End effector
The end effector addresses complex control issues by employing a roller and telescopic mechanism with mechanical torque control, facilitating efficient and reliable lid operation with reduced complexity and risk of damage.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-06-22
- Publication Date
- 2026-03-17
AI Technical Summary
Existing end effectors for screw-on containers require complex electrical control for opening and closing the lid, complicating the setup and increasing the risk of lid deformation or leakage due to improper torque application.
An end effector with a lid gripping portion featuring multiple rollers and a telescopic mechanism, allowing simple mechanical control through a torque limiter to manage lid opening and closing, ensuring stable grip and appropriate torque application.
Enables simple and reliable opening and closing of screw-on container lids with reduced risk of deformation or leakage, using mechanical torque control to prevent overtightening and accommodate various lid sizes and shapes.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an end effector capable of opening and closing the lid of a screw-on container.
Background Art
[0002] There are processes of opening and closing the lid to take out powders such as seasonings filled in screw-on containers, or opening and closing the lid to mix liquids such as paints. In recent years, the automation of processes has been promoted, and efforts have been made to improve the efficiency and shorten the time of processes and reduce labor costs by having industrial robots take over the opening and closing process of screw-on containers. For example, an end effector that opens and closes the lid of a screw-on container by a robot arm, as disclosed in Patent Document 1, has been considered.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, since the end effector described in Patent Document 1 has a configuration in which the lid chuck grips the lid portion from the left and right directions, it is necessary to electrically control the opening and closing operation of the lid chuck using a motor or the like. Therefore, the settings for controlling the opening and closing of the lid chuck become complicated.
[0005] <m Therefore, an object of the present invention is to provide an end effector capable of opening and closing the lid of a screw-on container with simple control.
Means for Solving the Problems
[0006] The end effector according to the present invention is an end effector capable of opening and closing the lid of a screw-on container, comprising: a container body gripping portion capable of gripping the container body of the screw-on container; a lid gripping portion positioned vertically above the container body gripping portion and capable of gripping the lid of the screw-on container; a motor for rotating the lid gripping portion; a lifting portion for raising and lowering the lid gripping portion; an extendable portion that supports the lid gripping portion via a vertically extendable spring; and a torque control unit that limits the torque when tightening the lid to a predetermined value or less, wherein the lid gripping portion has three or more finger portions arranged to surround the rotation axis of the lid gripping portion, and a plurality of rollers attached to the lower end of each of the finger portions, wherein the rotation axis of each of the plurality of rollers is perpendicular to the plane including the rotation axis of the lid gripping portion, and the vertical distance from each rotation axis to the rotation axis of the lid gripping portion is equal, and furthermore, a circle circumscribing each of the plurality of rollers with the rotation axis of the lid gripping portion as the center The minimum diameter is positioned to be smaller than the diameter of the lid. As the lifting mechanism lowers the lid gripping section, the lid of the screw-on container, gripped by the container body gripping section, is inserted into the space surrounded by multiple rollers. Each of the multiple rollers elastically deforms to grip the lid. With the lid gripping section gripping the lid screwed onto the container body, the motor rotates the lid gripping section in the lid-opening direction, releasing the lid from the container body. With the lid gripping section still gripping the lid that has been released from the container body, the lifting mechanism lowers the lid gripping section, pressing the lid against the opening of the container body supported by the container body gripping section. The motor rotates the lid gripping section in the lid-closing direction, screwing the lid onto the container body. The telescopic section contracts with the motor's rotation when the lid is opened, raising the lid gripping section, and expands with the motor's rotation when the lid is closed, lowering the lid gripping section. [Effects of the Invention]
[0007] According to the present invention, an end effector is provided that allows the lid of a screw-on container to be opened and closed with simple control. [Brief explanation of the drawing]
[0008] [Figure 1] A diagram showing the schematic configuration of the end effector according to the first embodiment. [Figure 2]Diagram illustrating the operation of the end effector according to the first embodiment. [Figure 3] A diagram showing the schematic configuration of the end effector according to the second embodiment. [Figure 4] A diagram showing the schematic configuration of the end effector according to the third embodiment. [Figure 5] A diagram showing the schematic configuration of the end effector according to the fourth embodiment. [Modes for carrying out the invention]
[0009] [First Embodiment] Figure 1 shows a schematic configuration of an end effector according to the first embodiment. Figure 1(a) is a front view of the end effector 1, and Figure 1(b) is a view from the A-A' direction of Figure 1(a).
