JP2007038363A - Gripper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripper capable of gripping an article at a high speed with a strong gripping force while using a low output motor.
SOLUTION: When restoring from the stretched state, a gripping resilient member 5 forcibly swinging in a closing direction of the gripping members 1 and 2, and the product of horsepower and speed is the elasticity of the gripping resilient member 5. In a state in which the driving unit 10 smaller than the product of the restoring force and the restoring speed, the amplifying unit 9 that amplifies the driving force of the driving unit 10 and extends the gripping elastic member 5, and the gripping elastic member 5 is extended. And a locking member 11 that locks to prevent the restoration and can be unlocked by external control, and when the lock is released, the gripping mechanism is strongly gripped by the restoring force of the gripping elastic member 5 Holds an article at high speed with force.
[Selection] Figure 1

Description

  The present invention relates to an improvement of a gripper for gripping an article.

In recent years, robots are used in various fields, and in many applications, a mechanism for a robot to grip an article is required. Therefore, a gripper that grips an article by swinging a clamp jaw by a driving force of a motor or the like is used (for example, Patent Document 1).
The gripper is required to have various shapes and functions depending on the application, but due to the restriction of being incorporated in the robot arm, it is essential to reduce the size and the structure, and the use of a low-power small motor is generally used. Therefore, in order to reinforce the gripping force of the gripper and increase the speed of gripping, the driving force of the motor is amplified by a gear or the like and speeded up.
JP 2000-225590 A

However, the amplification of the driving force using a gear or the like has a problem that it brings about a trade-off between the gripping force and the gripping speed. The field of use of robots is expected to increase in the future, and depending on the application, there may be situations where the gripper is required to have a strong and high-speed gripping performance.
In view of such problems, an object of the present invention is to provide a gripper that can grip an article at high speed with a strong gripping force while using a low-power motor.

  In order to achieve the above object, a gripper according to the present invention includes a pair of clamp jaws, and is connected to the gripping mechanism for gripping and releasing gripping of the article by opening and closing the clamp jaw, and is tensioned. When restoring from the state, the restoring force is transmitted to the clamp jaws, and the product of the elastic force and the elastic force of the resilient member is the product of the resilient member that forcibly swings in the direction of closing the clamp jaw and the horsepower and the speed. When the elastic member is smaller than the product of speed and the elastic member is in a restored state, a low-speed high horsepower drive mechanism that changes the elastic member to a tension state based on an instruction from the outside, and the elastic member is in a tension state When the transition is made, it is locked to prevent its restoration, and a lock mechanism that can be unlocked by an external instruction is provided. When the lock is released, the gripping mechanism is strongly gripped by the elastic restoring force of the elastic member By force It is characterized by performing gripping of the article quickly.

With the above-described configuration, the gripper according to the present invention uses a low-speed, high-horsepower driving mechanism as a mechanism for amplifying the driving force of a low-output motor with a gear or the like, thereby extending a resilient and resilient member that is restored at high speed. The article can be gripped with high speed and high horsepower by the restoring force and restoring speed of the elastic member.
Therefore, an article can be gripped at a high speed with a strong gripping force while using a low output motor.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cutaway view of a gripper 100 according to the present invention. The gripper 100 includes a holding member 1, a holding member 2, an opening elastic member 3, a block member 4, a holding elastic member 5, a connecting string 6, a pulley 7, a connecting string 8, and an amplifying unit 9. , Drive unit 10, locking member 11, locking elastic member 12, connecting string 13, pulley 14, amplification unit 15, and driving unit 16.

  The gripping member 1 is integrally formed of a jaw portion 1a, a cutout portion 1b, and an attachment portion 1c. An insertion hole for the support shaft 20a is formed in the cutout portion 1b, and the gripping member 1 is retained on the side surface of the jaw portion 1a. A pin 1d is protruded. The gripping member 2 is integrally formed of a jaw part 2a, a notch part 2b, and an attachment part 2c, and an insertion hole for the support shaft 20a is formed in the notch part 2b, and is retained on the side surface of the attachment part 2c. A pin 2d is projected. In addition, the gripping members 1 and 2 are supported by the housing 20 so as to be swingable by inserting a support shaft 20a projecting from the housing 20 into an insertion hole between the notch 1b and the notch 2b. Forming mechanism.

The release resilient member 3 is formed of a coil spring, and is stretched between the retaining pin 1d of the gripping member 1 and the retaining pin 2d of the gripping member 2, and the elastic force of the jaws 1a and 2a is separated. Acts like
The block member 4 is supported by a guide rail 20b protruding from the housing 20 so as to be movable in the left-right direction in the figure.

