Abstract:
An applicator device comprising a casing, a storage compartment for a product to be applied, an application element comprising a ball held rotatably in a ball holder, a sealing element which is displaceable along a predetermined path between a first position with respect to the casing in which it bears sealingly against the ball and a second position with respect to the casing in which it releases the ball for application of the product, and an increased pressure-producing device for producing an increased pressure in the storage compartment, wherein the sealing element is coupled in a predetermined portion of the path to the increased pressure-producing device. The sealing element is independent of the increased pressure-producing device in a first portion of the path which is delimited by the first position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to an applicator device comprising a casing, a storage means for a product to be applied, an application means comprising a ball held rotatably in a ball holder, a sealing means which is displaceable along a predetermined path between a first position with respect to the casing in which it bears sealingly against the ball and a second position with respect to the casing in which it releases the ball for application of the product, and an increased pressure-producing means for producing an increased pressure in the storage means, wherein the sealing means is coupled in a predetermined portion of the path to the increased pressure-producing means.  
         [0002]     Applicator devices are known, for example from EP 1 445 121 A1.  
         [0003]     As the sealing means in the above-mentioned first position bears sealingly against the ball, it urges the ball into the ball holder in such a way that a gap is produced between the ball holder and the ball, through which gap the product to be applied can issue as soon as an increased pressure obtains in the storage means. As, in the known applicator devices, the predetermined portion of the path of the sealing means from the first position into the second position, that is to say that portion of the path in which the sealing means is coupled to the increased pressure-producing means, directly adjoins the first position, an increased pressure is produced in the storage means while the ball is still being urged into the ball holder by the sealing means, for which reason there is the risk of the product escaping.  
         [0004]     The object of the present invention is to provide an applicator device wherein the risk of the product which is to be applied from running out of the applicator is reduced.  
       SUMMARY OF THE INVENTION  
       [0005]     According to the invention the object is attained wherein sealing means is independent of the increased pressure-producing means in a first portion of the path which is delimited by the first position.  
         [0006]     In other words that portion of the path of the sealing means from the first position into the second position, in which the sealing means is coupled to the increased pressure-producing means, does not directly adjoin the first position. Rather, coupling of the sealing means to the increased pressure-producing means takes place only in a later portion of that path of movement, and for that reason no increased pressure is produced in the storage means as long as the ball is still urged into the ball holder by the sealing means in such a way that a gap opens between the ball and the ball holder. Rather, the increase in the pressure in the storage means takes place only when the sealing means has left the ball and the above-indicated gap is closed. That reduces the risk of the product which is to be applied running out.  
         [0007]     In accordance with a preferred embodiment of the invention there is provided a screwthread for displacing the sealing means with respect to the casing. That configuration is mechanically particularly simple to embody.  
         [0008]     Additionally or alternatively it is also possible to provide a bayonet connection.  
         [0009]     In a further preferred feature there is provided a coupling means for coupling the sealing means to the increased pressure-producing means in the predetermined portion of the path of movement. Such a coupling means more specifically permits uncoupling in said first portion of that path.  
         [0010]     In that case the coupling means preferably has a first coupling element at the sealing means and a second coupling element at the increased pressure-producing means, which can be coupled together by way of a frictional engagement and/or by way of a positively locking engagement.  
         [0011]     In that case the two coupling elements can be provided integrally at the sealing means and at the increased pressure-producing means respectively or can be in the form of a separate portion and connected to said components.  
         [0012]     The coupling means can have a ring of teeth at the increased pressure-producing means and/or at the sealing means.  
         [0013]     In other words that configuration operates essentially with a positively locking connection.  
         [0014]     Both such a positively locking connection and also a frictional connection can be designed in such a way that overall the arrangement affords a slipping clutch, for example in order to limit the increased pressure produced in the storage means.  
         [0015]     Particularly in the case of the ring of teeth, it can be provided in accordance with the invention that the coupling means has at least one tooth-like projection on the sealing means and/or the increased pressure-producing means.  
