The problem is solved, according to the invention, by the characteristics
claimed in Claim 1. Further advantageous developments are described in the subsidiary claims.
2 Accordingly, the invention provides device for actuating the throttle valve in the mixture-former of an internal combustion engine, with an electric motor which, acting through a speed-reduction gear and a throttle-actuator lever, actuates the throttle valve, characterised in that the device also has a conventional arrangement comprising an accelerator pedal capable of actuating the throttle valve through a throttle cable and a throttle cable anchor plate; and in that the device has a coupling and decoupling lever which, when the device is operating normally, is held, against the influence of a retum-spring, by a locking device in position of rotation where it is out of the path of movement of the throttle-cable anchor plate; the locking device being capable of releasing the coupling and decoupling lever in response to a signal so that the coupling and decoupling lever rotates into the path of movement of the throttle-cable anchor plate; the coupling and decoupling lever interrupting, in this movement, the drive-connection between the speedreduction gear and the throttle-actuator lever and connecting, instead, the throttle-actuator lever to the coupling and decoupling lever; so that the return-spring now acts on the throttle-actuator lever, rotating this back into a position determined by the position adopted by the throttlecable anchor plate in response to the movements of the accelerator pedaL A particular advantage of the invention is that by providing an emergency mechanical connection, for example an actuating cable, between the accelerator pedal and the throttle valve, even when a fault occurs in the electronic control system the vehicle can still be driven in the normal manner, the driver actuating the throttle valve directly, no accident hazard occuring and the driver still being able to reach a repair workshop by normal operation of the vehicle.
One example of the invention shown in the drawing will now be described.
Figure 1 shows the device in normal operation, the engine being assumed to be idling.
Fig-tue 2 shows the parts in the positions they have adopted after a fault has occured, the engine still being assumed to be idling.
Figffe 3 is a cross section corresponding to Figure 2.
11 0 3 In Figure 1 the device 1, for actuating the throttle valve, which is shown at 26 in Figure 3, is operating normally, the engine (not shown) being assumed to be idling. Figure 3 shows a closure plate 4 on which is mounted an electric motor 5 which, in normal operation, acting through a toothed pinion 3, rotates the throttle-valve shaft 2. In Figures 1 and 2 the closure plate 4 and the electric motor 5 have been removed to reveal the interior of the device. Nevertheless, Figures 1 and 2 both show the toothed pinion 3 and the throttle-valve shaft 2.
The toothed pinion 3 of the electric motor 5 meshes with teeth on the rim of a segmental plate 6 mounted rotatable on the hub of a throttleactuator lever 7 fixed to the throttle-valve shaft 2. When the device is in normal operation the segmental plate 6 is drive-connected to the throttle-actuator lever 7 by a coupling member 8 (whose method of functioning will be described further below) so that rotation of the segmental plate 6 rotates the throttle-valve shaft 2 and the throttle valve 26.
Mounted to rotate, coaxially with the throttle-valve shaft 2, on an inwards-projecting hub 9 (Figure 3) of the housing 24 is a throttle-cable anchor plate 10 for a conventional throttle-actuating cable 14. And, also mounted to rotate on the housing hub 9, there is a coupling-anddecoupling lever 11, which springs into action when a fault occurs.
In Figure 1 the coupling and decoupling lever 11 is shown held by a retractable pin 12 in a downward position out of the path of movement of the throttle cable anchor plate 10. When a fault occurs the pin 12 is retracted by the emergency pin-retractor shown at 13, releasing the coupling-and-decoupling lever 11. The throttle-actuating cable is connected, as is conventional, to the accelerator pedal of the vehicle.
