FR2583491A1 - Transmission mechanism, in particular for windscreen wiper, and windscreen wiper device equipped with such a mechanism - Google Patents

Abstract

The mechanism for transmission between a rotary driveshaft 3 and a connecting rod 5 for controlling an alternating oscillating movement comprises linking means L between the rotary shaft 3 and the connecting rod 5 comprising a cam 6 which interacts with at least one roller 7, these linking means L making it possible to ensure an oscillating movement of predetermined angular amplitude, when the rotary shaft rotates in the normal direction of rotation, and to ensure an increase in the angular amplitude of the movement when a stopping of operation is ordered. The linking means L comprise a crank 8 fixed to the shaft 3 and at least one linking piece J between the crank 8 and the connecting rod 5, mounted so as to move relative to the crank 8. The linking piece J carries the roller 7 while the cam 6 remains immobile relative to a framework. The relative position of the linking piece J and of the crank 8 is controlled by the interaction of the cam 6 and of the roller 7.

Description

TRANSMISSION MECHANISM, PARTICULARLY FOR WINDSCREEN WIPERS,
AND WIPER DEVICE EQUIPPED WITH SUCH A MECHANISM.

 The invention relates to a transmission mechanism, in particular for a wiper, between a rotary drive shaft and a connecting rod, or the like, for controlling an alternative oscillating movement.

 The transmission mechanisms targeted by the invention are of the type which comprise means of connection between the rotary shaft and the connecting rod comprising a cam which cooperates with at least one roller, or equivalent, these means of connection being arranged to ensure an oscillation movement of predetermined angular amplitude, when the rotary shaft rotates in the normal direction of rotation, and to ensure an increase in the angular amplitude of the movement, when an operating stop is commanded.

 In the case where such a mechanism is used for a wiper control, the latter take an erased position or parking position ", corresponding to the maximum angular amplitude.

 The object of the invention is, above all, to make the transmission mechanisms of the kind defined above such that they respond better than hitherto to the various requirements of practice and in particular such that they are of simple and robust construction . It is further desirable that the number of moving parts of the mechanism be as low as possible.

 According to the invention, a transmission mechanism, in particular for wiper devices, of the type of those mentioned above, is characterized in that the connecting means comprise a crank fixed to the rotary shaft, extending radially , and at least one connecting piece between the crank and the connecting rod, mounted movable relative to the crank, this connecting piece carrying the roller, or the like, while the cam remains stationary, relative to a frame, for the direction normal rotation of the shaft, the relative position of the connecting piece and the crank being controlled by the cooperation of the cane and the roller.

 According to a first embodiment, the piece of.

link is articulated on the crank and forms a rocker.

 The frame has an inner track in which the roller, or equivalent, carried by the rocker, can only enter when the direction of rotation of the rotary shaft is reversed, this roller moving against the outer periphery of the cane. for the normal direction of rotation of the shaft; the rocker is articulated on the crank at a point located in a middle region of said rocker and spaced from the axis of the rotary shaft; the rocker is punished, towards one end, the roller and, towards its other end located on the other side of the joint, of a crank pin for the attachment of lasbielle. The tilting commanded by the cooperation of the roller and the cane track causes an increase in the radial distance between the blade and the axis of the rotary shaft, which leads to an increase in the angular amplitude of the oscillation.

 The crank may have, in plan, a bent shape with two branches substantially at right angles, the point of articulation between the rocker and the crank being located towards the end of the branch remote from the rotary shaft. A pin may be provided on the crank, in the region of connection of the two branches, to liniter the angular movement of the rocker.

 The rocker can be formed by a kind of flat square which, on the side facing the cane, at one end of a branch, the roller and, on the side opposite the cam, towards the end of the other branch , the crank pin, the concavity of this square being turned radially outwards, on the side opposite to the rotary shaft.

 The inner track of the cam is drilled by a sort of groove, notably circular, opening onto the outer surface of the cam through a flared opening; the outer surface of the cam is formed by a cylindrical surface of revolution centered on the axis of the rotary shaft.

 According to another embodiment, the connecting piece, between the crank and the connecting rod, is slidably mounted in the radial direction, on the crank, and forms a slide.

