Abstract:
A folding knife incorporating an opening assist mechanism that enables the blade from a closed to open position by providing a spring for selective initial blade engagement. A single integral bifurcated spring acts to continuously engage a spring urge locking bar retaining the blade in open locked position and to provide initial spring urged deployment of the blade from blade closed position to blade locked open position during user initiated deployment.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    This invention relates to folding knives that provide for a knife blade to be pivoted into the handle when not in use. Such folding knives are opened by manual engagement of the blade, pulling it out of the handle and moving it to an open locked use position. 
         [0003]    2. Description of Prior Art 
         [0004]    Prior art folding knives provide for a blade engagement mechanism that holds the blade in either closed, safely stored position or in extended open and locked use position out of the handle. 
         [0005]    Some folding knives are equipped with a so-called assist opening mechanism that typically provides for a spring to hold the blade in closed “folded position” within the handle and then to assist the blade to move to a fully opened locked position. 
         [0006]    Thus, as a user would manually first engage the blade from a fully closed position the spring mechanism engages the blade and completes the blade rotation to a fully opened and locked position thus assisting in the opening. 
         [0007]    Examples of a variety of such assisted opening folding knives can be seen in U.S. Pat. Nos. 6,959,494, 7,080,457, 7,086,157, 7,107,686, 7,146,736, 7,293,360, 7,313,866, 7,562,454, 7,676,932, 7,748,122 and U.S. Publications 2005/0097754, 2007/0068002, 2007/006800 and 2009/0056146. 
         [0008]    U.S. Pat. Nos. 6,959,494, 7,080,457, 7,107,686, U.S. Publication 2005/0097754 and U.S. Pat. No. 7,313,866 all use a combination or specific coil spring configuration to engage and rotate the knife blade from an almost closed position to a fully opened extended and locked position. 
         [0009]    U.S. Pat. No. 6,959,495 uses a camming mechanism secured to the blade on which the coil spring engage. 
         [0010]    U.S. Pat. No. 7,080,457 has a connecting rod from a spring to a blade. 
         [0011]    U.S. Pat. No. 7,107,686 uses a latch cam with an offset pin onto which the coil spring is engaged. 
         [0012]    U.S. Publication 2005/0097754 has an activation rod connected between the coil spring and the blade. 
         [0013]    U.S. Pat. Nos. 7,086,157 and 7,146,736 use a cantilevered leaf spring that engages the blade while U.S. Pat. No. 7,146,736 has a secondary spring to lever lock the blade in open use position. 
         [0014]    A pair of torsion springs held axially on the blade can be seen in U.S. Pat. No. 7,748,122 pivotally rotating force engagement to the blade during activation. 
         [0015]    U.S. Pat. Nos. 7,293,360 and 7,562,454 both by the same inventor are directed to a pair of spring arms, one on each lateral side of the blade interconnected by a pin and roller sleeve. U.S. Pat. No. 7,676,932 discloses a folding knife having a spring with the blade to provide opening and closing force thereto. 
         [0016]    Finally, in U.S. Patent Publication 2007/0068002 a folding knife is disclosed with a selectively engageable opening mechanism having a spring engaged on one end in an aperture in the blade and the other in a travel slot in the handle. In U.S. Patent Publication 2009/0056146 A1 a knife spring mechanism is claimed having a pair of torsion springs on blade axis pin, with the blade having a pair of oppositely disposed thumb lugs to assist with opening and closing of the blade. 
       SUMMARY OF THE INVENTION 
       [0017]    A folding knife having a spring assist to fully open the blade from a closed “folded” retained position to an extended and locked position after initial user induced blade movement. A combination integral spring elements selectively engages a drive pin on the blade for initial rotation and release of the blade to an open extended position. A locking arm pivotally engaged and locks the blade open by spring biased engagement with the combination integral spring element. By pivotal engagement of the locking arm, the blade can be rotated under select and intermediate main spring engagement and compression to a closed retained locked position as hereinbefore described. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a side elevational view of the folding knife of the invention with portions broken away in open locked position. 
           [0019]      FIG. 2  is a partial top plan view of the folding knife in open locked position shown in  FIG. 1 . 
