JPS6246554Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention relates to a robotic hand.
The present invention relates to a robot hand having a pair of opposing grip claws.

[Conventional technology]

Conventionally, there is a robot hand that has a pair of grip claws, each of which is moved toward or away from each other by a fluid cylinder. In the hand, the article is held by bringing the pair of grip claws close to each other, and the article is released from the held state by moving the grip claws away from each other.

[Problem that the invention aims to solve]

For example, when the above-mentioned robot hand picks up articles being transferred on a conveyor and transfers them onto a pallet at another location, the articles on the pallet must be kept in an orderly manner to prevent the load from collapsing. It needs to be placed.

However, conventionally, even if the robot hand is accurately positioned at the transfer location, the position of the transferred article may shift slightly. The cause of the displacement of the article is considered to be as follows. In other words, when gripping an article with the grip claws coming closer to each fluid cylinder, there is a slight difference in the acting force between the two fluid cylinders or a difference in the degree of friction at the friction points when the two grip claws move. As a result, there is a difference in the spades in which the two grip claws approach each other, and the grip claw that comes into contact with the article sooner pushes the article in the direction of movement of the grip claws, causing the two grip claws to hold the article. When the article was clamped, the article was clamped near the grip claw that had the slower speed. The difference in speed varies from time to time, and therefore, the position where the grip claws hold the object is not a constant position with respect to the main body of the robot hand.

This invention creates a robot hand that does not have the above-mentioned problems, and also does not have the drawbacks that the grip claws do not open easily even if stress is applied to the gripped object in the direction of opening the grip claws, causing the object to drop. This is what we are trying to provide.

[Means for solving problems]

The robot hand of this invention, which solves the above problem, has first and second fluid cylinders installed at opposing positions with their respective piston rods protruding outward, and each piston rod is fixed to the tip of the fluid cylinder. a grip claw, a first conduit that connects fluid chambers on the rod side of the first and second fluid cylinders and connects to a fluid source via a switching valve, and the first and second fluid cylinders. a second pipe line that connects the fluid chamber on the head side of the cylinder and connects to the fluid outlet via a switching valve; and a first pipe line on the rod side of the first fluid cylinder.
a set pressure transformer that is interposed in the pipe line to increase the fluid pressure of the fluid flowing into the fluid chamber on the rod side of the first fluid cylinder; When moving the piston rods together in the retraction direction to clamp an article, always
The grip claws of the fluid cylinder are configured to exert a larger clamping force on the article than the grip claws of the second fluid cylinder, and the first and second fluid cylinders are configured to clamp the article. In some cases, the first
The strokes are set such that the amount of movement of the piston rod of the second fluid cylinder to the retraction side stroke end is larger than the amount of movement of the piston rod of the second fluid cylinder to the retraction side stroke end.

[Effect]

Since the robot hand of this invention is constructed as described above, after the pair of grip claws come into contact with the object, the grip claw with the stronger pressing force moves the object toward the other grip claw with the weaker pressing force. As the object is pushed in, when the piston rod of the fluid cylinder with the weaker pushing force is fully extended, the pushing stops and the object is held between the two grip claws. Since the point at which the piston rod of the fluid cylinder is fully extended is always the same, the article is always held at a constant position relative to the main body of the robot hand.

Further, the fluid cylinders are disposed at opposing positions with their piston rods protruding outward, and the article is clamped at the point where the piston rod of the fluid cylinder with the weaker force is fully extended, so that the article can be gripped. Even if a force is applied in the direction of opening the claws, the grip claws do not open easily and the article does not fall.

〔Example〕

FIG. 1a is a partially longitudinal side view showing the robot hand of this embodiment. This robot hand 1 is 1
A pair of grip pawls 2, 3, grip pawl opening/closing devices 4, 5 for moving the grip pawls 2, 3, respectively, and the grip pawls 2, 3 and opening/closing devices 4, 5 integrally pivoted relative to the support shaft 6. It consists of a turning section 7 that rotates.

First, starting with the swing section 7, a drive shaft 10 of a swing motor 9 is fixed to a support shaft 6 that supports the entire robot hand 1 via a plate 8. Reference numeral 11 indicates a horizontal plate to which the motor 9 is fixed, and a rotary cylinder 13 is fixed to the plate 11 via a connecting member 12.