 The cam is formed of two superimposed crowns having coaxial cylindrical interior surfaces, while the roller, or equivalent, carried by the slide, has an axial length sufficient to cooperate with the interior surfaces of the two crowns of the cam; each crown of this cam carries, on its inner surface, a notch; the notches of the two crowns are angularly offset when the rotary shaft rotates in the normal direction so that the roller cannot enter these notches; one of the crowns is mounted fixed relative to a frame, while the other crown can rotate, relative to the first, around the axis of the rotary shaft under the action of drive means, the rotation of the movable crown being such that the two notches come to overlap; when the stop of the operation is commanded, the movable crown is moved so that the two notches are superimposed and that the roller, under the action of elastic means, can enter these notches, the slide undergoing a radial displacement towards the outside.

The elastic means urging the roller can comprise a compression spring placed between a stop located radially inwards and a thrust member which is supported, for example, by a notch in the form of
V, against the axis carrying the roller.

 The drive means of the mobile crown can be constituted by an electromagnet which is kept under tension when the rotary shaft rotates and which is turned off when the movement is stopped.

 The crank can be constituted by a flat blade with rectangular outline provided with a longitudinal median slot opening at the end remote from the rotary shaft and hooked at its other end, while the slide has a cross section substantially in C coming to grip said lare, this slide comprising an axis which crosses the longitudinal slot and which carries, on one side, the roller and on the other the pin for the attachment of the connecting rod.

 The invention also relates to a wiper device comprising a transmission mechanism as defined above.

 The invention consists, apart from the arrangements set out above, of certain other arrangements which will be more explicitly discussed below in connection with particular embodiments described with reference to the attached drawings, but which are in no way limiting. .

 FIG. 1 of these drawings is a diagram illustrating the wiping provided by a windscreen wiper with parking position ".

 Figure 2 is a section along line II-II Figure 3 of a first embodiment of a transmission mechanism according to the invention.

 Figure 3 is a top view, relative to Figure 2, of the mechanism, in its configuration corresponding to the normal direction of rotation of the rotary shaft.

 Figure 4 is a top view, similar to that of Figure 3, of the mechanism in the configuration corresponding to the setting in the "park" position.

 Figure 5 is a section along the line V-V Figure 7 of another embodiment of a mechanism according to the invention.

 Figure 6 is a view along the line VI-VI Figure 5.

 Figure 7 is a partial top view of the mechanism of Figure 5 in a position corresponding to the normal direction of rotation.

 Figure 8, finally, similarly shows in Figure 7, the mechanism in the "park" position.

 The following description relates to the application of transmission mechanisms according to the invention to wiper devices.

 FIG. 1 illustrates the wiping provided by a wiper arm 1 which rotates around an axis 2. During normal operation, the arm 1 performs an alternating oscillation movement between two extreme angular positions A and B forming between they an OC angle. This corresponds to a normal scanning cycle which is obtained by rotation in a determined direction or normal direction of rotation of a rotary drive shaft 3.

 When the scanning stop is commanded, the drive shaft 3 stops in a position such that the arm 1 is in position A. The parking position is automatically controlled after stopping, and the arm 1 goes to the retracted or "park" position represented by P in FIG. 1. When the arm has reached this position P, the movement is stopped. In this "park" position P, the arm and the wiper attached to this arm are generally no longer visible on the windshield or other surface to be wiped and are located, for example, below the extension of the the body.

 A transmission mechanism M is provided between the rotary shaft 3, which is stationary in translation relative to a frame 4, and a connecting rod 5, or the like, for controlling the wiper arm (s) such as 1.

 The transmission mechanism M comprises connecting means L (see FIGS. 2 to 4) between the rotary shaft 3 and the connecting rod 5.

 These connecting means L comprise a cam 6 which cooperates with at least one roller 7, or equivalent.

 These connecting means L are arranged to ensure an oscillation movement of predetermined angular amplitude (movement between positions A and B of Figure 1) when the rotary shaft 3 rotates in the normal direction, and to ensure an increase in the angular amplitude of the movement by reversing the direction of rotation of the shaft 3, when an operating stop is commanded.

