EP0347323B1 - Method and apparatus for automatically gripping two adjacent corners of a flat cloth - Google Patents

Abstract

The invention relates to a method for automatically gripping two adjacent corners of a flat rectangular cloth and an apparatus for carrying out the method. Any zone of the flat cloth and a first corner are grasped (at 5). Subsequently, the first corner is subjected to a relative movement in relation to the grasping zone in such a way that at least one of the two corners adjacent to the first forms a low point. Finally, the corner which is at the low point is grasped (at 12) and then the grasping zone is released.

Description

The present invention relates to a method and an automated machine for gripping two adjacent corners of a flat cloth. Such a machine is particularly suitable for the work of a laundry after the washing phase and before the finishing phase of the flat linen, phase for which it is necessary to present the flat linen gripped by its corners. Indeed, the finishing phase consists in engaging the washed and wrung flat linen stretched between two of its adjacent corners in a calendering machine which then entails it to dry it, iron it, and fold it automatically.

In practice, finding the corners of a flat cloth requires manual intervention, which is very expensive in human resources and, consequently, increases the fixed costs of laundries. An automated gripping system for flat towels has already been described in document FR-A-2 336 510 (76 38 113). The system proposed in this document requires the entry of the flat linen successively at four points including a first arbitrary point of the flat linen, a first corner of the flat linen, which constitutes the lowest point of the flat linen suspended from the first arbitrary point, the corner flat linen diagonally opposite this first corner, and a second corner of flat linen, adjacent to the first. On the other hand, the fact that the flat linen is stretched between the first corner and the diagonally opposite corner leads to a machine of considerable bulk, since the flat linen is thus stretched along its diagonal, which is the greater distance between two points of a flat cloth. Finally, this system uses batteries of detectors to find the second corner, and the closing of the clamp intended to grip the flat linen must therefore be able to be controlled at a non-fixed point, which is technically more difficult to achieve than a system where the clamps are closed in a fixed place.

The document JP-A-63 139863 (which corresponds to EP-A-0 272 368) relates to a system for gripping a linen in which, during a first step, the linen is gripped at any point. Then, in a second step, the laundry is gripped by a first corner previously detected during an upward movement of the laundry; any point entered in the first step is then released so that the laundry hangs from the first corner entered in the second step.

In a third step, the laundry is gripped at a second corner, diagonally opposite the first gripped corner, and detected as the lowest point during an upward movement of the laundry driven by the first corner.

In a fourth step, the laundry is pulled, along a substantially vertical path, by the first corner, which drives, by pulling along the diagonal of the laundry, a clamp clamping the second corner.

Finally, a third adjacent corner is detected, at the two diagonally opposite corners already entered, and this third corner is entered.

Then, depending on whether one wishes to hold the laundry along a long side or a short side, one releases one of the diagonally opposite corners previously gripped.

Such a system also requires the entry of flat linen successively at four points. It is therefore relatively complicated and has drawbacks similar to those mentioned in connection with FR-A-2 336 510 previously.

The present invention overcomes the disadvantages cited above. In fact, the method presented makes it possible to grasp two adjacent corners of a flat linen by gripping it successively only in three places, including any zone. It also avoids taking the corner of the flat linen diagonally opposite the first corner and stretching the flat linen between these two corners, thereby reducing the size of the machine. Finally, the method presented makes it possible to bring the corners to be grasped always in the same places, which facilitates their gripping.

More specifically, the method according to the invention making it possible to grasp two adjacent corners of a flat linen is characterized in that, in a first step, any zone of said flat linen is grasped by a gripping means, said zone having a reduced area around a point, the grasped flat linen is suspended from said gripping means by allowing it to hang under the effect of gravity, the lowest point of said flat linen is identified and said lowest point is grasped, which constitutes the first corner of the flat linen, using a gripping means.

In a second step, a relative movement of the first corner thus grasped relative to the arbitrary zone for gripping the flat linen is ensured by translation, so that at least one of the two corners adjacent to the first constitutes an apparent low point of the linen dish held by any input area and said first corner; that, in a third step, one grasps said apparent low point, which constitutes a corner adjacent to the first corner, and that, in a fourth step, one releases said entry zone.

