Article holding device, and article holding method using the same

Abstract

To provide an article holding device which can hold a plurality of kinds of containers in an appropriate position, and an article holding method using the same.SOLUTION: An article holding device 1 includes a base 10, and a plurality of holding arms 20 which is rotatably supported by the base 10, and has article contact parts 28 which can contact with an article B placed on a placing surface 17. Three or more holding arms 20 are arranged around the placing surface 17. The plurality of holding arms 20 rotates respectively so that the article contact parts 28 move between an approaching position in which they approach each other and a release position in which they separate from each other. The article contact part 28 is biased in a direction from the release position to the approaching position by the biasing member 30. A first free end 21b serving as an external force applying part by which external force can be applied against biasing force by the biasing member 30 is arranged on an end part side opposite to an end part side with the article contact part 28 arranged.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an article gripping device and an article gripping method using the same.

Background Art

[0002] Bottle-shaped products filled with internal liquids such as liquid cosmetics and shampoos are produced by performing processes such as filling the internal liquid, attaching caps, labeling, and printing on containers conveyed on a conveyor. In order to perform such processes smoothly, it is important that the container is maintained in an upright state during the conveyance process of the container.

[0003] As a technique for realizing this, for example, a technique of holding a container using an article gripping device and conveying the entire article gripping device is known. Examples of such an article gripping device include those described in Patent Document 1 and Patent Document 2.

[0004] The article gripping device described in Patent Document 1 includes a holder main body for housing a container and a support member placed on the bottom surface portion of the holder main body for supporting the container so as to be able to move up and down. Specifically, the article gripping device described in Patent Document 1 is movably provided within the support member, and includes a pair of holding claws that fit into a recess formed in the bottom surface of the container, an elastic member interposed between the pair of holding claws for elastically widening the distance between these holding claws, a first permanent magnet provided within the support member for moving the distance between the pair of holding claws in a direction of approaching when receiving a repulsive force, and a second permanent magnet provided on the main body holder for generating a repulsive force with the first permanent magnet. According to such an article gripping device, by fitting a pair of holding claws into a recess formed in the bottom surface of the container, the container can be held upright and centering and positioning of the container can be performed. As a result, in the article gripping device described in Patent Document 1, the upright-held container can be conveyed in a centered state, etc., so that processes such as filling the internal liquid can be performed smoothly.

[0005] The article gripping device described in Patent Document 2 comprises a holder body for storing a container, a pair of opposing grip pillars having lower ends rotatably supported by the holder body, interlocking means provided at the lower ends of the pair of grip pillars to interlock and raise / lower the grip pillars, biasing means for biasing the pair of grip pillars in the closing direction, a container gripping member provided at the top of the grip pillars, and a pressure receiving part extending from the lower ends of the grip pillars to open and close the pair of grip pillars upon receiving external pressure. With such an article gripping device, by moving a pair of gripping columns in the closing direction, it is possible to transport an upright-held container in a state where it has been centered and positioned, similar to the article gripping device described in Patent Document 1. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 08-040495 [Patent Document 2] Japanese Patent Application Publication No. 03-289487 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, since the article gripping devices described in Patent Document 1 and Patent Document 2 are configured to grip the container while it is housed inside the holder body, depending on the shape and size of the container (hereinafter referred to as "shape, etc."), it may not be possible to insert it into the holder body. As a result, it becomes necessary to prepare a separate article gripping device that is suitable for the shape, etc. of the container. In such cases, not only does the manufacturing burden of the article gripping device increase, but the burden of securing storage space for storing the article gripping device and the work of replacing the article gripping device in the transport means also increases.

[0008] Furthermore, the article gripping device described in Patent Document 1 requires the formation of recesses on the bottom surface of the container that can engage with a pair of retaining claws, which limits the freedom of the container's shape.

[0009] On the other hand, the article gripping device described in Patent Document 2 has a configuration in which a container is gripped from two sides by a pair of grip pillars that move in the same straight line in a plan view. Therefore, depending on the cross-sectional shape of the container, it may be difficult to properly center and position the container.

[0010] Thus, the article gripping devices described in Patent Documents 1 and 2 cannot be said to adequately accommodate containers of different shapes and other characteristics, and there is still room for improvement.

[0011] The present invention relates to providing an article gripping device and an article gripping method using the same, which can overcome the drawbacks of the conventional technology described above. [Means for solving the problem]

[0012] The present invention relates to an article gripping device comprising a base having an article mounting portion, and three or more gripping arms arranged around the aforementioned mounting portion. Each of the plurality of gripping arms is rotatably supported on the base and has an article contact portion on one end that can contact an article placed on the aforementioned mounting portion, and each of the gripping arms rotates to move between an approach position where the article contact portions are close to each other and a release position where they are separated from each other, and the article contact portions are biased by a biasing member in the direction from the release position to the approach position, and preferably has an external force application portion provided on the end opposite to the one end, which can apply an external force to resist the biasing force by the biasing member.

