GRASPING DEVICE

A fluid pressure actuator used as the grasping device 1 includes a cylindrical tube that expands and contracts under the pressure of a fluid, and a sleeve having a stretchable structure in which fiber cords oriented in a predetermined direction are woven and that covers an outer peripheral surface of the tube. A tip portion of the fluid pressure actuator is provided with a spoon-shape housing portion, and a partition plate that closes an opening surface of the housing portion when the fluid pressure actuator is non-curved or curved.

TECHNICAL FIELD

The present disclosure relates to a grasping device using a fluid pressure actuator that curves (curls) during contraction.

BACKGROUND ART

Conventionally, a structure (so-called Mckibben type) having a rubber tube that expands and contracts by air pressure and a sleeve that covers the outer peripheral surface of the tube has been widely used as a fluid pressure actuator that expands and contracts the tube using a gas or liquid.

Such a Mckibben type fluid pressure actuator also has a known structure that curves (curls) during contraction (see Patent Literature 1). Specifically, Patent Literature 1 discloses a grasping device for grasping an object (which may be called a workpiece) by using a plurality of such fluid pressure actuators.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, the above-described grasping device using a fluid pressure actuator has the following problems. Specifically, it is difficult to grasp an appropriate amount of an object at one time, and the amount of an object that can be grasped becomes large or small.

Therefore, the following disclosure is made in view of such a situation, and it is an object to provide a grasping device that can grasp an appropriate amount of an object at each time while using a fluid pressure actuator that curves (curls) during contraction.

An embodiment of the present disclosure is a grasping device (For example, grasping device1) using a plurality of fluid pressure actuators (fluid pressure actuator10) that are curved during contraction. The fluid pressure actuators include a tube (tube110) that is cylindrical, and expands and contracts under fluid pressure, and a sleeve (sleeve120) having a stretchable structure in which fiber cords oriented in a predetermined direction are woven and that covers an outer peripheral surface of the tube. A spoon-shaped housing portion (housing portion50) is provided at a tip portion (tip portion300) of each of the fluid pressure actuators, and a partition plate (partition plate30) is provided to close an opening surface (opening surface50a) of the housing portion when the fluid pressure actuator is non-curved or curved.

Effect of the Invention

According to the grasping device described above, an appropriate amount of an object can be grasped each time while using a fluid pressure actuator that curves (curls) during contraction.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the embodiment will be described based on the drawings. The same functions and structures are denoted by the same or similar reference numerals, and the description thereof will be omitted accordingly.

(1) Overall General Configuration of Grasping Device

FIGS.1(a),1(b) and1(c) are perspective views of the grasping device1according to the present embodiment. Specifically,FIG.1(a)is a perspective view of the grasping device1when the fluid pressure actuator10is non-curved.FIG.1(b)is a perspective view of the grasping device1when the fluid pressure actuator10is curved.FIG.1(c)is a perspective view of the grasping device1when one of the fluid pressure actuators10is curved.

FIGS.2(a)to2(d) are side views and bottom views of the grasping device1. Specifically,FIGS.2(a)and2(b) show a side view and a bottom view of the grasping device1(when the fluid pressure actuator10is non-curved (non-contracted)), respectively.FIGS.2(c)and2(d) show a side view and a bottom view of the grasping device1(when the fluid pressure actuator10is curved (contracted)), respectively.

The grasping device1uses a plurality of fluid pressure actuators10(soft actuators that can be curved and have flexibility) that curve (curl) during contraction. The grasping device1can grasp an object (which may be called a workpiece) using a plurality of fluid pressure actuators10. The grasping device1may be used as a robot hand or the like.

The grasping device1includes a shovel unit15, a mounting base20and a partition plate30. The shovel unit15is configured by a fluid pressure actuator10and a housing portion50.

The fluid pressure actuator10is mounted on the mounting base20. Specifically, the proximal end portion200(Not shown inFIGS.1and2, seeFIG.3) of the fluid pressure actuator10is mounted on the mounting base20.

A tip portion300(seeFIG.3) of the fluid pressure actuator10is provided with the spoon-shaped housing portion50. The housing portion50is concave to hold the scooped object by operating (contracting and expanding) the fluid pressure actuator10. The shovel unit15including the housing portion50may be referred to in other similar terms such as cup, bucket, etc.

