DOUBLE CARDAN MECHANICAL LINKAGE DEVICE
The monobloc double cardan mechanical connection device addresses the precision and bulkiness issues of existing devices by using a single-piece construction with a double cardan mechanism, effectively absorbing alignment defects and ensuring precise movement adjustments in optical or optronic instruments.
Patent Information
- Application Number
- FR2023011935
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-11-02
- Publication Date
- 2025-05-09
- Estimated Expiration
- 2043-11-02
AI Technical Summary
Current double cardan mechanical connection devices are not satisfactory for optical or optronic instruments due to lack of precision, bulkiness, and manufacturing tolerances, which lead to imprecision and axial disalignment in transmission systems.
A monobloc double cardan mechanical connection device with a single-piece construction, featuring a first and second longitudinal end with a double cardan mechanism, including end blocks, intermediate blocks, and central films that ensure precise alignment and axial damping while transmitting rotation torque.
The device effectively absorbs alignment and position defects in transmission systems, ensuring precise movement adjustments and maintaining flexibility, thereby enhancing the precision and reliability of optical or optronic instruments.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Title of the invention: DOUBLE CARDAN MECHANICAL CONNECTION DEVICE Technical field of the invention
[0001] The present invention relates to a double-cardan mechanical connection device, and an optical or optronic instrument comprising such a device. Technical background
[0002] An optical or optronic instrument may comprise moving parts and a motor for moving these moving parts. This is for example the case of a lens which can be moved in translation along an axis by means of a motor and a connecting mechanism transforming a rotation of the output shaft of the motor into translational movement of the lens.
[0003] In a camera, for example, in order to ensure its observation precision, all the elements making up the zoom system must be placed very precisely. Some of these mechanical elements, due to too low precision of the physical measuring instruments, cannot meet the positioning specifications of the optical diagram. This leads, in this case, to axial misalignment in the transmission, and thus to inaccuracy of the system.
[0004] In this type of instrument, it is thus useful to use a double cardan device to ensure the mechanical connection of a motor shaft, in order to compensate for misalignments and axial forces while transmitting a rotational torque.
[0005] In the current technique, double cardan mechanical connection devices are not satisfactory. In particular, they do not allow for optimal precision, particularly in adjusting the movements of the moving parts. Furthermore, they are generally formed by assembling several parts which induce precision defects due in particular to the manufacturing and assembly tolerances of the parts. In addition, the known connection devices are generally too bulky and therefore incompatible with the intended application.
[0006] A connecting device must allow precise adjustment even when it is misaligned and must retain a certain flexibility for this adjustment. A connecting device that is too rigid would risk breaking and would therefore be too fragile.
[0007] There is therefore a need for a double cardan mechanical connection device which makes it possible to solve at least some of the problems and disadvantages mentioned above. Summary of the invention
[0008] The present invention provides a double cardan mechanical connection device, which device having a general shape elongated along an axis of elongation and comprising:
[0009] - a first longitudinal end of mechanical connection,
[0010] - a second longitudinal mechanical connection end, and
[0011] - a double cardan between the first and second longitudinal ends,
[0012] characterized in that the first and second ends are formed from a single part with the double cardan so that the connecting device is in one piece, and in that the double cardan comprises:
[0013] - a first end block which is rigidly connected to the first long end tudinal,
[0014] - a second end block which is rigidly connected to the second long end tudinal,
[0015] - a first intermediate block which is connected to the first end block by a first intermediate film of matter,
[0016] - a second intermediate block which is connected to the second end block by a second intermediate film of material, the first and second intermediate blocks being arranged between the first and second end blocks, the first and second intermediate films being located in a first plane of symmetry of the double gimbal which passes through the axis of elongation, and
[0017] - a central block which is located between the first and second intermediate blocks and which is connected to these first and second intermediate blocks respectively by first and second central films of material, these first and second central films being located in a second plane of symmetry of the double gimbal which passes through the axis of elongation and which is perpendicular to the first plane of symmetry.
[0018] The device according to the invention makes it possible to absorb alignment and position defects in the transmission between two elements while transmitting a force such as a torque and guaranteeing axial damping.