[0013] The present invention relates to a method for gripping an article using the article gripping device described above. Preferably, the article gripping method includes an external force application step of applying an external force to the external force application part to move a plurality of gripping arms from the approach position to the release position; an article placement step of placing an article on the aforementioned placement part after the external force application step; and an external force release step of releasing the external force applied to the external force application part after the article placement step to move the gripping arms from the release position toward the approach position and bring the article contact part into contact with the article. [Effects of the Invention]

[0014] The article gripping device and article gripping method using the present invention make it possible to grip multiple types of containers with different shapes and other characteristics in the correct position. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a schematic perspective view of the article gripping device according to this embodiment. [Figure 2] Figure 2 is a schematic perspective view of an object gripping device, viewed from a different angle than Figure 1. [Figure 3] Figure 3 is a schematic perspective view of an article gripping device, viewed from a different angle than Figures 1 and 2. [Figure 4] Figure 4 is a schematic side view illustrating the operation of the item gripping device, where (a) shows the container being gripped by the gripping arm, and (b) shows the gripping arm in the released position, viewed from the same direction as in (a). [Figure 5] Figure 5 is a schematic side view illustrating the operation of the article gripping device, where (a) is a view of the article gripping device of Figure 4(a) from a different direction, and (b) is a view of the article gripping device 1 of Figure 4(b) from the same direction as (a). [Figure 6] Figure 6 is a schematic plan view illustrating the arrangement of the biasing members. [Figure 7] Figure 7 is a schematic perspective view showing the gripping arm of the article gripping device according to the second embodiment in a close-proximity position. [Figure 8]FIG. 8 is a schematic perspective view showing a state in which the gripping arm of the article gripping device in FIG. 7 is in the release position. [Figure 9] FIG. 9 shows a schematic plan view in the production line of the bottle-shaped product, [Figure 10] FIG. 10 shows a schematic cross-sectional view taken along the line A-A in FIG. 9.

Mode for Carrying Out the Invention

[0016] Hereinafter, the article gripping device of the present invention and the article gripping method using the same will be described based on their preferred embodiments with reference to the drawings. FIGS. 1 to 3 show schematic perspective views of the article gripping device 1 according to the present embodiment.

[0017] [Overall Configuration of Article Gripping Device 1] As shown in FIGS. 1 to 3, the article gripping device 1 is a device for holding a container (see FIGS. 4 and 5, hereinafter referred to as "container B") upright on a conveyor (see FIGS. 4 and 5, hereinafter referred to as "conveyor C") in a production line for producing bottle-shaped products filled with internal liquids such as liquid cosmetics and shampoos. The article gripping device 1 according to the present embodiment includes a base 10, a plurality of gripping arms 20 for gripping the container B placed on the base 10, and a plurality of biasing members 30. In the production line using the article gripping device 1, the operation of placing the container B on the article gripping device 1 is performed in the same manner as in the production lines of other general bottle-shaped products. In the present embodiment, thereafter, operations such as filling the internal liquid into the container B and attaching a cap to the container B (post-processes) are performed. Note that the operation of placing the container B on the article gripping device 1 and the above-described post-processes may be performed in a state where the operation of the conveyor C is temporarily stopped, or may be performed while the conveyor C is operating without stopping it.

[0018] [Base 10] The base 10 is made of a member such as a resin material, and includes a lower member 11 and an upper member 16 arranged in upper and lower two stages. Both the lower member 11 and the upper member 16 have a roughly square plate shape when viewed from above or below (hereinafter referred to as "plan view"), and are positioned opposite each other with a gap between them, via rectangular cross-section support members 40 located at the four corners. For the sake of explanation, the space formed between the lower member 11 and the upper member 16 will be referred to as the storage space S. The lower member 11 and the upper member 16 may both be circular in shape or the like in a plan view, or they may have different shapes from each other. From the viewpoint of ensuring the stability of the article gripping device 1, it is preferable that the lower member 11 and the upper member 16 have the same shape, or that the lower member 11 is larger than the upper member 16 in a plan view. The storage space S is defined in the height direction by the space between the lower surface of the upper member 16 and the upper surface of the lower member 11, and in the plan direction by the larger of the upper member 16 and the lower member 11 in a plan view. That is, in the plan direction, the upper member 16 defines the storage space S in one range (size), and the lower member 11 defines the storage space S in other ranges (size). For example, if the lower member 11 is larger than the upper member 16 in a plan view, the lower member 11 defines the planar direction of the storage space S. As will be described later, the gripping arm 20 is positioned so that the container B is centered on the center of the upper member 16.

[0019] The lower member 11 is a member that is placed on the conveyor and has support parts 12 provided on each of the four sides 11a that make up the outer circumference, and an opening 13 (see Figure 2) that opens in the center. The support portion 12 has a pair of protruding pieces 12a, 12a that are spaced apart in the circumferential direction of the lower member 11, and each of the pair of protruding pieces 12a, 12a has a hole 12b through which the shaft member 41 can be inserted. As will be described in detail later, the gripping arm 20 is supported so as to be rotatable on the lower member 11 by inserting the shaft member 41 while sandwiched between the pair of protruding pieces 12a, 12a. In other words, in this embodiment, the number of gripping arms 20 is the same as the number of support portions 12, which is "4".

