GB1583477A

GB1583477A - Control devices

Info

Publication number: GB1583477A
Application number: GB3564377A
Authority: GB
Original assignee: Automobiles Citroen SA
Current assignee: Automobiles Citroen SA
Priority date: 1976-09-16
Filing date: 1977-08-25
Publication date: 1981-01-28
Also published as: FR2365161A1; IT1089882B; DE2741742A1; FR2365161B1; ES462201A1

Description

(54) IMPROVEMENTS IN OR RELATING TO CONTROL DEVICES (71) We, SOCIETE ANONYME AUTO MOBILES CITROEN, a French Body Corporate, of 117-167 Quai André Citröen, 75747 Paris Cedex 15, France, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to control devices.

According to the present invention, there is provided a control device operatively connected to a mechanism for controlling said mechanism against the action of a first return member which tends to return the mechanism to a first position, said control device comprising a control lever pivotally mounted by pivot means on a structure, said lever being pivotal from a rest position to effect displacement of the mechanism towards a second position, and a second return member which is coupled to said structure at a first attachment and to said lever at a second attachment, the coupling between said second return member and one of said attachments being effected via coupling means, the arrangement being such that said second return member can be -arranged in at least the following three different configurations: -a first configuration in which the second attachment is aligned with the first attachment and the pivot means is disposed beyond said pivot means relative to said first attachment; -a second configuration which is the rest configuration of the lever in which the second attachment is located on one side of a line passing through the first attachment and the' pivot means; and -a third configuration in which the second attachment is located on the opposite side of the line passing through the first attachment and pivot means, and the second return member has the effect of assisting the action of the lever which opposes the action of the first return member and partly neutralises the same; said device further comprising a stop which limits the displacement of the coupling means of the of the second return member in its third configuration.

In preferred embodiments of the invention, one or more of the following can be used: -the stop is mounted on the control lever; -the coupling means of the second return member comprises a flexible rod which extends said second return member which is bent upon engagement with the stop; -the coupling means of the second return member comprises a torsion spring which extends the said second return member and is shaped to form a loop which surrounds the stop with a clearance; -The coupling means of the second return member comprises at least one rigid rod, and is pivotally connected to the second return member and at the second attachment, the rod or (when there are at least two rods) one of the rods being en engageable with the stop; (When there are more than two rods) that rod which engages the stop, is preferably bent: in this case, the stop is preferably constituted by a rounded shaped section of which the radius or'radii of curvature are significantly smaller than that or those of the bend of the bent rod; -the stop can be coaxial to the pivot pin and can optionally comprise the pivot pin itself.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is an elevation of a first embodiment of the contrdl device and associated mechanism; Figure 2 is a view in the direction of arrow F of Figure 1; Figure 3 is an elevation of a second embodiment of the control device; Figure 4 is an elevation of a third embodiment of the control device; Figure 5 is an elevation of a fourth embodiment of the control device; Figure 6 is a view in the direction of arrow G of Figure 5; Figure 7 is an elevation of a fifth embodiment of the control device; and Figures 8 to 10 are curves representing operation of the control device and associated mechanism of Figures 1 and 2.

The constructions described constitute control devices for controlling a mechanism in the form of the clutch of a motor vehicle by means of a clutch pedal 1 which is mounted in pivotal manner on structure 2 of the vehicle by means of a pin 3 with which it is integral.

The clutch 4 comprises a drive housing 5 fixed to a driving shaft 6, and a diaphragm spring 7 having a central portion 7a engageable with a stop 8 mounted in a sliding manner on the input shaft 9 of the gear box and a peripheral portion 7b which can contact a support ring 10 on the clutch disc. Tilting members 11 of spring 7 permit, when the stop 8 forces the central portion 7a in the direction of arrow H, the movement away from the support ring 10 of the peripheral portion 7b. A clutch disc 12 is arranged between a planar face 13 of the drive housing 5 and the support ring 10. A rocking lever 14 which controls the sliding of the stop 8 is mounted in a pivotal manner about a pin 15 on the vehicle structure.

