Modular gripping unit

Abstract

Gripping unit (1) comprising: a first gripper (10, 110), a second gripper (20, 120) and a third gripper (30, 130); a first connecting rod (40, 60) linking the first gripper (10, 110) and the second gripper (20, 120) and extending in a first direction (D1); a second connecting rod (50, 70) linking the second gripper (20, 120) and the third gripper (30, 130) and extending in a second direction (D2); in which the first connecting rod (40, 60) is arranged to allow a first rotation of the first gripper (10, 110) relative to the second gripper (20, 120) around a first axis of rotation (O10, O110), and the second connecting rod (50, 70) is arranged to allow a second rotation of the third gripper (30, 130) relative to the second gripper (20, 120) around a second axis of rotation (O20, O120). Figure for the abbreviation: Figure 1

Description

Title of the invention: TITLE OF THE INVENTION Modular deformable gripping unit Technical field

[0001] The invention relates to the field of handling and more particularly to the field of multi-gripper gripping units. PREVIOUS STATE OF THE ART

[0002] Gripping units equipped with several grippers, each constituting a controllable point of contact with a workpiece, are known. These grippers are positioned to define an optimal geometry of the connection points to said workpiece. The grippers are fixed to a frame and are controlled individually or in groups to grasp a defined workpiece. These gripping units are very well suited to handling in high-volume production processes. They remain unsuitable for handling varied workpieces and / or small-batch production because changes in the shape of the workpieces require adjusting the relative position of the grippers.

[0003] One solution consists of fixing the grippers on supports that slide relative to each other (generally rails) and reconfiguring the relative positions of the grippers on the supports and of the supports relative to each other. The reconfiguration time of the gripping unit to adapt it to a new geometry of the part to be handled is lengthy and costly and generally requires also reconfiguring the power supply to the grippers (electrical or pneumatic). Thus, such solutions are suitable for medium production runs but do not offer a satisfactory solution for small production runs. PURPOSE OF THE INVENTION

[0004] The invention aims to reduce the time and costs of reconfiguring a gripping unit for switching from one geometry of part to be gripped to another. Description of the invention

[0005] To this end, a gripping unit is provided comprising a first gripper, a second gripper, and a third gripper. A first connecting rod links the first gripper and the second gripper and extends in a first direction. A second connecting rod links the second gripper and the third gripper and extends in a second direction. According to the invention, the first connecting rod is arranged to allow a first rotation of the first gripper relative to the second gripper about a first axis of rotation, and the second connecting rod is arranged to allow a second rotation of the third gripper relative to the second gripper around a second axis of rotation.

[0006] This results in a gripper that can be easily and quickly adapted to various configurations of parts to be gripped without requiring specific tooling or removal of the gripping unit.

[0007] According to other specific, non-exclusive and optional embodiments of the invention: - the first axis of rotation and the second axis of rotation are coincident; - the first axis of rotation is approximately orthogonal to the first direction and / or the second axis of rotation is substantially orthogonal to the second direction; - the first axis of rotation is substantially parallel to the first direction and / or the second axis of rotation is substantially parallel to the second direction; - the second connecting rod is also arranged to allow a third rotation of the third gripper relative to the second gripper around a third axis of rotation distinct from the second axis of rotation; - the third axis of rotation is orthogonal to the second axis of rotation; - the first gripper and / or the second gripper and / or the third The gripper includes a vacuum suction cup; - the first connecting rod and / or the second connecting rod include a fluidic link channel intended to be connected to a vacuum generator; - the gripping unit includes means for locking the first connecting rod in position relative to the second connecting rod; - the locking means include a traction force transmission element which cooperates with the first and second connecting rods to apply a support force from the first connecting rod to the second connecting rod when a traction force is applied to at least one end of the traction force transmission element; - at least one gripper among the first gripper, the second gripper and the third gripper comprises a body extending in a longitudinal direction and the first or second connecting rod comprises a bore for receiving a straight cylindrical portion of at least one gripper, said portion being delimited by a flat intended to receive a clamping force of said connecting rod in the longitudinal direction; - at least one gripper includes a threaded portion to accommodate a clamping nut.

