looking first at fig1 - 4 , there is shown novel endoscopic cutting forceps 5 which comprise one preferred embodiment of the present invention . endoscopic cutting forceps 5 generally comprise a pair of jaws 10 disposed at the distal end of a shaft 15 , a blade cutter 20 configured to reciprocate in the space between jaws 10 ( and hence cut tissue disposed between the pair of jaws ), and a handle 25 disposed at the proximal end of shaft 15 for carrying a lever 30 for actuating the pair of jaws 10 and a trigger 35 for actuating blade cutter 20 . endoscopic cutting forceps 5 preferably allow the pair of jaws 10 and blade cutter 20 to be rotated as a unit about the axis of shaft 15 via a knob 40 , and endoscopic cutting forceps 5 preferably allow the pair of jaws 10 to be electrically energized via a button 45 so as to provide electrocautery function to endoscopic cutting forceps 5 . more particularly , and looking now at fig1 - 9 , jaws 10 are each secured to the distal end 50 of a support rod 55 , with support rods 55 and the proximal ends of jaws 10 being disposed within shaft 15 . the proximal ends 60 of support rods 55 are secured to a hub 65 , which is itself secured to a wall 70 of handle 25 . as a result of this construction , jaws 10 are effectively fixed to handle 25 . as seen in the figures , jaws 10 are outwardly biased relative to support rods 55 , so that the distal ends of jaws 10 naturally diverge from one another . jaws 10 comprise slots 75 ( fig4 ) which receive blade cutter 20 . shaft 15 is movable relative to handle 25 so as to selectively close down jaws 10 . more particularly , shaft 15 is hollow and is disposed coaxially over the proximal ends of jaws 10 and coaxially over support rods 55 . the proximal end of shaft 15 is connected to a mount 80 ( fig6 ) which is engaged by lever 30 as will hereinafter be discussed . shaft 15 has a flange 85 intermediate its length . a compression spring 90 is disposed about shaft 15 between a wall 95 of handle 25 and flange 85 of shaft 15 so as to spring - bias shaft 15 in the proximal direction . another compression spring 100 may be disposed about shaft 15 between flange 85 of shaft 15 and a surface of mount 80 so as to bias mount 80 proximally . as noted above , lever 30 may be used to actuate jaws 10 . more particularly , lever 30 is rotatably pinned at 105 to handle 25 so that when the finger grip 110 of lever 30 is pulled proximally toward palm grip 115 of handle 25 , the opposing end 120 of lever 30 is moved distally , whereby to move mount 80 distally and thereby move shaft 15 distally . such distal movement of shaft 15 forces jaws 10 to close . when finger grip 110 of lever 30 is released , compression spring 90 returns shaft 15 proximally , whereby to cause jaws 10 to open . note that blade cutter 20 is received in slots 75 of jaws 10 when jaws 10 are in their open position and blade cutter 20 is also received in slots 75 of jaws 10 when jaws 10 are in their closed position . looking now at fig1 - 8 , 10 and 11 , blade cutter 20 is disposed at the distal end 125 of a drive rod 130 , with the proximal end of blade cutter 20 and drive rod 130 being disposed within shaft 15 . the proximal end of drive rod 130 is secured to a hub 135 . trigger 35 actuates blade cutter 20 . more particularly , trigger 35 is rotatably pinned at 140 to handle 25 so that when trigger 35 is pulled proximally toward palm grip 115 of handle 25 , the opposing end 145 of trigger 35 is moved distally , whereby to move hub 135 distally and thereby move drive rod 130 and blade cutter 20 distally . note that when jaws 10 are in their closed position and blade cutter 20 is moved distally , blade cutter 20 will ride distally within slots 75 formed in jaws 10 . as noted above , endoscopic cutting forceps 5 preferably allow the pair of jaws 10 and blade cutter 20 to be rotated as a unit about the axis of shaft 15 via a knob 40 . to this end , knob 40 drivingly engages mount 80 such that when knob 40 is rotated , mount 80 is also rotated , whereby to rotate hub 65 and thereby rotate support rods 55 and hence jaws 10 . note that inasmuch as blade cutter 20 is received within slots 75 in jaws 10 when jaws 10 are in both their open and closed positions , rotation of jaws 10 will cause blade cutter 20 to rotate in unison with jaws 10 . as also noted above , endoscopic cutting forceps 5 allow the pair of jaws 10 to be electrically energized via a button 45 so as to provide electrocautery function to endoscopic cutting forceps 5 . more particularly , and looking now at fig1 - 3 , 5 - 9 and 12 - 16 , in the preferred form of the invention , jaws 10 and support rods 55 are formed out of an electrically conductive material , and button 45 is used to activate a switch which connects a power line 150 to jaws 10 . as a result , pressing button 45 electrically energizes jaws 10 so as to provide electrocautery function to endoscopic cutting forceps 5 . in this respect it should be appreciated that , where shaft 15 is made out of an electrically conductive material , and / or where drive rod 130 is made out of an electrically conductive material , an insulating member 155 is disposed between shaft 15 and support rods 55 and jaws 10 , and between drive rod 130 and support rods 55 and jaws 10 , so as to avoid inadvertent short - circuiting of the electrical components of endoscopic cutting forceps 5 . thus it will be seen that endoscopic cutting forceps 5 generally comprise a pair of jaws 10 disposed at the distal end of a shaft 15 , a blade cutter 20 configured to reciprocate in the space between jaws 10 ( and hence cut tissue disposed between the pair of jaws 10 ), and a handle 25 disposed at the proximal end of shaft 