FR2554783A1 - PROCESS FOR FORMING THE U-BOTTOM - Google Patents

Abstract

1. Process for forming the bottom of a sachet of flexible synthetic material from a cushion (1) of synthetic material filled with liquid, and for imparting stability to it, in which the filled cushion (1) is disposed on a support beam (6) of width less than the width of the cushion in such manner that at least one of the lower corners (7, 8) of the cushion protrudes beyond the beam, tending downwards, characterised in that a gripper (9, 10) is applied to each side of the beam, the exerted pressure force of which gripper expelsthe liquid contained in the said corner or corners, in that welding is effected along at least one line which will impart stability to the sachet, thus forming at least one lug, each corresponding to a corner (7, 8).

Description

The subject of the present invention is a process for forming

  sea the bottom of a bag of soft synthetic material from a

  cushion made of synthetic material filled with liquid and for

  stability. The invention also relates to the bags obtained according to this method and the welding and cutting unit for

its implementation.

  When producing containers made of synthetic

  a flexible problem, one of the problems posed is that of the stability of the bag, obtained by a specific conformation of the bottom of the bag

  to allow its installation on a flat surface.

  Multiple structures have been proposed and give

  tisfaction. For example, as in the French application

  - 18358 in the name of the plaintiff, the bottom of the bag is

  formed in W by folding the plastic film before replacing

  pleating. In the same way the French patent 71 - 20879 proposes to conform the bottom by welding and cutting angles forming

  ears after folding the bottom. In these achievements it is essential

confirm that the bag is empty.

  If the W-bottom allows continuous machining

  horizontal path, the structure of patent 71 - 20879 does not

  can be obtained continuously.

  In addition, the two proposed projects are

  made from empty bags, at a given stage of

their conformation.

  The need is therefore felt for a method for continuously producing flat-bottomed sachets, with the same advantages as the W bottom, while allowing intervention on a filled bag, in the intermediate cushion state, more

  particularly by a method of vertical traverse,

  lending to a succession of cushions from a continuous coil

of movie.

  According to the invention, this result is otenu with a process for forming the bottom of a plastic bag

  flexible from a synthetic cushion filled with

  quide and to give it stability, characterized in that it consists in arranging the filled cushion on a support beam of width less than the width of the cushion so that the two lower corners of the cushion protrude with respect to the

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  Beam tending downward, which is applied to each side of the beam a clamp whose pressure effect exhaled the liquid contained in the two aforementioned corners, that is welded

  along two lines that will give stability to the bag, determine

  thus two ears corresponding to the corners. Although it is particularly suitable for machines with vertical tracking, this method can also be transposed

  machines with horizontal tracking.

  The invention will be better understood by means of the

  Hereinafter, a nonlimiting mode of implementation of the method is described with reference to the appended drawings in which:

  FIG. 1 illustrates the positioning of the cushion

fold on the support beam,

  FIG. 2 illustrates the clamping operation, which

  hard and cutting, - Figure 3 shows a schematic section of the

welding and cutting pliers.

  Reference will be made in the following to a vertical path, but it should be understood that the method is perfectly adaptable to a horizontal path as described, for example

  in the French patent application 80 - 13039 in the name of the

  dant. The problem posed consists, in the case of the vertical path, to give stability and shape to the bottom of a cushion (1) filled with liquid (2). The cushion is obtained from a film wound on a mandrel, and comprises three weld lines

  (3, 4, 5). This is in itself well known to those skilled in the art.

  To conform the bottom, it is provided according to the invention to arrange the cushion (1) on a support beam (6) of any section, for example rectangular or trapezoidal, the

  small base pointing upwards.

  In the case of a vertical path, the length of this beam must be simply sufficient to receive a bag. For a horizontal path, the beam may be longer and serve as a guide and support for the rosary sachets

during part of their journey.

  In the vertical path, this beam will be disposed, for example just after the cutting station of the cushions in individual elements from the continuous coil, so as to drop them from a height of a few centimeters on the support beam to clearly mark the corner edges. This station can also be provided in operation during filling, making

mount the beam to the cushion.

  Indeed, the width of the beam, is chosen such that, when it is centered, the filled cushion has two corners (7,8) projecting from the beam and tending downward, by simple gravity. That's what was schematized at

Figure 1.

  Referring now to Figure 2. The cushion is still in the position of Figure 1, is applied on each side of the beam (6) a welding pliers (9,10) which has a dual function: - Exercise a pressure on the corners (7,8) so as to drive the liquid contained thereinto the interior of the cushion and apply the corners against the side walls of the beam; - determine a weld line at the highest level

  high possible with respect to the upper plane of the beam.

  At this stage, the cushion is therefore with a base having two linear edges connected by two indefinite outlines

  curved configuration when the cushion is placed vertically

  tically on a flat surface, the two edges extending

  by two ears corresponding to the corners (7,8).

  It is possible to leave these ears as they are.

  It is also possible to wind them by a

  rotary gripper device subject of a joint application

by the plaintiff.

  Advantageously, these ears will be cut by blades integrated in the welding tongs and severing said ears,

  just after the welding operation or even during the filling.

  A complete clamp ensuring all operations therefore comprises: - a bearing surface (11) for pressing the wedge against the beam, - a welding member (12) - a blade (13) movable in the clamp It has been presented to Figure 3 a variant in which

  the welding head (15) and the blade (16) are integrated into the

  tre (6 '). The clamp (9 ') therefore remains, but its only role is

  to apply the corner against the support.

  It is possible to provide on the beam or the clamp, beneath the cutting blade, a bearing surface (14) made of a material which is less hard than the beam or the pliers in order to avoid bursting the corners before welding. Similarly, to prevent the liquid driven corners (7 is pushed down, it is important that the app surface of the clamps (9,10) is in all cases larger than the corners

  (7,8) so that they are solicited on all

area.

2554783

Claims (5)

CLAIMS.   Method for forming the bottom of a bag of flexible synthetic material from a cushion of synthetic material filled with liquid and to give it stability, characterized in that it consists in arranging the cushion (1) filled on a support beam (6) with a width less than the width of the cushion so that the two lower corners (7,8) of the cushion project over the beam by tending downwards, which is applied to each side of the beam a clamp (9,10) whose gripping force exerted flush the liquid contained in the two aforementioned corners, which is welded along two lines which will give stability to the bag, thus determining two ears corresponding to the corners (7,8).   I. Method according to claim 1, characterized in that the two ears corresponding to the corners (7,8) are cut by   a blade integrated into the welding pliers.   3. Method according to any one of claims 1 and 2,   characterized in that the filled cushion falls on the beam (6).   4. Method according to any one of claims I to 3,   Characterized in that the support beam (6) rises towards the cushion during the filling thereof to form the lugs (7,8) and that the cutting and welding thereof are performed during filling.   5. Welding and cutting unit for the implementation of the   method according to any one of claims 1 to 4   characterized in that it comprises: - a gripper (9, 10, 9 ') - a teted-e welding a cutting blade - a support beam 6. A unit according to claim 5, characterized in that the head of welding (15) and the blade (16) are integrated with the beam (6).   7. Unit according to any one of claims 5 and 6   characterized in that the beam (6,6 ') or the pliers (9,10,9') have a bearing surface (14) of less hard material than the beam or the clamp.