JP7822003B2 - Grip device and manufacturing method thereof - Google Patents

Description

The present invention relates to a gripping device capable of gripping an object and a method for manufacturing the same.

Conventionally, gripping devices, such as those used in robotic hands, are known to be made of flexible materials and bend using air pressure. For example, Japanese Patent Application Laid-Open No. 61-203287 discloses a robotic hand finger that has a tubular body made of flexible material with a bellows portion on one side wall and a plate-like portion on the opposite side wall, and that bends when the internal pressure is increased (Patent Document 1).

Japanese Unexamined Patent Publication No. 61-203287

However, conventional gripping devices, including the fingers for robotic hands described in Patent Document 1, are made thick enough to withstand the pressure of injecting air into them, enough to bend the fingertips and grip them, without bursting or breaking. This makes them unsuitable for work in tight spaces or for delicate work, and also poses the problem of difficulty in controlling the gripping force.

On the other hand, if the wall thickness is made thin, the strength and durability will decrease, and there is a risk of rupture or breakage, so the internal pressure must be lowered. However, low internal pressure can lead to problems such as reduced gripping force and increased bending due to the container's own weight, making it difficult to grip the object.

The present invention was made to solve these problems, and aims to provide a gripping device and manufacturing method therefor that has improved strength and durability to the point that it can withstand internal pressure that can bend the gripping member even if it is thin, making it possible to work in narrow spaces or perform detailed work.

The gripping device of the present invention is capable of gripping objects, even if the gripping member is thin, by improving its strength and durability to a level that allows it to withstand internal pressure that can bend the gripping member. This solves the problem of working in tight spaces or performing delicate work. The gripping device has a plurality of adjacent protrusions with air chambers inside, and air passages that communicate with each of the air chambers. The gripping member is made of a flexible material, and a skeletal member is sealed in at least a portion of the air chambers and the air passages. When gas is injected into the air passages, the gas flows into the air chambers or the gaps between the inner wall surface of the air chambers and the skeletal member, causing the protrusions to expand and bend.

In addition, as one aspect of the present invention, in order to prevent the gripping member and the skeletal member from adhering to each other and to solve the problem of ensuring that gas flows into the gap between them, the gripping member and the skeletal member may be formed from materials that do not adhere to each other.

Furthermore, as one aspect of the present invention, in order to prevent the gripping member and the skeletal member from adhering to each other and to solve the problem of ensuring that gas flows into the gap between them, an anti-adhesion agent may be applied to the contact surfaces of the gripping member and the skeletal member to prevent them from adhering to each other.

In addition, as one aspect of the present invention, in order to solve the problem of further enhancing the effect of improving strength and durability provided by the skeletal member, the skeletal member may have a shape that fills all of the air chambers and the ventilation channels.

The method for manufacturing a gripping device according to the present invention solves the problem of manufacturing a gripping device that can be used in narrow spaces or for detailed work by improving the strength and durability so that it can withstand internal pressure that can bend a gripping member even if the gripping member is thin. The method includes the following steps: a gripping member forming step in which a gripping member is formed from a flexible material with one side open, and which has multiple adjacent protrusions with air chambers inside and air passages communicating with each of the air chambers; a skeletal member forming step in which a skeletal member can be formed that can be sealed in at least a portion of the air chambers and the air passages; a skeletal member filling step in which a skeletal member is filled in at least a portion of the air chambers and the air passages; and a skeletal member sealing step in which a liquid flexible material is poured into one side of the gripping member filled with the skeletal member and hardened to seal the skeletal member.

In addition, as one aspect of the present invention, in order to prevent the gripping member and the skeletal member from adhering to each other and to solve the problem of ensuring that gas flows into the gap between them, the gripping member and the skeletal member may be formed from materials that do not adhere to each other.

Furthermore, in one aspect of the present invention, in order to solve the problem of preventing adhesion between the gripping member and the skeletal member and ensuring that gas flows into the gap between them, an anti-adhesion agent application process may be included before the skeletal member filling process, in which an anti-adhesion agent is applied to the contact surfaces of the gripping member and the skeletal member to prevent them from adhering to each other.

According to the present invention, strength and durability are improved to the extent that the gripping member can withstand internal pressure that could bend the gripping member, even if the wall thickness is thin, making it possible to work in narrow spaces or perform detailed work.

