electromagnetic clamp

Abstract

A clamp mechanism comprises a stator (2) and a pair of movable clamps movably coupled to the stator (2) via linear bearings (8), the stator (2) comprising a housing (4) and a permanent magnet (3) mounted within the housing (4), the movable clamp (19) comprising a support (9), a coil (11) mounted on the support (9) and a clamp finger (10) coupled to the support (9), the coil (11) being configured to generate a magnetic field opposite to the magnetic field of the permanent magnet (3) to actuate the movable clamp to shift relative to the stator. The clamp mechanism further comprises at least one magnetic locking mechanism (7), the magnetic locking mechanism (7) comprising at least a first permanent magnet (18) mounted on one of the stator (2) and the movable clamp (19), and a complementary soft magnetic material portion or magnet mounted on the other of the stator (2) and the movable clamp (19), the magnetic locking mechanism being configured to magnetically lock the movable clamp in at least one of a closed position or an open position of the movable clamp (19).

Description

Technical Field

[0001] The present invention relates to a clamping mechanism for mounting on a machine to clamp and release a component. The clamping mechanism can be mounted on a robot arm or other mobile platform for picking up and placing objects, for example for assembly of components. Background Art

[0002] Gripper mechanisms are widely used in automated manufacturing processes for component assembly and are typically mounted on mobile robotic arms or on moving stages or slides for picking and placing components. Both pneumatically and electromagnetically operated gripper mechanisms are known. In many applications, a compact and lightweight gripper mechanism is required to allow for high acceleration and deceleration of the movable machine element carrying the gripper. Given the high cost of machine downtime in the manufacturing process, the reliability and durability of the gripper mechanism are also important. Ease of installation and maintenance are also important factors in ensuring low costs. The performance of the gripper mechanism, particularly its actuation speed, is also important, and the demand for reduced energy consumption is increasing.

[0003] Many gripping mechanisms are based on pneumatic actuation, but these often lack flexibility, especially when changes are needed during the manufacturing process, such as adjustments to different parts. Electromagnetic gripping systems are often more convenient in this regard, but conventional electromagnetic gripping mechanisms fall short of the required requirements, particularly a combination of light weight, compactness, reliability, ease of control and maintenance, and low energy consumption. One drawback of many electromagnetic gripping systems is that the gripper motors heat up during operation, requiring cooling systems for high-performance applications. Summary of the Invention

[0004] In view of the above, an object of the present invention is to provide a clamping mechanism that is reliable, has a fast actuation speed, and has low energy consumption.

[0005] It would be advantageous to provide a clamp mechanism that is lightweight and compact.

[0006] It would be advantageous to provide a clamp mechanism that is easily controlled.

[0007] It would be advantageous to provide a clamp mechanism that is easy to install and maintain.

[0008] The object of the present invention has been achieved by providing the clamp mechanism described above.The embodiments of the present invention describe various advantageous features of the present invention.

[0009] Disclosed herein is a clamp mechanism comprising a stator and a pair of movable clamps movably coupled to the stator via linear bearings. The stator comprises a housing and a permanent magnet mounted within the housing. The movable clamp comprises a support portion, a coil mounted on the support portion, and a clamp finger coupled to the support portion. The coil is configured to generate a magnetic field opposite to the magnetic field of the permanent magnet to actuate the movable clamp to shift relative to the stator. The clamp mechanism further comprises at least one magnetic locking mechanism comprising at least a first permanent magnet block mounted on one of the stator and the movable clamp, and a complementary soft magnetic material portion or magnet mounted on the other of the stator and the movable clamp, the magnetic locking mechanism being configured to magnetically lock the movable clamp in at least one of a closed position or an open position of the movable clamp.

[0010] In an advantageous embodiment, the magnetic locking mechanism comprises at least a second permanent magnet, which is arranged such that the movable clamp is held in the open position and in the closed position by magnetic force.

[0011] In an advantageous embodiment, the movable clamp and the stator comprise spacer elements at abutting locations between the movable clamp and the stator in the open and / or closed position, the spacer elements being configured to maintain a magnetic field gap between the first permanent magnet block and the complementary soft magnetic material portion or magnet.

[0012] In an advantageous embodiment, the at least one permanent magnet of the magnetic locking mechanism is positioned substantially centrally between the movable clamps in the translation direction of the movable clamps.

