Patent Publication Number: US-2022226849-A1

Title: Device for applying a viscous substance

Description:
The invention relates to a device for applying a viscous substance, in particular for cosmetic, writing, painting, drawing and/or marking purposes, having a tank for the substance, an applicator and a conveyor designed to convey the substance from the tank to the applicator. 
     Devices of the type mentioned above are known, for example, from DE 103 27 589 B4. A container with a pump is also known from DE 197 42 559 C2. With the known devices, the conveyor consists of a plurality of individual parts, which requires a high degree of installation work. In addition, the known devices use materials that are critical in connection with cosmetic substances, for example. Examples are return springs made of steel and valve bodies made of steel. 
     The invention is based on the object of developing the device of the type mentioned above in such a way that the number of parts is reduced. Furthermore, with regard to the substances to be applied, critical materials are to be avoided. 
     According to the invention, the object is solved by the conveyor having a cylinder, a first and a second closing device, both of which are arranged in an axially displaceable manner in the cylinder, a pump tappet for axially displacing the closing devices, a first connecting channel between the cylinder and the tank and a second connecting channel between the cylinder and the applicator, the first closing device opening or closing the first connecting channel depending on its position relative to the cylinder and the second closing device being adjustable relative to the pump tappet, opening or closing the second connecting channel depending on its position relative to the pump tappet and, together with the cylinder, forming a pump in which it serves as a piston or represents the piston. 
     According to the invention, it is provided, in accordance with the above statements, that the pump tappet has a dual function, namely on the one hand the axial displacement of the two closing devices and on the other hand the opening or closing of the second connecting channel by changing its position relative to the second closing device. Firstly, this reduces the number of components required. By way of example, no (additional) valve has to be provided. Since, for example, a sphere as a valve body, which is usually made of steel, is thus also saved, critical substances are also avoided in connection with the substances to be applied. The second closing device also has a double function: closing and forming part of a pump. 
     The mode of operation of the application device designed according to the invention is, for example, such that by suitable movement of the two closing devices under control by means of the pump tappet, the substance to be applied is conveyed from the tank into the cylinder and from there to the applicator. 
     An application device comparable to the present invention is known from the German patent application 10 2018 003 323, which was filed on 24 Apr. 2018. In comparison, the applicator according to the present invention achieves a finer response behaviour due to shorter idle strokes in the respective stroke movements. Furthermore, there are fewer frictional influences due to the omission of one of the two connection openings in the outer surface of the pump tappet. A possibly provided pump cage can be integrated into the tank, whereby simpler and cheaper injection moulding tools can be used. Finally, safe leakage protection is achieved. It is even possible to work with stable ink. 
     According to the invention, it is preferably provided that the second closing device rests against a first stop of the pump tappet in the pressure stroke with respect to the cylinder and against a second stop of the pump tappet in the suction stroke with respect to the cylinder. 
     In other words, two stops are provided, by means of which the movement of the second closing device can be controlled by means of the pump tappet. 
     According to the invention, it is further preferably provided that the second closing device is adjustable between a first and second stop on the pump tappet and opens the second connecting channel when it abuts the first stop and closes the second connecting channel when it abuts the second stop. The two stops are preferably identical to the two stops against which the second closing device abuts in the pressure stroke or in the suction stroke. In this way, it can be achieved that the second connecting channel is automatically opened by the second closing device with respect to the cylinder in the pressure stroke and automatically closed in the suction stroke. In this way, a suction stroke followed by a pressure stroke can be used to convey substance from the cylinder to the applicator. 
     According to a further preferred embodiment of the invention, it is provided that the first closing device closes the first connecting channel in the pressure stroke relative to the cylinder and opens the first connecting channel at least in a partial section of the suction stroke relative to the cylinder. 
     In turn, this automatic closing or opening of the first connection channel ensures that substance is conveyed from the tank into the cylinder by means of a suction stroke. 
     According to the invention, successive pressure and suction strokes thus preferably cause the substance to be applied to be conveyed first from the tank into the cylinder and then further from the cylinder to the application element, wherein the opening and closing of the first and second connecting channel required for this purpose in each case takes place automatically, and in each case only by appropriate use of the two closing devices. 
     According to the invention, it is further preferably provided that the second connecting channel lies at least in sections in the pump tappet. This makes the conveyor and thus the entire application device particularly compact. 
