FR2757015A1 - MACHINE COMPRISING A DRIVE MOTOR AND A ROTATING BLADE - Google Patents

Abstract

The machine includes a coupling device that allows the blade to be stopped even when the engine is running. A safety bracket (8) and a pivoting control lever (16) are provided for actuating the coupling device. A stopper (23) which can be actuated by the safety clip (8) can be mechanically engaged with the control lever (16) by means of a stopper device. Application in particular to lawn mowers.

Description

The invention relates to a machine comprising a drive motor

  and a rotary blade, in particular a lawn mower, the blade being connectable to or operatively separated from the drive motor by means of a coupling device and a safety stirrup and a control pivot lever being provided for actuating the coupling device. Motorized machines are known which are equipped with electric motors or also with internal combustion engines. In particular, the machines with internal combustion engines comprise between the cutting tool and the drive motor a coupling device which can be put into service automatically or by means of a control element by the user. These coupling devices serve to stop the tool, in particular rotating blades, when the drive motor is running or to facilitate starting thereof. Especially in lawnmowers, there is known as a blade stop which includes a control lever acting on the coupling device. A safety stirrup or stop element is provided so that the coupling device is not inadvertently actuated, but only intentionally so that the blade is rotated, and when it is released, the driving member and the The driven member of the coupling device is automatically out of engagement and the blade is braked. Such a stop blade is useful in lawnmowers for example to cross paths, in the presence

soil inequalities or the like.

  The present invention aims to create a machine of the type as specified in the preamble and whose actuating mechanism for performing the coupling or release of a structure

  simple and reliable operation.

  This object solved, in a machine comprising a drive motor and a rotary blade in that there is provided a stop member which can be actuated by the safety stirrup can be mechanically engaged with the lever of command by means of a

detent device.

  According to an advantageous embodiment of the invention, the stop member is shaped as a ratchet movable longitudinally by the safety stirrup. This stop member preferably comprises at one end a hole in which without play a pin fixed to the safety stirrup. Thus, the displacement stroke of the stop member is exactly defined according to the actuation of the safety stirrup, so that the cooperation with the control lever is functionally reliable. The stopper is preferably made of plastic material and has an annular segment-shaped slot spaced from the hole for the spindle so that it exists in this area.

a corresponding elasticity.

  One of the ends of the stop member is preferably slidably mounted in a guide element and it is in this case advantageously the end of the stop member which is not intended to be connected to the safety bracket. The guide element makes it possible to obtain that the stop member occupies a position defined with respect to the

  control lever along a linear travel path.

  To make the connection by locking catch, the stop member comprises at the end mounted in the guide element a laterally projecting heel, which enters the pivoting path of a radial protuberance of the control lever and who can snap behind it. It is advantageous, in order to obtain an effective engagement and capable of reliably withstanding the acting restoring forces, that the radial protuberance has on the side facing the stop member at least one sliding surface shaped as a ramp, arranged in an arcuate manner. circle, on which the heel is in sliding support and engages at the end of the ramp. The arcuate arrangement of the sliding path corresponds to the pivoting movement of the radial protuberance relative to the heel of the stop member, heel which is held at a determined position. The ramp provides a progressive lifting movement in the axial direction of the axis of rotation of the control lever, so that the force to be exerted for the actuation of the latter is limited. The engagement of the heel at the end of the ramp results in a relative movement of the stop member and the control lever in the direction of the axis of rotation, so that the heel grips reliably behind the ramp and holds the control lever

reliably to the acquired position.

  It would be possible, to generate the relative movement between the stop member and the control lever in the direction of the axis of rotation of the latter, to mount this lever movable between limits on its axis of rotation and the load with a spring in the direction of engagement of the detent device. However, it is much simpler to make the end of the stop member which comprises the heel so that it can undergo a deflection or lateral flexion relative to its longitudinal axis and be resiliently reset to its original shape. . To this end, the conformation and / or the choice of the plastic material of the organ

  stop to create a certain elasticity in flexion.

