JP7521764B2 - Robot Hand - Google Patents

Description

The present invention relates to a robot hand, and in particular to a robot hand for grasping an object.

In ready-meal factories that manufacture ready-meal items such as boxed lunches, pre-cooked meals, and prepared dishes, the task of placing cooked foods into food containers used to be done entirely by hand by workers. However, due to recent labor shortages and rising labor costs, robots specialized in plating food have been developed to replace this manual work by workers.

JP 2022-15985 A

Conventional robotic hands for gripping food are heavy because they contain metal parts, and it takes time to deform and control the hand, making it difficult to grip and release food quickly (see, for example, Patent Document 1). In addition, rust-preventive oil, lubricating oil, etc. are applied to the metal parts, and detergent that matches the oil must be used when cleaning, and oil must be applied again after cleaning. Furthermore, if the metal parts rust, the rust must be removed and the parts must be replaced, resulting in a high workload.

In addition, conventional robotic hands that contain metal parts are hard and heavy, making it difficult to provide passive safety features; for example, accidents could occur when the robotic hand comes into contact with a worker.

In consideration of the above problems, the present invention aims to provide a robot hand that is highly safe, capable of high-speed gripping and releasing operations, and reduces the workload during cleaning.

The first aspect of the present invention is a robot hand comprising two or more claws for gripping an object, finger portions having the same number as the number of claws connected to each of the two or more claws, the finger portions being rotatably connected to each other by links, and bellows having the same number as the number of finger portions connected to the finger portions, the bellows being connected to an air pressure control system, and the air pressure inside the bellows being controlled by the air pressure control system to control the length of the bellows, thereby controlling the distance between the finger portions and allowing the claws to grip an object.

In a first aspect of the present invention, the claw may have two protrusions at a position where the claw is connected to the finger portion, and the two protrusions may be fixed to two receiving holes provided in the finger portion, thereby connecting the claw to the finger portion.

In the first aspect of the present invention, the smallest distance between the fingers may be greater than the size of the article.

In a first aspect of the present invention, at least some of the components constituting the robot hand may be made of a resin that is destroyed by an external force exceeding a predetermined value, and the components may be preferentially destroyed by an overload on the robot hand.

In the first aspect of the present invention, the bellows may have connecting parts at both ends, each of which has a groove into which an end of the bellows fits , and a packing may be provided between the connecting parts connected to the air pressure control system and the bellows.

In the first aspect of the present invention, the robot may further include a bayonet ring and a mounting flange connected to a pneumatic control system, and the mounting flange and the robot hand may be fixed to each other by contacting the mounting flange with the robot hand and rotating the bayonet ring.

In a first aspect of the present invention, the bayonet ring has an engagement groove having an engagement groove convex portion, and the robot hand has an external claw having a claw recess, and when the bayonet ring is rotated, the engagement groove slides relative to the external claw, and the engagement groove convex portion and the claw recess engage with each other to fix the mounting flange and the robot hand.

In a first aspect of the present invention, the robot hand may include an elastic portion and a protrusion at the tip of the elastic portion, and the bayonet ring may include a receiving hole, and when the bayonet ring is rotated, the protrusion may enter the receiving hole, thereby fixing the mounting flange and the robot hand.

In the first aspect of the present invention, a second packing is further provided, and the second packing is disposed between the mounting flange and the robot hand, and the air joint of the pneumatic control system of the robot hand and the air joint of the pneumatic control system of the mounting flange, and the electrical contacts of the robot hand and the electrical contacts of the mounting flange may be connected at a position where the mounting flange and the robot hand come into contact.

In a first aspect of the present invention, the claw has a gripping portion, and the gripping portion may consist of multiple long claws.

In the first aspect of the present invention, the claw has a gripping portion, and the gripping portion may be cup-shaped.

In the first aspect of the present invention, the claw may have a gripping portion, and the gripping portion may have a pressing plate.

The present invention provides a robot hand that is highly safe, capable of high-speed gripping and releasing operations, and reduces the workload when cleaning.

