DEVICE FOR ADJUSTING THE OPERABILITY OF AN ACCELERATOR

Field of the Invention

The present invention relates to a device for adjusting the operability of an accelerator.

Background Art

Devices of the type described by way of introduction can be used to affect the behaviour of a driver of a motor-driven vehicle. More specifically, the device can affect the operability of the accelerator so that it will be more difficult or heavier to operate when the driver exhibits a non-desirable behaviour.

A device of this type is known from W0056566. The device affects an accelerator of a motor-driven vehicle so that the accelerator in a basic state is operable with difficulty. By activating the device, it will assist the operation of the accelerator in such a manner that it will be operable for the driver without difficulty. The device can be activated when the vehicle is driven at a speed below or equal to a currently prevailing permissible maximum speed, whereby the device will encourage a driving behaviour where the prevailing speed limit regulations are respected.

Although the prior art device functions in a satisfactory manner, its construction may in some cases cause problems since the construction is relatively complicated. This means that the prior art device can be both expensive and bulky.

Summary of the Invention

In view of that stated above, it is an object of the present invention to provide a device of the type described by way of introduction and having a relatively simply and compact construction.

To achieve this object, and also other objects that will be evident from the following description, a device having the features as defined in claim 1 is provided according to the present invention. Embodiments of the device are defined in claims 2-11 which are dependent on claim 1.

More specifically, according to the present invention a device is provided for adjusting the operability of an accelerator, such as a throttle pedal, said device comprising a cylinder, a piston which is arranged in the cylinder and movable relative to the cylinder from a first piston position to a second piston position against the action of a piston spring, an element which is arranged in the piston and connectable to the accelerator and which is movable relative to the piston from a first element position to a second element position against the action of an element spring, a piston moving means, which is arranged to move the piston between the first piston position and the second piston position. When the piston is in the first piston position, the accelerator is, in its state connected to the element, operable to increase the speed by moving the piston together with the element towards the second piston position. When the piston is between the first and the second piston position, the accelerator is operable by first moving the element to the second element position and then moving the piston together with the element towards the second piston position. When the piston is in the second piston position, the accelerator is operable by moving the element towards the second element position. The piston spring has a spring constant which is higher than a spring constant of the element spring.

Thus a device for adjusting the operability of an accelerator is provided, which device has a relatively simply and compact construction.

When the piston is in the first piston position, the accelerator is operable to increase the speed by moving

the piston together with the element towards the second piston position. This movement occurs against the action of the piston spring, which has a higher spring constant than the element spring. Thus, a comparatively greater effort is required to operate the accelerator in this situation.

When the piston is in the second piston position, the accelerator is operable to increase the speed by moving the element from the first element position to the second element position. This movement occurs against the action of the element spring, which has a lower spring constant than the piston spring. The effort to operate the accelerator is thus in this situation comparatively smaller . When the piston is in a position between the first and the second piston position, the accelerator is operable to increase the speed by first moving the element to the second element position and then moving the piston together with the element to the second piston position. The initial movement of the element occurs against the action of the element spring and thus is proportionately light. The subsequent movement of the piston together with the element occurs against the action of the piston spring and thus is proportionately heavy.

The inventive device consequently allows in a simple and reliable manner adjustment of the operability of the accelerator .

Moreover the device is largely accommodated in a cylinder, which means that it will be relatively compact.

In one embodiment of the invention, the piston moving means of the device is movable by a drive means, which may consist of an electric motor in the form of a direct-acting stepping motor. Thus the drive means affects the piston moving means so that the piston can be made to take a desired position in or between the first and the second piston position.

In a further embodiment, the drive means comprises a rotatable, threaded rod which engages a threaded hole in the piston moving means. Thus the drive means acts to rotate the rod, whereby the piston moving means can be made to take the desired position. As a result, the piston is moved by the piston moving means in a simple and reliable manner.

The piston spring can be a compression spring which is compressed in moving the piston from the first piston position towards the second piston position.

The element spring can be a compression spring which is compressed in moving the element from the first element position towards the second element position.

In another embodiment, the device comprises a con- necting means for connecting the accelerator to the element.

In yet another embodiment, the device comprises a control unit which is arranged to control the movement of the piston moving means as a function of predetermined parameters. These parameters may comprise prevailing speed limit regulations or use of safety belt. This makes it possible to adjust the operability of the accelerator to encourage a desired behaviour of the user.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings .

Brief Description of the Drawings

Fig. 1 is a schematic, part-sectional side view of an inventive device where a piston is in a first piston position and an element is in a second element position. Fig. 2 is a schematic, part-sectional side view of the device in Fig. 1 where the piston is in a second piston position and the element is in a first element position.

Fig. 3 is a schematic, part-sectional side view of the device in Fig. 1, where the piston is in the second

piston position and the element is in the second element position.

Fig. 4 is a schematic side view of an inventive device and an accelerator connected thereto, the accelerator being in an idle position.

Fig. 5 is a schematic side view of the device and the accelerator, the accelerator being in a position for maximum speed.

Description of Embodiments

Figs 1-3, to which reference is made, illustrate an embodiment of a device 1 according to the present invention.

The inventive device 1 comprises a cylinder 3 extending along a longitudinal axis 2 and a piston 4 arranged therein. The cylinder 3 has a suitable cross- section, such as a circular cross-section.

The piston 4 is movably arranged relative to the cylinder 3 between a first piston position indicated at A and a second piston position indicated at B. In the embodiment illustrated, the piston 4 is movable along the longitudinal axis 2 of the cylinder 3 between the first A and the second B piston position.

The piston 4 comprises a piston plate 5 which is slidable along the inner circumferential surface of the cylinder 3 between the first A and the second B piston position.

The piston plate 5 supports, on a surface facing away from a first end 6 of the cylinder 3, a hollow piston rod 8 which extends concentrically around the longitudinal axis 2 of the cylinder 3.

A piston moving means 9 is arranged in the cylinder 3 between the piston plate 5 and the first end 6 of the cylinder 3. A drive means 10 is arranged outside the cylinder 3 at the first end 6 thereof. In the example illustrated,

the drive means 10 comprises an electric motor 11 in the form of a direct-acting stepping motor.

The drive means 10 is arranged to move the piston 4 between the first A and the second B piston position by the piston moving means 9. For this purpose, the drive means 10 comprises also a rod 12 which is rotatable by the electric motor 11 and provided with an external thread. The threaded rod 12 extends into the cylinder 3 and engages a threaded hole 13 in the piston moving means 9. The treaded rod 12 further extends through the threaded hole 13 into the hollow piston rod 8.

By rotation of the threaded rod 12 by means of the electric motor 11 , the piston moving means 9 is consequently movable along the longitudinal axis 2 of the cylinder 3 and can thus be made to engage the piston plate 5 to move the piston 4 between its first A and second B piston position. The first piston position A is defined by a shoulder 14 formed in the inner circumferential surface of the cylinder 3 (see Fig. 1) and the second piston position B is defined by the position of the piston moving means 9 when moved to an outer end position on the treaded rod 12 (see Fig. 2) .

A piston spring 15 of compression spring type is arranged in the cylinder 3 concentrically and outside the piston rod 8. The piston spring 15 extends between the surface of the piston plate 5 facing away from the first end 6 of the cylinder 3 and a second end 7 of the cylinder 3. Thus the piston spring 15 will be compressed in moving the piston 4 from the first piston position A to the second piston position B.

An element 16 is arranged inside the hollow piston rod 8 and is movably arranged relative to the piston rod 8 between a first element position C and a second element position D. More specifically, the element 16 is slidable along the inner circumferential surface of the hollow piston rod 8.

The first element position C corresponds to a position at a first end 17 of the piston rod 8. To allow the element 16 to take this first element position C, the piston moving means 9 must be moved to the outer end position on the treaded rod 12 (see Fig. 2) so that said rod 12 no longer occupies the space inside the hollow piston rod 8.

The second element position D is defined by a shoulder 19 formed in the inner circumferential surface of the hollow piston rod 8 adjacent to a second end 18 thereof.

An element spring 20 of compression spring type is arranged inside the hollow piston rod 8 between the element 16 and the second end 18 of the piston rod 8. The element spring 20 will thus be compressed in moving the element 16 from the first element position C to the second element position D.

An accelerator, schematically illustrated at 21, is connectable to the element 16 via a connecting means 22 which in the embodiment shown is a wire.

The element spring 20 has a spring constant which is lower than a spring constant of the piston spring 15. The force required to compress the piston spring 15 is thus greater than the force required to compress the element spring 20.

Fig. 1 illustrates the piston 4 in its first element position A and the element 16 in its second element position D. The accelerator 21 is in a non-actuated position, corresponding to the idle position. If a user in this situation should want to increase the speed, he must affect the accelerator 21 by such a force that the piston 4 is moved together with the element 16 from the first piston position A towards the second piston position B, that is the user must overcome the counteracting force of the piston spring 15.

