GB2096106A - A gripper for removing individual articles from a stack - Google Patents

Abstract

A gripper mechanism comprises two tip-like bits (11), one of the bits (11) being attached directly to an upright (2), the other being carried on one arm of a two-armed lever (4) pivotally mounted on the upright (2). One arm (6) of the lever (4) is connected by a tension spring (7) to the upright (2). The bits (11) are closed to fold and grip the topmost textile piece from the stack (10) by the downward pressure of spring (17) acting via roller (18). The bits (11) are opened by energising solenoid (8) to raise roller (18). The textile piece stack is supported on foam rubber so that the bits (11) can be more easily forced into the stack. The gripper mechanism is carried on a movable frame (1). <IMAGE>

Description

SPECIFICATION A gripper device for removing individual articles, more particularly of textile material, from a stack thereof This invention relates to a gripper device for removing and subsequently positioning individual articles of substantially flat, flexible material from the top of a stack thereof. The device is particularly suitable for handling individual articles of textile material and can be used for automation in textile factories, for example, of the clothing industry.

Devices for the singling out of textile articles from a stack, followed by their positioning, are known. They include devices in which gripper elements grip the top textile article, which they lift, convey, position and then release. The grippers are attached to a transport frame and move together therewith. The construction of the gripper elements is the decisive factor in the quality of singling out.

If the various methods were to be subdivided in accordance with their operating principles, a group might be formed which operates on the principle "form a fold-hold on to the fold".

German Offenlegungsschrift 2108401 discloses a gripper head which operates on the principle stated. It comprises a plurality of resilient gripper fingers disposed at equal distances in a circumferential direction. The gripper elements have blunt end faces by which they are applied to the stack. At the start the elements are expanded apart. During the gripping operation the gripper elements are moved simultaneously radially inwards under pressure on to the stack. Folds are formed and clamped tight between the closed gripper elements. The effectiveness of the gripping is greatly dependent on the particular properties of the material, since the folds must be formed by the blunt end faces of the gripper elements, which are moved inwards under pressure parallel with the stack surface.

It is an object of the invention to provide a device for the singling out of individual articles, more particularly of textile material, in which the grippers are more adaptable to different qualities of the material.

Accordingly, the present invention consists in a gripper device for removing and subsequently positioning individual articles of substantially flat, flexible material from the top of a stack thereof, comprising a transport frame, power and control means for moving and positioning said transport frame, an upright supported in said frame and provided at its lower end with a gripper mechanism comprising two gripper elements, and actuating means mounted on the upright for operating the gripper mechanism, the two gripper elements terminating downwards in tip-like bits disposed close beside one another, one of said bits being attached to the body of said upright and the other to a finger which is pivotally connected to the upright above and laterally of said one bit.

The present invention also consists in a gripper device for removing and subsequently positioning individual articles of, for example textile material, from the top of a stack thereof, the device comprising a transport frame and power and control means for moving and positioning the transport frame, one or more grippers attached by means of an upright to the transport frame and each having two gripper elements, actuating means for moving the gripper elements, for example, in the form of driven tappets, an inclined plane and a return spring, and stack-retaining and holdingdown means, characterized in that the two gripper elements terminate downwards in tiplike bits disposed close beside one another, one said bit being attached to the upright of the gripper and the other to a finger which is pivotally connected to the upright above and laterally of said one bit, the stack being borne on a soft support, for example a foam rubber sheet.

The tip-like profiles can be vertically bisected pyramidal, conical or spherical tips.

The arrangement of the invention basically also operates on the principle "form a foldhold on to the fold". Its gripping elements are even better adapted to the gripping operation.

When applied to the stack, the gripper forces a conical funnel into the stack. This is facilitated by an inclination at the foot of the upright, the tip-like bits and the soft stack support (foam rubber sheet). The top part of the stack is held tight by said foot. The fold is formed and clamped tightly by the finger. The formation of the fold is substantially assisted by three features: the funnel, the movement of the finger (from top to bottom, and from outside to inside) and the tip-like bits. Together with the adjustability of the outermost expanded distance of the finger of the foot, the gripping operation is very reliable even with different qualities of material.

