Abstract:
An autonomous mechanical CPR device is disclosed having a CPR unit attached to a free-standing support assembly. In operation, a victim is placed in the support assembly such that the CPR unit can compress the victim&#39;s chest. The CPR device is preferably portable, and it provides the recommended depth of chest compression at the recommended rate.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application 61/895,159 entitled “Autonomous Mechanical CPR Device” filed Oct. 24, 2013. The entire contents of the provisional application mentioned above are hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to kinesitherapy and more specifically to provide cardio pulmonary resuscitation (CPR). 
       BACKGROUND OF THE INVENTION 
       [0003]    Cardio Pulmonary Resuscitation (CPR) is a well-known, first-aid treatment ideally performed on a victim suffering cardiac arrest. CPR is an external heart massage technique that manually preserves blood circulation through a victim&#39;s body in an attempt to maintain the body&#39;s organs, primarily the brain, until a normal heart rhythm, or blood flow, can be restored. 
         [0004]    In the treatment, a person&#39;s chest (i.e., sternum) is compressed. The compressions of the chest in turn cause compression of the heart forcing blood to circulate through the cardiovascular system. 
         [0005]    Performing manual CPR (i.e., CPR compressions given by a person) is strenuous, even using devices that provide a mechanical advantage. Proper CPR requires about 100, 5-cm-deep compressions of the chest per minute, each compression potentially requiring a force upwards of 550 N. Therefore, maintaining high-quality, manual CPR for an extended period of time, even more than several minutes, can be exhausting. Additionally, as close proximity of the CPR provider to victim is required for manual CPR, maintaining continuous manual CPR is compromised when the victim on whom the CPR is being performed is being moved, whether being carried on a backboard (e.g., through doorways, down halls or on stairs) or transported in a vehicle. 
         [0006]    Autonomous mechanical CPR devices, which are well known in the art, can overcome many of the issues associated with providing CPR for extended periods of time. These CPR devices can be associated with a victim and once started do not require human intervention, or even necessitate human proximity, and will continue CPR as long as their power source permits. 
         [0007]    Autonomous mechanical CPR devices generally comprise a support assembly having a CPR unit (i.e., a device capable of compressing a chest) defining a freestanding structure. The support assembly typically mounts to a back plate, which is positioned under a victim, with the support assembly extending over the victim. In other words, the support assembly and back plate define an opening in which the victim is placed. 
         [0008]    What is needed in the art are autonomous mechanical CPR devices that are easy to store and deploy, and are compatible with a broad spectrum of body types. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention is an autonomous mechanical CPR device. The device has a CPR unit attached to a free-standing support assembly. In operation, a victim is placed in the support assembly such that the CPR unit can compress the victim&#39;s chest. The CPR device is preferably portable, and it provides the recommended depth of chest compression at the recommended rate. 
         [0010]    As an optional feature, the CPR device may include the ability to adjust the support assembly to permit the CPR unit to be placed properly relative to a victim&#39;s chest. In addition, the CPR unit may contain programming to allow relevant components of the CPR unit to be positioned autonomously by the CPR unit relative to a victim&#39;s chest. 
         [0011]    These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings which illustrate by way of example the features of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a front view drawing of the CPR Device. 
           [0013]      FIG. 2  is a top view drawing of the CPR Device. 
           [0014]      FIG. 3  is a side view drawing of the CPR Device. 
           [0015]      FIG. 4  is a side view drawing of the backplate. 
           [0016]      FIG. 5  is a top view drawing of the backplate. 
           [0017]      FIG. 6  is a side view drawing of a latch assembly. 
           [0018]      FIG. 7  is a side view drawing of the latch handle, which is part of the latch assembly. 
           [0019]      FIG. 8  is a front view drawing of the latch assembly. 
           [0020]      FIG. 9  is a section drawing taken along line  9 - 9 , shown in  FIG. 1 . 
           [0021]      FIG. 10  is a section drawing taken along line  10 - 10 , shown in  FIG. 3 , with the outer surface removed and the backplate removed. 
           [0022]      FIG. 11  is a section drawing taken along line  10 - 10 , shown in  FIG. 3 , with the outer surface removed and the backplate partially inserted. 
           [0023]      FIG. 12  is a section drawing taken along line  10 - 10 , shown in  FIG. 3 , with the outer surface removed and the backplate fully inserted. 
           [0024]      FIG. 13  is a side view drawing with a section removed of the motor. 
           [0025]      FIG. 14  is a section view drawing of the motor depicted in  FIG. 13  taken alone line  14 - 14 , with the section removed in  FIG. 13  indicated. 
           [0026]      FIG. 15  is a side view drawing of the inner sleeve. 
           [0027]      FIG. 16  is a top view drawing of the inner sleeve. 
           [0028]      FIG. 17  is a side view drawing of the telescoping sleeve. 
           [0029]      FIG. 18  is a top view drawing of the telescoping sleeve. 
           [0030]      FIG. 19  is a side view drawing of the exterior sleeve. 