1 is a perspective view showing an embodiment of a gripping device according to the present invention. 1A is a front view of a gripping member of the present embodiment, FIG. 1B is a side view seen from below the front view, and FIG. 1C is a central cross-sectional view of the front view. 1A to 1D are diagrams showing (a) a gripping member forming step, (b) a skeletal member forming step, (c) a skeletal member filling step, and (d) a skeletal member encapsulating step in the manufacturing method of the gripping device of this embodiment. In the gripping device of this embodiment, (a) a diagram showing the state in which an object is clamped by the gripping members, (b) a schematic diagram of a protrusion into which gas has been pressurized, and (c) a diagram showing the state in which the object is gripped by the gripping members. FIG. 10 is a diagram showing a skeletal member used in Model B of Example 1. FIG. 10 is a diagram showing a simulation result of Example 1. 10A to 10C are diagrams showing skeletal members used in (a) Model C, (b) Model D, and (c) Model E in Example 2. FIG. 10 is a diagram showing a simulation result of model A in Example 2. FIG. 10 is a diagram showing a simulation result of model B in Example 2. FIG. 10 is a diagram showing a simulation result of model C in Example 2. FIG. 10 is a diagram showing a simulation result of model D in Example 2. FIG. 10 is a diagram showing a simulation result of Model E in Example 2.

Below, one embodiment of a gripping device and its manufacturing method according to the present invention will be described with reference to the drawings.

The gripping device 1 of this embodiment is capable of gripping an object, and as shown in FIG. 1, mainly comprises a gripping member 2 that grips the object, a skeletal member 3 that forms the skeleton of the gripping member 2, and a device body 4 to which the gripping member 2 is fixed. Each component will be explained below. Note that, in the present invention, the concept of an object includes all objects that can be gripped, including soft objects such as food and fragile objects.

The gripping member 2 is used to grip an object and is made of a flexible, soft material. In this embodiment, the gripping member 2 has a tapered tip and is formed in a thin, generally flat plate shape, as shown in Figure 2(a). Furthermore, on the outer surface of the gripping member 2, as shown in Figures 2(b) and 2(c), multiple protrusions 21 with air chambers 22 inside are arranged adjacent to each other, as well as air passages 23 communicating with each of the air chambers 22 and gas pressure inlets 24 for injecting gas into these air passages 23. Furthermore, in this embodiment, the gripping member 2 has a deflection prevention portion 25 that prevents deflection when turned sideways.

In this embodiment, as shown in FIG. 2(a), multiple protrusions 21 are formed in a substantially rectangular parallelepiped shape and are arranged in parallel along the longitudinal direction of the gripping member 2 so that the longitudinal directions of the protrusions 21 are perpendicular to each other. With this configuration, as described below, when gas is injected, the tip of the gripping member 2 bends toward the inner surface. However, the shape and arrangement of the protrusions 21 are not limited to the above configuration and can be changed as appropriate.

For example, if the protrusions 21 are arranged in parallel so that their longitudinal directions are parallel to the longitudinal direction of the gripping member 2, the side edges of the gripping member 2 (the upper and lower edges in Figure 2(a)) will curve toward the inner surface. In this way, the gripping member 2 can be curved in the desired direction depending on the orientation and arrangement of adjacent protrusions 21.

The flexible material that constitutes the gripping member 2 is not particularly limited, and may be a thermosetting elastomer such as silicone resin, a thermoplastic elastomer such as thermoplastic polyurethane (TPU), or any flexible material with rubber-like elasticity. However, it is preferable to embed a harder material, such as polylactic acid (PLA), in the deflection prevention section 25.

The skeletal member 3 is sealed inside the gripping member 2 and functions as a skeleton for the gripping member 2. In this embodiment, the skeletal member 3 is formed from a flexible, soft material and has a shape that fills the entire air chamber 22 and air passage 23. However, this configuration is not limited, and as will be described later in Example 2, the skeletal member 3 may have a shape that seals at least a portion of the air chamber 22 and air passage 23. Furthermore, the skeletal member 3 is not limited to a soft material and may be made of a metal material, etc. This makes it possible to adjust the degree of curvature of the gripping member 2.

In addition, in this embodiment, the gripping member 2 and the skeletal member 3 are formed from materials that do not adhere to each other. For example, if the gripping member 2 is made of silicone resin, the skeletal member 3 is made of thermoplastic polyurethane or the like. This prevents the gripping member 2 and the skeletal member 3 from adhering to each other, and creates a gap between them through which gas can flow. However, this configuration is not limited to this, and even if the materials are adhesive to each other, an anti-adhesion agent that prevents adhesion between the gripping member 2 and the skeletal member 3 may be applied to the contact surface between them. This anti-adhesion agent is selected appropriately depending on the materials of the gripping member 2 and the skeletal member 3, and examples include fluorine-based release agents and silicone-based release agents.