[0013] In an advantageous embodiment, the movable fixture comprises a ferromagnetic portion complementary to a permanent magnet block mounted on the stator housing.

[0014] In an advantageous embodiment, at least one of said permanent magnet blocks is mounted on one of the stator housing exterior and one end of the movable fixture, and at least one of said complementary soft magnetic material portions or magnets is mounted on the other of the stator housing exterior and this end of the movable fixture.

[0015] In an advantageous embodiment, the permanent magnet is substantially flat in shape and has a thickness substantially smaller than its length or height seen in a plane parallel to the displacement direction of the movable fixture, the thickness being measured in a direction orthogonal to said plane parallel to the displacement direction.

[0016] In an advantageous embodiment, the permanent magnet is substantially flat and substantially rectangular in shape.

[0017] In an advantageous embodiment, the stator comprises a magnetic circuit armature comprising armature outer portions of soft magnetic material mounted on opposite outer sides of the housing so that an air gap is formed between the armature outer portion and the permanent magnets, in which the coils of the movable fixture are positioned and displaced.

[0018] In an advantageous embodiment, the armature exterior has a surface area which is oriented towards the permanent magnets and which is substantially the same size or larger.

[0019] In an advantageous embodiment, the armature outer portion is a substantially flat and thin portion.

[0020] In an advantageous embodiment, the permanent magnet is centrally positioned between the coils of a pair of movable clamps, with the N-S poles of the permanent magnet being arranged in a direction substantially parallel to the translation direction of the movable clamps.

[0021] In an advantageous embodiment, the length of the coil of each movable fixture in the translation direction of the movable fixture is smaller than the length of the permanent magnet in the translation direction of the movable fixture, preferably 70% smaller, more preferably 60% smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Further objects and advantageous features of the present invention will become apparent from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, in which:

[0023] Figure 1a is a perspective view of a clamp mechanism according to an embodiment of the present invention;

[0024] Figure 1b is a cross-sectional perspective view of a clamp mechanism according to an embodiment of the present invention;

[0025] Figure 2 is an exploded perspective view of a clamp mechanism according to an embodiment of the present invention;

[0026] Figure 3a and 3b is a partially exploded perspective view of a clamp mechanism according to an embodiment of the present invention, shown in an open position and a closed position;

[0027] Figure 4a is a perspective view of a clamp mechanism according to an embodiment of the present invention, wherein the housing portion is disassembled;

[0028] Figure 4b is a perspective view of a clamp mechanism according to an embodiment of the present invention, wherein the housing portion and the movable clamp on one side are disassembled;

[0029] Figure 4c is a perspective view of a movable clamp of a clamp mechanism according to an embodiment of the present invention;

[0030] Figure 5a and 5b is a simplified schematic diagram of a locking mechanism of a clamp mechanism according to an embodiment of the present invention;

[0031] Figure 6 is a perspective view of a locking mechanism of a clamp mechanism according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] With reference to the accompanying drawings, a clamping mechanism 1 according to an embodiment of the present invention comprises a stator 2 and a pair of movable clamps 19 movably mounted on the stator 2 via bearings 8. The bearings 8 are arranged to guide the movable clamps 19 in a translation direction D relative to the stator 2. In an advantageous embodiment, the bearings 8 may be in the form of linear ball bearings or roller bearings. However, in other embodiments, the bearings may be lubricated plain bearings or plain bearings comprising a low-friction material. The term "bearing" means one or more bearings which may be arranged closely together or in a spaced relationship, depending on the size of the clamping mechanism and the required clamping force, since the greater the clamping force, the larger the clamping mechanism should generally be.

[0033] The stator 2 comprises a permanent magnet 3 arranged between a pair of movable clamps 19. The permanent magnet 3 forms a common stator component for both clamps. The movable clamps 19 move linearly in opposite directions between an open position and a closed position.

[0034] The permanent magnet 3 can advantageously be in the form of a substantially flat plate, such as a rectangular plate, with a thickness W substantially less than the length L1 or height H1 of the plate shape, the thickness W being viewed in a direction T perpendicular to the translation (or movement) direction D of the movable fixture 19 relative to the stator 2. The permanent magnet 3 has a pair of N-s poles that generate a magnetic flux perpendicular to the translation (or movement) direction D of the movable fixture. Therefore, the permanent magnet 3 is disposed substantially centrally between the movable fixtures 19, with the main plane of the permanent magnet 3 substantially parallel to the translation (or movement) direction D of the movable fixture.

