LINEAR ACTUATOR WITH SHOCK DAMPING

Abstract

SHOCK-DAMPING LINEAR ACTUATOR Linear actuator (1) comprising a moving thrust element (2) that can be moved linearly along a longitudinal direction (II) within an external tube (3), said moving thrust element (2) being movable by actuation means (4) with helical linkage (5) between a retracted position and at least one extended position relative to said external tube (3), the moving thrust element (2) extending between a proximal end (2a) and a distal end (2b) and comprising a proximal section (2c) subjected to displacement by the actuation means (4) with helical linkage (5). A connecting body (10), fixedly attached to a free end of the proximal section (2c), dampens sudden thrusts and / or sudden pulls. Figure to be published with the abbreviation: Fig. 2

Description

Title of the invention: LINEAR ACTUATOR WITH SHOCK DAMPING TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of linear actuators usable to generate linear motion.

[0002] A linear actuator AL is known as illustrated in [Fig. 1], comprising a push element EMP that can be moved linearly along a longitudinal direction DL in an external tube TE, said push element EMP being movable by actuation means MA with helical linkage LH between a retraction position and at least one extension position relative to said external tube TE, the push element EMP extending between a proximal end EP and a distal end ED and comprising a proximal section TP forced into displacement by the actuation means MA with helical linkage LH.

[0003] The helical link LH is here of the type ball screw VB having a nut EC indexed in rotation in the external tube TE and movable by sliding in said external tube TE when a threaded rod TF is driven in rotation by a motor M. It should be noted that the drive connection linking the motor M to the threaded rod TF is not represented here precisely.

[0004] In the present invention, the helical linkage may comprise a component other than a ball screw but operating on the screw / nut principle. For example, a satellite roller screw or a trapezoidal screw may be used.

[0005] During certain uses, the EMP push mobile element is subjected to sudden pulls (tending to move the EMP push mobile element towards its extension position) and / or sudden pushes (tending to move the EMP push mobile element towards its retraction position).

[0006] These sudden pulls and / or pushes generate shocks that propagate from the distal end of the moving thrust element EMP to the helical joint LH. This presents a significant risk of damage to the helical joint LH. Description of the invention

[0007] One problem proposed by the present invention is to effectively limit the risks of degradation of the helical linkage actuation means of a linear actuator in the event of sudden pulls and / or sudden pushes.

[0008] To achieve this object and others, the invention proposes a linear actuator comprising a moving thrust element that can be moved linearly along a longitudinal direction in an external tube, said moving thrust element being movable by helical linkage actuation means between a retraction position and at least one extension position with respect to said external tube, the moving thrust element extending between a proximal end and a distal end and comprising a proximal section forced into displacement by the helical linkage actuation means; According to the present invention, said moving thrust element further comprises: - a connecting body, adapted to be fixedly attached to a free end of the proximal section, and comprising: a. a first transverse traction surface oriented towards the proximal end of the moving thrust element, b. a first transverse thrust surface oriented towards the distal end of the moving thrust element, - a distal section suitable for coupling to a load to be moved, arranged to slide along the longitudinal direction relative to the connecting body, and comprising: a. a second transverse traction surface oriented towards the distal end of the moving thrust element, b. a second transverse thrust surface oriented towards the proximal end of the moving thrust element, and in that said linear actuator comprises: a. a compressible tensile damping element, arranged longitudinally between the first transverse tensile surface and the second transverse tensile surface, and / or b. a compressible thrust damping element, arranged longitudinally between the first transverse thrust surface and the second transverse thrust surface.

[0009] In the linear actuator according to the invention, if a sudden pull occurs on the moving thrust element (tending to move the moving thrust element towards its extension position), the compressible traction damping element is compressed between the first transverse traction surface and the second transverse traction surface, and thus absorbs at least part of the shock.

[0010] If a sudden thrust occurs on the moving thrust element (tending to move the moving thrust element towards its retraction position), the compressible thrust damping element is compressed between the first transverse thrust surface and the second transverse thrust surface, and thus absorbs at least part of the shock.

[0011] Consequently, the risks of degradation of the helical linkage actuation means of the linear actuator are effectively limited.

