Abstract:
A removable battery pack is disclosed for a portable medical device, such as an automated external defibrillator. The removable battery pack interacts with the portable medical device using an electrical connector that creates a watertight connection. The connection is created by a gasket that is not compressed in the direction of movement of the removable battery pack. As a result, the gasket does not increase the force necessary to engage the removable battery pack in the portable medical device.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to electronic devices that use replaceable battery packs. More specifically, the invention relates to a waterproof battery pack that interfaces with the electronic device such that a watertight seal is created between the battery pack and the electronic device. 
       BACKGROUND OF THE INVENTION 
       [0002]    External defibrillators are emergency medical devices designed to supply a controlled electric shock (i.e., therapy) to a person&#39;s (e.g., victim&#39;s) heart during cardiac arrest. This electric shock is delivered via pads electrically connected with the external defibrillator and in contact with the person&#39;s body. 
         [0003]    To provide a timelier rescue attempt for a person experiencing cardiac arrest, some external defibrillators have been made portable, by utilizing battery power (or other self-contained power supplies). In addition, many portable external defibrillators have programming to make medical decisions making possible operation by rescuers who are non-medical personnel. 
         [0004]    These portable external defibrillators, commonly known as automated external defibrillators (AEDs), including automatic and semi-automatic variants, have gained acceptance by those outside the medical profession and have been deployed in myriad locations outside of traditional medical settings. Due to the life saving benefits of AEDs, more and more non-medical users are purchasing and deploying AEDs in their respective environments. This allows for a rescue attempt without the delay associated with bringing the person to a medical facility, or bringing a medical facility to the person (e.g., a life support ambulance). 
         [0005]    AEDs use batteries for power. As those skilled in the art will appreciate, when an AED is used, a significant amount of energy is drained from the battery. But also, energy is drained from the batteries even when the AED is perceived to be off by a user. More precisely, AEDs perform a number of self-diagnostic tests to assure they will work when called upon, and, in addition, there is a natural loss of energy simply due to the passage of time. As a result, AEDs typically employ replaceable battery packs (i.e., a single unit containing multiple cells). 
         [0006]    Replacement of batteries, or battery packs, must be user friendly and maintain the integrity of the AED. A significant issue in battery pack replacement is the force that must be exerted on the battery pack to secure it in the AED and/or the integrity of a seal that is needed to avoid infiltration of the battery pack or AED unit by undesirable substances, such as water or dust. 
         [0007]    The present invention is an improved battery pack. Furthermore, other desirable features and characteristics of the present invention will become apparent for the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention is a removable battery pack for a portable medical device, such as an automated external defibrillator. The removable battery pack interacts with the portable medical device using an electrical connector that creates a watertight connection. The connection is created by a gasket that is not compressed in the direction of insertion of the removable battery pack. As a result, the gasket does not increase the force necessary to engage the removable battery pack in the portable medical device making the replacement of the battery pack more user friendly. 
         [0009]    Other features, attainments, and advantages will become apparent to those skilled in the art upon a reading of the description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a front perspective drawing of an automated external defibrillator (AED). 
           [0011]      FIG. 2  is a drawing of the back of the AED shown in  FIG. 1 . 
           [0012]      FIG. 3  is an enlarged drawing of a connection point located in a battery slot on the AED, see circle  3  in  FIG. 2 . 
           [0013]      FIG. 4A  is a cross-sectional view taken along line  4 A shown in  FIG. 3 . 
           [0014]      FIG. 4B  is a cross-sectional view taken along line  4 B shown in  FIG. 3 . 
           [0015]      FIG. 5  is an enlarged view of a gasket groove shown in  FIGS. 4A and 4B , see circle  5  in  FIG. 4B . 
           [0016]      FIG. 6  is a front perspective view of a latch used to secure a battery pack in the battery slot. 
           [0017]      FIG. 7  is a back perspective view of the latch shown in  FIG. 6 . 
           [0018]      FIG. 8  is a perspective view of a battery pack showing the bottom. 
           [0019]      FIG. 9  is an expanded view of the battery pack shown in  FIG. 8  in the area of an electrical connector, see circle  9  in  FIG. 8 . 
           [0020]      FIG. 10  is a cut-away view of the AED in the area of the battery slot proximate a latch, see  FIG. 3  taken along line  10 , showing a battery pack as it initially interacts with the latch when placed in the battery slot. 
