Abstract:
An operating device for an automated gear box having a shift gate with a selector slot, three or more shift slots intersecting the selector slot, and an actuator for actuating a gear or shifting shaft in shifting motions. The shifting shaft has a pin or shaft extending through the shift gate. A blocking device with one or more blocking elements moveable generally along the selector slot allows movement of the pin to an adjacent shift slot and shifting within the shift slot by the actuator while blocking further movement of the pin along the selector slot upon engaging a blocking element.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to automated gear boxes, and more particularly, to automated gear boxes operated by means of actuators. 
     2. Description of Related Art 
     Automated gearboxes in which a conventional manual gearbox is operated by means of actuators and connected to the engine of a motor vehicle by way of an automatic clutch are becoming increasingly important. They are less expensive than automatic gearboxes which are equipped with hydrokinetic torque converters and operate with planet gears, and the automated gearboxes operate with a higher degree of efficiency. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an operating device for an automated gearbox which renders it possible to achieve a high degree of operating reliability and can operate with simple actuators. 
     This object is accomplished with the features of the claim  1  or  2 . With the actuating device according to the invention, a blocking of the mobility of the gear shaft is achieved such that, in spite of the presence of at least three shift slots, it is possible to use stepless selector actuator the drive of which can be reversed in two opposing directions and the movement amplitude of which is defined not by a complex stepped control but rather by blocking the further mobility of the gear shaft by means of the blocking device or the end of the selector slot. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in greater detail with reference to the accompanying schematic drawings. 
     There are shown in: 
     FIG. 1 a shift gate for a gearbox having three shift slots, 
     FIG. 2 a plan view of the elements of a blocking device provided in the operating device for a gearbox with three shift slots, 
     FIG. 3 a side elevational view of the blocking device in FIG. 1 with further elements of the operating device, 
     FIG. 4 the shift gate of a gearbox with four shift slots, 
     FIG. 5 a plan view of a blocking device contained in the operating device for the gearbox with four slots, and 
     FIG. 6 a side elevational view of the device which is shown in FIG.  5 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, a shift gate of a gearbox has three shift slots with gears  1 ,  2 ;  3 ,  4  and  5 , R which are communicatively connected with each other by way of a selector slot W. In a conventional manual gearbox, such a shift gate determines the mobility of the selector lever; in an automated gearbox, the shift slot determines the mobility of a stop pin rigidly attached to a gear shaft. 
     FIG. 2 shows the shift gate recessed into a base plate  2 . Above the base plate  2  and between two stop pegs  4  and  6 , there is provided a guide pin  8  on which a blocking element  14  is movably guided between two springs  10  and  12 . The blocking element  14  has a lug  16  (see FIG. 3) which ends directly above the base plate  2 , which has a width approximating that of the selector slot W, and which can move along the selector slot. 
     FIG. 3 further shows that, below the base plate  2 , on a housing, a shifting shaft  18  is guided for rotary and axial movement relative thereto. Rigidly attached to the shifting shaft  18  is a stop pin  20  which extends into the shift gate and determines the extent of mobility of the shifting shaft  18 . To drive the shifting shaft  18 , which cooperates in a known manner with a gearbox (not shown), there are provided a selector actuator  22  as well as a shift actuator  24 . 
     The selector actuator  22  comprises a cylinder  24  for a reciprocable piston  28  which is attached to one end portion of the shifting shaft  18 . The piston  28  is biased in a direction to the left, as viewed in FIG. 3, by a coil spring  30 . By way of a valve  34 , which is operated by a control unit, and a conduit  32 , the right-hand chamber of the cylinder  26  can be subjected to subatmospheric pressure in order to overcome the bias of he spring  30  and to move the piston  28  in a direction to the right, together with the shifting shaft  18 . The valve  34  can connect the conduit  32  with the suction intake of a vacuum pump  31 . 
     To turn or index the shifting shaft  18  relative to the cylinder  26 , the selector actuator  24  comprises a pin  38  which is movable at right angles to the plane of FIG. 3 between the tines of a fork  40  which is attached to the shaft  18 . In order to move the pin  38  toward or away from the observer of FIG. 3, there is provided a double-acting cylinder  42  (or an equivalent motor). When the piston of the cylinder  42  is in a position of rest, the shifting shaft  18  is indexed to an angular position in which the stop pin  20  is located in the selector slot W. The piston in the double-acting cylinder  42  has two end positions in each of which the selector pin  20  is located at a different end of the then aligned shift slot. 