The wiper arm 1 then takes the erased position, or "parking" position P corresponding to the maximum angular amplitude.

 The connecting means L comprise a crank 8 fixed on the rotary shaft 3 and extending radially.

According to the embodiment of Figures 2 to 4, this crank 8 is formed by a flat bent piece, coHue visible in Figure 2, and which has two zones 9, 10 located in parallel planes, but separated one on the other in a direction orthogonal to their plane. The zone 9 is blocked on the end of the shaft 3 which may include a fluted frustoconical zone II followed by a threaded part 12. The zone 9 of the crank has a hole suitable for cooperating with the frustoconical zone 11, while a nut 13 screwed onto the part 12 axially pushes the frustoconical surface of the hole made in the zone 9 against the zone 11.

 The zone 10 of the crank 8 is offset from the side opposite to the frame 4 and to the cam 6 so as to be able to pass beyond this cam as visible in FIG. 2.

 In plan, as visible from Figures 3 and 4, the crank 8 has a bent shape with two branches 14, 15 substantially at right angles, each branch having a substantially rectangular shape.

 A connecting piece J, mounted movable relative to the crank 8, is provided between this crank and the connecting rod 5. This connecting piece J carries the roller 7, while the cam 6 remains stationary relative to the frame 4, at least for the normal direction of rotation of the shaft 3.

 The relative position of the connecting piece J and the crank 8 is controlled by the cooperation of the cam 6 and the roller 7.

 According to the embodiment of FIGS. 2 to 4, the connecting piece J forms a rocker 16 articulated on a pivot 17 of axis orthogonal to the mean plane of the crank 8.

The pivot 17 therefore has its geometric axis parallel to that of the shaft 3. The point of articulation formed by this pivot 17 is located towards the end of the branch 15 remote from the rotary shaft 3. A pin 18 is provided on the crank 8 in the region of connection of the two branches 14, 15 to limit the angular movement of the rocker. This pin 18 is offset, angularly, relative to the radius starting from the shaft 3 and passing through the pivot 17.

 The rocker 16 is formed by a kind of flat square which carries, on the side facing the cam 6, at one end of a branch, the roller 7 and, on the side opposite the cam 6, towards the end of the 'other branch, a crank pin 19 for the articulated attachment of the connecting rod 5. The concavity of the bracket formed by the rocker 16 is turned radially outward, on the side opposite to the shaft 3. The roller 7 is preferably rotatably mounted on an axis 20 fixed perpendicular to the rocker 16.

 The cam 6 is formed by a plate fixed to the frame 4 in particular by screws 21. The peripheral surface 22 of the cam 6 is a cylindrical surface coaxial with the shaft 3. The roller 7 rolls outwardly against this surface 22 when the shaft 3 rotates in the normal direction of rotation which, according to the representation in FIG. 3, corresponds to the anticlockwise direction. The cam 6 is provided with a track 23 formed by a groove provided on the face opposite to the frame 4. This groove 23 can be circular and extend over 180 ", the mean radius E of this groove being less than the radius R of the outer peripheral surface 22.

 A wall 24 separates the groove from the exterior surface. The track 23 opens, on the surface 22, by a flared opening 25 limited by two surfaces 26, 27 ensuring a progressive connection between the inner and outer walls of the track 23 and the peripheral surface 22. The opening 25 is substantially diametrically opposite at the end 28 of runway 23.

 When the direction of rotation of the shaft 3 is reversed, the roller 7 can enter the opening 25 and the track 23 as shown in Figure 4, which controls the tilting of the rocker 16 and causes an increase in the distance radial between the crank pin 19 and the axis of the shaft 3. This distance goes from the value h (FIG. 3) to the value H (FIG. 4). This results in an increase in the angular amplitude of the oscillation. The stop of the shaft 3 is controlled when the roller 7 arrives at the end 28 of the track 23; the arm 1 then occupies the position P of FIG. 1.

 The operation of the embodiment of Figures 2 to 4 results immediately from the previous explanations.

