Abstract:
An ice tip is placed on the front end of a hypodermic needle to cool the flesh during insertion. The ice tip front end is sharp, for penetration, and the rear is provided with a recess, for reception of a hypodermic needle front end. The mold for forming the ice tip can be cooled by a cryogenic fluid being conducted into a main mold surrounding a tip forming heat conducting mold that is used to form the ice tip pointed front end and the recessed rear end.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention is to a frozen water hypodermic needle tip to make an injection reasonably pain free. 
         [0003]    2. Description of Related Art 
         [0004]    The use of cold surfaces and cryogenic fluids to cool the skin where injection or cutting is to take place per se is old and obvious. Examples of prior art patents that use various means to cool the skin or needle include: U.S. Pat. No. 2,746,264 issued May 22, 1956, to F. G. Keyes; U.S. Pat. No. 3,333,587 issued Aug. 1, 1967 to R. D. Johnston; U.S. Pat. No. 3,351,063 issued Nov. 7, 1967, to Malaker et al; U.S. Pat. No. 3,399,675 issued Sep. 3, 1968, to C. W. Hill, U.S. Pat. No. 3,483,869 issued Dec. 16, 1969, to M. J. Hayhurst; U.S. Pat. No. 3,605,742 issued Sep. 20, 1971, to R. C. Tibbs; U.S. Pat. No. 4,646,735 issued Mar. 3, 1987, to J. S. Seney; U.S. Pat. No. 4,725,265 issued Feb. 16, 1988, to M. Sairenji; U.S. Pat. No. 5,236,419 issued Aug. 17, 1993, to J. S. Seney; U.S. Pat. No. 6,936,028 issued Aug. 30, 2005, to Hommann et al; U.S. Pat. No. 7,097,641 issued Aug. 29, 2006, to Arless et al. 
       SUMMARY OF THE INVENTION 
       [0005]    A hypodermic needle is provided with an ice tip for cooling and penetrating the skin of a patient. The tip is secured to the front end of a blunt or standard cannula. The ice tip is held on the cannula by a flange at the rear of the tip. The tip can be frozen at the place of manufacture or use, using a cryogenic fluid. On exposing the tip to the warmth of the atmosphere or body of a patient, the flange and tip begin to melt permitting the injection of a fluid through the cannula of a hypodermic needle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a side cross-section of a modified hypodermic needle having an ice tip. 
           [0007]      FIG. 2  is a side view and an ice tip separated from the hypodermic needle. 
           [0008]      FIG. 3  is a side cross-section of a hypodermic needle tip mold for use with a cryogenic fluid. 
           [0009]      FIG. 4  is a side cross-section of a standard hypodermic needle used with an ice tip. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0010]    The invention is to a frozen hypodermic needle tip to make an injection as painless as possible. The needle tip is designed to be used with a modified needle structure or a standard needle structure. The ice tipped cannula  1  is shown in  FIG. 1 . A modified cannula shank  2  has a blunt front end  3  with an ice tip  11  secured to the front blunt end. The ice tip  11  has a rear flange  12  that fits over the front end  3  of the cannula  2 . The flange has a thickness of from 0.010 to 0.025 inch. The front end of the cannula extends into the recess formed by the flange  12  to the recess base  13  in the ice tip. The recess has a depth of from 0.060 to 0.250 inches. The ice tip extends from the rear flange  12  rear extreme  18  to the forward front tip end  15  in straight or curved side surfaces  14 . The ice tip has an overall length of from 0.250 to 1.250 inches. 
         [0011]    It is known that a person suffers less or is not as sensitive to hypodermic needles where the skin or flesh surface is cold. The ice needle tip serves to cool the skin to reduce both pain and apprehension. Since the atmospheric temperature and body temperatures are both higher than the ice, as soon as the hypodermic ice tip is exposed it begins to melt the surface, The wet needle ice tip performs the function of assisting heat transfer from the flesh surface to the ice tip; and acting as a lubricant. The ice tipped cannula  1  is inserted using the tip front end  15 . The rear flange of the ice tip is thin and quickly melts when inserted into the body or body part. With the flange melted, fluid can be injected through the cannula shank  2  past the blunt front end  3  and into the body or body part. With the ice tip body  11  having more mass, it takes longer to melt but, due to the relative overall size of the ice tip, there will be no adverse effect to the body part or blood therein 
         [0012]    The ice tipped cannula  1  can be “factory manufactured” with the cannula shank  2  and ice tip body  11  formed together for both shipment and use or they can be placed together, for example, at the point of use. 
         [0013]    In  FIG. 2 , a side view of the cannula shank  2  and ice tip  11  are shown separated as would be done if the ice tip were to be inserted at the point of use. The cannula shank front end  3  is pressed into the ice tip recess  19  to the base  13 . 
         [0014]    In  FIG. 3 , a cross-section of one example of a mold that could be used to manufacture the ice tip at a factory or point of use is shown. The primary mold  20  includes a cover  31  for the tip cavity  16  with projections  32 , that can be tapered for easy removal, used to form a recess  19  in the tip rear base  13 . The mold main body has ends  21  and bottom  25  and optional top  28 . The end of the main body is provided with an access  22  having an access opening  23  for introduction of a cryogenic fluid with an exit opening provided (not shown). The individual tip molds  27  have tip shape openings  16  filled with water to be frozen. A point shape cavity  26  front end  24  extends to the main mold body bottom  25 . The individual tip molds  27  are made of a highly thermally conductive material that may be the same as or different from that of the main mold body  20 . The sides can be tapered for easy removal of the tip  16 . The water in the tip shape opening  16  is frozen by introduction of a cold or cryogenic fluid into the mold through the opening  23  in the end  21  of the main mold body. 
         [0015]    To avoid the need for refrigeration, a die can be provided with a cryogenic fluid dispenser for freezing water in the die  20  as shown in  FIG. 3 . To accommodate this, the die is provided with internal passages  28  for conducting cryogenic fluid past the cannula cavity  2  in the die to an exit opening  29  in the front end of the die. A cryogenic fluid adapter  30  closes the cannula cavity rear end. The cryogenic fluid adapter is provided with a threaded cryogenic fitting for supplying a cryogenic fluid from a cryogenic dispenser. An inlet  32  connects with a groove  33  extending around the base of the cryogenic adapter  30  that alines with the cryogenic passages  28  that extend around and along the cannula cavity  22  for removing heat from the cavity and any water or ice in the cannula cavity. The cryogenic fluid adapter  30  is secured on the die with adapter locks  34  that are locked and removed by turning the adapter  30  relative to the die  20 . The die  20  can be slid off  38  the frozen hypodermic needle. 
         [0016]    In  FIG. 4  an alternate ice tip  16  is shown. The tip  16  is provided with a recess  17  that will accept a standard cannula shank  4  with a tapered front bevel  5  with point  6 . The recess  17  extends into the ice tip from the rear surface for from 25% to 75% of the length of the ice tip. 
         [0017]    It is believed that the construction, operation and advantages of this invention will be apparent to those skilled in the art. It is to be understood that the present disclosure is illustrative only and that changes, variations, substitutions, modifications and equivalents will be readily apparent to one skilled in the art and that such may be made without departing from the spirit of the invention as defined by the following claims.