According to a preferred mode of implementation in the second step, the flat linen is untangled using a means which shakes it from the gripping and gripping means by which it is suspended.

After the second step, to separate a point apparent bottom of the flat linen from the rest of said flat linen, said flat linen is positioned above a separation means, the any gripping area and the first corner of said flat linen being situated on either side of said separation means , and ensuring a relative rise of the separation means with respect to the flat linen between the two apparent low points of said flat linen; the any input zone of said flat linen and the first corner of the flat linen are brought closer, until bringing the apparent low point which, on a small side of the flat linen, is adjacent to the first corner, on a chosen vertical; for gripping a corner consisting of an apparent low point of the flat linen gripped by one or more gripping means, the flat linen is brought to the right of a centering means; moving the gripping means or means away from said centering means, the flat linen being forced to move in line with said centering means; detecting the passage, to the right of said centering means, of the point which, initially, constituted said apparent low point of the flat linen; and then stops the movement of said flat linen to grasp the point thus detected; before entering the detected apparent low point, the flat laundry corner corresponding to said low point is placed on a suction element by means of a jet of blown air; the suction element is brought to the right of a means which detects the presence of the wedge pressed against said suction element, the movement of said suction element is stopped and said corner is grasped.

The invention also relates to a machine for implementing the above-mentioned method.

Said machine comprises a gripping means for gripping a flat cloth in any zone, a means for raising said flat cloth after it has been gripped, a detector for signaling the passage from the lowest point of said flat cloth of a predetermined level and a gripping means for gripping the corner of the flat linen formed by said lowest point, means for moving relative to each other the gripping and gripping means and means for gripping a second corner of said adjacent flat linen audit first corner.

The machine comprises a means for shaking the flat linen, said means acting on the means for gripping and gripping the arbitrary zone and the corner by which said flat linen is suspended, a guide for separating the two apparent low points of the suspended flat linen , a displacement means for positioning the flat linen suspended above said guide, said guide being substantially parallel to the movement of the gripping and gripping means; for at least one of the stations where a corner is grasped, it comprises a centering means and a displacement means forcing the flat linen to move in line with said centering means and at least one detector for signaling the presence of the flat linen to the right of said detector, a suction ramp and an air blowing nozzle, the relative position of the ramp and the nozzle being modifiable to bring the ramp opposite the nozzle when the corner is grasping has been detected, a detector for detecting the presence of the wedge on the suction ramp and means for bringing said suction ramp in line with said detector; it also includes conveyor rails, conveyor clamps comprising a gripping means, each conveyor clamp moving on one of said rails by means of two wheels integral with said clamp, said wheels rolling on the rails on either side of said rails; the conveyor rails are telescopic to allow adjustment of the machine for different dimensions of flat linen; the gripping gripper gripping means can pivot relative to the grippers.

• la figure 1 est une vue schématique d'un mode de réalisation suivant l'invention,
• la figure 2 est une vue schématique du mode de réalisation de la figure 1 sur laquelle ont été représentés plusieurs linges plats en cours de traitement.

Other objects, characteristics and advantages of the invention will appear more clearly with the aid of the following explanatory description, made with reference to the appended schematic drawings, of a currently preferred embodiment of a machine according to the invention, given by way of example only. In these drawings:

• FIG. 1 is a schematic view of an embodiment according to the invention,
• Figure 2 is a schematic view of the embodiment of Figure 1 on which have been shown several flat towels during treatment.

Referring to the drawing, it can be seen that the machine comprises a suction cup (4) in which a depression is created for gripping by suction a flat cloth in a carriage (1) which contains several flat cloths. Then, an arm (3) integral with the suction cup (4) and moving in a vertical translation relative to a stationary frame (2) raises the flat linen thus seized up to a fixed height greater than the length of the diagonal of the flat linen.