  The ramp preferably forms an arc at an angle of between 30 and 50 ° and the height of the ramp is 5 to 10 mm, preferably about 7 mm. It is advantageous for the stop member and the control lever to be able to be simply put out of engagement for the clearance, to also provide a ramp in this direction of movement so that two ramps oriented in opposite directions are arranged. on the radial protuberance at different radial distances from the pivot axis of the control lever. In addition, the ramps advantageously have sliding surfaces of at least approximately the same length and height, the ratio of the length of the sliding surfaces to the height of the ramps being

advantageously 2: 1.

  A guide flange disposed in the direction of the length of the guide member extends over a portion of the stroke of the stop member so that it is guided along a line prescribed at inside of this element. Means are preferably provided to prohibit movement of the stop member by action on the control lever so that it can not be moved in the direction of release without the safety stirrup has been previously activated. These means preferably consist of a hook-shaped protuberance which comprises on the one hand the stop member at the end supporting the heel and, on the other hand, the inner side of the guiding element, these protuberances s' nesting in the manner of claws when the stop member is subjected to a force in the direction of the torque. Thus, the actuation of the safety stirrup and the control lever in the reverse sequence can also be prohibited. The safety stirrup is preferably pivotally mounted, the axes of rotation of this stirrup and the control lever being parallel. The guide element, the safety stirrup and the control lever are arranged on a common guide arm, the fixing points or the mounting pins

  preferably being arranged on a line at a distance from one another.

  An exemplary implementation of the invention will be described in more detail with reference to the accompanying drawings in which: FIG. 1 is a schematic representation of a lawn mower equipped with a drive motor, FIG. An elevational view of the actuating device of the coupling system, Figure 2b is a section of the stop member and its guide member along the line II-I! FIGS. 3a to 3f illustrate the individual parts of the actuating device of the coupling system, FIGS. 4a and 4b show the device for actuating the coupling system at a position of availability and in view of FIGS. 5a to 7b show the three-position movements of the control lever and the corresponding plan view of the stop member, FIGS. 8a to 10b illustrate the device of FIG. actuation of the three-position coupling system of the movement sequence upon release of the safety calliper and the corresponding plan views of the stop member and FIG. 11 is a representation of the forces acting on the

kinematic levers.

  FIG. 1 shows a lawn mower 1 which is displaceable on wheels 3 and comprises a drive motor 2 which drives not only the cutting blade, but also if necessary at least one of the wheels 3 by means of a corresponding coupling device. A guide arm 4 attached to a casing 9 of the mower 1 comprises two parallel longitudinal members 4 'and 4 "which are connected by a yoke 4 * formed in a plate 5, in which the operating elements 6 such as the joystick the throttle adjustment mechanism, that of engaging the driving wheels and the control lever of the coupling of the blade, is arranged close to the stirrup 4 * between the longitudinal members 4 'and 4 ". A coupling stirrup 7 and a safety stirrup 8 are pivotally mounted, also close to the stirrup 4 *, about an axis parallel to the direction of the length of the plate 5 and can be

  actuated against the force of a return spring.

  FIG. 2a shows a device 10 for actuating a coupling device, this actuating device being placed in a housing 11 placed on the upper part of the spar 4 '. A Bowden control 12 enters this housing 11, its cable 14 being provided with a spring 13 for compensation of the elongation and its end 14 'being bent in the shape of a hook and being hooked in a hole 15 of a control lever 16. The latter comprises a handle 17 which overflows on the lower side of the housing 11 and is therefore accessible to the user. The control lever 16 is pivotally mounted with its handle on an axis 18 around a rotation axis DH, the extreme position of the lever 16 being defined for the clearance of the blade by an abutment surface 19 which bears against a sleeve 20 This is disposed on a bent portion 8 'of the safety stirrup 8. This bent portion 8' is perpendicular to the direction of the length of the spar 4 'and is pivotally mounted in the latter

around the axis of rotation DB.

  A rod 21, which is preferably fastened by welding to the safety stirrup 8, close to the axis of rotation DB of the latter, comprises a bent pin 22 which is parallel to the bent portion 8 'of the stirrup 8. This pin 22 penetrates into a hole made at one end 23 'of a stop member 23. It is shaped as a longitudinally displaceable pawl, comprising a central portion 23 * and the other end 23 ". is guided in a longitudinal hole 26 of a corresponding element 27. The guide element 27 is fixedly attached to the spar 4 'The stop member 23 has at the end 23' a heel 24 protruding laterally and penetratingly in the path of a radial protuberance 25

  come molding with the control lever 16.

