GB2250264A

GB2250264A - Suction pad.

Info

Publication number: GB2250264A
Application number: GB9123333A
Authority: GB
Inventors: Shigekazu Nagai; Shuuzou Sakurai; Tadasu Kawamoto
Original assignee: SMC Corp
Current assignee: SMC Corp
Priority date: 1990-11-08
Filing date: 1991-11-04
Publication date: 1992-06-03
Anticipated expiration: 2011-11-04
Also published as: DE4136359C2; JPH0473612U; DE4136359A1; JP2586261Y2; GB2250264B; GB9123333D0

Description

2230264 Suction Pad The present invention relates to a suction pad

designed to hold a work in a suction manner to transport it to any location.

A suction pad connected to a vacuum source has been conventionally used, for example, in order to transport a thin plate-like work. A suction pad of this type usually comprises a root part 4 and a skirt part 6 integrally connected to the root part 4, as shown in Figs. la and lb, and is mounted to an arm of a robot through a connectgr (not shown) and used to transport a work. More specifically, a tube from the vacuum source is connected to the root-part 4 of the suction pad 2, so that a work can be held and transported in a suction manner by the suction pad 2 with the skirt part 6 depressurized by an evac uation from thevacuum source through the tube.

Such a suction pad is formed of a natural or synthetic rubber or the like, so that it can be brought into close contact with a work, and an airtightness can be maintained.

However. the prior art suction pad suf f ers f rom a problem that af ter a work has been held and transported in the suction manner by the suction pad and released from the suction pad, a suction mark may be left on a work.

The suction mark provided by the suction pad may be 1 f ormed by a breaking of the bond between molecules of the natural or synthetic rubber to cause a constituent to be exposed and deposited on a surface of the work, when the skirt part 6 has been bent upon holding of the work in the suction manner. In addition, the suction pad may contain additives required to produce the suction pad in a molding manner, such as a vulcanizer, a vulcanizing accelerator, an age resistor, a filler, a plasticizer, a processing aid, a mold release agent and/or the like and therefore, it is believed that such suction mark may be also partially caused by an influence of these chemicals.

The suction mark on the surf ace of the work may exert the following adverse affections in some cases:

when a work is a mirror, a glass, a lens, a cathode ray tube or the like, the aesthetic appearance of the work may be injured by a suction mark left on the workr and the value of a commercial article may be reduced. Additionally, when a liquid crystal, a semiconductor or the like is held and transported in a suction manner, an adverse affection may be exerted to a working environment and atmosphere by leaving of a suction mark thereon.

-2 Therefore, the prior art has required an operation for eliminating such a suction mark by use of chemicals.

Further. in the shape of the prior art suction pad, the skirt is largely bent under a depressurization and sucked to a work and hence., a suction mark is liable to be left on the work and may be increased in size.

Accordingly, it is an aim of the present invention to provide a suction pad designed so that no suction pad mark is left on a work.

The present invention provides- a suction pad comprising a root part to be connected to a vacuum source, and a skirt part integrally connected to the root part, wherein a material used to form the suction pad is a synthetic polymer having a strong intermolucular bond.

Preferably, the material is at least one resin selected from the group consisting of a flexible fluoroplastic, a flexible vinyl chloride resin, a flexible polyurethane resin, a flexible polyethylene resin and a flexible polypropylene resin.

Preferably, the hem of the skirt part is formed with a larger thickness, and the skirt part is formed to provide a small contact surf ace when the work is held in a suction manner by the suction pad.

Preferably, the shape of the skirt is such that the skirt part is bent to a small extent when the work is held in a suction manner by the suction pad.

In the suction pad according to the present invention, it is possible to mold the suction pad by which no suction mark is deposed on a work, by using a material of the type described, the bond of molecules of which cannot be broken, thereby preventing a constituent from being exposed.

1 In addition, even if such a material is used, it is possible to insure a suction force and an air-tightness similar to those in the prior art suction pad formed of a rubber.

Further, the contact surface is reduced in size by the f ormation into a shape of the skirt part such that the skirt part is bent to the small extent, when the work is held in the suction manner by the suction pad, resulting in providing. This also provides an effect that a suction mark is hard to be deposited on the work.