Just below this height is located a rail (6) horizontal and straight over a distance greater than the length of the diagonal of a flat linen from the frame (2). Two identical longitudinal plates (7) and (8) having a common edge parallel to their axes, their outer edges forming a notch at one of their ends relative to the common inner edge, and whose section in a vertical plane perpendicular to their axis form a "V", are arranged parallel to the rail (6), at a height slightly lower than this rail (6), the notches being turned towards the suction cup, so that the suction cup is in the same vertical plane as their common edge, at a distance from the vertical ascent of the suction cup such that the suction cup can rise in the notch of the two plates without hanging them. The two plates can pivot simultaneously around the outer edge of the plate (8) which is closest to the rail (6). A detector (9) is placed vertically above the notch, slightly below it to detect the presence of the flat linen. A horizontal suction ramp (10) is placed in the vertical plane formed by the vertical passing through the notch and the common edge of the two plates, between the detector and the notch; a blowing nozzle (11) is placed in the horizontal plane of the ramp (10), this nozzle being articulated on a pivot integral with the ramp (10), so that in the open position, the nozzle (11) makes a 90 ° angel with the ramp and in the closed position, the nozzle and the ramp form a clamp closing on the vertical of the notch. Is placed in the vertical plane of the ramp (10) slightly below the ramp (10), a horizontal rail (13), which moves away from the suction cup (4) and the rail (6), the angle between the two rails being acute.

A clamp (5) circulating on the rail (6) grips the flat laundry below the suction cup and the vacuum inside the suction cup (4) is removed. The clamp (5) moves away from the suction cup on the rail (6), the flat linen lying on the plates (7) and (8); the passage from the bottom point of the flat linen, which constitutes a corner, is detected using the detector. The advance of the clamp (5) is stopped on the rail (6) and the nozzle (11) is brought opposite the ramp (10). A clamp (12), circulating on the rail (13), grasps the corner held by the ramp (10) and the nozzle (11). The nozzle moves to the open position, the two plates (7) and (8) pivot down, thereby releasing the flat linen carried by the clamps (5) and (12) on their respective rail (6) and (13) .

The rail (13) is subjected to a torsion of 180 ° relative to its axis. When the two rails (6) and (13) are distant by a distance of the order of a half diagonal of flat linen, the rail (13) becomes parallel to the rail (6) on a portion (28) of the order of one meter. Then the two rail portions (29) and (26) come together at a distance of a few tens of centimeters and the rails (6) and (13) become parallel again on their portions (30) and (27). Is placed between the two rails before their approximation a separation guide (14) symmetrical with respect to a vertical plane perpendicular to the direction of movement of the flat linen; the distance from this plane to the rail (6) being of the order of fifty centimeters. This guide is formed of two symmetrical left plates and joined in their upper edges located in the vertical plane of symmetry; at the beginning of the guide, the upper edge of the two plates and located at a vertical distance from the rail (6) greater than a small side of flat laundry to approach vertically from the rail (6) while remaining below, the lower edge merging at the start of the guide with the upper edge then moving away from the vertical plane of symmetry while remaining horizontal, following a concave curve, and the first part of the guide describing a concave surface between the two edges. The second part of the guide is located between the portions (29) and (26) of the rails (6) and (13), the upper edge of the plates remaining horizontal in the vertical plane of symmetry, the lower edge remaining in one plane. horizontal and following a convex curve then concave to approach the vertical plane of symmetry, the plate describing a convex surface between the two edges. Between the rail portions (30) and (27) of the two rails (6) and (13), four plates ((15), (16)) and ((17), (18)) are placed, two to two identical to the plates ((7), (8)). The plates ((15), (16)) are placed between the two rails (6) and (13) parallel to these two rails so that the outer edge of the plate (16), closest to the rail (6) , or in the extension of the upper edge of the guide (14), the notch of the two plates ((17), (18)) being on the side of the guide. These plates ((15), (16)) can pivot around the outer edge of the plate (16). The plates ((17), (18)) are placed parallel to the rails (6) and (13) on either side of the rail (6) so that the outer edge of the plate (17), located between the of them rails (6) and (13), either in the extension of the upper edge of the guide (14), the notch of the two plates ((17), (18)) being on the side of the guide. These two plates ((17), (18)) can pivot around the outer edge of the plate (17). A detector (19) is placed on a support (20) vertical to the notch of the plates ((15), (16)), slightly below the latter to detect the presence of the flat linen. A suction ramp (21) is placed, integral with the support (20), horizontal in the vertical plane formed by the vertical passing through the notch of the plates ((15), (16)) and the common edge of the two plates (( 15), (16)), between the detector (19) and the notch; a blower nozzle (22) is placed in the horizontal plane of the ramp (21), this nozzle being articulated on a pivot integral with the ramp (21), so that in the open position, the nozzle (22) makes a 90 ° angle with the ramp (21) and that in the closed position, the nozzle and the ramp form a clamp closing on the vertical of the notch. The support (20) can move on a rail (23) fixed to the ground perpendicular to the axes of the plates ((15), (16)), so that the detector (19) is located, after a chosen translation, vertical to the notch of the plates ((17), (18)). A horizontal rail (25) is placed slightly below the ramp (21), perpendicular to the axes of the plates ((15), (16)) and ((17), (18)).