  The holding elastic member 5 is formed of a coil spring, and is stretched between a fixed claw 20c protruding from the housing 20 and the left side surface of the block member 4 facing the fixed claw 20c. Is fixed to the fixed claw 20c and the block member 4. The coil spring of the holding elastic member 5 is a so-called tension spring, and its elastic force acts in a direction to pull the block member 4 back to the left in the drawing.

  The connecting string 6 is a Y-shaped string that connects the gripping members 1 and 2 and the block member 4 of the gripping mechanism, and one end connected to the gripping mechanism branches into branches 6a and 6b. One end that is fixed to the end portions of the mounting portions 1c and 2c and is connected to the block member 4 is fixed to the right side surface of the block member 4 that faces the surface on which the gripping elastic member 5 is fixed. The connecting string 6 is spanned between the gripping mechanism and the block member 4 via a pulley 7, and the block member 4 slides to the left in the drawing to draw the attachment portions 1 c and 2 c together, and the jaw portion 1 a, 2a is brought into contact. Here, since the coil spring of the holding elastic member 5 is stronger than the coil spring of the releasing elastic member 3, no tension is applied to the connecting string 8, and the locking member 11 comes into contact with the block member 4. In a state where the grip member is not in the closed state, the block member 4 is pulled back to the left by the gripping elastic member 5, and the jaws 1a and 2a come into contact with each other and the gripping mechanism is closed.

The pulley 7 is a pulley that is pivotally supported by a support shaft protruding from the housing 20.
One end of the connecting string 8 is fixed to the same side as the surface of the block member 4 to which the connecting string 6 is fixed, and the other end is wound by a winding roller 9a.
The amplifying unit 9 and the driving unit 10 constitute a low-speed high horsepower driving mechanism that stretches the gripping elastic member 5 via the connecting string 8. In the low-speed high-horsepower drive mechanism, the product of the horsepower and the speed for pulling the connecting string 8 is smaller than the product of the elastic restoring force and the restoring speed of the gripping elastic member 5.

The amplifying unit 9 is formed of a winding roller 9a and an amplifying roller 9b, and amplifies the torque obtained by driving the driving unit 10 to wind the connecting string 8.
The drive unit 10 is a DC motor whose direction of rotation is reversed by the direction of an electric current supplied from the outside, and supplies an external force that stretches the gripping elastic member 5 by winding the connecting string 8 with a winding roller 9a.

  The locking member 11 is supported by a guide rail 20d protruding from the housing 20 so as to be movable in the vertical direction in the figure, and the block member 4 is slid to the right from the right side surface of the locking member 11. Thus, the locking member 11 is slid upward in the figure, so that it can contact the left side surface of the block member 4, and the block member 4 can be locked with the gripping elastic member 5 extended.

  The locking resilient member 12 is formed of a coil spring, and is disposed between a fixed claw 20e projecting from the housing 20 and the lower surface of the locking member 11 facing the fixed claw 20e. The portion is fixed to the fixing claw 20e and the locking member 11. The coil spring of the locking elastic member 12 is a so-called compression spring, and its elastic force acts to push the locking member 11 upward in the drawing.

One end of the connecting string 13 is fixed to the same surface as the surface of the locking member 11 to which the locking elastic member 12 is fixed, and the other end is wound up by a roller of the amplifying unit 15 via the pulley 14. Yes.
The pulley 14 is a pulley that is rotatably supported by a support shaft that protrudes from the housing 20.

The amplifying unit 15 and the drive unit 16 constitute a release drive mechanism that moves the locking member 11 from the contact position with the block member 4 to release the locking.
The amplifying unit 15 amplifies the torque obtained by driving the driving unit 16 and winds the connecting string 13.
The drive unit 16 is a DC motor whose direction of rotation is reversed by the direction of an electric current supplied from the outside, and supplies a driving force for compressing the locking elastic member 12 by winding the connecting string 13 by the amplifying unit 15. To do. The above is the description of the configuration of the gripper 100 according to the present embodiment.
<Operation>
Next, an operation of gripping an article in the gripper 100 according to the present embodiment will be described with reference to FIGS. The operation of the gripper 100 is controlled by supplying current to the driving units 10 and 16.

  FIG. 2 is a diagram schematically showing the gripper 100 in a standby state that can be started. In the state of FIG. 2, the locking member 11 is brought into contact with and locked with the block member 4, whereby the gripping elastic member 5 is maintained in the stretched state, and the jaw of the gripping mechanism composed of the gripping members 1 and 2. Are separated by the elastic force of the opening elastic member 3. For this reason, only the tension | tensile_strength is applied to the connection string 6 by the releasing elastic member 3 separating the jaw part of a holding | grip mechanism. On the other hand, the connecting string 8 has a slack 8a between the block member 4 and the winding roller 9a. The amount of this slack is adjusted so that tension is generated in the connecting string 8 when the block member 4 slides to the left until the jaw of the gripping mechanism closes.