The partition plate30is provided to partition the plurality of shovel units15. Specifically, the partition plate30has a flat plate shape and is provided between the two shovel units15. That is, the fluid pressure actuator10(shovel unit15) may be provided on both sides of the partition plate30.

The partition plate30is provided so as to close an opening surface50aof the housing portion50when the fluid pressure actuator10is non-curved (non-contracted).

(2) Schematic Configuration of the Fluid Pressure Actuator

FIG.3is a side view of the fluid pressure actuator10according to the present embodiment.FIG.4is a cross-sectional view of the actuator body portion100along the radial direction DR.

The fluid pressure actuator10has the actuator body portion100, the proximal end portion200and the tip portion300.

The actuator body portion100is composed of a tube110and a sleeve120. Fluid flows into the actuator body portion100through a connection port211a.

As a basic characteristic, the actuator body portion100contracts in the axial direction DAXof the actuator body portion100and expands in the radial direction DR due to fluid flow into the tube110. The actuator body portion100expands in the axial direction DAXof the actuator body portion100and contracts in the radial direction DR due to fluid flow out of the tube110. Due to the shape change of the actuator body portion100, the fluid pressure actuator10functions as an actuator.

In the present embodiment, while using a Mckibben type fluid pressure actuator having such basic characteristics, by providing a (may be referred to as regulating or restricting) restricting member150(Not shown inFIG.3, seeFIGS.4,5, etc.) that restricts compression of the axial direction DAX, it can be curved (curled) in an orthogonal direction orthogonal to the axial direction DAX, that is, in the radial direction DR.

The fluid used to drive the fluid pressure actuator10may be either a gas such as air or a liquid such as water or mineral oil, but in particular, the fluid pressure actuator10may have high durability that can withstand hydraulic drive with high pressure applied to the actuator body portion100.

The connection port211ais attached to a drive pressure source for the fluid pressure actuator10, specifically a hose (pipeline) connected to a gas or liquid compressor. The fluid that flows through the connection port211aflows through the passage hole (not shown) into the actuator body portion100, specifically into the tube110.

The tube110is a cylindrical body that expands and contracts under fluid pressure. The tube110is made of an elastic material such as butyl rubber to repeatedly contract and expand under fluid pressure. When the fluid pressure actuator10is hydraulically driven, it is preferable that it be at least one type selected from the group consisting of NBR (nitrile rubber), chloroprene rubber, and epichlorohydrin rubber having high oil resistance.

The sleeve120is cylindrical and covers the outer peripheral surface of the tube110. The sleeve120is a stretchable structure in which fiber cords oriented in a predetermined direction are woven, and a rhombic shape is repeated by crossing the oriented cords. By having such a shape, the sleeve120deforms pantographically and follows the tube110while restricting its contraction and expansion.

As a cord constituting the sleeve120, a fiber cord of an aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET) is preferably used. However, it is not limited to this kind of fiber cord, but may be a cord of a high-strength fiber such as a PBO fiber (polyparaphenylene benzobisoxazole), for example.

In this embodiment, the restricting member150is provided between the tube110and the sleeve120.

The restricting member150is not compressed in the axial direction DAX, and can be deformed only along the radial direction DR (which may be called the deflection direction). That is, the restricting member150resists compression along the axial direction DAXand is deformable in an orthogonal direction (radial direction DR) orthogonal to the axial direction DAX.

In other words, the restricting member150has a characteristic that is difficult to deform along the axial direction DAXand deflects along the radial direction DR. Deformable may be alternatively referred to as curving or curling.

The restricting member150also has a function of restricting (restraining) the expansion of the tube110(and the sleeve120) to the radial direction DR outside at a position on the outer periphery of the tube110where the restricting member150is provided.

In this embodiment, the restricting member150is provided from one end side to the other end side of the axial direction DAXin the space of inside of the sleeve120, specifically, the radial inside of the sleeve120. In this embodiment, the restricting member150is formed by using a leaf spring.