15 for carrying a lever 30 for actuating the pair of jaws 10 and a trigger 35 for actuating blade cutter 20 . endoscopic cutting forceps 5 preferably allow the pair of jaws 10 and blade cutter 20 to be rotated as a unit about the axis of shaft 15 via a knob 40 , and endoscopic cutting forceps 5 preferably allow the pair of jaws 10 to be electrically energized via a button 45 so as to provide electrocautery function to endoscopic cutting forceps 5 . in accordance with the present invention , there is also provided a novel latching mechanism for the lever which actuates the jaws , whereby to allow the jaws to be temporarily locked ( or clamped ) in a closed position about tissue while the blade cutter is actuated to cut the tissue disposed between the clamped jaws . significantly , the latching mechanism of the present invention is mechanically simple and hence easy and inexpensive to manufacture . in addition , the latching mechanism of the present invention may also be used for the actuating levers of other surgical instruments and / or other lever - actuated devices wherein the latching mechanism is mechanically simple and hence easy and inexpensive to manufacture . looking next at fig1 - 3 , 5 - 7 , 9 - 11 and 17 - 26 , there is shown a latching mechanism 200 which comprises one preferred form of the present invention . latching mechanism 200 generally comprises a selector plate 205 and a latch plate 210 . selector plate 205 serves to selectively position latch plate 210 within handle 25 . selector plate 205 is movably mounted to handle 25 , and latch plate 210 is mounted to selector plate 205 , such that , by adjusting the position of support plate 205 within handle 25 , the position of latch plate 210 may also be adjusted within handle 25 . in this way selector plate 205 can be used to selectively position latch plate 210 in a “ latch operative position ” or in a “ latch inoperative position ” within handle 25 , as will hereinafter be discussed . more particularly , selector plate 205 is slidably mounted to handle 25 of endoscopic cutting forceps 5 . a thumb button 215 protrudes through a window 220 formed in handle 25 so that the user can adjustably position selector plate 205 ( and hence adjustably position latch plate 210 ) within handle 25 . detents 225 are formed in selector plate 205 and cooperate with a protrusion 230 formed on handle 25 whereby to allow selector plate 225 to be maintained in a “ latch operative position ” or in a “ latch inoperative position ” within handle 25 until urged otherwise by the user . latch plate 210 is slidably mounted to selector plate 205 . more particularly , latch plate 210 comprises a body 235 having a loop spring 240 extending therefrom ( fig2 ). in one preferred form of the invention , loop spring 240 is formed integral with body 235 . loop spring 240 comprises a bore 245 which is mounted on a pin 250 of selector plate 205 . loop spring 240 biases body 235 of latch plate 210 into a given position on selector plate 205 , but permits body 235 of latch plate 210 to be slidably moved on selector plate 205 ( both towards and away from pin 250 on selector plate 205 ) against the power of loop spring 240 . in one preferred form of the invention , latch plate 210 moves linearly with respect to handle 25 as latch plate 210 moves on selector plate 205 . body 235 of latch plate 210 includes a flange 257 which is slidably mounted on selector plate 205 , whereby to stabilize latch plate 210 as it moves on selector plate 205 . as a result of this construction , body 235 of latch plate 210 can be urged away from pin 250 of selector plate 205 against the power of loop spring 240 , or body 235 of latch plate 210 can be urged toward pin 250 of selector plate 205 against the power of loop spring 240 . a latch element 255 is mounted to body 235 of latch plate 210 . in one preferred form of the invention , latch element 255 is formed integral with body 235 of latch plate 210 . latch element 255 comprises a first surface 260 , a second surface 265 , and a third surface 270 ( fig2 ). in one preferred form of the invention , first surface 260 comprises a substantially linear configuration , second surface 265 comprises a concave configuration , and third surface 270 comprises a slightly convex or substantially linear configuration . first surface 260 , second surface 265 and third surface 270 together define a labyrinth ( i . e ., a non - linear track comprising a leading first surface 260 , a concave second surface 265 , and a trailing third surface 270 , whereby to form a tortuous path with a concavity intermediate its length ), and interact with a latch pin 275 ( fig2 ) formed on lever 30 , so as to provide the desired latching function . more particularly , when selector plate 205 is appropriately positioned within handle 25 so that the apparatus is configured in the “ latch operative position ”, and when lever 30 is thereafter pulled toward palm grip 115 of handle 25 ( i . e ., so as to close jaws 10 ), latch pin 275 engages first surface 260 of latch element 255 and forces latch plate 210 away from pin 250 , against the power of loop spring 240 . latch pin 275 rides along first surface 260 of latch element 255 until latch pin 275 reaches the end of first surface 260 , whereupon latch pin 275 moves onto second surface 265 of latch element 255 . as soon as latch pin 275 moves onto the concave second surface 265 , loop spring 240 pulls body 235 of latch plate 210 back toward pin 250 , until latch pin 275 seats at the base of concave second surface 265 . at this point , lever 30 will be maintained in this position ( i . e ., the “ latched ” position , with jaws 10 clamped ) until lever 30 is thereafter