         [0016]     The ring of teeth and/or the tooth-like projection is/are preferably provided on a sleeve-like projection which preferably has at least one longitudinal slot.  
         [0017]     That design configuration is preferred in comparison with a design configuration for example with three rings of teeth because coupling engagement takes place more easily.  
         [0018]     In accordance with a particularly preferred feature of the invention it is provided that the increased pressure-producing means is controllable in such a fashion as to afford a reduction in the pressure in the storage means.  
         [0019]     That is advantageous in particular in regard to non-leak security.  
         [0020]     In accordance with a further preferred embodiment of the invention it is provided that the increased pressure-producing means has a transmission means with at least one female screwthread element and at least one male screwthread element, wherein the transmission means can assume at least two operating conditions, namely a first operating condition in which the two screwthread elements mesh with each other to produce the increased pressure, and a second operating condition in which they do not mesh with each other, thereby resulting in a reduction in the increased pressure.  
         [0021]     In other words, in accordance with this preferred embodiment of the invention it is provided that two screwthread elements are coupled together to produce the increased pressure and are uncoupled to reduce the pressure in the storage means. That affords a solution which is particularly simple from the point of view of structure, inexpensive and easy to handle.  
         [0022]     It can happen that a user of the applicator device forgets to reduce the pressure in the storage means after work has been done. In such a case, under some circumstances, the product which is to be applied can suffer damage in the storage means. In addition it is not possible to be sure that the product will not run out.  
         [0023]     In accordance with a particularly preferred embodiment of the invention it is therefore provided that the applicator device can assume at least two operating conditions, namely a rest condition and a use condition, and has a means for reducing the pressure in the storage means, said pressure-reducing means being responsive to a movement of the applicator device from the use condition into the rest condition.  
         [0024]     In other words, this configuration of the invention provides that the pressure in the storage means is automatically reduced as soon as the applicator device is moved into the rest condition, after its work has been done.  
         [0025]     In that respect it can be provided that the applicator device is put into the rest condition by putting the sealing means into the first position with respect to the casing.  
         [0026]     In other words, this configuration of the invention provides that putting the sealing means into the first position, that is to say into that position in which it bears sealingly against the ball, results in an automatic reduction in the pressure in the storage means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]     The invention is described in greater detail hereinafter by means of a preferred embodiment in the form of pencils with reference to the accompanying drawing in which:  
         [0028]      FIG. 1  is a view in longitudinal section of a pencil according to a particularly preferred embodiment of the invention,  
         [0029]      FIG. 2  shows views of a plunger arrangement of the pencil of  FIG. 1 ,  
         [0030]      FIG. 3  shows views of a control pushrod of the pencil of  FIG. 1 ,  
         [0031]      FIGS. 4 through 7  show diagrammatic views in section relating to the co-operation of a cap with the pencil, and  
         [0032]      FIGS. 8 and 9  show diagrammatic views in section of the front portion of the pencil with the cap. 
     
    
     DETAILED DESCRIPTION  
       [0033]     Referring to  FIG. 1 , the pencil has an external shaft  10  which serves as a casing and on to which a cap  12  is screwed in the operating position shown in  FIG. 1  (rest position). For that purpose there is a screwthread identified by reference numeral  14 . The cap  12  has a seal  16  which sealingly embraces a tip  18  in the operating condition shown in  FIG. 1 . At the free end of the tip a ball  20  is held in a ball holder  21  against which the seal  16  sealingly bears.  
         [0034]     The tip  18  is enclosed by a cartridge sleeve  22  at its end portion remote from the ball  20 . The cap  12  is rotationally coupled to the sleeve  22  in portion-wise manner in a fashion described in greater detail hereinafter.  
         [0035]     The internal space of the sleeve  22  forms a storage means  24  for ink  26 . Arranged on the side remote from the ball  20  in the storage means  24  is a closure mass  28  which serves for sealing off in relation to the ambient atmosphere. The rear boundary of the storage means  24  is formed by a plunger  30 . The plunger  30  is disposed slidably within the storage means  24 . As seen from the ball, a plunger holder  32  is disposed behind the plunger  30 . A control pushrod  34  projects into the plunger holder. A spring  36  bears on the one hand against the control pushrod  34  and on the other hand against a closure cap  38 .  