In Figure 2 the parts of the device are shown in the positions they adopt after a fault has occured. The emergency pin-retractor 13 has retracted the pin 12, releasing the coupling-and-decoupling lever 11 so that it rotates anti-clockwise, as represented in Figures 1 and 2, influenced by a torsion spring 15, shown at the right in Figure 3, into the path of movement of the throttle-cable anchor plate 10. At the end of this rotation a pin 16 projecting sideways, towards the left in Figure 3, from a spring-loaded catch 17 on the coupling and decoupling lever 11 strikes the coupling 4 member 8, rotating it anti-clockwise into the position shown in Figure 2. The catch 17, which pivots on a pivot pin 18, is spring-loaded by a leaf- spring 23 (Figure 3). In its anti-clockwise rotation the coupling member 8 rotates a coupling segment 19 so that its edge lifts out of a notch 20 in the upper rim of the segmental plate 6, disengaging this from the throttle-actuator lever 7 so that the segmental plate 6 is no longer drive-connected to the throttle-valve shaft 2. Furthermore, at the end of the anti-clockwise rotation of the coupling and decoupling lever 11 a notch 21 (Figure 1) in the spring-loaded catch 17 engages, under the influence of the leaf-spring 23, over an upper projection 22 of the throttle-actuator lever 7, establishing drive-connection between the coupling and decoupling lever 11 and the throttle valve shaft 2.
The functions of several other parts shown and numbered in Figures 1 and 2 will now be described with the help of Figure 3.
In Figure 3, which shows, as does Figure 2, the parts of the device in the positions they adopt after a fault has occured, there can be seen the housing 24 of the device and, at the right, the intake passage 25 of the engine, with its throttle valve 26. A chamber 27 in the housing 24 contains the parts of the device. At the left in Figure 3 there can be seen the closure plate 4, through which penetrates the shaft 28 of the toothed pinion 3 of the electric motor 5 which, as already mentioned, drives the segmental plate, 6 in rotation, when the device is operating normally.
When the device is functioning normally the segmental plate 6, rotating clockwise against the influence of a torsion spring 29 (not shown in Figures 1 and 2) anchored to the housing 4 and, acting through the coupling member 8 and the throttle-actuator lever 7, rotates the throttlevalve shaft 2 and the throttle valve 26 clockwise towards its more open position.
Figure 3 also shows, towards the right, the inwards-projecting housing hub 9 on which rotates the throttle-cable anchor plate 10. This is influenced to rotate anti-clockwise (as represented in Figures 1 and 2) by a torsion return spring 30 (Figure 3) which serves only to keep the throttle cable 14 taut when pressure on the accelerator pedal is relaxed.
^cl Mounted rotatable on the same housing hub 9 is the coupling and decoupling lever 11 which, when released by retraction of the pin 12, rotates anti-clockwise under the influence of the torsion spring 15, whose inner end is attached to an arm 3 1 projecting (towards the right in Figure 3) from the coupling and decoupling lever 11. When the coupling and decoupling lever 11 has rotated anti-clockwise, after retraction of the pin 12, the arm 31 rests against a surface of the throttle-cable anchor plate 10 and, consequently, when a pull on the cable 14 rotates the coupling and decoupling lever 11 clockwise this also rotates the coupling and decoupling lever 11 clockwise, against the influence of the torsion spring 15.
As already described in connection with Figure 2, in the anti-clockwise rotation of the coupling and decoupling lever 11, after the pin 12 has been retracted, the pin 16 projecting sideways from the catch 17 (which pivots on the pin 18 of the coupling and decoupling lever 11) strikes the coupling member 8, tilting it anti-clockwise against the influence of a leaf-spring 32 (Figure 2) so that the edge of the coupling segment 19 lifts out of the notch 20 in the upper rim of the segmental plate 6. This interrupts the drive connection from the segmental plate6, through the throttle-actuator lever 7, to the throttle-valve shaft 2, i.e. the electric motor 5 is no longer drive connected to the throttle-valve shaft 2. A further consequence of the anti-clockwise rotation of the coupling and decoupling lever 11, after the pin 12 has been retracted, is that at the end of this rotation the catch 17, pivoting resiliently on its pivot pin 18, has snapped home, influenced by its leaf-spring 23 (Figure 3), over the projection 22 (Figure 2) projecting upwards from the throttleactuator lever 7. This drive-connects the coupling and decoupling lever 11, and with it the throttle-cable anchor plate 10, through the throttleactuator lever 7 to the throttle-valve shaft 2.