The size of the leaf spring may be selected according to the size of the fluid pressure actuator10, the required generating force, etc., and is not particularly limited. The material of the leaf spring is also not particularly limited, but typically it may be a material that is easy to curve and resistant to compression, such as a metal such as stainless steel. For example, the restricting member150may be formed of a thin sheet of carbon fiber reinforced plastic (CFRP) or the like. Since the CFRP is less likely to undergo plastic deformation than a metal, it is easy for the fluid pressure actuator10to return to its original straight state after curving.

The proximal end portion200is located on the base portion20side. The connection port211adescribed above is formed on the proximal end portion200. The proximal end portion200may include a mechanism for sealing one end portion of the axial direction DAXof the actuator body portion100.

The tip portion300is located on the opposite side of the proximal end portion200on the base portion20side. The tip portion300may be provided with a mechanism for sealing the other end portion of the axial direction DAXof the actuator body portion100.

The sealing mechanism of the actuator body portion100provided in the proximal end portion200and the tip portion300may be similar to, for example, the fluid pressure actuator disclosed in Japanese Patent Laid-Open Publication No. 2021-088999.

(3) Behavior of the Fluid Pressure Actuator10

FIG.5is an explanatory view of the behavior of the fluid pressure actuator10. The fluid pressure actuator10shown inFIG.5is fixed to the proximal end portion200side, and the tip portion300side is freely movable. That is, the proximal end portion200side is a fixed end, and the tip portion300side is a free end.

As described above, when the fluid flows into the fluid pressure actuator10, it attempts to contract in the axial direction DAX, but since the restricting member150is provided, the contraction along the axial direction DAXis restricted (constrained).

That is, the restricting member150formed by a rigid member such as a leaf spring serves as a backbone, and expands in the radial direction DR outside on the opposite side (lower side inFIG.5) to the position on the outer periphery of the tube110and sleeve120where the restricting member150is provided, thereby shortening the dimension of the fluid pressure actuator10in the axial direction DAXand deflecting the fluid pressure actuator10(Specifically, the actuator body portion100) along the direction D1. Note that the direction D1may be called a flexible direction. In order to make it easy to recognize that the fluid pressure actuator10is bent in the direction D1, a mark M (seeFIG.3) may be provided to indicate the position where the restricting member150is provided.

The restricting member150is provided between the rubber made tube110and the sleeve120, resists compression in the axial direction DAX, is deformable along the orthogonal direction (radial direction DR) orthogonal to, and is arranged in a part in the circumferential direction of the actuator body portion100.

That is, when the actuator body portion100(Mckibben) attempts to contract along the axial direction DAXdue to the inflow (pressurization) of fluid into the actuator body portion100, the portion of the restricting member150has high compressive rigidity, and therefore, the portion where the restricting member150is arranged cannot contract. On the other hand, since the portion of the other actuator body portion100attempts to contract, a force in the curving direction along the orthogonal direction (radial direction DR) is generated, and the portion is curved with the restricting member150as the back face.

(4) Operation of the Grasping Device1

FIGS.6(a), (b)and6(c) show an example of operation of the grasping device1. Specifically,FIGS.6(a), (b)and6(c) show an example of operation in which the grasping device1scoops up a granular object W. As shown inFIGS.6(a), (b)and6(c), the grasping device1functions as a robotic hand and may be movably supported by a support portion.

As shown inFIG.6(a), a space is formed between the partition plate30and the housing portion50(Specifically, the opening surface50a) by contracting and curving the fluid pressure actuator10. In such a state that the shovel unit15is opened, the grasping device1is moved to a desired position so that the object W can be scooped. The movement of the grasping device1may be performed manually or by a mechanical method.

As shown inFIG.6(b), when the fluid pressure actuator10is placed in a non-contracting state, the fluid pressure actuator10returns from a curved state to a straight state, the space between the partition plate30and the housing portion50(opening surface50a) disappears, and the object W is held in the housing portion50.

As shown inFIG.6(c), when the space is formed between the partition plate30and the housing portion50by moving the grasping device1to another desired position and contracting and curving the fluid pressure actuator10again, the object W held in the housing50falls.