[0020] The opening 13 has a size and shape, such as a square shape, that allows a rod-shaped reciprocating member R (see Figures 4 and 5) provided on the conveyor side to be inserted through it. The shape of the opening 13 can be changed to another shape, such as a circular shape, provided that it is large enough to allow the reciprocating member R to pass through. The reciprocating member R will be described later. In this embodiment, a lower member 11 is provided as a member that rotatably supports the gripping arm 20, but this can be omitted. Such a configuration can be realized, for example, by providing a side wall that hangs down from the lower surface of the outer circumference of the upper member 16, and arranging a support part 12 that rotatably supports the gripping arm 20 on the inner surface of the side wall. With such a configuration, the lower end of the side wall can be placed directly on the conveying surface of the conveyor C, making it possible to press the first free end 21b with the reciprocating member R. In such a configuration, the space defined by the lower surface of the upper member 16, the opening surface formed by the lower end of the side wall, and the inner circumferential surface of the side wall becomes the storage space S.

[0021] The upper member 16 has a mounting section and a plurality of holes 18, and functions as a plate on which article B is placed. In this embodiment, the mounting section refers to the area on the upper surface of the upper member 16 that is surrounded by the plurality of holes 18 and on which article B can be placed (hereinafter referred to as the "mounting surface 17"). As described above, the mounting surface 17 constitutes a part of the upper surface of the upper member 16 and is formed in a smooth shape. As will be described in detail later, the multiple gripping arms 20 are configured such that the article contact portions 28 positioned above the mounting surface 17 move toward each other due to the biasing force of the biasing member 30, and grip the container B placed on the mounting surface 17 by sandwiching it from all sides (see Figures 4(a) and 5(a)). In other words, in this embodiment, the container B is moved toward the center of the mounting surface 17 as the multiple gripping arms 20 move, and then held in that position (hereinafter also referred to as "centering"). In this embodiment, since the mounting surface 17 is formed in a smooth shape, it is possible to smoothly move the container B placed on the mounting surface 17 toward the center of the mounting surface 17.

[0022] Furthermore, the mounting surface 17 is preferably shaped in a way that minimizes frictional resistance between it and the bottom surface of the container B. In addition to a smooth surface, it can also be, for example, a smooth uneven surface. A smooth uneven surface, in this context, means that the surface is formed in an uneven manner, and the height of the tips of the convex portions is approximately the same. In this case, it is preferable that the tips of the convex portions are formed in a smooth surface manner. By making the mounting surface 17 a smooth uneven surface, the contact area between the mounting surface 17 and the container B can be reduced, making it possible to move the container B smoothly. Also, if the surface of the upper member 16 is made of a material such as an elastomer that easily generates frictional resistance between it and the bottom surface of the container B, it is preferable to coat the mounting surface 17 with a coating material or adhesive member containing a resin component that minimizes frictional resistance.

[0023] Each of the multiple holes 18 has a trapezoidal shape that narrows towards the center of the mounting surface 17, corresponds to the number of support parts 12 that support the gripping arm 20, and is formed adjacent to the side portion 16a of the upper member 16. As will be described in more detail later, when the gripping arm 20 is assembled to the base 10, it passes through the holes 18 and is positioned to protrude from the upper surface of the upper member 16. The gripping arm 20 is movable within the range of the holes 18. If the hole 18 is closed, it is possible to prevent the gripping arm 20 from falling outward in the event that the biasing member 30, which will be described later, comes off. Note that the hole 18 is not limited to being closed, and may also be a so-called notch shape that opens outward from the upper member 16.

[0024] [Gripping arm 20] The gripping arm 20 is composed of a first extension portion 21 and a second extension portion 26. The first extended portion 21 is formed in the shape of a rectangular prism with a rectangular cross-section and has a fixed end 21a that is rotatably supported by the support portion 12 of the lower member 11, and a first free end 21b on the opposite side. The fixed end 21a has a hole (not shown) through which the shaft member 41 can be inserted. The lower surface of the first free end 21b is an inclined surface 21c that slopes upward toward the tip. As will be described later, the first free end 21b is an external force application portion to which a pressing force is applied by the reciprocating member R.

[0025] The second extension portion 26 is composed of a main body portion 27 having a plate shape and an article contact portion 28. The main body portion 27 has a connecting end 27a connected to the upper surface of the first extension portion 21 and a second free end 27b on the opposite side. The connecting end 27a is connected at a position slightly towards the fixed end 21a from the center between the fixed end 21a and the first free end 21b of the first extension portion 21 (see Figures 4 and 5). The article contact portion 28 has a substantially semi-cylindrical shape, and the curved surface 28a side of the curved side of the semi-cylindrical shape is connected to the second free end 27b such that it faces the first free end 21b side of the first extension portion 21. The article contact portion 28 is not limited to a substantially semi-cylindrical shape, but it is preferable that it has a curved surface shape that is convex outward.

[0026] The base 10 and the gripping arm 20 are assembled by positioning the fixed end 21a of the first extension 21 between a pair of protruding pieces 12a, 12a of the lower member 11, and then inserting the shaft member 41 through the holes 12b of the protruding piece 12a and the hole (not shown) of the fixed end 21a. As a result, the gripping arm 20 is rotatably supported with respect to the base 10, and the second free end 27b of the second extension 26 is positioned to protrude from the upper surface of the upper member 16. The four gripping arms 20 are also positioned at an angle of approximately 90 degrees apart.