FIG. 2 is a front view of a robot hand according to an embodiment of the present invention. FIG. 2 is a front cross-sectional view of the robot hand according to the present embodiment. 4 is a cross-sectional view of a bellows part of the robot hand according to the embodiment. FIG. 1 is a cross-sectional view of a tool changer of a robot hand according to the present embodiment. FIG. FIG. 2 is a top view of a tool changer of the robot hand according to the present embodiment. FIG. 6 is a cross-sectional view of the tool changer shown in FIGS. 4 and 5 taken along section A-A'. FIG. 2 is a top view of a tool changer of the robot hand according to the present embodiment. 1 is a bottom view of a tool changer of the robot hand according to the present embodiment. FIG. 1A to 1C are diagrams illustrating an example of use of the robot hand according to the present embodiment. 1A to 1C are diagrams illustrating the safety of a robot hand according to the present embodiment. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. 4 is a cross-sectional view of a connection portion of the robot hand according to the present embodiment. FIG. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. 14A and 14B are diagrams showing the nail of FIG. 13 when attached to a finger part, in which FIG. 14A is a front view and FIG. 14B is a front perspective view. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. FIG. 16 is a bottom perspective view showing the nail of FIG. 15 when attached to a finger portion. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. FIG. 18 is a bottom perspective view showing the nail of FIG. 17 when attached to a finger portion. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. 20A and 20B are diagrams showing the claw of FIG. 19 when attached to a finger portion, in which (a) is the claw with the finger portion closed, (b) is the claw in the stage before gripping an object, and (c) is the claw gripping an object. 1A to 1C are diagrams showing an example of a claw of a robot hand according to the present embodiment, in which (a) is a top view, (b) is a left side view, and (c) is a front view. 22A and 22B are diagrams showing the nail of FIG. 21 attached to a finger part, in which (a) shows the nail before touching the green onion, and (b) shows the nail pressed against the green onion.

Next, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings relating to the embodiment, the same or similar parts are given the same or similar reference numerals. However, the drawings are schematic.

The embodiments are merely examples of devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the configuration, arrangement, layout, etc. of each component to those described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

(Embodiment)
A robot hand according to an embodiment of the present invention will be described below. Fig. 1 shows a front view of a robot hand 1 according to this embodiment. The robot hand 1 shown in Fig. 1 is composed of a tool changer 2, a hand body 3, and a claw portion 4.

The tool changer 2 connects the hand body 3 to a pneumatic control system (not shown). As described below, the tool changer 2 allows the hand body 3 to be easily removed from and attached to the pneumatic control system. This makes it easy to replace, clean, and perform other maintenance on the robot hand.

The hand body 3 has a claw portion 4 connected to its tip, and is connected to an air pressure control system (not shown) by the tool changer 2.

The claw portion 4 is connected to the finger portions 20a and 20b of the hand body 3, and the claw portion 4 grasps and releases an object by operating the hand body 3. In this embodiment, the claw portion 4 is composed of claws 4a and 4b, and the claws 4a and 4b have mirror-symmetric shapes. As described below, the gripping portions 17a and 17b of the claws 4a and 4b have shapes suitable for reliably and easily grasping and releasing an object. The claws 4a and 4b are removable, and claws having gripping portions 17a and 17b shaped according to the type and shape of the object can be attached to the hand body 3 as claws 4a and 4b. The claws 4a and 4b shown in Figures 1 and 2 are an example of claws according to this embodiment.

All parts of the robot hand 1 shown in FIG. 1 are made of resin materials. Conventional robot hands include metal parts, and anti-rust oil and lubricating oil are applied to the metal parts. When cleaning such a robot hand, it is necessary to use a detergent that matches the oil and re-apply oil after cleaning. In addition, if the metal parts rust, it is necessary to remove the rust and replace the parts, which increases the burden of maintenance work. All parts of the robot hand 1 according to this embodiment are made of resin materials, and do not require anti-rust oil or lubricating oil. Compared to robot hands that include metal parts, cleaning is easier and the workload is lower. Examples of resin materials used in the robot hand 1 according to this embodiment include thermoplastic resins such as polyethylene and polypropylene, and fluororesins such as PTFE.

(Hand body)
The hand body 3 is composed of bellows 12a, 12b, a link 14, inner connectors 13a, 13b, outer connectors 18a, 18b, finger portions 20a, 20b, upper finger portions 25a, 25b, and a shaft portion 19.

Figure 2 shows a front cross-sectional view of the robot hand 1 according to this embodiment. The robot hand 1 shown in Figure 1 is in a state in which the claws 4a and 4b are in contact with each other, and the finger portions 20a and 20b are closest to each other. This state will be referred to below as the finger portions 20a and 20b being closed. The robot hand 1 shown in Figure 2 is in a state in which the claws 4a and 4b are separated from each other, and the finger portions 20a and 20b are spaced apart. This state will be referred to below as the finger portions 20a and 20b being open.

The robot hand 1 shown in Figures 1 and 2 has a mirror-symmetric structure on the paper, except for the link 14, and the bellows 12a, inner connector 13a, outer connector 18a, finger 20a, and upper finger 25a of the hand body 3 are mirror-symmetric in terms of their relative positions relative to the bellows 12b, inner connector 13b, outer connector 18b, finger 20b, and upper finger 25b. The bellows 12a is connected to the shaft 19 via the inner connector 13a, and is connected to the upper finger 25a via the outer connector 18a. The upper finger 25a is continuous from the upper end of the finger 20a. The link 14 is disposed at the lower end of the shaft 19. The finger 20a and the finger 20b are connected to each other by the link 14, and the finger 20a and the finger 20b can rotate relative to each other around the link 14. The internal piping 10 is arranged inside the shaft portion 19, and the bellows 12a, 12b and the internal piping 10 are connected at the inner connection portions 13a, 13b, respectively.

