Abstract:
A device for expressing milk from one or more breasts has at least one, and preferably two expressers and a pump. The expressers each have a cup for fitting on the breasts and a cup outlet to which a vacuum created by the pump can be connected. The cups have a flexible liner which collapses around the breast to establish the vacuum. Pulsating pressure is applied to the outside of the liner to increase the vacuum and stimulate milk production. The pressure is applied through lines which are vented to maintain adequate, consistent pressure pulses without stalling the pump.

Description:
[0001]    This is a continuation-in-part of Ser. No. 09/715,990, filed Nov. 17, 2000, which is a continuation-in-part of Ser. No. 09/591,981, filed Jun. 12, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to apparatus for extracting milk, and more particularly, to breast pumps which are convenient and comfortable to use.  
         BACKGROUND OF THE INVENTION  
         [0003]    Pumps for expressing milk from breasts are well-known. One known breast pump is disclosed in Whittlestone U.S. Pat. No. 4,607,596.  
           [0004]    The whittlestone patent discloses a breast pump having two milk collectors connected to a pump which applies both a vacuum and pulsating pressure to the breasts to extract milk. The pulsating pressure reciprocates between positive and negative (vacuum) pressure. The pulsating pressure gently massages and compresses the breasts to stimulate milk production, and the vacuum secures the milk collectors to the breasts and helps draw the milk and collect it. The pulsating pressure actually cyclically increases the vacuum level at the breast(s), which further stimulates milk production. However, the pressure is not relieved during pulsation in the Whittlestone patent, so pressure can build to a level sufficient to stall a small motor in a well-sealed system. In addition, the amplitude of the pressure pulses can be reduced by pressure build-up, which is also undesirable. Thus, there is a need for breast pumps that use pulsation as well as vacuum to draw milk, and have controlled relief of the pressure during operation.  
           [0005]    In the Whittlestone device, milk from the two collectors is commonly drawn into a first collection vessel, and then a second collection vessel. The milk is drawn through vacuum lines, though, which makes cleaning difficult. Accordingly, there is a need for breast pumps which are more sanitary and easier to clean than the Whittlestone device.  
           [0006]    The Whittlestone patent discloses a breast cup having a housing, a relatively soft inner ring or donut, and a flexible liner. The liner wraps around the outlet of the cup, and a bung is inserted into the cup outlet to pass the vacuum and milk. At the inlet side, the liner is simply folded over the outside of the housing. This design has limitations. The liner is not accurately aligned and reliably sealed on the inlet side, so moisture and other contaminants can get inside the liner, which is undesirable. At the outlet, the nipple can contact the bung and the liner can collapse around the breast, which can be uncomfortable, and can cause unnecessary trauma, including potential abrasion at the tip of the nipple. Accordingly, there is a need for breast pumps having cups which better fix the liner to the housing. There is also a need for breast pump cups which protect at least the end of the nipple from discomfort due to pulsating pressure.  
           [0007]    The breast pump disclosed in the Whittlestone patent is a diaphragm pump operated by an electric motor. Rotation of the motor shaft is translated into back and forth action by a somewhat large and cumbersome linkage which moves the diaphragm. This adds not only size but weight to the pump, as well. Moreover, the motor must be fairly large, in part because a high vacuum is needed for cleaning purposes, and to maintain adequate vacuum and pressure if the system is leaky. These are problems because convenient storage and portability are desirable to breast pump users. Thus, there is a need for breast pumps which are lighter and smaller than known devices.  
           [0008]    Accordingly, one object of this invention is to provide new and improved apparatus for extracting milk from breasts.  
           [0009]    Another object is to provide new and improved breast pumps which are more convenient and comfortable to use.  
           [0010]    Another object is to provide new and improved breast pumps that use both vacuum and pulsation pressure to collect milk, and control the pulsation pressure to maintain consistent, predetermined increases in the vacuum as the milk is collected.  
           [0011]    Still a further object is to provide new and improved breast pumps which are more sanitary, easy to clean and easy to disassemble and re-assemble in the field.  
           [0012]    Yet another object is to provide new and improved breast pumps which are relatively light, compact and portable.  
