cannot rotate 
relative to housing 10 but is axially movable relative to housing 10. The 
extension 49 also houses within it, actuation and deactuation ducts 52 and 
53 which carry hydraulic fluid or compressed air. Flow of compressed air 
or hydraulic fluid into actuation cylinder 41, to effect actuation of 
actuation piston 40 and consequently to effect engagement and 
disengagement of the selected gear pair through engagement pins 4 is 
achieved by actuation and deactuation ducts 52 and 53. Governing unit 18 
acts on a relay and coil logic 54 which directs hydraulic fluid or 
compressed air from a source 55 of hydraulic fluid or compressed air to 
the actuation and deactuation ducts 52 and 53 with return to zero 
pressure, and tank 56. 
As a third embodiment, according to FIG. 3, in order for actuating tip 5 to 
effect axial movement and produce radial movement of engagement pins 4 
within locating tube 1 and engage the gear of the selected gear pair, the 
actuating tip 5 is axially moved by an actuation pin 70 which does not 
rotate since it forms part of an actuating electromagnetic solenoid 71. 
The actuation pin 70 and electromagnetic solenoid 71 are relatively 
movable only axially and are secured for common rotation by a key 72. 
Since actuating tip 5 is attached to engagement pins 4 and this assembly 
always rotates with hollow shaft 2, in order for actuating pin 70, which 
does not rotate, to push or pull actuating tip 5, the actuating pin 70 is 
attached to the actuating tip 5 through a roller bearing 73 which permits 
transmission of axial movement from actuating pin 70 to actuating tip 5. 
Actuating pin 70 moves axially within electromagnetic solenoid 71 by 
mechanical or magnetic action through the effect of a spring 74, and the 
actuation movement of actuating pin 70 pushes engagement pins 4 to engage 
teeth 4a in the internal teeth 4c of the gear of the selected pair. During 
the actuation movement coil 75 of electromagnetic solenoid 74 is 
deenergized, and spring 74 displaces actuating pin 70 to effect engagement 
movement of actuating tip 5. In the meshed gear position, with all 
engagement pins 4 coupled to the selected gear, actuating pin 70 is 
retained by the action of spring 74 and by a mechanical lock 76. In order 
to disengage engagement pins 4 from teeth 4a of the internal teeth 4c of 
the gear of the previously selected pair the coil 75 of electromagnetic 
solenoid 71 is energized to produce disengagement movement of actuating 
tip 5. The electromagnetic force induced by the coil 75 of electromagnetic 
solenoid 71 overcomes the force of spring 74 and the force of the 
mechanical lock 76 and causes engagement pins 4 to be retracted into 
locating tube 1, permitting the tube to be displaced to effect the 
selection movement of the new gear pair Electromagnetic solenoid 71 does 
not rotate with hollow shaft 2 but rather is displaced axially therewith 
during the selection movement of the gear pair Electromagnetic solenoid 71 
is attached to hollow shaft 2 through two roller bearings 78 which permit 
relative rotation therebetween, but do not permit relative axial movement 
therebetween, Electromagnetic solenoid 71 has an extension 79 which is 
connected to an anchoring tube 80. Extension 79 enters and exits from 
anchoring tube 80 during the selection movement of the gear pair and 
anchoring tube 80 is secured to the housing 10 of the transmission. A key 
81 attaches the anchoring tube 80 to extension 79 of the electromagnetic 
solenoid 71 whereby electromagnetic solenoid 71 cannot rotate relative to 
housing 10 and is capable only of relative axial movement with respect 
thereto. The extension 79 also contains cables 82 which will transmit the 
electrical current to the coil 75 of electromagnetic solenoid 71. 
Governing unit 18 acts on a relay logic 83 which can energize or 
de-energize coil 75 of electromagnetic solenoid 71 by receiving energy 
from an electric voltage source 84. When coil 75 is energized, actuating 
pin 70 overcomes the force of spring 74 and of mechanical lock 76 and 
disengagement is effected. Without energy from source 84 coil 75 does not 
act on the actuating pin 70 and therefore the spring 74 produces 
engagement of pins 4. In order to ensure that locating tube 1 accurately 
effects the location movement for speed selection, the mechanism is 
provided with a sensor for measuring such position so that governing unit 
18 monitors and produces the correct position of speed selection. To 
ensure that engagement pins 4 attain the correct engagement and 
disengagement positions, a sensor measures the position of the engaged and 
disengaged pins. 