[0010] The end effector 1 comprises a container body gripping section 102, a lid gripping section 114, an extendable section 111, a motor 108, and a torque control section 112. The end effector 1 is a device that performs both the removal of the lid 106 screwed onto the container body 116 of a screw-type container 101 and the attachment of the lid 106 to the container body 116.
[0011] The container body gripping portion 102 grips the container body 116 of the screw-on container 101. The gripping method may be, for example, to bring the container body 116 into contact with the inside of a V-shaped component and press the container body 116 against the V-shaped component using an air cylinder or an electric cylinder, or to use a member having a gripping surface that conforms to the outer circumferential surface of the container body 116 and clamp the container body 116 from opposing sides with a drive mechanism such as a motor (the method disclosed in Patent Document 1). The container body 116 is gripped by the container body gripping portion 102, which prevents the container body 116 from rotating together with the lid 106 when the lid gripping portion 114, described later, rotates the lid 106 in the opening or closing direction.
[0012] The lid gripping portion 114 is positioned vertically above the container body gripping portion 102 and is the part for gripping the lid 106 of the screw-on container 101. The lid gripping portion 114 comprises a plurality of finger portions 103 arranged to surround the rotation axis X of the lid gripping portion 114, and rollers 104 attached to the lower end of each of the finger portions 103.
[0013] The finger portions 103 are members for pressing the outer surface of the roller 104 against the lid 106 of the screw-on container 101. The number of finger portions 103 is preferably three or more to ensure stable holding of the lid 106. The finger portions 103 are preferably arranged so as to be rotationally symmetrical with respect to the rotation axis X of the lid gripping portion 114. Furthermore, for example, if the lid 106 is a cube such as a square lid, it is preferable to have four finger portions 103 to grip the container body 116 from four directions, thereby preventing the lid 106 from falling off from the side of the lid that is not being gripped.
[0014] Each of the rollers 104 is rotatably attached to the lower end of the finger portion 103 such that a portion of its outer surface faces the rotation axis X of the lid gripping portion 114. More specifically, the rotation axis of each roller 104 is perpendicular to the plane containing the rotation axis X of the lid gripping portion 114 (shown by the dashed line in Figure 1(b)), and the vertical distance from each rotation axis of the roller 104 to the rotation axis X of the lid gripping portion 114 is equal. Furthermore, the minimum diameter of the circle C that circumscribes each of the multiple rollers 104, centered on the rotation axis X of the lid gripping portion 114, is smaller than the diameter of the lid 106.
[0015] At least the outer surface of the roller 104 is made of an elastic material. For example, rubber can be used as the elastic material that makes up the outer surface of the roller 104. When rubber is used for the outer surface of the roller 104, it is preferable to use rubber that has a tensile strength of 1 MPa or more and 50 MPa, an elongation of 100% or more, and a Poisson's ratio of 0.4 or more and 0.5 or less.
[0016] The rotation axis X of the lid gripping part 114 coincides with the rotation axis of the motor 108, and the lid gripping part 114 can be rotated by the rotational force of the motor 108. Further, the lid gripping part 114 can be moved in the vertical direction by an elevating part described later.
[0017] A contact part 107 is provided at a portion of the lid gripping part 114 surrounded by the rollers 104 (finger parts 103). The contact part 107 abuts against the upper end surface of the lid 106 inserted into the space surrounded by the rollers 104, and is provided to position the lid 106 with respect to the rollers 104.
[0018] The telescopic part 111 is provided between the motor 108 and the lid gripping part 114, and supports the lid gripping part 114 via a spring 117 that can be telescoped in the vertical direction (up and down direction). The telescopic part 111 is composed of, for example, a plate-like plate 109 having a through hole, a spring 117 provided between the plate 109 and the lid gripping part 114, and a rod 110 inserted into the through hole of the plate 109 and the spring 117. The lower end of the rod 110 is fixed to the lid gripping part 114. As the spring 117 expands and contracts, the position of the lid gripping part 114 with respect to the plate 109 is variable.
[0019] The motor 108 is variable in the forward rotation direction and the reverse rotation direction (the opening and closing direction of the lid 106), and rotates the telescopic part 111 and the lid gripping part 114. The motor 108 only needs to have the torque for opening the lid 106, and a motor whose rotation speed satisfies the rotation speed required in the tact time in the automation process may be selected.
[0020] The torque control part 112 is a member that limits the torque when the lid 106 is tightened to a position below a predetermined position, and can prevent deformation and breakage due to over-tightening of the lid 106. As the torque control part 112, a mechanical torque limiter (for example, one using a friction plate and a spring) that does not require external power and electric control may be used, or a configuration that electrically senses fluctuations in the torque value such as a torque encoder and stops the rotation of the motor 108 may also be used.