[0012] The compressible thrust and / or tension damping element always works in compression to absorb shocks. This effectively limits the risk of degradation of the compressible thrust and / or tension damping element, particularly when the compressible thrust and / or tension damping element is made of an elastomer-type material.

[0013] In applications that give rise to little or no sudden pulling, it may suffice to provide the compressible thrust damping element.

[0014] In applications that give rise to little or no sudden thrusts, it may suffice to provide the compressible tension damping element.

[0015] In applications involving sudden pulls and pushes, a compressible tension damping element and a compressible push damping element may be provided. In such a case, the compressive properties of the compressible tension damping element and the compressible push damping element may be identical or different, depending on the intensities and frequencies of the sudden pulls and pushes.

[0016] In a first embodiment of the present invention, it can be provided that: - the connecting body comprises a transverse wall carrying the first transverse tension surface and the first transverse thrust surface on either side of said transverse wall, - the distal section comprises: a. a proximal body comprising the second transverse traction surface, b. a distal body comprising the second transverse thrust surface, c. connecting means engaged by sliding through the transverse wall of the connecting body and rigidly coupling the proximal body to the distal body.

[0017] Advantageously, in a first embodiment of said first embodiment, the connecting means may comprise a connecting rod passing through the center of the transverse wall of the connecting body. Such a structure allows the use of compressible thrust and / or tension damping elements in the form of a ring or bushing, and thus partially deforming radially inwards during compression. This promotes good compactness.

[0018] Advantageously, the linear actuator may include rotational indexing means between the connecting body and the distal body of the distal section. These indexing means may preferably include keys allowing longitudinal sliding of the distal body of the distal section relative to the connecting body. The indexing means eliminate the need for indirect indexing of the connection. helical by constraining the design of the element actuated by the moving thrust element.

[0019] Advantageously, in a second variant of said first embodiment, the connecting means may comprise a plurality of connecting rods eccentric radially with respect to the center of the transverse wall of the connecting body. The indexing means again avoid having to provide indirect indexing of the helical connection by constraining the design of the element actuated by the moving thrust element.

[0020] Such a structure also allows the use of compressible thrust and / or tension damping elements in the form of a solid cylinder when the intensity of the shocks requires it. However, the compressible thrust and / or tension damping elements will deform radially outwards during compression, so that the compactness is reduced.

[0021] Preferably, it can be provided that: - the connecting body comprises a cylindrical side wall in which the distal body is guided by sliding motion, - the proximal section of the moving thrust element comprises a cylindrical side-walled tube in which the proximal body of the distal section is guided by sliding motion.

[0022] Such sliding guides promote shock damping by compression of the compressible tension damping element and / or the compressible thrust damping element.

[0023] In a second embodiment of the present invention, it can be provided that: - the connecting body comprises: a. a proximal transverse wall, bearing the first transverse thrust surface, b. a distal transverse wall, bearing the first transverse traction surface, c. a cylindrical side wall, - the distal section comprises: a. a proximal body disposed longitudinally between the proximal transverse wall and the distal transverse wall, and carrying the second transverse traction and thrust surfaces, said proximal body being guided by sliding motion by the cylindrical lateral wall of the connecting body, b. a distal body, c. connecting means engaged by sliding through the distal transverse wall of the connecting body and rigidly coupling the proximal body to the distal body.

[0024] The subset formed by the connecting body and the distal section is more easily integrable into an existing linear actuator.

[0025] Preferably, the means of connection may include: - a connecting rod extending from and away from the proximal body, comprising a threaded free end and passing through the center of the distal transverse wall of the connecting body, - an internally threaded housing provided in the distal body, suitable for receiving by screwing the free threaded end of the connecting rod.

[0026] Advantageously, the linear actuator may include rotational indexing means between the connecting body and the distal body of the distal section. These indexing means avoid the need for indirect indexing of the helical linkage by constraining the design of the element actuated by the moving thrust element.

[0027] Preferably, it can be provided that: - the connecting means comprise a section with a non-circular cross-section, - the distal transverse wall of the connecting body comprises a through passage with a non-circular cross-section in which the section with a non-circular cross-section of the connecting means is slidably engaged. - said non-circular cross sections cooperate by interference of shapes to prohibit any relative rotation around the longitudinal direction between the connecting body and the distal body of the distal section.

