CN214560981U - Suspension device for suspending a tool of a manipulator - Google Patents

Abstract

The present invention describes a suspension device for suspending a tool of a manipulator, which can also be defined as a damping device or a height compensator. The suspension device includes a body and a rod or telescoping rod passing through the body and slidable between a fully extended position and a fully retracted position. The spring continuously exerts a pushing force on the rod to bring it to the fully extended position. The body is advantageously closed by a sleeve which can be inserted into the end of the body itself by snapping or by pressing, i.e. interference. By using a sleeve with a circular hole, the through rod is free to rotate about its longitudinal axis relative to the body. On the other hand, if it is preferred to prevent rotation of the stem relative to the body, the anti-rotation function of the stem is achieved by providing a portion of the stem with a non-circular cross-section and coupling a sleeve with a bore having a shape complementary to the cross-section of the stem to the body. Moreover, the sleeve through which the rod passes is made of self-lubricating plastic material; due to this feature, the use of grease or lubricating oil can be avoided.

Description

Suspension device for suspending a tool of a manipulator

Technical Field

The present invention relates to a suspension device for suspending tools/implements such as suction cups, grippers and the like of a manipulator, which suspension device is also referred to as a damping device or a height compensator.

Background

In the field of industrial automation, it is known to move objects using a robot arm equipped with one or more suction cups or grippers.

Suction cups are mounted at the end of the robot arm and are connected to an air suction device so that when the suction cups are attached to the object to be picked up, a vacuum can be created inside them to cause them to effectively adhere to the object, at which time the object can be lifted and moved to a new release position. The object is released by stopping suction and lifting the suction cup from the object.

In other applications, a pneumatic or electric gripper is used instead of a suction cup.

Between the robot arm and each suction cup or gripper, there is generally provided a suspension device, also known as a buffer device or a height compensator, whose function is to allow the relative suction cup to maintain its own position on the workpiece to be picked up.

For example, the workpieces to be picked up may also be arched, such as a roof of a car in an automobile factory, which must be moved. In this case, one mechanical arm is equipped with several suction cups, arranged to interact with the roof of the vehicle; not all of the suction cups are in contact with the workpiece at the same time during the movement to approach the workpiece. This is one of the reasons why a compensation system is required.

In practice, the suspension means comprise a body constrained to the end of the robotized arm (the end of the arm) and a rod slidingly inserted in the body, said rod passing or telescoping, for example, with respect to the body, between a fully extended position and a fully retracted position. A spring acting on the rod to resist movement towards the fully retracted position; the spring continues to exert a force urging the rod toward the fully extended position.

The suction cup is constrained to the distal end of the stem, while the proximal end of the stem is connected to an external air suction line, i.e. a vacuum line. In fact, the suspension means are hollow, i.e. both the body and the stem are hollow, so as to define themselves an air suction channel from the suction cup. In the case of a gripper, the gripper is also constrained to the distal end of the rod, which may not be hollow.

The travel of the rod between the fully extended position and the fully retracted position corresponds to the travel of the robot arm which the suspension allows to compensate.

Typically, the body and the rod of the suspension are made of anodized aluminum, steel or brass.

There are some variants in which the rod is free to rotate with respect to the body of the suspension device, and also variants in which such rotation is locked in a device having a rod with a non-circular section, and the body is milled to create a special shoulder that prevents the rod from rotating.

The suspension devices known in the art suffer from some of the drawbacks that the present invention intends to overcome.

First, the manufacture of both suspension devices with rotatable rods and suspension devices with non-rotatable rods requires a particular diversity of components, i.e. a supply of different components and a different assembly of components. On the other hand, in order to minimize costs, it is desirable to simplify and standardize production, while at the same time being able to obtain a suspension device with a rotatable and a non-rotatable rod starting from a common platform.

Another disadvantage is that currently available suspension devices require regular lubrication to keep the rod sliding with minimal friction and to prevent the sliding from generating metallic dust which can deposit on the products being handled. Rather, it is desirable that lubricants should be avoided, especially if the suspension device is used for handling food or pharmaceutical products.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is to provide a suspension device for suspending a tool of a manipulator which overcomes the limitations of the known solutions, is easy to manufacture, uses both a rotatable rod and a rotation-locking rod, is effective even without lubrication, and is at the same time robust.