The drive shaft 10 is inserted into the rotary cylinder 13 via bearings 14 and 15, and the shaft 10 is rotatable relative to the rotary cylinder 13, or the rotary cylinder 13 is rotatable relative to the shaft 10. There is. Vertical plates 16 and 17 are fixed to both ends of the horizontal plate 11, respectively, and a frame 18 is fixed to the vertical plates 16 and 17. Note that 19 indicates a turning angle detection device. In this embodiment, the plate 8 and the drive shaft 10 connected to the support shaft 6 are fixed so as not to rotate, so when the swing motor 9 is operated, the swing motor 9 and the horizontal plate 11 are rotated around the drive shaft 10. And the rotating cylinder 13 rotates.
As mentioned above, the vertical plates 16, 17 and the frame 18 are connected to the plate 11,
Further, since the vertical plates 16, 17 and the frame 18 support opening/closing devices 4, 5 and grip claws 2, 3, which will be explained later, the rotation motor 9
The opening/closing devices 4, 5 and the grip claws 2, 3 rotate together as a result of the operation.

Next, to explain the grip claw opening/closing devices 4 and 5, a left fluid cylinder (second fluid cylinder) 20 and a right fluid cylinder (first fluid cylinder) 21 are fixed to the vertical plates 16 and 17, respectively. The tips of piston rods 22 and 23 of both fluid cylinders 20 and 21 are fixed to grip claws 2 and 3, respectively. In addition, in FIG. 1, the left opening/closing device 4 and the right opening/closing device 5 have the same structure except for the air circuit for supplying air to the cylinders 20 and 21, so the same parts have the same names. and an explanation at the same time. The frame 18 includes supporting members 24, 25 and supporting members 26, 2.
7 is fixed, and guide rods 28 and 29 are respectively installed on the support members. Sliders 30 and 31 are fitted into the guide rods 28 and 29 so as to be slidable along the guide rods. As shown in FIG. 1b, two guide rods 28, 28 are inserted into each slider 30 to prevent the slider 30 from turning.

The sliders 30 and 31 have grip claws 2 and 3.
are fixed respectively, and both grip claws 2,
Cushion materials 32 and 33 are fixed to opposing surfaces of the members 3. Reference numerals 34 and 35 indicate limit switches, which detect that the article B has come into contact with the cushion materials 32 and 33.

The air pressure of the air supplied to the right fluid cylinder 21 is set higher than the air pressure of the air supplied to the left fluid cylinder 20. That is, Fig. 2 shows a schematic diagram of the air piping, and the air sent from the air pressure source A passes through the pressure reducing valve PV, and then branches into the pipes T1 and T2, and passes through the switching valves V1 and V2, respectively, to the left and right pipes. fluid cylinder 2
0,21. On the right fluid cylinder 21 side, a set pressure changer CR is provided after the switching valve V1, and the changer CR increases air pressure and supplies air to the right fluid cylinder 21. Note that E indicates the air outlet.

The operation when the robot hand 1 having the above structure holds the article B will be described next. In addition,
In this embodiment, the article B is, for example, a bundle of many printed books, and is quite elongated.

From the state shown in FIG. 1, both fluid cylinders 20,
Air is supplied to 21 to move the two grip claws 2 and 3 toward each other. When the cushioning materials 32 and 33 of the grip claws come into contact with both sides of the article B, respectively, as shown in FIG.
receive. Since the air pressure sent to the right fluid cylinder 21 is higher than that of the left fluid cylinder 20, the pressing force F2 by the right grip pawl 3 is stronger than the pressing force F1 by the left grip pawl 2. Therefore, article B is pushed and moved in the direction of arrow 35 while being held between both claws 2 and 3. As shown in FIG. 3b, the piston rod 2 of the left fluid cylinder 20
2 is fully extended, the movement of the article in the direction of the arrow 35 stops. In the stopped state, the entire hand 1 is moved to transfer the article. Note that the difference between the pressing force F2 and the pressing force F1 is set to be at least enough to allow the article to move in the direction of arrow 35.

When releasing the article B held between the claws 2 and 3, the switching valves V1 and V2 are switched, and the piston rod 22,
23 from the respective fluid cylinders 20, 21, and the above-mentioned clamping forces F1, F2 are released. The position at which the article B is released is always positioned at the point where the piston rod 22 of the left fluid cylinder 20 is fully extended, so it is always at the same position with respect to the body of the hand 1. The piston rod 22 of the left fluid cylinder 20 is already fully extended when releasing the article B, so it will not extend any further even if the switching valve V2 is switched, but it is switched to release the clamping force F1.

