Patent Publication Number: US-2005115574-A1

Title: Device for supporting the cervical vertebral column

Description:
The present invention relates to a device for supporting the cervical vertebral column according to the generic term of patent claim  1 .  
      Such a device follows the publication WO/PCT/EP 00/09759. It essentially comprises an assembly of pressurized cushions with at least two front cushions, which face each other in relation to the neck of the user. One the one side these two front cushions rest against the shoulder of a user and on the other side they support the undersides of the lateral lower jaw area of the user. Moreover, the said device has at least one cushion that is positioned in the rear section of the device that rests against the shoulder of the user on one side and supports the occipital squama of the user on the other side. These three cushions exert a pressure in their effective direction for supporting the head in a vertical direction. A control and regulation unit is provided which can selectively raise or lower the pressure in the pressurized cushions. Depending on the tilt of the head and the g-force components measured, this control and regulation unit can build up various countering forces in the effective direction.  
      A problem of a device of this kind for supporting the vertebral column is that the two front pressurized cushions supporting the undersides of the lateral lower jaw area make it difficult to turn the head even in a zero pressure state when the head is moved toward the front.  
      In addition, there is the possibility that when the head is tilted toward the front under stronger use of force, the chin of the user may slip through the front areas of both the front pressurized cushions such that the force-compensating function is no longer guaranteed and it is additionally not possible to carry out sideward movements any more.  
      A further problem of the said invention is the fact that the chin strap of the user&#39;s helmet can impair the function of the front cushions considerably. However, a helmet is indispensable.  
      The task of the present invention is, therefore, to create a device for supporting the vertebral column that allows for freedom of head movement.  
      This task has been realized by a device having the characteristics of patent claim  1  for supporting the vertebral column.  
      The main advantage of the present invention is that the provided chin rest pad attached to the chin strap of the helmet provides special support for the head with the chin on the rest pad on one side and support for the rest pad on the front pressurized cushions on the other side, wherein particularly the existing gap between the front end areas of the front pressurized cushions is bridged over by the rest pad. Since the rest pad can easily slide on the front pressurized cushions, it is now possible to move the head conveniently. This also prevents the head from entering into the said gap between the front end areas of the front pressurized cushions and the resulting injury during strong head movements toward the front.  
      Further advantages of the present invention are that in case of g-loads, the forces affecting the head with the helmet of a pilot are partly compensated on the chin joint and the occipital squama, wherein the front pressurized cushions at the chin joint take over the compensation in case of a head tilt of up to preferably 30 degrees toward the front and up to more than 17 degrees toward the back. The back pressurized cushions at the occipital squama take over the compensation in case of a head tilt from preferably 22 degrees to preferably more than 40 degrees toward the back. The head is not supported in case of an almost upright position from approximately 17 to 22 degrees to the front and to the back and about 5 degrees sideward. The centers of gravity of the head and helmet system almost overlap each other. The relevant g-forces on the vertebral column are moderate in this position of the head since the g-force component is small compared to the countering forces provided by the neck musculature. The specified angular degrees refer to the head position of 0 degrees, in which the center of gravity of the head respective to the mass of helmet/head lies vertically over the fulcrum on the vertebral column.  
      During operation without a g-load in case of a head tilt a small amount of pressure in the pressurized cushions maintains the cushions upright and against the head. Thus almost full freedom of movement is ensured in case of or with little counter bearing pressure.  
      In case of a g-load up to 6 g the quantum and the vector of the load in relation to the head position at the moment of this action are recorded by a g-sensor and a control and regulation unit provides a countering force to the cushions for the g load to be counter controlled as a result. Each time, an appropriate control valve actuates the corresponding pressure pillow, till the default bearing pressure at the head is achieved. Force sensors on the surface of the pressurized cushions record the force on the head. This force is compared with a set value in the control and regulation unit and eventually the corresponding control valve is activated to achieve a pressure reduction in the pressurized cushion. In case of an intended movement of the head, the musculature applies an additional small amount of pressure on the force sensors. The control and regulation unit steer the pressure back and thus enable a movement in the intended direction. In case of an acceleration of over  6  g., the control valves to the pressurized cushions are opened for maximum pressure supply and then completely closed. The head is supported in the case of these loads. The target is not to achieve a controlled freedom of movement because this is physically not feasible. The mechanism effectively relieves the cervical vertebral column of stress by up to approximately 60% and the stress on the neck musculature by up to almost 100% depending on the position of the head and the location of the center of gravity.  