Accordingly, in a first aspect, the present invention relates to a suspension device for suspending a tool of a suction cup, gripper or other manipulator, also referred to as a height compensator or a buffer device, said suspension device comprising:

-a body fixable to the manipulator;

-a first sleeve insertable in one end of the body;

-a rod inserted at least partially into said body through the first sleeve and sliding between a fully retracted position and a fully extended position with respect to both said body and said first sleeve;

-elastic resistance means for resisting the movement of said rod,

and the distal end of the rod may be constrained to the tool of the manipulator, wherein this first sleeve is inserted in the corresponding end of the body (4) by snapping it in, or by pressing it in an interfering manner.

In particular, the suspension device comprises a body, preferably in one piece, i.e. made in one piece, and a rod inserted at least partially into the body, for example telescopically or through the body. The rod is guided through a hole in a guide sleeve fixed to an end of the body and is slidable relative to the body between a fully extended position and a fully retracted position.

The object is to be firmly constrained to a manipulator, such as a robotic arm. The stroke of the rod with respect to the body of the suspension corresponds to the maximum displacement of the robot arm that the suspension allows to compensate.

An elastic element, for example a spring, is functionally interposed between the body and the rod of the suspension device, the function of which is to continuously exert a thrust on the rod to bring it to the fully extended position.

If the suspension device has to support a suction cup, the suspension device is hollow in order to allow air to be sucked from the suction cup constrained to the rod. In other words, the rod has an internal channel that places the suction cup constrained at the distal end of the rod in fluid communication with an external air aspiration line constrained to the opposite end of the rod, referred to as the proximal end.

Advantageously, the guide sleeve of the rod can be inserted into the corresponding end of the body of the suspension device by snap insertion or by dry pressing, and the sleeve is interchangeable: the sleeve is made in two variants, one with a circular guide hole to allow the rotation of the rod or stem portion about its longitudinal axis, and the other with a non-circular guide hole, for example a polygonal guide hole, to prevent the rotation of the rod or stem portion with a non-circular section.

This solution makes it possible to simplify the assembly of the suspension device and to optimize the supply of components. In fact, the two variants of the suspension device can be identical, except for the guide sleeve. Thus, in the assembly step, the operator only has to choose between the two sleeves. Thus, a common basis for both suspension variants has been obtained, with obvious advantages in terms of time and cost of assembly, which is modular.

The guide sleeve is preferably made of a self-lubricating plastic material, so that the use of lubricants is avoided: a rod, for example made of metal, slides directly on the inner wall of the guide hole of the sleeve.

Drawings

Further characteristics and advantages of the present invention will become more apparent from reading the following detailed description of a preferred but not exclusive embodiment, given for the purposes of illustration only and not of limitation, with the aid of the accompanying drawings, in which:

fig. 1 is a perspective view of a suspension device according to the prior art, which is equipped with a suction cup;

fig. 2 is a perspective view of a suspension device according to the prior art, equipped with suction cups for gripping a workpiece;

fig. 3 is a perspective view of a suspension device according to the prior art, which is equipped with a gripper;

fig. 4 is an exploded view of a first embodiment of a suspension according to the present invention;

FIG. 5 is a longitudinal (vertical) cross-sectional view of the suspension shown in FIG. 4;

fig. 6 is an exploded view of a second embodiment of a suspension according to the present invention;

fig. 7 is an exploded view of a third embodiment of a suspension according to the present invention;

fig. 8 is a perspective view of the suspension shown in fig. 7, assembled.

Detailed Description

Fig. 1 shows a suspension device 1 according to the prior art, equipped with a respective suction cup 2 and connected to an air suction line 3.

The suspension device 1, which may also be defined as a damping device or a height compensator, comprises a body 4 and a rod 5, the body 4 being intended to be constrained to a robotic arm, for example by means of a bracket and a clamp, the rod 5 being inserted into the body 4 and being able to translate with respect to the body 4. The rod 5 is a through rod, i.e. it passes through the entire length of the body 4, so that both ends of the rod 5 remain exposed at all times. The lower end of the rod 5, called the distal end, is the end carrying the suction cup 2, and the upper end, called the proximal end, is the end connected to the air suction line 3. The terms "distal" and "proximal" are selected with reference to the position of the suspension 1 relative to the robotic arm when in use.