  From this state, the gripper 100 starts when the locking member 11 is pulled down in the drawing. FIG. 3 is a diagram schematically showing how the gripper 100 starts from a standby state and grips the article X. In order to pull down the locking member 11, as shown in FIG. 3, an electric current is supplied to the drive unit 16 so that the amplification unit 15 rotates in a direction in which the connection string 13 is wound up. As a result, the locking with the block member 4 is released, the gripping elastic member 5 is rapidly retracted from the stretched state, and the block member 4 is pulled to the left in the drawing. At this time, since the elastic force of the holding elastic member 5 exceeds the elastic force of the releasing elastic member 3, the holding member 1 connected to the elastic member 5 for holding via the block member 4 and the connecting string 6, The two attachment portions are pulled toward each other, and the jaws of the gripping mechanism are closed with high speed and high horsepower to grip the article. Note that the supply of current to the drive unit 16 from the outside stops after the locking by the locking member 11 is released.

  In order to release the gripping mechanism from the state in which the article X is gripped, a current is supplied to the drive unit 10 so that the winding roller 9a rotates in a direction to wind the connecting string 8. FIG. 4 is a diagram schematically showing a state in which the gripper 100 releases the gripping mechanism from the state in which the gripper 100 grips the article X. When the connecting string 8 is wound up by the take-up roller 9a, the block member 4 is pulled by the connecting string 8 and moved to the right in the drawing, whereby the gripping elastic member 5 is stretched and fixed to the block member 4. The tension of the sagging connection string 6 decreases. As a result, the elastic force of the opening elastic member 3 exceeds the tension of the connecting string 6, and the jaws of the gripping members are oscillated by the restoring force of the opening elastic member 3 to separate them. Here, further, after the block member 4 has moved to the right side from the locking position with the locking member 11, an electric current is supplied from the outside to the driving unit 16 so that the amplifying unit 15 rotates in a direction in which the connecting string 13 is fed out. . Thereby, the tension of the connecting string 13 is loosened, and the locking member 11 is pushed upward by the elastic force of the locking elastic member 12 so that the locking member 11 contacts and locks the block member 4. Move to the position you want. The current supply to the drive unit 16 stops after moving to a position where the locking member 11 contacts and locks.

  In order to enter a standby state where the gripper 100 can be started again from the opened state, it is necessary to give the connecting cord 8 slack. FIG. 5 is a diagram schematically illustrating a state in which the gripper 100 transitions to a standby state where it can be started again after being opened. In the state shown in FIG. 5, the current supplied to the drive unit 10 in the state shown in FIG. 4 is reversed, and the current is supplied so that the winding roller 9 a rotates in the direction to draw out the connecting string 8. When the connecting string 8 is unwound from the take-up roller 9a, the block member 4 moves to the left in the figure by the elastic force of the gripping elastic member 5, but the locking member 11 is pushed upward by the operation in FIG. Therefore, the block member 4 is locked by the locking member 11 when it moves to the contact locking position with the locking member 11. Thereafter, when the slack 8a is drawn out such that the block member 4 can slide to the left until the jaw of the gripping mechanism is closed, the supply of current to the drive unit 10 is stopped. As a result, the gripper 100 transitions again to the standby state shown in FIG. The above is the description of the operation of gripping an article in the gripper 100 according to this embodiment.

As described above, according to the present embodiment, power is supplied to the drive unit 10 having a low horsepower but a large horsepower at the preparation stage to stretch the gripping elastic member 5 and to stretch the elastic restoring force of the gripping elastic member 5 And the restoration speed, the article can be gripped at high speed and high horsepower.
In addition, by providing the release elastic member 3 in which the elastic force acts in the direction to open the jaw of the gripping mechanism, the opening and closing of the gripping mechanism is controlled by controlling only the low speed high horsepower driving mechanism and the lock mechanism from the outside. be able to.
<Modification>
Although the present invention has been described based on the above embodiment, it is needless to say that the present invention is not limited to the above embodiment. The following cases are also included in the present invention.

(1) In the above-described embodiment, the opening elastic member 3 and the holding elastic member 5 are constituted by a tension spring, and the locking elastic member 12 is constituted by a compression spring. It may be configured. For example, the opening elastic member 3 and the holding elastic member 5 may be formed of rubber strings.
Or as shown in FIG. 6, it is good also as a structure which closes the jaw of a holding member with the restoring force which an elastic body decompress | restores from a compression state. A gripper 200 shown in FIG. 6 has a configuration in which the block member 4 and the gripping resilient member 5 are replaced with a block member 201 and a gripping resilient member 202 in the gripper 100 of FIG.