      Normally in cases of a high g-load, injuries of the cervical vertebral column are expected to occur due to a resulting force that amounts to as much as 2.0 times the weight. The device, according to the invention can effectively avoid such injuries. Likewise the invention can prevent stress on the neck musculature that normally leads to exhaustion, blackouts, neurological deficits, coordination disturbances, headaches, partial performance disturbances and a diminished ability to concentrate.  
      A further advantage of the present invention is that by using the helmet display, displayed images and information can be seen by the pilot vibration free, because the present device stabilizes the head-helmet system.  
      Dependent claims of this patent further elaborate on the merits of this invention. 
    
    
      The invention and its arrangements are explained in better detail in the context of the following figures. The figures illustrate:  
       FIG. 1 : a schematic representation for the explanation of the invention in which the weight center of the head, the pivot point (fulcrum) between the cervical vertebral column and the head and the application of force on the neck musculature are shown.  
       FIG. 2 : a perspective representation of a preferred pattern of construction of the device according to the invention, essentially consisting of the resting pad attached to the chin strap of a helmet, the front pressurized cushions with hard surface for the adhesion with the head part and the shoulder part with the resting case;  
       FIG. 3 : a schematic block diagram of the control and regulation unit for the explanation of the control of the pressure build-up and pressure reduction in a pressurized cushion; and  
       FIG. 4 : a further training of the invention. 
    
    
      The invention was the result of the following deliberations. According to  FIG. 1  the head  1  of a pilot is twisted around the pivot point O with reference to the cervical vertebral column  2 . The pivot point O is located at the upper end of the cervical vertebral column  2 . The turning takes place through the neck&#39;s muscular system that acts on the head  1  in point F. The tilting movement of the head  1  operates in the opposite direction. The tilting movement arises from the weight of the head  1  and tries to turn the head  1  around the pivot point O. It is noticeable that while wearing a helmet, especially one fixed with additional equipment like for instance sight or after-sight devices, the weight of the head  1  and consequently also the tilting moment around the pivot point O are greatly increased. The corresponding vector is indicated in the  FIG. 1  with V. In order to avoid the pressure on the head from the front end areas of the front cushions during a large g-load and when the head  1  tilts toward the front, such that the function of the cushion is not affected, according to the invention, a rest pad  4  is attached at the helmet H, favorably at the belt component K of the helmet H on the side turned toward the front cushions  5 ,  6 . This resting pad  4  can glide on the surface of the front cushions  5 ,  6 , in the normal head position indicated in  FIG. 1  without a g-load, during a head tilt in case of little pressure in the front cushions  5 ,  6 . Thus an adhesion of the front cushions  5 ,  6  with the head  1  is maintained. It is also then possible to turn the head conveniently. Almost total freedom of movement can be ensured with minimal countering pressure.  
      In case of a high g-load (up to 6 g), the quantum and the vector of the force in relation to the head position at the moment of the exposure are recorded by sensors and the control and regulating unit applies a countering force to the cushions that as a result have to be counter controlled till a preset bearing pressure on the head  1  is attained. During an intended movement of the head  1  an additional small amount of pressure is applied by the muscular system to the force sensors of the respective front cushions  5 , 6 , so that the control and regulating unit steers the pressure back and consequently can let a movement in the intended direction. In case of a very big acceleration (over 6 g) the cushions are actuated for a maximum pressure impact, so that the head  1  is fully supported during these stresses. A controlled freedom of movement is not aimed for, because this is not feasible physically. By this mode of operation of the cushions and of the sliding overlying rest pad  4 , depending on the position of the head and location of the center of gravity, a reduction of the stress of the cervical vertebral column  2  by up to approximately 60% and a reduction of stress on the neck muscular system by up to almost 100% can be achieved.  
      According to  FIG. 2  the front cushions  5 ,  6  and the back cushions  7 ,  8  are fastened at the guard zone of an upper opening  12  of a rest case  10 . This rest case  10  overlies on the neck and shoulder area of a pilot. The rest case  10  shows in the forefront a port shaped opening  14  that passes downward which can be widened for putting on the rest case  10 , and after that is attachable by drawing together the port shaped opening  14  with the help of at least one locking mechanism  16  running in cross direction which might be a Velcro fastener for instance.  