The device main body 4 is attached to a moving device (not shown) such as a robot arm, and secures the gripping members 2. In this embodiment, as shown in FIG. 1, the base ends of the pair of gripping members 2 are secured by a fixing plate 41 with the inner surfaces of the pair of gripping members 2 facing each other. In this embodiment, as shown in FIG. 1, the fixing plate 41 has screw holes 42 through which screws for securing the plate to the device main body 4 are passed, and a communication hole 43 that communicates with the gas pressure inlet 24 of the gripping member 2. In addition, as shown in FIG. 1, a mounting plate 44 for placing a gripped object on extends forward from the device main body 4 at a position midway between the gripping members 2.

In this embodiment, two gripping members 2 are provided as a pair, but this configuration is not limited to this and the number may be increased or decreased as appropriate depending on the object. For example, one gripping member 2 may be provided facing a flat plate-like member, and the object may be gripped by pressing the gripping member 2 against the plate-like member. Alternatively, four gripping members 2 may be used to grip the object from four directions.

Next, we will explain the manufacturing method of the gripping device 1 of this embodiment.

When manufacturing the gripping device 1 of this embodiment, the gripping member 2 is first formed (gripping member formation process). Specifically, a liquid flexible material is poured into a mold that resembles the shape of the gripping member 2 and then hardened. As a result, as shown in Figure 3(a), a gripping member 2 is formed that has multiple adjacent protrusions 21 with air chambers 22 inside, air passages 23 that communicate with each of the air chambers 22, and one side of the gripping member 2 is open.

In this embodiment, when the liquid flexible material is poured into the mold, a pair of deflection prevention sections 25, 25 pre-molded from hard resin are set in the mold on both sides of the air passage 23 at the base end of the gripping member 2, as shown in Figure 2(a). This results in the gripping member 2 being formed with the deflection prevention sections 25 embedded in it.

Next, the skeletal member 3 to be enclosed inside the gripping member 2 is formed (skeletal member formation process). In this embodiment, the skeletal member 3 is formed from a material that does not bond to the gripping member 2, and as shown in Figure 3(b), has a shape that fills all of the air chamber 22 and ventilation channel 23. Note that, like the gripping member 2, the skeletal member 3 may be formed using a molding die, or may be shaped using a 3D printer or the like.

Next, the skeletal member 3 is filled into the air chamber 22 and the air passage 23 from the open side of the gripping member 2 (skeletal member filling process). In this embodiment, the skeletal member 3 is filled by fitting a pre-formed skeletal member 3 into the interior of the gripping member 2. As a result, as shown in FIG. 3(c), the skeletal member 3 is filled in a state of tight contact with the inner wall surfaces of the air chamber 22 and the air passage 23 of the gripping member 2. Alternatively, the gripping member 2 formed in the gripping member forming process may be used as a mold, and a liquid flexible material, which is the raw material for the skeletal member 3, may be poured into the mold and hardened to fill the gripping member 2 with the skeletal member 3. In this case, the skeletal member forming process and the skeletal member filling process are performed simultaneously.

Finally, the skeletal member 3 filled inside the gripping member 2 is sealed (skeletal member sealing process). Specifically, as shown in Figure 3(d), a liquid flexible material is poured onto one side of the gripping member 2 filled with the skeletal member 3 and hardened, thereby sealing the skeletal member 3. At this time, the liquid flexible material poured to seal the skeletal member 3 hardens in a state where it does not adhere to the skeletal member 3, but only adheres to the gripping member 2.

This allows gas to flow into the gap between the inner wall surface of the air chamber 22 and the skeletal member 3, and into the gap between the inner wall surface of the ventilation path 23 and the skeletal member 3. Furthermore, the liquid flexible material poured into one side hardens to become one with the gripping member 2, making it less likely to peel off than when bonded with adhesive or the like. Furthermore, as described later in Example 1, incorporating the skeletal member 3 into the air chamber 22 and the ventilation path 23 improves strength and durability, making it possible to inject air at an internal pressure sufficient to bend the gripping member even when the wall thickness is thin.

Next, the operation of the gripping device 1 of this embodiment will be described. Note that the following explanation will be given for the case where the gripping device 1 is attached to a moving device (not shown) such as a robot arm and used.

First, when using the gripping device 1 of this embodiment, as shown in Figure 4(a), the gripping device 1 is moved and positioned so that the pair of gripping members 2, 2 sandwich the object. At this time, each gripping member 2 is formed in a thin, approximately flat plate shape, making it easy to insert into narrow spaces or crowded areas and suitable for fine work. This makes it possible, for example, to grip different types of cut cakes and pack them tightly into small boxes.