[0028] Such indexing is reliable and compact.

[0029] Advantageously, the compressible tension damping element and / or the compressible thrust damping element can be, for example: - a block made of an elastomeric material, - a spring, - a Belleville washer. SUMMARY DESCRIPTION OF THE DRAWINGS

[0030] Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, made in relation to the accompanying figures, among which:

[0031] [Fig-1] Fig. 1 is a schematic longitudinal cross-sectional view of an actuator linear according to prior art;

[0032] [Fig.2] The [Fig.2] is a schematic longitudinal cross-sectional view of a first variant of a first embodiment of a linear actuator according to the present invention, with a moving push element in the retracted position;

[0033] [Fig.3] The [Fig.3] is a schematic perspective view of the linear actuator of the [Fig.2], with a moving thrust element in the extended position;

[0034] [Fig.4] The [Fig.4] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig.2], in the absence of push or pull on the moving push element;

[0035] [Fig.5] The [Fig.5] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig.2] when a sudden push occurs on the moving push element (tending to move the moving push element towards its retraction position);

[0036] [Fig.6] The [Fig.6] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig.2] when a sudden pull occurs on the moving thrust element (tending to move the moving thrust element towards its extension position);

[0037] [Fig.7] The [Fig.7] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig.2] in an alternative intended to receive mainly only sudden thrusts;

[0038] [Fig.8] The [Fig.8] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig.2] in an alternative intended to receive mainly only sudden pulls;

[0039] [Fig.9] The [Fig.9] is a schematic cross-sectional view of the linear actuator along the PT1 plane identified in figures 4 to 8;

[0040] [Fig. 10] The [Fig. 10] is a schematic longitudinal sectional and detail view of a second variant of the first embodiment of a linear actuator according to the present invention;

[0041] [Fig. 11] The [Fig. 11] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 10] when a sudden push occurs on the moving thrust element;

[0042] [Fig. 12] The [Fig. 12] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 10] when a sudden pull occurs on the moving thrust element;

[0043] [Fig. 13] The [Fig. 13] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 10] in an alternative intended to receive mainly only sudden thrusts;

[0044] [Fig. 14] The [Fig. 14] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 10] in an alternative intended to receive mainly only sudden pulls;

[0045] [Fig. 15] The [Fig. 15] is a schematic cross-sectional view of the linear actuator along the PT2 plane identified in figures 10 to 14;

[0046] [Fig. 16] The [Fig. 16] is a schematic longitudinal sectional and detail view of a second embodiment of a linear actuator according to the present invention;

[0047] [Fig. 17] The [Fig. 17] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 16] when a sudden push occurs on the moving thrust element;

[0048] [Fig. 18] The [Fig. 18] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 16] when a sudden pull occurs on the moving thrust element;

[0049] [Fig. 19] The [Fig. 19] is a schematic longitudinal sectional and detail view of the linear actuator of the [Fig. 16] in an alternative intended to receive mainly only sudden thrusts;

[0050] [Fig. 20] [Fig. 20] is a schematic longitudinal cross-sectional and detailed view of the linear actuator of [Fig. 16] in an alternative configuration intended to receive primarily only sudden pulls; and

[0051] [Fig.21] The [Fig.21] is a schematic cross-sectional view of the linear actuator along the PT3 plane identified in figures 16 to 20. DESCRIPTION OF PREFERRED IMPLEMENTATION METHODS

[0052] When identical numerical references are used in several figures, embodiments, variants or alternatives of the invention, these numerical references designate identical or similar elements in each of the figures, embodiments or variants.

[0053] Figures 2 to 9 illustrate a first variant of a first embodiment of linear actuator 1 according to the present invention.

[0054] In figures 2 to 6, this is a first alternative, capable of damping both sudden pushes and sudden pulls.

[0055] In [Fig.7], this is a second alternative, capable of damping only sudden thrusts.

[0056] In [Fig.8], this is a third alternative, capable of absorbing only sudden pulls.