     The shifting shaft  18  is further provided with a collar  46  which can be arrested in a predetermined axial position of the shaft  18 , and in a manner to be explained hereinafter, by means of a bolt  48  which can be activated by an electromagnet  50 . 
     The mode of operation of the aforedescribed operating device is as folows: 
     Let it be assumed that the parts of the operating device are held in the positions which are shown in FIG. 3, i.e., the blocking element  14  is maintained in its position of rest at which time the lug  16  registers with the selector slot W exactly between the first shift slot (gears  1  and  2 ) and the second shift slot (gears  3  and  4 ). The right-hand chamber of the cylinder  26  is not maintained below atmospheric pressure so that the spring  30  is free to bias the piston  28  in a direction to the left whereby the stop pin  20  registers with the first shift slot because it is located in the left-hand end portion of the selector slot W and is ready to shift the transmission into the first gear  1  or into the second gear  2 . If the second shift slot is selected, the right-hand chamber of the cylinder  26  is connected with the suction generating device  31  by way of the valve  34  and the lug  16  moves along the selector slot W until the stop pin  20  reaches a position of alignment with the shift slot for the gears  4  gears  3  and  4 . The lug  16  is then prevented from moving in a direction to the right beyond the position in which the stop pin  20  registers with the median shift slot because the element  14  abuts the stop peg  6 . 
     In order to actually shift into the gear  3  or  4 , the stop pin  20  releases the lug  16  so that the blocking element  14  returns to its position of rest. With the gear  3  or  4  ready to be engaged, bolt  48  is moved by the lifting electromagnet  50  in a direction toward the shifting shaft  18  and the valve  34  permits the pressure in the right-hand chamber of the cylinder  26  to rise. The spring  30  is free to push the piston  28  and the shaft  18  in a direction to the left but only until the left-hand end face of the collar  46  reaches and abuts the bolt  48 . Such operation ensures that the stop pin  20  remains in register with the median shift slot (gears  3  and  4 ). In order to change to the third shift slot (gears  5  and R), the right-hand chamber of the cylinder  26  is again connected with the suction generating device  31  so that the stop pin  20  can be moved along the selector slot W and into alignment with the third shift slot (gears  5  and R). The selection of R can be blocked or permitted by one or more additional blocking devices, not shown. 
     If the second shift slot (gears  3  and  4 ) is to be selected again, the pressure in the right-hand chamber of the cylinder  26  is permitted to rise so that the shaft  18  can be shifted by the resilient element  30  until the collar  46  again reaches and is arrested by the extended bolt  48 . 
     In order to shift from the second or median shift slot to the first shift slot (gears  1  and  2 ), the electromagnet  50  withdraws the bolt  48  which latter is not acted upon by radial forces because of the shift gate guide of the stop pin  20 . The stop pin  20  thereupon moves the control element  14  to the left in the selector slot W against the left-hand stop peg  4  and can be moved along the first shift slot. 
     Thus, the just described operating device permits an extraordinarily safe gear engagement with actuators which are simple to construct and control with low control complexity. 
     FIGS. 4 to  6  illustrate a further design form of an operating device, namely for a gearbox with four shift slots (R;  1 ,  2 ;  3 ,  4 ;  5 ,  6 ) and one selector slot W (see FIG.  4 ). 
     For components of identical design as those shown in FIGS. 1 to  3  or performing the same function, the same reference characters are used so that only the differences are explained. 
     Two blocking elements  60  and  62  are guided on a guide pin  8  between springs  10  and  12  and, when in a position of rest, their lugs  64  and  66  are aligned with the selector slot W (identified in FIG. 4) between the first shift slot (R) and the second shift slot ( 1 ,  2 ) or between the second shift slot and the third shift slot ( 3 ,  4 ). Lugs  64  and  66  of the blocking elements  60  and  62 , forced into mutual contact by the springs  10  and  12 , hold between them in the rest position the stop pin  20  of the shifting shaft  18 . 
     The blocking device which, in the embodiment of FIGS.  1  to  3 , includes the electromagnet  50 , the bolt  48  and the collar  46 , again includes an electromagnet  50  and a bolt  48 ; however, the bolt  48  of FIG. 5 cooperates with a blocking socket  68  provided on a rod  70  which is movably mounted in a housing and is attached to the blocking element  60 . 
     The mode of operation of the device shown in FIGS. 4 to  6  (the actuators for the shifting shaft  18  are not shown) is as follows: 
     In the illustrated position, the bolt  48  engages the blocking socket  68  and thus fixes the left-hand blocking element  60  between the first and second shift slots. A shifting of the gearbox into the first shift slot, i.e., selection of reverse gear R, is excluded. 
