Abstract:
The acceleration recorder provides a three dimensional mechanical record of the acceleration sustained in a collision or impact. The recorder converts impact into a rotational movement of an internal weight about three orthoganl axes. Mechanical indicators remain at the limits of the weight rotations.

Description:
FIELD OF THE INVENTION  
         [0001]    The acceleration recorder of this invention is related to the field of collision dynamics and in particular to a recordation mechanism capable of detecting the magnitude of acceleration, in all three axes of a an orthogonal Cartesian coordinate system X, Y, and Z, that an object has been exposed to during an impact or collision.  
         BACKGROUND OF THE INVENTION  
         [0002]    Millions, if not billions, of dollars are paid out each year, in the United States alone, as a result of injuries due to accidents, crashes or collisions. A significant amount of this is due to fraudulent claims based on minor accidents or, in some instances, no accident at all. Conversely, many legitimate claims go unpaid because the injured are unable to verify the extent of the impact and their injuries. In view of this problem, attorneys typically retain professional engineers to perform forensic analyses using available techniques to determine the accelerations of a crash or collision. Thus, it is recognized that there is a need to be able to determine the accelerations a person, vehicle or other object has been subjected to in a collision. By having a means for recording and determining the severity of a collision, the evaluation of the resulting injuries could be more accurate and expedient.  
           [0003]    At present, most serious accidents involving bodily injuries are subjected to extensive forensic analysis. By examining the physical evidence, such as skid marks, weight and geometry of the colliding vehicles, points of impact and rest, and the resultant damage of a collision, the approximate forces of an impact may be calculated. The calculated forces can then be utilized to calculate the approximate average accelerations the occupants experienced in the collision. The three-dimensional acceleration vector determines, to a great extent, the injuries to the occupants; however, these analyses are typically only in two dimensions.  
           [0004]    The National Highways and Transportation Safety Administration (NHTSA) of the U. S. Department of Transportation has conducted numerous barrier tests to determine the stiffness properties of various types of vehicles. The weight of the vehicle, the speed at impact and the exact amount of resultant damage are recorded. Utilizing Newton&#39;s Law of Motion and Hooke&#39;s Spring Law, the impact forces and resultant stiffness properties are calculated. In future investigations of similar vehicles, the somewhat linear nature of vehicle stiffness allows investigators to approximate impact forces based on varying amounts of collision damage. These calculated forces could then be used in occupant acceleration calculations; however, the results only proximate the actual accelerations endured by the occupants.  
           [0005]    Calculating head accelerations during athletic event impacts is even more challenging. Numerous sports involve the potential for significant head impacts during play; most notably among these sports is football. Repetitive head impacts involving high accelerations have been medically shown to cause permanent brain injury and death; however, no current method exists to determine the magnitude of each impact. In fact, unconsciousness is often used to differentiate between an acceptable and unacceptable impact. Unfortunately, the levels of force required to render an individual unconscious is often significantly higher than the forces required to injure the brain.  
           [0006]    Now, there is no generally accepted small, light weight and inexpensive instrumentation that requires no batteries or external power and can be mounted on any vehicle or athletic protective gear, such as a helmet, to record the acceleration vector experienced by the participants of a collision or impact.  
           [0007]    This invention is directed to providing an instrument that could be included as standard safety equipment on every vehicle and helmet.  
         DESCRIPTION OF THE PRIOR ART  
         [0008]    Impact measuring devices are old in the art. For example, U.S. Pat. No. 5,551,279 describes a mechanical impact gauge for determining cumulative impact energy along a single axis using fixed bendable members within a chamber on either side of a freely movable object. Upon impact, the inertia of the movable object will cause the object to bend the fixed members. The amount of the bend can be used to calculate the force of impact.  
           [0009]    When the device is aligned with the vector of the impact, the information derived is relatively accurate; however, if the impact vector is at an angle to the axis of the device, only the longitudinal portion of the vector is recorded and the gauge can become very inaccurate.  
           [0010]    Of course, the “black boxes” carried by some commercial aircraft and in the airplanes of all commercial air carriers give detailed information about an accident. These devices are relatively large, very expensive and most have a continuous power source. Such sophisticated instrumentation, and it&#39;s cost, would place an undue burden on the price of individually owned vehicles and would be impossible to mount on a helmet.  
         SUMMARY OF THE INVENTION  
         [0011]    Any moving object may be equipped with one or more acceleration recorders of this invention, such as boats, cars, trucks, buses, airplanes, motorcycles, or helmets. During a collision, the acceleration recorder gives empirical data concerning the vectored acceleration of the object to which the recorder is attached. The data can be used to reconstruct the direction and magnitude of any collision. When two or more recorders are used in conjunction rotational accelerations can also be derived.  
           [0012]    Accordingly, it is an objective of the instant invention to provide an acceleration recorder that is inexpensive, small, lightweight and easy to permanently or removably mount on any vehicle or helmet. It is also an objective of this invention to provide an acceleration recorder that records acceleration in three orthogonal axes to provide a vector of the acceleration involved in a collision or impact.  
           [0013]    It is a further objective of the instant invention to provide an acceleration recorder that may be tamper-proof or user inaccessible.  