[0019] Double cardan refers to the fact that the device can be replaced by a system of two cardan joints placed one after the other. A cardan joint allows the transmission of an angular rotation of two elements, such as two shafts, whose geometric axes converge. A double cardan joint therefore ensures an angular rotation of two parallel axes that are not necessarily aligned. The term monobloc refers to the fact that the system is composed of only one piece. The films are thin walls that allow the device to twist along different axes. The films thus ensure the monobloc device's function as a double cardan joint. The different blocks prevent plastic deformation of the geometry.
[0020] The geometric shapes are defined so as to meet the needs of mechanical resistance both statically and dynamically.
[0021] The device according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another: the device comprises a third plane of symmetry of the double gimbal, which is perpendicular to the elongation axis and which passes between the first and second intermediate blocks and in the middle of the central block; the first and second end blocks have identical shapes and dimensions, and / or the first and second intermediate blocks have identical shapes and dimensions; the first and second end blocks have in section in said second plane a generally triangular shape of which a base is connected to one of the longitudinal ends, and a vertex is connected to one of the intermediate films; the first and second intermediate blocks each have a general disc or cylinder shape centered on the elongation axis; each of the end blocks is separated from the nearest intermediate block by a distance measured along the axis of elongation, which is less than or equal to 1 mm, and which is the smallest on the side of the longitudinal end to which the end block is connected; the intermediate blocks are separated from each other by a distance measured along the axis of elongation, which is less than or equal to 1 mm. the distance measured is the smallest at one of the faces of the disc or cylinder, or at the faces of the disc or cylinder; the distance between the intermediate blocks is less than a measured distance along the axis of elongation between the central block and each of the intermediate blocks; the first and second intermediate blocks each have a first recess in which one of the end blocks is at least partially engaged, and a second recess in which said central block is at least partially engaged; the first and second recesses are located on two opposite faces of the disc or cylinder; the films of material are each connected to the bottom of one of the recesses, by two connecting fillets which are located respectively on either side of the film of material, each of these connecting fillets extending over the entire length of the film of material and having a concave curved shape in the form of a portion of a cylinder which extends angularly over at least 180° around an axis parallel to the film of material; the central block has a general shape elongated along a perpendicular axis in the foreground of symmetry;
[0022] — the central block has in section in said first plane of symmetry a general shape oval or elliptical;
[0023] — the films are elastically deformable, particularly in bending;
[0024] — the films have a thickness less than or equal to 1 mm, preferably less than or equal to 0.5mm, and more preferably less than or equal to 0.2mm;
[0025] — the device has a total length measured along the axis of elongation, which is between 20 and 100 mm, and preferably between 30 and 50 mm;
[0026] — the double gimbal has a total length measured along the axis of elongation, which is between 5 and 50mm, and preferably between 10 and 30mm;
[0027] — the central block is located between two identical pockets formed in the double cardan, each of these pockets separating the central block from one of the intermediate blocks;
[0028] — the volume (of void) of each of the pockets is greater than or equal to the volume (of material) of the central block.
[0029] The invention further relates to an optical or optronic instrument comprising a motor, mobile optical equipment, and a device as described above, the motor comprising a shaft which is coupled to one of the longitudinal ends of the device, the other longitudinal end of which is connected to the optical or optronic equipment for the purpose of its movement. Brief description of the figures
[0030] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:
[0031] [Fig-1] [Fig.l] is a schematic perspective view of a connecting device double cardan mechanics, according to a first embodiment of the invention,
[0032] [Fig.2] [Fig.2] is another schematic perspective view of the device of [Fig.l],
[0033] [Fig.3] [Fig.3] is a schematic sectional view along line III-III of the device of [Fig.l],
[0034] [Fig.4] [Fig.4] is a schematic sectional view along line IV-IV of the device of [Fig.2],
[0035] [Fig.5] [Fig.5] is a schematic perspective view of a double cardan mechanical connection device, according to a second embodiment of the invention,
[0036] [Fig.6] [Fig.6] is another schematic perspective view of the device of [Fig.5],
[0037] [Fig.7] [Fig.7] is a schematic perspective view of the device of [Fig.5] and shows a deformation of the device linked to a misalignment of its longitudinal ends- tudinales,
[0038] [Fig.8] [Fig.8] is a schematic perspective view of the device of [Fig.5] and shows a deformation of the device linked to axial compression,
[0039] [Fig.9] [Fig.9] is another schematic perspective view of the device of [Fig.5] and shows the deformation of the device linked to axial compression,
[0040] [Fig. 10] [Fig. 10] is a schematic perspective view of the device of [Fig.5] and shows a deformation of the device linked to axial traction,
[0041] [Fig. 11] [Fig. 11] is another schematic perspective view of the device of [Fig.5] and shows the deformation of the device linked to axial traction, and
[0042] [Fig. 12] [Fig. 12] is a schematic perspective and sectional view of an optical or optronic instrument comprising a device according to the invention. Detailed description of the invention
[0043] Figures 1 to 4 illustrate a first embodiment of a double cardan mechanical connection device 10.