  Figure 2b shows in section the stop member 23 and its guide member 22. This representation shows that the guide member 27 is fixed by means of a screw 28 passing perpendicularly through the spar 4 '. The longitudinal opening 26 has on the side facing the end 23 'a delimiting wall 40 which extends only to a shallow depth so that a cavity 49 is formed next to it. The end 23 "of the stop member 23 at which the heel 24 is located is located in the longitudinal opening 26 of the guide member 27. At the position shown in Figure 2b, the body of stop 23 is about half of its length in the guide member 27. The central portion 23 * of the stop member 23, which is located between the two ends 23 'and 23 ", is substantially thinner than its thickened ends and penetrates into the cavity 49 provided next to the wall of

delimitation 40.

  3a shows individually the safety stirrup 8 which comprises the bent portion 8 'intended for its mounting and the bent rod 21 necessary for assembly with the stop member and comprising the spindle

22 entering the latter.

  3b shows individually the control lever 16. It comprises the handle 17 already described and which is integrally molded with its mounting portion 29. A hole 30, by means of which the lever 16 is pivotally mounted on the axis 18 shown FIG. 2a is located in the mounting portion 29. The hooking hole of the cable of the Bowden control, as well as the abutment surface 19, which determines the extreme position of the control lever 16 in the state of clearance, are located between the handle 17 and the mounting portion 29. The radial protuberance 25, which came from molding with the mounting portion 29, is provided for cooperation with the stop member. Stop surfaces 46 and 47 are formed on the protrusion 25, act in the circumferential direction and are on different radii with respect to the axis of rotation DH. The side of the protrusion 25 which is turned towards the stop member comprises oblique arrival and departure surfaces in the form of

  ramps 31, 32 which are better visible in Figure 3c.

  Figure 3c is a view - on a slightly enlarged scale - in the direction of the arrow III of Figure 3b. It shows that two oblique surfaces in opposite directions, which form the ramps 31 and 32, are provided on the rear side of the radial protuberance 25. These ramps 31 and 32 are in an arc around the center of the hole 30, as shown in FIG. 3b in broken lines, the ramp 31 being at a greater radial distance from the center of the hole 30 than the ramp 32. The length b of the ramps 31, 32 corresponds to about twice their height a, so as to limit the forces

actuation kits.

  Figure 3d shows individually the stop member 23 in the form of a pawl. Its central portion 23 * is located between the ends 23 'and 23 ", the first of these having a height significantly greater than the second A hole 33 of circular section, below which is located at a short radial distance from the ring-shaped slot 34 is located in the end 23 ', the laterally projecting heel 24 is at the end 23 "and a hook-shaped protrusion 35 is placed in front of the front side of the end 23" . Function

  this protuberance 35 will be described in more detail later.

  Figure 3e shows the guide member 27 which includes a spar holder arm 42 and two parallel rods 36 and 37 which are oriented in the direction of the length of the spar and thus provide a defined positioning thereon. A guide frame 39, within which the longitudinal opening 26 is formed, is above the rod 36; this opening is open to the position shown in Figure 3e on the front side and the back side, as clearly visible in Figure 2b. While the longitudinal opening 26 is closed on the right side, in the representation of Figure 3e, by the attachment arm 42, the delimiting wall 40 extends on the opposite side only over part of the total depth of the guide member 27, so as to form the cavity 49 (as shown in Figure 2b). Thus, the central portion 23 * of the stop member 23 can enter the guide frame 39 so that the end 23 "is inside the longitudinal opening 26. The frame 39 has on the adjacent side of the rod 36 a guide flange 41 which extends only over a portion of the length of the longitudinal opening 26 and ends at a predetermined distance in front of the attachment arm 42. This comprises a protuberance 43 in the form of a hook which penetrates into the longitudinal opening 26 and which is disposed at a height which is above the protuberance 35 of the stop member 23. A hole 38 which is perpendicular to the orientation rods 36, 37 and which is in the attachment arm 42 serves to accommodate the fixing screw 28 which is shown in Figure 2b, Figure 3f illustrates an end 44 of a sheath 45 of the Bowden control 12 which represents the Figure 2a The cable 14 coming out of the end 44 of the sheath 45 comprises, upstream of its end 14 'serving for attachment in a hole of the control lever, a spring 13

compensation of elongation.