[0008] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention. Brief description of the drawings

[0009] [Fig. 1] [Fig. 1] is a schematic perspective and partial cutaway representation of a gripping unit according to a first embodiment of the invention in a first configuration;

[0010] [Fig.2] [Fig.2] is a schematic cross-sectional representation of a first gripper of the gripping unit of the [Fig.1];

[0011] [Fig.3] [Fig.3] is a schematic cross-sectional representation of a second gripper of the gripping unit of the [Fig.1];

[0012] [Fig.4] [Fig.4] is a schematic cross-sectional representation of a third gripper of the gripping unit of the [Fig.1];

[0013] [Fig.5] [Fig.5] is a schematic representation of a first connecting rod of the gripping unit of the [Fig.1];

[0014] [Fig.6] [Fig.6] is a schematic longitudinal sectional representation of the connecting rod of the [Fig.5];

[0015] [Fig.7] [Fig.7] is a schematic representation of a second connecting rod of the gripping unit of the [Fig.1];

[0016] [Fig.8] [Fig.8] is a schematic longitudinal sectional representation of the connecting rod of the [Fig.7];

[0017] [Fig.9] [Fig.9] is a schematic representation of a power supply ring of the gripping unit of the [Fig.1];

[0018] [Fig. 10] the [Fig. 10] is a schematic representation in longitudinal section of the ring of the [Fig.9];

[0019] [Fig. 11] the [Fig. 11] is a schematic representation of a terminal ring of the gripping unit of the [Fig.1];

[0020] [Fig. 12] [Fig. 12] is a schematic cross-sectional representation of the gripping unit of [Fig. 1] in a second configuration;

[0021] [Fig. 13] [Fig. 13] is a schematic perspective representation of a gripping unit according to a second embodiment of the invention;

[0022] [Fig. 14] [Fig. 14] is a schematic cross-sectional representation of a first gripper of the gripping unit of [Fig. 13];

[0023] [Fig. 15] [Fig. 15] is a schematic cross-sectional representation of a second gripper of the gripping unit of [Fig. 13];

[0024] [Fig. 16] [Fig. 16] is a schematic cross-sectional representation of a third gripper of the gripping unit of [Fig. 13];

[0025] [Fig. 17] [Fig. 17] is a schematic longitudinal sectional representation of a first connecting rod of the gripping unit of [Fig. 13];

[0026] [Fig. 18] [Fig. 18] is a schematic cross-sectional representation of a second connecting rod of the gripping unit of [Fig. 13];

[0027] [Fig. 19] the [Fig. 19] is a schematic representation of a terminal nipple of the grasping unit of the [Fig. 13];

[0028] [Fig.20] [Fig.20] is a partial schematic cross-sectional representation of a unit gripping according to a third embodiment of the invention.

[0029] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0030] With reference to [Fig.1], the gripping unit, generally designated 1, comprises

[0031] a first vacuum gripper 10, a second vacuum gripper 20 and a third vacuum gripper 30.

[0032] A first connecting rod 40 extends along a first direction DI to connect the gripper 10 and the gripper 20. A second connecting rod 50 extends along a second direction D2 to connect the gripper 20 and the gripper 30.

[0033] According to this first embodiment, the grippers 10, 20 and 30 are all identical and only gripper 10 will be described in detail.

[0034] With reference to [Fig. 2], the gripper 10 comprises a first body 11 extending along a first longitudinal direction D10. The body 11 comprises, at its first proximal end 11.1, a first TH-type head 12 from which extends a first straight cylindrical portion 13. The underside of the head 12 defines a first flat 12.1 which delimits the portion 13. A first threaded portion 14 connects the portion 13 and a first tip 15 located at the first distal end 11.2 of the body 11. The tip 15 is smooth and receives a first vacuum suction cup 16. The body 11 comprises a first axial blind internal bore 17 which extends along the direction D10 and opens at the distal end 11.2 into a first internal chamber 16.1 of the suction cup 16.

[0035] Portion 13 includes a first upper circumferential groove 13.1 in fluidic communication with the bore 17 via a first upper radial channel 13.10 and a first lower circumferential groove 13.2 in fluidic communication with the bore 17 via a first lower radial channel 13.20. Portion 13 also includes three first upper circumferential grooves 13.3, middle 13.4 and lower 13.5 for receiving respectively a first upper O-ring seal 13.30, a second middle O-ring seal 13.40 and a first lower O-ring seal 13.50.