[0027] A biasing member mounting portion 29 is attached to the main body portion 27 at a predetermined position between the connecting end 27a and the second free end 27b. The biasing member mounting portion 29 is a member made of resin material or the like for connecting adjacent gripping arms 20, 20 with a biasing member 30, and has two shaft portions 29a, 29a for attaching the biasing member 30. The biasing member mounting portion 29 has, for example, a rectangular prism shape or a cylindrical shape and is attached to the main body portion 27 so as to cover the periphery of the main body portion 27.

[0028] The two shaft portions 29a, 29a are arranged at a predetermined angular interval, for example, a 90-degree angle interval, and are placed in the storage space S with the biasing member mounting portion 29 attached to the main body portion 27, and are positioned to protrude toward the fixed end 21a side of the first extending portion 21. In this embodiment, the shaft portions 29a, 29a are provided around the main body portion 27 by attaching the biasing member mounting portion 29 to the second extending portion 26, but these can also be made into a single integrated unit.

[0029] With the four gripping arms 20 attached to the base 10, the curved surface 28a side of the article contact portion 28 each protrudes toward the center of the mounting surface 17, and the first free end 21b of the first extension portion 21 is positioned close to each other without interfering with each other. In this state, the biasing member mounting portion 29 attached to the second extension portion 26 is positioned below the upper member 16. In other words, in this embodiment, with the four gripping arms 20 assembled to the base 10, the main body 27 of the second extension 26 that penetrates the hole 18 and the article contact portion 28 are positioned above the upper member 16, while other components such as the first extension 21 and the biasing member 30 are housed in the storage space S below the upper member 16. Therefore, in this embodiment, only the minimum necessary components for gripping the article B are positioned above the upper member 16, making it possible to widen the area (placement area) of the mounting surface 17 on which the container B is placed.

[0030] Furthermore, it is preferable that the second extension portion 26 is connected to the first extension portion 21 at an inclination toward the first free end 21b. Specifically, to achieve this configuration, the angle θ on the first free end 21b side of the angle between the first extension 21 and the second extension should be set to less than 90 degrees (see Figures 4 and 5). By setting the angle θ to such a value, as shown in Figure 4, the curved surface 28a of the article contact portion 28 can be positioned closer to the center of the mounting surface 17 than when the angle θ is 90 degrees. As a result, in this embodiment, with the four gripping arms 20 assembled to the base 10, the curved surfaces 28a of the article contact portions 28 can be brought closer to each other. For this reason, in this embodiment, by setting the angle θ to less than 90 degrees, it is possible to grip articles B with a relatively small cross-sectional shape.

[0031] Furthermore, the connection position of the second extension portion 26 to the first extension portion 21 is not limited to a position slightly closer to the fixed end 21a, as shown in Figures 4 and 5, but can be set as appropriate. For example, the second extension portion 26 can be connected at a position even closer to the fixed end 21a than the position shown in Figures 4 and 5. This configuration allows for a wider area of ​​the mounting surface 17 on which the item B is placed. Thus, according to this embodiment, by appropriately setting the angle θ between the first extension portion 21 and the second extension portion 26, and the connection position of the second extension portion 26 to the first extension portion 21, the range of compatibility with multiple types of containers with different shapes and other characteristics can be increased. In other words, it can be made highly versatile.

[0032] In this embodiment, as shown in Figures 1 to 3, the fixed end 21a of the first extended portion 21 constituting the gripping arm 20 is configured to be rotatably supported by a support portion 12 provided on the side portion 11a of the lower member 11 of the base 10. Therefore, in this embodiment, the widthwise size of the lower member 11 can be reduced, resulting in a more compact overall product gripping device 1.

[0033] [Biasing member 30] The biasing member 30 according to this embodiment is a so-called tension spring and is positioned to span between the shaft portions 29a, 29a of adjacent biasing member mounting portions 29, that is, between adjacent gripping arms 20, 20. Specifically, the biasing member 30 is attached to the adjacent gripping arms 20, 20 by hooking the end of the biasing member 30 onto the shaft portion 29a of the biasing member mounting portion 29 attached to the gripping arm 20. In this embodiment, since there are four gripping arms 20, the number of biasing members 30 is also the same number, "4" (see Figure 6(a)).

[0034] As shown in Figures 1 to 3, the four gripping arms 20 are biased by the biasing members 30, with the biasing members 30 attached to the biasing member mounting portion 29, toward a position where the article contact portions 28 are close to each other (hereinafter referred to as the "close position").

[0035] As shown in Figures 4 and 5, in this embodiment, the conveyor C side on which the article gripping device 1 is installed is provided with a retractable member R that can move between a protruding position P1 that protrudes above the conveying surface of the conveyor C and a non-protruding position P2 that is below the conveying surface of the conveyor C. The reciprocating member R has a rod-like shape, with its tip formed into a curved surface. When the item gripping device 1 being transported stops at a predetermined position, the reciprocating member R moves from a non-protruding position P2 to a protruding position P1, and is positioned to pass through the opening 13 of the lower member 11. Alternatively, the reciprocating member R may be made to move in sync with the operation of the conveyor C that transports the item gripping device 1, allowing the reciprocating member R to move back and forth without stopping the conveyor C. In this embodiment, from the viewpoint of smoothly moving the reciprocating member R between the protruding position P1 and the non-protruding position P2, it is preferable to use a conveyor C consisting of two narrow belt conveyors arranged at a distance such that both ends of the item gripping device 1 rest on the narrow belt conveyors. However, this is not limited to this, and a conveyor such as a roller conveyor with conveying surfaces spaced apart along the transport path may also be used.