[0057] It can be seen more particularly on [Fig.2] that the linear actuator 1 comprises a moving thrust element 2 that can be moved linearly along a longitudinal direction II in an external tube 3, said moving thrust element 2 being movable by actuation means 4 with helical linkage 5 between a retraction position ([Fig.2]) and at least one extension position ([Fig.3]) with respect to said external tube 3.

[0058] The moving thrust element 2 extends between a proximal end 2a and a distal end 2b, and includes a proximal section 2c stressed in displacement by the actuation means 4 with helical linkage 5.

[0059] Here, the helical linkage 5 is of the ball screw type having a nut 6 indexed for rotation in the external tube 3 and movable by sliding within said external tube 3 when a threaded rod 7 is driven in rotation by a motor 8. It should be noted that the drive connection 9 linking the motor 8 to the threaded rod 7 is not represented here precisely because its structure can be arbitrary within the framework of the present invention.

[0060] It should be noted that the helical linkage 5 may include a component other than a ball screw but operating on the screw / nut principle. For example, a helical linkage 5 of the satellite roller screw type, or of the trapezoidal screw type, may be used.

[0061] It is clearer in [Fig. 4] that the moving thrust element 2 further comprises a connecting body 10, adapted to be fixedly attached to a free end of the proximal section 2c. In practice, the proximal section 2c terminates in a tubular section Tl which receives the connecting body 10 by means of a screw connection. To this end, the connecting body 10 has an external thread which engages by screwing with an internal thread formed in the tubular section Tl.

[0062] The connecting body 10 comprises: - a first transverse traction surface STT1 oriented towards the proximal end 2a of the moving thrust element 2, - a first transverse thrust surface STP1 oriented towards the distal end 2b of the moving thrust element 2.

[0063] The moving thrust element 2 further comprises a distal section 2d adapted to be coupled to a load to be moved, arranged to slide along the longitudinal direction II relative to the connecting body 10, and comprising: - a second transverse traction surface STT2 oriented towards the distal end 2b of the moving thrust element 2, - a second transverse thrust surface STP2 oriented towards the proximal end 2a of the moving thrust element 2.

[0064] In the alternative illustrated in [Fig. 4], the linear actuator 1 simultaneously comprises: - a compressible tensile damping element 11, arranged longitudinally between the first transverse tensile surface STT1 and the second transverse tensile surface STT2, - a compressible thrust damping element 12, arranged longitudinally between the first transverse thrust surface STP1 and the second transverse thrust surface STP2.

[0065] In practice, the connecting body 10 comprises a transverse wall 13 carrying the first transverse tension surface STT1 and the first transverse thrust surface STP1 on either side of said transverse wall 13.

[0066] The distal 2d segment comprises: - a proximal body 14 comprising the second transverse traction surface STT2, - a distal body 15 comprising the second transverse thrust surface STP2, - connecting means 16 engaged by sliding through the transverse wall 13 of the connecting body 10 and rigidly coupling the proximal body 14 to the distal body 15.

[0067] More precisely, the connecting means 16 comprise a connecting rod 17 passing through the center of the transverse wall 13 of the connecting body 10. The connecting rod 17 is hollow and receives a screw 18 which is received by screwing into a threaded housing 19 provided in the distal body 15.

[0068] The compressible tension damping elements 11 and thrust damping elements 12 have a general annular shape to allow passage of the connecting means 16.

[0069] The compressible tensile damping element 11 is fixed to the second transverse tensile surface STT2. The compressible thrust damping element 12 is fixed to the second transverse thrust surface STP2.

[0070] The connecting body 10 and the distal body 15 of the distal section 2d are coupled in rotation by rotational indexing means 20. It can be seen more particularly on [Fig.9], which is a cross-section along the transverse plane PT1, that the rotational indexing means 20 comprise two keys 20a and 20b which allow longitudinal sliding of the distal body 15 relative to the connecting body 10, while blocking any relative rotation around the longitudinal direction II between the distal body 15 and the connecting body 10.

[0071] The shock damping during the operation of the linear actuator 1 is explained by means of figures 5 and 6.