The internal pipe 10 is connected to an air pressure control system (not shown), and the air pressure inside the internal pipe 10 is controlled to be either positive pressure or negative pressure by turning on/off the solenoid valve of the air pressure control system. As will be described later, as shown in FIG. 3, the bellows 12a has a hollow structure, and the hollow part of the internal pipe 10 is continuous with the space 22a which is the hollow part of the bellows 12a. As a result, the air pressure inside the internal pipe 10 is controlled, and at the same time, the air pressure inside the bellows 12a is also controlled. As with the bellows 12a, the air pressure inside the internal pipe 10 is controlled, and at the same time, the air pressure inside the bellows 12b is also controlled.

The bellows 12a and 12b are made of a highly flexible resin material. As a result, when the air pressure inside the bellows 12a and 12b becomes positive, the lengths of the bellows 12a and 12b, i.e., the distance between the inner connecting part 13a and the outer connecting part 18a and the distance between the inner connecting part 13b and the outer connecting part 18b, become longer, and the finger parts 20a and 20b are closed around the link 14 as shown in FIG. 1. When the air pressure inside the bellows 12a and 12b becomes negative, the lengths of the bellows 12a and 12b become shorter, and the finger parts 20a and 20b are open as shown in FIG. 2. The opening and closing of the fingers 20a and 20b allows the claw part 4 to grip and release an object.

Because the finger portion 20a and the finger portion 20b are connected by the link 14, the angle between the bellows 12a, 12b and the shaft portion 19 when the air pressure inside the bellows 12a, 12b is negative and the length of the bellows 12a, 12b is short as shown in Fig. 2 is different from the angle between the bellows 12a, 12b and the shaft portion 19 when the air pressure inside the bellows 12a, 12b is positive and the length of the bellows 12a, 12b is long as shown in Fig. 1. When the mechanism for opening and closing the fingers is made of metal parts as in conventional robot hands, the angle between the air cylinder and the lever chuck changes as the fingers open and close, so a sliding part and a link structure are required, and therefore the mechanism for opening and closing the fingers has a complex structure. The bellows 12a and 12b of the robot hand 1 according to this embodiment are made of a highly flexible resin material, and therefore easily deform from the shape shown in FIG. 2 to the shape shown in FIG. 1 in response to the air pressure inside the bellows 12a and 12b. This simplifies the structure of the mechanism for opening and closing the fingers, making manufacturing and maintenance easier.

In addition, in conventional robot hands that include metal parts, the piping for the air cylinder is placed outside the robot hand structure, and the air tubes that are installed therein restrict the movement of the robot hand. With the robot hand 1 of this embodiment, the piping is placed inside the robot hand 1, so the piping does not restrict the movement of the robot hand 1.

Furthermore, all parts of the robot hand 1 are made of resin material, and it is extremely lightweight compared to conventional robot hands that include metal parts. In conventional robot hands that include metal parts, deformation of the hand due to sliding parts and link structures associated with gripping and releasing an object takes time due to the complex mechanism, but in the robot hand 1 according to this embodiment, there is only one rotating part, the link 14, and because of the simple structure of the bellows 12a, 12b, deformation does not take time. Therefore, compared to the opening and closing movements of the fingers of a conventional robot hand that includes metal parts, the opening and closing movements of the fingers 20a, 20b respond quickly to the on/off of the solenoid valves of the air pressure control system.

The bellows 12a, the inner connecting portion 13a, and the outer connecting portion 18a may be fastened together using an adhesive, or may be fastened together by a fitting structure in which the bellows 12a is fitted into the grooves 23a and 24a without using adhesive, but is not limited to these methods. In this embodiment, a method using a fitting structure is shown as an example of a method for fastening the bellows 12a, the inner connecting portion 13a, and the outer connecting portion 18a.

Figure 3 is a cross-sectional view of the bellows 12a, the inner connecting part 13a, and the outer connecting part 18a. The inner connecting part 13a and the outer connecting part 18a have grooves 23a and 24a, respectively. The end of the bellows 12a is fitted into the groove 23a from the front side of the paper in Figure 3, and the bellows 12a is slid, thereby fastening the bellows 12a and the inner connecting part 13a. When fastening the bellows 12a and the outer connecting part 18a, the end of the bellows 12a is fitted into the groove 24a and the bellows 12a is slid, just as when fastening the bellows 12a and the inner connecting part 13a.

As mentioned above, the hollow portion of the internal pipe 10 and the space 22a, which is the hollow portion of the bellows 12a, are continuous, and the air pressure in the space 22a is controlled by turning on/off the solenoid valve of the air pressure control system connected to the internal pipe 10. To increase the airtightness of the space 22a, a packing may be used between the bellows 12a and the inner connecting part 13a. In this embodiment, an example in which a packing is used is shown. An annular rubber or resin packing 21a is installed at the connection between the bellows 12a and the inner connecting part 13a to prevent air from leaking from the space 22a to the outside of the bellows 12a.