     Further preferably, the second closing device surrounds the pump tappet in a ring-like or sleeve-like manner. It can thus be designed as an O-ring according to a particularly preferable embodiment of the invention. These designs serve in turn to achieve greater compactness. 
     According to the invention, the cylinder can preferably be formed in one piece with the tank. In this way, the number of parts is reduced. 
     Further preferably, it can be provided that the first closing device is designed in one piece with the pump tappet. This again serves to reduce the number of parts. However, the first closing device cannot be designed in one piece with the pump tappet as well. Their separate production causes hardly any problems and increases cost only insubstantially. 
     The movement of the pump tappet to control the two closing devices can, in accordance with the invention, be carried out in any way. However, it is preferably provided that the applicator has two parts which can be rotated against each other and a transmission that converts a rotation of the two parts against each other into an axial movement of the pump tappet. The two parts that can be rotated against each other can, for example, be two parts of the device shaft. In this design, it is sufficient to rotate the named parts in relation to each other in order to generate a pressure stroke or a suction stroke. 
     According to the invention, the transmission also preferably has a cam guided by means of a guide curve, wherein the guide curve runs along a closed path. With this design, for example, a suction stroke is also generated after a pressure stroke when the two parts that can be rotated against each other are always rotated in the same direction against each other. This is because, due to the closed path described by the guide curve, the cam over the pump tappet will always move the two closing devices back and forth, regardless of the direction in which the two rotatable parts are rotated against each other. 
     All parts can be made of plastic, in particular of ABS or PP. 
    
    
     
       In the following, the invention is explained in more detail by means of preferred exemplary embodiments with reference to the appended drawing. Here are shown: 
         FIG. 1  a longitudinal sectional view of a first exemplary embodiment of the applicator according to the invention, 
         FIG. 2 a    on the one hand, the same view as  FIG. 1 , but on a smaller scale, and on the other hand an enlarged partial view thereof, 
         FIGS. 2 b  to 2 e    the same views as  FIG. 2 a   , but in different operating conditions 
         FIG. 3  a cylinder, a tank and a drag piston of the applicator according to  FIG. 1 , 
         FIGS. 4 a  and 4 b    a pump tappet of the applicator according to  FIG. 1  in different rotational positions, 
         FIG. 5  a first rotatable part of the applicator according to  FIG. 1  in the form of a cartridge, 
         FIGS. 6 a  and 6 b    views of a drive ring of the applicator according to  FIG. 1 , 
         FIG. 7  a first closing device of the applicator according to  FIG. 1  in the form of a plug, 
         FIG. 8  a second closing device of the applicator according to  FIG. 1  in the form of an O-ring, 
         FIG. 9  the same view as  FIG. 1 , but from a different exemplary embodiment, 
         FIGS. 10 a  to 10 e    the same views as  FIGS. 2 a  to 2 e   , but from the second exemplary embodiment and 
         FIGS. 11 a  to 11 b    the same views as  FIGS. 4 a  and 4 b   , but again from the second exemplary embodiment. 
     
    
    
       FIG. 1  shows a sectional view of a first embodiment of the device  1  according to the invention for applying a viscous substance (hereinafter referred to as application device  1 ). The application device  1  extends along a longitudinal axis L which is parallel to a Z-axis direction. 
     The X-axis direction and the Y-axis direction are defined in such a way that  FIG. 1  is a sectional view in the Y-Z plane. The application device  1  has an applicator  2  for applying the viscous substance, for example for cosmetic, writing, painting, drawing and/or marking purposes. Furthermore, the application device  1  has a cartridge  50   a  connected to the applicator  2  and a shaft  50   b  connected to the cartridge  50   a . The cartridge  50   a  and the shaft  50   b  can be rotated against each other around the longitudinal axis L. For this reason, the cartridge  50   a  is also referred to as the first rotatable part and the shaft  50   b  as the second rotatable part. 
     The shaft  50   b  has a hollow interior designed as a tank  40  to receive the viscous substance, A pump cage  42  is formed in the tank  40 , said pump cage being connected to the tank  40  via a first connecting channel  41  ( FIG. 2 a   ), wherein the first connecting channel  41  is also referred to as the first dosing opening. Through the first connecting channel  41 , the viscous substance can pass from the tank  40  into the pump cage  42 . A drag piston  60  is arranged in the tank  40 , which moves towards the applicator  2  when the viscous substance is discharged from the tank  40 . In this way, a constant pressure is maintained in the tank  40 . Instead of the drag piston  60 , a closing mass can also be used. 
