Pocket knife with wedge lock

Abstract: A wedge-shaped arrangement (50) for retracting a leaf spring (72) is positioned in abutment against the tang (76) of a cutting knife (10). The retraction of the leaf spring (72) is produced by a sliding rod (58) which engages the wedge (60) and pulls on the leaf spring (12) out of engagement with the tang.

Description: The present invention is directed to a pocket knife comprising a lock for barring a blade and more particularly to a wedge and leaf spring arrangement for locking and unlocking the blade in its protracted position. A search of the prior art has revealed three U.S. Patents, Nos 2,183,378; 2,826,813 and 4,354,313 and one German document, No. 1,062,146. In the document US 2,183,378 the main purpose of the leaf spring is to maintain the lever and the push button in the upper position. The leaf spring does not have any direct locking action on the blade. Moreover, this embodiment does not include a guiding means allowing the blade to be protracted and retracted with one hand. It also comprises many moving parts, bringing about a complex design and assembly. In the document DE-1,062,146, against which the subject-matter of the independent claims is delimited, the described device includes a spring so as to allow an automatic protracting motion of the cutting blade instead of a guiding means for manual protraction as in the invention. According to the present invention, the blade of a pocket knife is locked in its protracted position and it is possible to pull out and retract it manually, with one hand, by using a guiding means. There is therefore no need to touch the blade. Some governments make it illegal to have a pocket knife whose blade opens automatically, by gravity or by inertia; the present device is easy to operate, it is completely legal in this regard, it is safer to use and therefore entails less risk for the user than the pocket knife of the prior art. The simplified wedge arrangement proposed for locking the blade allows the pocket knife to remain thin and compact. The lock for barring a cutting blade of a pocket knife comprises a leaf spring which is adapted to abut at one end with the tang of the blade to maintain the latter in this protracted position. The plane of the leaf spring is retracted from the plane of the blade by a wedge arrangement which consequently allows the blade to be retracted in its closed position. Figure 1 is a plan view of a pocket knife according to the invention with the blade in its protracted position, Figure 2 is a plan view of the side opposite the one shown in figure 1 with the blade in its retracted position, Figure 3 is an exploded view of the knife shown in figure 2, Figure 4 is a cross-sectional view of the wedge action as shown in figure 4 with the tongue of a leaf spring in a released position, Figure 5 is a cross-sectional view of the wedge action with the tongue in a retracted position, Figure 6 is a plan view of the pocket knife according to another embodiment of the invention with the blade in its protracted position, Figure 7 is a bottom view of the knife shown in figure 6 and, Figures 8 and 9 are detailed views of the lock mechanism according to the embodiment shown in figure 6, Figure 10 is a perspective view of another embodiment of a wedge action lock, Figure 11 is a plan view of a further embodiment of a pocket knife according to the invention, Figure 12 is a bottom view of the knife according to figure 11, Figure 13 is a plan view of the last shown embodiment of a pocket knife according to the invention, and Figure 14 is a bottom view of the knife according to figure 13. Referring to figures 1 to 5, reference character 10 generally indicates a blade-knife having a wedge type lock 12 and comprising an elongated casing 13 formed by an upper face plate 14 and a lower face plate 16 and a retractable blade 20. The lower face 16 is provided with a groove 18 which serves as guiding means for the sliding movement of blade 20 indicated in figure 3 by arrows 24. This sliding movement of the blade 20 is produced by pressure exerted on a button 26 by the user's finger. The pressure is transmitted to blade 20 by means of a screw type component 28 which is threadedly inserted in aperture 30 in the tang 31 and slides inside slot 32 provided in the lower face plate 16. An elongated recess 34 in the face plate 16 is used to guide the sliding action of a stabilizing element 36 slidingly mounted on screw 28. The stabilizing element 36 is used to reduce the stress concentration between the screw 28 and the extremities of the slot 32 when the blade is pushed at both outermost positions as shown in figures 1 and 2. Element 36 also stabilizes the upright position of the screw type component 28. The stress concentration reducing effect is imputable to the larger radius of material of the element 36 on which the force is applied around the recess 34. The upper face plate 14 is provided with a groove 38 adapted to guide the sliding action of a sliding member 40. A leaf