[0021] The motor 108 and the telescopic part 111 (lid gripping part 114) are connected, for example, via a coupling 113 for absorbing the alignment between the motor 108 and the lid gripping part 114 and the telescopic part 111. As the coupling 113, for example, one having both the functions of a torque limiter and a coupling may be used.
[0022] The motor 108, the telescopic part 111 and the lid gripping part 114 are attached to a lifting part (not shown) such as a robot arm or various lifting devices and are movable in the vertical direction.
[0023] The method for opening and closing a screw-type container by the end effector 1 according to the present embodiment will be described. FIG. 2 is a diagram for explaining the operation of the end effector according to the first embodiment.
[0024] FIG. 2(a) shows a state before the lid gripping part 114 grips the lid 106. The container body 116 of the screw-type container 101 is gripped and fixed by the container body gripping part 102. The lid gripping part 114 is disposed vertically above the container body 116 and at a position where the rotation axis X of the lid gripping part 114 and the rotation axis of the lid 106 substantially coincide.
[0025] Figure 2(b) shows the state in which the lid gripping part 114 grips the lid 106 and the lid 106 is tightened. From the state in Figure 2(a), when the lifting part lowers the lid gripping part 114, the lid 106 is inserted into the space surrounded by the multiple rollers 104 as it descends. As described above, the rollers 104 are arranged such that the smallest diameter of the circle circumscribing the rollers 104 in the space surrounded by the rollers 104 is smaller than the outer diameter of the lid 106. However, since the outer circumferential surface of the rollers 104 is formed of an elastic material, the lid 106 is inserted into the space surrounded by the multiple rollers 104 by the elastic deformation of each of the multiple rollers 104. The reaction force generated by the elastic deformation of the surface of the rollers 104 acts as an external force to prevent the lid 106 from falling off, so that the lid gripping part 114 can grip the lid 106. By lowering the lid gripping portion 114 until the upper end surface of the lid 106 contacts the abutment portion 107, the lid 106 can be positioned to be stably held by the roller 104. Furthermore, by lowering the motor 108 until the spring 117 of the telescopic portion 111 is compressed by a certain amount, the lid 106 can be reliably brought into contact with the abutment portion 107 and positioned relative to the roller 104, regardless of variations in the position and size of the lid 106 in the height direction. Note that in the state shown in Figure 2(b), the spring 117 is extended, and the length of the spring 117 is approximately the same as in the initial state shown in Figure 2(a).
[0026] Figure 2(c) shows the state in which the lid gripping part 114 is gripping the lid 106 and the lid 106 has been removed. From the state in Figure 2(b), the motor 108 rotates the lid gripping part 114 in the opening direction of the lid 106. Since the lid gripping part 114 is connected to the motor 108 via the telescopic part 111, the lid gripping part 114 rises while the telescopic part 111 retracts as the lid 106 is opened. At this time, the amount of rise of the lid gripping part 114 is absorbed by the telescopic part 111, so it is not necessary to adjust the vertical position of the motor 108 and the telescopic part 111 in conjunction with the rise of the lid gripping part 114 (Figure 2(c)).
[0027] Once the screw-on engagement of the lid 106 with the container body 116 is released, the lifting mechanism raises the lid gripping mechanism 114, separating the container body 116 from the lid 106. The determination of whether or not the screw-on engagement has been released may be made, for example, based on the torque value detected by the torque control unit 112.
[0028] The operation of the end effector 1 for opening the lid 106 has been described above, but closing the lid can be done in the reverse order of opening. Specifically, with the lid gripping part 114 gripping the lid 106, the lid gripping part 114 is lowered to press the lid 106 against the opening of the container body 116, and the lid gripping part 114 is further lowered until the spring 117 of the telescopic part 111 is completely contracted. Next, the motor 108 is rotated in the closing direction of the lid 106, causing the lid 106 to screw onto the container body 116. As the lid 106 is closed, the spring 117 of the telescopic part 111 extends, causing the lid gripping part 114 to descend in accordance with the lid 106. When the lid 106 is fully tightened, the torque control unit 112 cuts off the power transmission from the motor. This prevents damage to the lid 106 due to excessive screwing. Subsequently, the lifting mechanism raises the lid gripping portion 114, separating it from the lid 106, and the sealing process is completed.