Alternatively, the rod 5 may not pass through the body 4, for example, it may be telescopically received in the body 4.

In the suspension device 1, the rod 5 is locked against rotation relative to the body 4.

Fig. 2 shows a suspension device 1 'according to the prior art, which suspension device 1' is equipped with a suction cup 2 for gripping a workpiece P. Unlike the suspension device 1 shown in fig. 1, in this variant the rod 5 is rotatable with respect to the body 4, allowing the workpiece P to rotate.

Fig. 3 shows another suspension device 1 "according to the prior art, which is not equipped with a suction cup 2, but with a gripper C; in this case, the body of the suspension 1 "is not connected to a compressed air line.

In order to assemble the bar 5 and the body 4 of the suspension, the prior art provides a complex system, that is to say the manufacturer must differentiate between the production to meet the need for a suspension in which the bar 5 is rotatable with respect to the body 4 and a suspension in which the bar 5 is not rotatable with respect to the body 4, and this involves making a different body 4 and corresponding bar 5 for each type of suspension. Furthermore, in the suspension device according to the related art, the rod 5 must be continuously lubricated to limit sliding friction and the formation of metal dust in the main body 4.

Fig. 4 shows, in an exploded view, a suspension device 10 according to the invention, equipped with a body 4 and a corresponding rod 5, the rod 5 being at least partially inserted in a sliding manner in the body 4. The rod 5 consists of two parts, i.e. a lower part 5 'and an upper part 5 ", which can be fastened to each other, for example by screwing, or is made in one piece from two parts with different cross-sections, i.e. a lower part 5' and an upper part 5". The lower part 5' comprises a distal end 6 onto which the suction cup 2 or other tool is screwed, and the upper part 5 "comprises a proximal end 7 onto which the suction line 3 is screwed, if necessary.

The upper part 5 "of the rod 5 has a circular section and the lower part 5' has a non-circular section to prevent rotation of the rod with respect to the body 4, as will be explained later. Since the rod 5 is made of a lower part 5' and an upper part 5 "having different cross-sectional shapes, it is not necessary to replace the rod to reconfigure the suspension device to allow or prevent, respectively, rotation of the rod 5 relative to the body 4, as will be explained later.

The suspension 1 further comprises a spring 8 housed in the body 4, the spring 8 having the function of resisting the longitudinal movement of the rod 5.

Fig. 5 is a longitudinal (vertical) cross-sectional view of the fully assembled suspension 10.

The rod 5 is hollow inside. The cavity 9 defines an internal passage for the suction air, which is thus sucked by the suction cups 2 and then passes through the whole of the rod 5 and flows out through the line 3, such as the line available on a robot arm on which the body 4 is fixed.

In fig. 5, the rod 5 is in its fully extended position, i.e. the distal end 6 is at a maximum distance from the body 4. Since the rod 5 is a through rod, in the fully extended position the proximal end 7 abuts the body 4 and the spring 8 also extends. Conversely, in the fully retracted position (not shown), the proximal end 7 is distal to the upper edge of the body 4, the spring 8 is compressed, and the distal end 6 abuts the lower edge of the body 4.

The spring 8 is preloaded so as to continuously exert a thrust on the rod 5, bringing it to the fully extended position.

Reference character H denotes a stroke that the rod 5 can travel. This is a compensation stroke which allows a displacement of the robot arm towards the gripping position of the object to be moved with a corresponding margin. The only thing that compresses the spring 8 is the mechanical arm: when the suction cup 2 reaches the object to be picked up and rests on it, further possible forward movement of the robot arm towards the object is assisted by the suspension device 1.

Advantageously, in the suspension device 10 according to the invention, the assembly is completed by using at least one first sleeve 11 made of plastic material, which first sleeve 11 can be inserted by snapping or pressing it into the lower end of the body 4, i.e. by interference, to guide the rod 5 when the rod 5 is moved precisely with respect to the body 4; the inner surface of the first sleeve 11, which defines a through hole for guiding the rod 5, has a cross section complementary to the cross section of the lower portion 5' of the rod 5.

