Patent Publication Number: US-6662608-B1

Title: Central locking drive

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to a central locking drive for the actuation of various locking functions of a door lock, especially in motor vehicles&#39; with two drive members, which are each displaceable between an inoperative position and an activated position. 
     In addition to the known locking functions of central locking and central unlocking, the other function mostly demanded of present-day central locking systems is that of central security, in which unlocking of the external door handle and/or opening of the door by operating the internal door handle is prevented. This is required for anti-theft protection, since a vehicle door in this position cannot be readily opened even after smashing in a vehicle window. In order to be able to actuate this third locking function, it must be possible for the central locking drive to run into a third position, which can be achieved, for example, by means of an additional second drive member, such as a motor or a lifting magnet, or by purposely assuming an intermediate position of the first drive member with the aid of a switch or potentiometer, for example, the two limit stops of the drive member and the intermediate position defined by the switch or the potentiometer defining the three operating positions in the case of an intermediate position. 
     Yet a further locking function, that is child safety, is necessary on the rear doors of a motor vehicle. This is basically intended to prevent opening of the door by means of the internal door handle, but in the central locking position to permit unlocking of the external door handle by operating the internal door handle, since otherwise with central locking and child safety activated the central security function would virtually be engaged. 
     The additional function has hitherto generally been achieved by mechanical intervention in the lock with the door open, whereas an additional drive member is required for integration into the central locking drive. Consequently either three drive members at correspondingly high cost or a solution with two drive members and an electrical switch for detecting an intermediate position are required in order to achieve all the above-mentioned locking functions electrical switches however, being just as highly expensive in terms of circuitry as the detection of intermediate positions by means of potentiometers and having a certain susceptibility to malfunction. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to create a central locking drive that relies on just two drive members and permits actuation of at least the desired locking functions central locking, central unlocking central security and child safety simply by displacement of the drive members between their limit positions. 
     According to the invention the object is achieved by a central locking drive of the type initially described, in which an operating element is provided which is moveable between a neutral position, which it assumes when the two drive members assume their inoperative position, and at least one operating position, the attainment of a particular operating position of the operating element being dependent upon the order in which the two drive members are activated. 
     In the solution according to the invention the additional locking function is defined by the order in which the two drive members are actuated, there being no need to arrest these in intermediate positions. In terms of control technology the encountering of limit stops is very simple, the differing sequence for the actuation of the two drive members also being very easily accomplished in terms of control technology. The elimination of a third drive member or an additional electrical switch provides for savings in the overall space required and in the weight of the central locking drive, savings also being achieved through being able to dispense with the corresponding electrical wiring. 
     Provision is preferably made so that a first drive member, in its activated position, deadlocks or interrupts the connection between an internal door handle and the door lock, and the second drive member, in its activated position, deadlocks or interrupts the connection between an external door handle and the door lock. An interruption or deadlocking of the connections by the drive members in their inoperative position is also feasible depending on the definition. The connection between the door handles and the door lock may be of mechanical or electrical design. 
     In a further preferred embodiment of the invention it is proposed that the operating element be moveable by operation of the first drive member and subsequently moving the second drive member into a first operating position, in which it is possible to unlock the external door handle by operating the internal door handle. 
     In a central locking drive of this type the aforementioned locking functions are configured so that the central unlocking function is engaged when the drive members are in the inoperative position, the child safety function with external door handle unlocked is engaged when the first drive member is activated and the second drive member is in the inoperative position, the central locking function with the facility for opening the door from inside is engaged when the second drive member is activated and the first drive member is in the inoperative position, the child safety and central locking function with the facility for unlocking the external door handle by operating the internal door handle is engaged when the first drive member is activated first and the second drive member is activated subsequently, and the central security function is engaged when the second drive member is activated first and the first drive member is activated subsequently. 
     It is also feasible that in one operating position the operating lever might interrupt or deadlock a facility for unlocking the external door handle by means of the internal door handle. Such a design is conceivable in combination with a facility, purposely established by the operating element in its first operating position, for unlocking the external door handle by means of the internal door handle or even in the case of a central locking drive, in which such a facility exists whenever the operating element is not in a certain operating position. 