When a robot hand used in a food handling environment contains plastic parts, there are manufacturing risks, such as the limited variety of food-compatible adhesives and their difficulty in obtaining them, and the fact that the use of adhesives is not recommended in high temperature and high humidity environments. Fastening these parts using a fitting structure has the advantage of reducing the above-mentioned risks. Using bellows and packing that are food-compatible and easily available reduces manufacturing risks and enables use in a variety of environments.

The configurations of the bellows 12b, the inner connecting part 13b, and the outer connecting part 18b are the same as those of the bellows 12a, the inner connecting part 13a, and the outer connecting part 18a shown in FIG. 3, except that they are mirror images.

As shown in Figures 1 and 2, the robot hand according to this embodiment has two fingers 20a, 20b, but the number of fingers 20a, 20b is not limited to two and may be three or more. Even when the number of fingers is three or more, the robot hand has the same number of bellows, inner connectors, and outer connectors as the number of fingers. Each finger is connected to the shaft by one or more links, and is further connected to the bellows via the outer connector. The bellows connected to each finger is connected to the shaft via the inner connector. Even when the number of fingers is three or more, the fingers are opened and closed by controlling the air pressure inside the bellows.

Conventional robot hands made of metal parts have a complex mechanism for opening and closing the fingers, and therefore have many problems when they have three or more fingers, such as the weight and volume of the robot hand becoming heavy. With the robot hand of the present invention, the mechanism for changing the fingers is a simple structure, so that a robot hand with three or more fingers is easier to manufacture and maintain than a conventional robot hand.

(Tool Changer)
The tool changer 2 will now be described. Fig. 4 is a cross-sectional view of the tool changer 2, and Fig. 5 is a top view of the tool changer 2 shown in Fig. 4. The tool changer 2 shown in Figs. 4 and 5 is composed of a robot hand body 56, a bayonet ring 55, an attachment flange 53, and a packing 57.

The internal piping 10 is arranged in the center of the robot hand body 56 and the air joint 52. The air joint 52 and the mounting flange 53 are fixed to each other and cannot be removed. The bayonet ring 55 is rotatable relative to the mounting flange 53. When removing the hand body 3 from the pneumatic control system, the bayonet ring 55 is rotated to remove the robot hand body 56 from the mounting flange 53.

The mounting flange 53 is fixed to the air joint 52, and even if the bayonet ring 55 is rotated, the mounting flange 53 does not rotate relative to the air joint 52. Furthermore, when attaching or detaching the robot hand body 56 to or from the mounting flange 53, only the bayonet ring 55 is rotated relative to the mounting flange 53, and the robot hand body 56 is not rotated.

Conventionally, when attaching a robot hand to a flange, a rotary fastening mechanism between the flange and the robot hand was generally used. In other words, the fastening mechanism was located in the center of the flange and the robot hand, and the robot hand was rotated relative to the flange to fasten them. With this mechanism, the air joint and electrical contacts on the robot hand rotate in accordance with the rotation of the robot hand relative to the flange, causing the air joints and electrical contacts on the flange and the robot hand to separate from each other. In addition, because the fastening mechanism was located in the center of the flange and the robot hand, it was difficult to secure sufficient space inside the flange and the robot hand to incorporate the air joint and electrical contacts. This meant that the air joint and electrical wiring had to be installed outside the flange and the robot hand, and there was a risk that the air joint and electrical wiring would restrict the movement of the robot.

According to the tool changer 2 of this embodiment, the mounting flange 53 and the robot hand body 56 are not rotated, and only the bayonet ring 55 is rotated to fasten them together, so that sufficient space can be secured in the center of the mounting flange 53 for assembling the air fitting and electrical contacts. In addition, because the mounting flange 53 and the robot hand body 56 are not rotated when fastening, the air pipe contacts do not rub against each other, and the electrical contacts do not separate. This allows the air fitting and electrical contacts to be assembled inside the mounting flange 53 and the robot hand body 56, and does not restrict the movement of the robot.

When attaching a conventional robot hand including metal parts to a flange, it is necessary to use high-strength metal components in the fastening mechanism in order to firmly fasten the robot hand using an airlock, electromagnet, screw structure, or the like. The fastening mechanism of conventional robot hands is large and heavy because of the use of such strong metal components. In contrast, the tool changer 2 according to this embodiment is made entirely of resin material. This makes it possible to make the robot hand according to this embodiment lighter than conventional robot hands. In addition, because the mechanism fastens by rotating only the bayonet ring 55, it can be made smaller.

In the tool changer 2 according to this embodiment, the robot hand body 56 is fastened to the mounting flange 53. The hollow portion of the air joint 52, the hollow portion of the mounting flange 53, and the hollow portion of the robot hand body 56 are continuous, forming the hollow portion of the internal piping 10 shown in FIG. 1. For this reason, a ring-shaped rubber or resin packing 57 is installed at the connection between the mounting flange 53 and the robot hand body 56 to prevent air from leaking from the hollow portion of the internal piping 10 to the outside of the air joint 52.