           [0021]      FIG. 11  is the same view as that shown in  FIG. 10 , but showing the back pack inserted deeper in the battery slot. 
           [0022]      FIG. 12  is a cut-away view of a gasket positioned on the battery pack interacting with a bearing surface on the AED, see  FIGS. 4A and 4B  for further gasket groove details. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    As shown in  FIG. 1 , a portable automated external defibrillator (AED), generally referred to by reference no.  100 , includes a case  102  having defibrillation electronics and programming therein. Pads (not shown) connect to the AED  100  via a connector  104  (only one-side shown). Portable AEDs are well known in the art. 
         [0024]    The depicted AED  100  is a semi-automatic AED, as a shock is sent to a victim via the pads by depressing a shock button  106 . Also, this illustrative AED  100  has a video display  108  for displaying visual information, such as user instructions, and a speaker  110  for providing audio instructions. 
         [0025]    Continuing with  FIG. 2 , as shown on the back of the AED  100 , a slot  112  is provided for accepting a removable battery pack, discussed below. The slot  112  includes a first part  120 A of the electrical connector  120  (the electrical connector as a whole is referred to by reference no.  120  with elements, in this case parts, that make up the electrical connector being referred to by reference no.  120  with an appropriate suffix, such as A and B), a spring  114 , and a latch  118 . 
         [0026]    The first part  120 A of the electrical connector  120 , which is shown in more detail in  FIG. 3 , as illustrated, includes a gasket groove  122 , depressions  124 , and spring contacts  126 . More specifically, the gasket groove  122  surrounds an opening  128  in the AED  100  wherein the spring contacts  126 , for connecting the battery to the defibrillation electronics, are positioned. 
         [0027]    Continuing with  FIGS. 4A , B and  5 , the gasket groove  122  has a cross-section having a depth D, an opening width OW and a bottom width BW, which is less that the opening width. The gasket groove  122  has sides  130  and a bottom  132 . As a result of the opening width OW being less than the bottom width BW, the gasket groove  122  cross-section is tapered. However, the taper ends above the bottom  132  thereby defining a bearing surface  134 . As illustrated, the bearing surface  134  is generally perpendicular to the bottom surface  132  and located on a side  130  of the gasket groove  122  that is proximate the opening  128 . 
         [0028]    The depressions  124  are positioned around the gasket groove  122  on the side away from the opening  128 . In this illustrative example, there are three depressions. 
         [0029]    As shown in  FIGS. 6 and 7 , the latch  118 , which is located on a side  140  of the slot  112  (See  FIG. 2 ), is designed to interact with the battery pack, discussed below, to secure the battery pack within the slot  112 . The latch  118  includes a pivot  142 , a spring  144 , a latching surface  146 , a first surface  148 , and a second surface  150 . 
         [0030]    The pivot  142  is the point about which the latch  118  is secured to the AED. The pivoting of the latch  118  about the pivot  142  permits the latching surface  146  of the latch  118  to engage and disengage the latching surface, which interacts with the battery pack to secure it in the slot  112 . The spring  144  provides a bias to the latch  118 , making it more user friendly. More specifically, the spring  144  makes the latch  118  self-locking, which is discussed below. 
         [0031]    The pivot  142  has a round bearing surface  152  and holes  154 . Typically in this design, when the latch  118  is pivoted it rides on the bearing surfaces  152 . The holes  154  provide a passage for an axle (single or multi-part), which would positively secure the latch  118  to the AED  100 . Each bearing surface  152  could be snapped into cooperating openings (not shown) in the AED  100 . It should be appreciated that either or both of the above structures could be used. 
         [0032]    Continuing with  FIG. 8 , a battery pack, generally referred to by reference number  155 , includes a container  156  for holding a number of cells (not shown), a second part  120 B of the electrical connector  120  of the electrical connector  120 , and abutment surfaces  166 . 
         [0033]    As shown in  FIG. 8  and in greater detail in  FIG. 9 , the second part  120 B of the electrical connector  120  includes a gasket  160  and a second set of contacts  162 . The second set of contacts  162 , in this case fixed surfaces, cooperate with the spring contacts  126  to connect the battery pack  155  to the AED. Both the second set of contacts  162  and the spring contacts  126  conduct electricity. 
         [0034]    The gasket  160 , which is a rubber, such as urethane, can be surface mounted or in a groove. Additional characteristics of the gasket  160  are discussed below. 