         [0036]     As can be seen from  FIG. 2  the plunger  30  has a projection  40  which in the assembled condition engages into a window  42  in the plunger holder  32 . At its end portion remote from the plunger  30  the plunger holder  32  has projections  44  and  46  which engage into corresponding recesses in the cartridge shaft  22 , for rotational coupling purposes. Accordingly the plunger holder  32  is admittedly rotationally coupled to the cartridge shaft  32  but it is held axially slidably therein.  
         [0037]     Also at its end portion remote from the plunger  30  the plunger holder  32  is provided in its interior with a substantially hemispherical female screwthread element  48  which serves for coupling—at times—to the control pushrod  34 .  
         [0038]     The control pushrod  34  is provided with male screwthread elements which are complementary to the female screwthread element  48  and of which one is identified by way of example by reference numeral  50 . The male screwthread elements  50  correspond to segments of a helicoidal groove and respectively extend over an angle of somewhat more than 300°. They are interrupted by a longitudinal groove  52  which extends over an angle of about 27°.  
         [0039]     At its end portion remote from the wall  20  the control pushrod  34  is provided with projections  54 ,  56 ,  58  and  60  which engage into corresponding recesses in the external shaft  10  for rotational coupling purposes. The control pushrod  34  is however axially slidable with respect to the external shaft  10  between the closure cap  38  and an abutment  62 . The function of the pencil illustrated in the drawing is as follows:  
         [0040]      FIGS. 4 through 7  show various operating positions of the cap  12  with respect to the external shaft  10  serving as a casing.  
         [0041]     As can be seen in particular from  FIGS. 4 through 7 , provided in the internal space of the cap  12  is a sleeve-shaped projection  66  which projects beyond the seal  16  and has at least one longitudinal slot  68 . Provided on the inside of the projection  66  is a series of tooth-like projections of which one is identified by way of example by reference numeral  70 .  
         [0042]     The sleeve  22  carries a ring of teeth  72  which are matched to the tooth-like projections  70  on the projection  66 .  
         [0043]     As already mentioned above,  FIG. 1  shows the rest position of the pencil, that is to say that position in which the cap  12  is screwed on to the external shaft  10  serving as the casing, more specifically in such a way that the seal  16  bears sealingly against the ball  20 . The same position (rest position) is also shown in  FIG. 4 . When now the cap  12  is unscrewed from the external shaft  10 , the cap moves towards the left in  FIG. 4 . In a first portion  74  ( FIG. 4 ) of that path of movement the tooth-like projections  70  are not in engagement with the ring of teeth  72 , for which reason the sleeve  22  is not also rotated by the cap  12 . Rather, the tooth-like projections  70  only come into engagement with the ring of teeth  72  in a later portion  76  of the path of the cap  12  from the rest position into the operative position. In that position the seal  16  has already lifted off the ball  20 . That condition is shown in  FIG. 5 . Because of the engagement of the tooth-like projections  70  into the ring of teeth  72 , the sleeve  22  now rotates with the cap  12 .  
         [0044]     The portion  76  is adjoined by a portion  78  in which the tooth-like projections  70  have again left the ring of teeth  72 , see  FIGS. 6 and 7 . In that operative position further rotation of the cap  12  with respect to the external shaft  10  does not cause any further rotational movement of the sleeve  22 .  
         [0045]     In the operating position shown in  FIG. 1  (rest position), that is to say when the cap  12  is screwed on to the external shaft  10 , the female screwthread element  48  is in the groove  52 . Accordingly in that operating position there is no coupling between the control pushrod  34  and the plunger  30 . The plunger  30  accordingly does not apply any pressure to the closure mass  28  or the ink  26 .  
