| 摘要 |
<p>The central locking installation for motor vehicles comprises a plurality of electric bolt drives (1) and a time control system (17, 19) trippable by at least one manually actuatable control switch (21). In a first switch position of the control switch (21) the system switches on the bolt drives (1) for a first pre-determined time period in the locking direction and in a second switch position of the control switch (21) switches them on for a second pre-determined time period in the unlocking direction. For automatic overload prevention a capacitor (27) is provided which is charged through a charging current circuit (29, 31, 33) enabled by the time control system (17, 19) during the pre-determined first and/or second time period. A threshold stage (37, 41, 43, 45) which blocks the time control system (17, 19) on reaching of a pre-determined value of the capacitor voltage for the switching on of the bolt drives (1) in the locking and/or unlocking direction is connected to the capacitor. Furthermore a discharge current circuit (35) enabled at least when the bolt drives (1) are switched off is connected to the capacitor. The threshold stage (37, 41, 43, 45) preferably has a hysteresis property and enables the bolt drives (1) again at a value of the capacitor voltage which is less than that value of the capacitor voltage at which the bolt drives (1) are blocked.</p> |