           [0014]    Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.  
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0015]    [0015]FIG. 1 is a perspective of the acceleration recorder of this invention;  
         [0016]    [0016]FIG. 2 is an exploded, perspective view of the base and tamper-proof shield;  
         [0017]    [0017]FIG. 3 is an exploded, perspective view of the acceleration recorder;  
         [0018]    [0018]FIG. 4 is a perspective of the Z-axis resolver and the cruciform casing;  
         [0019]    [0019]FIG. 5 is a perspective of the Y-axis resolvers and the inner orbit ring; and  
         [0020]    [0020]FIG. 6 is a perspective of the X-axis resolvers and the outer orbit ring. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    For the purposes of this disclosure, the acceleration recorder will be described as mounted on a base that is parallel with the ground and the Z-axis resolver mounted vertically there from. While each axis has been labeled for clarity, it is understood that the labels merely specify any three orthogonal axes in a three dimensional coordinate system. For simplicity of description, like parts have the same reference number where possible.  
         [0022]    Of course, during use, the acceleration recorder will be subject to its orientation relative to the vehicle, helmet or test bed upon which it is mounted. As part of the forensic analyses, the orientation of the acceleration recorder during the event must be determined for accurate reconstruction. The acceleration recorder  10 , shown in FIG. 1 is mounted on a base  11 . The base  11  is mounted on a vehicle or athletic protective gear, such as a helmet. Depending on the circumstances of use, the base may be mounted using a double-faced adhesive  12 , shown in FIG. 2.  
         [0023]    Where it is desired to make the device tamper-proof or to determine if the recorder has been tampered with, the base may be permanently attached to the vehicle, as by bolts, welding or such, not shown. The base  11  has a peripheral wall  13 , shown in FIG. 2, which may be permanently fixed to a protective covering  14 . The protective covering  14  closely fits about the wall  13  and prevents foreign objects from fouling the moving parts of the recorder  10  and is designed to withstand a greater impact than the accelerations the recorder has the capability of measuring. In some instances, the protective covering may be made of transparent acrylic. The protective covering may also be removably mounted on the base, in some applications.  
         [0024]    In FIGS. 1, 4,  5  and  6 , the acceleration recorder  10  has a Z-axis resolver  15 , two Y-axis resolvers  16  and two X-axis resolvers  17 . Each of these resolvers simultaneously and permanently records the maximum rotational displacement of a weight  18  relative to base  11  during impact. The rotation about three orthogonal axes is recorded so that a three dimensional vector of acceleration can be deduced.  
         [0025]    In FIGS. 2, 3 and  4 , the base  11  has a circular bearing journal  19  that receives a spindle  20  of the Z-axis resolver  15 . The spindle  20  extends upwardly from the bearing journal through a cruciform casing  21 . A collar  22  is formed on the spindle  20  for vertical support of the cruciform casing  21 . The ends of spindle  20  have bearing surfaces  23  and  24 . Bearing surface  23  is connected in bearing journal  19  and bearing surface  24  is connected to a journal  25  in the center of a disk  26 . The rotational and translational position of disk  26  is fixed relative to base  11 . The cruciform casing  21  rotatably rests on spindle  20  between the journal  25  and the collar  22 . The cruciform casing rotates about an imaginary center point  27  and serves to establish the perpendicular relationship between the Y and Z-axes of the recorder  10 .  
         [0026]    The disk  26  also has an eccentric aperture  28 . One end of a coil spring  29  is connected to the lower surface of the disk  26  in the eccentric aperture  28 . The spring extends downwardly from the disk and the coils  30  freely wrap around the journal  25  and the cruciform casing  21  ending in a hook shaped attachment  31  about a horizontal arm of the cruciform casing. The spring  29  is connected to the cruciform casing  21  so that rotational movement of the cruciform casing relative to the disk  26  is resisted by the spring. The force produced by spring  29  is directly proportionate to the angular displacement of cruciform casing  21 .  
         [0027]    When the object upon which the recorder  10  is mounted experiences a sudden change in position or velocity, the base  11  experiences the same change, resulting in rotation and translation of the disk  26  from its original position. Due to inertial resistance to a change in position or velocity, the weight  18  remains stationary when the base moves. This results in a rotation of cruciform casing  21 . The coil spring  29  provides a reactive force on the cruciform casing in response. When the limit of rotational and translational acceleration is reached, the spring returns the cruciform casing to its neutral position relative to base  11 .  
         [0028]    The disk  26  has angular calibrations  32  on the upper surface about a central aperture  33 . The calibrations  32  indicate the angular displacement of the cruciform casing  21  relative to the disk  26  during a collision. The calibrations may serve to directly record the rotational displacement of the Y-axis about the Z-axis or they may be used as a basis of calculations to determine the acceleration necessary to cause the indicated angular movement.  