Note that the left and right fluid cylinders 20 and 21 are as follows:
When the rods are both contracted to clamp the article B, the amount of movement of the piston rod 23 of the right fluid cylinder 21 to the retraction side stroke end is greater than the amount of movement of the piston rod 22 of the left fluid cylinder 20 to the retraction side stroke end. Each stroke is set to be larger than the amount of movement.

[Effect of idea]

As explained above, according to the present invention, the object is always held by the grip claws at a fixed position relative to the main body of the robot hand, and if the entire hand is positioned accurately, The article to be released is provided with precise positioning.
Therefore, it was possible to keep the group of articles transferred by the hand in an orderly state, and it was possible to prevent the group of articles from collapsing.

In addition, since a set pressure changer is provided in the middle of the pipe connected to the fluid chamber on the rod side of one fluid cylinder, the fluid pressure flowing into one fluid cylinder is changed by the set pressure transformer. By doing so, the difference in the acting force between the two fluid cylinders can be set to any desired value, and due to wear of the sliding parts when the grip claws move, differences in manufacturing accuracy, etc. This eliminates the drawbacks that the cylinder does not move with the desired force, the difference in force between the two fluid cylinders is not sufficient, and the positioning location is not constant.

Furthermore, the fluid cylinders are provided at opposing positions with the piston rods protruding outward, such that the piston rod of the fluid cylinder with the weaker force is fully extended, and the fluid cylinder with the stronger force is still at the end of its stroke. Since the article is held in a state where the article is not reached, even if a force in the direction of opening the grip claws is applied to the article, the grip claws will not open easily and the article will not fall.

In other words, even if a force acts in the direction of further elongating the fluid cylinder with the weaker force (in the direction of arrow 35), the fluid cylinder with the weaker force is in the fully extended state at the article clamping position shown in FIG. Therefore, even if the grip claws do not open and a force is applied in the direction of further extending the fluid cylinder with the stronger force (in the opposite direction of arrow 35), the acting force is equivalent to making a hole in the fluid cylinder with the stronger force. Even if the grip pawls are opened, the grip pawls on the other side are constantly urged in the direction of pressing the article by the fluid cylinder with the weaker force, so both grip pawls can be opened. Accidents such as opening both doors and dropping items will not occur.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of a robot hand to which the present invention is applied, Fig. 1a is a partially vertical side view, Fig. 1b is a sectional view taken along line X--X in Fig. Schematic diagram of the air piping of the embodiment shown in Figure 1, Part 3
Figures a and b are schematic side views for explaining the operation of the embodiment of the present invention. 2, 3... Grip claw, 20... Second fluid cylinder, 21... First fluid cylinder, 22, 2
3... Piston rod, F1, F2... Article pressing force, A... Fluid source, B... Article, T1, T2...
Piping, V1, V2...Switching valve, CR...Set pressure changer, E...Fluid outlet.

Claims (1)

[Scope of utility model registration request] the fluid cylinders are provided with first and second fluid cylinders arranged at opposing positions with their piston rods protruding outward, gripping claws fixed to the ends of the piston rods of the fluid cylinders, a first pipeline connecting the insides of the fluid chambers on the rod sides of the first and second fluid cylinders and connecting them to a fluid source via a switching valve, a second pipeline connecting the insides of the fluid chambers on the head sides of the first and second fluid cylinders and connecting them to a fluid outlet via a switching valve, and a set pressure changer interposed in the first pipeline on the rod side of the first fluid cylinder for increasing the fluid pressure of the fluid flowing into the fluid chamber on the rod side of the first fluid cylinder,
When the piston rods of the fluid cylinders are moved in the retracting direction together to clamp the article, the first
The gripping claw side of the first fluid cylinder applies a larger clamping force to the article than the gripping claw side of the second fluid cylinder, and when the first and second fluid cylinders clamp an article,
A robot hand characterized in that the strokes of the first fluid cylinder and the second fluid cylinder are set so that the amount of movement of the piston rod of the first fluid cylinder to its retracting stroke end is greater than the amount of movement of the piston rod of the second fluid cylinder to its advancing stroke end.