pulled again . more particularly , when it is thereafter desired to unclamp jaws 10 , lever 30 is pulled again , against the power of loop spring 240 , so as to cause latch pin 275 to move out of the base of concave second surface 265 of latch element 255 and further along concave second surface 265 . as soon as latch pin 275 clears the end of concave second surface 265 and moves onto third surface 270 of latch element 255 , loop spring 240 pulls latch plate 210 back toward pin 250 , until latch pin 275 is returned to its original starting position clear of third surface 270 . at this point , lever 30 will have been returned to its original starting position , pending a further cycling of endoscopic cutting forceps 5 . it will be appreciated that the latching function just described relies upon the interaction of latch pin 275 with latch element 255 . it will also be appreciated that selector plate 205 allows the position of latch plate 210 to be adjusted within handle 25 . thus selector plate 205 provides the ability to render the latching function operative or inoperative by adjusting the position of latch plate 210 ( and hence the position of latch element 255 ) vis - à - vis the position of lever 30 ( and hence the orbit of latch pin 275 ). more particularly , by positioning selector plate 205 so that the position of latch element 255 is outside the orbit of latch pin 275 , the selector plate can be used to put the apparatus in a “ latch inoperative position ”. conversely , by positioning selector plate 205 so that the position of latch element 255 is within the orbit of latch pin 275 , the selector plate can be used to put the apparatus in a “ latch operative position ”. the user adjusts the position of selector plate 205 using thumb button 215 . fig2 - 38 illustrate operation of the endoscopic cutting forceps 5 ( note that the specific constructions shown in fig2 - 38 may differ slightly from the specific constructions shown in fig1 - 26 , however , fig2 - 38 depict a common operation of the latching function of the present invention ). more particularly , fig2 - 35 show endoscopic cutting forceps 5 with selector plate 205 set in the “ latch operative position ” and with the apparatus cycling through a complete latching / unlatching operation . fig3 - 38 show endoscopic cutting forceps 5 with selector plate 205 set in the “ latch inoperative position ” and with lever 30 cycling through a complete “ pull and release ” operation . in the preceding description , lever 30 is described as being rotatably pinned to handle 25 at 105 . however , it should be appreciated that other connections may also be employed . by way of example but not limitation , lever 30 may be movably mounted to handle 25 by the legs of a so - called “ 4 - bar ” mechanism . it should be appreciated that , if desired , selector plate 205 may move in a direction which is different than the direction of movement of latch plate 210 , provided , however , that movement of selector plate 205 moves latch plate 210 into , and out of , the orbit of latch pin 275 . by way of example but not limitation , selector plate 205 could move in a direction perpendicular to the direction of movement of latch plate 210 , whereby to move latch plate 210 into , and out of , the orbit of latch pin 275 . if desired , latch plate 210 may be movably mounted to selector plate 205 by a variety of means , so as to provide a variety of different movements , e . g ., linear movement , pivoting movement , prescribed motion such as by a so - called “ 4 - bar ” mechanism , traversing in an arcuate track , etc . thus it will be seen that the present invention provides a new and improved latching mechanism for an endoscopic cutting forceps wherein the latching mechanism is mechanically simple and hence easy and inexpensive to manufacture . it will also be appreciated that the new and improved latching mechanism of the present invention may be used in conjunction with the actuating levers of other surgical instruments and / or other lever - actuated devices , whereby to provide a latching mechanism which is mechanically simple and hence easy and inexpensive to manufacture . it will be appreciated that various modifications may be made to the preferred embodiments discussed above without departing from the scope of the present invention . thus , for example , the locations of selector plate 205 / latch plate 210 and latch pin 275 may be reversed , i . e ., selector plate 205 and latch plate 210 may be mounted on lever 30 and latch pin 275 may be mounted on handle 25 . by way of further example but not limitation , selector plate 205 may be omitted , in which case latch plate 210 is slidably mounted directly to handle 25 ( or , if the location of latch plate 210 and latch pin 275 are reversed , slidably mounted directly to lever 30 ). of course , in this form of the invention , the apparatus is always set in the “ latch operative position ” and is incapable of being set in the “ latch inoperative position ”. it should be understood that many additional changes in the details , materials , steps and arrangements of parts , which have been herein described and illustrated in order to explain the nature of the present invention , may be made by those skilled in the art while still remaining within the principles and scope of the invention .
a lever latching system comprising : a housing ; a lever having a latch pin fixedly mounted to the lever , the lever being movably mounted to the housing so that the latch pin moves in an arc ; and a latch plate movably mounted to the housing for linear movement with respect to the housing , the latch plate comprising a labyrinth for receiving the latch pin .