A cable 16 located in a sheath 17 for protection and guidance connects the rocking lever 14 to the pedal 1. A spring 18 comprising a plurality of helical coils 19 and a leg 20 forming a straight rod-like extension of the coils 19 and which can be flexed, is coupled between a pin 21, fixed relative to the vehicle structure and the pedal 1, a hooked end of the leg 20 being engaged in a groove 22 in the body of the pedal. A stop 23 constituted by a pin is fixed to the body of the pedal 1. It should be noted that spring 18, pivot pin 3 and stop 23 have relative positions such that the four following configurations can be obtained: -a rest configuration of pedal 1 in which a line D passing through the pin 21 and groove 22 is located to the left (as viewed in Figure 1) of a line E joining pins 21 and 3, the action of spring 19 being to draw back and maintain pedal 1 in a position corresponding to the absence of action of the stop 8 on the diaphragm spring 7 whereby the disc 12 is in drive-transmitting engagement with the face 13 of the drive housing 5; -a configuration in which the line passing through pin 21 and groove 22a is located at Da and also passes through pin 3, thus coinciding with line E, and which corresponds to a zero action of spring 19 on pedal 1; -a configuration in which the leg 20 of the spring, located at 20b, is just in contact with the stop, which is then located at 23b, and which is not subject to bending, being aligned on the line Db passing through pin 21 and groove 22b; and -a configuration in which the leg 20 of the spring, located at 20c supported on stop 23c and in a bent state and is maintained apart from line Dc joining pin 21 and groove 22c.

It should be noted that in the last and penultimate configurations the action of spring 19 serves to at least partly counter the action of diaphragm spring 7 and to facilitate disengagement. It thus constitutes the assisting force of pedal 1. Further, the angle L subtended between a straight line passing through the pin 3 and the various successive subsequent positions 22a, 22b, 22c of the groove correponding to the three latter configurations defined hereinbefore assumes values of a La Lb and Lc respectively, shown in the curves of Figures 8, 9 and 10. It is clear that angle L represents the extent of pivotal movement of pedal 1 about pin 3.

The embodiment of Figure 3 differs from that of Figures 1 and 2 through the construction of spring 18 which comprises a plurality of helical coils 19 and a leg 24 which is bent back onto itself with a closed loop 25 forming a torsion spring which extends coils 19. Stop 23, which is once again constituted by a pin, is located in the loop 25. During the pivoting of pedal 1, the loop arrives at 25c in a position where, supported on stop 23c, it effectively functions in an elastic manner.

In the embodiment of Figure 4, there is a single spring with helical coils 19 and a separate rigid rod 26. The spring is coupled between pin 21 and the rod 26 on the end 27 of which it is able to pivot. The other end 28 of rod 26 is introduced into groove 22. During the pivoting of pedal 1, the rod moves into a position 26c where it is supported on stop 23c, but it is not aligned with a line passing through pin 21 and its end 27c. The spring is then located at l9c and the groove 22c. In Figure 4, the rod 26 is straight.

The embodiment of Figures 5 and 6 is identical to that of Figure 4, except that the rod 26 is bent at 29 and is supported during the rotation of pedal 1 on pin 3, when it is then located at 26c. Thus, the pin 3 constitutes both the pivot pin of the pedal and a stop for the rod 26. The support area of rod 26c on pin 3 is constituted by the bend located at 29c.

Finally, the embodiment of Figure 7 comprises a spring with helical coils 19, a rigid bent rod 30 having two hooked ends '31 and 32 and a rigid straight rod 33 which also has two hooked ends 34 and 35. The spring is coupled between pin 21 and the end 31 of rod 30, whilst the ends 34, 35 of rod 33 are hooked respectively onto the end 32 of rod 30 and into the groove 22.

The rod 30 faces the pin 3 which it can engage during movement of the pedal. In position 30c, the rod 30 is effectively supported. on pin 3, the other rod 33 and the groove 22 being positioned at 33c and 22c, respectively. It should be noted that the pin 3 has a radius which is much smaller than the radius of the curved portion R of rod 30 whereby the portion R passes around the pin 3 during pivoting of the pedal 1.

Figure 8 illustrates the variation of force P developed by diaphragm spring 7 of Figure 1 as a function of the pivot angle L of the pedal. Thus, P constitutes the thrust necessary for controlling the clutch.

