Patent Abstract:
The present invention provides a tweezer for dental and other applications. The tweezer including a main body portion ( 12, 14 ) extending in a generally longitudinal direction. The main body portion having a first end ( 20 ) and a second end ( 18 ). A hinge connector ( 16 ) is located between the first end and the second end. A first pair of pincers is located at the first end ( 20 ). A second pair of pincers is located at the second end ( 18 ). A bias mechanism ( 22 ) urges the first pair of pincers ( 20 ) into a closed position and urging the second pair of pincers ( 18 ) in an open position, whereby the user may apply a force to the tweezers to overcome the bias mechanism ( 22 ) and urge the first pair of pincers ( 20 ) away from the closed position and the second pair of pincers ( 18 ) away from the open position.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority to New Zealand Application No. 602561, filed Sep. 21, 2012, the entire contents of which are hereby incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of dental instruments and more specifically to dental tweezers. The invention may also find application in other fields where tweezers are utilized. 
       BACKGROUND OF THE INVENTION 
       [0003]    Tweezers are instruments used to pick up objects that are too small to be easily handled using human hands. A majority of dental products are small and require the use of tweezers. Dental tweezers come in a variety of sizes and shapes. Dentists usually use more than one type of tweezer during a single procedure. Most tweezers require the application of constant pressure while gripping an object. This requirement is a difficulty when the dental assistant needs to pass the dental product to the dentist. This requirement also doesn&#39;t allow for preloading of the tweezers. 
         [0004]    Although there are several dental tweezers in prior art (U.S. Pat. No. 6,776,615 B2, U.S. Pat. No. 7,938,469 B2, U.S. Pat. No. 6,142,781 and U.S. Pat. No. 5,060,329), these tweezers don&#39;t have tweezers at both ends and also they don&#39;t allow for preloading. The current invention aims to address drawbacks in prior art. 
       SUMMARY OF THE INVENTION 
       [0005]    The object of this invention is to provide an instrument that can be used for different purposes and which allows for preloading. The device is a double-ended tweezer wherein both ends include a pair of pincers, and one end is biased in a closed position and the other end is biased in an open position. 
         [0006]    The present invention provides a tweezer for dental and other applications, the tweezer comprising a main body portion extending in a generally longitudinal direction. The main body portion having a first end and a second end. A hinge connector is located between the first end and the second end. A first pair of pincers is located at the first end and a second pair of pincers located at the second end. A bias mechanism urging the first pair of pincers into a closed position and urging the second pair of pincers in an open position, whereby the user may apply a force to the tweezers to overcome the bias mechanism and urge the first pair of pincers away from the closed position and the second pair of pincers away from the open position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a double-ended tweezer in accordance with one embodiment of the present invention, in a passive configuration; 
           [0008]      FIG. 2  is a perspective view of a spring of the double-ended tweezer of  FIG. 1 ; 
           [0009]      FIG. 3  is a close-up detail of the hinge connector portion of the second lever of the double-ended tweezer of  FIG. 1 ; 
           [0010]      FIG. 4  is a plan view of the fastener of the double-ended tweezer of  FIG. 1 : 
           [0011]      FIG. 5  is a top plan view of a double-ended tweezer in accordance with another embodiment of the present invention, in a passive configuration; 
           [0012]      FIG. 6  is a side plan view of the double-ended tweezer of  FIG. 5 ; 
           [0013]      FIG. 7  is a close-up detail of the cotton tweezer end of the second lever of the double-ended tweezer of  FIG. 5 , showing the pin; 
           [0014]      FIG. 8  is a close-up detail of the cotton tweezer end of the first lever of the double-ended tweezer of  FIG. 5 , showing the pin hole; 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]      FIG. 1  shows a perspective view of a double-ended tweezer  10  for dental procedures in accordance with one embodiment of the present invention. The double-ended tweezer  10  includes a first lever  12  and a second lever  14 . The first lever  12  is coupled to the second lever  14  via a fulcrum or hinge connector  16 . The double-ended tweezer  10  includes a pair of pincers at both ends  18 ,  20 . In particular, the double-ended tweezer  10  includes a cotton tweezer end  18  and a pin tweezer end  20 . 
         [0016]    The hinge connector  16  couples the first lever  12  and second lever  14  in a pivotal manner. The hinge connector  16  includes a spring  22  which biases the tweezer  10  in a passive position as shown in  FIG. 1 . In the passive position of  FIG. 1 , the pin tweezer end  20  is urged toward a closed arrangement and the cotton tweezer end  18  is urged towards an open arrangement. The hinge connector  16  also includes a fastener  24  for maintaining the first lever  12  and second lever  14  in a biased pivotal connection. 
         [0017]      FIG. 1  also shows that the first lever  12  includes gripping portions  30 . Although not readily seen, it will be appreciated that second lever  14  also includes gripping portions  30 . The gripping portions may be a series of grooves machined or otherwise provided in the levers. Alternatively, the gripping portions  30  may be provided on one side of a one-sided adhesive label. The other side of the label having the adhesive for applying and retaining the gripping portion  30  to the respective lever. The gripping portions  30  may take the form of other embodiments as will be appreciated. 
