Methods for automatically filling-inflating gas cushions, notably air cushions, for packaging and use thereof for filling and inflating cushions

Abstract

A machine for automatically inflating air cushions. The cushions have two plastic walls (21; 22) joined together around their periphery to define a closed space. The machine comprises a source of gas under pressure, and two jaws (1; 2) arranged such that they can move on a supporting structure. Each one of the jaws consists of a body (1; 3) each having a plane face (4; 10) of substantially the same shape and surface area, it being possible for the faces to mate against one another in order to clamp between them the walls (21; 22) of a cushion. Each jaw comprises an aspiration channel (6; 7) opening onto its planer face. A first jaw on the inside of its body has a hollow needle (5) able to move relative to the body and capable in a certain position of having its pointed tip outside of the surface of the plane face. A second jaw within its body has a heating element (18) capable, when the two jaws are clamping between them the two walls of a cushion, of heat-welding the two walls together over a certain proportion of their contacting surface.

Claims

1. A method for inflating a cushion comprising: clamping at least a first wall and a second wall of the cushion between a first terminal face of a first jaw and a second terminal face of a second jaw; axially moving a needle within a cylinder of the first jaw to perforate at least one of the first wall and the second wall of the cushion; aspirating gas through a first aspiration channel disposed within the first jaw adjacent to the first terminal face of the first jaw; aspirating gas through a second aspiration channel disposed within the second jaw adjacent to the second terminal face of the second jaw; injecting pressurized gas through the needle; and activating a heating element disposed within the second jaw to heat-seal the first wall to the second wall.

2. The method of claim 1, further comprising: axially moving the heating element relative to the second terminal face of the second jaw.

3. The method of claim 1, wherein injecting pressurized gas through the needle comprises: prior to aspirating gas through the first and second aspiration channels, injecting a first jet of pressurized gas through the needle to separate the first wall and the second wall; and while aspirating gas through the first and second aspiration channels, injecting a second jet of pressurized gas through the needle to inflate the cushion.

4. The method of claim 1, further comprising: separating the first and second jaws while aspirating gas through the first and second aspiration channels.

5. The method of claim 1, wherein axially moving the needle comprises axially moving the needle to perforate at least one of the first wall and the second wall adjacent a periphery of the cushion; and wherein activating the heating element comprises activating the heating element to heat-seal the first wall to the second wall along a line connecting two portions of the periphery of the cushion to form a triangular region.

6. The method of claim 1, wherein prior to clamping, the method includes: positioning the cushion between the first jaw and the second jaw, wherein the first wall and the second wall of the cushion are linked together about their peripheries to define a closed space.

7. The method of claim 6, wherein the closed space includes a quantity of air trapped between the first wall and the second wall.

8. The method of claim 6, wherein the first wall and the second wall are linked at a discontinuous weld zone formed within the peripheries of the first wall and the second wall, the discontinuous weld zone defining a space in communication with a remaining volume of the cushion.

9. The method of claim 8, wherein axially moving the needle comprises: axially moving the needle to perforate at least one of the first wall and the second wall within the discontinuous weld zone, wherein the needle includes an opening at a distal end of the needle.

10. The method of claim 8, wherein activating the heating element comprises: activating the heating element to heat-seal the first wall to the second wall within the discontinuous weld zone.

11. The method of claim 6, wherein the peripheries of the first wall and the second wall define a protuberance, and wherein an interior of the protuberance forms a portion of the closed space.

12. The method of claim 11, wherein axially moving the needle comprises: perforating at least one of the first wall and the second wall at the protuberance.

13. The method of claim 11, wherein injecting pressurized gas through the needle comprises: injecting pressurized gas through a lateral opening in a wall of the needle.

14. The method of claim 11, wherein activating the heating element seals the first wall to the second wall proximate the protuberance.

15. The method of claim 14, wherein activating the heating element seals the first wall to the second wall proximate the protuberance along a straight line to separate the interior of the protuberance from a general volume of the cushion.

16. A method for inflating a cushion comprising: positioning a cushion between a first jaw and a second jaw, the cushion including a first wall and a second wall linked together at their peripheries, at least one of the first wall and the second wall defining a preformed hole disposed therethough; positioning an outlet orifice of the first jaw adjacent to the preformed hole; aspirating gas through a first aspiration channel disposed within the first jaw adjacent to the first terminal face of the first jaw; aspirating gas through a second aspiration channel disposed within the second jaw adjacent to the second terminal face of the second jaw; injecting pressurized gas through the outlet orifice of the first jaw; and activating a heating element disposed within the second jaw to heat-seal the first wall to the second wall.

