Patent Publication Number: US-2010113993-A1

Title: Force-multiplying percussor

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
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     INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
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     TECHNICAL FIELD 
     The field of the invention is percussors. A percussor is a medical device for supplying impulse forces to a patient&#39;s back or chest for the purpose of loosening and dislodging bronchial secretions in the lungs. 
     BACKGROUND ART 
     The present invention is of a type of percussor based on the use of a solenoid in developing inpulse forces for application to a patient&#39;s back or chest. A “solenoid”, as defined in the McGRAW-HILL DICTIONARY OF SCIENTIFIC AND TECHNICAL TERMS, Fourth Edition, Sybil P. Parker, Editor in Chief, McGraw-Hill Book Company, New York, N.Y., 1989, is “a coil that surrounds a movable iron core which is pulled to a central position with reepect to the coil when the coil is energized by sending current through it.” 
     An example of this type of percussor is described in U.S. Pat. No. 4,512,339 as a device which energizes a coil to develop an impulse force for application to a patient and utilizes a compressed spring to return the movable iron core to its rest position. The designs of percussors of this type are unnecessarily complicated and inflexible with respect to their use in treating patients and the adjustment of the operating parameters of the devices. 
     The present invention avoids the complexities and inflexibilities of the prior art by utilizing a solenoid in a new and different way in generating impulse forces. The present invention utilizes the solenoid only for returning the movable iron core to its rest position. The patient-experienced impulse forces that result from the present invention are multiplied versions of the continuing force applied by a technician in using the invention. 
     DISCLOSURE OF INVENTION 
     The invention is a force-multiplying percussor comprising an anvil, a hammer, a coil, and a pulse generator. 
     The anvil is equipped with a force-receiving surface and a force-delivering surface which are rigidly connected together, the force-delivering surface being intended for contact with a patient&#39;s body. 
     The hammer is also equipped with a force-receiving surface and a force-delivering surface, the hammer being attached to the anvil in such a way that the force-delivering surface of the hammer and the force receiving surface of the anvil are mechanically free to come together or move apart. 
     The coil forces the force-delivering surface of the hammer and the force-receiving surface of the anvil to separate when the solenoid is energized with an electrical current. 
     The pulse generator supplies repeated electrical current pulses to the coil which causes repeated force-multiplied impulse forces to be applied to a patient&#39;s body via the force-delivering surface of the anvil whenever the technician applies a continuing force to the force-receiving surface of the hammer. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of the invention. 
         FIG. 2  is a sectional view in a plane containing the axis of symmetry of the first embodiment of the invention shown in  FIG. 1  with the hammer shown in an arbitrary position relative to the anvil. 
         FIG. 3  is a sectional view of the first embodiment similar to that of  FIG. 2  except that the hammer is shown fully-withdrawn from contact with the anvil. 
         FIG. 4  is a perspective view of a second embodiment of the invention. 
         FIG. 5  is a sectional view in a plane containing the axis of symmetry of the second embodiment of the invention shown in  FIG. 4  with the hammer shown in an arbitrary position relative to the anvil. 
         FIG. 6  is a sectional view of the second embodiment similar to that of  FIG. 5  except that the hammer is shown in contact with the anvil. 
         FIG. 7  shows the inputs and outputs of the pulse generator which supplies the driving current for the invention. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     A first embodiment  1  of the invention is shown in  FIG. 1 . It consists of a hammer  3  and an anvil  5 . The device is placed on the back or chest of a patient with the anvil in contact with the patient&#39;s body. The technician holds the device in place by gripping the hammer  3  with one hand, palm on top, and then turns on the power. The force continually applied by the technician to the hammer is converted by the device into repeated force-multiplied impulses in which the force associated with each impulse is significantly greater than the force being applied by the technician on a continuing basis. 
     The details of the device design are shown in the sectional view of  FIG. 2 . Hammer  3  consists of a plastic structural member  7  attached to guiding member  11 . Guiding member  11  may be either metal or plastic and attaches to structural member  7  utilizing mating threaded regions. Coil  9  is embedded in structural member  7  as shown (assuming structural member  7  is a plastic material). 
     Anvil  5  consists of ring  15  and platen  17  connected together by cylindrical guiding member  19 . Ring  15  has a rectangular cross-section and is made of a magnetic material such as iron. Guiding member  19  attaches to ring  15  by a press fit. Platen  17  is attached to guiding member  19  by means of a machine screw. 
     If there is no current flowing through coil  9 , hammer  3  is free to slide back and forth along guiding member  19  subject only to the constraints imposed by the combination of structural member  7  and guiding member  11 . Current flowing through coil  9  generates a magnetic field which exerts a force on ring  15  causing hammer  3  and anvil  5  to assume the relative positions shown in  FIG. 3 . 