Fig. 2 illustrates the piston moving means 9 in such a position that the piston 4 is in the second piston

position B and the element 16 is in the first element position C. The accelerator 21 is again shown in a non- actuated position.

If a user in this situation should want to increase the speed, he must affect the accelerator 21 by such a force that the element 16 is moved from the first element position C towards the second element position D, that is the user must overcome the counteracting force of the element spring 20. Fig. 3 shows the accelerator 21 in a position for maximum speed, which means that the element 16 has been moved to the second element position D.

As described above, the counteracting force of the piston spring 15 is greater than the counteracting force of the element spring 20. Consequently, less effort is required to operate the accelerator 21 for increasing the speed when the inventive device 1 is in the state shown in Fig. 2 than in the case when the device 1 is in the state shown in Fig. 1.

If the piston moving means 9 has been actuated by the drive means 10 in such a manner that the piston 4 is in a position between the first A and the second B piston position, the user can operate the accelerator 21 to increase the speed by first moving the element 16 to the second element position D and then moving the piston 4 together with the element 16 towards the second piston position B. Initially the operation of the accelerator 21 will thus be proportionately light and, subsequently, heavy.

Figs 4 and 5, to which reference is now made, illus- trate the inventive device 1 in a state connected to an accelerator 21 in the form of a throttle pedal. More specifically, a connecting means 22 in the form of a wire extends from the element 16 of the device 1, through the second end 18 of the piston rod 8 and through the second end 7 of the cylinder 3 to the accelerator 21. In Fig. 4, the piston 4 is in the first piston position A and the accelerator 21 is in a position that corresponds to

idling. In Fig. 5, the piston 4 has been moved to the second piston position B, while at the same time the element 16 has been moved to the second element position D by operating the accelerator 21 for maximum speed. The inventive device 1 can further comprise a control unit (not shown) , which is arranged to control the movement of the piston moving means 9 performed by the driving means 10 as a function of predetermined parameters . These parameters can be such that the inventive device acts to encourage a desirable behaviour of a user, that is a driver of a motor vehicle equipped with an inventive device.

For instance, said parameters may concern the speed limit regulations prevailing for a given geographic area. Thus, the control unit can be supplied with information about the maximum permissible speeds prevailing in the current road system while, for instance, a GPS based system checks the position of the vehicle in the road system. The control unit detects the speed of the vehicle and compares it with the maximum permissible speed for the current road section. If the speed is below or equal to the maximum permissible speed, the control unit controls the drive means to make the piston moving means take a position, in which the accelerator is operable without difficulty.

The inventive device possesses the property of supplying information about the current speed limit to the user via the accelerator. The user will in fact when operating the accelerator experience an end position, in which the accelerator will be heavy to operate. This end position corresponds to the case when the element has been moved to the second element position and a further increase of the speed can only be achieved by moving the piston towards the second piston position.

Should the vehicle enter a road section with a lower permissible speed, the control unit will control the

piston moving means to be moved towards the first end of the cylinder. As a result, the piston spring will press the piston towards the first piston position, which in turn moves the element towards the second element position. If the element has been moved to the second element position, a further movement of the piston towards the first piston position will result in the user experiencing how the throttle pedal is pressed upwards. If the user wishes to continue driving at the current, non-permissible speed, a greater effort is thus required. If the user allows the foot to follow the throttle pedal, a new end position will appear, corresponding to the new speed limit.

The inventive device thus acts to encourage a cer- tain behaviour, in the example described above respecting the prevailing speed limit regulations. However, the device is not compelling, that is it is possible for the user to act contrary to the desirable behaviour, which can be important from a safety point of view. In over- hauling, it may for example in some cases be justified for a vehicle driver to exceed the permissible speed limit .

The above-mentioned parameters for the control means controlling the drive means may also concern, for instance, use of safety belt or activation of dipped headlights .

It will be appreciated that the present invention is not limited to the shown embodiment.

For example, it is conceivable to design the drive means in some other way. It is thus possible to design the drive means as a hydraulically or pneumatically acting means for moving the piston moving means.

It is also possible to design the piston spring and/or the element spring in some other way. For example, by suitable modification of the device, they can be in the form of tension springs.

Several modifications and variations are thus conceivable, and therefore the scope of the invention is exclusively defined by the appended claims .