[0036] Similarly, the gripper 20 includes a second body 21 extending along a second longitudinal direction D20 which includes, at its second proximal end 21.1, a second head 22 which defines a second flat 22.1. A second threaded portion 24 connects the second straight cylindrical portion 23 and a second end piece 25 located at the second distal end 21.2 of the body 21. The end piece 25 is smooth and receives a second suction cup 26 whose second internal chamber 26.1 is fluidically connected to the second internal bore 27. The portion 23 includes two second grooves, upper 23.1 and lower 23.2, in fluidic communication with the bore 27 via second channels, upper 23.10 and lower 23.20, as well as three second grooves 23.3, 23.4 and 23.5 for receiving O-rings 23.30, 23.40 and 23.50.

[0037] Similarly, the gripper 30 includes a third body 31 extending along a third longitudinal direction D30 which includes, at its third proximal end 31.1, a third head 32 which defines a third flat 32.1. A third threaded portion 34 connects the third straight cylindrical portion 33 and a third end piece 35 located at the third distal end 31.2 of the body 31.The tip 35 is smooth and receives a third suction cup 36 whose third internal chamber 36.1 is fluidically connected to the third internal bore 37. The portion 33 includes two upper third grooves 33.1 and lower third grooves 33.2 in fluidic communication with the bore 37 via upper third channels 33.10 and lower third channels 33.20 as well as three upper third grooves 33.3, middle third groove 33.4 and lower third groove 33.5 for receiving the O-rings 33.30, 33.40 and 33.50.

[0038] According to this first embodiment, the connecting rods 40 and 50 are all identical and only the connecting rod 40 will be described in detail.

[0039] With reference to Figures 5 and 6, the connecting rod 40 comprises a first portion 40.1 and a second portion 40.2 in the form of a straight cylinder and which are connected by a central portion 40.3 which is tangent to portions 40.1 and 40.2. Portion 40.1 comprises a first bore 41 and portion 40.2 comprises a second bore 42. A second channel 43 fluidly connects bores 41 and 42.

[0040] Similarly, the connecting rod 50 comprises a third portion 50.1 provided with a third bore 51 and a fourth portion 50.2 provided with a fourth bore 52. A third channel 53 fluidly connects the bores 51 and 52 (figures 7 and 8).

[0041] Unit 1 also includes a straight cylindrical feed ring 2 which includes a central feed bore 3 connected by a fourth radial channel 4 to a vacuum generator 5 (Figures 9 and 10).

[0042] Unit 1 also includes a straight cylindrical terminal ring 6 which includes a central terminal bore 7 ([Fig. 11]).

[0043] With reference to Figures 1 and 2, unit 1 is obtained by mounting the ring 2 and the bore 41 of the connecting rod 40 onto the gripper 10 such that the channel 4 is in fluidic communication with the groove 13.1 and such that the channel 43 is in fluidic communication with the groove 13.2. The seals 13.30, 13.40 and 13.50 ensure the sealing of the fluidic connections of the channel 4 with the groove 13.1 and of the channel 43 with the groove 13.2. A nut 18 is engaged and tightened on the threaded portion 14. The nut 18 exerts a clamping force in the direction D10 of the portion 40.1 between the nut 18 and the flat 12.1 via the ring 2.

[0044] The connecting rod 50 is then placed in contact with the connecting rod 40 so that the bores 42 and 51 are aligned. The gripper 20 is engaged through the bores 42 and 51 so that the channel 53 is in fluidic communication with the groove 23.1 and so that the channel 43 is in fluidic communication with the groove 23.2. The seals 23.30, 23.40 and 23.50 ensure the sealing of the fluidic connections of the channel 53 with the groove 23.1 and of the channel 43 with the groove 23.2. A nut 28 is engaged and tightened on the threaded portion 24. The nut 28 exerts a clamping force along the direction D20 of the portion 40.2 between the nut 28 and the flat 22.1 via the portion 50.1.

[0045] The ring 6 is then placed in contact with the connecting rod 50 so that the bores 7 and 52 are aligned. The gripper 30 is engaged through the bores 7 and 52 so that the channel 53 is in fluidic communication with the groove 33.1 and so that the groove 33.2 is closed by the ring 6. The seals 33.30, 33.40 and 33.50 ensure the sealing of the fluidic connections of the channel 53 with the groove 33.1 and the closure of the groove 33.2. A nut 38 is engaged and tightened onto the threaded portion 34. The nut 38 exerts a clamping force along the direction D30 of the ring 6 between the nut 38 and the flat 32.1 via the portion 50.2.