      The back cushions  7 ,  8  lie on the upper side of the occipital squama of the head  1 . The front cushions  5 ,  6  show integrated stiffening elements  18 ,  20 , on which the rest pad  4  can be supported. Each of the cushions  5 ,  6 ,  7 ,  8  is fillable with the help of a fluid, especially a gel, as will be explained in better detail later, so that it can expand in the effective direction to support the head  1  of the pilot. It has been indicated that the cushions  5 ,  6 ,  7 ,  8  can be effectively padded using foam cushion towards the outside, inside and upwards.  
      If the rest case  10  overlies on the shoulder area of a pilot and the locking  16  is locked, the upper sides of the back cushions  7 ,  8  lie at the occipital squama of the head  1  of the pilot and the upper sides of the front cushions  5 ,  6  are turned toward the sideward lower jaw areas of the pilot with their stiffening elements  18 ,  20 . The rest pad  4  is fastened to parts of the chin belt  22 ,  24  of the helmet H that is not represented in  FIG. 2 . It is formed such that in the normal state it can overlie on the upper sides of the stiffening elements  18 ,  20  and/or of the wrapping of the front cushions  5 ,  6  that covers these, such that it can freely glide on the cushion when the head  1  of the pilot turns. A pushing through of the chin area of the head - 1  is avoided, because the rest pad  4  bridges over the gap between the front end areas of the front cushions  5 ,  6  with its front area  4 ′. The side areas  4 ″ are formed stretching obliquely outwards from the front area  4 ′ and overlie upon the front cushions  5 ,  6  when the head  1  is upright, so that the sliding motion of the rest pad  4  cannot be obstructed.  
      A force sensor  26  is placed on the upper side of each cushion  5 ,  6 ,  7 ,  8 . It is a piezoresistive pressure sensor that emits an output voltage between 0 Volt and 10 Volt as an output signal. This depends on the pressure applied to it and to the respective cushion.  
       FIG. 3  shows a schematic block diagram of a control and regulating unit for the production and supply of pressure on each cushion  5 ,  6 ,  7 ,  8 , wherein only one cushion  6  has been illustrated in  FIG. 3  as an example. A compressor  30  produces the required operating pressure in a reservoir  32 . The compressor  30  is connected to the cushion  6  via a duct  34  and a regulating valve  36  for pressure-buildup. The regulating valve  36  is activated via an actuator  38  that is activated by the electronic unit  40 . In the duct  34  between the regulating valve  36  and the pressure cushion  6  there is a branch circuit  44  with a discharge valve  46 , via which the built up pressure of cushion  6  is relieved with its activation by the actuator  48 , which is also activated by the electronic unit  40 .  
      The electronic unit  40  receives an output signal from a 3D-vectorial g-force sensor via the wire  50 . This signal contains information about the respective g-force in three-dimensional space. Depending on this signal, the electronic unit  40  produces corrective signals for the pressure supply of the cushion  6  via the regulating valve  36  and/or via the discharge valve  46  for the pressure relief of cushion  6 . The pressure sensors  26  of the cushions  5 ,  6 ,  7 ,  8  supply via the wire  52 , a pressure signal to the electronic regulating unit  40  indicating the respective pressure in the pressure cushion  6 . A range sensor  56  can be provided in order to supply a range signal to the electronic unit  40  via the wire  54 . The signal indicates the actually occurring expansion of the cushion  6  after application of pressure via the regulating unit  36 .  
      The front cushions  5 ,  6  can show on the inner surface in each case indentations  28  in the stiffening elements  18 ,  20 , as illustrated schematically in the  FIG. 4 . The indentations can be covered by the wrapping and can prevent an injurious squeeze of the  carotis communis  arteries and of the  Ingularis  veins. Such indentations do not adversely affect the support of the front cushions  5 ,  6  on the lower jaw areas in the present invention, because they are covered on the upper sides by the rest pad  4 .  
      The present device can also be used effectively for the compensation of vibration stresses occurring while flying in helicopters and caused by the rotor blades of helicopters where the sinusoidal vibrations of this kind lie in the frequency range of 30 to 100 Hz, and/or in case of sonic frequencies or frequencies of over 300 Hz transmitted by GFK-aircraft cells with an approximately 0.15 oscillating g-acceleration and in case of a longer lasting acceleration of an approximate maximum of 4 g. The vibration stresses originate from either the stimulation of the head by way of the pilot seat and also in case of higher frequencies by the sound pressure of the rotor directly on the helmet via the cabin roof airway. The so-called PIOS (Pilot Induced Oscillations) can also be compensated.