spring 42 is also inserted in the upper face plate 14 inside a groove 44. Leaf spring 42 is used in conjunction with sliding member 40 to provide releasable locking action on blade 20. Leaf spring 42 consists of a piece of resilient material which has a centrally punched longitudinal tongue 46 surrounded by a contour plate 48. The tongue is bent relative to the contour plate 48 at an angle which allows the tip 74 of the tongue 46 to exceed outside the plane of the plate 48. A wedge shaped component 50 is rigidly secured to the top of the tongue 46. Sliding member 40 comprises a base plate 52 to which is rigidly attached a knob 54 which extends through aperture 55 provided in the upper face plate 14. Base plate 52 is U-shaped in order to provide a spacing 56 adapted to receive the wedge-shaped component 50. A small rod 58 extends transversally from the longitudinal sides of spacing 56. Rod 58 is used in conjonction with the wedge-shaped component 50 to lift the tongue 46 so as to make tongue 46 coplanar with the contour plate 48 as illustrated in figure 5. When the sliding of the sliding member 40 is produced by a pressure of the user's thumb on knob 54, rod 58 which is rigidly attached to base 52 slides against inclined surface 60 of wedge-shaped component 50, therefore lifting tongue 46 as illustrated in figures 4 and 5. The inclined surface 60 defines an acute angled space between the tongue 46 and the wedge-shaped component 50. The top surface of the knob 54 is preferably slightly inclined and provided with grooves which make the surface rugose in order to facilitate transformation of the pressure applied by the thumb of the user into sliding motion of sliding member 40 in groove 38. An helicoidal spring 62 or another suitable device is positioned inside an extension 64 of the groove 38. One extremity of spring 62 rests against surface 66 of the extension 64 while the other end rests against surface 68 of the sliding member 40 so that the spring is compressed when rod 58 slides along surface 60 and bounces back when pressure by the user's thumb is released from the knob 54. The upper face plate 14 and lower face plate 16 forming the outer elongated casing 13 are held together by screw-type components 70. The blade 20 is protracted out of casing 13 by applying pressure on button 26 which slides the blade in groove 18. Once the cutting edge portion 61 of the blade is fully protracted out, no more pressure is applied, by the blade 20, on back surface 72 of the tongue 46 which automatically assumes its released position illustrated in figure 4. In that released position, front surface 74 of tongue 46 is directly in contact with back surface 76 of tang 31 therefore inhibiting retraction of the blade inside casing 13 and accordingly barring the blade. To retract blade 20 inside casing 13, the user's thumb applies pressure in the direction of the pointed end of the blade on knob 54 of lifting component 40 which as stated previously will lift tongue 46 until it becomes coplanar with the contour plate 48. The user's index can then apply pressure on button 26 and retract the blade 20. To avoid jamming of tongue 46 while initiating the retraction of the blade or a full protraction of it, both surfaces 74 and 76 are preferably chamfered on opposite sides at an angle C of about 3° to 5°. In this embodiment, it is particularly easy to retract the blade inside its casing with one hand. Because the knob 54 and the button 26 are located at remote distances and on opposite sides of the knife, it is possible to simultaneously slide them in opposite direction with the thumb and the index of the same hand. It is within the embodiment of this invention to substitute other wedge type action locks for the ones described above. Figure 10 illustrates an alternative to the wedge type lock 12 wherein a shank 120 fixed to a leaf spring 121 can be lifted by a split wedge plate 122 which corresponds to the sliding member 40. When the wedge plate 122 slides in the direction of the arrow 124, the U-shaped notch 126 engages the nail type component and raises the leaf spring 121. Figures 6 to 9 illustrate another embodiment of the invention again using a wedge-type lock adaped for a knife having a blade which protracts from the handle by a pivoting action rather than a sliding action as was the case with the previously described embodiment. In this embodiment of the invention, a rod 82 forming part of a sliding member 84 is rigidly attached to the side of the sliding member 84 which slides in a groove 88 provided in a superposed casing 90. The sliding of the member 84 is indicated in figures 8 and 9 by an arrow 92. A leaf spring 94 is located like face plate or a bolster lining against the upper face of the casing 90 and over the space 96 designed to receive the retracted blade 102. The leaf spring 94 is made of a piece of resilient material from which a lateral tongue 98 is longitudinally punched. The tonge 98 projects away from the plane of the main strip 100 of leaf spring 94 by