 When the shaft 3 rotates in the normal direction of rotation, which corresponds for the representation of FIG. 3 in the counterclockwise direction, the roller 7 moves against the outer peripheral surface 22; the rocker 16 bears against the pin 18 as shown in FIG. 3, the crank pin 19 being located at the minimum distance h from the shaft 3. The brush 1 will oscillate between the positions A and B of FIG. 1.

 The roller 7 crosses the opening 25 practically without shock and without noise. In fact, the inertia of the linkage driven by the crankpin 19 keeps this crankpin in its position for crossing the opening 25.

 When the scanning stop is commanded, the shaft 3 stops in a position such that the brush 1 is in the position A; the roller 7 is then substantially diametrically opposite the opening 25. The reversal of the direction of rotation of the shaft 3 is then automatically controlled and this shaft describes a complete revolution in the opposite direction.

 The crank 8 will therefore describe a complete revolution, clockwise when looking at FIG. 3. During the first half of this revolution, the arm 1 will pass from position A to position B, the effective length (distance between the axis of the shaft 3 and the axis of the crank pin 19) of the crank 8 remaining equal to h.

 The crank 8 continuing its movement clockwise, according to Figure 3, the roller 7 will enter the opening 25 and the rocker 16 will change relative position relative to the crank 8 and take the position shown in Figure 4. The roller 7 rolls against the outer surface 27 of the track 23, and the rocker 16 bears by another area against the pin 18. The effective length of the crank increases and takes the value H.

 At the end of the turn, when the roller 7 arrives in the vicinity of the end 28, the stopping of the shaft 3 is controlled and the arm 1 occupies the "parking" position P of FIG. 1.

 Referring to Figures 5 to 8, one can see another embodiment of the mechanism of the invention.

 Elements identical or playing roles analogous to elements already described with regard to FIGS. 2 to 4 will be designated either by the same references, or by numerical references equal to the sum of the number 100 and the numerical reference used in FIGS. 2 to 4.

 The description of these elements will not be repeated or will be done only very succinctly.

 The connecting piece J between the crank 108 and the connecting rod 105 is slidably mounted, in the radial direction, on this crank, and forms a slide 29. The cam 106 is formed by two crowns 30, 31 superimposed and rotatably mounted. one in relation to the other. The lower ring 31 is fixed to the frame; it is provided with an inner centering flange 32 projecting axially suitable for being received in an annular recess 33 provided on the inner edge of the crown 30. The two superimposed crowns 30, 31 have inner surfaces 34, 35 coaxial cylindrical , centered on the axis of the shaft 103, and of the same radius.

 Each ring 30, 31 carries, on its inner surface, a notch 36, 37 respectively. These two notches are angularly offset, as visible in FIG. 7, when the rotary shaft 103 rotates in the normal direction which, according to FIG. 7 , corresponds counterclockwise.

 Drive means E in particular formed by an electromagnet 38 are provided for controlling a rotation of the movable crown 30 such that the notch 36 comes to align with the notch 37 as shown in FIG. 8, when the stop operation is commanded. Preferably, this alignment of the notches 36, 37 is obtained by cutting off the power supply to the electromagnet 38, while maintaining the angular offset of the notches 36, 37, shown in FIG. 7, is obtained by keeping under tension the electromagnet 38. As shown diagrammatically in FIG. 7, the electromagnet can actuate a rod 39 articulated on an external radial tab 40 carried by the crown 30. The body of the electromagnet 38 is itself - even connected by an articulation to a point of the frame.

 The crank 108, as visible in FIG. 6, is constituted by a flat lare with rectangular outline provided with a longitudinal median slot 41 opening at the far end of the rotary shaft 103 on which the crank 108 is fixed. The slot 41 is closed at its other end. The slide 29 has a substantially C-shaped cross section enclosing the lare forming the crank 108; the curved parts such as 42 (FIG. 6) of the ends of the branches of the slider 29 are engaged under the crank 108 while the region of the slider 29 connecting the curved parts 42 is situated on the side of the crank 108 opposite the cane 106.