[0044] This device 10 is particularly suitable, but not exclusively, for use in an optical or optronic instrument such as that illustrated in [Fig. 12].
[0045] The device 10 has a general elongated shape along an elongation axis which is noted X. It has for example a total length measured along the X axis, which is between 20 and 100 mm, and preferably between 30 and 50 mm.
[0046] Essentially, the device 10 comprises three parts, namely:
[0047] - a first longitudinal end 12 of mechanical connection, that is to say capable of be mechanically connected to an element,
[0048] - a second longitudinal end 14 of mechanical connection, that is to say capable of be mechanically connected to another element, and
[0049] - a double cardan 16 between the first and second longitudinal ends 12 and 14.
[0050] In the example shown, the ends 12, 14 have different lengths along the X axis.
[0051] The ends 12, 14 may be of the same type or of different types. In the example shown, they are of the same type.
[0052] Each of the ends 12, 14 may have a generally tubular shape which is threaded and which further comprises axial slots 18 to define angular sections which are elastically deformable in the radial direction. To connect one of these ends 12, 14 to an element, it is sufficient to engage a finger of this element inside the tubular end and then to screw a nut previously mounted on the finger onto the thread of this tubular end. This screwing causes the elastic deformation of the angular sections and their radial tightening on the finger of the element.
[0053] Each of the ends 12, 14 preferably has an external diameter smaller than the external diameter of the double cardan 16. Each of the ends 12, 14 has for example an external diameter less than or equal to 10 mm, preferably less than or equal to 7 mm, and more preferably less than or equal to 5 mm. The double cardan 16 has for example an external diameter between 10 and 30 mm, preferably between 10 and 20 mm, and more preferably between 10 and 15 mm.
[0054] One of the first particularities of the connecting device 10 according to the invention is linked to the fact that the ends 12, 14 are formed in a single piece with the double cardan 16 so that the connecting device 10 is a single piece.
[0055] This connecting device 10 is for example made of a metal alloy, and for example of maraging steel. Due to its relatively complex shape, it can be produced by wire electroerosion or by additive manufacturing.
[0056] Another of the particularities of the device 10 concerns the composition of its double gimbal 16.
[0057] The double gimbal 16 comprises:
[0058] - a first end block 20 which is rigidly connected to the first end lon gitudinal 12,
[0059] - a second end block 22 which is rigidly connected to the second long end tudinal 14,
[0060] - a first intermediate block 24 which is connected to the first end block 20 by a first intermediate film of matter 26,
[0061] - a second intermediate block 28 which is connected to the second end block 22 by a second intermediate film of material 30, and
[0062] - a central block 32 which is located between the first and second intermediate blocks 24, 28 and which is connected to these first and second intermediate blocks 24, 28 respectively by first and second central films of material 33, 34.
[0063] The double gimbal 16 has for example a total length measured along the X axis, which is between 5 and 50 mm, and preferably between 10 and 30 mm.
[0064] The first and second intermediate blocks 24, 28 are disposed between the first and second end blocks 20, 22.