[0072] In [Fig.5], the movable thrust element 2 receives on its distal body 15 a thrust in the longitudinal direction II and illustrated by the arrow P. Under the effect of this thrust, the distal body 15 slides relative to the connecting body 10. The compressible thrust damping element 12 is then compressed between the first STP1 and second STP2 transverse thrust surfaces, and its radial deformation (in the direction of and away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the thrust.

[0073] In [Fig.6], the moving thrust element 2 receives on its distal body 15 a tension along the longitudinal direction II and illustrated by the arrow T. Under the effect of this tension, the distal body 15 slides relative to the connecting body 10, taking the proximal body 14 with it. The compressible tension damping element 11 is then compressed between the first STT1 and second STT2 transverse tension surfaces, and its radial deformation (in the direction of and away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the tension.

[0074] The alternative in figures 5 and 6 thus makes it possible to cushion the shocks both during sudden pushes and during sudden pulls.

[0075] Figure 7 illustrates an alternative linear actuator 1 primarily subjected to sudden thrusts. Only one compressible damping element is provided, namely the compressible thrust damping element 12, interposed between the first STP1 and second STP2 transverse thrust surfaces. When the compressible thrust damping element 12 is at rest (held between the first STP1 and second STP2 transverse thrust surfaces without being compressed, or only very slightly), the first STT1 and second STT2 transverse tension surfaces are in contact with each other.

[0076] In the alternative of [Fig.7], sudden push damping is provided, but sudden pull damping is not provided.

[0077] Figure 8 illustrates an alternative linear actuator 1 primarily subjected to sudden pulls. Only a single compressible damping element is provided, namely the compressible tension damping element 11 interposed between the first STT1 and second STT2 transverse tension surfaces. When the compressible tension damping element 11 is at rest (held between the first STT1 and second STT2 transverse tension surfaces without being compressed, or only very slightly), the first STT1 and second STT2 transverse thrust surfaces are in contact with each other.

[0078] In the alternative of [Fig.8], sudden pulls are damped, but sudden pushes are not damped.

[0079] Figures 10 to 15 illustrate a variant of the first embodiment, according to three alternatives illustrated respectively in Figures 10 to 12, in [Fig. 13] and finally in [Fig. 14].

[0080] This variant differs in particular from the variant illustrated in Figures 4 to 9 in that the connecting means 16 comprise a plurality of connecting rods 17a to 17h eccentric radially with respect to the center of the transverse wall 13 of the connecting body 10 (see in particular [Fig. 15], which is a cross-section along the transverse plane PT2). The connecting rods 17a to 17h are received in corresponding threaded recesses 15a to 15h formed in the distal body 15. Such connecting means 16 allow longitudinal sliding of the distal body 15 relative to the connecting body 10, while blocking any relative rotation about the longitudinal direction II between the distal body 15 and the connecting body 10.

[0081] In the variant of figures 10 to 15, the compressible tension damping elements 11 and thrust elements 12 have a generally solid cylindrical shape.

[0082] The compressible tensile damping element 11 is fixed to the second transverse tensile surface STT2 (by means of a fixed joint). The damping element compressible thrust 12 is fixed to the second transverse thrust surface STP2 (by fixed connection).

[0083] The shock damping during the operation of the linear actuator 1 is explained by means of figures 11 and 12.

[0084] In [Fig. 11], the movable thrust element 2 receives on its distal body 15 a thrust in the longitudinal direction II and illustrated by the arrow P. Under the effect of this thrust, the distal body 15 slides relative to the connecting body 10. The compressible thrust damping element 12 is then compressed between the first STP1 and second STP2 transverse thrust surfaces, and its radial deformation (away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the thrust.

[0085] In [Fig. 12], the moving thrust element 2 receives on its distal body 15 a tension along the longitudinal direction II and illustrated by the arrow T. Under the effect of this tension, the distal body 15 slides relative to the connecting body 10, taking the proximal body 14 with it. The compressible tension damping element 11 is then compressed between the first STT1 and second STT2 transverse tension surfaces, and its radial deformation (away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the tension.

[0086] The alternative in figures 11 and 12 thus makes it possible to cushion the shocks both during sudden pushes and during sudden pulls.

