A gripper for automatic cloth handling equipment

Abstract

 A gripper for the automatic sewing of garments. The gripper comprises a body (1) with at least one operative face (3) and having an inner hollow space, at least one opening in said operative face leading to said hollow space, at least one stud (8) on each of the operative faces projecting slightly above said opening(s), and ducting means (2) for connecting said hollow space to air pumping means adapted to establish at will a reduced pressure within said hollow space.

Description

[0001] The present invention concerns automatic sewing of garments and more specifically gripper means to be mounted on automatic equipment, e.g. so-called robots, and serving for the transfer of material during an automatic sewing cycle and from one station to another.

[0002] During automatic sewing of garments the cloth is processed progressively at different stations and consequently automatic handling is desired for moving the cloth while being processed and also from one station to another. Such automatic handling comprises grasping a piece of cloth, moving the cloth to a work place, putting the cloth in proper position on a sewing machine table, manipulating the cloth during sewing, and again moving the cloth after it is processed from one station of a sewing cycle to another. For the purpose of these automatic handling operations adequate grippers are required and it is the object of the present invention to provide such grippers.

[0003] In accordance with the present invention there is provided a gripper for moving material in automatic sewing of garments, which gripper comprises a body with at least one opexative face and having an inner hollow space, at least one opening in said operational face leading to said hollow space, at least one stud on each operational face projecting slightly above said opening(s), and ducting means for connecting said hollow space to air pumping means adapted to establish at will a reduced pressure within said hollow space.

[0004] - For pick-up a reduced pressure is established within said hollow space and in conseqnence when the gripper is brought close to or in contact with a piece of cloth on a table, the cloth is sucked onto the operative face. The studs on the operative face keep the opening(s) slightly clear of the cloth and table when making the pick-up. This allows the gripper to rest on the cloth for the pick-up without the operative face resting on the cloth which lies on the table. When pressure inside the gripper is reduced the cloth is attracted to the gripper and the gripper does not stick to the table. Upon transportation and arrival at the desired station the reduced pressure inside the gripper is relieved whereby the piece of material is released onto the desired new location.

[0005] In accordance with one embodiment of the invention said body is in the form of a hollow box. In accordance with another embodiment a distributor duct is provided within the body and one or more bores lead therefrom to the operative face.

[0006] The invention is illustrated, by way of example only, in the accompanying drawings in which:

Fig. 1 is an isometric view of one embodiment of the gripper according to the invention with the operative face turned up;

Fig. 2 is an isometric view of the gripper according to Fig. 1 in operation with one form of suspension;

Fig. 3 is an isometric view of a gripper according to Fig. 1 in operation with another form of suspension;

Figs. 4 to 9 show various stages in the handling of a piece of cloth with a robot fitted with a gripper according to the invention; and

Fig. 10 is a plan view of a robot arm terminal fitted with a plurality of grippers according to the invention.

[0007] The gripper according to the invention shown in Fig. 1 comprises a rectangular prismatic hollow body 1 fitted with a tube 2 by which it can be connected to a vacuum pump. Body 1 comprises an operative face 3 having three holes 4 each fitted with a protruding tubular rubber collar 5. Near one of the edges the surface 3 comprises three smaller holes 6 each fitted with a tubular rubber collar 7. Finally, there are provided on face 3 two identical studs 8 which protrude slightly above collars 5 and 7. Collars 5 and 7 are not always required and in some instances they may be disposed with.

[0008] During operation the operative face faces downward and the opposite face 9 is connected to a robot arm, e.g. by means of a stud 10 as shown in Fig. 2 or by means of a slotted track 11 adapted to receive a matching member forming part of the robot arm (not shown) , as shown in Fig. 3, or any similar attachment means.

[0009] For lifting a piece of cloth as shown in Figs. 2 and 3, vacuum has to be applied. Obviously too little vacuum would not hold the cloth while excessive vacuum - may cause the edges of the cloth to double back causing unwanted folds or harm this cloth in any other way. Consequently, the vacuum has to be carefully controlled in a manner which is self-urxierstood to persons versed in the art.

[0010] With a vacuum of 15 cm of mercury, i.e. about l/5th of an atmosphere, and an airflow of about 100 1/m per minute through denim fabric a gripper of a kind shown in Fig. 1 that measures 10-15 cm in length, 3 cm across, 3 cm in height and in which the larger holes measure 6 mn , and the smaller ones 3mm in diameter, will lift about 240 g which is quite adequate when bearing in mind that a front panel of a pair of trousers weighs about 115g and a pocket only 15 g. Obviously the vacuum requirements will change with-the nature of the cloth.

[0011] During operation the tubular holes 4 and 6 apply the vacuum and allow the gripper to lift the cloth while minimizing the pull on the table. The rubber collars also minimize the tendency of the cloth to slide away to the side. The auxiliary smaller holes 6 serve to support the edge of the cloth which would other-wise tend to hang down and double back over the larger holes.

[0012] Studs 8 serve essentially to keep the tubular rubber rims a bit above the cloth when making a pick-up. This allows the gripper to rest on studs 8 while the vacuum sucks the cloth up from the table.

[0013] An individual gripper according to the invention having one or more holes may be used singly or be assembled in arrays to lift larger parts. In either case the shape and design of an individual gripper may be changed to fit a particular part of a garment. In case of gripper assemblies a plurality of gripppers are assembled in a frame so that the edges of the processed cloth that is to be lifted will be under control. A gripper frame may also hold gripper configurations for several different parts used in a series of operations. In such a case vacuum will be applied in each operation selectively only to those grippers which have to operate during a particular stage.

[0014] Figs. 4 to 9 show several operational-stages of noving a cloth with the aid of a robot fitted with a gripper according to the invention. In Fig. 4 a piece of cloth 13 rests in proper position on a table 14 ready for pick-up. In Fig. 5 a gripper 15 of the kind shown in Fig. 1, mounted at the end of an arm 16 of a robot is caused to bear on cloth 13 while vacuum is applied. In consequence, cloth 13 is attracted to the gripper 15 and lifted from table 4 as shown in Fig. 6. In Fig. 7 the cloth is transported to another working table 17 fitted with a sewing machine symbolized by foot 18 and needle 19. In Fig. 8 the cloth has been put on table 17 in proper position with respect to the sewing machine 18, 19. When vacuum is released and the gripper removed from table 17, cloth 13 is left on the table ready for processing as shown in Fig. 9.

[0015] Fig. 10 shows diagrammatically a gripper array for a trouser panel in which a plurality of gripper modules of the kind shown in Figs. 1 to 3 is mounted on a frame.

[0016] As shown, a frame 20 is mounted on a robot arm 21 and carries a plurality of gripper modules 22 each fitted with vacuum hoses 23 connected to a central vacuum tube leading to a vaccum pump (not shown) . The assembly is suitable, for example, for lifting a trouser panel.

Claims

1. A gripper for moving material in automatic sewing of garments, charachterized by a body with at least one operative face and having an inner hollow space, at least one opening in said operative face leading to said hollow space, at least one stud on each of the operative faces projecting slightly above said opening (s), and ducting means for connecting said hollow space to air pumping means adapted to establish at will a reduced pressure within said hollow space.

2. A gripper according to Claim 1 ch_arachterized in that said body is in the form of a hollow box.

3. A gripper according to Claim 1 charachterized in that said body comprises a distributor duct and at least one bore leading therefrom to said operative face.

Drawing