Description

(1) The invention will be better understood, its features and its advantages will appear more clearly, on reading the detailed description of forms of execution, given only as an example and made with reference to the appended drawings, in which:

(2) FIG. 1 represents a form of execution of the jaws of a machine according to the invention.

(3) FIG. 2 represents the jaws of FIG. 1 clamping the walls, plastic film, of an uninflated cushion.

(4) FIG. 3 represents the jaws of FIG. 1 during the piercing of the walls.

(5) FIG. 4 represents the jaws of FIG. 1 separated at the time of a first jet of air being used to unstick the two walls of plastic film.

(6) FIG. 5 represents the jaws of FIG. 1 separated, allowing the cushion to be inflated.

(7) FIG. 6 represents the jaws of FIG. 1 separated at the time of inflation of the cushion.

(8) FIG. 7 represents the jaws of FIG. 1 clamping the walls of the inflated cushion.

(9) FIG. 8 represents the jaws of FIG. 1 at the time of the heat-sealing of the walls.

(10) FIG. 9 represents the jaws of FIG. 1 separated at the time of the release of the cushion from the machine.

(11) FIG. 10 represents on a cushion a circular space defined by a discontinuous weld.

(12) FIG. 11 represents a protuberance relating to a particular shape of a cushion.

(13) In all of the figures, the same reference symbols will be used to indicate the same features.

(14) With reference to FIGS. 1 to 9, only the jaws of one machine have been shown, according to a form of execution of the present invention, for the inflation and filling of an air cushion, because all the other elements of the machine are known and within the scope of those skilled in the art. It has also been considered that the two walls of a cushion consist of two sheets of plastic film.

(15) As can be seen in FIG. 1, the two jaws 1 and 2 are mounted on the frame, not shown, of a machine according to the present invention. The jaw 1, mounted movably on the frame of the machine, consists of a cylinder 3, inside which a hollow needle 5 is placed that can move in the direction of the axis of the cylinder 3. Said needle 5 is moved, in the case shown, by a piston 9, but it could also be moved by an electromagnet or any other means. Between the needle 5 and the piston 9 a flexible pipe 8 is provided carrying pressurized air to the inside of the needle 5. The distal end of the needle has a point 15 of which the air outlet is obstructed, while behind the point 15 the needle comprises by two (or a different number) lateral openings 14, designed to inject the air into the cushion (see FIG. 5). The jaw 2 consists of a cylinder 11 retained movably on the frame, not shown. The cylinders 3 and 11 can move longitudinally so that their terminal faces 4 and 10 can come into contact (see FIG. 2). The cylinder 11 contains a cylindrical part 17 concentric with the cylinder 11. Inside said part 17 an electrical heating body 18 is placed powered by an electrical cable 19. At its near end of the cylinder 3 the cylinder 11 has a cavity 16 designed to receive the point 15 of the needle 5. The two ends of the cylinders 3 and 11 face to face have a ring of openings in communication with an aspiration/suction device respectively through aspiration channels 6 and 7 placed in the cylinders 3 and 11.

(16) A use of a machine according to the invention defined in claim 2 proceeds in the following manner:

(17) a) the two walls 21 and 22 of a cushion, uninflated, of any shape, for example square, round, having several pockets connected together, are inserted between the jaws 3 and 11 of the machine as shown in FIG. 1.

(18) b) The two jaws 1 and 2 are moved so as to clamp between their terminal faces 4 and 10 the two sheets of plastic forming the walls of the cushion (see FIG. 2).

(19) c) The needle 5 of the jaw 1 is moved longitudinally perforating the two walls 21 and 22 and placing itself in the cavity 16 of the jaw 2 (see FIG. 3).

(20) d) The two jaws 1 and 2 are moved away slightly and a jet of pressurized air is injected through the lateral openings 14 of the needle 5 so as to unstick the two films 21 and 22 forming the walls of the cushion (see FIG. 4).

(21) e) The two jaws are reclamped, then the aspiration device is activated in the channels 6 and 7, placed in rings about openings allowing the needle to pass, and keep the two walls 21 and 22 stuck to the ends of the cylinders 3 and 11. The pressurized air is injected into the cushion through the openings 14 inflating the latter (see FIGS. 5 and 6).
f) The jaws 1 and 2 are brought together clamping the two walls 21 and 22 between them while compressing the air contained in the cushion (see FIG. 7).
g) The cylinder 17 contained in the body 11 of the jaw 2 is moved so as to press on the periphery of the outlet orifice of the needle 5 of the body 3. The heating element 18 is activated, heat-sealing the two walls along a ring surrounding the hole of the needle 5 preventing the air from leaving the cushion (see FIG. 8).