[0036] The retractable member R penetrates the opening 13 of the lower member 11 and, while in a protruding position P1, presses upward against each of the four first free ends 21b of the gripping arms 20. As described above, the four first free ends 21b of the gripping arms 20 are arranged in close proximity to each other, that is, they are arranged in a clustered state (see Figures 1, 4, and 5, etc.). Therefore, in this embodiment, by moving one retractable member R forward and backward, it is possible to move all four gripping arms 20 simultaneously. In this embodiment, the pressing force applied by the retractable member R to press upward against each of the first free ends 21b is an external force, and each first free end 21b is an external force application point that is pressed by the retractable member R.

[0037] In this embodiment, the tip of the reciprocating member R is formed in a curved shape, while the lower surface of the first free end 21b is an inclined surface 21c. Therefore, when the reciprocating member R moves toward the protruding position P1, it is possible to smoothly press the four first free ends 21b upward.

[0038] The four gripping arms 20 are configured such that when the retractable member R moves from a non-protruding position P2 to a protruding position P1 and presses against each first free end 21b, the curved surfaces 28a move toward a position where they are separated from each other (hereinafter referred to as the "release position"), against the biasing force of the biasing member 30 (see Figures 4(b) and 5(b)). In this embodiment, the container B is placed on the mounting surface 17 with the four gripping arms 20 in the release position.

[0039] On the other hand, when the reciprocating member R moves from the protruding position P1 to the non-protruding position P1, the biasing force of the biasing member 30 causes the four gripping arms 20 to move from the released position to the approaching position (see Figures 4(b) and 5(b)). As a result, the article B placed on the mounting surface 17 is gripped by the four article contact portions 28.

[0040] As described above, in this embodiment, since the biasing member 30 is attached between adjacent gripping arms 20, 20 (see Figure 6(a)), the biasing force of two biasing members 30 acts on one gripping arm 20. Therefore, in this embodiment, the biasing force acting on the gripping arm 20 can be increased, making it possible to grip the container B with a relatively high gripping force using the four article contact parts 28.

[0041] [Operation of the item gripping device 1] Next, the operation of the item gripping device 1 will be explained with reference to Figure 4. Figures 4 and 5 are schematic side views illustrating the operation of the article gripping device 1. Figure 4(a) shows the state in which the container B is gripped by the gripping arm 20, Figure 4(b) shows the gripping arm 20 in the released position as viewed from the same direction as in Figure 4(a), Figure 5(a) shows the article gripping device 1 of Figure 4(a) as viewed from a different direction, and Figure 5(b) shows the article gripping device 1 of Figure 4(b) as viewed from the same direction as in Figure 5(a).

[0042] For the sake of clarity, the following explanation will assume that the item gripping device 1 is installed on conveyor C. Furthermore, while Figures 4 and 5 illustrate the case of gripping a rectangular container B with a rectangular cross-section, other rectangular containers with polygonal shapes other than a quadrilateral cross-section, cylindrical containers, etc., are also acceptable.

[0043] As shown in Figures 4(b) and 5(b), in this embodiment, when the article gripping device 1 is transported by the conveyor C and the opening 13 of the lower member 11 is positioned directly above the retractable member R, the transport operation is temporarily stopped, and the retractable member R moves from the non-protruding position P2 towards the protruding position P1. As a result, the first free ends 21b of each of the four gripping arms 20 are pushed up, and the gripping arms 20 move from the approaching position to the release position against the biasing force of the biasing member 30. In other words, in this embodiment, the gripping arms 20 are configured to move from the approaching position to the release position when a pressing force from the retractable member R acts on the first free ends 21b, which act as external force application parts. In the following, the process of moving the gripping arm 20 described above to the release position will be referred to as the external force application process.

[0044] In this embodiment, in this state, the container B, which does not have a cap attached, is placed on the mounting surface 17 of the article gripping device 1 using a known transport means such as a robot, and then the reciprocating member R is moved from the protruding position P1 to the non-protruding position P2. As a result, the gripping arm 20 is moved from the release position to the approaching position by the biasing force of the biasing member 30, and the container B placed on the mounting surface 17 is gripped by the four article contact parts 28 arranged around it. In other words, since container B is pressed from all four sides, it moves towards the center of the mounting surface 17 and is then centered. Furthermore, in this embodiment, since the mounting surface 17 is formed as a smooth surface that does not generate much frictional resistance between it and the bottom surface of container B, it is possible to move the item B smoothly towards the center of the mounting surface 17. In the following, the process of placing the container B described above onto the mounting surface 17 is referred to as the item placement process, and the process of gripping the container B with the four gripping arms 20 is referred to as the external force release process.