     Let us now assume that a technican places the percussor against a sitting patient&#39;s back in the gentlest possiable way and coil  9  is energized by a series of current pulses. Hammer  3  and anvil  5  will assume the positions shown in  FIG. 3  and remain in those positions for as long as the technician does not apply a force to force-receiving surface  23 . 
     Now assume that the technician begins to apply a force to force-receiving surface  23  while the coil is energized with a current pulse. Nothing happens because the magnetic force holding hammer  3  and anvil  5  in the relative positions of  FIG. 3  is greater than that applied by the technician. 
     When the current pulse ends, the magnetic force opposing the force applied by the technician disappears and the force-delivering surface  25  of hammer  3  strikes the force-receiving member  27  of anvil  5  thereby delivering a considerably greater force to platen  29  and the patient&#39;s back with which it is in contact. The process repeats with each current pulse supplied to coil  9 . 
     The work expended by the technician is the product F t d h  of the force F t  applied by the technician and the distance d h  traveled by the hammer before striking the anvil. The technican&#39;s work is converted into kinetic energy of the hammer. This kinetic energy is disipated when the hammer strikes the anvil and the anvil depresses the patient&#39;s flesh. The kinetic energy is converted into potential energy associated with the depresseion of the patient&#39;s flesh and heat. The technician&#39;s work is balanced by the work F p d p  expended by the patient&#39;s body which resists the anvil  5  with a force F p  over a distance d p . Thus, the effective force applied by the anvil to the patient&#39;s body is given by F p =(d h /d p )F t . 
     The quantity (d h /d p ) is typically greater than three and consequently the percussor described herein typically has a force-multiplying effect. For example, a technician&#39;s force of 10 lbs is typically experienced as a force of 30 lbs or more by a patient. 
     A second embodiment  31  of the invention is shown in  FIG. 2 . It consists of a hammer  33  and an anvil  35 . Like the first embodiment, the device is placed against the back or chest of a patient with the anvil in contact with the patient&#39;s body. The technician holds the device in place by gripping the hammer  33  with one hand, palm on top, and then turns on the power. The force continually applied by the technician to the hammer is converted by the device into repeated impulses in which the force associated with each impulse is significantly greater than the force being applied by the technician on a continuing basis. 
     The design details for the second embodiment are shown in the sectional view of  FIG. 5  taken in a plane containing the axis of symmetry of the device shown in  FIG. 4 . 
     Hammer  33  consists of a plastic body  37  in which is embedded a core  39  made of a magnetic material such as iron. 
     Anvil  35  consists of a plastic body  41  in which is embedded coil  43  which surrounds core  39  when hammer  33  is inserted into anvil  35 . 
     Like the first embodiment, if there is no current flowing through coil  43 , hammer  33  is free to slide back and forth within anvil  35  but limited in range by three pins anchored in the curved wall of anvil  35  and terminating in three vertical grooves spaced 120 degrees apart in hammer  33 . 
     Current flowing through coil  43  generates a magnetic field which exerts a force on core  39  causing hammer  33  and anvil  35  to assume the positions shown in  FIG. 5 . 
     Let us again assume that a technican places the percussor against a sitting patient&#39;s back in the gentlest possiable way and coil  9  is energized by a series of current pulses. Hammer  33  and anvil  35  will assume the positions shown in  FIG. 5  and remain in those positions for as long as the technician does not apply a force to force-receiving surface  51 . 
     Again assume that the technician begins to apply a force to force-receiving surface  51  while the coil is energized with a current pulse. Nothing happens because the magnetic force holding hammer  33  and anvil  35  in the relative positions of  FIG. 3  is greater than that applied by the technician. 
     When the current pulse ends, the magnetic force opposing the force applied by the technician disappears and the force-delivering surface  53  of hammer  33  strikes the force-receiving member  55  of anvil  35  as shown in  FIG. 6 . Hammer  33  thereby delivers a considerably greater force to the patient&#39;s back with which it is in contact, as discussed above. 
     For as long as the technician maintains a force on hammer  33 , the process repeats with each current pulse supplied to coil  43 . 
     The pulse generator required to drive the percussor&#39;c coil is shown in  FIG. 7 . It operates with standard 120 VAC input power and has means for controlling the widths and the repetition rate of the output pulses. 
     INDUSTRIAL APPLICABILITY 
     The invention is a medical device for supplying impulse forces to a patient&#39;s back or chest for the purpose of loosening and dislodging bronchial secretions in the lungs, thereby having industrial applicability.