(Locking mechanism using concave/convex engagement)
The tool changer 2 according to this embodiment has a locking mechanism that allows the user to feel and confirm a clicking sound and feedback (hereinafter referred to as a clicking sensation) like pressing a switch when the tool changer 2 is locked and locked when the bayonet ring 55 is rotated to fasten the robot hand body 56 to the mounting flange 53. As the locking mechanism according to this embodiment, a locking mechanism using a concave-convex engagement will be described below.

Figure 6 shows a cross-sectional view of section A-A' shown in Figures 4 and 5. Figure 7 shows a top view of the robot hand body 56 shown in Figure 4. Figures 6 and 7 show the case where the tool changer 2 according to this embodiment has a locking function by recess-projection fitting. The top view of the robot hand body 56 shown in Figure 7 shows the robot hand body 56 shown in Figure 4 with the mounting flange 53 and bayonet ring 55 removed.

As shown in FIG. 6, the bayonet ring 55 has a fitting groove 79, and the robot hand body 56 shown in FIG. 7 has an external claw 71. When the robot hand body 56 and the mounting flange 53 are fastened, the external claw 71 slides in the fitting groove 79 as the bayonet ring 55 rotates. The bayonet ring 55 has a fitting groove protrusion 122 that has a convex shape inside the fitting groove 79. In addition, the external claw 71 of the robot body has a claw recess 121 that is concave, and a claw tip portion 123 that smoothly slopes from the tip of the external claw 71.

When fastening the robot hand body 56 and the mounting flange 53, as shown in FIG. 5, by rotating the bayonet ring 55 in the tightening direction of arrow B, the mating groove 79 slides in the direction of arrow B relative to the outer claw 71 as shown in FIG. 6. As the mating groove 79 slides in the direction of arrow B, the claw tip 123, which has an inclined tip, overcomes the mating groove protrusion 122, and the mating groove protrusion 122 and the claw recess 121 engage. At this time, a clicking sensation is felt and the robot hand body 56 and the mounting flange 53 are locked.

Conventionally, mechanisms for removing and attaching a robot hand from a robot hand control system have been used to secure the robot hand by tightly tightening a screw-shaped, helical fixing part (see, for example, REP 2019/142709). With such mechanisms, there is no clicking sensation when fastening, making it impossible to confirm that the hand is locked, and there is a risk that the hand will be used without being fastened, or that the fixing part will not stop in the fastening position, resulting in damage due to excessive tightening, etc.

According to the tool changer 2 of this embodiment, the user can confirm that the robot hand body 56 has been fastened to the mounting flange 53 by hearing a clicking sound, and damage, wear, etc. of the parts caused by over-turning the fixed parts can be prevented. In addition, the fitting groove convex portion 122 fits into the claw concave portion 121 and is fixed, so that the robot hand body 56 is fixed without moving relative to the mounting flange 53 after fastening.

(Snap-fit locking mechanism)
Fig. 8 shows a bottom view of the tool changer 2. Fig. 8 shows the tool changer 2 according to this embodiment having a locking function by snap fit. The robot hand body 56 has an elastic part 72 and a protrusion 75 at the tip of the elastic part 72. A gap 74 is provided between the elastic part 72 and the body part 58 of the robot hand body 56, and when pressure is applied to the protrusion 75 in the direction of the body part 58, the elastic part 72 deforms and the protrusion 75 deforms in the direction of the body part 58. A receiving hole 78 is provided on the outer circumferential surface of the bayonet ring 55.

When fastening the robot hand body 56 to the mounting flange 53, the robot hand body 56 is attached to the bayonet ring 55 with the protrusion 75 pressed toward the body part 58. When the bayonet ring 55 is rotated, the protrusion 75 is pushed toward the body part 58 by the bayonet ring 55, and the bayonet ring 55 rotates while the elastic part 72 remains deformed. When the mating hole 78 provided in the bayonet ring 55 moves to the position of the protrusion 75, the protrusion 75 enters the mating hole 78 due to its elasticity and is fixed in place. When the protrusion 75 enters the mating hole 78, a clicking sensation is generated, and the protrusion 75 and the mating hole 78 fit together due to this clicking sensation, allowing the user to feel and confirm that the robot hand body 56 has been fastened to the mounting flange 53.

When the tool changer 2 according to this embodiment has a locking function using a snap fit, the portion of the protrusion 75 that is inserted into the receiving hole 78 and protrudes from the outer peripheral surface of the bayonet ring 55 can be pushed toward the main body 58 with a finger or the like to push it into the inside of the bayonet ring 55, and in this state the bayonet ring 55 can be rotated to remove the robot hand main body 56 from the mounting flange 53.