[0065] The first and second intermediate films 26, 30 are located in a first plane PI of the double gimbal 16 which passes through the elongation axis X.
[0066] The first and second central films 33, 34 are located in a second plane P2 of symmetry of the double gimbal 16 which passes through the elongation axis X and which is perpendicular to the first plane of symmetry PL
[0067] Advantageously, the films 26, 30, 33, 34 are elastically deformable, in particular in bending and / or compression and / or traction. These films preferably have a thickness less than or equal to 1 mm, more preferably less than or equal to 0.5mm, and even more preferably less than or equal to 0.2mm.
[0068] In the example shown, the device 10 comprises a third plane P3 of symmetry of the double gimbal 16, which is perpendicular to the elongation axis X and which passes between the first and second intermediate blocks 24, 28 and in the middle of the central block 32.
[0069] As in the example shown, the first and second end blocks 20, 22 may have identical shapes and dimensions, and / or the first and second intermediate blocks 24, 28 may have identical shapes and dimensions.
[0070] The first and second end blocks 20, 22 may have a generally triangular shape in section in the second plane P2, a base B of which is connected to one of the longitudinal ends 12, 14, and a vertex S of which is connected to one of the intermediate films 26, 30.
[0071] The first and second intermediate blocks 24, 28 may each have a general disc or cylinder shape centered on the elongation axis X.
[0072] Each of the end blocks 20, 22 can be separated from the nearest intermediate block 24, 28 by a distance L1 measured along the elongation axis X.
[0073] This distance L1 is preferably less than or equal to 1 mm, preferably less than or equal to 0.5 mm, and more preferably less than or equal to 0.3 mm. This distance L1 may be the smallest on the side of the longitudinal end 12, 14 to which the end block 20, 22 is connected.
[0074] The intermediate blocks 24, 28 are separated from each other by a distance L2 measured along the elongation axis X, which is less than or equal to 1 mm, preferably less than or equal to 0.7 mm, and more preferably less than or equal to 0.5 mm.
[0075] Preferably, the measured distance L1 is the smallest at one of the faces of the aforementioned disc or cylinder, namely at the face located on the side of the end block 20, 22 in the example shown.
[0076] Preferably, the measured distance L2 is the smallest at the level of the faces of the aforementioned disc or cylinder, namely at the level of the faces located on the sides of the central block 32.
[0077] This distance L2 is preferably less than a distance L3 measured along the same axis X between the central block 32 and each of the intermediate blocks 24, 28.
[0078] The first and second intermediate blocks 24, 28 may each have a first recess 40 in which one of the end blocks 20, 22 is at least partially engaged, and a second recess 42 in which the central block 32 is at least partially engaged.
[0079] Preferably, these first and second recesses 40, 42 are located on two opposite faces of the aforementioned disc or cylinder.
[0080] The material films 26, 30, 33, 34 are preferably each connected to the bottom of one recesses 40, 42, by two connecting fillets 44, 46.
[0081] These fillets 44, 46 are located respectively on either side of the film of material 26, 30, 33, 34. Each of these fillets 44, 46 can extend over the entire length of the film of material 26, 30, 33, 34 and preferably has a concave curved shape in the form of a portion of a cylinder which extends angularly over at least 180° around an axis Y parallel to the film of material 26, 30, 33, 34.
[0082] The radius of curvature of each of the fillets 44, 46, around its Y axis, is preferably less than or equal to 1 mm, and more preferably less than or equal to 0.6 mm.
[0083] The central block 32 may have a general elongated shape along an axis Z perpendicular to the first plane of symmetry PI, as in the example shown.
[0084] The central block 32 may have a generally oval or elliptical shape in section in the first plane of symmetry PI.
[0085] The symmetries guarantee rotation without causing unbalance (in rotation) and / or axial fragility.
[0086] The central block 32 is located between two identical pockets 48 formed in the double gimbal 16, each of these pockets 48 separating the central block 32 from the two intermediate blocks 24, 28.
[0087] The volume (of void) of each of the pockets 48 is here very small compared to the volume (of material) of the central block 32.