 The slide 29 supports an axis 43 orthogonal to its mean plane. The axis 43 carries, on the side opposite to the cam 106, the crank pin 119. This axis 43 crosses the slot 41 and projects into the interior volume of the crowns 30, 31.

The end of the shaft 43, located in the crowns 30, 31, carries the roller 107, rotatably mounted on said axis. This roller 107 has an axial length n sufficient to cooperate simultaneously with the interior surfaces 34, 35 of the two rings; the roller 107 can be formed by the superposition of two elementary rollers. The peripheral dimension of the notches 36, 37 is greater than the diameter of the roller 107 which can thus enter these notches.

 When the two notches 36, 37 are offset, as shown in FIG. 7, the roller 107 cannot enter these notches since it remains in contact with one of the surfaces 35, 34 when it is in line with the 'one of the notches 36, 37.

 On the other hand, when the two notches 36, 37 are aligned, as in the case of FIG. 8, the roller 107 can enter these notches. The axis 43 carries, on the side opposite to the cam 106, the crank pin 119.

 Elastic means S are provided for urging the roller 107 radially outwards in order to push it into the notches 36, 37 when they are superimposed.

 These elastic means S comprise a compression spring 44, disposed below the crank 108, that is to say on the side of the cam 106.

 This spring 44 is mounted in a housing 45 fixed under the crank 108. The bottom of this housing constitutes a stop 46, located radially inwards, for the spring 44. A thrust member 47, formed by a sort of mounted plate sliding radially in the housing 45, is provided between the spring 44 and the axis 43. The end of the thrust member 47 bearing against the axis 43 is constituted by a notch 48 (FIG. 6) in the shape of a V , notably substantially straight. The axis 43 is received in the concavity of the notch 48.

 That said, the operation of the device of Figures 5 to 8 is as follows.

 When the shaft 103 is driven in the intended direction (anti-clockwise direction according to FIG. 7), the electromagnet 38 is energized and keeps the notches 36 and 37 offset one with respect to the 'other.

The roller 107 rolls against the inner surface 34, 35 of the crowns 30 and 31, without being able to enter the notches 36, 37. The crank pin 119 describes a circle of minimum radius around the axis of the shaft 103.

 The wiper blade 1 oscillates between positions A and B in Figure 1.

 When the device is stopped, the shaft 103 stops rotating in a position such that the roller 107 is opposite the notch 37. The brush 1 is then in the position A shown in the figure 1. Furthermore, the power supply to the electromagnet 38 is cut so that the rotation of the crown 30, in the clockwise direction, is controlled by the elastic return means of the electro - magnet 38.

 The notch 36 is superimposed on the notch 37 as shown in FIG. 8.

 The roller 107 can then enter the aligned notches 36, 37, under the action of the spring 44. The crank pin 119 deviates radially from the axis 103, which causes the displacement of the brush 1 (FIG. 1) from the position A at the "park" position P.

 It is clear that the applications of the transmission mechanism according to the invention are not limited to wiper devices but can relate to any alternative oscillation movement with resting in a position situated beyond the range of the oscillations. .

Claims (12)