Figure 9 shows an example of how the robot hand 1 according to this embodiment can be used. The example of use shown in Figure 9 is, as an example, a plating operation in a ready-meal factory, in which cooked foods 81, 82 are placed into food containers 84 that are conveyed along a conveyer belt. In Figure 9, the robot hand 1 is connected to a robot body 85 via a robot arm 86. The robot hand 1 is placed next to a worker 83, and the robot hand 1 and the worker 83 work together to plate the food.

In ready-meal factories, the foods that are plated into containers are very diverse, and changes to the types and amounts of food to be plated are frequent. For these reasons, it is not easy to perform all of the plating work using a robotic arm. Therefore, there may be cases where the robotic arm and workers work in close proximity to each other.

Conventional robot hands combine air cylinders with link mechanisms, and the actuators and sliding link parts are made of hard metal components, making it difficult to provide passive safety features; for example, accidents could occur if the robot hand came into contact with a worker.

The robot hand 1 according to this embodiment is entirely made of resin. The part of the robot hand 1 shown in FIG. 10 surrounded by the dashed line is made of resin with a thickness equal to or less than the thickness at which it will be destroyed when subjected to an external force exceeding a predetermined value, and is structured to be destroyed preferentially due to overload, such as when the robot hand comes into contact with a worker. In this embodiment, the thickness of the resin in the part surrounded by the dashed line in FIG. 10 is set to 5 mm or less. Furthermore, the bellows 12 is made of a highly flexible resin material, and will deform due to overload. With these configurations, the robot hand 1 according to this embodiment can provide a passive safety function, such as preventing accidents from occurring even when the robot hand comes into contact with a worker.

(nail)
The claw portion 4 will now be described. Each of the claws 4a, 4b that constitute the claw portion 4 is connected to the finger portions 20a, 20b of the hand body 3, and the operation of the hand body 3 causes the claw portion 4 to grip and release an object. As described below, when the robot hand 1 according to this embodiment is used in a ready-meal factory, the hand body 3 can be fitted with claws of a shape suitable for the type, shape, etc. of cooked food.

Figure 11 shows the claw 120a according to this embodiment. Figures 11(a), 11(b), and 11(c) are a top view, a left side view, and a front view of the claw 120a, respectively, showing the claw not attached to the finger portions 20a and 20b of the hand body 3. The claw 120a shown in Figure 12 is composed of a connection portion 15a, a support portion 16a, and a gripping portion 17a. The connection portion 15a is a portion that connects the claw 120a to the finger portions 20a and 20b of the hand body 3. The gripping portion 17a is a portion that grips an object. The support portion 16a supports the connection portion 15a and the gripping portion 17a. The gripping portion 17a of the claw 120a shown in Figure 11 is composed of three long claws 123a.

The claw shown in FIG. 11 is one of the two claws of the robot hand 1 shown in FIG. 1. Two claws as shown in FIG. 11 are prepared and attached to the two fingers 20a, 20b of the robot hand 1 shown in FIG. 1, respectively, so that the left side of the claw shown in FIG. 11(c) faces inward. An object is grasped by the gripper 17a by opening and closing the two fingers 20a, 20b of the robot hand 1.

Figure 12 shows a cross-sectional view of the connection part 15a of the robot hand 1 shown in Figure 1, as viewed from the horizontal direction of the page. The support part 16 of the claw 4 is fixed to the finger part 20a of the hand body 3 by the protrusion part 90 of the claw 4a. The hand body 3 is provided with body supports 91, 92, 93, and 94, and between the body supports 91 and 93, there is a gap into which the support 95 fits without any gaps, and between the body supports 91 and 92 and between the body supports 93 and 94, there are gaps through which the protrusion part 90 can pass, and the protrusion part 90 is exposed to the outside of the hand body 3, and there is a receiving hole 96 into which the protrusion part 90 is hooked and fixed by elasticity, forming a structure that does not come off.

When attaching the claw 4a to the finger portion 20a, the support 95 and protrusion 90 of the claw 4a are inserted from below the plane of the paper in FIG. 12 between the main body support 91 and main body support 93 of the hand main body 3, between the main body support 91 and main body support 92, and between the main body support 93 and main body support 94. The protrusion 90 is caught in the receiving hole 96, and the claw 4a is attached to the finger portion 20a. When removing the claw 4a from the finger portion 20a, the protrusion 90 is pushed into the receiving hole 96 with a finger or the like to deform the support 97 and protrusion 90, and the claw 4a is pulled out below the plane of the paper in FIG. 12.

The robot hand 1 shown in FIG. 1 has a gap 79 between the two fingers 20a and 20b. This gap 79 prevents an object from getting caught between the two fingers 20a and 20b.

Figure 13 shows the claw 140a according to this embodiment. Figures 13(a), 13(b), and 13(c) show a top view, a left side view, and a front view of the claw 140a. Compared to the claw 120a shown in Figure 11, the gripping portion 17a of the claw 140a is composed of five long claws 141a.