[0045] In this embodiment, four gripping arms 20 are arranged at an angle of approximately 90 degrees apart, and the container B is gripped by these four gripping arms 20. Therefore, in this embodiment, the container B can be gripped from all four sides at equal intervals, allowing for good centering of the container B and enabling it to be held with a relatively high gripping force.

[0046] In this embodiment, the container B is gripped by four gripping arms 20, but the number of arms can be changed as appropriate, as long as it is three or more. In this case, the number of gripping arms 20 can be changed according to the cross-sectional shape of the container B. For example, the number of gripping arms 20 can be determined as three if the cross-sectional shape of the bottle B is triangular, and five if it is pentagonal. In this case, it is preferable to position each gripping arm 20 at an angle where the article contact portion 28 can contact each side of the bottle B, for example, at an angle of 120 degrees if the cross-sectional shape of the bottle B is an equilateral triangle, and at an angle of 72 degrees if it is a regular pentagon. With this configuration, the article contact portion 28 of each gripping arm 20 can be brought into contact with the side of the article B, so that the article B can be centered well and held while preventing rotation in the circumferential direction.

[0047] In this embodiment, since the article contact portion 28 that contacts the container B is formed in a curved surface shape (approximately semi-cylindrical shape) that is convex outward, it is possible to make curved surface contact regardless of the size of the container B, and as a result it is possible to suppress damage and breakage of the container B due to contact with the article contact portion 28.

[0048] In this embodiment, the main body portion 27 of the second extension portion 26 is connected to the first extension portion 21 at an inclination toward the first free end 21b. Therefore, when the four gripping arms 20 are in a proximity position, it is possible to bring the article contact portions 28 closer together. Consequently, even if the container B is formed in a rectangular cross-section as in this embodiment, its short side can be gripped well, and even if it is formed in a cylindrical shape with a relatively small diameter, for example, the container B can be securely gripped from all four sides around it.

[0049] Furthermore, it is preferable that the spring constants of the four biasing members 30 attached between adjacent gripping arms 20 are approximately the same. With this configuration, when the four gripping arms 20 move toward the approaching position, the container B can be pressed with equal force from all four sides, thereby further improving the centering accuracy of the container B. Here, "approximately the same" means that the spring constants of the four biasing members 30 are the same, or that they are approximated to the extent that they can be considered to be roughly the same.

[0050] In this embodiment, the biasing member 30, which is a tension spring, is attached between adjacent gripping arms 20, 20 (see Figure 6(a)), but it is also possible to attach it in other ways. For example, as shown in Figure 6(b), a biasing member mounting portion 19 for attaching the biasing member 30 is provided protruding from the lower surface of the upper member 16, and the four biasing members 30 can be attached so as to span between each gripping arm 20 and the biasing member mounting portion 19. With this configuration, the biasing member 30 can be shortened, and the pressing force of the article contact portion 28 against the container B can be controlled for each gripping arm 20. Also, as shown in Figure 6(c), the biasing member 30 can be attached by spanning it between opposing gripping arms 20, 20. With this configuration, the number of biasing members 30 can be reduced.

[0051] In this embodiment, the process is configured to perform the external force application step, the article placement step, and the external force release step in order, followed by post-processing such as filling with the internal liquid, attaching the cap, labeling, and printing. The container B placed on the placement surface 17 is held in a centered state by the four gripping arms 20, which allows the above-mentioned post-processing to be carried out smoothly.

[0052] In this embodiment, after the post-processing described above, a removal process is performed to remove the container B from the article gripping device 1. For example, this removal process can be carried out by moving the article B upward using a known transport means such as a robot. The removal process may be performed in the state after the external force application process described above, that is, when the gripping arm 20 has been moved from the approach position to the release position by positioning the retractable member R to the protruding position P1, or it may be performed while the article B is being gripped by the gripping arm 20. In this embodiment, since the article contact portion 28 has a curved surface shape, even if the article B is removed while being gripped by the gripping arm 20, the container B will not be damaged or broken.

[0053] [Second Embodiment] In the above embodiment (hereinafter referred to as the "first embodiment"), the gripping arm 20 is moved using a reciprocating member R that moves up and down, but in the second embodiment, the gripping arm 120 is moved using a pair of reciprocating members R2 that move horizontally. The article gripping device 101 according to the second embodiment will be described below with reference to Figures 7 to 10. In the following description, only configurations that differ from the first embodiment will be described, and similar configurations will be denoted by the same reference numerals and omitted from description unless necessary. Also, in Figures 7 to 10, the biasing member 30 is omitted for the sake of explanation, but as in the first embodiment, the biasing member 30 is attached to the second extension portion 26 (see Figure 6, etc.), and the gripping arm 20 is biased toward the approach position by the biasing member 30.

[0054] As shown in Figures 7 and 8, the article gripping device 101 according to the second embodiment is placed on the conveying surface of the conveyor C2 (see Figures 9 and 10) and comprises four gripping arms 120. Each gripping arm 120 has a first extension portion 121 and a second extension portion 126. The first extension portion 121 is formed in a roughly comma-shaped form with a rectangular cross-section and has a fixed end 121a, a first free end 121b on the opposite side, and a support portion 121c that supports the second extension portion 126 so that it can swivel. The fixed end 121a is rotatably supported by a shaft portion (not shown) that protrudes from the upper surface of the lower member 11. The shaft portion is provided on the side portion 11b of the lower member 11, with two shafts protruding from near the center of each of the opposing pair of sides.