  Figures 4a and 4b correspond essentially to Figures 2a and 2b and the individual representations of Figures 3a to 3f, so that the same parts have identical references. However,

  components are partially in a modified relative position.

  As clearly shown in Figure 4a, the safety stirrup 8 occupies a position to which it has pivoted relative to the stirrup 4 * of the spar, that is to say that it has pivoted around the bent portion 8 ' serving as a pin, therefore around the axis of rotation DB. As a result of this pivoting movement, the spindle 22 of the bent rod 21 of FIG. 4a has been moved to the left, of course to the same extent

stop 23.

  As shown in particular in Figure 4b, the heel 24 projecting laterally at the end 23 "is at this position of the stop member 23 at the other end position inside the longitudinal opening 26 of the guide member 27. Thus, the heel 24 is at a radial distance from the axis of rotation DH of the control lever 16 on which is also the ramp 32 of the radial protuberance 25. The lowest point of the ramp 32 is at this end of the radial protuberance 25, seen in the circumferential direction, so

  that the heel 24 does not block the control lever 16.

  It is thus possible, as shown in Figure 5a, to rotate the control lever 16 by means of the handle 17 in the counterclockwise direction about the axis of rotation DH, so that the cable 14 of the control Bowden is pulled over a determined length out of the sheath 45. During this pivoting movement of the control lever 16, the radial protuberance 25 moves along the heel 24 and then the oblique ramp 32 moves the end 23 "of the stop member 23 further in the longitudinal opening 26 with respect to the depth of the guide member 27. FIG. 5b clearly shows that the central portion 23 * of the stop member 23 undergoes with respect to the direction its length, a deflection or flexion which is possible due to the characteristics of its material.As soon as the radial protuberance 25 of the control lever 16 has passed completely beyond the heel 24 (Figure 6a), it can reach behind the stop surface 46, of fate e the central portion 23 * of the stop member 23 can return elastically rearward, as shown in Figure 6b, and therefore this heel 24 enters the path of the protrusion 25. When the handle 17 the control lever 16 is released, the latter rotates slightly backwards, so that the abutment surface 46 bears against the heel 24, as shown in Figure 7a. Since in this position, two flat surfaces of the heel 24 and the protrusion 25 abut against each other, the heel 24 forms a transverse key which prevents the control lever 16 from being brought back to the side. back by the recall force of the Bowden command

12 acting on him.

  To release the cutting blade vis-à-vis the drive motor, it is necessary to release the safety stirrup 8 so that it moves away from the stirrup 4 * of the spar. Even when the safety stirrup 8 is released involuntarily, it comes into operation and then it rotates around its bent end 8 ', that is to say around the axis of rotation DB, as shown in FIG. 8a and therefore it moves to the right the pin 22 of the bent rod 21. Thus, the stop member 23 is moved until it bears against the attachment arm 42, so that it occupies its extreme position. At this position of the stop member 23, the heel 24 is at a radial distance from the axis of rotation DH on which the ramp 31 is located. The latter being arranged in the opposite direction with respect to the ramp 32, the heel 24 is in abutment against the ramp 31 and it slides along thereof while the control lever 16 rotates in the clockwise direction. As also shown in FIG. 8a, when the safety stirrup 8 is released, the inside of the end 23 'of the stop member is against the spar, so that this end 23' also serves elastic stop. When the position of FIG. 8a is reached, the slope of the ramp pushes the end 23 "of the stop member 23 into the longitudinal opening 26,

  as shown in Figure 8b.

  As soon as the radial protuberance 25 of the control lever 16 has passed completely beyond the heel 24, this lever 16 reaches the extreme position represented by FIG. 9 and at which the abutment surface 19 bears against the sleeve 20. stop member 23 can elastically resume its initial shape, so that the heel 24 enters the

  pivoting trajectory of the protuberance 25.