     Interacting cam elements are preferably provided on the operating element and on each of the drive members respectively, which on activation of the first drive member cause the operating element to be shifted into a first intermediate position and on subsequent activation of the second drive member cause the operating element to be shifted further into the first operating position, and on initial activation of the second drive member cause the operating element to be shifted into a second intermediate position and on subsequent activation of the first drive member cause it to be shifted into a limit position or second operating position other than the first operating position. 
     Such a solution for operation of the first operating element by the drive members in which the cam elements provided on the operating element have, for example, lifting flanks inclined in relation to the direction of movement of the cam elements on the drive members permits simple mechanical driving of the operating element into the required operating position by engaging the limit positions of the drive members. 
     The operating element is preferably returned towards its neutral position by means of a return spring. Alternatively a mechanical drive into the neutral position by returning the drive members to their inoperative position is also feasible, for example. 
     The central locking drive according to the invention may in principle rely on widely differing types of drive members such as motors or electromagnets for example. Thus the drive members in a preferred embodiment of the invention have electric drive motors which are each traversable between two stops which represent the inoperative position or the activated position of the respective drive member. Electric drive motors are of very compact construction, have only a relatively low power input and are very quiet in operation, it being possible to detect the stop positions for switching off the drive motor by detecting the power input. The drive motors preferably drive spindles which engage with adjusting nuts on which the cam elements are arranged. In order to guide the operating lever accurately between its various positions it may be pivotally mounted, although a linear guide, for example, is also conceivable. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One embodiment of the invention will be examined in more detail below with reference to the figures of the drawings attached, in which: 
     FIG. 1 shows a diagrammatic oblique view of a central locking drive; 
     FIG. 2 shows an oblique view of the operating element of the central locking drive according to FIG. 1; and 
     FIGS. 3 to  7  show diagrams of the central locking drive according to FIG. 1 in various operating positions. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The central locking drive  10  represented in FIG. 1 has a first operating lever  12 , by means of which the connection between an internal door handle (not shown) and a door lock (likewise not shown) can be deadlocked or interrupted, and a second operating lever  14 , which acts correspondingly on the connection between an external door handle (not shown) and the door lock. The two operating levers  12 ,  14  are mounted so that they can pivot about a common axis of rotation  16 . 
     The first operating lever  12  is connected to a first adjusting nut  18 , which engages with the external thread of a first threaded spindle  20 , which can be driven by a first electric drive motor (not shown). 
     The second operating lever  14  is connected to a second adjusting nut  22 , which engages with the external thread of a second threaded spindle  24 , which can in turn be driven by a second electric motor (likewise not shown). 
     By means of the electric drive motors the two adjusting nuts  18 ,  22  are traversable between two stops which define the inoperative position or the activated position of the respective drive members. 
     In addition to the two adjusting nuts  18 ,  22  the central locking drive  10  has an operating element  26 , which is mounted so that it can pivot about a swivel axis  28 . In order to effect a return of the operating element  26  following displacement, a return spring is provided, which is designed as leaf spring and is fixed to the swivel axis  28 . 
     The central locking drive furthermore has a device (not shown), intended for generally unlocking the external door handle by operating the internal door handle, these functions being described in more detail below. 
     FIG. 2 shows an oblique view of the operating lever  26  from the side facing the adjusting nuts  18 ,  22 . Also visible in addition to the swivel axis  28  are a first control cam  32  with two inclined lifting flanks  34 ,  36 , which interacts with a first actuating cam  38  (see FIGS. 3-7) on the first adjusting nut  18 , and a second control cam  40 , which likewise has two inclined flanks  42 ,  44  and interacts with a second actuating cam  46  on the second adjusting nut  22 . A locking cam  48 , which will be explained in more detail later, is also provided on the operating element  26  in an approximately central position. 