In addition, in this embodiment, the framework member 3 and deflection prevention section 25 enclosed inside the gripping member 2 prevent the gripping member 2 from deflecting due to its own weight. This makes it possible to use the gripping member 2 in various orientations depending on the shape of the object and the type of work being performed.

Next, when gas is injected into the air passage 23 through the gas pressure inlet 24 connected to a gas supply tube (not shown), the gas flows into the gap between the inner wall surface of the air chamber 22 and the skeletal member 3, as shown in Figure 4(b), causing each protrusion 21 to expand. As a result, due to interference between adjacent protrusions 21 and differences in the expansion rates between the outer and inner surfaces, the gripping member 2 bends inward and grips the object.

In this embodiment, the skeletal member 3 enclosed inside the gripping member 2 improves the strength and durability of the gripping member 2 to the point that it can withstand internal pressure that can bend the gripping member 2, even if it is thin. As a result, the gripping member 2 will not break even when a higher-pressure gas is injected than before, and the gripping member 2 becomes hard all the way to its tip, improving its gripping force. This makes it easy to grip even heavy or minute objects.

The gripping device 1 and the manufacturing method thereof according to the present embodiment described above provide the following advantages.
1. Even though the thickness is thin, the strength and durability are improved to the extent that the gripping member 2 can withstand the internal pressure that can bend it, making it possible to perform work in narrow spaces or delicate work.
2. The gripping member 2 and the framework member 3 can be prevented from adhering to each other, and gas can be reliably introduced into the gap between them.
3. The effect of improving the strength and durability provided by the frame member 3 can be further enhanced.
4. If the gripping member 2 has a thin wall thickness, it is easy to precisely control the gripping force, and even soft foods can be packed tightly in boxes.
5. It can automate tasks such as grasping, aligning, and boxing of objects, reducing the number of workers required in food factories and other facilities that previously required many manual processes, thereby alleviating labor shortages and improving operating rates.

Next, specific examples of the gripping device 1 and its manufacturing method according to the present invention will be described. Note that the technical scope of the present invention is not limited to the features illustrated by the following examples.

In this Example 1, a simulation was conducted to confirm the extent to which the skeletal member 3 improves the strength and durability of the gripping member 2.

The simulation conditions in this Example 1 are as follows.
・Simulation software: SolidWorks 2011 Simulation
Loading conditions: A pressure of 0.04 MPa is applied to the inside of the gripping member 2.

The model of the gripping member 2 used in the simulation is as follows.
A: Hollow gripping member 2 without skeletal member 3 enclosed
B: A gripping member 2 enclosing a framework member 3 (FIG. 5) shaped to fill the entire air chamber 22 and the air passage 23.

Figure 6 shows the results of a simulation of the stress generated when pressurization was applied inside the gripping member 2 under the above conditions. As shown in Figure 6, in Model A, in which the skeletal member 3 was not enclosed, a large stress of up to approximately 0.05 MPa was generated in the air chamber 22 and the air vent 23, and a heavy load was applied. On the other hand, in Model B, in which the skeletal member 3 was enclosed, only about half the stress of Model A was generated in the air chamber 22 and the air vent 23, and a heavy load was not applied overall.

This Example 1 demonstrates that the strength and durability of the gripping member 2 can be improved by enclosing the skeletal member 3 in the air chamber 22 and ventilation channel 23 of the gripping member 2.

In this Example 2, a simulation was conducted to confirm the extent to which the strength and durability of the gripping member 2 differ depending on the shape of the skeletal member 3.

The simulation conditions in the second embodiment are the same as those in the first embodiment.
The model of the gripping member 2 used in the simulation is as follows.
A: Hollow gripping member 2 without skeletal member 3 enclosed
B: A gripping member 2 enclosing a framework member 3 (FIG. 5) shaped to fill the entire air chamber 22 and the air passage 23.
C: A gripping member 2 in which a framework member 3 (FIG. 7(a)) having a shape that fills only the air passage 23 is enclosed.
D: A gripping member 2 enclosing a framework member 3 (FIG. 7(b)) shaped to fill only the ventilation path 23 and the air chamber 22 in the Z direction of the ventilation path 23.
E: A gripping member 2 enclosing a framework member 3 (FIG. 7(c)) shaped to fill only the ventilation path 23 and the air chamber 22 in the Y direction of the ventilation path 23.

