Patent Publication Number: US-2003230599-A1

Title: Spring and dispenser comprising such a spring

Description:
CROSS REFERENCE TO RELATED APPLICATION  
     [0001] This application claims the benefit under 35 U.S.C. §119(e) of pending U.S. provisional patent application Serial No. 60/342,369, filed Dec. 27, 2001, and priority under 35 U.S.C. §119(a)-(d) of French patent application No. FR-01.14725, filed Nov. 14, 2001. 
    
    
     
       TECHNICAL FIELD  
       [0002] The present invention relates to a spring and a dispensing device using such a spring as a return spring used to return the dispenser to the idle position. However, the spring must not be restricted only to use in such a dispenser. Indeed, it may also be used in any other system requiring elastic return means.  
       BACKGROUND OF THE INVENTION  
       [0003] Numerous types of springs already exist and the most commonly used is the conventional cylindrical, and more rarely conical, shaped spiral spring. When such a spiral spring is to be mounted in an automated manner in a specific device or system, this requires the orientation and seizure of the spring using a suitable machine such as a robot. This is due to the fact that it is difficult for a spiral spring to remain upright due to its cylindrical and elongated configuration. Therefore, it cannot be fed directly into a device at a suitable point from bulk storage.  
       [0004] The present invention defines another type of spring, wherein the orientation is advantageously easier, in that the spring is positioned almost automatically in a position wherein it can perform its function as a spring.  
       [0005] The document U.S. Pat. No. 2,432,288 already discloses a spring composed of two curved blades against each other, the end of one blade coming into contact with the other blade. When pressing on this spring to bring the blades closer together, it is impossible to bring the two blades back into contact with each other. Therefore, this spring must never by flat, i.e. be very thin.  
       [0006] The document U.S. Pat. No. 4,932,508 also discloses a zigzag-shaped blade spring. Each blade of the spring is formed with a window in which a curved tab is cut, which may come into contact with the other blade when the spring is compressed. The free end of the tab slides on the blade when the spring is compressed.  
       [0007] In these springs according to the prior art, it is not possible to produce them in an extremely flat configuration, since the means producing the stiffness of the spring, in this case, the end of a blade or the tab, do not permit it.  
       SUMMARY OF THE INVENTION  
       [0008] The aim of the present invention is to remedy this drawback of the prior art by defining a spring which can easily adopt an extremely flat configuration, while offering satisfactory stiffness under compression.  
       [0009] For this purpose, the present invention relates to a spring comprising two branches connected by a bend such that the branches form, in the idle position, an acute angle, said branches being elastically mobile in relation to each other by relative pivoting around the bend until they come into contact with each other so as to be extended relatively in parallel, characterised in that it comprises spring stiffness variation means which produce different stiffnesses depending on whether the spring is compressed or slackened, said variation means producing a low stiffness when the branches are extended relatively in parallel and a greater stiffness when the branches are forced together from the idle position. The branches of the spring are relatively identical and advantageously straight and relatively plane. In addition, the width of the branches is greater than half of their length. For this reason, the spring is positioned almost automatically on one of these two branches such that it can fulfil its function as spring by pressing on the other branch which is not resting on the bearing surface. Advantageously, the bend extends over the entire branch width.  
       [0010] Therefore, the spring comprises a particularly simple configuration in the form of a slightly open hairpin that can easily be manufactured from a cut and bent metal blade or by moulding plastics.  
       [0011] The stiffness variation means only become fully operative after an initial release of the branches when they are initially brought closer together again. It is the variation means that act on the spring stiffness and not the bend. The variation means act in a way similar to a spring arming function which gives the spring its full stiffness.  
       [0012] When the variation means are fully operative, the role of the bend is limited to a joint between the two branches, but only represents a low contribution to the total spring stiffness. The elastic deformation of the spring then takes place on the branches and/or variation means.  
       [0013] Advantageously, the spring stiffness variation means comprise locking means preventing the branches from being returned to a relatively parallel position from the idle position.  
       [0014] According to one embodiment of the invention, the variation means comprise at least one tab attached to a so-called first branch and extending between the two branches to the other so-called second branch, said tab comprising one free end and one end connected to the first branch, said second branch comprising a stop housing intended to receive the free end of the tab, said free end being locked at a stop in the housing when the two branches are forced against each other, thus preventing the branches from being brought against each other by pivoting around the bend. If the free end of the tab is prevented from being inserted in the housing of the second branch when the branches are brought closer together, it is then possible to flatten the spring completely with the elastically deformed tab so as to extend relatively parallel to and between the branches. In this flattened configuration, the tab contributes to the total stiffness of the spring in conjunction with the bend. It is the elastic deformation of the tab on its connection with the branch that generates the stiffness. On the other hand, if the tab is left free from any outside strain, then its free end is automatically inserted in the housing of the second branch and remains locked even if the spring is at maximum compression. The stiffness of the spring is in this case much greater than that of the spring when it is flattened with the tab which extends between the parallel branches.  