     The interaction of the cam elements that is the interaction of the actuating cams  38 ,  46  with the control cams  32 ,  40 , is illustrated in FIGS. 3-7. For this purpose only the adjusting nuts  18 ,  22  and the operating element  26  are shown. With the adjusting nuts  18 ,  22  in the position represented in FIG. 3 the central locking is in the centrally unlocked position, in which the door lock can be operated both by the internal door handle and the external door handle. The operating element  26  is in its neutral position. 
     If the second adjusting nut  22 , which acts on the operating lever for the external door handle, is moved out of the position shown in FIG. 3 into its locking position, in which the connection of the external door handle to the door lock is interrupted or deadlocked, corresponding to the centrally locked position, the second actuating cam  46  will, during the operating movement, strike the upper inclined lifting flank  42  of the second control cam  40 , thereby swiveling the operating element  26  downwards in the illustration shown counter to an accumulating return force of the return spring  30 . Under the swiveling movement of the operating element  26  the upper inclined lifting flank  34  of the first control cam swivels into the moving path of the first actuating cam  38  on the first adjusting nut  18 , so that on subsequent actuation of the first adjusting nut the operating element  26  is swiveled further downwards until the locking cam  48  swivels into the moving path of the second adjusting nut  22 . Canceling of the locking position of the external door handle is thereby no longer possible, since the second operating lever  14  is deadlocked in its locked position, and on operation of the internal door handle the unlocking mechanism is similarly deadlocked. 
     Disengagement, that is an interruption of the unlocking mechanism between the internal door handle and the second operating lever  14  is also conceivable instead of deadlocking by means of the locking cam  48 . The position of the adjusting nuts  18 ,  22  and the operating element  26  shown in FIG. 5 therefore corresponds to the central security function position of the central locking, which as anti-theft protection prevents opening of a vehicle door even after the side windows have been smashed in. As soon as the two adjusting nuts  18 ,  22  are returned to their initial position, the operating element  26 , under the action of the return spring  30 , swivels back into its neutral inoperative position, and the original centrally unlocked state represented in FIG. 3 is resumed. 
     If, from this condition, the first adjusting nut  18  is first shifted from the inoperative position into its activated position by corresponding actuation of its drive motor, the first actuating cam  38  does not strike the upper inclined flank  34 , but the lower inclined flank  36  of the first control cam  32 . This causes the operating element  26  to swivel upwards in the representation shown, so that the upper inclined lifting flank  42  of the second control cam  40  is swiveled out of the moving path of the second actuating cam  46 . In the position of the central locking drive shown in FIG. 6 the connection of the internal door handle to the door lock is interrupted while the connection to the external door lock is maintained, that is to say the child safety function is activated in the central unlocking condition of the central locking. 
     If the second adjusting nut  22  is now shifted into its activated position, the second actuating cam  46  runs counter to the lower inclined lifting flank  44  of the second control cam  40  and displaces the operating element  26  upwards by a further distance, in which process the locking cam  48  does not obstruct the adjusting nuts  18 ,  22 . In this position it is not possible to open the door either by operating the external door handle or by operating the internal door handle, that is to say the child safety function is activated in the central locking position of the central locking. By operating the internal door handle, however, the second adjusting nut  22  can be returned to its inoperative position so that the locking of the external door handle can be canceled by operating the internal door handle. This is highly desirable for safety reasons in order to facilitate access to the rear bench seat of a vehicle in the event of accidents. 
     Instead of deadlocking the locking of the external door handle in the central security position it is also feasible to omit the locking cam  48  and to create the facility for unlocking the external door handle by operating the internal door handle only in the position of the central locking drive represented in FIG. 7 through a corresponding operating action of the operating element  26 . 
     Instead of a pivotably arranged operating element  26  it is also feasible to guide this linearly or to support it so that it can rotate about a longitudinal axis. Instead of designing the support elements for the actuating cams  38 ,  46  as adjusting nuts rotary driven elements may be provided, which act, for example, by way of a shaft and hollow shaft on radial pins in order to interrupt the connection between the external door handle or the internal door handle and the door lock. 
     The operating levers  12 ,  14  and the actuating cams  38 ,  46  may in principle also be operated by linear motors, electromagnets or other drive elements.