[0046] Tightening the nut 28 and adjusting the bores 42 and 51 allows a first rotation of the gripper 10 relative to the gripper 20 around a first axis of rotation 010 coinciding with the direction D20, and a second rotation of the gripper 30 relative to the gripper 20 around a second axis of rotation 020 coinciding with the direction D20. According to this first embodiment, the first axis of rotation 010 and the second axis of rotation 020 coincide, and the first axis of rotation 010 is substantially orthogonal to the direction DI and the second axis of rotation 020 is substantially orthogonal to the direction D2.

[0047] The rings 2 and 6 as well as the channels 43 and 53 and their connections with the grooves 13.1, 13.2, 23.1, 23.2, 33.1 and 33.2 make a pneumatic circuit 8 supplying the grippers 10, 20 and 30 in vacuum connected by the channel 4 to the generator 5.

[0048] A unit 1 is thus obtained in the form of a "chain" whose links are made up of the connecting rods 40 and 50 articulated on the grippers 10, 20 and 30.

[0049] In operation, a first configuration of unit 1, corresponding to a first relative position of the grippers 10, 20, and 30, is defined by manual action of an operator on the grippers 10, 20, and 30. Here, the first configuration is an alignment configuration of the grippers 10, 20, and 30 shown in [Fig. 12]. The mounting clearances of the bores 42 and 51 on the portion 13, as well as the tightening of the nut 28 and the friction of the seals 23.20, 23.30, and 23.40 on the bores 42 and 51 These allow for manual movement of the grippers 10, 20, and 30 relative to each other, as well as maintaining their position during gripping operations. Thus, the nuts 18, 28, and 38 act as locking mechanisms for the connecting rod 40 relative to the connecting rod 50.

[0050] Unit 1 is then, in this first configuration, able to perform the selective grasping and release of elongated objects by controlling the vacuum generator 5.

[0051] When it is desired that unit 1 be able to grasp parts of different shapes, a shape with a circular cross-section for example, the operator manipulates gripper 10 so as to apply a rotational movement to it around axis 020 relative to gripper 20. The operator does the same with gripper 30 and manipulates it so as to apply a rotational movement to it around axis 020 relative to gripper 20 and obtain a second configuration of unit 1 in which grippers 10, 20 and 30 form the vertices of an isosceles triangle, represented in [Fig. 1].

[0052] Unit 1 is then, in this second configuration, able to perform the selective gripping and release of objects with a circular cross-section by controlling the vacuum generator 5.

[0053] Elements identical or analogous to those previously described shall bear a numerical reference identical to that in the following description of a second embodiment of the invention.

[0054] According to a second embodiment represented in [Fig. 13], a third connecting rod 60 extends along the DI direction to connect a fourth gripper 110 and a fifth gripper 120 and a fourth connecting rod 70 extends along the D2 direction to connect the gripper 120 and a sixth gripper 130.

[0055] With reference to [Fig. 14], the gripper 110 comprises a fourth body 111 extending along a fourth longitudinal direction DUO. The body 111 includes a fifth threaded portion 112 extending between the fourth proximal end 111.1 of the body 111 and a fifth straight cylindrical portion 113. The portion 113 connects the threaded portion 112 to an upper face 114.1 of a fourth substantially parallelepiped-shaped block 114 of the body 111. A fifth bore 115 extends between two fourth faces 114.3 and 114.4 of the block 114 in a direction substantially orthogonal to the DI direction 10. The faces 114.3 and 114.4 define fourth flats of the gripper 110. A fourth tip 116 extends from an inferior face 114.2 of the block 114 opposite face 114.1 to the fourth distal end 111.2 of the body 111. Tip 116 is smooth and receives a fourth suction cup 117 for vacuum gripping.The body 111 includes a fourth internal through bore 118 axial which extends along the DI 10 direction and opens into . the distal end 111.2 of the body 111 in a fourth internal enclosure 117.1 of the suction cup 117. A first cap 118.1 comes to close the end of the drilling 118 located at the proximal end 111.1 of the body 111.

[0056] A fifth radial channel 113.10 connects the bore 118 with an outer surface 113.1 of the portion 113. The portion 113 also includes a fourth upper circumferential groove 113.2 and a fourth lower circumferential groove 113.3 for receiving respectively a fourth upper sealing toroid 113.20 and a fourth lower sealing toroid 113.30.