           [0031]      FIG. 20  is a top view drawing of the exterior sleeve. 
           [0032]      FIG. 21  is a drawing similar to  FIG. 13  except the inner sleeve is extended. 
           [0033]      FIG. 22  is a drawing similar to  FIGS. 13 and 21  except the inner sleeve has been sufficiently extended to cause the extension of telescoping sleeve. 
           [0034]      FIG. 23  is a side view drawing of the driveshaft with a section removed to show internal details. 
           [0035]      FIG. 24  is a side view drawing of the insert. 
           [0036]      FIG. 25  is a top view drawing of the insert. 
           [0037]      FIG. 26  is a side view drawing of a first mount. 
           [0038]      FIG. 27  is the top view drawing of the first mount. 
           [0039]      FIG. 28  is drawing of a user interface. 
           [0040]      FIG. 29  is a perspective side view drawing of a power system. 
           [0041]      FIG. 30  is a perspective view drawing of the power system slot in the compression system taken along line  30 - 30  with the power system removed. 
           [0042]      FIG. 31  is a cut away side view drawing of a first embodiment of a CRP pad ready to be mounted on the ram. 
           [0043]      FIG. 32  is a bottom view of the flange shown in  FIG. 31  taken along line  32 - 32 . 
           [0044]      FIG. 33  is a top view drawing of the CPR pad shown in  FIG. 31  taken along line  33 - 33 . 
           [0045]      FIG. 34  is a cut away perspective view drawing of the first embodiment of the CPR pad. 
           [0046]      FIG. 35  is a perspective view drawing of a second embodiment of a CPR pad. 
           [0047]      FIG. 36  is a cut-away perspective view drawing of the CPR pad shown in  FIG. 34 . 
           [0048]      FIG. 37  is a cut away, perspective view drawing of a third embodiment of a CPR pad connected to the ram. 
           [0049]      FIG. 38  is perspective view drawing of the CPR pad shown in  FIG. 36  connected to the ram. 
       
    
    
     DETAILED DESCRIPTION 
       [0050]    As shown in  FIG. 1  the CPR device, generally referred to by reference number  100  includes a support assembly (generally referred to by reference number  102 ), a compression system (generally referred to by reference number  200 ), a control system (generally referred to by reference number  350 ), and a power system (generally referred to by reference number  400 ). 
         [0051]    Support Assembly 
         [0052]    The support assembly  102  includes an arch  110  that connects to a backplate  112 . The arch  110  and backplate  112  cooperate to define an opening  106  suitable in cross-section to allow placement of a victim within the support assembly  102 . More specifically, the cross-section of the support assembly  102 , in the region under the lowest point of the compression system  200 , is sized based on the transverse cross-section of a human torso  113  in the thoracic region at the position of the heart (i.e., when the back is positioned on the back plate and the sternum is under the compression system). The actual size of the cross-section of the support assembly  102  is a matter of design choice; however, a suitable cross-section would allow the CPR device  100  to be used on a substantial portion of the population. 
         [0053]    The support assembly  102  is rigid. As used herein, “rigid” means a structure that is not flexible, but may be subject to minor temporary deflections, which may be perceptible or not, when loads are applied under normal operating conditions. 
         [0054]    As shown in  FIGS. 1-3 , the arch  110 , which is illustrated as generally symmetrical, has handles  114 ,  116 , one on each side. The handles  114 ,  116  allow a user to grasp the arch  110  to accomplish such actions as disconnecting the arch  110  from the backplate  112 , or placing the arch over a victim and connecting it to the backplate, which would be positioned under the victim. 
         [0055]    Referring to  FIGS. 4 and 5 , the backplate  112  preferably has a curvature generally consistent with that of a victim&#39;s back. To provide stability to the backplate or to the support assembly  102  when placed on a surface, a passive anti-roll system  122  may be incorporated. The illustrated passive anti-roll system  122  may be a cooperating pair of protrusions  124 ,  126  extending outwardly from the bottom  128  (the side opposite that in contact with the victim&#39;s back) of the backplate  112 . Preferably, the protrusions  124 ,  126  are sized such that when the backplate  112  is placed on a flat surface (not shown) both protrusions are simultaneously in contact with the surface. However, the protrusions  124 ,  126  maybe sized to work independently in corporation with a portion of the bottom  128 . 
         [0056]    The backplate  112  further includes tabs  142 ,  144  that extend outwardly from the ends of backplate. Extending through and outwardly from each tab is a latch pin  134 ,  136 . 
         [0057]    The arch  110  is connected to the backplate  112  by a latch system (generally referred to by reference number  140 ). A first portion of the latch system  140  is located in the arch  110  and a cooperating second portion is located in the backplate  112 . In the illustrative example, there are two latch systems  140 . 