Figure 14 shows the appearance of the claw portion 4 when the claw 140a is attached to the finger portion 20 of the hand body 3 and the two finger portions 20a, 20b are closed as shown in Figure 1. Figure 14(a) is a front view, and Figure 14(b) is a front perspective view. As shown in Figure 14, an object is grasped by pinching it with the five long claws 141a.

The number of long claws 123a constituting the gripping portion of claw 120a shown in FIG. 11 is three, and the number of long claws 141a constituting the gripping portion of claw 140a shown in FIG. 13 is five, but the number of long claws is not limited to these. In this way, the amount and size of items that can be gripped can be adjusted by the number of long claws constituting gripping portion 17a.

Figure 15 shows the claw 160a according to this embodiment. Figures 15(a), 15(b), and 15(c) show a top view, a left side view, and a front view of the claw 160a. The claws 4a and 4b shown in Figures 1 and 2 are the same as the claw 160a shown in Figure 15.

Figure 16 shows the appearance of the claws 160a when the two fingers 20a, 20b of the hand body 3 are each attached with the claws 160a closed as shown in Figure 1. Figure 16 is a bottom perspective view. As shown in Figure 16, the gripping portion 17a is cup-shaped, and grips an item by pinching it between the two cups.

Figure 17 shows the claw 180a according to this embodiment. Figures 17(a), 17(b), and 17(c) show a bottom view, a left side view, and a front view of the claw 180a. Figure 18 shows the state of the claw 180a when the claw 180a is attached to each of the two finger portions 20a and 20b of the hand body 3 and the two finger portions 20a and 20b are closed as shown in Figure 1. Figure 18 is a bottom perspective view. The width of the cup shape of the gripping portion 17a of the claw 160a shown in Figure 15(b) is different from the width of the cup shape of the gripping portion 17a of the claw 180a shown in Figure 17(b). The amount and size of the items that can be gripped can be adjusted depending on the size and shape of the cup.

Figure 19 shows the claw 200a according to this embodiment. Figures 19(a), 19(b), and 19(c) show a bottom view, a left side view, and a front view of the claw 200a. The gripping portion 17a of the claw 200a shown in Figure 19 is composed of three long claws 201a. Compared to the long claw 121a shown in Figure 11, the long claws 201a are wider in shape and are made of a highly flexible resin material.

Figure 20 shows how an object is actually grasped when claws 200a are attached to each of the two fingers 20a, 20b. Figure 20(a) shows the state in which the fingers 20a, 20b are closed without grasping an object, Figure 20(b) shows the state before the fingers 20a, 20b are opened and grasp the object 110, and Figure 20(c) shows the state in which the fingers 20a, 20b are closed and grasp the object 110.

The object 110 shown in FIG. 20 is, as an example, chopped green onions. Chopped green onions are soft and easily damaged, such as deforming when pinched with strong force. The claw 200a shown in FIG. 20 is made of a highly flexible resin material, so that the claw 200a can bend as shown in FIG. 20(c) to pinch the chopped green onions with a force that does not damage them. In conventional robot hands that include metal parts, a complex control system is required for gripping force control, making high-speed operation difficult. According to the claw 200a of this embodiment, the claw 200a is made of a highly flexible resin material, so that it can grip objects that are easily damaged. In addition, the degree of flexibility and the shape, such as the length, of the claw 200a can be adjusted to accommodate the softness, shape, weight, etc. of the object.

Figure 21 shows the claw 220a according to this embodiment. Figures 21(a), 21(b), and 21(c) show a bottom view, a left side view, and a front view of the claw 220a. The gripping portion 17a of the claw 220a shown in Figure 21 has a pressing plate 111.

Figure 22 shows a diagram for explaining the actual gripping of an object when claws 220a are attached to each of two finger portions 20a, 20b. The object shown in Figures 22(a) and 22(b) is chopped green onions, as an example. Chopped green onions are soft, and when a large amount of chopped green onions are piled up, it is considered that the green onions at the top of the stack retain their shape when chopped and have a low density. The green onions at the bottom of the stack are compressed by the weight of the onions on top and have a high density. The green onions at the middle depth of the stack are considered to have a density between the green onions at the top and the green onions at the bottom. Therefore, the amount of green onions that can be picked varies depending on the timing of picking the stacked onions.

In FIG. 22(a), the pressing plate 111 of the claw 220a is not touching the onions, so the density of the onions is low at the top of the stack. In FIG. 22(b), the pressing plate 111 is pressed against the onions to apply pressure to them, so that the density of the onions at the top becomes similar to the density of the onions at the middle depth.

For bulk piled items such as those shown in Figures 22(a) and 22(b), the use of a pressing plate can smooth out the surface condition and stabilize the amount of gripping.

