Abstract:
An electric breast pump utilizes an electric motor to drive a piston vacuum pump to draw a negative pressure or suction up to 250 mm Hg at a flexible collapsible breast cup. The suction cycles between the set maximum and atmospheric under the control of a magnetic valve that is opened and closed by a vacuum sensor. The valve opens and closes a bypass to atmosphere. The speed of the electric motor can be selectively varied to increase the frequency of the suction cycles, which can vary between 20 to 44 cycles per minute. The breast cup collapses during a part of each cycle to simulate the peristaltic action of a suckling infant.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. provisional application Ser. No. 60/084,054 for PJ&#39;s Comfort Electric Breast Pump and Soft Breast Cup, filed on May 4, 1998, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to improvements in breast pumps, and more particularly pertains to new and improved electric breast pumps wherein the breast pump both expresses and collects breast milk. 
     2. Description of Related Art 
     In the field of breast pumps for expressing breast milk it has been the practice to employ hard breast cups and maximum suction to the human teat to express the breast milk. Such devices have not been entirely satisfactory in that if the suction generated by the breast pump is too high, bruising will be caused to the areola and nipple. In addition, the amount of milk volume obtained in response to a constant average suction is quite low compared to that obtained by a suckling infant. A breast feeding infant, in addition to applying suction, compresses the teat against his hard palate and uses the peristaltic action of the tongue. A research study entitled  Comparing Breastfeeding and Breast Pumps Using a Computer Model,  published in the Journal of Human Lactation, 1997, Vol. 13, pp. 195 to 202, by Christopher Xoppou, Ph.D., et al., concluded that a large increase in milk flow can be obtained when both cyclic suction and peristaltic force is used on the human teat. The present invention simulates an infant suckling by utilizing both peristaltic forces and cyclic suction. 
     SUMMARY OF THE INVENTION 
     The objects of the present invention are achieved by use of soft breast cups made of durable, yet flexible, plastic material that collapse around the human teat during a portion of each suction cycle. Suction is created by an electric motor driving a piston vacuum pump that draws a continuous suction airflow. The suction cycle is caused by a magnetic valve controlled by a vacuum sensor that causes the valve to open the vacuum line to atmosphere when a pre-set maximum pressure is reached and closes again when pressure is released. Motor speed and maximum pressure is selectable by the user. The suction may be adjusted between 150 mm Hg to 250 mm Hg. The motor speed is adjustable between these different speeds to vary the suction frequency from about 20 to 44 cycles per minute. The suction and cycle adjustment, along with the flexible, collapsing cups, provides for greater comfort and optimized milk flow. Besides collection bottles, one for each of the two breast cups, the system uses a catch bottle in the suction tube, before it is connected to the vacuum pump, to catch any breast milk that happens to accidentally flow past a collection bottle. The catch bottle prevents the breast milk from entering the vacuum pump. Milk flow into the catch bottle will trigger a light sensor that causes the motor to stop. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The exact nature of this invention, as well as its objects and advantages, will become readily apparent from consideration of the following specification as illustrated in the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof, and wherein: 
     FIG. 1 is a perspective illustration of the basic elements of a preferred embodiment of the present invention; and 
     FIG. 2 is a block diagram showing the operative elements of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor for carrying out the invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the basic principles of the present invention have been defined herein specifically to provide an electronic inductor circuit suitable for high-speed modem applications. 
     Referring now to FIG. 1, the breast pump  11  of the present invention is illustrated as contained within a housing  13 , preferably made of a lightweight plastic, having a handle  15  to facilitate easy movement of the breast pump  11 . The housing  13  has a tray  17  mounted to its front which contains a pair of bottle holder apertures  45  for holding a catch bottle  19  and additional collection bottles, as desired. 
     Two breast cups  41 ,  43  may be advantageously used with the breast pump of the present invention. Each breast cup  41 ,  43  is made of a soft flexible, but sturdy, plastic material which is shaped to comfortably fit over the human teat and a portion of the breast. Each breast cup is associated with a collection bottle. Breast cup  41  is connected to a vacuum tube  27  by a tube connector  29  that also connects to the interior of collection bottle  35  by a removable bottle cap  39 . Flexible breast cup  43  likewise is connected to collection bottle  33  by removable bottle cap  37 , both of which are connected to a tube connector  31 . Tube connector  31  is connected to vacuum line  32 . Vacuum line  27  from breast cup  41  and line  32  from breast cup  43  are both connected to a Y-connection  25  which connects both lines  27 ,  32  to a vacuum line  34  leading to tube connector  23  which is connected to removable bottle top  21 . Connector  23  is also connected to vacuum tube  53  which leads to a vacuum pump, which will be discussed hereinafter. Removable bottle top  21  is sealably attached to catch bottle  19 . A light sensor is located on the underside of bottle top  21 , positioned to detect the passage of fluid into the catch bottle. 