[0057] With reference to [Fig. 15], the gripper 120 comprises a fifth body 121 extending along a fifth longitudinal direction DI20 and which comprises a fifth block 122 through which a sixth bore 113 extends between two fifth faces 122.1 and 122.2 of the block 122 in a direction substantially orthogonal to the direction D120. The faces 112.1 and 112.2 define fifth flats of the gripper 120.

[0058] The gripper 120 includes a sixth cylindrical portion 124 extending from a fifth lower face 122.3 of the block 122 to connect the block 122 to a sixth threaded portion 125, at the end of which is a fifth tip 126 located at the fifth distal end 121.2 of the body 121. The tip 126 is smooth and receives a fifth vacuum suction cup 127. The body 121 includes a fifth axial through-hole 128 extending along the direction D120 and opening at the distal end 121.2 of the body 121 into a fifth internal chamber 127.1 of the suction cup 127. A second cap 128.1 closes the end of the hole 128 located at the proximal end 121.1 of the body 121.

[0059] A sixth radial channel 124.10 connects the bore 128 with an outer surface 124.1 of the portion 124. The portion 124 also includes a fifth circumferential upper groove 124.2 and lower groove 124.3 for receiving respectively a fourth upper sealing toroidal seal 124.20 and a fourth lower sealing toroidal seal 124.30.

[0060] The gripper 130 is similar to the gripper 110 and comprises a sixth body 131 extending along a sixth longitudinal direction D130. The body 131 includes a seventh threaded portion 132 extending between the sixth proximal end 131.1 of the body 131 and a seventh straight cylindrical portion 133. The portion 133 connects the threaded portion 132 to an upper face 134.1 of a sixth substantially parallelepiped-shaped block 134 of the body 131. A seventh bore 135 extends between two sixth faces 134.3 and 134.4 of the block 134 in a direction substantially orthogonal to the direction D130. Faces 134.3 and 134.4 define sixth flats of the gripper 130. A sixth tip 136 extends from a lower face 134.2 of the block 134 opposite face 134.1 to the fourth distal end 131.2 of the body 131. The tip 136 is smooth and receives a sixth suction cup 137 for vacuum gripping. The body 131 includes a sixth internal bore 138 axially extending in the direction D130 and opening at the distal end 131.2 of the body 131 into a fourth internal chamber 137.1 of the suction cup 137. A first cap 138.1 closes the end of the bore 138 located at the proximal end 131.1 of the body 131.

[0061] A seventh radial channel 133.10 connects the bore 138 with an outer surface 133.1 of the portion 133. The portion 133 also includes a sixth upper circumferential groove 133.2 and a sixth lower circumferential groove 133.3 for receiving respectively a sixth upper sealing toroidal seal 133.20 and a sixth lower sealing toroidal seal 133.30.

[0062] According to this second embodiment, the connecting rods 60 and 70 are all identical and only the connecting rod 60 will be described in detail.

[0063] With reference to figures 17 and 18, the connecting rod 60 is parallelepiped in shape and comprises an eighth portion 60.1 and a ninth portion 60.2. The portion 60.1 comprises a seventh bore 61 and the portion 60.2 comprises an eleventh straight cylindrical portion 62 terminated by a seventh threaded end 60.3. An eighth channel 63 extends in the body of the connecting rod 60 in the direction DI and opens into a seventh circumferential groove 61.1 of the bore 61. A seventh radial channel 62.10 connects the channel 63 to a seventh circumferential groove 62.1 of the portion 62. The portion 62 also includes an eighth proximal circumferential groove 62.2 and an eighth distal circumferential groove 62.3 which respectively accommodate a seventh proximal sealing toric joint 64.20 and a seventh distal sealing toric joint 64.30.

[0064] As seen in [Fig.17], the channel 63 opens into the end of the portion 60.1 of the connecting rod 70 and receives a fourth obturating cap 63.1.

[0065] Similarly, the connecting rod 70 comprises a twelfth portion 70.1 provided with an eighth bore 71 and a thirteenth portion 70.2 provided with a fourteenth straight cylindrical portion 72 terminated by an eighth threaded end 70.3. A ninth channel 73 extends in the body of the connecting rod 70 in the direction D2 and opens into an eighth circumferential groove 71.1 of the bore 71. An eighth radial channel 72.10 connects the channel 73 to a ninth circumferential groove 72.1 of the portion 72. The portion 72 also includes a tenth proximal circumferential groove 72.2 and a tenth distal circumferential groove 72.3 which respectively accommodate an eighth proximal sealing toric joint 74.20 and an eighth distal sealing toric joint 74.30.