[0035] Stator 2 includes a housing 4 having a central portion 4b that supports permanent magnet 3 and outer portions 4a located on either side of central portion 4b, surrounding a movable fixture 19. A support frame portion 16 of central portion 4b mechanically supports permanent magnet 3. Housing 4 further includes a bearing portion 17 for supporting the stationary portion (fixed portion) 8a of bearing 8. Central portion 4b and outer portion 4a of the housing can be made of non-magnetic material.

[0036] The stator 2 further includes a magnetic circuit armature 5 made of a ferromagnetic or soft magnetic material, which has at least a pair of armature (side) outer portions 5a mounted on the (housing) outer portion 4a on the outer side of the movable fixture 19. The armature outer portions 5a form a magnetic circuit with the permanent magnets 3, and their magnetic field lines pass through the support portion 9 of the movable fixture 19. The armature outer portions 5a can be substantially the same size as the permanent magnets or larger. The armature outer portions 5a face the permanent magnets 3 so as to form an air gap therebetween, in which the movable portion of the movable fixture 19 is displaced.

[0037] The movable clamp 19 includes a coil 11 configured to be connected to an electrical circuit (not shown) that drives a current through the coil to move the movable clamp 19 during actuation of the clamp mechanism 1. The coil 11 is mounted within the support portion 9 of the movable clamp, for example, specifically within a coil mounting cavity 13 of the support portion 9. The support portion 9 can be formed as a substantially flat plate-shaped member that is translatable within the air gap formed between the permanent magnet 3 and the magnetic armature 5. The height H of the coil within the support portion 9 can be comparable to or approximately equal to the height H1 of the permanent magnet. The length L of the support portion 9 (as viewed in the translation direction D) is less than the length L1 of the permanent magnet 3 but greater than half the length of the permanent magnet 3. The length L of the support portion preferably corresponds to the length of the permanent magnet 3 minus the maximum displacement amplitude of the movable clamp. This ensures that the coil 11 is always within the air gap formed between the permanent magnet 3 and the magnetic armature 5 and always overlaps the permanent magnet 3, thereby ensuring maximum magnetic interaction.

[0038] The movable clamp further includes a clamp finger 10 or a holder for a clamp finger (hereinafter collectively referred to as a "clamp finger") that is formed integrally with the support portion 9 or formed separately and assembled to the support portion 9. The clamp finger can, in particular, protrude below the lower end of the housing 4, although in some applications it is also possible to have the clamp finger located within a housing or protective cover having an aperture to allow access to the component held by the clamp. The support portion 9 further includes a bearing portion 14 for supporting the movable portion 8b of the bearing 8.

[0039] Although in the illustrated embodiment, the gripper fingers 10 are schematically shown as substantially rectangular blocks, in actual application, the shape of the gripper fingers should be adapted to the shape of the component to be picked up. In an advantageous embodiment, the gripper fingers or a portion of the gripper fingers are removable and can be replaced by another gripper finger or part so that the shape or material can be changed depending on the object to be processed. This also allows for modification of various surface materials for the relevant application, such as with respect to hardness, friction, and other surface properties. Although in the illustrated embodiment, the gripper fingers are shown in a closed position (because they are in direct contact with each other), it should be noted that, depending on the application, the gripper fingers in the "closed" position can be separated by a gap. In many applications, the gripping function is achieved by moving the gripper fingers toward each other to clamp the object to be processed between them. However, within the scope of the present invention, the gripper fingers can be moved apart to clamp the object, for example, by being inserted into an orifice or cavity in the object.

[0040] To shift the movable clamp 19 between the open and closed positions, current is injected into the coil 11, thereby generating a magnetic field opposite to the magnetic field within the air gap at the position where the clamp is located during actuation. Due to the position of the N-N poles of the substantially plate-shaped permanent magnet 3 relative to the air gap and the support portion 9 of the movable clamp, the magnetic field passing through the coil 11 when the clamp is in the open position is generally opposite to the magnetic field passing through the coil when the clamp is in the closed position. To move the clamp from the open position to the closed position and back again to the open position, the direction of the current in the coil is reversed.

[0041] The movable clamps 19 may be interconnected by a mechanical system such as a rack and pinion or by a connecting arm, configured to ensure that the movable clamps move in opposite directions with equal amplitude and speed.

[0042] However, in a variant, the movable clamps may be controlled independently without any mechanical connection between them.