     Housing  13  of breast pump  11  carries a pair of adjustment knobs  47  and  51  and an “on” light  49 . Adjustment knob  47  controls the speed of the electric motor inside housing  13  which drives the vacuum pump, also inside housing  13 , thereby varying the suction cycles administered to the human teat by the vacuum being drawn through the breast cups  41 ,  43 . The other adjustment knob  51  is a vacuum or suction adjustment which allows the user to set the maximum continuous suction or vacuum being applied to the human teat within the breast cups  41 ,  43 . By providing both a user-settable cycle adjustment and vacuum adjustment, the breast pump of the present invention can be adjusted by the user to provide for the greatest amount of comfort and maximum milk flow. 
     Vacuum adjustment knob  51  allows the user to select from a range of maximum suction levels from about between 150 mm Hg to 250 mm Hg, which is continuously generated at the breast cups  41 ,  43 . The cycle adjustment knob  47  allows the user to adjust the speed of the motor driving the vacuum pump. This tends to vary the number of suction cycles per minute administered to a human teat by the suction cup  41 ,  43 . The preferred frequency range of cycles is between 20 to 44 cycles per minute. During each cycle, the breast cup  41  collapses around the human teat when suction reaches its maximum, as set by the user by knob  51 , and recovers again during the period of the cycle that the vacuum line  53  is vented to the atmosphere. 
     The elements of breast pump  11  contained within housing  13  are a 12-volt electric motor  61  (FIG. 2) that is powered by a power converter  57 , that may be connected to a 115-volt 60 Hz outlet and provides a 12-volt DC source over line  59  to motor  61 . Motor  61  drives a piston vacuum pump  63  which has a vacuum intake line  75  and an exhaust line  67 . Exhaust line  67  is vented to the atmosphere through a filter  65  which is preferably a hydrophobic PTFE membrane filter or any other filter capable of controlling particle size of 0.02 microns. Vacuum intake line  75  for a piston vacuum pump  63  is connected to a vacuum sensor  73  which senses the maximum suction in vacuum line  53 , which is connected to the breast cups  41 ,  43  (FIG.  1 ). Vacuum sensor  73  is preferably an electronic difference pressure sensor, or any other device which can readily detect the maximum pressure or suction in the vacuum line  53 . An electromagnetic valve  69  is connected to vacuum line  53 , in a bypass loop to piston pump  63 . The bypass loop is made up of vacuum line  44  at its intake, and vacuum line  71  at its outlet, which is connected to outlet line  67  leading to the atmosphere through filter  65 . 
     Vacuum sensor  73  is adjustable by adjustment knob  51 . Electric motor  61  is likewise adjustable by adjustment knob  47 . In addition, motor  61  is turned off over control line  76  whenever light sensor  74  in the catch bottle detects that fluid is flowing into catch bottle  19 . 
     The breast pump of the present invention provides both a cyclic suction and peristaltic forces, the combination closely resembles the suckling of an infant. The result is an increase in milk volume over prior art breast pumps, while allowing the user to adjust the breast pump for the greatest degree of comfort. 
     The cycling of the continuous suction air flow is the result of the magnetic valve  69  which is controlled by the electronic vacuum sensor  73 . The magnetic valve  69  opens or closes a bypass line  44 ,  71  to atmosphere through exhaust line  67  and filter  65 . Each time the magnetic valve  69  opens, vacuum line  53  exhausts to the atmosphere, causing the breast cups  41 ,  43  to recover from the collapsed state. When vacuum sensor tells electromagnetic valve  69  to close, the motor and piston vacuum pump drive the suction in vacuum line  53  back up to its set maximum, causing breast cups  41 ,  43  to collapse. Once maximum suction is reached, vacuum sensor  73  again tells valve  69  to open, exhausting the suction in vacuum line  53  to atmosphere once again. The cycle frequency may be varied from about 22 cycles per minute to 44 cycles per minute, depending on whether one or two collection bottles are in the vacuum circuit, the speed setting for motor  61 , and the maximum vacuum setting for vacuum sensor  73 . The faster the motor  61  is driving piston pump  63 , the faster maximum suction is obtained in vacuum line  53  and cups  41 ,  43 . The maximum suction setting which can be adjusted continuously between 150 mm of Hg to 250 mm of Hg will also impact the cycle frequency. As the collection bottles  35 ,  33  fill up with breast milk, thereby reducing the volume that needs to be evacuated by the piston vacuum pump  63 , the cycle frequently will increase. 
     What has been described is an electric breast pump that most nearly simulates the suckling of an infant on a human teat by applying both cyclic suction and peristaltic force to the human teat by flexible and collapsible breast cups. Moreover, the maximum suction is readily selectable by the user for optimum comfort. Regardless of the suction level selected, the system prevents the accidental flow of breast milk into the pump. 
     Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described herein.