The two clamps (5) and (12) are advanced on their respective rails, the clamp (12) undergoes a 180 ° reversal which positions it under the rail (13) then the two clamps being separated by about a half diagonal of flat linen, this forms two apparent low points that the guide (14) separates. The clamps (5) and (12) then advance, leaving the flat laundry to drag on the plates ((15), (16)) and ((17), (18)); depending on whether you want to grasp the long side or the short side of the flat linen, by moving the support (20), you will place the detector (19), the ramp (21) and the nozzle (22) respectively below the plates ((15), (16)) or below the plates ((17), (18)). The detector (19) then detects the passage from the low point that we want to capture and we stop both simultaneously pliers; the nozzle (22) is brought opposite the ramp (21), thus grasping the corner of the hanging sheet. A clamp (24), moving on the rail (25), grasps the desired corner. The clamp (5) then releases the flat linen and the two clamps (12) and (24) entrain the flat linen on their respective rails, the two corners are then ready to be engaged.

FIG. 2 represents several flat cloths at different stages of the general treatment. The flat linen (31) is located at the station where it is grasped at any point by means of a suction cup. The flat linen (32), pulled by the clamp (5), rests on the plates (7) and (8); the ramp (10) and the nozzle (11) are in the closed position and the clamp (12) grasps the flat linen (32) at the first of its corners. The flat linen (33) illustrates the appearance of two low points when the clamps (5) and (12) are in the separated position on their respective rails. The flat linen (34) passes over the guide (14), which separates the two visible low points of the flat linen. Next, the flat linen (35) represents the gripping of the corner of the flat linen adjacent to the first corner gripped by the clamp (12) on the short side of the flat linen, the ramp (21) and the nozzle (22) being in the closed position. . Finally, the flat linen (36) is taken to the feeder, gripped by two of its adjacent corners.

Claims (16)