Although the object W is not particularly limited, for example, the grasping device1can be suitably used for serving various foodstuffs included in a lunch box.

(5) Modified Example

Next, modified example of the grasping device1will be described.FIGS.7(a), (b) and (c)are perspective views of the grasping device1A related to modified example. Specifically,FIG.7(a)is a perspective view of the grasping device1A when the fluid pressure actuator10is not contracted.FIG.7(b)is a perspective view of the grasping device1A when the fluid pressure actuator10is contracted.FIG.7(c)is a perspective view of the grasping device1A when a part of the fluid pressure actuator10is contracted.

FIGS.8(a) to (d)are side views and bottom views of the grasping device1A. Specifically,FIGS.8(a)and8(b) show a side view and a bottom view of the grasping device1A (when the fluid pressure actuator10is not contracted), respectively.FIGS.8(c)and8(d) show a side view and a bottom view of the grasping device1A (when the fluid pressure actuator10is contracted), respectively.

In the grasping device1A, the partition plate30A has a cross shape in the bottom view of the grasping device1A. Four shovel units15composed of a fluid pressure actuator10and a housing portion50are provided.

The fluid pressure actuator10(shovel unit15) is provided in each of four spaces partitioned by a partition plate30A. Note that the partition plate may not have a cross shape, but may form a plurality of spaces (For example, three or five), and the fluid pressure actuator10may be provided in each of the plurality of spaces partitioned by the partition plate.

Each of the fluid pressure actuators10can operate (contract and expand) individually. Therefore, the grasping device1A can handle a larger amount of the object W of a predetermined unit amount in one operation cycle (from scooping to releasing the object W) compared with the grasping device1. Specifically, the grasping device1can handle two units of the object W because it has two shovel units15, while the grasping device1A can handle four units of the object W because it has four shovel units15.

(6) Function and Effects

According to the above-described embodiment, the following action effects can be obtained. For example, according to the grasping device1, the tip portion300of the fluid pressure actuator10is provided with the spoon-shaped housing portion50, and the partition plate30for closing the opening surface50aof the housing portion50when the fluid pressure actuator10is non-curved (non-contracted).

Therefore, the scooped object W does not spill out, and the object W to be determined is generally held in the housing portion50. That is, the shovel unit15can more reliably grasp (hold) an appropriate amount of the object W at a time.

That is, the grasping device1(and the grasping device1A) can grasp (hold) an appropriate amount of the object at each time while using a fluid pressure actuator that curves (curls) during contraction.

The fluid pressure actuator10(shovel unit15) may be provided on both sides of the partition plate30. Therefore, in one operation cycle (from the scooping up to the releasing the object W), a predetermined unit amount of the object W can be handled more.

In addition, in the grasping device1A, the partition plate30A has a cross shape in the bottom view of the grasping device1A, and four shovel units15are provided. Therefore, a predetermined unit amount of the object W can be handled more in one operation cycle (from scooping to releasing the object W).

(7) Other Embodiments

Although the embodiments have been described above, they are not limited to the description of the embodiments, and it is obvious to those skilled in the art that various modifications and improvements can be made.

For example, an additional partition plate may be provided on the upper surface side of the housing portion50to make the amount of the object W held by the housing portion50more accurate. In the above-described embodiment, the partition plate30may be provided to close the opening surface50aof the housing portion50when the fluid pressure actuator10is non-curved (non-contracted), but may close the opening surface50aof the housing portion50when the fluid pressure actuator10is curved.

In the grasping device1and the grasping device1A, a plurality of shovel units15are provided, but the shovel unit15may be one.

In the above-described embodiment, the flexibility of the fluid pressure actuator is ensured using the restricting member150, but the flexibility of the fluid pressure actuator may be ensured by another structure. For example, by providing a flexible frame material having a part of a bellows shape around the fluid pressure actuator, when the fluid pressure actuator contracts, the fluid pressure actuator is curved such that the bellows portion faces toward an inside.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure may be implemented in a modified and modified manner without departing from the object and scope of the present disclosure as determined by the description of the scope of claims. Accordingly, the description of the present disclosure is for illustrative purposes and does not have any restrictive meaning to the present disclosure.

REFERENCE SIGNS LIST