[0066] As seen in [Fig.18], the channel 73 opens into the end of the portion 70.1 of the connecting rod 70 and receives a fifth obturating cap 73.1.

[0067] Unit 1 also includes a straight cylindrical feed ring 102 which includes a central feed bore 103 and a circumferential feed groove 103.1 connected by a ninth radial channel 104 to a vacuum generator 5 ([Fig. 19]).

[0068] Unit 1 also includes a straight cylindrical terminal nipple 106 which comprises a support portion 107, a median portion 108 and an eighth threaded portion 109 ([Fig.20]). The portion 108 includes a diametral channel 108.1 as well as an eleventh proximal circumferential groove 108.2 and an eleventh distal circumferential groove 108.3 for receiving respectively a ninth proximal sealing toric seal 108.20 and an eighth distal sealing toric seal 108.30.

[0069] With reference to [Fig. 21], unit 1 is obtained by mounting ring 102 on portion 113 of gripper 110 and tightening it against face 114.1 using a nut 119.1 engaged on portion 112. Portion 62 of connecting rod 60 is then engaged in bore 115 of gripper 110 so that bore 118 of gripper 110 is in fluidic communication with groove 62.1 of connecting rod 60. Seals 62.20 and 62.30 ensure the sealing of the fluidic connection of bore 118 with groove 62.1. The seals 113.20 and 113.30 ensure the sealing of the fluidic link of the bore 118 via the channel 113.10 with the channel 104 and the vacuum generator 5. A nut 119.2 is engaged and tightened on the threaded end 60.3 to hold the gripper 110 on the connecting rod 60.

[0070] Portion 124 of the gripper 120 is then engaged in the bore 61 of the connecting rod 60 so that the bore 128 of the gripper 120 is in fluidic communication with the groove 61.1 of the connecting rod 60. Seals 124.20 and 124.30 ensure the sealing of the fluidic connection of the bore 128 with the groove 61.1. A nut 129.1 is engaged and tightened onto the threaded portion 125 to secure the gripper 110 to the connecting rod 60. The suction cup 127 is then installed on the end piece 126.

[0071] The portion 72 of the connecting rod 70 is then engaged in the bore 123 of the gripper 120 so that the bore 128 of the gripper 120 is in fluidic communication with the groove 62.1 of the connecting rod 60. The seals 62.20 and 62.30 ensure the sealing of the fluidic connection of the bore 128 with the groove 62.1. A nut 129.2 is engaged and tightened on the threaded end 70.3 to hold the gripper 120 on the connecting rod 70.

[0072] Portion 133 of the gripper 130 is then engaged in the bore 71 of the connecting rod 70 so that the bore 138 of the gripper 130 is in fluidic communication with the groove 71.1 of the connecting rod 70. Seals 134.20 and 134.30 ensure the sealing of the fluidic connection of the bore 138 with the groove 71.1. A nut 139.1 is engaged and tightened onto the threaded portion 132 to retain the gripper 130 on connecting rod 70. Suction cup 127 is then installed on tip 126.

[0073] The nipple 106 is then engaged in the bore 135 of the gripper 130. The portion 107 bears against the face 134.4 and the middle portion 108 extends into the bore 135 so that the channel 108.1 is in line with the bore 138. A nut 139.2 is engaged and tightened onto the portion 109. The seals 108.20 and 108.30 ensure the sealing of the connection between the channel 108.1 and the bore 138.

[0074] Tightening the nut 129.1 and adjusting the bores 61 and 123 allows a first rotation of the gripper 110 relative to the gripper 120 around a first axis of rotation 0110 coinciding with the direction D120, and a second rotation of the gripper 130 relative to the gripper 120 around a second axis of rotation 0120 coinciding with the direction D120. The first axis of rotation 0110 and the second axis of rotation 0120 coincide, and the first axis of rotation 0110 is substantially orthogonal to the direction DI and the second axis of rotation 0120 is substantially orthogonal to the direction D2.