         [0018]    The spring  22  is shown in  FIG. 2  to be a keyhole shaped flat metal spring. The spring  22  includes a curved portion  32  with legs  34  extending from the curved portion  32 . The spring  22  provides a height “h”. The spring  22  includes a transition portion  36  between the curved portion  32  and the respective leg  34 . The legs  34  each terminate at ends  38 . The first lever  12  includes an outer wall  40  and an inner wall  42 . Similarly, the second lever  14  includes an outer wall  44  and inner wall  46 . The cotton tweezer end  18  is shown to include a gripping portion  48  on the opposed facing inner walls  42 ,  46 . The gripping portion  48  may be parallel ribbing, slightly offset so as to provide an overlapping engagement. The inner wall  48  includes a rectangular recess  50  for receiving and retaining a respective end  38  of the spring  22 . The inner wall  42  includes a similar recess  50  (not shown) in opposed facing relation with the recess  50  of the inner wall  46 . 
         [0019]      FIG. 1  shows that the portion of the levers  12 ,  14  extending from the hinge connector  16  to the cotton tweezer end  18  is longer than the portion of the levers  12 ,  14  extending from the hinge connector  16  to the pin tweezer end  20 . This arrangement accommodates the longer length desired for the cotton tweezers end  18 , yet avoids an unduly long overall length of the tweezers  10 . 
         [0020]      FIG. 3  shows a close up exploded view of the second lever  14 . In particular, a pivot seat  52  is shown. The pivot seat  52  extends from the inner wall  46  of the second lever  14  via a flange portion  54  (see  FIG. 1 ). The pivot seat  52  includes a C-shaped annular spring abutement  56 . A cylindrical spring wall  58  extends from the annular spring abutement  56  and defines a height of the wall  58 . The cylindrical spring wall  58  is interrupted by nub  60  which forms a pair a spring leg abutements  62 . The nub  60  has a width as defined by the spring leg abutement  62 . A hole  64  extends through the pivot seat  52 , including the annular spring abutement  56  and cylindrical spring wall  58 .  FIG. 3  also shows the rectangular recess  50  for receiving and retaining an end  38  of the spring  22 . The depth of the rectangular recess  50  is shown to increase as the rectangular recess  50  extends away from the pivot seat  52 .  FIG. 3  also shows that the inner wall  46  includes a curved recessed portion  66  opposite the pivot seat  52 . The recessed portion  66  accommodates the curved portion  32  of the spring  22 . 
         [0021]    The first lever  12  includes a similar pivot seat  52  and accordingly the same reference numerals are used. However, alternatively, the corresponding wall  58  may provide a height the same or different from the height of the wall  58  of the second lever  14 . Regardless, the combined height of both walls  58  may be slightly greater than the height “h” so as not to bind the spring  22 . Further, the width of the nub  60  may be narrower than that of the second lever  14 . In this manner, the nub  60  of the first lever  12  will not interfere with the spring  22  during pivoting action of the tweezer  10 . In addition, the hole  64  may be formed of a different dimension from the hole of the second lever  14 . The variation in dimension is intended to accommodate particular fastener  24  as will be appreciated from the following comments. 
         [0022]      FIG. 4  shows the fastener  24 . The fastener  24  includes a slotted head  70 , a pivot shank  72  and an end shank  74 . The pivot shank  72  includes a diameter which is slightly less than the diameter of the hole  64  in the pivot seat of the first lever  12 . The end shank  74  includes a diameter which provides an interference fit with the hole  64  in the pivot seat  52  of the second lever  14 . Alternatively, the hole  64  in the pivot seat  52  of the second lever  14  may be threaded, with the end shank  74  having a mating threaded arrangement. Other fastener arrangements are contemplated as will be understood. 
         [0023]      FIG. 5  shows a top plan view of a double-ended dental tweezer  110  in accordance with another embodiment of the present invention, in a passive configuration. Where features are similar to the first embodiment, similar reference numerals are used. In this embodiment, the hinge connection  116  is located at a mid-portion of the double-ended dental tweezer  110 .  FIG. 6  is a side plan view of the double-ended dental tweezer of  FIG. 5 .  FIG. 7  is a close-up detail of the pin tweezer end  120  of the second lever  114  of the double-ended dental tweezer  110  of  FIG. 5 , showing the pin  176 .  FIG. 8  is a close-up detail of the pin tweezer end  120  of the first lever  112  of the double-ended dental tweezer  110  of  FIG. 5 , showing the pin hole  178  for receiving the pin  176 . 
         [0024]    In the two embodiments shown above, at one end is a combination pin and hole arrangement and at the other end cotton tweezers ends. In yet another embodiment, the ends are the same, e.g., cotton tweezers ends. Other embodiments are also possible and contemplated. The double-ended tweezer may be made of metal. However, other materials are possible and keeping within the spirit of the invention. 
         [0025]    The pin-end allows for better gripping of objects that have a hole through them. The pin-end also allows for preloading of the tweezers. A spring keeps the pin-end arms closed. The spring may be inbuilt or separate to the hinge connector. 
         [0026]    The device works such that the dentist can handle small dental accessories using one set of tweezers. In the passive configuration, the distal side of the device is open and the proximal side is closed by a spring. The dentist has to apply pressure on the two levers to grip objects at the distal ends. At the proximal end, pressure is applied to open the ends. Once the object has been gripped, the device can be used without the application of pressure. This allows for preloading of the device and for secure handling of the object and device at the chair-side. 
         [0027]    The distal side of the device is used for general purposes and the proximal side is used for dental products that allow the use of the pin-ends. 
         [0028]    While the present invention has been described in connection with a specific application, this application is exemplary in nature and is not intended to be limiting on the possible applications of this invention. It will be understood that modifications and variations may be effected without departing from the spirit and scope of the present invention. It will be appreciated that the present disclosure is intended as an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated and described. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims.

Technology Classification (CPC): 0