As can be seen in fig. 4, the lower portion 5' of the rod 5 has a flat shoulder 13, resulting in a rod cross-section that is not perfectly circular. Inside the first sleeve 11, there are two corresponding shoulders 14 to guide the shoulders 13 of the rod 5.

Indeed, thanks to this arrangement, the manufacturer will no longer be forced to differentiate between production to provide two types of suspension 10, in which the rod 5 can rotate with respect to the body 4 or the rod 5 cannot rotate with respect to the body 4, but will simply use the same body 4 and the same rod 5, each time replacing the first sleeve 11. Since the rod 5 has a circular upper portion 5 "and a lower portion 5' with a flat shoulder 13, the rotation of the rod 5 will be achieved by simply mounting the first sleeve 11 with the circular hole, and the anti-rotation function, i.e. preventing the rod from rotating with respect to the body 4, will be achieved by mounting the first sleeve 11 with the internal shoulder 14 as shown in fig. 4.

By enabling the first sleeve 11 to be inserted manually into the body 14 by snapping or pressing, the assembly operation is greatly simplified, since the operator does not need tools. In the example shown in fig. 4, the operator must simply insert the spring 8 into the body 4, pass the rod 5 through the first sleeve 11, the body 4 and the second sleeve 12, then screw the nipple 7 on the upper end of the rod 5, and finally press the first sleeve 11 and the second sleeve 12 into the body 4 of the suspension device 10 without using special tools.

For example, as shown, the first sleeve 11 and the second sleeve 12 are each provided with external knurling, or with deformable fins.

Preferably, the second sleeve 12, which closes the top of the body 4, is also made of plastic material and can be inserted by snapping or pressing this second sleeve 12 into the upper end of the body 4, i.e. by interference. The second sleeve 12 also guides the rod 5 and, together with the first sleeve 11, keeps it coaxial with the body 4.

Preferably, the first sleeve 11, more preferably both the first sleeve 11 and the second sleeve 12, are made of a material having self-lubricating properties, such as polyethylene terephthalate (polytetrafluoroethylene, PTFE) or Polyoxymethylene (POM). This feature avoids the use of lubricants to lubricate the rod 5, which is an important aspect for applications in the food industry, electronics industry, etc., that do not allow for impurities or dirt.

Providing a first sleeve 11, and preferably also a second sleeve 12, which first sleeve 11 and second sleeve 12 can be inserted by snapping or pressing them into the body 4, brings the further advantage that the first sleeve 11 and second sleeve 12 can be easily interchanged by the manufacturer during assembly, for example to meet the customer's post-mortem considerations, and that the suspension arrangement 10 can be easily reconfigured by the end user by simply changing only the first sleeve 11 from a configuration in which the rod 5 is rotationally locked to a configuration in which the rod 5 is rotatable about the longitudinal axis.

Fig. 6 shows a suspension device 10' according to a second embodiment of the invention, which differs from the suspension device 10 shown in fig. 4 and 5 in that the outer side of the body 4 is threaded to allow it to be fastened to an outer body by means of a nut 15, and in that the rod 5 is rotatable relative to the body 4 about a longitudinal axis: the first sleeve 11 defines a circular guide hole for the non-circular portion 5' of the rod 5.

Fig. 7 and 8 show a suspension device 10 "with a further embodiment of the anti-rotation function of the rod 5, which differs from the previously described solution in that it is not intended to support the suction cup 2 directly, but rather to support a suction cup holder block or clamp holder block 16 on the rod 5. The distal end 6' of the rod 5 is a bracket for anchoring to a suction cup holder block or clamp holder block 16, such that the suction cup holder block or clamp holder block 16 may be rotationally secured to the rod 5 by a screw 17. The suspension device 10 "also provides an anti-rotation locking of the rod 5: the shoulder 14 of the first sleeve 11 and the corresponding flat shoulder 13 of the rod 5 are shown. Instead of the nipple 7, a screw 7' with a closed head is provided, which closes the top of the body 4 and the second sleeve 12.