[0029] As described above, the end effector 1 according to the first embodiment is provided with elastically deformable rollers 104 at the lower end of the finger portions 103 of the lid gripping portion 114, and is arranged such that when the lid gripping portion 114 is not gripping the lid 106, the minimum diameter of the circle circumscribing each of the multiple rollers 104 is smaller than the diameter of the lid 106. Therefore, by simply inserting the portion of the lid 106 of the screw-on container 101 into the space surrounded by the rollers 104, the lid 106 can be gripped by the elastic deformation of the rollers 104. Accordingly, the end effector 1 according to this embodiment can grip the lid 106 without using a complex mechanism and control that would require opening and closing the finger portions in an opposing position using a drive mechanism such as a motor to grip the lid.
[0030] Furthermore, the end effector 1 according to this embodiment is equipped with a torque control unit 112. Therefore, if the torque exceeds a certain value when tightening the lid 106, the power transmission from the motor 108 is cut off, preventing deformation and damage to the lid 106 due to overtightening. In addition, since the lid 106 can be tightened with the appropriate torque, it is possible to suppress the lid 106 from loosening and the contents from leaking out during processes that apply vibration to the screw-type container 101, such as stirring. In the prior art (for example, Patent Document 1), a position sensor is provided on the linear guide, and the screw-in operation is stopped by estimating whether the screw-in of the lid has reached the stopping position from the displacement of the linear guide. In this case, there is a possibility that the lid cannot be closed with the appropriate torque, and there is a risk that the lid will loosen and the contents will leak out during processes that apply vibration to the screw-type container 101, such as stirring.
[0031] Furthermore, by using a mechanical torque limiter that does not require external power or electrical control as the torque control unit 112, the problem that occurs when the cover 106 is overtightened can be easily resolved without using a position sensor that requires electrical control.
[0032] [Second Embodiment] The end effector 2 according to the second embodiment will be described using Figure 3. Figure 3 is a diagram showing the schematic configuration of the end effector according to the second embodiment. The differences from the first embodiment in this embodiment will be explained.
[0033] The lid gripping portion 114 includes a first bolt 201 and a second bolt 202. The first bolt 201 passes through the base portion 203 of the gripping portion 114 and is connected to the abutment portion 107, allowing the lower end position of the abutment portion 107 relative to the roller 104 to be adjusted. This makes it possible to accommodate lids 106 of various heights, as shown in Figures 3(a) and 3(b).
[0034] The second bolt 202 is connected to the finger portion 103 by passing through a member that hangs down from near the outer peripheral edge of the base portion 203 of the lid gripping portion 114. As the second bolt 202 rotates, the finger portion 103 and the roller 104 can move together, and the vertical distance between the rotation axis of each roller 104 and the rotation axis X of the lid gripping portion 114 can be adjusted. This makes it possible to accommodate lids 106 of various diameters, as shown in Figures 3(a) and 3(b). Furthermore, by changing the vertical distance between the rotation axis of each roller 104 and the rotation axis X of the lid gripping portion 114 according to the material of the lid 106, the gripping force of the lid 106 can be maintained. For example, if the lid 106 is made of a soft material, if the gripping force is too great, the lid 106 may deform, and the screws may not engage when screwing it in, but this can be mitigated by increasing the vertical distance. Alternatively, instead of using the second bolt 202, the radial distance of the finger portion 103 may be adjusted by a mechanism such as a scroll chuck used in lathes, in which the finger portion moves in conjunction with the rotation of the handle.
[0035] [Third Embodiment] The end effector 3 according to the third embodiment will be described using Figure 4. Figure 4 is a diagram showing the schematic configuration of the end effector according to the third embodiment. The differences from the first embodiment in this embodiment will be explained.
[0036] In the end effector 3, the roller 104 is connected to the gripping part 114 by a link mechanism 302, and at the same time, it is connected to the base part 203 of the gripping part 114 by an expandable / contractable mechanism 304 that expands and contracts using a spring or the like. With this configuration, the end effector 3 can automatically adjust the vertical distance between the rotation axis of each of the multiple rollers 104 and the rotation axis X of the lid gripping part 114. This makes it possible to grip two or more lids 106 of different diameters during the automated process, as shown in Figures 4(a) and 4(b). For example, when gripping a lid 106 with a large diameter, as the lid gripping part 114 descends and the lid 106 is inserted into the space surrounded by the multiple rollers 104, the rollers 104 are displaced in the direction that the expandable / contractable mechanism 304 contracts. As a result, the space surrounded by the multiple rollers 104 expands, making it possible to grip a lid 106 with a large diameter. Furthermore, the spring force of the compressed expansion / contraction mechanism 304 can hold the lid 106 in place, preventing it from detaching.