[0087] Figure 13 illustrates an alternative linear actuator 1 primarily subjected to sudden thrusts. Only a single compressible damping element is provided, namely the compressible thrust damping element 12 interposed between the first STP1 and second STP2 transverse thrust surfaces. When the compressible thrust damping element 12 is at rest (held between the first STP1 and second STP2 transverse thrust surfaces without being compressed, or only very slightly), the first STP1 and second STP2 transverse traction surfaces are in contact with each other.

[0088] In the alternative of [Fig.13], sudden push damping is provided, but sudden pull damping is not provided.

[0089] Figure 14 illustrates an alternative linear actuator 1 primarily subjected to sudden pulls. Only a single compressible damping element is provided, namely the compressible tension damping element 11 interposed between the first STT1 and second STT2 transverse tension surfaces. When the compressible tension damping element 11 is at rest (held between the first STT1 and second STT2 transverse tension surfaces without being compressed, or only very slightly), the first STT1 and second STT2 transverse thrust surfaces are in contact with each other.

[0090] In the alternative of [Fig.14], sudden pulls are damped, but sudden pushes are not damped.

[0091] In all variants and alternatives of the first embodiment, it can be seen that: - the connecting body 10 has a cylindrical side wall 10a in which the distal body 15 is guided by sliding, - the proximal section 2c of the moving thrust element 2 includes a tube 21 with a cylindrical side wall 21a in which the proximal body 14 of the distal section 2d is guided by sliding.

[0092] The variants and alternatives of the first embodiment thus require a tube 21 with a specific conformation (cylindrical side wall 21a of guidance followed by a tubular section Tl of larger internal diameter and internally threaded).

[0093] Figures 16 to 21 illustrate a second embodiment, according to three alternatives illustrated respectively in Figures 16 to 18, in [Fig. 19] and finally in [Fig. 20].

[0094] In this second embodiment, it can be seen more particularly in [Fig. 16] that the connecting body 10 comprises: - a proximal transverse wall 22, bearing the first transverse thrust surface STP1, - a distal transverse wall 23, bearing the first transverse traction surface STT1, - a cylindrical side wall 10a.

[0095] Still on [Fig. 16], we see that the distal 2d segment comprises: - a proximal body 14 arranged longitudinally between the proximal transverse wall 22 and the distal transverse wall 23, and carrying the second transverse traction surfaces SST2 and thrust surfaces STP2, said proximal body 14 being guided by sliding by the cylindrical lateral wall 10a of the connecting body 10, - a distal body 15, - connecting means 16 engaged by sliding through the distal transverse wall 23 of the connecting body 10 and rigidly coupling the proximal body 14 to the distal body 15.

[0096] More specifically, the connecting means 16 comprise: - a connecting rod 17 extending from and away from the proximal body 14, comprising a threaded free end 170 and passing through the center of the distal transverse wall 23 of the connecting body 10, - an internally threaded housing 24 provided in the distal body 15, suitable for receiving by screwing the threaded free end 170 of the connecting rod 17.

[0097] The distal body 15 is thus rigidly coupled (in translation as well as in rotation) to the proximal body 14.

[0098] Here again, rotational indexing means 20 are provided between the connecting body 10 and the distal body 15 of the distal section 2d. It can be seen more particularly in [Fig. 21], which is a cross-section along the transverse plane PT3, that: - the connecting means 16 comprise a section T2 (of the connecting rod 17) with a non-circular cross-section, - the distal transverse wall 23 of the connecting body 10 includes a through passage 23a with a non-circular cross-section in which the section T2 with a non-circular cross-section of the connecting means 16 is slidably engaged, - said non-circular cross sections of the section T2 and the through passage 23a cooperate by interference of shapes to prohibit any relative rotation around the longitudinal direction II between the connecting body 10 and the distal body 15 of the distal section 2d (via the proximal body 14 to which the distal body 15 is rigidly coupled).

[0099] The second embodiment requires a tube 21 with a simpler shape than the first embodiment. Here, only an internally threaded tubular section Tl is needed to receive the connecting body 10 by screwing.

[0100] The compressible tension damping elements 11 and thrust damping elements 12 again have a generally annular shape to allow passage of the connecting means 16 (compressible tension damping element 11) and to increase compactness through deformation that occurs partly radially inwards during compression. If compactness is not critical, the compressible tension damping element 11 can be in the form of a solid cylinder (as in Figures 10 to 12 and 14).