     A conveyor  3  serves to convey the viscous substance from the tank  40  via the pump cage  42  to the applicator  2 . For this purpose, the conveyor  3  has a cylinder  10 , which in the exemplary embodiment shown in  FIG. 1  is formed in one piece with the pump cage  42 . Furthermore, the conveyor  3  has an O-ring  30  arranged in an axially displaceable manner in the cylinder  10  and a pump tappet  20  for the axial displacement of the O-ring  30 . The O-ring  30  is pushed onto the pump tappet  20 . The pump tappet  20  has a front end  27   a  connected to the applicator  2  and a rear end  27   b  extending into the pump cage  42 . A tappet bore  26  extends from the front end  27   a  of the pump tappet  20  to its rear end  27   b  through the pump tappet  20 . At the rear end  27   b  of the pump tappet  20 , a second connecting channel  21  is formed, which represents a connection between the pump cage  42  and the tappet bore  26  and which is also referred to as the second dosing opening. 
     By rotating the cartridge  50   a  with respect to the shaft  50   b  around the longitudinal axis L, the pump tappet  20  is moved in the cylinder  10  along the longitudinal axis L (Z-axis). For this purpose, the application device  1  is designed with a transmission  23 ,  70 . The transmission  23 ,  70  has two cams  71  and a link  23 . The cams  71  are in engagement with the link  23  formed in the pump tappet  20 . As can be seen in  FIGS. 4 a  and 4 b   , the link  23  is designed as a sinusoidal channel. However, it is not restricted to this shape. If the two rotatable parts, i.e. the cartridge  50   a  and the shaft  50   b , are rotated against each other, the engagement of the cams  71  into the link  23  results in the rotational movement being converted into an axial movement of the pump tappet  20  along the longitudinal axis L. As can be further seen in  FIGS. 4 a  and 4 b   , the link  23  runs along a closed path. If the cartridge  50   a  and the shaft  50   b  are rotated against each other, the cams  71  will move the pump tappet  20  up and down again and again regardless of the direction of rotation due to the closed path of the link  23 . A first anti-rotation device  43  on the tank  40  and a second anti-rotation device  22  on the pump tappet  20  serve to rotationally couple the pump tappet  20  to the tank  40 . In the same way, a third anti-rotation device  72  on the drive ring  70  and a fourth anti-rotation device  52  on the cartridge  50   a  serve to rotationally couple the drive ring  70  to the cartridge  50   a.    
     If the pump tappet  20  is moved downwards from the position shown in  FIG. 1  by rotating the cartridge  50   a  and the shaft  50   b  against each other, a first stop  24   a  will abut the O-ring  30 . The O-ring  30  is therefore pressed downwards. If the pump tappet  20  is then moved upwards, a second stop  24   b  of the pump tappet  20  comes into contact with the O-ring  30 . The piston  30  is then moved upwards by the pump tappet  20 . Therefore, when the cartridge  50   a  and the shaft  50   b  are rotated against each other, the O-ring  30  is moved upwards and downwards again and again not only with respect to the cylinder  10 , but also with respect to the pump tappet  20 , regardless of the direction in which the cartridge  50   a  and the shaft  50   b  are rotated against each other. 
       FIGS. 4 a  and 4 b    show the pump tappet  20  of the conveyor  3  according to the invention having the sinusoidal link  23 , The pump tappet  20  shown in  FIG. 4 a    is rotated by 90° around the longitudinal axis L (Z axis) in  FIG. 4 b   . At the rear end  27   b  of the pump tappet  20 , the second connecting channel  21  can be seen in  FIG. 4 a   . Furthermore, the second anti-rotation device  22  can be seen in  FIG. 4 b   , which engages with the first anti-rotation device  43 . 
     In the following, the functionality of the application device  1  in the embodiment according to  FIG. 1  with reference to  FIGS. 2 a  to 2 e    is described by way of example: 
       FIG. 2 a   , like  FIG. 1 , shows the application device  1  in the starting position. In this position, the pump tappet  20  and the O-ring  30  are arranged in the cylinder  10  in such a way that the O-ring  30  closes the second connecting channel  21  of the pump tappet  20 . The tank  40  and the pump cage  42  are connected to each other via the first connecting channel  41 . The pump cage  42  is filled with the viscous substance in this starting position. 