           [0020]      FIG. 3  is an enlarged partial side elevational view in closed locked position. 
           [0021]      FIG. 4  is an enlarged partial side elevational view of the assisted opening folding knife as it opens illustrated in broken and solid lines or progressively as it closes. 
           [0022]      FIG. 5  is a side elevational view of an alternate folding knife of the invention with portions broken away in open locked position. 
           [0023]      FIG. 5  is a side elevation view of an alternate folding knife of the invention with portions broken away in open locked position. 
           [0024]      FIG. 6  is a partial top plan view thereof. 
           [0025]      FIG. 7  is a side elevational view of the folding knife of  FIG. 5  in closed position. 
           [0026]      FIG. 8  is partial side elevational view of the alternate assisted opening folding knife as it opens and closes. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Referring to  FIGS. 1 and 2  of the drawings, an assisted opening knife  10  of the invention can be seen in the unfolded open lock position. The knife  10  has a handle portion  11  and a blade portion  12  pivotally secured thereto. The handle portion  11  has a support frame element  13  with a spring assist assembly  14  positioned therewithin. The blade portion  12  defines a blade  15  that is pivotally secured by a hinge pin  16  therethrough so as to be removably disposed within a blade retention slot RS so defined within the handle portion  11 . Accordingly, a sharpened blade edge  15 A on the blade  15  is safely enclosed therewithin as seen in  FIG. 3  of the drawings. 
         [0028]    The blade  15  has a shank portion  17  with an aperture at  18  through which the hinge pin  16  extends pivotally securing the blade  15  to the handle portion  11  as hereinbefore described. The shank portion  17  has a partial arcuate end edge  20  with a retainment receiving shank hook  21  and oppositely disposed blade stop notch  22  formed therein. The shank portion  17  also has a spring arm engageable deployment pin  23  extending therefrom in spaced relation to the blade hinge pin  16  and correspondingly blade back edge  24  as best seen in  FIG. 1  of the drawings. 
         [0029]    Referring now to the spring assist assembly  14 , it can be seen that it comprises a bifurcated spring arm element  25  secured within the handle portion  11  having a main blade engagement spring extension arm  26  and the bifurcated foreshortened locking bar engagement spring extension arm  27 . A pivoted locking bar  28  with a pivot pin  28 A is engaged by the spring arm  27  and has an oppositely disposed corresponding blade engagement notch free end portion  29  for selective engagement on the shank hook  21  when in unfolded locked position as again seen in  FIG. 1  of the drawings. 
         [0030]    The spring extension arm  26  correspondingly has a angled end edge corner surface  30  that is engaged against the upstanding deployment pin  23  as the blade  15  is rotated into the blade retainment slot RS in the handle portion  11  as seen in broken and solid lines in  FIG. 4  of the drawings. Correspondingly, the free end portion  29  of the locking bar  28  rests against the intermediate arcuate edge  20  on the shank portion  17  when so engaged. 
         [0031]    It will be evident from the above description that the spring extension arm  26  will be displaced under tension by the deployment pin  23  there against as the blade  15  is rotated into a closed position within the handle portion, thus preloading the blade for spring assist opening as will be described hereinafter. 
         [0032]    It can be seen that the associated geometry imparted by the blade hinge pin  16 , the so positioned deployment pin  23 , and registerable shank end surface  20  allows for the blade  15  assisted release and full open deployment in the following sequence under user&#39;s initial action. 
         [0033]    For assisted blade  15  deployment from the closed position, the user (not shown) engages oppositely disposed thumb lugs  31  indicated by force arrow F which extends from the back blade surface in spaced relation to the shank hook  29 , best seen in  FIG. 3  of the drawings. As noted, in the blade closed position, the edge corner surface  30  of the blade extension arm  26  is initially engaged on the deployment pin  23  under tension so that once the “user” initiates the hereinbefore described movement of the thumb lugs  31 , the blade  15  rotates as indicated by broken line directional arrows DA under spring tension. The engagement portion of the deployment pin  23  on the spring arm end edge corner  30  surface travels therealong driving the rotation of the knife blade  15  as seen from broken to solid lines in  FIG. 4  of the drawings. The rotational momentum imparted thereby propels the blade  15  to fully extended and locked position indicated at  32  as best seen in  FIG. 1  of the drawings. The blade  15  engages a blade stop pin  33  extending from the handle frame  13  in the shank stop notch  22  while the locking bar  28  free end  29  engages within the shank hook  21 . 