an angle sufficient to displace the tip surface 108 of the tongue 98 below and adjacent the plane of the main strip 100 of the spring 94. In use, when blade 102 is fully protracted by a pivoting action around a hinge 104, rip surface 108 of the tongue 98 abuts against the end surface 110 of tang 112 and accordingly the pivoting of the blade 102 is barred. To allow the pivotal retraction of blade 102 inside the casing 90, the user must apply pressure on the knob 114 of sliding member 84 in roder to induce a sliding movement which will cause rod 82 to slide against inner surface 116 of wedge-shaped component 118. The wedge-shaped component 118 being rigidly attached to the tongue 98, the latter is pulled by the rod 82 so that it reaches the same plane as the one of the main strip 100 as in figure 9. Once the tongue 98 is coplanar with strip 100, end surfaces 108 and 110 are no longer in contact and the blade 102 is free to rotate around the hinge 104. When pressure is released from the knob 114, a small helicoidal spring 113 brings the lifting component 84 to its original position such as shown in figure 9. The wedge action takes place along the lateral portion of the leaf spring 94 in figures 6-9 while it is centrally located in figures 1-5. Figures 11 and 12 show a further embodiment of a pocket knife which substantially corresponds to that of figure 1 but is of simpler construction. A button 127 pivotingly connected to the rearward end of the blade by means of an arbor 128 perpendicular to the blade axis and parallel to the plane of the flat surface, has a nose 129. The leaf spring (130) rests against the rearward end of the blade of the knife and prevents the blade from being pushed in. By twisting the button 127, the nose 129 presses on the leaf spring 130 and thereby releases the blade. The blade can now be sunk into the knife with the aid of the button 127. In this exemplified embodiment, the leaf spring 130 is, as figure 12 clearly shows, disposed substantially parallel to the blade in the interior of the casing of the knife. Figures 13 and 14 show a last exemplified embodiment of a pocket knife according to the invention. The knife roughly corresponds to that of figures 11 and 12. Instead of a leaf spring 130 inserted into the casing, a leaf spring 131 is incorporated in a half of the casing. The half-casing having the leaf spring 131 is made in one piece and has a U-shaped, slot-like groove consisting of the base leg 134 and the two legs 132, 133. The leaf spring 131 thereby exposed is subsequently biased in such a way that when the blade of the knife is extended, it engages the rearward end of the blade, as already described in the preceding exemple. The leaf spring is releasable from the rearward end of the blade by means of the button 127 and the nose 129, and the blade can be pushed into the inside of the knife, with the aid of button 127. A loading ball bearing 136 falls into a hole 135 in the blade tang to prevent the blade from coming out of the handle by itself.

Claims: A pocket knife (10) comprising an elongated casing having an upper and a lower face plate (14, 16) and a longitudinal space (18) between the two face plates, a cutting blade (20) moveable between a protracted and a retracted position extending in said space, a lock (12) for barring and unbarring said cutting blade (20) in its protracted forwardly projected position, said blade having a cutting edge portion (61) and a tang (31) in a flat plane, said lock comprising a substantially flat leaf spring (42) extending in a plane substantially parallel to said blade (20), said leaf spring (42) having a tongue (46) slightly bent away from said parallel plane so as to abut against the tang (31) of said blade (20) for maintaining the cutting blade in its forwardly projected position, wedge means (50) for retracting the said tongue (46) of the said spring (42) into said parallel plane so as to bring said tongue (46) of said leaf spring (42) away from the flat plane of said tang (31) and allow freedom of movement of said blade, characterized in that the pocket knife comprises guide means (26, 28) on said lower face plate (16) extending through a slot (32) provided in said lower face plate and secured to one end of said blade (20), said guide means (26, 28) being adapted to slide said blade in said space (18) and to project part of it outside the casing (14, 16) to an outermost position. A pocket knife as recited in claim 1, characterized in that said leaf spring (42) is partly split in two longitudinal strips, one of these strips forming a tongue (46) being curved so that the end (74) of said tongue abuts against the tang (31) of the blade (20) in a plane different than the plane of the other strip (48), said wedge means comprising a wedge member (50) secured to said tongue (46) and defining an acute angled recess between said tongue and said wedge member, a sliding member (40) mounted on the other strip (48) and adapted to longitudinally move relative to said tongue (46), said sliding