1 1 i The above and other objects, features and advantages of. the invention will become apparent f rom a consideration of the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.

Fig. la is a perspective view of a prior- art suction pad; Fig. lb is a longitudinal sectional view taken along a line W-W in Fig. la; FIG according to Fig along a line Fig according to Fig along a line Fig according to and Fig. 4b is a longitudinal sectional view taken along a line III-III in Fig. 4a.

1 2a is a perspective view of a suction pad a first.embodiment of the present invention; 2b is a longitudinal sectional view taken I-I in Fig. 2a; 3a is a perspective view of a suction pad a second embodiment of the present invention; 3b is a longitudinal sectional view taken II-II in Fig-. 3a; 4a is a perspective view of a suction pad a third embodiment of the present invention; -5 A f irst embodiment of the present invention will now be described.

Referring to Figs. 2a and 2b. a suction pad 10 according to a first embodiment of the present invention comprises a mounting part 14 to be connected to a vacuum source (not shown) through an opening 12 provided in an upper portion thereof, a roqt part.16 connected to a lower portion of the mounting part 14, and a skirt part 18 integrally connected to the root part 16.

More specifically, the circular opening.12 is provided at a substantially central portion of the mounting part 14, so that a connector (not shown) used as a f itting can be inserted through: the opening 12 and connected to a tip or leading end of an arm in a robot (not shown)-.' The root part -16- has a substantially circular section and has an outer. periphery which is gradually increased in diameter and connected to the skirt part 18.

The skirt part 18 also has a substantially ci rcular section larger than that of the root part 16. A hem 20 extends from a base end to a leading or terminal end of the skirt 18 and is integrally formed so that the thickness thereof may be gradually reduced from the base end to the leading or the terminal end of the skirt 18. A through-hole is provided in the. skirt 18 at a substantially central portion of an interior bottom surface thereof adapted to 1 1.

come into contact with a work and extends from the skirt bottom surface 21 to the opening 12. The through-hole provides an air evacuation bore 22 for evacuating air by connection to the vacuum. source (not shown) through a connector (not shown).

The suction pad constructed in the above manner will be described below.

The suction pad 10 is f ormed so that the terminal end of the skirt 18 has a thickness larger than that of the prior art skirt 6 and the skirt 18 has a height smaller than that of the prior art skirt 6. Thus, when then the work has been held in a suction manner by the suction pad, the bend of the hem 20 of the skirt 18 is smaller than that in the prior art and hence, a suction mark is hard to be left.

Further, with the skirt part 6 in the prior art, the contact surface is increased by bending of the hem 38 when the work has been held in the sucked manner To the contrary, with the suction pad 10 of this embodiment, the contact surface to the work can be reduced in size by providing an increased thickness of the hem 20 of the skirt 18, as described above.

The operation of the suction pad constructed in the above manner will be described below.

The suction pad 10 is mounted on the tip or leading end of an arm ot a robot and is sucked f rom the vacuum source (not shown) through the air evacuation bore 22 extending through the root part 16 and the skirt part 18. -7- As a result of such suction, a work is held in a suction manner by the suction pad 10 under a depressurization of the skirt part 18 and can be transported in this state.

It should be noted that the work can be transported to a predetermined location without a suction mark left on the transported work due to the suction-holding by the suction pad.

The conceivable cause of deposition of the suction mark provided by the suction pad is that when a material such as a synthetic rubber is used, the bond between molecules thereof is brokenr so that a constituent is exposed and deposited on the work. The suction pad 10 according to the present embodiment is formed in a molding manner by using a material such as a resin with a sufficient strong intermolecular bond such that the bond between molecules cannot be easily broken in the above manner, e.g., a flexible thermoplastic resin which is a synthetic polymer compound.

Particular materials which may be used include, for example, a flexible vinyl chloride resin, a flexible polyurethane resinr a flexible polyethylene resin, a flexible polypropylene resin, and fluoroplastic such as flexible polytetrafluoroethylene resin. More preferably, a flexible fluoroplastic resin (e.g., a material commercially available under a Japanese trade name of "-e_-7;7iV,)-7 I, i 1 1.