       [0015] According to a practical embodiment, the tab extends with its free end oriented relatively towards the bend, the free end of the tab being located between the stop housing and the bend when the branches are relatively parallel. In an alternative embodiment, the tab extends with its free end oriented relatively towards the free ends of the branches, the free end of the tab being located between the stop housing and the free ends of the tabs when the branches are relatively parallel. Advantageously, the first branch forms a window wherein the tab is housed by elastic deformation when the two branches are extended relatively in parallel.  
       [0016] The invention also relates to a fluid product dispenser comprising:  
       [0017] a reservoir containing said fluid product and equipped with at least one actuating wall on which pressure is exerted to reduce the volume of the reservoir,  
       [0018] a dispensing outlet through which the fluid product is dispensed,  
       [0019] characterised in that the reservoir contains a spring as defined above. Advantageously, a removable sealing component seals the dispensing outlet and thus isolates the reservoir from the outside, the spring being compressed so as to occupy a minimum volume when the sealing component seals the dispensing outlet. In this way, the spring is slackened to increase the volume of the reservoir when the sealing component is removed by introducing gas into the reservoir via the dispensing outlet. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0020] The use of such a spring is particularly advantageous in such a fluid product dispenser, since it is simply necessary to deposit the spring in the reservoir when the dispenser is being manufactured, without having to worry about its specific orientation, given that the spring is automatically positioned on one of the two branches. This does away with the need for a prior spring orientation and seizure operation. In addition, such a spring may be manufactured at a low cost.  
     [0021] The invention will now be described in more detail with reference to the figures attached, showing a non-restrictive example of an embodiment of the spring according to the invention, and implementation in a specific fluid product dispenser.  
     [0022] In the figures:  
     [0023]FIG. 1 is a perspective view of the spring in FIG. 1,  
     [0024]FIG. 2 is a vertical transverse section view of the spring in FIG. 1 in the compressed state,  
     [0025]FIG. 3 is a view of the spring in FIGS. 1 and 3 during compression with fully operative variation means,  
     [0026]FIG. 4 is a vertical transverse section view of a fluid product dispenser using a spring in FIGS.  1  to  3 , said dispenser not being used, and  
     [0027]FIG. 5 is a section view of the dispenser in FIG. 4 ready for use. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0028] The spring shown in the figures and used to illustrate the present invention is presented in the general form of an open pin. The spring referred to in general with the numerical reference  4  comprises two branches  41  and  42  connected together at one of their ends by a bend  40 . The two branches  41  and  42  are extended in relation to each other, producing an acute angle, for example located between 20 and 60°. It is easy to understand that such a pin may easily be deformed elastically by bringing the branches closer together, which is performed by a deformation/pivoting movement around the bend  40 . By choosing a suitable material such as metal or plastic, with good shape retention, the two branches return elastically to their original position once the pressure force ceases to be exerted on said branches.  
     [0029] Preferentially, the branches of the spring are relatively wide in relation to their length: the width of the branches may for example be greater than half the length of the branches. In addition, the two branches are advantageously relatively straight and plane, such that they offer an extensive and particularly stable bearing surface. Preferentially, the two branches are relatively identical such that it is completely irrelevant whether the spring rests on either of the branches. With such a configuration, the spring is automatically positioned on one of these two branches. It is indeed practically impossible for the spring to be positioned on the edge of the branches: this is rendered even more improbable by the fact that the free end of the branches is rounded.  
     [0030] According to the invention, the spring comprises spring stiffness variation means capable of preventing the branches from being brought relatively in parallel. The variation means are inoperative or produce a low stiffness when the branches extend relatively in parallel and, on the other hand, become fully operative or produce a higher stiffness when the branches are forced against each other from the idle position. These variation means are presented in this case in the form of a tab  43  which extends from the branch  41  to the other branch  42 . In other words, the tab  43  extends between the two branches in the acute angle. The tab  43  comprises one connected end of the branch  41  and one free end  431  which points towards the other branch  42 . The tab  43  also extends in an inclined manner such that the free end  431  is oriented towards the bend  40 . However, it is possible to envisage an alternative embodiment for the tab  43  such that its free end  431  is oriented towards the free ends of the branches  41  and  42 . The tab  43 , like the branches  41  and  42  preferentially comprise elastic deformability, although it can be said that they are relatively stiff. The term resilience may be used.  