         [0035]    The second part  120 B of the electrical connector  120  further includes a guard  164 , which projects outwardly from the container  156 . The illustrated guard  164 , which has multiple posts, has a height sufficient to protect the gasket  160 , which also projects outwardly from the container  156 . More precisely, the height of the guard  164  is such that the guard can rest on a surface, such as a table, and the gasket  160  will not touch the surface. In essence, the guard  164  protects the gasket  160  from being damaged when the battery pack  155  is not within the slot  112 . 
         [0036]    The abutment surface  166  on the battery pack  155  cooperates with the abutment surfaces  146  on the latch  118  to secure the battery pack in the AED. 
         [0037]    As shown in  FIG. 10 , the abutment surface  146  on the latch  118  projects outwardly from a wall  168  of the slot  112  as a result of the spring  144 . Upon insertion of the battery pack  155  into the slot  112 , the battery pack travels down into the slot and impacts the latch  118 . As the latch  118  is impacted, it rotates about its pivot  142  so the battery pack  155  can continue downward in the slot  112 . 
         [0038]    At some point, a surface  168  (see  FIG. 10 ) of the battery pack  155 , in this case the bottom surface, will impact the spring  114  (see  FIG. 2 ). Additionally, at some point the contacts  126  (see  FIG. 8 ) of the electrical connector  120  will impact the spring contacts  126  (see  FIG. 2 ). To allow for a generally parallel descent of the battery pack  155  into the slot  112 , the spring  114  and the spring contacts  126  should be engaged approximately simultaneously. It should also be appreciated that the spring  114  and spring contacts  162  are separated by the abutment surface  166  (see  FIG. 8 ) which further supports creating a generally parallel descent. 
         [0039]    Continuing with  FIG. 11 , the abutment surfaces  166  on the battery pack  155  will pass the abutment surfaces  146  on the latch  118 . As the abutment surfaces pass, the spring  144  on the latch  118  will force the abutment surfaces  146  on the latch  118  to engage the cooperating abutment surfaces  166  on the battery pack  155 . This engagement secures the battery pack  155  in the slot  112 . 
         [0040]    Continuing with  FIG. 12 , which shows the gasket  160  in its final position on the bearing surface  136 , as the descent of the battery pack  155  continues but prior to the engagement of the abutment surfaces, the gasket will engage the bearing surface. To assure the best fit possible of the gasket  160  against the bearing surface  136 , as an edge  170  of the gasket initially contacts the bearing surface, the gasket should distend laterally outward (i.e., away from the bearing surface). As the edge  170  of the gasket  160  continues down the bearing surface  136 , the characteristics of the material from which the gasket is made should allow the gasket to conform to the bearing surface. Thus, there could be a slight lateral compression of the gasket  160  (i.e., the thickness of the gasket in the area where it is in contact with the bearing surface may be slightly less than the area where it is not). 
         [0041]    As shown in  FIG. 12 , when the gasket  160  conforms to the bearing surface  136  it creates a watertight seal along the bearing surface. As a result, water cannot enter the AED  100  through the electrical connection  120  when a battery pack  155  is installed. In addition, the placement of the gasket  160  between the bearing surface  136  and any water seeking entry into the AED  100  means that water pressure with further increase the integrity of the seal. 
         [0042]    Further, as shown in  FIG. 12 , to avoid compressing the gasket  160  (i.e., reducing its height), which would added resistance to inserting the battery pack  155 , the height of the gasket  160  should be less than the depth of the gasket groove  122 . Thus, the gasket  160  should not bottom out in the gasket groove  122 . It should be appreciated that the extra height guard  164 , relative to the gasket  160 , will interfere with the downward movement of the battery pack  155 . As a result, depressions  124  are provided to accept the guard  164 . There is no requirement the guard  164  contact any of the surfaces on the depressions. The depressions are provided for clearance. 
         [0043]    Referring to  FIG. 11 , as those skilled in the art will appreciate, after the abutment surfaces of the latch and battery pack engage, the battery pack  155  is held in the slot  122  but there is significant energy in the spring  114  and spring contacts  162 , which if released will cause the battery pack  155  to move upward in the slot  112 . In order to remove the battery pack  155  from the slot  112 , a person pushes the latch  118  causing the latch to rotate about the pivot  142  that in turn disengages the abutment surfaces. 
         [0044]    Although certain embodiments of the invention have been illustrated and described in considerable detail, it will be understood that this was only one example and the numerous changes in the details of the construction and arrangement may be made without departing from the spirit and scope of the invention.