In order that the invention may be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example an embodiment thereof, and in which: Figure 1 is an overall view of the gripper device according to the invention, and Figures 2 to 4 show different constructions of the tip-like gripper bits.

An upright 2 of flat material is attached to a transport frame 1. Known power and control means (not shown) are provided for moving and positioning the transport frame 1, for example in accordance with a program. The upright 2 stands substantially perpendicularly over the top surface of a stack 10 of the textile parts to be singled out. At its foot 3 the upright 2 terminates in the direction of the right-hand narrow side (as viewed in Fig. 1).

A substantially mushroom-shaped finger 4 is situated on one broad side of the upright 2.

The stem of the finger 4 is substantially horizontal. Disposed at the end of the stem is a pivot 5 with pivot axis perpendicular to the broad side. The finger 4 is pivotable about this axis. The cap underside of the mushroomshaped finger lies substantially parallel with the right-hand narrow side of the upright 2.

This underside is adjusted above the pivot 5 by means of a substantially horizontally disposed spacing screw 9 to a determined distance from the upright, in dependence on the properties of the individual textile part in the stack 10.

Tip-like bits 11 are attached to the end of the base 3 and to the opposite end of the finger 4 to form a gripper. They may be vertically bisected pyramidal 12, conical 1 3 or spherical tips 14 (Figs. 2 to 4). When the gripper is closed (as described hereinbelow), they are substantially flush with one another.

The stack 10 rests on a support 15, for example a foam rubber sheet, on a stacking table 1 9 and can be limited by abutment 20.

An arm 6 extends substantially vertically upwards from the stem of the finger 4. It terminates at the top end obliquely in the direction of the right-hand narrow side of the upright 2. The arm 6 is engaged by a tension spring 7 which pulls the finger against the spacing screw 9. A solenoid 8 is attached to the upper part of the upright 2. Its armature is connected to a slide 1 6 which is forced downwards by a gripper spring 1 7 in the deenergized condition of the electro-magnet 8. A pressure roller 1 8 is attached to the free end of the slide 16. The pressure roller 18 presses against the oblique edge of the arm 6 of the finger 4 and closes the gripper when the solenoid 8 is in the de-energized condition.

Upon energization of the solenoid 8 the gripper is opened.

Claims (6)

1. A gripper device for removing and subsequently positioning individual articles of substantially flat, flexible material from the top of a stack thereof, comprising a transport frame, power and control means for moving and positioning said transport frame, an upright supported in said frame and provided at its lower end with a gripper mechanism comprising two gripper elements, and actuating means mounted on the upright for operating the gripper mechanism, the two gripper elements terminating downwards in tip-like bits disposed close beside one another, one of said bits being attached to the body of said upright and the other to a finger which is pivotally connected to the upright above and laterally of said one bit.

2. A gripper device as claimed in Claim 1, wherein said finger is constructed as a twoarmed lever carrying at its one arm said other bit and being connected at its other arm to a tension spring which urges the lever to pivot so as to cause said one arm with said other bit to move away from said one bit and to open the gripper mechanism.

3. A gripper device as claimed in Claim 2, wherein the other arm of said lever is provided with an oblique surface which is engageable by a push-rod axially movable by means of a solenoid mounted on the upright to cause the lever to pivot against the force of said spring and to close the gripper mechanism.

4. A gripper device for removing and subsequently positioning individual articles of, for example textile material, from the top of a stack thereof, the device comprising a transport frame and power and control means for moving and positioning the transport frame, one or more grippers attached by means of an upright to the transport frame and each having two gripper elements, actuating means for moving the gripper elements, for example, in the form of driven tappets, an inclined plane and a return spring, and stack-retaining and holding-down means, characterized in that the two gripper elements terminate downwards in tip-like bits disposed close beside one another, one said bit being attached to the upright of the gripper and the other to a finger which is pivotally connected to the upright above and laterally of said one bit, the stack being borne on a soft support, for example a foam rubber sheet.

5. A gripper device as claimed in any of the preceding Claims, wherein the tip-like bits are vertically bisected pyramidal, conical or spherical tips.

6. A gripper device, substantially as herein described with reference to and as shown in the accompanying drawings.