         [0058]    Continuing with  FIGS. 6 ,  7  and  8 , the latch  600 , which is the first portion of the latch system  140 , includes a latch handle  602  and a latch portion  606  connected by a mid-section  604 . More specifically, the mid-section  604  defines a pair of cooperating bores  612 ,  614 . The latch handle  602  also defines a bore  618 . An axle  616  is passed through the bores  612 ,  614 ,  618  thereby rotationally connecting the mid-section  604  to the latch handle  602 . The latch portion  606  is ridgedly connected to the mid-section  604 . 
         [0059]    Extending from the latch handle  602  is a tab  620  that abuts a bearing surface  622  in the mid-section  604 . When the latch handle  602  is pushed such that the tab  620  interacts with the bearing surface  622 , the latch handle pivots about the axle  616  and the tab causes the mid-section  604  to rotate in the same direction, which in turn moves the latch portion  606 . It should be appreciated that since both the latch handle  602  and the mid-section  604  pivot about the axle  616 , and the two are not ridgedly connected, the latch portion  606  can be rotated about the axle independently of the latch handle. 
         [0060]    The latch portion  606  includes cooperating detents  630 ,  632 , a cavity  634  dimensioned to receive a tab  142 ,  144  located on the backplate  112 , and bearing surfaces  636 ,  638 . 
         [0061]    Referring to  FIG. 3 , the latch handle  602  is positioned on the arch  110 , one below each handle  114 ,  116 . The latch handle  602  is positioned relative to its respective handle  114 ,  116  such that the fingers of a hand can depress the latch handle inward (into the opening  106 ) to release the arch  110  from the backplate  112 . More specifically, a hand is placed on a handle  114 ,  116  such that the thumb is on the inside (the side within the opening  106 ) and the fingers are extending downward on the other side. The placement of the latch handle  602  should allow the finger tips to touch the latch handle such that fingertips can exert sufficient force to move the latch handle  602 . 
         [0062]    Continuing with  FIG. 9 , the latch portion  606  is located at the base of the arch  110 . The arch  110  defines openings  160 ,  162  for receiving the portion of the latch system located on the backplate  112 . 
         [0063]    The latch pins  134 ,  136  are the second portion of the latch system  140  and are located on the backplate  112 . In this illustrative case, the latch pins  134 ,  136  extend outwardly from both sides of the tabs  142 ,  144  and are generally parallel one to the other. 
         [0064]    As shown in  FIG. 9 , a latch pin  134 ,  136  enters the opening  160 ,  162  in the arch  110  and is secured under that latch portion  606 . The engagement of the latch portion  606  with a latch pin  134 ,  136  is illustrated in  FIGS. 10 ,  11 , and  12 . As shown in  FIG. 10 , the latch portion  606  is in its normal position without the backplate  112 . The latch portion  606  is biased in this position by a spring  626  (see  FIG. 6 ) acting on an abutment  628  projecting outwardly from the mid-section  604 . As illustrated in  FIGS. 1 ,  2  and  3 , an outside surface  628  of the latch portion  606  defines a portion of the outside surface of the arch  110 . 
         [0065]    Continuing with  FIG. 11 , the latch pin  134 ,  136  engages the latch portion  606  on a contact surface  650 . This engagement causes rotation of the latch portion  606  outside the arch  110 , clearing an entry way into a seat  652 ,  654 . As shown in  FIG. 12 , after the latch pin  134 ,  136  enters the seat  652 ,  654 , the latch portion  606 , which has detents  630 ,  632 , secures the latch pin. 
         [0066]    The entry from the opening  160 ,  162  to the seat  652 ,  654  may be flared and contoured. Flaring controls the precision needed for placing the latch pin  134 ,  136  within the opening  160 ,  162 . Contouring controls how the latch pin  134 ,  136  travels once within the opening  160 ,  162 . 
         [0067]    It should be appreciated placement of a latch pin  134 ,  136  into an opening  160 ,  162  will be a “blind” placement, as a user is placing the opening over a latch pin. As a result, the greater in area the opening  160 ,  162  is the easier it will be to attach the arch  110  to the backplate  112 . 
         [0068]    As shown in  FIG. 9  in this illustrative example, flaring is provided both longitudinally and laterally within the opening  160 ,  162 . Longitudinal flaring is provided by a first contoured surface  902 . Lateral flaring is provided by cooperating second and third contoured surfaces  904 ,  906 . These contoured surfaces define the flare by creating an opening that is larger than the opening that would have otherwise been defined if the surfaces of the seat  652 ,  654  where extended. 
         [0069]    The contouring guides the relevant latch pin  134 ,  136  within the relevant opening  160 ,  162  to the relevant seat  652 ,  654 . In this illustrative example, there is sufficient contouring such that as the ends of the latch pin interacts with contouring the tab  142 ,  144  are prevented from contacting any of the surfaces that define the opening and seat. The contoured surface  910 , which does not guide a pin end, is provided to avoid having the tab  142 ,  144  contact any surface due to the play permitted by the other contoured surfaces. After the latch pin is secured, the tab  142 ,  144  of the backplate  112  is in the cavity  634  and not touching the latch portion  606 . 