         SUMMARY OF THE INVENTION  
         [0013]    A device for expressing milk from one or both breasts has at least one milk collector and a pump. Preferably, the device has first and second collectors (also called expressers), so that both breasts can be milked simultaneously. Each expresser has a cup assembly which fits on the breast, a pulsation port to which a supply of pressurized pulsating air is connected, and a vacuum port to which a vacuum supply is connected. The pulsating air and vacuum are created by the pump. In use, pulsating air causes massage and gentle compression of the breast and stimulates milk production, while the vacuum secures a liner in the collector on the breast and expresses the milk from the breast. Among other things, the pressure pulses increase the vacuum at the breast.  
           [0014]    Both vacuum and pulsating air pressure are fairly well controlled by adequately sealing the various parts of the device and providing a pressure release vent for the pressurized air supply to each expresser. A vacuum adjustment is also provided.  
           [0015]    The collectors also include a cap and manifold which direct the vacuum and pressure, a cup assembly which is preferably press fit onto the manifold, a collection vessel secured to the bottom of the manifold, and, if desired, a one-way check valve or the like between the manifold and the collection vessel. After passing through the vacuum adjustment, the vacuum is directed through the cap and manifold, collection vessel and cup assembly so that the milk is drawn into the collector with little or no milk entering the vacuum lines to the pump. A filter may be provided for added isolation of the vacuum pump and vacuum lines, if desired.  
           [0016]    The cup assembly includes a bell housing, a relatively soft donut shaped pad, and the flexible liner, preferably made of silicone, nitrile or other suitable material that meets requirements for medical materials. The liner is secured to the inlet side of the cup assembly by a locking type of attachment, and extends around the bottom or lower end of the bell housing, where it is secured by another locking press fit configuration.  
           [0017]    The bottom end of the cup assembly fits into a receptacle in the manifold. The receptacle has a hollow boss which extends into the cup assembly by a desired distance. The hollow portion inside the boss increases the area for extension of the nipple during milk expression, avoiding potentially uncomfortable contact at the nipple area. The boss also prevents the liner from collapsing around the end of the nipple during use, and keeps the throat of the cup assembly open for milk flow.  
           [0018]    The collector can be easily disassembled and cleaned in a dishwasher or the like, by removing the collection vessel and using or storing the milk, removing the cap and then removing the cup assembly. The cup assembly can be cleaned without removing the liner, if desired, or the liner can be removed and cleaned separately, or replaced. A cleaning cap can be placed over the air pulsation port of the cup assembly when the cup assembly is cleaned in its assembled condition, to prevent water from entering the space between the liner and the bell housing. A valve could be used in place of the cap for this purpose, if desired.  
           [0019]    The manifold, cap and valve can also be washed. The cup assembly can be easily reassembled after cleaning by reinserting the cup assembly in the manifold, reattaching the cap to the manifold and cup assembly, and securing another collection vessel to the bottom of the manifold, with or without the check valve.  
           [0020]    The pump includes a movable diaphragm in a chamber. The diaphragm is oscillated back and forth by a relatively small linear actuator device such as a stepper motor. The motor preferably is a self-contained system that moves its final object axially. The motor can have a shaft which does not rotate, but moves back and forth axially. The shaft of the motor is directly or nearly directly linked to the diaphragm, which eliminates complex and cumbersome linkage components, reducing the size and weight of the pump. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    The above mentioned and other features of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood with reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:  
         [0022]    [0022]FIG. 1 is a partially cut-away perspective view of apparatus made in accordance with the principles of this invention;  
         [0023]    [0023]FIG. 2 is a milk collector used in the apparatus of FIG. 1, shown in cross-section;  
         [0024]    [0024]FIG. 3 is a top view of the milk collector of FIG. 2, taken along lines  3 - 3  in FIG. 2;  
         [0025]    [0025]FIG. 4 is an exploded view of a cup assembly used in the collector of FIG. 2;  
         [0026]    [0026]FIG. 5 is an exploded view of the collector of FIG. 2;  
         [0027]    [0027]FIG. 6 is a cut-away view of the collector of FIG. 2, showing the liner in a collapsed condition;  
         [0028]    [0028]FIG. 7 is a graph showing the effect of pressure pulsation on the vacuum at the liner of the collector of FIG. 2;  
         [0029]    [0029]FIG. 8 is a cut-away view of an alternate embodiment of the pump used in the apparatus of FIG. 1;  
         [0030]    [0030]FIG. 9 is a block diagram of a control system for the apparatus of FIG. 1;  
         [0031]    [0031]FIGS. 10 and 11 are diagrams of an alternate embodiment of the diaphragm used in the pump in the apparatus of FIG. 1; and  
         [0032]    [0032]FIG. 12 is a cutaway view of a connector used in the apparatus of FIG. 1. 