     If the reverse gear is to be selected, the bolt  48  is withdrawn from the blocking socket  68  by deenergization of the electromagnet  50  which preferably takes place while the first or second gear is still engaged so that the bolt  48  is not acted upon by lateral forces due to the fact that the stop pin is confined in the first shift slot. 
     If the shift actuator (not shown in FIGS. 4 to  6 ) is no longer activated, the stop pin  20  moves into the selector slot W and carries the blocking element  60  in a direction to the left, with selector shaft  18  impacted to the left by the selector actuator, not shown, so that the blocking element  60  comes to rest at the stop peg  4  and selection of reverse gear is made possible. When the reverse gear is engaged, the blocking element  60  is moved back into the rest position by the spring  10 . 
     For changing from the first shift slot to the second shift slot, the two blocking elements  60  and  62  are moved to the right from the stop pin  20  which now lies at the left at lug  64 , so that the blocking element  62  comes to rest at the right-hand stop peg  6  and the mobility of the stop pin  20  to the right beyond the second selector slot is blocked. During shifting into the first or second gear, the blocking elements are released and pushed back into the rest position by the right-hand spring  12 . Locking bolt  48  again blocks the blocking socket  68  so that shifting between gears  1  and  2  takes place along the blocked blocking element  60 . 
     A further gear changing into the third shift slot now takes place while the fourth shift slot is blocked by the blocking element  62  which is pushed against the right stop peg  6  during the selection process. If one of the gears  3  and  4  is selected, the blocking element is pushed by via spring  12  and blocks the second shift slot. Shifting can now take place between the gears  3  and  4 , and this shift takes place along the blocking element  62  blocked to the left against further movement by the blocking socket  68 . To change to the fourth slot, the shifting shaft  18  is biased to the right where the fourth shift slot can be selected and engaged with the stop pin  20  supported on the right-hand edge. 
     To change from the fourth shift slot, the shifting shaft  18  is urged to the left as seen in the Figures. To reselect the first shift slot, the blocking socket  68  is released by the bolt  48  so that, on changing to the first shift slot, the two blocking elements  60  and  62  can be moved to the left and after selecting the gear  1  or  2 , the starting position shown can be reassumed whereupon the bolt  48  is again moved into the blocking socket  68  so that a shifting between the gears  1  and  2  can take place along the blocking element  60  with the shifting shaft  18  urged to the left. 
     It will be seen that the operating device of FIGS. 4 to  6  can function with a stepless selector actuator which biases the shifting shaft either in one or the other direction. 
     Naturally, the operating device can be modified in many ways. The blocking device can function hydraulically. The selector actuator can work with positive pressure or it can use two springs of which either the one or the other is activated. By utilizing several blocking elements and a blocking device interacting with the shifting shaft and/or the blocking elements, shift gates with more than four shift slots can be utilized, etc. 
     An operating device for an automated gearbox comprises a shift gate with one selection slot and at least three shift slots extending at least substantially at right angles to the selection slot, a shifting gear shaft which is rigidly connected with a stop pin extending through the switch gate, a selection actuator for moving the shifting shaft in the selection direction, a shift actuator for moving the shifting shaft in the shift direction, and a blocking device for blocking the mobility of the stop pin along the selection slot such that a change from one shift slot to an adjacent shift slot is possible and within each shift slot shifting is possible with the shifting shaft biased in one direction by the selection actuator. 
     The patent claims submitted with the application are proposed formulations without prejudice for the achievement of additional patent protection. The applicant reserves the right to claim further features heretofore disclosed only in the specification and/or in the drawings. 
     The back-references used in the dependent claims refer to further developments of the subject matter of the parent claim by the features of the respective dependent claim; they are not to be regarded as a waiver of the achievement of objective independent protection for the features of the respective dependent claims. 
     On the contrary, the features recited in the dependent claims constitute independent inventions which have a status independent of the features of the preceding dependent claims. 
     Moreover, the invention is not limited to the described embodiments. On the contrary, within the framework of the invention, numerous modifications and deviations are possible, in particular such variants, elements and combinations and/or materials which are novel for example by combination of or deviation from features or elements or process steps described individually in connection with those described in the general description and design forms and claims and contained in the drawings, and lead by combinable features to a new object or new process steps or process step sequences, even where these concern production, testing and modes of operation.