         [0034]    The locking bar  28  is, as noted, spring urged by the foreshortened spring arm  27  assuring a positive engagement as it travels around the arcuate end edge  20  of the shank portion  17  before locking engagement, as noted, within the shank hook portion  21 . 
         [0035]    It will be seen that by utilization of a bifurcated spring arm  25  which selectively engages with a geometrically and translaterly positioned deployment pin  23  on the shank portion  17  of the blade  15  will once the blade  17  is initiated by user be propelled outwardly from the handle portion by the spring urged rotation on the pivot hinge  16  to a fully open and locked position in longitudinal alignment with the handle portion  11  as seen in  FIG. 1  of the drawings. 
         [0036]    As hereinbefore described, the blade  15  will engage the blade stop pin  33  and the spring urged locking bar  28 &#39;s free end  29  will accordingly pivot into registration within the blade hook  21  locking the blade  17  in place. 
         [0037]    Referring now to  FIGS. 5 and 6  of the drawings, an alternate assisted opening knife  30  can be seen in unfolded open use locked position. The knife  30  has a handle  31  with a blade  32  pivotally secured thereto on a hinge pin  33 . The blade  32  has a shank portion  32 A with an arcuate end engagement edge  33  with a shank hook  34  and oppositely disposed blade stop notch  35  therein, as hereinbefore described in the primary form of the invention of the knife  10 . 
         [0038]    An alternate modified spring assist assembly  36  is mounted within the handle  31  by multiple fasteners F and has corresponding duel interconnected spring arms  37 A and  37 B. The spring arm  37 A has an end corner angle blade engagement surface  38  that is selectively engaged on an upstanding blade deployment pin  39 , which extends from the shank portion  32 A of the blade  32  when going from a pivotally open position shown in  FIG. 8  to a fully closed position as seen in  FIG. 7  of the drawings. 
         [0039]    A pivoted blade locking bar  40  is mounted within the handle  31  on a pivot pin  41  and has a upstanding spring engagement pin  42  positioned midway between the pivot pin  41  and its end at  43 , which is in constant spring urge contact with the spring arm  37 B as seen in  FIG. 7  of the drawings in closed blade position to fully opened blade position, shown in  FIG. 5  of the drawings. 
         [0040]    The blade locking bar  40  has a tapered blade engagement end  40 A defining a tab  40 B extending therefrom that is selectively engaged within the shank hook  34  when the blade  32  is in open locked position as illustrated. 
         [0041]    In operation, to release the blade  32  from the lock open position, the locking bar  40  is depressed (see force arrow FA) by user (not shown) against the spring arm  32  pivoting blade engagement tab  40 B upwardly out of registration within the shank hook  34  engagement. 
         [0042]    Once released, the blade  32  is then rotated to close position in the handle  31  with the shank deployment pin  39  engaging the spring arm  32 A which will be displaced under tension as the blade is closed within the handle  31 , thereby preloading the blade  32  for a spring urged assist during opening, as will be described hereinafter. 
         [0043]    As noted, for assisted blade  32  deployment from the blade closed spring balance position, the user (not shown) engages one of the oppositely disposed thumb lugs  42  which extend in oppositely disposed relation from the blade in space relation to the shank hook, as best seen in  FIG. 7  of the drawings. Given that in the blade closed position the edge corner surface  38  of the spring arm  37 A is initially engaged on the shank deployment pin  39  under balance tension, so once opening is initiated by user engagement of the hereinbefore described thumb lugs  42 , the spring arm  32 A will drive the blade  32  outwardly to a point of pin arm release  39 , seen in  FIG. 8  of the drawings, propelling the blade to full locking extended position as seen in  FIG. 5  of the drawings. 
         [0044]    It will be evident that when fully deployed, the blade  32  will be automatically locked in place by the spring engagement of the hereinbefore described locking bar end tab  40 B within the shank hook  34  as noted.