     
    
     DETAILED DESCRIPTION  
       [0033]    Referring to FIG. 1, apparatus  10  is provided for expressing milk from one breast, or from two breasts simultaneously. The apparatus  10  includes a first collector or expresser  12  and a second expresser  14 . It is likely that both expressers would generally be used, but only one expresser could be used, if desired, preferably by disconnecting the vacuum line from the unused expresser and covering the unused vacuum port of the pump with a cap (not shown).  
         [0034]    A pump  16  is connected to both expressers  12 ,  14  through vacuum lines  18 ,  20 , and air pressure lines  22 ,  24 . The vacuum and pulsation lines can be configured in any suitable way. In FIG. 1, vacuum hoses  18   a,    20   a  and pressure hoses  22   a,    24   a  are connected to the pump  16  and a connector  17 . Vacuum hoses  18   b,    20   b  and pressure hoses  22   b,    24   b  are connected to the other end of the connector  17  and the expressers  12 ,  14  with adapters  23  (FIGS. 2, 3), if needed. The connector  17  has openings for the lines  18 ,  20 ,  22  and  24 , and a throat  19  which connects the vacuum lines  18 ,  20  to each other, creating a common vacuum at the expressers  12 ,  14 , as seen in FIG. 12. A threaded needle valve  21  in the throat  19  permits easy adjustment of the vacuum by venting atmospheric air into the system as desired. The connector  17  can be secured to a housing, if desired, to provide easy vacuum and pressure transmission through the housing.  
         [0035]    The pump  16  creates a vacuum which engages the breasts, and contributes to drawing the milk from the breasts. The pump also creates reciprocating compression and release pressure pulsation around the areola and some or all of the nipple, as will be seen. The pump  16  can be powered by line voltage, a battery, manually or the like.  
         [0036]    The expressers  12 ,  14  are shown in greater detail in FIGS. 2, 3 and  5 . Each expresser includes a manifold  26 , a cup assembly  28  which fits over a breast, a cap  30 , a filter  31  (FIG. 5), a sealing device  33   a  such as a wipe washer, o-ring or the like, and a collection vessel  34  . Gaskets  33   b  and  33   c  are also included, to better seal the vacuum system. A valve  36  can be included, though it is not necessary. The collection vessel can be a bottle made of plastic-like material or the like or a bag, and can be oriented at an obtuse angle with respect to the cup assembly, as shown.  
         [0037]    The manifold  26  includes an opening  38  which is preferably threaded, so that a collection vessel such as a plastic milk bottle can be threadedly secured to the manifold  26 , with the valve  36 . The valve  36  is preferably a one-way check valve such as a duck bill valve or the like. When using the valve  36 , the gasket  33   c  is not needed because the valve  36  seals the opening  38 . A vent  37  in the manifold  26  is helpful because it keeps the collection vessel  34  at atmospheric pressure when the valve  36  is used. However, it is also possible to eliminate the valve  36 , in which case there is also no need for the vent  37 .  
         [0038]    A vacuum is applied to the expresser through a port  42  in the cap  30 , and is drawn through a vacuum path in the manifold  26  through an outlet opening  44  in the top of the manifold. The vacuum is drawn through an internal orifice  46  to the opening  38  in the midsection of the vacuum path, which is beneath the port  42  and the cup assembly  28 . The vacuum tends to close the valve  36 , which in conjunction with the vent  37 , prevents a substantial buildup of vacuum in the collection vessel  34 .  
         [0039]    The vacuum is drawn from the opening  38  to a manifold vacuum inlet  40  through a channel  50 . The vacuum inlet  40  forms a cup assembly opening that is in communication with a milk outlet port  48  in the cup assembly  28 . When milk is drawn from the breast, the milk passes through the channel  50  under the force created by the vacuum, but most of the milk drops into the valve  36  through the force of gravity, and does not enter the orifice  46 . Cleaning is easier because milk is not drawn into the vacuum path beyond the collection vessel  34 . When sufficient milk collects in the valve  36 , the weight of the milk forces the valve open, which releases the milk into the collection vessel  34 . Because the milk falls down, the vacuum lines are not contaminated. In this manner, the milk is collected without contaminating the vacuum lines  18 ,  20  (FIG. 1).  