[0055] The first free end 121b has a curved surface on its side. As will be described in detail later, in this embodiment, the first free end 121b is moved toward the inside in the width direction of the article gripping device 101 by a horizontally movable reciprocating member R2. That is, in the second embodiment, the pressing force applied by the reciprocating member R2 to press the first free end 121b toward the inside in the width direction of the article gripping device 101 is the external force, and the first free end 121b is the part to which the external force is applied when pressed by the reciprocating member R2. The support portion 121c has a substantially hemispherical concave shape into which the connecting end 127a of the second extension portion 126, which will be described later, can be inserted, and is formed on the upper surface on the side of the first free end 121b.

[0056] The second extension portion 126 is composed of a main body portion 127 having a rod shape with a rectangular cross-section. The main body 127 has a connecting end 127a connected to the support portion 121c of the first extension portion 121, a second free end 127b on the opposite side, and a protruding piece 127c. The connecting end 127a is spherical in shape and is enclosed within the support portion 121c of the first extension portion 121. The second extension portion 126 is supported by the first extension portion 121 so as to be able to swivel, with the connecting end 127a enclosed within the support portion 121c.

[0057] Similar to the first embodiment, an article contact portion 28 is connected to the second free end 127b. The protruding piece 127c protrudes from the side surface between the connecting end 127a and the second free end 127b in the direction in which the curved surface 28a of the article contact portion 28 is formed, and has a hole (not shown) through which the shaft member 141 can be inserted. The protruding piece 127c is rotatably supported by a protruding piece 119 that protrudes from the lower surface of the upper member 16, so as to allow the shaft member 141 to pass through. In other words, in the second embodiment, the second extension portion 126 is swivelably supported by the first extension portion 121 and rotatably supported by the upper member 16.

[0058] The gripping arm 120 is biased toward the approaching position by the biasing member 30 (see Figure 6, etc.), similar to the first embodiment. In this state, the first free ends 121b of adjacent first extensions 121 are close to each other without interfering with each other and are positioned near the edge 11a of the lower member 11 (see Figure 7). That is, in Figure 7, the tip of the reciprocating member R2 is shown near the first free end 121b, but the reciprocating member R2 is not pressing against the first free end 121b.

[0059] The gripping arm 120 moves from the approach position (see Figure 7) to the release position (see Figure 8) by pressing the first free end 121b of the first extension portion 121 toward the inside in the width direction of the article gripping device 101. When the first free end 121b is pressed, the first extension portion 121 rotates around the fixed end 121a, and the connecting end 127a of the second extension portion 126, which is enclosed by the first free end 121b, also moves toward the inside in the width direction of the article gripping device 101. In other words, in the second embodiment, the gripping arm 120 is configured to move from the approach position to the release position by the pressing force of the reciprocating portion member R2 acting on the first free end 121b, which acts as an external force application portion. Since the second extension portion 126 is rotatably supported on the upper member 16 via the protruding piece 127c, when the connecting end 127a moves inward in the width direction of the article gripping device 101, the article contact portion 28 connected to the second free end 127b moves toward the edge portion 16a of the upper member 16. As a result, the four gripping arms 120 are positioned in the released position, resisting the biasing force of the biasing member 30.

[0060] On the other hand, the movement of the gripping arm 120 from the release position to the approach position is performed by releasing the inward pressure in the width direction of the article gripping device 101 on the first free end 121b side. As a result, the four gripping arms 120 move toward the release position in the opposite direction to the movement when moving toward the release position described above, due to the biasing force of the biasing member 30.

[0061] As shown in Figures 9 and 10, in this embodiment, the plate-shaped retractable members R2 are arranged to face each other across the conveyor C2 (a pair of conveyor guides CG, CG). The retractable members R2 are members for pressing adjacent first free ends 121b, 121b toward the inside in the width direction of the article gripping device 101. The pair of retractable members R2, R2 are configured to move back and forth between a protruding position P1' located on the conveying surface of the conveyor C2 and a non-protruding position P2' outside the conveying surface. The pair of retractable members R2, R2 are configured to perform the same operation (i.e., mirror image operation with respect to the centerline of the conveyor C2) when driven by a drive source such as a motor or air cylinder. It is preferable to use an air cylinder as the drive source from the viewpoint of simplifying the structure. When the retractable member R2 moves to the protruding position P1', it simultaneously presses adjacent first free ends 121b, 121b toward the inside in the width direction of the article gripping device 101, while when it moves to the non-protruding position P2', it releases the pressure on adjacent first free ends 121b, 121b. The reciprocating member R2 is formed so that its tip tapers gently towards the center in the width direction. Therefore, when the reciprocating member R2 moves toward the protruding position P1', it is possible to smoothly press the adjacent first free ends 121b, 121b.