         [0070]    The contouring of the opening, the contact surfaces  636 ,  638  of the latch portion  606 , and the spring bias applied to the latch portion cooperate to determine the ease by which the latch pins  134 ,  136  will slide into the seat  652 ,  654 . It is desirable to make the force required to engage the latch pins  134 ,  136  relatively consistent. A relatively constant force can be achieved by maintaining, or minimizing the change in, the angle of attack of the latch pins  134 ,  136  on the bearing surface  636 ,  638 . In this case, the bearing surface  636 ,  638  is given an outward curvature to minimize the change in the angle of attach as the latch pins  134 ,  136  are inserted. 
         [0071]    It should be appreciated that since both the latch portion  606  and latch handle  602  pivot about the axle  616 , the latch portion, without displacing the latch handle, can be displaced by grasping a bottom edge  656 ,  658  of the latch portion. As a result, the latch  600  can be disengaged from the latch pin  134 ,  136 , permitting the backplate  112  to be disconnected from the arch  110 , by pulling outwardly on the bottom edge  655  of the latch portion  606 . More specifically, pulling on the bottom edge  655  causes the latch portion  606  to rotate about the axle  616 . Thus, if the latch handle  602  cannot be rotated inward, such as if the victim&#39;s body prevents it, the arch  110  can still be disconnected from the backplate  112 . 
         [0072]    This latch design permits either latch to be disengaged by pushing the latch handle  602  inward or grasping of the bottom edge  655  and pulling it outward, or one latch to be disengaged as describe above and the other latch to be disengaged by rotation of the arch  110  about the still connected latch pin  134 ,  136 , creating a multi-disengagement latch. A “multi-disengagement latch” as used herein means a latch that has more than one non-destructive mechanism by which it can be disengaged. More specifically, as the arch  110  is rotated about a latch pin  134 ,  136  the bottom surface of the backplate  112  impacts the bottom edge  655  of the latch forcing it outward causing it to disengage. Disengaging a latch by rotation offers the advantage of easy removal of the arch  110  from the backplate  112  by rotating arch about the victim instead of having to reach over the victim and pick the arch straight up over the victim. 
         [0073]    Compression System 
         [0074]    The compression system  200  provides the movement necessary for the CPR Device  100  to provide CPR to a victim. As shown in  FIG. 1 , the compressions system  200  is mounted to the arch  110 . The compression system  200  incorporates a drivetrain (generally referred to as  201 ) having a motor  210 , drive  209  and a ram  220 . In this illustrative example, drive  209  is a linear drive and more precisely a linear actuator of the ball screw type, due to its low friction characteristics. The drivetrain  201  is mounted to a housing  203 , which acts as a foundation. 
         [0075]    When the compression system  200  is secured in the arch  110 , the CPR pad  204  is positioned such that it will be above and generally centered on the sternum of a victim positioned within the opening  106 . As illustrated, the motor  210  is positioned above the arch  110  with the drive  209  and ram going through the bore  207 . 
         [0076]      FIG. 13  is a drawing of an illustrative motor. The illustrated motor  210  is an “out-runner,” but other motors could be used. In this style of motor, the rotor  214  rotates outside of the stator  212 . 
         [0077]    As shown in  FIG. 13A , the rotor  214  has a center hub connected by spokes to an outer ring. It is possible to give the spokes a wing shape (e.g., mean camber equal to or greater than 0, twist, and angle of attach), such that the rotor when rotating acts as a fan. 
         [0078]    In this illustrative case, the motor is a DC motor; thus, rotational direction of the rotor  214  is controlled by the polarity of the power supplied to the stator  212 . 
         [0079]    Referring to  FIGS. 22 and 23 , the drive  209  has a driveshaft  222  that connects to the motor&#39;s  210  rotor  214 . 
         [0080]    Continuing with  FIGS. 13 and 14 , the nut  230  rides on the thread portion  226  of the drive  209 . The nut  230  is rigidly secured by one or more connectors  232  to an inner sleeve  234  of the ram  220 . The connection system is a matter of design choice and may be permanent or allow for non-destructive disconnection. Some suitable connectors are pins, screws, or rivets. 
         [0081]    The inner sleeve  234  of the ram  220  has a distal end  205 . In this illustrative example, the distal end is define by an outer surface of a CPR pad  204 . Thus, as the nut  230  travels along the thread portion  226  of the driveshaft  222 , the distal end  205  moves. The distal end  205  completes one stroke by the nut  230  moving down the threaded portion  226  and then being retracted by moving up the threaded portion. 
         [0082]    Referring to  FIGS. 15 and 16 , the inner sleeve  234  has attached to and projecting outwardly therefrom cooperating rollers  238 . In this illustrative example, there are four rollers with one positioned at 0, 90, 180, and 270 degrees. 
         [0083]    Referring to  FIGS. 13 ,  17  and  18 , the inner sleeve  234  is positioned within a telescoping sleeve  240 . As shown in  FIGS. 17 and 18 , the telescoping sleeve  240  defines inner channels  242  on the inside. At least one roller  238  on the inner sleeve  234  is placed in the appropriate inner channels  242 . In this illustrative example, each roller  238  has an inner channel  242 . The rollers  238  should roll in an orientation that allows them to move along the inner channel  242 . 