  Since it is necessary to move only the control lever 16 by pulling the handle 17, the abutment surface 47 of the protuberance 25 reaches the heel 24, as shown in Figures a and 10b, and it exerts on the body stop 23 a force acting in the direction of the torque. This causes the end 23 "of the stop member 23 to rise slightly, so that the hook-shaped protuberance 35 engages with the hook-shaped protuberance 43 and thus the stop member. 23 in this position, it is also not possible to obtain a displacement of the stop member 23 by subsequent actuation of the safety stirrup 8, so that an actuation of the latter and of the control lever 16 in the sequence

  the opposite of that provided for correct operation is excluded.

  Figure 11 shows the actuating device 10 with indication of the direction of the acting forces. So, F1 represents the strength of

  recall that the Bowden command 12 transmits to the control lever 16.

  This restoring force F1 is assisted by the heel 24, because the abutment surface 46 of the protuberance 25 bears against it. Only a small fraction of the overall force acting on different vectors acts in the direction of the length of the stop member 23, as shown by the arrows F 2a representing the forces. The forces acting in the directions F2 and F2b can not cause a displacement of the stop member 23 in the direction of its length. As the proportion of the forces F 2 a is therefore relatively small, low retention forces in the direction F 3 suffice to hold the control lever 16 at the position at which the blade is coupled to the drive motor, particularly considering the arm

  lever that forms the safety stirrup 8.

Claims (10)

  1. Machine comprising a drive motor and a rotary blade, in particular a lawnmower (1), the blade being connectable to the driving motor (2) or can be separated therefrom functionally by means of a device coupling and a safety stirrup (8) as well as a pivoting control lever (16) being provided for the actuation of the coupling device, characterized in that a stop member (23) can be actuated by the safety bracket (8) is provided and can be mechanically engaged with the lever of   control (16) by means of a detent device.   2. Machine according to claim 1, characterized in that the stop member (23) is designed as a pawl being movable longitudinally by the safety stirrup (8) and preferably comprises at one end (23 ') a hole (33) into which a pin goes without play   (22) attached to said safety stirrup (8).   3. Machine according to claim 2, characterized in that one (23 ") of the ends of the stop member (23) is slidably mounted in a guide member (27), the stop member ( 23) preferably having, at the end (23 ") mounted in the guide member (27), a laterally projecting heel (24) which penetrates into the pivoting path of a radial protuberance (25). ) of the control lever (16) and   who can hang behind it.   4. Machine according to claim 3, characterized in that the radial protuberance (25) has on the side facing the stop member (23) at least one sliding surface shaped as a ramp (31, 32) arranged in arc of a circle and against which the heel (24) can slide and snap at the end of the ramp, the ramp (31, 32) preferably extending over an arc angle of between 30 'and 50' and the height of the ramp (a) being between 5 mm and 10 mm and being in particular about 7 mm.   5. Machine according to claim 4, characterized in that the end (23 ") of the stop member (23) which comprises the heel (24) can undergo a deflection or lateral flexion by contribution to its axis of symmetry   longitudinal and can return to its initial shape elastically.   Machine according to either of Claims 4 and 5,   characterized in that two ramps (31, 32) oriented in opposite directions and placed at different radial distances from the axis of rotation (DH) of the control lever (16) are provided on the radial protuberance (25), and two ramps (31, 32) comprise sliding surfaces having lengths (b) and heights (a) at least substantially equal, the ratio of the length (b) of the sliding surfaces to the height (a) of the ramps preferably 2: 1.   7. Machine according to claim 4, characterized in that a guide flange (41) oriented in the direction of the length is arranged in the corresponding element (27) and extends only over a part of the   stroke of movement of the stop member (23).   8. Machine according to claim 3, characterized in that the stop member (23) comprises at the end (23 ") which carries the heel (24) a protrusion (35) hook-shaped and the inner side the guiding element (27) also comprises a protuberance (43) in the form of a hook, these two protuberances fitting one into the other in the manner of claws when the stop member (23) receives a push into the direction of the torque.   9. Machine according to any one of the claims   previous, characterized in that the safety stirrup (8) is pivotally mounted, the axes of rotation (DB and DH) of the safety stirrup and the lever control being parallel.   10. Machine according to any one of claims 3 to 9,   characterized in that the guide element (27), the safety stirrup (8) and the control lever (16) are arranged on a guide arm (4), the fixing points and the mounting axes being placed preferably on a   line remote from each other.