[0075] Tightening the nuts 119.2 and 129.2, as well as adjusting the bores 115 and 123, allows a third rotation of the gripper 110 relative to the gripper 20 about a third axis of rotation 0110' coinciding with the direction DI, and a fourth rotation of the gripper 130 relative to the gripper 20 about a fourth axis of rotation 0120' coinciding with the direction D2. The third axis of rotation 0110' is substantially parallel to the direction DI, and the fourth axis of rotation 0120' is substantially parallel to the direction D2. The third axis of rotation 0110' is orthogonal to the first axis of rotation 0110 and to the second axis of rotation 0120.

[0076] The ring 102, the nipple 106 as well as the bores and channels 108.1, 118, 128, 138, 63 and 73 and their connections with the grooves 61.1, 62.1, 71.1, 72.1 form a pneumatic circuit 8 for supplying the grippers 110, 120 and 130 in vacuum connected by the channel 4 to the generator 5.

[0077] The operation of unit 1 according to this second embodiment is similar to the operation of the gripping unit according to the first embodiment. This second embodiment allows, in addition to the advantages associated with the first embodiment, the gripping of parts with complex three-dimensional shapes.

[0078] According to a third embodiment shown in [Fig. 21], unit 1 comprises a terminal half-connecting rod 80 integral with the gripper 30. The grippers 10, 20, and 30 have bores 210, 220, and 230, respectively, which pass diametrically through the bodies 11, 21, and 31. The connecting rods 40 and 50 have longitudinal bores 240 and 250, respectively. The half-connecting rod 80 has a longitudinal bore 280. The bores 210, 220, 230, 240, 250, and 280 are aligned and are traversed by a cable 260. A crimp 261 disposed on a distal end 262 of the cable 260 bears against a distal face 81 of the half-connecting rod 80. The proximal end 263 of the cable 260 is connected to a winch 270. The connecting rods 40 and 50 as well as the half-connecting rod 80 have, here, a clevis-shaped end with two ears.

[0079] The operation of unit 1 according to this third embodiment is similar to the operation of the gripping unit according to the first and second embodiments. This third embodiment allows, in addition to the advantages associated with the first and second embodiments, for the first connecting rod 40 to be locked in position relative to the second connecting rod 50 by actuating the winch 270. Indeed, when the winch 270 exerts a tensile force on the cable 260, the cable 260 exerts a bearing force on the connecting rod 40 on the connecting rod 50 via the half-connecting rod 80, which locks the position of the connecting rod 40 relative to the connecting rod 50.

[0080] It is thus possible to choose adjustments of the connecting rods 40 and 50 on the grippers 10, 20 and 30 which allow free relative movements of the grippers 10, 20 and 30 between them and, once they have adopted a position which seems suitable, to lock this position by acting on the winch 270.

[0081] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0082] In particular, - although here the connecting rods are all identical, the invention also applies to different connecting rods such as, for example, connecting rods of different lengths or of which a portion incorporates the feed ring or the terminal ring or the terminal stud; - although here the connecting rods include internal channels which together with the grooves of the grippers form a pneumatic vacuum supply circuit, the invention also applies to a gripping unit in which the pneumatic circuit is located away from the connecting rods; - although here the relative positioning of the grippers is done manually by an operator, the invention also applies to a gripping unit in which the connecting rods are arranged so that the grippers are freely mobile relative to each other and their relative positions are fixed when the pneumatic circuit is evacuated; - although here the grippers are of the vacuum suction cup type, the invention also applies to other types of grippers such as, for example, clamp grippers or electromagnetic type grippers; Although here the connecting rods are crossed by a cable, the invention also applies to other types of transmission element for a tensile force such as for example a chain or a belt or a prestressed element of elastic type, the transmission element for a tensile force can also be arranged in a path integral with the connecting rods and located outside of them; Although here the means for locking the relative position of the connecting rods include nuts or a cable, the invention also applies to other types of means for locking the position of the first connecting rod relative to the second connecting rod, such as an electromagnet, a controllable wheel / ratchet assembly, braked toothed wheels; Although here the gripping unit comprises three grippers mounted in series, the invention also applies to a gripping unit comprising more than three grippers connected in series by connecting rods as well as other gripper configurations such as for example a star configuration in which the second gripper would be at the center of the star.