[0101] The compressible tensile damping element 11 is fixed to the second transverse tensile surface STT2. The compressible thrust damping element 12 is fixed to the second transverse thrust surface STP2.

[0102] The shock damping during the operation of the linear actuator 1 is explained by means of figures 17 and 18.

[0103] In [Fig. 17], the movable thrust element 2 receives on its distal body 15 a thrust in the longitudinal direction II and illustrated by the arrow P. Under the effect of this thrust, the distal body 15 slides relative to the connecting body 10. The compressible thrust damping element 12 is then compressed between the first STP1 and second STP2 transverse thrust surfaces, and its radial deformation (in the direction of and away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the thrust.

[0104] In [Fig. 18], the moving thrust element 2 receives on its distal body 15 a traction in the longitudinal direction II and illustrated by the arrow T. Under the effect of this tension, the distal body 15 slides relative to the connecting body 10, taking the proximal body 14 with it. The compressible tension damping element 11 is then compressed between the first STT1 and second STT2 transverse tension surfaces, and its radial deformation (in the direction of and away from the longitudinal direction II) thus dampens part of the stresses induced on the helical connection 5 by the tension.

[0105] The alternative in figures 17 and 18 thus makes it possible to cushion the shocks both during sudden pushes and during sudden pulls.

[0106] Figure 19 illustrates an alternative linear actuator 1 primarily subjected to sudden thrusts. Only a single compressible damping element is provided, namely the compressible thrust damping element 12 interposed between the first STP1 and second STP2 transverse thrust surfaces. When the compressible thrust damping element 12 is at rest (held between the first STP1 and second STP2 transverse thrust surfaces without being compressed, or only very slightly), the first STP1 and second STP2 transverse traction surfaces are in contact with each other.

[0107] In the alternative of [Fig.19], sudden push damping is provided, but sudden pull damping is not provided.

[0108] Figure 20 illustrates an alternative linear actuator 1 primarily subjected to sudden pulls. Only a single compressible damping element is provided, namely the compressible tension damping element 11 interposed between the first STT1 and second STT2 transverse tension surfaces. When the compressible tension damping element 11 is at rest (held between the first STT1 and second STT2 transverse tension surfaces without being compressed, or only very slightly), the first STT1 and second STT2 transverse thrust surfaces are in contact with each other.

[0109] In the alternative of [Fig.20], sudden pulls are damped, but sudden pushes are not damped.

[0110] The compressible tension damping element 11 and / or the compressible thrust damping element 12 may in particular be: - a block of an elastomeric material, - a spring, - a Belleville washer.

[0111] The compressible tension damping elements 11 and thrust damping elements 12 may be of the same nature (for example, both made of an elastomeric material) or of different natures (for example, one made of an elastomeric material and the other a spring). Their compressibility may also be identical or different, depending in particular on the direction, frequency and intensity of shocks to be endured when using linear actuator 1.

[0112] The present invention is not limited to the embodiments that have been explicitly described, but includes the various variants and generalizations contained within the scope of the following claims.

Claims

1. Demands A linear actuator (1) comprising a moving thrust element (2) that can be moved linearly along a longitudinal direction (II) in an external tube (3), said moving thrust element (2) being movable by helical-linked actuation means (4) (5) between a retracted position and at least one extended position relative to said external tube (3), the moving thrust element (2) extending between a proximal end (2a) and a distal end (2b) and comprising a proximal section (2c) subjected to displacement by the helical-linked actuation means (4) (5), characterized in that said moving thrust element (2) further comprises: - a connecting body (10), adapted to be fixedly attached to a free end of the proximal section (2c), and comprising: a. a first transverse traction surface (STT1) oriented towards the proximal end (2a) of the moving thrust element (2), b. a first transverse thrust surface (STP1) oriented towards the distal end (2b) of the moving thrust element (2), - a distal section (2d) suitable for coupling to a load to be moved, arranged to slide along the longitudinal direction (II) relative to the connecting body (10), and comprising: a. a second transverse traction surface (STT2) oriented towards the distal end (2b) of the moving thrust element (2), b. a second transverse thrust surface (STP2) oriented towards the proximal end (2a) of the moving thrust element (2), and in that said linear actuator (1) comprises: a. a compressible tensile damping element (11), arranged longitudinally between the first transverse tensile surface (STT1) and the second transverse tensile surface (STT2), and / or b. a compressible thrust damping element (12), arranged longitudinally between the first transverse thrust surface (STP1) and the second transverse thrust surface (STP2).