         [0084]    Positioned within at least one channel  242  is a bottom stop  244  and within at least one channel, which may be the same channel, an upper stop  246 . The function of the stops is discussed below. 
         [0085]    The telescoping sleeve  240  of the ram  220  also has at least one outer channel  248 . The illustrated outer channels  248  are offset 45 degrees from the inner channels  242 . Similarly to the at least one inner channels  242 , there are outer upper stop(s)  257  and outer lower stop(s)  258 . 
         [0086]    Referring to  FIGS. 13 ,  19 , and  20 , the telescoping sleeve  240  is inserted into an outer sleeve  260 . As shown in  FIG. 19 , the outer sleeve  260  has at least one inwardly projecting tab  262 . The tab(s)  262  are inserted in respective outer channels  248  of the telescoping sleeve  240 . 
         [0087]    It should be appreciated by those skilled in the art, that the structure for the telescoping sleeve  240  could be repeated such that there is more than one telescoping sleeve. 
         [0088]    Any rotation of the inner sleeve  234  is not desirable. In the illustrated example, a torque transfer system from the nut  230  to the outer sleeve  260  is provided by the linkage system from the nut to the inner sleeve  234 , from the inner sleeve to the telescoping sleeve  240 , and from the telescoping sleeve to the outer sleeve  256 . More precisely, the connectors  232  and the edges of the inner and outer channels  264 ,  266  interacting respectively with the sides of the rollers  236  and the tabs  246 . 
         [0089]      FIGS. 13 ,  21 , and  22  depicts the interaction of the various sleeves—inner sleeve  234 , telescoping sleeve  240 , and outer sleeve  260 —of the ram  220 . In  FIG. 13 , the inner sleeve  234  is not extended. In  FIG. 21 , the inner sleeve  234  has been extended but not sufficiently enough to cause a roller  238  on the inner sleeve  234  to impact a bottom stop  244  on the telescoping sleeve  240 . As a result, the telescoping sleeve  240  remains in position due to the friction created by tabs  262  on the outer sleeve  260  within outer channel  248 . In  FIG. 21 , the inner sleeve  234  has been extended sufficiently to cause a roller  238  to impact a bottom stop  244  and providing sufficient energy to overcome the friction created by the tabs  262  thereby extending the telescoping sleeve  240 . This procedure when reversed (upper stop  246  instead of bottom stop  244 ) will cause the telescoping sleeve  240  to retract. 
         [0090]    It should be appreciated that the telescoping sleeve  240  permits the nut  230  to act as a lower bearing for the driveshaft  222 . As a result, an intermediate bearing between an upper bearing and a lower bearing is avoided. For the nut  230  to be an effective lower bearing the overlap of the telescoping sleeve  240  relative to the inner sleeve  234  and the outer sleeve  260  must be sufficiently ridged. An overlap of 4 to 1 (length remaining with a sleeve to extension) is suitable. 
         [0091]    It is desirable that the diameter of the telescoping sleeve  240  not exceed the diameter of the CPR pad  204 , such that the telescoping sleeve is concealed above the CPR pad. It, also, should be appreciated that while the various sleeves have been described is cylindrical terms, this is not a requirement of the invention, and the use of cylindrical terms herein should not be considered limiting unless expressly stated as limiting. 
         [0092]    Continuing with  FIG. 23 , the driveshaft  222  has an orifice  270  leading to an oil sump  272 . Above the bottom of the oil sump  272 , is a passage  274  to permit oil to exit the oil sump and lubricate the thread portion  226 . The passage  274  is placed below the motor but above the upper most position of the nut  230 . Oil is put into the oil sump  272  through the orifice  270 . The driveshaft  222  also is lightened by a centerline bore  276 . 
         [0093]    In this illustrative example, the compression system  200  is removable from the arch  110 . More precisely, at least a portion of the housing  203  of the compression system  200  is inserted in the arch  110  in a through bore defined by the arch and held therein by a first mount (generally referred to by reference number  280 ). As shown in  FIGS. 24 ,  25 ,  26 , and  27 , the first mount is of the quick-disconnect style, a quarter-turn type, that includes an insert  282 ,  FIGS. 24 and 25 , integrated into the compression system  200  that engages a lock  284 ,  FIGS. 26 and 27 , that is integrated into the arch  110 . 
         [0094]    Continuing with  FIGS. 24 and 25 , the insert  282  defines a thru-bore  286  through which the ram  220  is positioned. More precisely, the outer sleeve  256  of the ram  220  is placed in the thru-bore such that the motor is on one side of the insert  282  and the CPR pad  204  is on the other. The outer sleeve  256  of the ram  220  is secured to the insert  282 . In this illustrative case, it is permanently connected (i.e., destructive disconnection), but it could be by temporary fasteners, such as screws, which would allow non-destructive removal. 