[0043] The clamp mechanism according to an embodiment of the present invention further comprises at least one magnetic locking mechanism 7 (magnetic lock 7a, 7b) configured to hold the movable clamp 19 in a clamped position (e.g., closed position) for processing an object. In an advantageous embodiment, the clamp mechanism comprises at least a second magnetic lock, such that the movable clamp is passively held magnetically in both the open and closed positions, whereby the displacement of the movable clamp from the open position to the closed position, and vice versa, is achieved by injecting a current in one direction or the opposite direction into the coil 11, depending on the direction of the magnetic field to be generated.

[0044] In the open and / or closed position, the current in the coil is either switched off or set to a lower amplitude than during actuation.

[0045] This advantageously provides a clamping mechanism which has low energy consumption and in particular generates little heat loss, whereby a particularly compact and lightweight clamping mechanism can be provided.

[0046] When performing handling functions requiring high clamping forces, the passive magnetic force of the magnetic lock acting on the clamp elements can be supplemented by an electromagnetic force provided by injecting current into the coil of the movable clamp 19 .

[0047] The magnetic lock may advantageously comprise permanent magnetic blocks 18a, 18b mounted to the housing 4 or the movable clamp 19, whereby the other of the movable clamp or the housing comprises ferromagnetic parts (ferromagnetic or soft magnetic material) 15a, 15b, or in a variant, permanent magnets.

[0048] In a first embodiment, the central magnetic lock 7a comprises a permanent magnet 18 mounted to the central portion 4b of the housing 4 and an associated ferromagnetic portion 15a mounted on the support portion 9 of the movable fixture, for example Figure 2 and6 shown.

[0049] In a second embodiment, the external magnetic lock 7b comprises a permanent magnet block 18 mounted on the (housing) exterior 4a and an associated ferromagnetic portion 15b mounted on the outer edge of the support portion 9 of the movable fixture, as shown in FIG. Figure 2 、 3a , 3b and Figures 4a to 4c In a variant, the magnetic locking mechanism 7 may comprise a combination of the above, so that a magnetic lock is provided on both the outer portion 4a and the central portion (interior) 4b of the housing, depending on the magnetic force to be generated by the locking mechanism.

[0050] In an advantageous embodiment, the stator and the movable clamp comprise a spacer element 21 which ensures that, in the fully locked and / or fully opened position, a gap is formed between the permanent magnet block 18 and the ferromagnetic parts (ferromagnetic or soft magnetic material) 15a, 15b of the magnetic locking mechanism 7. This gap can be formed by an air gap or an insert of non-magnetic material, such as Figure 5a In a variant, the spacer elements may be protrusions formed of magnetic material that contact the permanent magnet blocks 18, for example Figure 6 As shown, the reduced contact surface area reduces the magnetic attraction force between the clamp and the permanent magnet block.

[0051] The spacer element 21 advantageously allows avoiding excessively high peak magnetic locking forces that would require high electromagnetic forces to overcome.

[0052] As previously mentioned, the magnetic locking function can be configured to passively hold the movable clamp in an open (spaced) position rather than a closed position. In a variation, the magnetic locking function can be configured to passively hold the movable clamp in an open position and a closed position, such as Figure 5a 、 5b Shown schematically.

[0053] exist Figures 2 to 4c In the embodiment shown, the magnetic locking mechanism 7 (magnetic locks 7a, 7b) is formed, and the relevant magnetic elements (permanent magnet block 18, ferromagnetic portion 15b) are respectively installed on the outside 4a of the shell and on the outer end of the movable clamp 19 are configured so that when the movable clamp is in the closed position, the magnetic elements (permanent magnet block 18, ferromagnetic portion 15b) are in contact with each other directly or through the spacing element 21.

[0054] In an embodiment having a magnetic locking function in both the fully open and fully closed positions, the displacement stroke of the movable clamp 19 is configured so that when the movable clamp is in the closed position, the magnetic elements (permanent magnet block 18, ferromagnetic part 15b) contact each other at one end of the shell, and when the movable clamp is in the open position, the magnetic elements (permanent magnet block 18, ferromagnetic part 15b) contact each other at the other end of the shell directly or through the spacer element 21.

[0055] In one embodiment, the permanent magnet 18 is mounted in a ferromagnetic cap or U-shaped ferromagnetic element 22 mounted in the end wall of the (housing) exterior 4a. The function of the U-shaped ferromagnetic element is to increase and generate a more continuous magnetic force around the locking element.