The claws shown in Figs. 11 to 22 are examples of claws that can be used in the robot hand according to this embodiment, but the claws are not limited to these, and claws of various shapes can be used depending on the shape, size, hardness, etc. of the object. In addition, although there are two fingers 20a, 20b in the robot hand 1 shown in Fig. 1, there may be three or more, and the shape of the claws may change depending on the number of fingers 20a, 20b. Furthermore, all of the claws shown in Figs. 11 to 22 are used by attaching two claws of the same shape, etc. to each of the two fingers 20a, 20b, but the multiple claws attached to each of the multiple fingers of one robot hand do not need to be the same as each other, and depending on the shape, size, hardness, etc. of the object, the multiple claws attached to each of the multiple fingers of one robot hand may be claws of different shapes, etc.

As described above, the robot hand according to this embodiment can provide a robot hand that is highly safe, capable of high-speed gripping and releasing operations, and reduces the workload during cleaning. In this embodiment, the item that the robot hand according to this embodiment grips is cooked food, but this is not limited to this and can also handle items other than food.

The present invention naturally includes various embodiments not described here. Therefore, the technical scope of the present invention is determined only by the invention-specific matters related to the scope of the claims that are appropriate from the above explanation.

1 Robot hand 2 Tool changer 3 Hand body 4 Claw portion 4a, 4b Claw 10 Internal piping 12a, 12b Bellows 13a, 13b Inner connecting portion 14 Link 16a, 16b Support portion 17a, 17b Grip portion 18a, 18b Outer connecting portion 19 Shaft portion 20a, 20b Finger portion 22a Space 23a, 24a Groove 25a, 25b Upper finger portion 52 Air joint 53 Mounting flange 55 Bayonet ring 56 Robot hand body 57 Gasket 58 Body portion 71 Outer claw 72 Elastic portion 74 Gap 75 Protrusion 78 Receiving hole 79 Fitting groove 81, 82 Food 83 Worker 84 Food container 85 Robot body 86 Robot arm 90 Protrusion portion 91, 92, 93, 94 Body support 95 Support 96 Receiving hole 100 Claw 110 Article 111 Pressing plate 120a, 140a, 160a, 180a, 200a, 220a Claw 121 Claw recess 122 Fitting groove protrusion 123 Claw tip 123a, 141a, 121a Long claw

Claims (11)

Two or more jaws for gripping an object;
a number of fingers to which each of the two or more pawls is connected equal to the number of pawls to which it is connected, the fingers being rotatably connected to one another by links;
and a number of bellows equal to the number of the fingers to which the fingers are connected,
the bellows is connected to an air pressure control system, and the air pressure inside the bellows is controlled by the air pressure control system to control the length of the bellows, thereby controlling the distance between the fingers, and the claws grip the article; the claws, the fingers, and the bellows are all made of a resin material;
The robot hand is characterized in that the bellows has connecting parts at both ends, each of the connecting parts having a groove into which an end of the bellows fits , and a gasket is provided between the connecting parts connected to the pneumatic control system and the bellows. The robot hand described in claim 1, characterized in that the claw has two protrusions at a position where it is connected to the finger portion, and the two protrusions are fixed to two receiving holes provided on the finger portion, thereby connecting the claw to the finger portion. The robot hand of claim 1, characterized in that the distance between the fingers when the distance is at its smallest is greater than the size of the object. The robot hand according to claim 1, characterized in that at least some of the components constituting the robot hand are made of a resin that is destroyed by an external force exceeding a predetermined value, and that the components are preferentially destroyed by an overload on the robot hand. The robot hand according to claim 1, further comprising a bayonet ring and a mounting flange connected to the pneumatic control system, and the mounting flange and the robot hand are fixed together by contacting the mounting flange with the robot hand and rotating the bayonet ring. The bayonet ring includes a fitting groove having a fitting groove protrusion,
The robot hand includes an outer claw having a claw recess,
The robot hand according to claim 5, characterized in that, when the bayonet ring is rotated, the mating groove slides relative to the outer claw, and the mating groove convex portion and the claw concave portion engage with each other, thereby fixing the mounting flange and the robot hand. The robot hand includes an elastic portion and a protrusion at a tip of the elastic portion,
The bayonet ring has a receiving hole,
6. The robot hand according to claim 5, wherein when the bayonet ring is rotated, the projection enters the receiving hole, and the mounting flange and the robot hand are fixed together. The robot hand according to claim 5, further comprising a second packing, the second packing being disposed between the mounting flange and the robot hand, and an air joint of the pneumatic control system of the robot hand, an air joint of the pneumatic control system of the mounting flange, and an electrical contact of the robot hand and an electrical contact of the mounting flange are connected at a position where the mounting flange and the robot hand come into contact. The robot hand of claim 1, characterized in that the claw has a gripping portion, the gripping portion being made up of multiple long claws. The robot hand of claim 1, wherein the claw has a gripping portion, and the gripping portion is cup-shaped. The robot hand according to claim 1 , wherein the claws have gripping portions, and the gripping portions have a pressing plate.

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