         [0095]    Positioned on the outer surface of the insert  282  is a pair of keys  288 . The keys  288  are generally triangular having a base  290  and apex  292 , which points in the direction of the CPR pad  204 . 
         [0096]    The insert also includes a pair of bosses  294  that provide the connection between the insert  282  and a housing  203  (see  FIG. 1 ). 
         [0097]    Continuing with  FIGS. 26 and 27 , the insert  282  is dimensioned to slide into a bore  296  defined by the lock  284 . On the surface of the bore  296 , is a pair of keepers  298 . The keepers  298  are generally triangular with the apex pointing at the opening in the bore  296  through which the insert  282  will be inserted. The keepers  298  are positioned such that they are not touching; thus defining a number of gaps equal to the number of keepers. Each gap should be only slightly larger (i.e., just wide enough to let the key slip between the keepers) than a key  288 , as it is desirable to have a key impact a keeper  298  upon insertion of the insert  282  into the housing  203 . 
         [0098]    The base  300  of the keepers  298  define a notch  304  dimensioned to accept the base  290  of the key  288 . The base  290  on either side of the notch  304  is curved toward the apex, such that the base vertices  308 ,  310  are “below” the notch entrance. 
         [0099]    At the base of the thru-bore  286  is a flange  315  that interacts with a bias plate  312 . More specifically, the bias plate is secured by a pin  317  running through each at least on spring  314 . The pin  317  passes through the flange  315  and connects to the bias plate  312 , which effectively traps the at least one spring  314  between the top of the pin and the flange. 
         [0100]    The bias plate  312  has an inner surface  316  within the thru-bore  286 , which is dimensioned to be impacted by the insert  282  when it is inserted. Prior to the insert  282  impacting the inner surface  316 , the at least one spring  314  is in compression causing the bias plate  312  to be held firmly in place against the bottom of the flange  315  on the lock  284 . When impacted by the inner surface  316 , the pin  317  by movement of the bias plate, to which the pin is connected, acts to put the at least one spring  314  in further compression. 
         [0101]    Upon insertion of the insert  282  into the lock  284 , the keys  288  will impact a keeper  298 ; assuming placement does not put them in a gap. Upon impacting the keeper  298 , the insert will rotate (in this design rotation can be either clockwise or counter-clockwise) as the apex of the key slides down an edge of a keeper. As the apex of the key  288  passes a base vertex of a keeper  298 , insertion of and rotation of the insert continues until the base  290  of the key passes a base vertex of the keeper; thus causing the further compression of the at least one spring  314  to be released thereby self-locking the compression system  200  to the arch  110 . 
         [0102]    At some point during the insertion of the insert  282  before the base  290  of the key  288  passes a base vertex of the keeper  298 , the bottom edge of the insert will impact the bias plate  312  causing the at least one spring  314  to extend. At the point where the key  288  passes a base vertex  308 ,  310 , and with continued rotation of the insert  282 , the bias plate  312  will begin to force the key to maintain contact with the keeper  298  until such point that the upper base  290  of the key is securely within the notch  304 . To disengage, the procedure is performed in reverse beginning with pushing the insert  282  toward the bias plate  312  to cause the key  288  to disengage from the keeper  298 . 
         [0103]    Referring to  FIG. 2 , insertion of the compression system  200  into the arch  110  may be accomplished using second handles  320  positioned on the housing  203 . 
         [0104]    It should be appreciated that in operation compressive force exerted by the downward movement of the CPR pad  204  will cause the support assembly  102  to flex. Referring to  FIG. 1 , the opening  106  will be distended by the movement of the top portion of the arch  110  away from the backplate  112 . As a result, the support assembly  102  should have sufficient structural integrity to limit this distention, for example to no more than about ⅜ ths  of an inch during a CPR stroke. 
         [0105]    Control System 
         [0106]    Continuing with  FIG. 28 , a user interacts with the compression system  200  using a control system  350 . The control system  350  is a micro-processor having programming running thereon interacted with by a user through a control panel  352 . 
         [0107]    The illustrative control panel  352  includes control over the functions of on/off switch  354 , CPR pad adjustment control  356 , CPR start switch  358 , CPR stop switch  360 , and CPR pause  362 . Also, control panel  352  includes an on/off control over an audio system  372 , and a battery status indicator  366 . 
         [0108]    To operate the compression system  200 , a user turns ON the control system  350  by changing the status of the on/off switch  354 . When the control system  350  is turned ON, the control system may locate the CPR pad  204  in a known position or obtain the position, referred to as an initial position. The initial position permits the control system  350  to achieve the desired depth of compression. 
         [0109]    At this time, a system self-test might also occur, or the results of a self-test conducted while in the OFF state might be reported. In the case of a self-test occurring upon startup, or a previously conducted self-test, such as one conducted in the OFF state, the results are indicated using perceptible, visual, tactile, or audible, output. In this illustrative example, a visual output  368  (e.g. light) is used, which illuminates if the compression system is not functioning properly. The system could also function in reverse with the visual output illuminating if the compression system was functioning properly. In addition, there could be a distinct illumination for either operational condition. 