Figure 9 shows the variation in the assistance force R of the spring coupled to pedal 1 (that is the spring 18 with the helical coils 19) as a function of angle L, the force .R being perpendicular to the lever arm extending from the pin 3 to the portion of the pedal contacted by the foot.

Finally, Figure 10 shows the variations as a function of angle L and measured in the same way as force R, of on the one hand force p which corresponds to force P, but is considered in the direction of force R and at pedal 1 and on the other hand of the total force T with which it is necessary to apply to pedal 1 to operate the clutch.

Clearly, T is equal to (p-R).

The following points can be noted from the curves of Figures 9 and 10: -when L varies between 0 and La, the assisting force R is negative in such a way that force T exceeds force p resulting from the isolated action of diaphragm spring 7; -when L varies from La to Lb, the assisting force R increases from 0 to a maximum RMAX in such a way that force T is smaller than force p, the object of the assistance being to reduce the force applied by the operator; Finally, when L varies between Lb and Lc, the assisting force R decreases from RE/IAX and in the same way p decreases, but T becomes substantially constant (slight increase).

Thus, without assistance the, operator would have had to act on pedal 1 with a force given by curve p as a function of angle L, thus with a very variable force, whilst with assistance 'the curve of the forces becomes T, on the one hand leading to forces below the maximum force PMAX due to the action of diaphragm spring 7 and on the other hand leading to a much more progressive variaiton of forces T than that of force p.

However, between Lb and Lc, force R drops which, due to the concomitant drop of p, means that T can be kept sub stantially constant. The reduction of R from L=Lb is naturally due to the support ing of leg 20 on stop 23 and to the partial neutralizaiton of the action of spring 19 which results therefrom. If stop 23 was not provided, force R would have con tinued to increase (curve S) beyond L=Lb, whilst force T would have decreased very rapidly (curve U).

Thus, the importance of stop 23 and the member with which it cooperates is very apparent. The cooperating member is the straight leg 20 of Figures 1 and 2, the torsion spring of Figure 3, the rod 26 of Figures 4, 5 and 6 and the rods 30 and 33 of Figure 7.

In any particular case, the embodiment to be chosen will be dependent on the de sired curve R and therefore on the charac teristic curve T of the clutch spring, which may be a diaphragm spring or any other suitable type of spring.

Each embodiment leads to an assisting force R which varies in accordance with a curve similar to that of Figure 9, but which is characteristic of the particular embodi ment.

Thus, in the embodiment of Figures 1 and 2, the limitation of the assisting force of the tension spring on the pedal at the end of its travel is determined by the leg 20 of the spring bearing on stop 23 and by the leg then flexing.

In the embodiment of Figure 3, the limi tations of the assistng force of the tension spring on the pedal at the end of travel is determined by the inside of loop 25, dis posed on the upper branch of spring 18, bearing against stop 23, the loop then work ing in torsion.

In the embodiment of Figure 4, the limitation of the assisting force of the coil spring on the pedal at the end of travel is determined by rod 26 which is articulated on the spring by its end 27, bearing against stop 23. Thus, this rod then limits the de flection of the spring. It is to be noted that in the construction shown, the rod is sufficiently rigid to prevent it from bend ing when at 26c it bears on the stop 23c.

The limitation of the assisting force of the coil spring of Figures 5 and 6 on the pedal at the end of travel is determined by rod 26 bearing on pivot pin 3 of the pedal and which constitutes the stop.

Finally, the limitation of the assisting force of the coil spring in the embodiment of Figure 7 is determined by the two rods 30 and 33. The curved rod 30 bears on 'pin 3 which forms the stop. Due to its double articulation, the curved rod 30 moves around pin 3, thus limiting the de flection of the spring at the end of pivotal movement of pedal 1 The described device makes it possible with simple means to adapt the curve of the assistance force R, and thus to the resulting force T, which is required to be applied to the clutch pedal.

Although the control device has been described herein with reference to the control of a clutch mechanism the control device can be used for controlling other mechanisms, for example brake mechanisms.

In the embodiments described, the provision of the stop enables the characteristic of the force which is required to be applied to the pedal to be more uniform and not liable to relatively sudden variation.