         [0040]    The cup assembly  28  has a milk inlet port  52  in addition to the outlet port  48 . The components of the cup assembly  28  include a bell housing  54 , a donut shaped pad  56 , and a flexible liner  58 , shown disassembled in FIG. 4. The cup assembly  28  also has an air pressure pulsation port  60  which forms part of a pressure path and allows pressurized air to enter a space  62  between the case bell housing  54  and the liner  58 .  
         [0041]    The cup assembly  28  is assembled by placing the donut shaped pad  56  in the housing  54  as shown, and does not need further securement. The pad  56  is preferably made of a suitable foam material which is sized to fit snugly in the housing  54 . However, the pad  56  can be easily removed by placing a finger through the opening in the ring and pulling the ring out.  
         [0042]    The liner  58  is installed in the cup assembly  28  by securing an end  63  to the liner  58  in a groove  64  formed in the housing  54  (FIGS. 2, 3 and  4 ). The end  63  and groove  64  are shaped to provide locking press fit type of securement. The liner could also be affixed to the housing  54  by heat or chemical bonding.  
         [0043]    The liner  58  extends from the groove  64  over and around the pad  56  and inside of the housing  54  to a bottom end  66  of the housing  54 . An end  68  of the liner  58  is inserted into a groove  70  near the end  68  for securement in a press fit fashion. The liner  58  can be any suitable shape, including the shape shown in FIG. 2, which includes a relatively narrow section  72  near the inlet opening  52 , and a wider section  74  between the section  72  and the outlet end  48  of the cup assembly  28 . This shape places more pressure around the areola region of the breast, while placing less pressure on the nipple itself. By sealing the liner to the case at both ends, the assembly can be washed without taking the liner off, if a cleaning cap  75  is placed over the pressure inlet  45  (FIG. 4).  
         [0044]    The cup assembly  28  can be press fit into a circular groove  76  in the manifold  26 , seen in FIG. 5. The groove  76  is formed by an outside wall  78  and an inside boss  80 . The boss  80  can extend outwardly as far as desired, and can be any suitable shape, such as circular, triangular, square, rectangular, elliptical, hexagonal, etc. Since the boss  80  is hollow and prevents the liner  43  from collapsing under outside air pressure, the boss  80  protects any part of the nipple which is inside the boss from a pinching action caused by pressure when the liner is collapsed, as seen in FIG. 6. Abrasion is avoided because there is more room for breast extension during milk expression. The boss  80  also keeps the throat of the cup assembly open, so that the flow of milk is not inhibited.  
         [0045]    The cap  30  (FIGS. 2, 3 and  5 ) includes an air pressure/pulsation channel  82  which extends from a pressure inlet  84  to the port  60 , as well as the port  42  for the vacuum path. The cap  30  can be press fit over the manifold opening  44  and the cup assembly air pressure/pulsation port  60 , and can be easily removed. When installed, the cap  30  further secures the cup assembly in the manifold, but both the cap and the manifold can be removed without tools for cleaning purposes.  
         [0046]    The filter  31 , if used, further prevents liquids, fats and solid components in the milk from entering the vacuum lines and the pump. The filter  31  is preferably permeable to air flow when dry and also when wet, which can happen if milk contacts the filter. Thus, if the filter becomes wet due to milk and/or water, air can still pass through the filter because the filter remains permeable to air. An example of such a filter is Versapor R1200 (part no. 66393) by Pall Corp.  
         [0047]    Referring again to FIG. 1, the pump  16  has two halves  104 ,  106  secured together by screws or the like  108  to form a chamber  110 . The screws  108  also secure a movable diaphragm  112  in place. The diaphragm  112  divides the chamber  110  into two halves  110   a,    110   b.    
         [0048]    The diaphragm  112  is oscillated in a back and forth manner by a motor  114 . About 41-65 pulsations per minute at the breast (one pulsation being the result of both a back and forth motion of the diaphragm) are believed to produce suitable results, with about 52 pulsations per minute producing good results. The motor can be secured to the housing by bolts  116  or the like.  
         [0049]    The motor  114  can be a stepper motor, which is one form of a linear actuator, which has a shaft  118 . The shaft  118  moves in and out of the motor  114  in the axial direction without rotation. The shaft  118  is threaded, and is moved by a rotating threaded ring  120 , which is similar to a nut. Rotation of the ring  120  moves the shaft  118  linearly. In this manner, the shaft  118  can move the diaphragm  112  back and forth essentially directly, without large, complex linkages.  