     [0031] According to the invention, the branch  42  forms a stop housing  44  adapted to receive the free end  431  from the tab  43 . This is visible in FIG. 3. In the idle position shown in FIG. 1, the free end  431  of the tab  43  is not necessarily received in the stop housing  44  of the other branch  42 . The idle position may also be the moulding position or shape. However, as can be seen in FIG. 1, the free end  431  of the tab  43  is positioned in the vicinity of the stop housing  44  and, in any case, in the vicinity or in contact with the branch  42 . By pressing on the branches so as to bring them closer together, the free end  431  of the tab moves in relation to the branch  42  in the direction of the stop housing  44 . By continuing to press on the branches, the free end  431  will be housed in the stop housing  44 : however, the stop housing  44  shows a configuration capable of keeping the free end  431  locked even if pressure is continued to be applied onto the branches so as to bring them closer together. Given that the branches and/or the tab  43  are elastically deformable, it is possible to bring the free ends of the branches  41  and  42  closer together by means of elastic deformation of the branches and/or the tab  43 , as shown by the dotted lines in FIG. 3. The tab  43  prevents the branches  41  and  42  from coming closer together by pivoting around the bend  40 . Indeed, the angle produced by the branches at the bend  40  remains unchanged when the branches are pressed to bring them closer together. The stiffness of the spring is essentially produced directly by the tab which acts as a lock or prop between the branches.  
     [0032] However, it is possible to bring the branches back into contact with each other so as to extend relatively in parallel by preventing the free end  431  from being inserted into the stop housing  44  of the branch  42 . This is shown in FIG. 2. For this, it is simply necessary to force the tab  43  slightly so that it passes over the stop housing  44  without being inserted into it. The free end  431  may then be positioned beyond the stop housing  44 , i.e. between said housing and the bend  40 . This would not apply if the tab  43  extends in the other direction, i.e. towards the free ends of the branches. It is clearly seen in FIG. 2 that the tab  43  is relatively parallel to the branches  41  and  42  which are also relatively or perfectly parallel. In order to enable the tab  43  to be housed between the branches, it must comprise a certain elasticity at its junction with the branch  41  and, in addition, the branch  41  forms a window  430  inside which the tab  43  may be housed. The spring in FIG. 2 is extremely flat, its thickness corresponding approximately to the thickness of the spring at the bend  40 . The tab  43 , i.e. the variation means, is practically inoperative in this position since the free end  431  is not inserted in the stop housing  44 . However, the tab  43 , due to the fact that it is elastically deformed, tends to exert a force on the branches by increasing the distance between them. Consequently, the tab  43 , even in the practically inoperative positive, contributes, in addition to the bend  40 , to the stiffness of the spring which tends to return the branches  41  and  42  to the idle position as shown in FIG. 1. However, the stiffness produced by the bend  40  and the practically inoperative tab is not considerable such that a minimal force is sufficient to keep the spring in the configuration in FIG. 2. By releasing the spring when it is in the configuration in FIG. 2, the branches  41  and  42  will pivot in relation to each other around the bend  40  assisted by the release of the tab  43 . When the branches are separated, the free end  431  of the tab  43  will pass over the stop housing  44  and continue its path to the position shown in FIG. 1. The spring is then in the idle position. By pressing again on the branches so as to bring them closer together, the free end  431  will be inserted and remain locked in the stop housing  44 . The subsequent dynamic behaviour has already been described above. It is easy to understand that the stiffness of the spring when the tab  43  is inserted in the stop housing  44  is considerably greater than the stiffness of the spring in the configuration in FIG. 2, i.e. with the tab  43  disengaged from the stop housing  44 . The stiffness of the spring in the configuration in FIG. 2 may just be sufficient to enable the tab  43  to be inserted into the housing  44 . However, it is preferable to provide a margin such that the tab  43  is positioned in front of the housing as shown in FIG. 1. With no external intervention to force the tab  43 , it will never be able to return to its position as shown in FIG. 2. Indeed, the stop housing  44  acts as an impassable barrier or stop for the free end  431 . It is only by forcing the tab  43  that it is possible to restore the configuration in FIG. 2.  
     [0033] Using the spring stiffness variation means, the spring comprises two different stiffness values, i.e. a low value when the branches are separated from a maximum compressed state (FIG. 2), and a higher value when the branches are brought closer together from the idle position in FIG. 1. This difference in stiffness values is a particularly advantageous characteristic in certain applications as seen below.  
     [0034] Such a spring may for example be produced from a cut and bent metal blade. The spring may preferentially be produced from moulded plastic.  
     [0035] The spring as described above has a special application in a fluid product dispenser as shown in FIGS. 4 and 5.  