1. Process for the automated gripping of two adjacent corners of a flat rectangular piece of linen, characterised in that in a first stage an arbitrary region of said flat linen is grasped by a grasping means (5), said region having a surface constrained about a point, the grasped flat linen is suspended from said grasping means (5) by letting it hang under the effect of its weight, the lowest point of said flat linen, which is a first corner of said flat linen, is located and said lowest point is grasped with the aid of a gripping means (12); in that the relative displacement, with respect to the arbitrary grasping zone of the flat linen, of the first corner thus grasped is ensured in a second stage so that at least one of the two corners adjacent to the first consitutes an apparent low point of the flat linen held by the arbitrary grasping point and said first corner; in that in a third stage said corner adjacent to the first corner, which constitutes said apparent low point, is grasped, and in that in a fourth stage said grasping point is released.
2. Process according to claim 1, characterised in that the flat linen is straightened-out in the second stage with the aid of means which shake it from the gripping means (12) and grasping means (5) by which it is suspended.
3. Process according to claim 1 or 2, characterised in that the flat linen is positioned above a separation means (14) in order to separate an apparent low point of the flat linen from the rest of said flat linen after the second stage, the arbitrary grasping zone and the first corner of said flat linen being situated one on either side of said separation means (14), and a gradient in the separation means (14), with respect to the flat linen, is provided between the two apparent low points of said flat linen.
4. Process according to one of claims 1 to 3, characterised in that the arbitrary grasping point of said flat linen and the first corner of the flat linen are brought together until the apparent low point which, on a short side of the flat linen is adjacent to the first corner, is brought onto a selected vertical.
5. Process according to one of claims 1 to 4, characterised in that to grip a corner which is an apparent low point of the flat linen grasped by one or several gripping means (5, 12) the flat linen is brought at right angles to a centering means (7, 8; 15, 16); one or more gripping means (5, 12) of said centering means (7, 8; 15, 16) is moved away, the flat linen being forced to move at right angles to said centering means (7, 8; 15, 16); and the passage of the point, which initially constituted said apparent low point of the flat linen, at right angles to said centering means (7, 8; 15, 16), is detected; the movement of said flat linen is then checked in order to grasp the point thus detected.
6. Process according to claim 5, characterised in that the corner of the flat linen corresponding to said low point is laid on a suction element (10, 21) by means of a blown air jet (11, 22) before the detected apparent low point is grasped.
7. Process according to claim 6, characterised in that the suction element is brought at right angles to a means which detects the presence of the corner laid on said suction element, and in that the movement of said suction element is stopped and said corner is grasped.
8. Machine for putting into operation the process according to claim 1, characterised in that it comprises a grasping means (5) for grasping a flat piece of linen in any region whatsoever, a means for lifting said flat linen after being gripped, a detector (9) to indicate the passage of the lowest point of said flat linen at a predetermined level, and a gripping means (12) for grasping the corner of the flat linen formed by said lowest point, a means for moving the grasping means (5) and the gripping means (12) with respect to each other, and a means (24) for grasping a second corner of said flat linen adjacent to said first corner.
9. Machine according to claim 8, characterised in that it comprises a means for shaking the flat linen, said means acting on the grasping means (5) and gripping means (12) of the arbitrary zone and of the corner by which said flat linen is suspended.
10. Machine according to claim 8 or 9, characterised in that it comprises a guide (14) for separating the two apparent low points of the flat suspended linen, a displacement means for positioning the flat suspended linen above said guide (14), said guide (14) being substantially parallel to the displacement of the gripping means (12) and grasping means (5).
11. Machine according to one of claims 8 to 10, characterised in that it comprises a centering means (7, 8) and a displacement means forcing the flat linen to move at right angles to said centering means (7, 8) for at least one of the positions where a corner is grasped, and at least one detector (9) for indicating the presence of the flat linen at right angles to said detector (9).
12. Machine according to one of claims 8 to 11, characterised in that it comprises a suction ramp (10) and an air-blowing nozzle (11) for at least one of the positions where a corner is grasped, the relative position of the ramp (10) and of the nozzle (11) being changeable to bring the ramp (10) opposite the nozzle (11) when the corner to is grasped has been detected.
13. Machine according to claim 12, characterised in that it comprises a detector for detecting the presence of the corner on the suction ramp (10) and a means for bringing said suction ramp (10) at right angles to said detector.
14. Machine according to one of claims 8 to 13, characterised in that it comprises conveying rails (6, 13 and 25), conveying clamps (5, 13 and 24) comprising a grasping means, each mobile clamp moving along one of said rails by means of two wheels integral with said clamps, said wheels rolling along the rails, one on each side of said rails.
15. Machine according to claim 14, characterised in that the conveying rails (6, 13, 25) are telescopic so as to allow adjustment of the machine for different dimensions of flat linens.
16. Machine according to claims 14 or 15, characterised in that the grasping means of the mobile clamps (5, 13, 24) can swivel with respect to said clamps.

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