The emergency pin-retractor 13 can be an electromagnetic positioner or some other kind of actuator, such as a pneumatic or hydraulic actuator.
Method of func In normal operation the parts of the device are positioned as represented in Figure 1. Actuation of the accelerator pedal by the driver of the vehicle influences the control-computer to send command signals to the electric motor 5, which responds 6 by driving the segmental plate 6, with the help of the toothed pinion 3, the throttle-actuator lever 7 and the throttle-valve shaft 2, in positioning the throttle valve 26 accordingly.
On the other hand, when a mechanical, electrical or electronic fault occurs in the throttle-control system, this is detected by a recognition circuit, or by the fact that the electric motor is taking current differently. When this happens a command signal is delivered to the emergency pin-retractor 13, which responds by retracting the pin 12, releasing the coupling and decoupling lever 11 to rotate anti-clockwise under the influence of its torsion spring 15.
Supposing now that at the time when the coupling and decoupling lever 11 is rotating anti-clockwise, the throttle valve 26 has been rotated into a more open position than what corresponds to the position of the driver's accelerator pedal, the pin 16 of the coupling and decoupling lever 11 strikes the coupling member 8, tilting it over anti-clockwise and lifting the edge of the coupling segment 19 out of the notch 20 in the upper rim of the segmental plate 6, interrupting drive connection between the segmental plate 6, interrupting drive-connection between the segmental plate 6 and the throttle-valve shaft 2 so that the toothed pinion 3 is no longer able to rotate the throttle valve 26. Furthermore, in the anticlockwise rotation of the coupling and decoupling lever 11 the catch 17 engages with its notch 21 over the projection 22 of the throttle-actuator lever 7, drive-connecting the coupling and decoupling lever 11 to the throttle-actuator lever 7, whereupon the torsion spring 15, rotating the coupling and decoupling lever 11 and, with it, the throttle-actuator lever 7 anti-clockwise, rotates the throttle 26 towards its closed position until, ultimately, the arm 31 of the coupling and decoupling lever 11 comes to rest in contact with the throttle-cable anchor plate 10.
It should be observed that when a fault occurs in the throttle-control system the device of the invention alerts the driver by increasing the thrust he has to apply to the accelerator pedal in opening the throttle, inducing him to seek the help of a repair workshop. The personnel of the repair workshop, after repairing the control system, must first rotate the coupling and decoupling lever 11 clockwise out of the path of the throttle-cable anchor plate 10 and then advance the pin 12 into its locking position, before the electric motor 5 can once more control the position of the throttle valve 26.
7 CLAINIS 1. A device for actuating the throttle valve in the mixture-former of an internal combustion engine, with an electric motor which, acting through a speed-reduction gear and a throttle-actuator lever, actuates the throttle valve, characterised in that the device also has a conventional arrangement comprising an accelerator pedal capable of actuating the throttle valve (26) through a throttle cable (14) and a throttle cable anchor plate (10); and in that the device has a coupling and decoupling lever (11) which, when the device is operating normally, is held, against the influence of a retum-spring (15), by a locking device (12,13) in position of rotation where it is out of the path of movement of the throttle-cable anchor plate (10); the locking device (12,13) being capable of releasing the coupling and decoupling lever (11) in response to a signal so that the coupling and decoupling lever (11) rotates into the path of movement of the throttle-cable anchor plate (10); the coupling and decoupling lever (11) interrupting, in this movement, the drive-connection between the speed-reduction gear (3, 6) and the throttle- actuator lever (7) and connecting, instead, the throttle-actuator lever (7) to the coupling and decoupling lever (11); so that the return-spring (15) now acts on the throttle-actuator lever (7), rotating this back into a position determined by the position adopted by the throttle-cable anchor plate (10) in response to the movements of the accelerator pedal.