[0088] Figures 5 and 6 show an alternative embodiment of the device 10 which differs from the previous embodiment by the shape of the intermediate blocks 24, 28. Compared to the previous embodiment, the intermediate blocks 24, 28 are more hollowed out or cut out to reduce their mass.
[0089] In this variant, the volume (of void) of each of the pockets 48 is greater than or equal to the volume (of material) of the central block 32. This makes it possible to vary the axial stiffness of the device 10, without impacting its radial stiffness. It is thus possible to optimize the stiffness of the device 10 by adjusting the volume of the pockets 48.
[0090] Figures 7 to 11 show the elastic deformation capacities of the device 10 which relate to the device 10 of Figures 1 to 4, like that of Figures 5 and 6.
[0091] In [Fig.7], the device 10 undergoes a misalignment, that is to say that the ends 12, 14 of the device are no longer aligned on the same axis, namely the elongation axis X. On the contrary, the ends 12, 14 are aligned respectively on two parallel axes XI, X2. This phenomenon causes an elastic deformation of the double gimbal 16 which is authorized by an elastic deformation of the films 26, 30 and / or the films 33, 34, and which results in a tilting of at least certain blocks relative to the ends 12, 14.
[0092] In figures 8 and 9, the device 10 undergoes an axial force by compression, that is to say that the ends 12, 14 of the device are brought axially towards each other. This phenomenon causes an elastic deformation of the double gimbal 16 which is allowed by an elastic deformation of the films 26, 30 and / or the films 33, 34. This results on the one hand in a bringing together of the end blocks 20, 22 on the intermediate blocks 24, 28, and possibly the axial contact of the end blocks 20, 22 on the intermediate blocks 24, 28 (contacts C1), and / or a bringing together of the intermediate blocks 24, 28 to each other, and possibly the axial contact of these intermediate blocks 24, 28 to each other (contacts C2). These contacts take place on the aforementioned faces.
[0093] In Figures 10 and 11, the device 10 undergoes an axial tensile force, that is to say that the ends 12, 14 of the device 10 are axially spaced apart from each other. This phenomenon causes an elastic deformation of the double cardan 16 which is authorized by an elastic deformation of the films 26, 30 and / or the films 33, 34. This results on the one hand in a spacing of the end blocks 20, 22 with respect to the intermediate blocks 24, 28, and / or a spacing of the intermediate blocks 24, 28 from each other. The aforementioned distances L1 and L2 then increase.
[0094] The present invention also relates to an optical or optronic instrument 50 such as that illustrated in [Fig. 12].
[0095] This instrument 50 comprises a motor 52, a mobile optical equipment 54, and a device 10 as described above.
[0096] The motor 52 here comprises a shaft 56 which is coupled to one of the longitudinal ends 12 of the device 10.
[0097] The other longitudinal end 14 of the device 10 is connected to the optical or optronic equipment 54 for its movement.
[0098] In the example shown, the optical equipment 54 is a lens which is carried by a support 58 which is connected by a barrel 62 to a worm screw 60 coupled to the other longitudinal end 14 of the device 10. The rotational torque of the shaft 56 is transmitted by the device 10 to the worm screw 60 which is driven in rotation and passes through the barrel 62. The barrel 62, for example with balls, transforms the rotation of the worm screw 60 into axial translation. The barrel 62 moves along the worm screw 60 and transmits this movement to the lens via its support 58.
[0099] Although the invention has been described in the context of an optical or optronic application, the double cardan mechanical connection device 10 could be used in another context or field, in particular for any application comprising an element in axial movement (translation) produced by a radial movement (motor).