[0062] Next, the operation of the article gripping device 101 will be explained with reference to Figures 9 and 10. Figure 9 shows a schematic plan view of the production line for bottle-shaped products, and Figure 10 shows a schematic cross-sectional view taken along the line AA in Figure 9. As shown in Figures 9 and 10, in the second embodiment, similar to the first embodiment, when the article gripping device 101 is transported by the conveyor C2 to the position where the retractable members R2 are positioned, the transport operation is temporarily stopped, and the pair of retractable members R2 move from the non-protruding position P2' to the protruding position P1'. As a result, adjacent first free ends 121b, 121b are simultaneously pressed inward in the width direction of the article gripping device 101, and the four gripping arms 120 move from the approach position to the release position against the biasing force of the biasing member 30 (external force application step, see Figure 8).

[0063] In this state, in this embodiment, the container B is placed on the mounting surface 17 (article mounting step), and then the pair of retractable members R2, R2 are configured to move from the protruding position P1' to the non-protruding position P2', respectively. As a result, the four gripping arms 120 are moved from the release position to the approaching position by the biasing force of the biasing member 30, and the container B is gripped in a centered state by each article contact portion 28 (external force release step).

[0064] In the second embodiment, after the external force application step, the article placement step, and the external force release step are performed in order, the conveyor is operated (the article gripping device 101 holding container B is transported) to perform post-processing such as filling with the internal liquid, attaching the cap, labeling, and printing, similar to the first embodiment. After all of these post-processing steps have been completed, container B is removed from the article gripping device 101.

[0065] Thus, in the article gripping device 101 according to the second embodiment, the article contact portion 28 is configured to operate by a pair of horizontally moving forward and backward members R2. Therefore, unlike the first embodiment, it can be used on conveyors such as belt conveyors and top chain conveyors with continuous conveying surfaces. As a result, the article gripping device 101 according to the second embodiment can be made highly versatile.

[0066] In the second embodiment, the container B is gripped by four gripping arms 120, but the number of arms can be changed as appropriate, as long as it is three or more, as in the first embodiment. In this case, if the number of gripping arms 120 is odd, the number of retractable members R2 that press against the first free end 121b of the first extension 121 should be provided in proportion to the number of gripping arms 120. For example, if there are three gripping arms 120, there should be three retractable members R2, and if there are five gripping arms, there should be five retractable members R2. On the other hand, if the number of gripping arms is even, for example six, as in the second embodiment, provided that the first free ends 121b of each adjacent first extension 121 are positioned close to each other, it is possible to use half the number of retractable members R2, for example, if there are six gripping arms 120, there should be three retractable members R2.

[0067] In the above embodiments, a tension spring was used as the biasing member 30, but other biasing members such as torsion springs can be used. Although the present invention has been described above based on preferred embodiments, etc., the present invention is not limited to the embodiments and modifications described above. [Explanation of symbols]

[0068] 1,101 Article gripping device 10 bases 11 Lower section member 11a Edge 12 Support part 12a Projection piece 12b Hole 13 Opening 16 Upper component (plate) 16a Edge 17 Mounting surface 18 Hole 19. Mounting part for biasing member 119 Projecting piece 20,120 gripping arms 21,121 1st extension part 21a,121a Fixed end 21b, 121b 1st free end (external force application part) 21c slope 121c Support part 26,126 2nd extension part 27,127 Main body 27a, 127a connection terminals 27b,127b 2nd free end 127c protruding piece 28 Article contact part 28a Curved surface 29. Mounting part for biasing member 29a Shaft 30 biasing member 40 Support member 41,141 Shaft members B container S storage space R, R2 Advance / retract member P1,P1´ protrusion position P2,P2´ Non-protruding position C,C2 Conveyor CG Conveyor Guide θ angle

Claims

1. An article gripping device comprising a base having an article placement portion and three or more gripping arms arranged around the placement portion, each of the gripping arms is rotatably supported on the base and has an article contact portion at one end thereof that is capable of contacting an article placed on the placement portion; An article gripping device, wherein each of the gripping arms rotates to move between a close position in which the article contact portions are close to each other and a released position in which the article contact portions are separated from each other, the article contact portions are biased in a direction from the released position toward the close position by a biasing member, and the device has an external force application portion provided on the end side opposite the one end side and capable of applying an external force against the biasing force of the biasing member.

2. The base is a plate having the placement portion on an upper surface thereof; a housing space located below the plate and housing the biasing member; The article gripping device according to claim 1 , wherein the gripping arm is rotatably supported by the base on an outer periphery side of the storage space and protrudes upward beyond the placement portion.

3. The gripping arm includes: a first extension portion having a fixed end rotatably supported on the base and a first free end opposite the fixed end; a second extension portion having a connection end connected to the first extension portion and a second free end opposite the connection end, the first extension portion has the external force application portion on the first free end side, The article gripping device according to claim 2 , wherein the second extension portion has the article contact portion on the second free end side.

4. 4. The article gripping device according to claim 1, wherein the biasing member is a tension spring and is bridged between adjacent gripping arms.

5. An article gripping method using the article gripping device according to any one of claims 1 to 3, an external force application step of applying an external force to the external force application unit to move the plurality of gripping arms from the approach position to the release position; an article placement step of placing an article on the placement section after the external force application step; an external force releasing process for releasing the external force applied to the external force application section after the item placing process, thereby moving the gripping arm from the release position toward the approach position and bringing the item contact section into contact with the item.

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