2. Linear actuator (1) according to claim 1, characterized in that: - the connecting body (10) comprises a transverse wall (13) carrying the first transverse traction surface (STT1) and the first transverse thrust surface (STP1) on either side of said transverse wall (13), - the distal section (2d) comprises: a. a proximal body (14) comprising the second transverse traction surface (STT2), b. a distal body (15) comprising the second transverse thrust surface (STP2), c. connecting means (16) engaged by sliding through the transverse wall (13) of the connecting body (10) and rigidly coupling the proximal body (14) to the distal body (15).

3. Linear actuator (1) according to claim 2, characterized in that the connecting means (16) comprise a connecting rod (17) passing through the center of the transverse wall (13) of the connecting body (10).

4. Linear actuator (1) according to claim 3, characterized in that it comprises rotational indexing means (20) between the connecting body (10) and the distal body (15) of the distal section (2d), preferably by means of keys (20a, 20b) allowing longitudinal sliding of the distal body (15) of the distal section (2d) relative to the connecting body (10).

5. Linear actuator (1) according to claim 2, characterized in that the connecting means (16) comprise a plurality of connecting rods (17a-17h) eccentric radially with respect to the center of the transverse wall (13) of the connecting body (10).

6. Linear actuator (1) according to any one of claims 2 to 5, characterized in that: - the connecting body (10) comprises a cylindrical side wall (10a) in which the distal body (15) is guided by sliding motion,

7.

8.

9. - the proximal section (2c) of the moving thrust element (2) includes a tube (21) with a cylindrical side wall (21a) in which the proximal body (14) of the distal section (2d) is guided by sliding. Linear actuator (1) according to claim 1, characterized in that that : - the connecting body (10) comprises: a. a proximal transverse wall (22), bearing the first transverse thrust surface (STP1), b. a distal transverse wall (23), bearing the first transverse traction surface (STT1), c. a cylindrical side wall (10a), - the distal segment (2d) comprises: a. a proximal body (14) arranged longitudinally between the proximal transverse wall (22) and the distal transverse wall (23), and carrying the second transverse traction (STT2) and thrust (STP2) surfaces, said proximal body (14) being guided by sliding by the cylindrical lateral wall (10a) of the connecting body (10), b. a distal body (15), c. connecting means (16) engaged by sliding through the distal transverse wall (23) of the connecting body (10) and rigidly coupling the proximal body (14) to the distal body (15). Linear actuator (1) according to claim 7, characterized in that the connecting means (16) comprise: - a connecting rod (17) extending from and away from the proximal body (14), comprising a threaded free end (170) and passing through the center of the distal transverse wall (23) of the connecting body (10), - an internally threaded housing (24) provided in the distal body (15), suitable for receiving by screwing the threaded free end (170) of the connecting rod (17). Linear actuator (1) according to claim 8, characterized in that it comprises rotational indexing means (20) between the connecting body (10) and the distal body (15) of the distal section (2d).

10. Linear actuator (1) according to claim 9, characterized in that: - the connecting means (16) comprise a section (T2) with a non-circular cross-section, - the distal cross-wall (23) of the connecting body (10) comprises a through passage (23a) with a non-circular cross-section in which the section (T2) with a non-circular cross-section of the connecting means (16) is slidably engaged, - said non-circular cross-sections cooperate by interference of shapes to prohibit any relative rotation around the longitudinal direction (II) between the connecting body (10) and the distal body (15) of the distal section (2d).

11. Linear actuator (1) according to any one of claims 1 to 10, characterized in that the compressible tension damping element (11) or the compressible thrust damping element (12): - is a block of an elastomeric material, - is a spring, - is a Belleville washer.

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