WHAT WE CLAIM IS: - 1. A control device operatively connected to a mechanism for controlling said mechanism against the action of a first return member which tends to return the mechanism to a first position, said control device comprising a control lever pivotally mounted by pivot means on a structure, said lever being pivotal from a rest position to effect displacement of the mechanism towards a second position, and a second return member which is coupled to said structure at a first attachment and to said lever at a second attachment, the coupling between said second return member and one of said attachments being effected via coupling means, the arrangement being such that said second return member can be arranged in at least the following three different configurations: -a first configuration in which the second attachment is aligned with the first attachment and the pivot means is disposed beyond said pivot means relative to said first attachment; -a second configuration which is the rest configuration of the lever in which the second attachment is located on one side of a line passing through the first attachment and the pivot means; and -a third configuration in which the second attachment is located on the opposite side of the line passing through the first attachment and the pivot means, and the second return member has the effect of assisting the action of the lever which opposes the action of the first return member and partly neutralises the same; said device further comprising a stop which limits the displacement of the coupling means of the second return member in its third configuration.

2. A control device according to claim 1, wherein the stop is mounted on the control lever.

3. A control device according to claim 1 or claim 2, wherein the coupling means comprises a resilient rod which forms an extension of the second return member and which is resiliently bent upon engage ment with the stop.

4. A control device according to claim 1 or claim 2, wherein the coupling means comprises a torsion spring which forms an extension of the said second return member and which is shaped to form a loop which surrounds the stop with a clearance.

5. A control device according to claim 1 or claim 2, wherein the coupling means comprises at least one rigid rod and is pivotally connected to the second return means and to the control lever at the second attachment, said rod being engageable with the stop.

6. A control device according to claim 5, wherein the coupling means comprises at least two said rods which are pivotally connected, one of said rod being bent and being engageable with the stop in the zone of the bend.

7. A control device according to claim 6, wherein the stop comprises a rounded section, the radius or radii of curvature of which is substantially smaller than that or those of the bend of the bent rod.

8. A control device according to any one of the preceding claims, wherein the stop is co-axial with the pivot means.

9. A control device according to claim 8, wherein the stop comprises the pivot means.

10. A control device according to any one of claims 1 to 9, wherein the second return member is a coil spring.

11. A control device according to any one of claims 1 to 10, wherein the control lever is a control pedal of a motor vehicle, and the mechanism is a clutch or brake of the vehicle.

12. A control device substantially as hereinbefore described with reference to Figures 1 and 2, or Figures 1 and 2 as modified by Figure 3, Figure 4, Figures 5 and 6, or Figure 7 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. with simple means to adapt the curve of the assistance force R, and thus to the resulting force T, which is required to be applied to the clutch pedal. Although the control device has been described herein with reference to the control of a clutch mechanism the control device can be used for controlling other mechanisms, for example brake mechanisms. In the embodiments described, the provision of the stop enables the characteristic of the force which is required to be applied to the pedal to be more uniform and not liable to relatively sudden variation. WHAT WE CLAIM IS: -

1. A control device operatively connected to a mechanism for controlling said mechanism against the action of a first return member which tends to return the mechanism to a first position, said control device comprising a control lever pivotally mounted by pivot means on a structure, said lever being pivotal from a rest position to effect displacement of the mechanism towards a second position, and a second return member which is coupled to said structure at a first attachment and to said lever at a second attachment, the coupling between said second return member and one of said attachments being effected via coupling means, the arrangement being such that said second return member can be arranged in at least the following three different configurations: -a first configuration in which the second attachment is aligned with the first attachment and the pivot means is disposed beyond said pivot means relative to said first attachment; -a second configuration which is the rest configuration of the lever in which the second attachment is located on one side of a line passing through the first attachment and the pivot means; and -a third configuration in which the second attachment is located on the opposite side of the line passing through the first attachment and the pivot means, and the second return member has the effect of assisting the action of the lever which opposes the action of the first return member and partly neutralises the same; said device further comprising a stop which limits the displacement of the coupling means of the second return member in its third configuration.

of rod 33 are hooked respectively onto the

end' 32 of rod 30 and into the groove 22.