[0037] [Fourth Embodiment] The end effector 4 according to the fourth embodiment will be described using Figure 5. Figure 5 is a diagram showing the schematic configuration of the end effector according to the fourth embodiment. The differences from the first embodiment in this embodiment will be explained.
[0038] The end effector 4 has a configuration suitable for a screw-on container 101 equipped with a lid 106 with a nozzle. Specifically, the lid 106 is fixed by a lid gripping portion 401 which corresponds to the container body gripping portion 102 of the first embodiment, and the container body 116 is gripped by a container body gripping portion 402 which corresponds to the lid gripping portion 114. In this case, the end effector 4 is positioned such that the nozzle of the lid 106 faces upward, with the lid gripping portion 401 positioned vertically above the container body gripping portion 402, and when opening or closing the lid 106, the container body 116 is rotated relative to the lid 106. With this configuration, leakage of contents due to the nozzle facing downward can be prevented.
[0039] Furthermore, when gripping the outer surface of the lid 106 and pushing in the container body 116, it is desirable to provide the lid gripping portion 401 with a configuration that allows the top of the nozzle to abut against it in order to suppress axial slippage that occurs between the outer surface of the lid 106 and the inner surface of the lid gripping portion 401. [Industrial applicability]
[0040] The end effector according to the present invention can be used as a robot for opening and closing the lid of a screw-on container. [Explanation of symbols]
[0041] 1,2,3,4 End effectors 101 Screw-in container 102 Container body gripping part 103 Finger part 104 Laura 106 Lid 107 Buttocks 108 Motor 111 Telescopic part 112 Torque Control Unit 114 Lid grip part 116 Container body 117 Spring X Rotation axis of the lid grip
Claims
1. An end effector capable of opening and closing the lid of a screw-on container, A container body gripping portion capable of gripping the container body of the aforementioned screw-type container, A lid gripping portion is positioned vertically above the container body gripping portion and capable of gripping the lid of the screw-on container, A motor that rotates the lid gripping portion, A lifting mechanism for raising and lowering the lid gripping portion, An expandable part that supports the lid gripping part via a spring that can expand and contract in the vertical direction, The system includes a torque control unit that limits the torque when tightening the lid to a predetermined value or less, The aforementioned lid gripping portion is, Three or more finger portions are arranged to surround the rotation axis of the lid gripping portion, It has a plurality of rollers attached to the lower end of each of the aforementioned finger parts, The plurality of rollers are arranged such that their respective axes of rotation are perpendicular to the plane containing the axis of rotation of the lid gripping portion, the vertical distance from each axis of rotation to the axis of rotation of the lid gripping portion is equal, and furthermore, the minimum diameter of the circle circumscribing each of the plurality of rollers, centered on the axis of rotation of the lid gripping portion, is smaller than the diameter of the lid. As the lifting mechanism lowers the lid gripping portion, the lid of the screw-on container, which is gripped by the container body gripping portion, is inserted into the space surrounded by the plurality of rollers, and each of the plurality of rollers elastically deforms to grip the lid. With the lid gripping portion gripping the lid screwed onto the container body, the motor rotates the lid gripping portion in the lid-opening direction, thereby detaching the lid from the container body. With the lid gripping portion gripping the lid that has detached from the container body, the lifting portion lowers the lid gripping portion to press the lid against the opening of the container body supported by the container body gripping portion, and the motor rotates the lid gripping portion in the closing direction of the lid, thereby screwing the lid onto the container body. The aforementioned extendable portion is an end effector that, when the lid is opened, contracts in accordance with the rotation of the motor, raising the lid gripping portion, and when the lid is closed, extends in accordance with the rotation of the motor, lowering the lid gripping portion.
2. The end effector according to claim 1, further comprising an adjustment mechanism capable of changing the vertical distance between the rotation axis of each of the plurality of rollers and the rotation axis of the lid gripping portion.
3. The end effector according to claim 1, further comprising a stopper portion that abuts against the upper end surface of the lid inserted into the space surrounded by the plurality of rollers, and positions the outer circumferential surface of the lid relative to the rollers.
4. The end effector according to claim 3, further comprising an adjustment mechanism capable of adjusting the lower end position of the abutment portion for the plurality of rollers.
5. The outer surface of the roller is made of rubber. The end effector according to claim 1, wherein the rubber has a tensile strength of 1 MPa or more and 50 MPa, an elongation rate of 100% or more, and a Poisson's ratio of 0.4 or more and 0.5 or less.
Citation Information
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