The described suspension devices 10,10',10 "according to the different embodiments have in common that at least the first sleeve 11 and preferably also the second sleeve 12 can be inserted by snapping or pressing them into the body 4 and thus by interference, but simply by hand without the need for tools. Due to this, the first and second sleeves 11, 12 and the stem 5 are easily interchangeable not only by the manufacturer during the assembly step, but also subsequently by the user. This arrangement not only simplifies and speeds up the assembly, thus reducing costs, but also makes the structure of the suspension 10,10',10 "modular, since the manufacturer can use a common platform, i.e. the same body 4, rod 5, spring 8, second sleeve 12, etc., and change only the first sleeve 11 to obtain a suspension 10,10',10" with a rotatable rod 5 or anti-rotation locking lever 5.

Claims (11)

1. A suspension arrangement (10,10',10") for suspending a tool (2, C) of a manipulator, which suspension arrangement can also be defined as a damping arrangement or a height compensator, said suspension arrangement comprising:

-a body (4) fixable to the manipulator;

-a first sleeve (11) insertable in one end of the body (4);

-a rod (5) inserted at least partially in said body (4) through the first sleeve (11) and sliding between a fully retracted position and a fully extended position with respect to both said body (4) and said first sleeve (11);

-elastic resistance means (8) for resisting the movement of said rod (5),

wherein the distal end (6) of the rod (5) is constrainable to a tool (2, C) of the manipulator,

characterized in that the first sleeve (11) is inserted in the respective end of the body (4) by snapping it in, or by pressing it in an interference manner.

2. Suspension arrangement (10,10',10") according to claim 1, characterized in that the first sleeve (11) is exchangeable on the body (4).

3. Suspension device (10,10',10") according to claim 1 or 2, characterized in that said first sleeve (11) is made of a self-lubricating plastic material.

4. Suspension device (10,10',10") according to claim 1 or 2, characterized in that said first sleeve (11) defines a guide hole for said rod (5) and in that:

i) the guide hole is circular and the rod has a cross-section complementary in shape to the guide hole of the first sleeve (11), or the rod has a cross-section which is non-circular but inscribed in the circumference of the guide hole of the first sleeve (11) and in which the rod can rotate, or

ii) the guide hole is non-circular and at least one portion (5') of the stem (5) has a cross-section with a shape complementary to the guide hole of the first sleeve (11), so that the stem (5) can be locked anti-rotation with respect to both the first sleeve (11) and the body (4).

5. The suspension device (10,10',10") according to claim 4, characterized in that the portion (5') of the rod (5) slidingly inserted through the first sleeve (11) has:

a) circular in cross-section and free to rotate about the longitudinal axis of said rod (5) with respect to the first sleeve (11) and with respect to the body (4), or

b) Non-circular in cross-section and guided by the first sleeve (11) without the possibility of rotating about said longitudinal axis with respect to the first sleeve and with respect to the body (4).

6. Suspension device (10,10',10") according to claim 5, characterized in that said portion (5') of said rod (5) inserted through the first sleeve (11) has at least one flat shoulder (13) and in that the first sleeve (11) comprises a corresponding inner flat shoulder (14).

7. Suspension arrangement (10,10',10") according to claim 1 or 2, characterized in that the first sleeve is made of polyethylene terephthalate or polyoxymethylene.

8. Suspension device (10,10',10") according to claim 1 or 2, characterized in that it further comprises a second sleeve (12), said second sleeve (12) being insertable in the end of said body (4) opposite to the end in which said first sleeve (11) is inserted, by snap-insertion or by pressing it in an interference manner.

9. Suspension device (10,10',10") according to claim 8, characterized in that said rod (5) passes through said body (4) and is guided by both said first sleeve (11) and said second sleeve (12) so as to be coaxial with respect to said body (4).

10. Suspension device (10,10',10") according to claim 1 or 2, characterized in that said elastic resistance means (8) consist of a spring housed in said body (4) and functionally interposed between said stem and said body (4) itself.

11. Suspension arrangement (10,10',10") according to claim 1 or 2, characterized in that the stroke (H) of the rod (5) between the fully extended position and the fully retracted position corresponds to the maximum compensatable displacement of the manipulator on which the body (4) is constrained.

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