     Now the cartridge  50   a  and the shaft  50   b  are rotated against each other around the longitudinal axis L. Thus, the rotation can occur in any direction. Due to the interaction of the link  23  and the cams  71 , the pump tappet  20  is displayed along the longitudinal axis L in the direction of the tank  40  as explained above. The rotation of the cartridge  50   a  is thus translated into a movement of the pump tappet  20  along the longitudinal axis L via the cams  71 , which run in the link  23  of the pump tappet  20 , and via the second anti-rotation device  22  of the pump tappet  20 , which is guided in the first anti-rotation device  43  of the shaft  50   b . Due to the axial movement of the pump tappet  20 , the first stop  24  of the pump tappet  20  comes into contact with the O-ring  30 . The O-ring  30  is then moved together with the pump tappet  20  in the direction of the tank  40 . 
       FIG. 2 b    shows a condition in which the pump tappet  20  has been moved in the direction of the tank  40 . Due to the movement of the pump tappet  20  and the filling of the pump cage  42  with the viscous substance, the plug  80  has also been moved in the direction of the tank  40  and now closes the first connecting channel  41  between the tank  40  and the pump cage  42 , which was still open in the position according to  FIG. 2 a   . Since as already mentioned pressure is exerted on the viscous substance in the pump cage  42  by the movement of the pump tappet  20  in the pump cage  42 , this movement of the O-ring  30  in the direction of the tank  40  is also referred to as pressure stroke. This movement performed by the pump tappet  20  in the pressure stroke results in a displacement of the O-ring  30  to the left in relation to the pump tappet in  FIG. 2 , whereby the second connecting channel  21  is opened. In this way, the pressure built up in the pump cage  42  is reduced by conveying the viscous substance through the second connecting channel  21  via the tappet bore  26  to the applicator  2 . 
       FIG. 2 c    shows a condition in which the pump tappet  20  has been pushed as far as possible into the pump cage  42 . The maximum movement of the pump tappet  20  in the direction of the longitudinal axis L is referred to as the axial stroke and is determined by the curve shape of the link  23 . Due to the design of the link  23 , for example sinusoidal, as shown in  FIGS. 4 a  and 4 b   , a further rotation of the cartridge  50   a  in the direction of rotation results in a change in the direction of the movement of the pump tappet  20 , which now moves in the direction of the applicator  2 . Due to the static friction between the O-ring  30  and the cylinder  10 , the O-ring  30  is only moved in the direction of the applicator  2  when the second stop  24   b  comes into contact with the O-ring  30 . As a result, the second connecting channel  21  is closed by the O-ring  30  enclosing the pump tappet  20 . Thus no further viscous substance can enter the tappet bore  26  (see  FIG. 2 d   ). 
     If the cartridge  50   a  is rotated further, the condition shown in  FIG. 2 e    is achieved. The movement of the O-ring  30  within the cylinder  10  towards the applicator  2  creates suction and thus a vacuum in the pump cage  42 . This vacuum causes a movement of the plug  80 , also in the direction of the applicator  2 . This opens the first connecting channel  41  and the vacuum is balanced by sucking viscous substance from the tank  40  into the pump cage  42 . This movement is therefore also referred to as suction stroke. The pump cage  42  is thus filled with fresh substance from the tank  40  for the next pump cycle. In addition, the drag piston  60  is trailed through the vacuum. If the cartridge  50   a  is now further rotated around the longitudinal axis L, the application device again reaches the operating condition according to  FIG. 2 a    and the pump cycle starts again. 
     The second exemplary embodiment of the invention shown in  FIGS. 9 to 11   b  corresponds to the first exemplary embodiment except for the fact that the plug  80  (first closing device) specified separately in the first exemplary embodiment is designed in one piece with the pump tappet  20  in the second exemplary embodiment. The number of parts is therefore reduced accordingly. 
     The function is, however, substantially the same, wherein in the operating condition according to  FIG. 10 d   , however, the two connecting channels  41  and  21  are both closed at the same time, such that only a vacuum is built up. Only at the last moment, i.e. in the operating condition according to  FIG. 10 e   , is the connection to the tank  40  opened again and the vacuum replenishes the substance. In contrast to this, in the first embodiment, the mechanism in the substance to be conveyed moves the plug  80  already in the state according to  FIG. 2 d   , which is why substance is conveyed all the way from the state according to  FIG. 2 d    to the state according to  FIG. 2   e.    
     The features of the invention disclosed in the above description, the claims and the drawing can be essential for the implementation of the invention in its various embodiments, both individually and in any combination.