Claims

Claims

1. Gripping unit (1) comprising: - a first gripper (10, 110), a second gripper (20, 120) and a third gripper (30, 130); - a first connecting rod (40, 60) connecting the first gripper (10, 110) and the second gripper (20, 120) and which extends in a first direction (Dl), the first gripper (10, 110) being located at a first end point (41, 61) of the first connecting rod (10, 110) and the second gripper (20, 120) being located at a second end point (42, 62) of the first connecting rod (10, 110); - a second connecting rod (50, 70) connecting the second gripper (20, 120) and the third gripper (30, 130) and which extends in a second direction (D2), the second gripper (20, 120) being located at a first termination point (51, 71) of the second connecting rod (20, 120) and the third gripper (30, 130) being located at a second termination point (52, 72) of the second connecting rod (50, 70);wherein, the first link (40, 60) is arranged to allow a first rotation of the first gripper (10, 110) relative to the second gripper (20, 120) around a first axis of rotation (010, 0110) passing through the first termination point (41, 61) of the first link (40, 60), and the second link (50, 70) is arranged to allow a second rotation of the third gripper (30, 130) relative to the second gripper (20, 120) around a second axis of rotation (020, 0120) passing through the second termination point (42, 62) of the first link (40, 60) and the first termination point (51, 71) of the second link (50, 70).;

2. Gripping unit (1) according to claim 1, wherein the first axis of rotation (010, 0110) and the second axis of rotation (020, 0120) are coincident.

3. Gripping unit (1) according to claim 1, wherein the first axis of rotation (010, 0110) is substantially orthogonal to the first direction (Dl) and / or the second axis of rotation (020, 0120) is substantially orthogonal to the second direction (D2).

4. Gripping unit (1) according to claim 1, wherein the first axis of rotation (010, 0110) is substantially parallel to the first direction (D1) and / or the second axis of rotation (020, 0120) is substantially parallel to the second direction (D2).

5. Gripping unit (1) according to any one of the preceding claims, in which the second link (50, 70) is also arranged to allow a third rotation of the third gripper (30, 130) relative to the second gripper (20, 120) around a third axis of rotation (0110') distinct from the second axis of rotation (0120).

6. Gripping unit (1) according to claim 5, wherein the third axis of rotation (0110') is orthogonal to the second axis of rotation (0120).

7. Gripping unit (1) according to any one of the preceding claims, wherein the first gripper (10, 110) and / or the second gripper (20, 120) and / or the third gripper (30, 130) comprises a vacuum gripping suction cup (17, 27, 37, 117, 127, 137).

8. Gripping unit (1) according to claim 7, wherein the first link (40, 60) and / or the second link (50, 70) comprise a fluid connection channel (43, 53, 63, 73) intended to be connected to a vacuum generator (5).

9. Gripping unit (l) according to any one of the preceding claims, comprising locking means (18, 28, 38, 119.1, 119.2, 129.1, 129.2, 139.1, 139.2, 260) in position of the first link (40, 60) relative to the second link (50, 70).

10. Gripping unit (1) according to claim 9, wherein the locking means (18, 28, 38, 119.1, 119.2, 129.1, 129.2, 139.1, 139.2, 260) comprise a tensile force transmission element (260) which cooperates with the first link (40, 60) and the second link (50, 70) to apply a bearing force of the first link (40, 60) on the second link (50, 70) when applying a tensile force to at least one end (263) of the tensile force transmission element (260).

11. A gripping unit (1) according to any preceding claim, wherein at least one gripper among the first gripper (10, 110), the second gripper (20, 120) and the third gripper (30, 130) comprises a body (11, 21, 31, 111, 121, 131) extending in a longitudinal direction (D10, D20, D30, DI 10, D120, DI30) and the first link (40, 60) or the second link (20, 120) comprises a bore (41, 42, 51, 52, 61, 71) for receiving a straight cylindrical portion (13, 23, 33, 113, 124, 133) of the at least one gripper (10, 20, 30, 110, 120, 130), said portion (13, 23, 33, 113, 124, 133) being delimited by a flat intended to receive a tightening force from said connecting rod (40, 50, 60, 70) in the longitudinal direction (D10, D20, D30, DUO, D120, D130).

12. Gripping unit (1) according to claim 11, wherein the at least one gripper (10, 20, 30, 110, 120, 130) comprises a threaded portion (14, 24, 34, 112, 125, 132) for receiving a clamping nut (18, 28, 38, 119.1, 119.2, 129.1, 129.2, 139.1, 139.2).

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