Claims
Claims
1. Double cardan mechanical connection device (10), this device (10) having a generally elongated shape along an elongation axis (X) and comprising: - a first longitudinal mechanical connection end (12), - a second longitudinal mechanical connection end (14), and - a double cardan (16) between the first and second longitudinal ends (12, 14), characterized in that the first and second ends (12, 14) are formed in one piece with the double cardan (16) so that the connection device (10) is in one piece, and in that the double cardan (16) comprises: - a first end block (20) which is rigidly connected to the first longitudinal end (12), - a second end block (22) which is rigidly connected to the second longitudinal end (14), - a first intermediate block (24) which is connected to the first end block (20) by a first intermediate film of material (26),- a second intermediate block (28) which is connected to the second end block (22) by a second intermediate film of material (30), the first and second intermediate blocks (24, 28) being arranged between the first and second end blocks (20, 22), the first and second intermediate films (26, 30) being located in a first plane (PI) of symmetry of the double gimbal (16) which passes through the elongation axis (X), and - a central block (32) which is located between the first and second intermediate blocks (24, 28) and which is connected to these first and second intermediate blocks (24, 28) respectively by first and second central films of material (33, 34), these first and second central films (33, 34) being located in a second plane (P2) of symmetry of the double gimbal (16) which passes through the elongation axis (X) and which is perpendicular to the first plane of symmetry (FP).,
2. Device (10) according to claim 1, in which it comprises a third plane (P3) of symmetry of the double gimbal (16), which is perpendicular to the axis of elongation (X) and which passes between the first and second intermediate blocks (24, 28) and in the middle of the central block (32).
3. A device (10) according to claim 1 or 2, wherein the first and second end blocks (20, 22) have shapes and dimensions identical, and / or the first and second intermediate blocks (24, 28) have identical shapes and dimensions.
4. Device (10) according to one of the preceding claims, in which the first and second end blocks (20, 22) have in section in said second plane (P2) a generally triangular shape of which a base (B) is connected to one of the longitudinal ends (20, 22), and a vertex (S) is connected to one of the intermediate films (26, 30).
5. Device (10) according to one of the preceding claims, in which the first and second intermediate blocks (24, 28) each have a general shape of a disc or cylinder centered on the axis of elongation (X).
6. Device (10) according to one of the preceding claims, in which each of the end blocks (20, 22) is separated from the nearest intermediate block (24, 28) by a distance (L1) measured along the axis of elongation (X), which is less than or equal to 1 mm, and which is the smallest on the side of the longitudinal end (12, 14) to which the end block (20, 22) is connected.
7. Device (10) according to one of the preceding claims, in which the intermediate blocks (24, 28) are separated from each other by a distance (L2) measured along the elongation axis (X), which is less than or equal to 1 mm.
8. Device (10) according to claim 7, in which the distance (L2) between the intermediate blocks (24, 28) is less than a distance (L3) measured along the elongation axis (X) between the central block (32) and each of the intermediate blocks (24, 28).
9. Device (10) according to one of claims 6 to 8, dependent on claim 5, in which the distance (L1, L2) measured is the smallest at one of the faces of the disc or cylinder, or at the faces of the disc or cylinder.
10. Device (10) according to one of the preceding claims, in which the first and second intermediate blocks (24, 28) each have a first recess (40) in which one of the end blocks (20, 22) is at least partially engaged, and a second recess (42) in which said central block (32) is at least partially engaged.
11. A device (10) according to claim 10, dependent on one of claims 5 or 8, wherein the first and second recesses (40, 42) are located on two opposite faces of the disc or cylinder.
12. Device (10) according to claim 10 or 11, in which the films of material (26, 30, 33, 34) are each connected to the bottom of one of the recesses (40, 42), by two connecting fillets (44, 46) which are located respectively on either side of the film of material (26, 30, 33, 34), each of these connecting fillets (44) extending over the entire length of the film of material (26, 30, 33, 34) and having a concave curved shape in a portion of a cylinder which extends angularly over at least 180° around an axis (Y) parallel to the film of material (26, 30, 33, 34).
13. Device (10) according to one of the preceding claims, in which the central block (32) has a generally elongated shape along an axis (X) perpendicular to the first plane of symmetry (PI).
14. Optical or optronic instrument (50) comprising a motor (52), mobile optical equipment (54), and a device (10) according to one of the preceding claims, the motor (52) comprising a shaft (56) which is coupled to one of the longitudinal ends (12) of the device (10) whose other longitudinal end (14) is connected to the optical or optronic equipment (54) for the purpose of its movement.
Citation Information
Patent Citations
Elongate medical device with articulating portion
US9204783B2
Droplet generator steering system
US9279445B2