The present invention also concerns a synchronization system of the rotary 
parts driven by motor 16 in response to the electro-electronic actuator 
16A according to FIGS. 1 and 6. Synchronization will depend on whether the 
machine has been assembled with a constant speed drive motor 101 or a 
variable speed drive motor 121. It will depend also on the assembly of 
hollow shaft 2, which contains the gear shift mechanism, as regards 
whether the hollow shaft 2 is mounted at the input side as shown in FIG. 9 
or at the output side as shown at 105 in FIG. 9A. If, the motor 101 is of 
constant speed, according to FIG. 9, the motor drives the machine through 
clutch 102 and transmission 103 according to the following physical and 
mathematical relationships: 
Rotation of the input shaft of the transmission: Ns 
Transmission Ratio of a first gear pair: Ri 
Transmission Ratio of a second gear pair: Rj 
Index related to the first gear pair: (i) 
Index related to the second gear pair: (j) 
From the transmission equation of mechanics, we have, for a determined 
first pair of gears (i): 
EQU Nm(i)=Ns(i)xR(i) 
For the second gear pair (j) we have: 
EQU Nm(j)=Ns(j)xR(j) 
Since the motor in this case has a constant speed of rotation, then it is 
clear that: 
EQU Nm(j)=Nm(i)=Nm 
Therefore, when shifting from the gear pair (i) to the gear pair (j), said 
output speeds of rotation are related by the following expression: 
EQU Ns(i)xR(i)=Ns(j)xR(j) 
Then, the end output rotation speed will be: 
EQU Ns(j)=Ns(i)xR(i)/R(j) 
Ns(j) differs from Ns(i) by the ratio of the transmission ratios R(i) and 
R(j). Therefore, synchronization motor 16 from the moment when the clutch 
is released and the gear pair (i) is disengaged for a speed change, the 
synchronization motor 16 will have to change rotation speed of the output 
shaft, to speed Ns(j), which was prevailing prior to releasing the clutch, 
which requires a speed change from Ns(i), multiplied by ratio R(i)/R(j), 
in a predetermined time. Therefore, the rotating masses are accelerated or 
decelerated as a function of ratio R(i)R(j). At the moment that rotation 
R(j) has been attained, speed shift takes place, that is, there is an 
engagement of the gear pair (i). For perfect accuracy in the operation, 
the input and output speeds of rotation are constantly monitored by 
rotation sensors 93 and 94. Independently of where hollow shaft 2 is 
mounted or the output rotation side 105 (FIG. 9A), the synchronism system 
should be mounted at the output rotation side 105, since it is at this 
side that the rotating masses have to be accelerated or decelerated. 
If in this case, the machine motor or vehicle engine has a variable speed 
of rotation 121 as in FIG. 10, driving the machine or vehicle via clutch 
122 and transmission 123, then we have the following equations with the 
variables, previously described, for a determined pair (i): 
EQU Nm(i)=Ns(i)xR(i) 
For the other pair (j), we have: 
EQU Nm(j)=Ns(j)xR(j) 
Since the motor has a variable speed of rotation, and assuming that in the 
period of time of speed shift, the rotation speed remains unchanged, then: 
EQU Ns(i)=Ns(j)=NS 
Therefore, when shifting from the meshed pair (i) to meshed pair (j), said 
input speeds of rotation are related by the following expression: 
EQU Nm(i)/R(i)=Nm(j)/R(j) 
Then, the end input rotation should be: 
EQU Nm(j)=Nm(i)x(R(j)/R(i)) 
Nm(j) differs from Nm(i) by the inverse ratio of the transmission ratios 
R(i) and R(j). Therefore, the motor 16, starting from the moment in which 
the clutch is released and the gear pair (i) is disengaged for a speed 
shift, will have to cause the rotation speed of the input shaft, Nm(j), to 
be equal to the speed of rotation that was prevailing prior to releasing 
the clutch, namely, Nm(i), multiplied by the inverse ratio R(i)/R(j) in a 
predetermined fraction of time. Thereby, the rotating masses are 
decelerated or accelerated as a function of the inverse ratio R(i)/R(j). 
At the instant that rotation speed Nm(j) has been attained, the gear shift 
takes place, that is, the gear pair (j) is engaged. For perfect accuracy 
in the operation, the input and output speeds of rotation are constantly 
monitored by rotation sensors 93 and 94. Independently of where hollow 
shaft 2 is mounted, or of the rotation output side 125, as in FIG. 10A, or 
from the rotation input side, as in FIG. 10, the synchronization system 
must be mounted at the input side, since it is at this side that the shaft 
has to be accelerated or decelerated. The synchronization mechanism 
applied to the four disclosed embodiments is composed of direct or 
alternating current motor 16, driven by electro-electronic servo-actuator 
16A which, in turn, is controlled by governing unit 18. The direct or 
alternating current motor 16 has at one shaft end thereof, toothed or 
synchronizing pulley 91 which, in turn, transmits rotation to the toothed 
or synchronizing pulley 90 which is engaged with the shaft to which 
acceleration or deceleration will be imparted so that synchronized 
rotations are achieved. It is only during such synchronization event that 
the direct or alternating current motor 16 will be energized and at all 
other times it will be off and idle.