Figures 8 to 12 show the results of a simulation of the amount of displacement when pressurization is applied inside the gripping member 2 under the above conditions. As shown in Figure 8, in Model A, where the skeletal member 3 is not enclosed, the amount of displacement in the air chamber 22 and ventilation path 23 was the largest, at approximately 0.7 to 1.0 mm, making it more susceptible to damage. On the other hand, as shown in Figure 9, in Model B, where the skeletal member 3 is entirely enclosed, the amount of displacement in the air chamber 22 and ventilation path 23 was the smallest, at approximately 0.0 to 0.6 mm, making it less susceptible to damage.

As shown in Figures 10 to 12, in models C to E, in which the skeletal member 3 was partially enclosed, the displacement in the air chamber 22 was approximately 0.5 to 1.0, but overall the displacement was reduced compared to model A, and although not as much as model B, they were less susceptible to breakage.

According to the above-described Example 2, it was demonstrated that the strength and durability of the gripping member 2 can be improved by enclosing the skeletal member 3 in at least a portion of the air chamber 22 and ventilation path 23 of the gripping member 2. Furthermore, it was demonstrated that the effect of improving the strength and durability provided by the skeletal member 3 can be further enhanced by enclosing the skeletal member 3 in a shape that fills the entire air chamber 22 and ventilation path 23 of the gripping member 2.

Note that the gripping device 1 and its manufacturing method according to the present invention are not limited to the above-described embodiment and can be modified as appropriate.

For example, in the above-described embodiment, the pair of gripping members 2, 2 are used with the gripping members facing horizontally, but this configuration is not limited to this. The gripping members 2 may also be used with the gripping members facing downward, as in a crane game.

Furthermore, while the present embodiment described above uses a thin, approximately flat gripping member 2, this configuration is not limited to this. In other words, even if the gripping member 2 is thick, as in existing robot hands, as long as it has a structure similar to that of the present embodiment described above, improvements in strength, durability, and gripping force can be expected.

REFERENCE SIGNS LIST 1 Grip device 2 Grip member 3 Skeleton member 4 Device body 21 Protrusion 22 Air chamber 23 Air passage 24 Gas pressure inlet 25 Deflection prevention portion 41 Fixing plate 42 Screw hole 43 Communication hole 44 Placement plate

Claims (7)

A gripping device capable of gripping an object,
a gripping member formed of a flexible material in a substantially flat plate shape, the gripping member having a plurality of protrusions arranged adjacent to each other and each having an air chamber therein and an air passage communicating with each of the air chambers;
a framework member enclosed in at least a portion of the air chamber and the air passage;
and
the skeletal member is sealed in a state of being in close contact with the inner wall surfaces of the air chamber and the air passage,
When gas is injected into the air passage, the gas flows into the air chamber or into the gap between the inner wall surface of the air chamber and the skeletal member, causing the protrusion to expand and bend. A gripping device capable of gripping an object,
a gripping member made of a flexible material, the gripping member having a plurality of protrusions arranged adjacent to each other and each having an air chamber therein, and an air passage communicating with each of the air chambers;
a framework member enclosed in at least a portion of the air chamber and the air passage;
and
the skeletal member has a shape that fills the entire air chamber and the air passage,
When gas is injected into the air passage, the gas flows into the air chamber or into the gap between the inner wall surface of the air chamber and the skeletal member, causing the protrusion to expand and bend. 3. The gripping device according to claim 1 , wherein the gripping member and the skeletal member are formed of materials that do not adhere to each other. 3. The gripping device according to claim 1 , wherein an anti-adhesion agent is applied to contact surfaces of the gripping member and the framework member to prevent them from adhering to each other. a gripping member forming step of forming a gripping member made of a flexible material with a plurality of protrusions each having an air chamber therein arranged adjacent to one another and with air passages communicating with each of the air chambers, the gripping member having one side open;
a skeleton member forming step of forming a skeleton member capable of sealing at least a portion of the air chamber and the ventilation path;
a skeleton member filling step of filling at least a portion of the air chamber and the ventilation channel with a skeleton member;
a skeleton member encapsulating step of pouring the liquid flexible material into one side surface of the gripping member filled with the skeleton member and hardening the material to encapsulate the skeleton member;
A method for manufacturing a gripping device, comprising: The method for manufacturing a gripping device according to claim 5 , wherein the gripping member and the skeletal member are formed of materials that do not adhere to each other. 6. The method for manufacturing a gripping device according to claim 5 , further comprising, before the skeletal member filling step, applying an anti-adhesion agent to contact surfaces of the gripping member and the skeletal member to prevent them from adhering to each other.