(22) As can be easily seen in FIG. 8, the surface area of contact between the two jaws 1 and 2 is larger than the heat-sealed zone, therefore, when the jaws are separated to release the cushion from the machine, the zone 23 represents a ring where the two walls are not stuck, and will be separated from one another thus causing a reduction of the pressure in the cushion.

(23) In order to remedy this defect, provision has been made in another form of execution of the use of the machine to provide cushions having at least one location where the two walls are partly heat-sealed defining a space in communication with the rest of the volume included between the two walls. As is seen in FIG. 10, this space is circular, defined by circularly arcuate welds. But this space could have another shape, for example polygonal, square, triangular, the only condition and that the weld line is not continuous so as to remain in communication with the rest of the volume included between the two walls.

(24) FIG. 9 shows the two jaws separated releasing a cushion from the machine, which cushion is inflated according to the last use described above. Note that the heat-sealed zone 27 where the two walls are welded comprises on its periphery a taurus-shaped zone 28 having zones 25, 29 in FIG. 10 where the two walls are welded, the zones 25, respectively 29 (see FIG. 10) are not continuous, hence the inside of the taurus is at the same pressure as the inside 26 of the cushion. In other words, the two walls in the welding zone are able to separate only slightly, which causes only a very slight loss of pressure in the cushion.

(25) In another form of execution of the use of a machine according to the invention, cushions are used that consist of two walls (plastic films) defining a closed space trapping a small quantity of air preventing the two walls from sticking. The latter operation having been carried out previously before entering the machine according to the invention, for example on another machine, known to those skilled in the art. The use proceeds in the following manner:

(26) A) The two walls of a cushion having two walls that are not stuck together are positioned.

(27) B) The two jaws are moved so as to clamp between their terminal faces the two sheets of plastic forming the walls of the cushion.

(28) C) The aspiration device is activated in the channels placed in rings on the terminal faces of the two bodies forming the jaws. The two walls are then kept separated, stuck against said faces.

(29) D) A needle contained in the body of the machine having an opening at its point and moved so as to pierce only the first wall while leaving the other intact.

(30) E) The pressurized air is injected into the cushion inflating the latter.

(31) F) The jaws are brought together clamping the two walls between them while compressing the air contained in the cushion.

(32) G) In the same manner as in the use described above, the cylinder 17 contained in the body 11 of the jaw 2 is moved so as to press on the periphery of the orifice for the needle 5 to exit the body 3. The heating element is activated heat-sealing the two walls along a ring surrounding the hole of the needle preventing the air from leaving the cushion. And the use (method) ends like that previously described with respect to FIG. 9.

(33) In yet another form of execution of a machine according to the invention for inflating cushions, on which a hole has already been made in at least one of the walls, the use will proceed in the following manner:

(34) A) The two walls of a cushion are placed between the jaws so that the hole is placed opposite the outlet orifice of the needle in the face of one of the bodies.

(35) B) The suction device is actuated, the two jaws are separated each keeping one of the walls stuck against them.

(36) D) The pressurized gas is then injected into the cushion through the outlet orifice of the needle provided in the terminal face of one of the jaws without the needle being moved.

(37) The rest of the process then unfolds as described above.

(38) It is also possible to design variants of use in which the cushion is pierced in any location, for example in a corner, or in which the cushion has a protuberance 36 (see FIG. 11) relative to its general shape, the inside 34 of said protuberance being connected to its general volume 36 of said cushion by a duct 33 that will be closed by heat-sealing 37. As can be seen in FIG. 11, a protuberance 36 is attached to the general volume 32 of a cushion by a duct 33, the two films forming the cushion being welded along the line 35.

(39) As can be seen, all the operations described above require no human intervention. Moreover, it is possible to inflate cushions to a higher pressure than by the methods known hitherto. Finally, the piercing can be carried out at any location on the cushion, for example in a corner, in the middle, at an edge, and it is possible to inflate any shape of cushion, even having several pockets communicating with one another. The cushions obtained by a method according to the invention are more inflated, hence more rigid and can, in certain cases, replace the polystyrene shells. The inflation pressure may vary depending on the strength and the thickness of the sheets forming the walls.