     [0036] In this non-restrictive example of an embodiment, the dispenser may be produced from two sheets of flexible complex film  1  and  2  which are welded together on their edge  11 ,  12  so as to define a volume between them which is approximately equivalent to that of a fluid product reservoir  3 . An insert  5  may also be placed between the two sheets  1  and  2 : this insert  5  defines a dispensing outlet  50  and a housing wherein a porous fibre  6  may be housed so as to extend inside the reservoir  3 . This fibre  6  is intended to be impregnated with fluid product contained inside the reservoir  3 . Once this fibre is soaked in product, it is simply necessary to pass an air stream through the fibre, which creates a two-phase distribution at the dispensing outlet  50  of the insert  5 . At the front of the dispensing outlet  50 , the two sheets  1  and  2  welded together define a tear-off or fold-away strip  12  which seals the dispensing outlet  50  so as to isolate the reservoir  3  from the outside.  
     [0037] According to the invention, the reservoir  3  contains a spring  4  which is placed between the two sheets  1  and  2 . The spring  4 , as shown in FIG. 2, acts at least on one wall of the dispenser, which may be the actuation wall, so as to increase the internal volume of the reservoir  3 . According to a particularly beneficial characteristic, the spring  4  is fully compressed as shown in FIG. 2, while the sealing component  12  seals the dispensing outlet  50  and thus isolates the reservoir  3  from the outside. In other words, the reservoir  3  was sealed during its manufacture with the fully compressed spring such that the reservoir is at minimum volume. In this case shown in FIG. 1, the reservoir  1  contains practically only fluid product and practically no gas or none at all. Given that the reservoir  3  is perfectly isolated from the outside by the sealing component  12 , the spring  4  cannot be slackened inside the reservoir  3  due to the atmospheric pressure exerted on the walls  1  and  2  of the reservoir. The dispenser can then be stored before use in this state, it is particularly thin with a thickness defined approximately by the thickness of the spring  4  in its completely compressed state added to the cumulative thickness of the two sheets of film  1  and  2 . The spring  4  then defines a minimum volume wherein the fluid product is stored without being subjected to practically any pressure. In this way, there is no risk of leaks due to crushing of the reservoir  3 . Such a dispenser may for example be inserted in a magazine since it is particularly flat and particularly resistant to pressure.  
     [0038] As soon as the sealing component  12  is removed, air can enter inside the reservoir  3  via the dispensing outlet  50  such that the spring  4  can slacken inside the reservoir so as to increase its internal volume. This is possible by means of the stiffness of the spring produced by the bend and the elastically compressed tab, located, however, outside the stop housing. It is sufficient for this stiffness to enable the branches to separate in spite of the resistance of the sheets composing the reservoir. The reservoir  3  is then filled with fluid product and gas, generally air. To obtain dispensing of sprayed product, it is simply necessary to press on the wall  1  with your thumb for example against the action of the spring  4  so as to discharge the air via the fibre  6  impregnated with fluid product. The air passing through the impregnated fibre  6  creates two-phase spraying at the dispensing outlet  50 . As soon as the pressure is released on the actuation wall  1 , it returns to its shape shown in FIG. 2, due to the elastic action of the spring  4 .  
     [0039] The spring  4  acts as a spacer in the storage state (FIG. 4) by determining a minimum volume for the reservoir  3 , as a primer when the sealing component  12  is torn off by increasing the volume of the reservoir  3  and as a return spring when actuated by pressing on the actuation wall  1 .  
     [0040] The use of a spring as defined above with reference to FIGS.  1  to  3  is particularly advantageous in this type of dispenser, given that it may be placed in the reservoir when the dispenser is manufactured, with no specific orientation, due to the fact that the spring is positioned automatically on one of these two branches. In addition, it is extremely flat when totally compressed, which makes it possible to produce particularly flat dispensers, which is advantageous for the above-mentioned reasons. It is also important to note that, when completely compressed, the spring does not press very strongly on the sheets forming the reservoir. Indeed, due to the low value of the spring stiffness in this position corresponding to that in FIG. 2, the branches are not pushed strongly apart, and, for this reason, the branches do not press as strongly against the sheets. The advantage is that the sheets are not marked or very slightly marked by the branches due to their low pressure. On the other hand, as soon as the spring is able to slacken due to the penetration of air into the reservoir, the tab  43  may be inserted in the stop housing  44  and the stiffness is then increased considerably. This gives a dispenser with a very effective return spring, while in the completely compressed position in FIG. 2, this spring only showed a considerably weaker force.  
     [0041] In FIG. 5, it is possible to see, in dotted lines, the deformation of the spring  4  when the dispenser reservoir is pressed. It is preferable for the tab and the branch forming the stop housing to deform elastically to increase the clearance of the spring.  
     [0042] Using this specific spring with variable stiffness, it is possible to produce a dispenser from simple fluid product packaging with no shape retention.