[0056] Reference Signs List

[0057] Clamping mechanism 1

[0058] Stator 2

[0059] Permanent magnet 3

[0060] Magnetic circuit armature 5

[0061] Armature (side) outer 5a

[0062] Shell 4

[0063] External 4a

[0064] Center (inside) 4b

[0065] Support frame 16

[0066] Carrying portion 17

[0067] Bearing 8

[0068] Fixing portion 8a

[0069] Activity section 8b

[0070] Active fixture 19

[0071] Supporting portion 9

[0072] Coil installation cavity 13

[0073] Coil 11

[0074] Clamp finger 10 (clamp insert)

[0075] Clamp insert (replaceable - not shown)

[0076] Carrying portion 14

[0077] Magnetic locking mechanism 7

[0078] Center magnetic lock 7a

[0079] External magnetic lock 7b

[0080] Permanent magnet 18

[0081] Complementary magnetic locking parts 15a, 15b (ferromagnetic parts or ferromagnetic / soft magnetic materials or permanent magnets) spacer element 21

[0082] Ferromagnetic components (ferromagnetic armature) 22

Claims

7. The swiftly and minutely adjusting device for a wood-planer working table as claimed in claim 1, wherein said linking rod and said adjusting base are pivotally connected to each other with a bolt, and said bolt has a round shank to contact with said linking rod. said linking rod being connected to said linking rod 2. The clamping mechanism according to claim 1, wherein: The magnetic locking mechanism includes a second permanent magnet block, which is arranged so that the movable clamp is held in the open position and the closed position by magnetic force.

3. The clamping mechanism according to claim 1, wherein: The movable clamp and the stator include spacer elements at abutting locations between the movable clamp and the stator in the open and / or closed position, the spacer elements being configured to maintain a magnetic field gap between the first permanent magnet block and the complementary soft magnetic material portion or magnet.

4. The clamping mechanism according to claim 1, wherein: The first permanent magnet block of the magnetic locking mechanism is positioned substantially centrally between the movable clamps in the translation direction of the movable clamps.

5. The clamping mechanism according to claim 4, wherein: The movable fixture includes a ferromagnetic portion complementary to a first permanent magnet block or a second permanent magnet block mounted on a housing of the stator.

6. The clamp mechanism according to claim 2, wherein: The stator includes a shell exterior, and at least one of the second permanent magnet blocks is mounted on one of the shell exterior of the stator and one end of the movable fixture, and at least one of the complementary soft magnetic material parts or magnets is mounted on the other of the shell exterior and the end of the movable fixture.

7. The clamp mechanism according to claim 1, wherein: The permanent magnet is substantially flat in shape and has a thickness substantially smaller than the length or height of the permanent magnet viewed in a plane parallel to the displacement direction of the movable fixture, the thickness being measured in a direction orthogonal to the plane parallel to the displacement direction.

8. The clamp mechanism according to claim 7, wherein: The permanent magnet is substantially flat and rectangular in shape.

9. The clamp mechanism according to claim 1, wherein: The stator includes a magnetic circuit armature including armature outer portions made of a soft magnetic material mounted on opposite outer sides of the housing so that an air gap is formed between the armature outer portions and the permanent magnets, in which the coil of the movable fixture is positioned and displaced.

10. The clamp mechanism according to claim 9, wherein: The armature exterior has a substantially equal or larger surface area facing the permanent magnet.

11. The clamp mechanism according to claim 10, wherein: The armature outer portion is a substantially flat and thin portion.

12. The clamp mechanism according to claim 4, wherein: The permanent magnet is centrally positioned between the coils of a pair of movable clamps, and the N-S poles of the permanent magnet are arranged in a direction substantially parallel to the translation direction of the movable clamp.

13. The clamp mechanism according to claim 1, wherein: The length of the coil of each movable jig in the translation direction of the movable jig is smaller than the length of the permanent magnet in the translation direction of the movable jig.

14. The clamp mechanism according to claim 13, wherein: The length of the coil in the translation direction of the movable jig is 70% smaller than the length of the permanent magnet in the translation direction of the movable jig.

15. The clamp mechanism according to claim 13, wherein: The length of the coil in the translation direction of the movable jig is 60% smaller than the length of the permanent magnet in the translation direction of the movable jig.

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