IT i i J 1 1 which is to be pronounced as "Sefural Soft" from Central Glass Co., Ltd.) is most suitable.- These resins have a strong intermolecular bond and therefore, even through the skirt 18 is bent upon holding of the work in a suction manner, the intermolecular bond is hard to be broken. This ensures that the exposure of a constituent can be inhibited, and a filler, a plasticizer and/or the like can be prevented from being precipitated out of the resinous material.

If any one of these resins is used, it is possible to reduce the amounts of a filler., a plasticizer and/or the like which may be contained in a material used in the prior art such as natural and synthetic rubbers, with the result that a suction mark is hard to be left. Moreover, if the above-described material 4"Sefural Soft") is used, it is possible to dispense with the filler, the plasticizer and the like.

Further, the use of such a flexible resin as a material for the suction pad ensures that the suction surf ace of the suction pad can f ollow a surf ace of a work when the work is held in a suction manner and hence, the suction pad is brought into--close contact with the work, so that an air-tightness is maintained, and the transporting performance cannot be reduced.

Yet further, because these resins are transparent materials, the use of any one of these resins ensures that the held state of the work can be visually observed, and the suction pad can be freely colored.

A second embodiment of the present invention will now be described. Referring to Figs. 3a and 3b, a suction pad 40 of the second embodiment comprises a mounting part 44 having a circular opening 42 at its upper portion, a substantially disk-shaped root part 46 connected to a lower portion of the mounting part 44, and a skirt part 48 projecting downwardly from an outer periphery of the disk-shaped portion and integrally connected with the root part 46, as in the first embodiment. There is an air evacuating bore 52 comprising a through-hole extending from a substantially central portion of a bottom surface 50 of the root part 46 to the opening 42.

The feature of the suctio n pad of the second embodiment is that the skirt 48 is formed with a very small height, and a terminal end 49 of the skirt 48 is formed to project at an acute angle so that the contact surf ace to a work is as small as possible. This ensures that a work can be held in a suction manner and transported by the suction pad without bending of the skirt 48 upon such holding.

i n A third embodiment of the present invention will now be described. Referring to Figs. 4a and 4b, a suction pad of the third embodiment also comprises a columnar mounting part 56 likewise having a circular opening 54 at a central portion thereof, a columnar root part 58 integrally connected to a lower portion of the mounting part 56, and a skirt part 60 provided in the form of a circumferential projection below the root part 58. There is also an air evacuating bore 64 comprising a through-hole extending from a substantially central portion of a bottom surface 62 of the root part 58 to the opening 54.

The suction pad of the third embodiment has a feature in that a surface 66 of the skirt 60 adapted to come into contact with a work is a flat surface parallel to a surface of the work., rather than a pointed shape as shown in Fig. 2b.

The operation of the suction pads according to the second and third embodiments is similar to that of the first embodiment and hence, the detailed description thereof is omitted.

In additionr the suction pads 40 and 52 according to the second and third embodiment may be made of a material same as that in the first embodiment.

Claims

CLAIMS:

1. A suction pad comprising a root part connected or connectable to a vacuum sourcer and a skirt part integrally connected to the root part, wherein a material used to mold the suction pad is synthetic polymer having a strong intermolecular bond.

2. A suction pad according to claim 1, wherein said material is at least one resin selected from the group consisting of a flexible fluoroplastic resin, a flexible polyvinyl chloride resin, a flexible polyurethane resin, a flexible polyethylene resin and a flexible polypropylene resin.

3. A suction pad according to claim 1 or 2, wherein a hem of the skirt part is formed- with a large thickness, and -the skirt is formed to provide a small contact surface when_ a workpiece is held in a suction manner by the suction pad. --

4. A suction pad according to claim 1, 2 or 3, wherein the shape of the skirt part is such that the skirt part is bent to a small extent when a workpiece is held in a suction manner- by the suction pad.

5. A suction pad comprising a root part for connection to a vacuum source and a skirt part integral withthe root part, the suction pad being composed of a non-marking synthetic polymer.

6. A suction pad substantially as hereinbefore described with reference to Figures 2, 3 or 4.

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