         [0050]    The distal end of the shaft  118  can be guided by an opening  122  in an end cap  124 . The end cap  124  is secured by bolts  126 .  
         [0051]    The pump  16  also has vacuum outlets  128 ,  130  in the chamber  110 , on opposite sides of the diaphragm  112 . The vacuum lines  18 ,  20  are connected to the vacuum outlets  128 ,  130 . Check valves such as duck bill valves  136 ,  138  control the vacuum and pumping operation, and exhaust valves  140 ,  142  release the pressure created in the chamber halves  110   a,    110   b  by the movement of the diaphragm  112 . However, some of the pressure generated by the diaphragm is transmitted through the pressure lines  22 ,  24  to the collectors  12 ,  14 . The pressure forces the liners  58  against the breasts (see FIG. 6), which further stimulates release of milk. While the vacuum is fairly continuous, though, the pressure pulsates, in part because the pressure is quickly bled through vents  143  in the pressure lines  22 ,  24 . In fact, when the diaphragm moves away from a pressure line  22 , or  24 , air is drawn out and a partial vacuum can be created.  
         [0052]    [0052]FIG. 7 shows the effect of adequately vented pulsation pressure on the vacuum supplied to the liner. The pump  16  generates a vacuum V SYS . Without pulsation pressure, the vacuum is fairly steady at V SYS . When pressure pulses are applied to the outside of the liner, though, the vacuum periodically increases to V PEAK . Those periodic increases stimulate milk production with less discomfort and a lower V SYS  than is needed if pressure pulses are not applied.  
         [0053]    Preferably, a minimum V SYS  of 0.5″ mercury is maintained during use, and the maximum vacuum V PEAK  does not exceed 5″ mercury. The maximum vacuum V PEAK  is preferably 3.0″-4.1″ mercury. However, the maximum differential between V SYS  and V PEAK  is preferably between 1″ and 4.5″ mercury. The vents  143  are sized to obtain a desired V PEAK , and avoid stalling due to overload. If the vents are too small, V PEAK  will be too high and stalling could occur. If the vents are too large, V PEAK  will be too low.  
         [0054]    The device is light weight, portable and compact because large motor linkages are eliminated. Wear is also reduced by simplifying the power train in this manner. The motor  114  can be any suitable device which creates a fairly self-contained drive system which is relatively small in size and fairly quiet. In fact, the motor can be an ordinary motor  114  with a threaded rotating shaft  146 , as seen in FIG. 8. In that embodiment, a fixed ring  148  is attached to the diaphragm. The ring  148  is also threaded, so when the shaft  146  rotates clockwise and counter-clockwise, the diaphragm  112  moves back and forth.  
         [0055]    The motor can be controlled in any suitable manner, such as the control system  150  shown in FIG. 9. An application specific integrated circuit or the like has a microprocessor  152  and a ROM  154 , programmed to cause a motor driver  156  to set the desired rate of rotation and the direction of rotation of the motor. The rotation rate, as well as the timing of the back and forth motion of the diaphragm, can be controlled in this manner.  
         [0056]    The diaphragm  112  can be any suitable configuration, such as that shown in FIG. 1, which features a flat stiff middle section flanked by soft corrugations. Another design is shown in FIGS. 10 and 11, where a diaphragm  158  has a plurality of rings  160  joined by corrugations  162 .  
         [0057]    In use, power is applied to the pump  16 , and the expressers  12 ,  14  are placed over the breasts. The vacuum V SYS  created by the pump  16  secures the expressers  12 ,  14  on the breasts and helps draw milk from the breasts. The pressure pulsations massage and compress the breasts to stimulate milk production, and reduce the amount of vacuum needed to collect the milk. The air pressure lines are vented to obtain strong pulses without overloading the system. This reduces discomfort to the breasts. The device can be easily disassembled without tools, cleaned and reassembled.  
         [0058]    The many advantages of this invention are now apparent. The pulsation pulses stimulate milk production, without overloading the system due to excessive pressure build-up in the pressure lines. Cleaning is more convenient because milk does not enter the vacuum lines. Moreover, the entire collector can be easily disassembled for cleaning and reassembled without tools. The bosses in the expressers protect the end of the nipple from irritation, which is comfortable. Moreover, the entire pump is small, lightweight and relatively quiet.  
         [0059]    While the principles of the invention have been described above in connection with a specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention. For example, various aspects of the invention could be used to milk animals, as well as humans.