         [0029]    An elongated indicator  34  has one end rotatably journaled in the central aperture  33  of the upper surface of the disk  26 . The indicator has an arm  35  that extends radially outward from the end journaled in the central aperture parallel to the upper surface of the disk, over the calibrations  32 , beyond the circumferential edge of the disk, and loops back below and parallel to the lower surface of the disk. The middle portion  36  of the indicator is disposed parallel to the journal  25  and ends in a curved portion  37  which is fitted around and coaxial to the cruciform casing  21  below the horizontal arms. As the cruciform casing rotates relative to disk  26 , the indicator  34  is pushed by the horizontal arms of the cruciform casing causing the arm  35  to rotate over calibrations  32 . The horizontal arms of the cruciform casing have flanges  38 . The flanges  38  serve as the retainer for the curved portion  37  of the indicators  34  in the Y-axis resolvers  16 , shown in FIG. 5.  
         [0030]    After the spring  29  returns the cruciform casing  21  to its neutral position, the indicator  34  remains at the farthest extent of rotation during impact. The magnitude of rotation of indicator  34  is determined by comparing arm  35  relative to calibrations  32  before and after impact. The indicator  34  maintains position through the tension in the loop of arm  35 . This tension is insignificant compared to the inertial forces of the cruciform casing  21  and attached hardware; however, the tension is enough to retain the indicator arm  35  in its original position or the position where it comes to rest as a result of an impact.  
         [0031]    In FIGS. 3, 4 and  5 , the Y-axis resolvers  16  are mounted at 180 degrees angle from each other on the horizontal arms of cruciform casing  21 . The cruciform casing has two bearing journals  39 ; each receives a spindle  40 . The two spindles  40  extend radially outward from the bearing journals  39  through bearing journals  41  in an inner orbit ring  42 . The ends of each spindle  40  have bearing surfaces  43  and  44 . Bearing surface  43  is connected in journal  39  and bearing surface  44  is connected in journal  25  in the center of disk  26 . The positions of disks  26  are fixed relative to cruciform casing  21 . The ring  42  rotatably rests on spindles  40  between the cruciform casing  21  and journals  25 . The ring  42  rotates about center point  27  and serves to establish the perpendicular relationship between the X and Y-axes of the recorder  10 . The calibrations  32  on disks  26  of the Y-axis resolvers indicate the angular displacement of ring  42  relative to the cruciform casing  21  during a collision.  
         [0032]    Coil springs  29  of the Y-axis resolvers  16  are connected to the ring  42  so that rotational movement of the ring relative to the cruciform casing  21  is resisted by the springs. The force produced by the springs is directly proportionate to the angular displacement of ring  42  relative to cruciform casing  21 . The springs provide the reactive force on the ring  42  in response to a change in the position or velocity of the cruciform casing  21 . When the limit of rotational and translational acceleration is reached, the springs return the ring  42  to its neutral position relative to cruciform casing  21 .  
         [0033]    In FIGS. 3, 5 and  6 , the X-axis resolvers  17  are mounted at 180 degrees angle from each other on the ring  42 . The ring  42  has bearing journals  45  that receive spindles  46 . The spindles  46  extend radially outward from the bearing journals  45  through bearing journals  47  in an outer orbit ring  48 . The ends of spindles  46  have bearing surfaces  49  and  50 . Bearing surface  49  is connected in journal  45  and bearing surface  50  is connected in journal  25  in the center of disk  26 . The positions of disks  26  are fixed relative to ring  42 . The ring  48  rotatably rests on spindles  46  between the ring  42  and journals  25  and in a greater orbit than ring  42 . The ring  48  carries weight  18  which may be made of lead. The weight  18  provides the inertial force relative to the base to initiate rotation about one or more of the three axes. The ring  48  rotates about a center point  27  and serves to establish the angular relationship between weight  18  and the X-axis of the recorder  10 . The calibrations  32  on disks  26  of the X-axis resolvers indicate the angular displacement of ring  48  relative to the ring  42  during a collision.  
         [0034]    Coil springs  29  of the X-axis resolvers are connected to the ring  48  so that rotational movement of ring  48  relative to ring  42  is resisted by the coil springs. The force produce by springs is directly proportionate to the angular displacement of ring  48  relative to ring  42 . The springs provide the reactive force on the ring  48  in response to a change in the position or velocity of the ring  42 . When the limit of rotational and translational acceleration is reached, the springs return the ring  48  to its neutral position relative to ring  42 .  
         [0035]    In a sudden collision, when a vehicle or helmet abruptly changes location, the attached base  11  and point  27  will translate and rotate exactly the same as the vehicle or helmet. Newton&#39;s Law of Motion states, “a mass at rest or constant velocity stays at rest or constant velocity until acted on by an outside force.” Therefore, the weight, which is free to move in all three directions, stays at rest or continues on its current trajectory. This results in an angular rotation of the weight about one or more of the three axes. The increasing rotations create increasing torsional forces from the coil springs and a simultaneous movement of the indicators about their respective disks. Eventually, the resultant combined force created by the springs becomes equal to the force required to accelerate the weight to the new neutral position and relative speed of base  11 . When the weight achieves the new neutral position and speed of base  11 , the spring tension unloads and the system reaches equilibrium. After the weight is returned to it&#39;s neutral position, the indicators will register the three rotational limits achieved during the collision.  
         [0036]    It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of what is shown and described in the specification and drawings.