member (40) comprising a rod member (58) secured to said sliding member, said rod member (58) being mounted on said sliding member (40) so as to slide in said angular space and apply pressure on said wedge member (50) for changing the curve of said tongue (46) and for removing the end (74) of said tongue from abutting the tang (31) of the blade. A pocket knife as recited in claim 2, characterized in that the sliding member (40) is resiliently biased in a direction to retract said rod member (58) from said angular recess. A pocket knife as recited in claim 3, characterized in that the two strips (46, 48) are mounted side by side in about the same plane and longitudinally fixed relative to each other. A pocket knife (10) comprising an elongated casing having an upper and a lower face plate (14, 16) and a longitudinal space (18) between the two face plates, a cutting blade (20) moveable between a protracted and a retracted position extending in said space, a lock (12) for barring and unbarring said cutting blade (20) in its protracted forwardly projected position, the said blade having a cutting edge portion (61) and a tang (31) in a flat plane, said lock comprising a shank (120) secured to said leaf spring (121) and an enlarged head at the end of said shank, an intermediate lining located adjacent said leaf spring, characterised by wedge plate (122) slidingly mounted on said intermediate lining, said wedge plate having a slot (126) adapted to engage said shank and pull on said leaf and said leaf spring (121) during its sliding movement for freeing the tang (31) of said blade (20), and by guide means (26, 28) on said lower face plate (16) extending through a slot (32) provided in said lower face plate and secured to one end of said blade (20), said guide means (26, 28) being adapted to slide said blade in said space (18) and to project part of it outside the casing (14, 16) to an outermost position. A pocket knife comprising a lock for barring and unbarring a cutting blade (102), a superposed casing (90) defining a space (96) therebetween, a cutting blade (102) mounted in said space, said blade having a cutting edge portion and a tang (112) in a flat plane, said lock comprising a leaf spring (94) fixed to the casing in said space, a wedge member (118) secured to said leaf spring, the wedge member defining an acute angled recess between said leaf spring and said wedge member, characterized in that said cutting blade (102) is pivotable around a hinge (104) , one end (98) of said leaf spring is adapted to abut against the end surface (110) of said tang (112) when the blade is fully protracted, a sliding member (84) is mounted in a groove (88) provided in said casing (90) and adapted to longitudinally move relative to said wedge member (118), the sliding member (84) comprises a rod member (82) adapted to slide in said angular recess of the wedge member (118) so as to pull on said leaf spring (94) and retract latter from abutment with the end surface (110) of the tang (112), and in that spring means (113) is provided for resiliently pushing said rod member out of said angular recess. A pocket knife as recited in claim 6, characterized in that it comprises a first knob (114) extending out of a slot provided through said casing, said sliding member (84) extending out of the slot in said casing and at the distal end from the end (108) of said blade (102) when said blade is in its retracted position, wherein a movement of the said knob and said sliding member simultaneously projects said blade (102) out of said casing (90) and causes said abutment with the leaf spring (94). A pocket knife comprising a lock for barring and unbarring a cutting blade (102) it its forwardly projected position, a superposed casing (90) defining a space (96) therebetween, a cutting blade (102) having a cutting edge portion slidably mounted in said space relative to one side of said casing and adjacent thereto, said lock comprising a leaf spring (130) fixed to the other side of casing in said space (96) , one end of said leaf spring (130) adapted to abut against the end of said blade (102) when the latter is fully projected forwardly out of said casing (90), a button (127) protruding out of a slot provided through said first side of said casing, said slot extending along the length of said casing, characterized in that said button (127) is pivotingly connected to the rearward end of said blade by means of an arbor (128) perpendicular to the blade axis, and parallel to the plane of the flat surface, and is adapted to press on said leaf spring to retract the latter from abutment with the end of the blade, allowing free motion of the blade in and out of the casing with the aid of said button (127) sliding in said slot. A pocket knife as recited in claim 8, characterized in that said leaf spring (131) is incorporated in said other side of casing.

Inventors: LEMAIRE DENIS J, LEMAIRE, DENIS J.
Applicants: WENGER SA, WENGER S.A.
Application year: 1989
Main classification: B26B1
IPC codes: B26B1