One end of the gripping elastic member 202, one end of the connecting string 6, and one end of the connecting string 8 are attached to the block member 201 on the left side facing the fixed claw 20c.
The gripping elastic member 202 is disposed between the fixed claw 20 c and the left side surface of the block member 201, and both ends thereof are fixed to the fixed claw 20 c and the block member 201. Here, the holding elastic member 202 is a so-called compression spring, and in the compressed state, the elastic force acts in a direction to push the block member 201 back to the right in the drawing. When the connecting string 6 is wound up by the drive of the drive unit 10, the block member 201 slides to the left in the figure, and the gripping elastic member 202 is compressed. Further, in the gripper 200, the locking member 11 is brought into contact with the right side surface of the block member 201 and locked, thereby maintaining the gripping elastic member 202 in a compressed state.

In such a modification, the article can be gripped at a high speed and a high horsepower by the restoring force of the gripping resilient member 202, which is a compression spring, extending from the compressed state.
(2) In the above embodiment, when the block member 4 slides to the left at a high speed by the elastic force of the gripping elastic member 5, the low-speed high horsepower drive mechanism including the amplification unit 9 and the drive unit 10 is used for gripping. In order to prevent a load from being applied to the restoration of the elastic member 5, the connecting string 8 is slack during standby. However, other configurations may be used as long as the low-speed high-horsepower driving mechanism does not exert a load on the restoration of the gripping elastic member 5.

For example, the amplification roller 9b is moved from a position where the torque of the drive unit 10 is transmitted to the take-up roller 9a (hereinafter referred to as a transmission position) to a position where the torque of the drive unit 10 is not transmitted to the take-up roller 9a (hereinafter referred to as a non-transmission position). By adopting a movable configuration, a so-called clutch mechanism can be provided in the amplifying unit 9.
In such a configuration, the drive shown in FIG. 5 is performed by winding up the connecting string 8 with the amplification roller 9b in the transmission position, locking the block member 4, and then moving the amplification roller 9b to the non-transmission position. The inversion operation of the unit 10 can be replaced. As a result, the time required for the gripper 100 to be in a standby state where it can be started again from the opened state can be further shortened.

  (3) In the above-described embodiment, the connection string 13 is wound up by driving the drive unit 16 to release the lock by the locking member 11. However, high horsepower is not necessarily required to release the lock. For example, the lower surface of the locking member 11 is formed of an inductive body such as iron, and an electromagnet is provided on the upper surface of the fixed claw 20e, so that the locking member 11 is slid up and down by switching the electromagnet ON / OFF to lock the locking member 11 It is good also as a structure to cancel | release.

  (4) The above embodiment and the above modifications may be combined.

  INDUSTRIAL APPLICABILITY The present invention can be applied as a gripper incorporated in a robot arm, and in particular, when using a small motor with a low output due to structural limitations of the robot arm, a function for gripping an article at a high speed with a strong gripping force is required. Useful in applications.

The figure which notched some grippers 100 concerning the present invention. The figure which shows typically the gripper 100 of the standby state which can be started. The figure which shows a mode that the gripper 100 starts from a standby state, and hold | grips the article | item X. FIG. The figure which shows a mode that the gripper 100 releases | releases from the state which hold | gripped the goods X. The figure which shows a mode that the gripper 100 changes to the stand-by state which can be started again after open | release. The figure which shows the modification of the gripper which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gripping member 1a Jaw part 1b Notch part 1c Attachment part 1d Retention pin 2 Gripping member 2a Jaw part 2b Notch part 2c Attachment part 2d Retention pin 3 Opening elastic member 4 Block member 5 Holding elastic member 6 Connecting string 7 Pulley DESCRIPTION OF SYMBOLS 8 Connection string 9 Amplification part 9a Winding roller 9b Amplification roller 10 Drive part 11 Locking member 12 Locking elastic member 13 Connection string 14 Pulley 15 Amplification part 16 Drive part 20 Housing 20a Support shaft 20b Guide rail 20c Fixing claw 20d Guide rail 20e Fixed claw 100 Gripper 200 Gripper 201 Block member 202 Gripping member

Claims (1)

A gripping mechanism that includes a pair of clamp jaws and grips and releases the article by opening and closing the jaws;
A resilient member that is connected to the gripping mechanism and transmits a restoring force to the clamp jaw when restoring from a tension state, and forcibly swings in a direction to close the clamp jaw;
When the product of the horsepower and the speed is smaller than the product of the elastic restoring force and the restoring speed of the resilient member, and the resilient member is in the restoring state, the resilient member is in a tensioned state based on an instruction from the outside. A low-speed high-horsepower drive mechanism that causes a state transition to
A lock mechanism that locks to prevent its restoration when the elastic member is transitioned to a tension state, and can be unlocked by an external instruction;
A gripper characterized in that when the lock is released, the gripping mechanism grips the article at a high speed with a strong gripping force by the elastic restoring force of the elastic member.

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