         [0110]    The compression system  200  next places the distal end  205  of the CPR pad  204  into a therapeutic position. The therapeutic position is defined as a start position from which CPR can be effectively delivered (i.e., sufficiently compress the sternum). The spatial difference between the initial position and the start position is the offset. 
         [0111]    The start position places the distal end  205  into firm contact with the victim&#39;s chest. One method to accomplish this placement is to direct the motor  210  to place the distal end  205  of the CPR pad  204  into contact with the chest such that a pressure between about 11 to 13 kg, with about 12.25 kg being a reasonable amount, is exerted on the chest. Then, put the drivetrain  201  in neutral permitting that distal end  205  to freely change position. In the neutral position, the compressed chest pushes back against the distal end  205  causing the distal end to be retracted (i.e., displaced toward the initial position) until the chest and compression system  220  are in equilibrium. The point at which the distal end  205  comes to rest is the start position. It should be appreciated that to assure that the start position is in firm contact of the distal end  205  with the chest (compress the skin but not the sternum), a minor displacement in the equilibrium position, thus the start position, toward the chest could be made, which would generate minor, but insignificant, pressure on the chest. 
         [0112]    The control system  350  may automatically detect the start position employing a proportional integral controller (PI controller). In an illustrative example, the PI controller monitors the speed of decent of the CPR pad  204  from the initial position toward the start position. During decent, an initial voltage applied to the motor  210  is a fraction of that needed to administer CPR. While a matter of design choice, the initial voltage must be less than a voltage need to perform CPR, a maximum voltage of around 50% is acceptable, but greater than zero, voltage around 10-17% is a practical minimum. When the CPR pad  204  initially contacts a chest, the resistance of the chest will cause the speed of decent of the CPR pad  204  to slow, or stop if at maximum voltage. In the event the maximum voltage is not being applied to the motor  210  at initial contact, the voltage applied to the motor is increased (i.e., to a voltage proportional to the error in the PI) in an attempt to cause the CPR pad  204  decent to continue. When the maximum voltage is reached and the decent does not continue, the CPR pad  204  is considered in the start position. 
         [0000]    It should be appreciated that a similar procedure could be used to position the CPR pad  204  is any position where the position is determined by resistance, such as the home position. 
         [0113]    The CPR pad adjustment controls  356  permit the CPR pad  204  (see  FIG. 13 ), to adjusted both toward and away from a victim&#39;s chest, to manually adjust the start position. 
         [0114]    Once the CPR pad  204  is in the start position, CPR compressions can begin. CPR compressions are initiated by a CPR start switch  358 . CPR compressions are terminated by a CPR stop switch  360 . When the CPR stop switch  360  is depressed, the CPR pad  204  is repositioned to a stored position, which could be the initial position. 
         [0115]    CPR compressions can also be paused by changing the status of a CPR pause button  364 . When CPR compressions are paused, the CPR pad  204  remains in a position suitable to continue CPR compressions when the pause is terminated. More specifically, the CPR pad could be somewhere in the current CPR stoke, or automatically repositioned back to the current start position. It could also be possible to automatically relocate the CPR pad back to some other position as long as the current start position is remember such that when the pause is released the CPR pad automatically returns to suitable position to resume compressions. 
         [0116]    The control system  350  may permit control over the depth of the compressions. For example, as the offset (the distance between the initial position and the start position) is increased the depth of compression may decrease. The recommended compression depth is 5 cm, but there is an inverse relationship between the offset and the victim size. More precisely, as the offset increases the victim is getting smaller (i.e., the victim&#39;s cross-section in the thoracic region is decreasing). As a result, the standard compressive depth of 5 cm could be too great. 
         [0117]    There are numerous ways in variable compression depth could be implemented. It could be automatic, such that extension determines compression depth. Alternatively, there could be user adjustment, such as through the control panel  352 . The system could also be user activated or deactivated, for example by a button (not shown) on the control panel  352 . 
         [0118]    A battery meter  370  is also provided. The battery meter  370  provides a visual indication of the charge status of the battery. 
         [0119]    Programming in the CPR control system  350 , may include audio assistance in using the device. The on/off switch  372  controls output of the audio assistance through a speaker (not shown). 
         [0120]    The CPR control system  350  may also include a visual status indicator  368 , in this illustrative case a light, to indicate the operational status, functioning and/or malfunctioning, of the device. A speaker if available could also be used (e.g., a chirp in the event of a malfunction). The status could be obtained from self-tests, either performed automatically when the CPR unit is OFF, upon startup, or upon user direction. 
         [0121]    Power System 
         [0122]    Referring to  FIGS. 29 and 30 , the compression system  200  and control system  350  are powered by a power system power system  400 , as illustrated a battery pack that which inserts into a power system slot  402 . The power system  400  has a certain number of cells, individual or unified multi-cell, based on the capacity needed, which cells may be rechargeable. 