 1. Transmission mechanism, in particular for a wiper, between a rotary drive shaft and a connecting rod, or the like, for controlling an alternative oscillating movement, which comprises means of connection between the rotary shaft and the connecting rod comprising a cam which cooperates with at least one roller, or equivalent, these connecting means being arranged to ensure an oscillation movement of predetermined angular amplitude, when the rotary shaft rotates in the normal direction of rotation, and for ensuring an increase in the angular amplitude of the movement when an operating stop is commanded, characterized in that the connecting means (L) comprise a crank (8, 108) fixed on the rotary shaft (3, 103) , extending radially, and at least one connecting piece (J) between the crank and the connecting rod (5, 105), mounted movable relative to the crank, this connecting piece (J) carrying the roller (7, 107 ), or the like, while the cam (6, 106) remains stationary , relative to a frame, for the normal direction of rotation of the shaft (3, 103), the relative position of the connecting piece (J) and the crank (8, 108) being controlled by the cooperation of the cam (6, 106) and roller (7, 107).  2. Transmission mechanism according to claim 1, characterized in that the connecting piece (J) is articulated on the crank (8) and forms a rocker (16).  3. Transmission mechanism according to claim 2, characterized in that the cam (6) is provided with a track (23) in which the roller (7) or equivalent, carried by the rocker (16), cannot enter that when the direction of rotation of the rotary shaft (3) is reversed, this roller (7) moving against the outer periphery (22) of the cam (6) for the normal direction of rotation of the shaft (3) , the rocker (16) being articulated on the crank (8) at a point (17) located in a middle region of said rocker and spaced from the axis of the rotary shaft (3), the rocker (16) being provided, towards one end, the roller (7) and, towards its other end situated on the other side of the articulation (17), of a crank pin (19) for the attachment of the connecting rod (5).  4. Transmission mechanism according to claim 2 or 3, characterized in that the crank (8) has, in plan, a bent shape with two branches (14, 15) substantially at right angles, the point of articulation (17 ) between the rocker (16) and the crank (8) being located towards the end of the branch (15) remote from the rotary shaft (3), a pin (18) may be provided on the crank, in the region connecting the two branches (14, 15), to limit the angular movement of the rocker (16).  5. Transmission mechanism according to any one of claims 2 to 4, characterized in that the rocker (16) is formed by a kind of flat bracket which carries, on the side facing the cam (6), to a end of a branch, the roller (7) and, on the side opposite the cam (6), towards the end of the other branch, the crank pin (19), the concavity of this angle being turned radially towards the outside, on the side opposite the rotary shaft (3).  6. Transmission mechanism according to claim 3 or according to all of claim 3 and claim 4 or 5, characterized in that the inner track (23) of the cam (6) is formed by a kind of groove , in particular circular, opening onto the outer surface (22) of the cam (6) by a flared opening (25), this outer surface (22) of the cam being formed by a cylindrical surface of revolution centered on the axis of the 'rotary shaft (3).  7. Transmission mechanism according to claim 1, characterized in that the connecting piece (J), between the crank (108) and the connecting rod (105), is slidably mounted in the radial direction, on the crank (108) , and forms a slide (29).  8. Transmission mechanism according to claim 7, characterized in that the cam (106) is formed of two superimposed rings (30, 31) having inner surfaces (34, 35) coaxial cylindrical, while the roller (107) , or equivalent, carried by the slide (29) has an axial length (n) sufficient to cooperate with the interior surfaces (34, 35) of the two crowns of the cam, each crown (30, 31) bearing, on its interior surface , a notch (36, 37), the notches of the two crowns being angularly offset when the rotary shaft (103) rotates in the normal direction, so that the roller (107) cannot enter these notches, one ( 31) of the crowns being mounted fixed relative to a frame (104), while the other crown (30) can rotate, relative to the first (31), around the axis of the rotary shaft (103) under the action of drive means (E), the rotation of the movable crown (31) being such that the two notches (36, 37) come about when the stop of operation is commanded, the roller (107), under the action of elastic means (S) entering these notches (36, 37), while the slide (29) undergoes a radial displacement towards the outside.  9. Transmission mechanism according to claim 8, characterized in that the elastic means (S) urging the roller (107) comprise a compression spring (44) placed between a stop (46) located radially inward and a thrust member (47) which bears, for example, by a V-shaped notch (48), against an axis (43) carrying the roller (107).  10. Transmission mechanism according to claim 8 or 9, characterized in that the drive means (E) of the movable ring (31) are constituted by an electromagnet (38) which is kept under tension when the rotary shaft (103) rotates and which is switched off when the movement is stopped.  11. Transmission mechanism according to any one of claims 8 to 10, characterized in that the crank (108) is constituted by a flat blade with rectangular outline provided with a median slot (41) longitudinal opening at the end remote from the rotary shaft (103) and closed at its other end, while the slide (29) has a substantially C-shaped cross section enclosing said blade, this slide (29) having an axis (43) which passes through the slot longitudinal (41) and which carries, on one side, the roller (107) and on the other, the crank pin (119) for the attachment of the connecting rod (105).  12. A wiper device characterized in that it comprises a transmission mechanism according to any one of the preceding claims.