         [0046]     When the cap  12  is rotated with respect to the external shaft  10  in order to unscrew it, then, because of the rotational coupling effect which is not yet present between the cap  12  and the sleeve  22 , in the first portion  74  of the path of movement of the cap  12 , the plunger holder  32  does not rotate. Rotary movement of the plunger holder  32  first takes place in the portion  76  of the path of movement of the cap  12 , more specifically by virtue of the engagement of the tooth-like projections  70  into the ring of teeth  72 . In the further course of the-rotary movement the female screwthread element  48  leaves the groove  52  and passes into the male screwthread element  50 . Further rotary movement in that condition means that the female screwthread element  48  travels along the male screwthread element  50 , whereby the control pushrod  34  which hitherto has been supported against the projection  62  is displaced against the spring  36 . As a result the elastic return force of the spring  36  acts by way of the control pushrod  34  on the plunger holder  32  and thus on the plunger  30 , whereby the pressure in the storage means  24  rises. At its end the male screwthread element  50  is limited by an abutment  64  against which the female screwthread element  48  butts upon further rotary movement. In the embodiment illustrated in the drawing the dimensions are so selected that, with the female screwthread element  48  butting against the abutment  64 , the cap  12  reaches the portion  78  in which the tooth-like projections  70  are no longer in engagement with the ring of teeth  12 .  
         [0047]     It is however not out of the question that production tolerances cause difficulty in accurate matching. The longitudinal slot  68  is accordingly provided. More specifically, if the female screwthread element  48  should butt against the abutment  64  while the tooth-like projections  70  are still in engagement with the ring of teeth  72 , then the projection  66  can expand because of the longitudinal slot  68  so that the tooth-like projections  70  slip on the ring of teeth (slipping clutch) and therefore the tooth-like projections  70  and the ring of teeth  72  are not damaged.  
         [0048]     The increased pressure which is now built up in the storage means  24  can be used for discharging the ink  26 . The pencil is now in the operative position.  
         [0049]     When, after use of the pencil, the cap  12  is screwed on to the external shaft  10  again, then the female screwthread element  48  travels along the male screwthread element  50  back into the groove  52  again, because of the coupling effects described in detail hereinbefore, in the portion  76 . As a result, under the influence of the spring  36 , the control pushrod  34  travels again towards the abutment  62  where it is supported. Accordingly the spring  36  no longer acts on the ink  26  by way of the plunger holder  32  and the plunger  30 . In that condition there is no longer any increased pressure obtaining in the storage means  24 , which is of great advantage in terms of protecting the ink  26  and the closure mass  28  by being gentle therewith and in regard to the anti-leakage safeguard.  
         [0050]     When the cap  12  is screwed on to the external shaft  10  the plunger holder  32  is moved away from the ball  20  until the female screwthread element  48  passes into the groove  52 . So that in that case the plunger  30  does not suck the ink out of the tip  18  the plunger  32  is in the form of a trailing plunger. More specifically the plunger holder  32  can move away from the ball  20  in accordance with the axial length of the window  42  without entrainment of the plunger  30 .  
         [0051]     In addition to or instead of the projection  40  in the window  42  it is also possible to provide an elastic coupling means between the plunger holder  42  and the plunger.  
         [0052]     The elastic coupling means and/or the play can however also be connected elsewhere between the control pushrod  34  and the plunger surface which delimits the storage means  24 .  
         [0053]     The rotary transmission means shown in  FIGS. 1 through 3  can compensate for a reduction in the filling level in the storage means  24 . More specifically, with a reducing filling level the plunger holder  32  moves together with the plunger  30  gradually into the storage means  24  whereas the control pushrod  34  does not change its position relative to the spring  36  in accordance with the filling level, for which reason the same return force is always available for producing the increased pressure.  
         [0054]     The closure cap  38  can be held resiliently in the manner of a shock absorber. The spring  36  serves for that resilient holding effect, that is to say that elastic element whose return force serves to produce the increased pressure in the storage means  24 . That configuration thereby provides for minimising the number of components involved.  
         [0055]     The features of the invention disclosed in the foregoing description, the claims and the drawing can be essential both individually and also in any combinations for implementing the invention in the various embodiments thereof.