         [0123]    Continuing with  FIG. 29 , the power system  400  has an outer case  404  that is dimensioned to fit into the power system slot  402 . As shown in  FIG. 1 , only a portion of the outer case  404  fits within the power system slot  402  with the balance creating a gripping portion. 
         [0124]    The power system  400  further has one-half of an electrical connector  406 , comprised of a series of individual connectors  408 , located on the bottom. The electrical connector  406  is symmetrical about the centerline lines of the power system  400 . In addition, the power system  400  has tabs  410  (one on each side), symmetrically located about a centerline, which is shared with the electrical connector  406 . 
         [0125]    As shown in  FIG. 30 , latches  412 , which are spring biased, generally simultaneously engage tabs  410  to secure the power system  400  in the power system slot  402 . The power system slot  402  also has complementary connector  414  to the electrical connector  406  on the power system  400 . A spring  416  is also provided. By insertion of the power system  400  in the power system slot  402 , the spring  416  is compressed permitting the spring to assist in battery removal when the latches  412  are released. 
         [0126]    The symmetry of the outer case  404 , the latches  412 , the electrical connector  406  and the complementary connector  414  permits the power system  400  to be inserted in the power system slot  402  in more than one orientation, two in this illustrative example. 
         [0127]    Optionally, power can be provided by a line voltage source. 
         [0128]    Accessories 
         [0129]    As discussed above, the CPR Device  100  may have a CPR pad  204 . Where it is intended that the outer surface of the CPR pad  204  touch a victim, the CPR pad should be replaceable. Temporary attachment could be by a quick-disconnect second mount such as snap-on, magnets, hoop and loop fastener, etc. 
         [0130]    Generally, the material for the CPR pad  204  is a matter of design choice but should be generally non-compressible, or minimally compressible, so it does not interfere with the compressing action of the device and the outer surface should be of a material that provides some friction when in contact with skin or clothing to aid in maintaining the position of the ram  220  on the sternum (e.g., avoid sliding). 
         [0131]    A first embodiment of CPR pad  204  is shown in  FIGS. 31 ,  32 ,  33 , and  34 , generally referred to by reference number  204 - 1 . The CPR pad  204 - 1  includes a frame  508  having a pad  502  mounted thereon. 
         [0132]    The CPR pad  204  is made from a soft material to allow the pad  502  to adopt a contour consistent with the sternum. It should be noted that the pad  502  extends to the edges to the frame  508  preventing the edges of the frame from contacting the sternum. 
         [0133]    The frame  508  is rigid and defines an alignment guide  512  and a depression into which a magnet  504  is mounted. The magnet  504  is secured in the frame  508  by washer  518 . 
         [0134]    The alignment guide  512  on the CPR pad  204 - 1  interacts with an alignment channel  510  in a flange  516 , which is attached to the inner sleeve  234  of the ram  220 . The action of placing the CPR pad  204 - 1  on the flange  516  causes cooperating angles located on the CPR pad and flange  522 ,  524 , respectively to interact forcing the CPR pad to self-center on the flange, which causes the alignment guide to locate in the alignment channel. In this illustrative example, the flange  516  is made of ferrous metal so it interacts with the magnet  504  to create a magnetic attachment. 
         [0135]    A second embodiment of CPR pad  204  is shown in  FIGS. 35 and 36 , generally referred to by reference number  204 - 2 . The CPR pad  204 - 2  is made from a generally firm material that can be stretched. 
         [0136]    The CPR pad  204 - 2  includes a body  530  that defines a retaining recess  532 . It further includes multiple air pockets  534 , each air pocket being of a cup shape and having a sealing surface  536 . 
         [0137]    In use, the CPR pad  204 - 2  is stretched over a flange (not shown) connected to the inner sleeve  234  of the ram  220 . When placed on the flange, the sealing surfaces interact with a surface on the flange such that an air pocket is defined. When the CPR-pad  204 - 2  is compressed against the sternum, air will slowly escape from the air pocket; thereby, giving some degree of conformity of the CPR pad to the sternum. It should be appreciated that when the inner sleeve  234  of the ram  220  is retracting, the air pockets will refill with air as the CPR pad  204 - 2  returns to its normal configuration. 
         [0138]    A third embodiment of CPR pad  204  is shown in  FIGS. 37 and 38 , generally referred to by reference number  204 - 3 . The CPR pad  204 - 3  is similar to second embodiment of the CPR pad  204 - 2 . Except in this embodiment, the pad  560  defines voids  562 . 
         [0139]    While the invention has been described above by reference to various embodiments, it will be understood that many changes and modification can be made without departing from the scope of the invention. In addition, the control system  350  contains a micro-processor with suitable components, such as memory, to retain and execute programming to carry out the above functions. The programming needed to accomplish the above functions is well known in the art, and the programming can be written based on the above provide functional capabilities. It is therefore intended that the foregoing detailed description be understood as an illustration of the presently preferred embodiments of the invention, and not as a definition of the invention. It is only the following claims, including equivalents, which are intended to define the scope of this invention.