The rod 30 faces the pin 3 which it can engage during movement of the pedal. In position 30c, the rod 30 is effectively supported on pin 3, the other rod 33 and the groove 22 being positioned at 33c and 22c, respectively. It should be noted that the pin- 3 has a radius -r which is much smaller than the radius of the curved portion R of rod 30 whereby the portion R passes around the pin 3 during pivoting of the pedal 1.

Figure 8 illustrates the variation of force P developed by diaphragm spring 7 of Figure as a-function of the pivot angle L of the pedal. Thus, P constitutes the thrust necessary for controlling the clutch.

Figure 9 shows the variation in the assistance force R of the spring coupled to pedal 1 (that is the spring 18 with the helical coils 19)has a function of angle L, the force R being perpendicular to the lever arm extending from the pin 3 to the portion of the pedal contacted by the foot.

Finally, Figure 10 shows the variations as a function of angle L and measured in the same. way as force R, of on the one hand force p which corresponds to force Pj but is considered in the direction of force R and at pedal 1 and on the other hand of the total force T with which it is necessary to, apply to pedal 1 to operate the clutch.

Clearly, T is equal to (p-"R).

The following points can be noted from the curves of Figures 9 and 10: -when L varies between 0 and La, the assisting force R is negative in such a way that force T exceeds force p resulting from the isolated action of diaphragm spring 7; -when L ,varies from La to Lb, the assisting force R increases from 0 to a maximum RMAx in such a way that force T is smaller than force p, the object of the assistance being to reduce-the force applied by the operator; Finally, when L varies between Lb and Lc, the assisting force R decreases from RMAx and in the same way p decreases, but T becomes substantially constant (slight increase).

Thus, without assistance the . operator would have had to act on pedal 1 with a force given by curve p as a function of angle L, thus with a very variable force, whilst with assistance the curve of the forces becomes T, on the one hand leading to forces below the maximum force PMAX due to the action of diaphragm spring 7 and on the other hand leading to a much more progressive variaiton of forces T than that of force p.

However, between Lb and Lc, force R drops which, due to the concomitant drop of p, means that T can be kept substantially constant. The reduction of R from L=Lb is naturally due to the supporting of leg 20 on stop 23 and to the partial neutralizaiton of the action of spring 19 which results therefrom. If stop 23 was not provided, force R would have continued to increase (curve S) beyond L=Lb, whilst force T would have decreased very rapidly (curve U).

In any particular case, the embodiment to be chosen will be dependent on the desired curve" R and therefore on the characteristic curve T of the clutch spring, which may be a diaphragm spring or any other suitable type of spring.

Each embodiment leads to an assisting force R which varies in accordance with a curve similar to that of Figure 9, but which is characteristic of the particular embodiment.

In the embodiment of Figure 3, the limitations of the assistng force of the tension spring on the pedal at the end of travel is determined by the inside of loop 25, disposed on the upper branch of spring 18, bearing against stop 23, the loop then working in torsion.

In the embodiment of Figure 4, the limitation of the assisting force of the coil spring on the pedal at the end of travel is determined by rod 26 which is articulated on the spring by its end 27, bearing against stop 23. Thus, this rod then limits the deflection of the spring. It is to be noted that in the construction shown, the rod is sufficiently.rigid to prevent it from bending when at 26c it bears on the stop 23c.

The limitation of the assisting force of the coil spring of Figures 5 and 6 on the -pedal at the end of travel is determined by rod 26 bearing on pivot pin 3 of the pedal and which constitutes the stop.

Finally, the limitation of the assisting force of the coil spring in the embodiment of Figure 7 is determined by the two rods 30 and 33. The curved rod 30 bears on pin 3 which forms the stop. Due to its double articulation, the curved rod 30 moves around pin 3, thus limiting the deflection of the spring at the end of pivotal movement of pedal 1.

The described device makes it possible with simple means to adapt the curve of the assistance force R, and thus to the resulting force T, which is required to be applied to the clutch pedal.

WHAT WE CLAIM IS: -

4. A control device according to claim 1 or claim 2, wherein the coupling means comprises a torsion spring which forms an extension of the said second return member and which is shaped to form a loop which surrounds the stop with a clear ance.

5. A control device according to claim 1 or claim 2, wherein the coupling means comprises at least one rigid rod and is pivotally connected to the second return means and to the control lever at the second attachment, said rod being engage able with the stop.