embodiments of the presently disclosed stapler will now be described in detail with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views . as is common , the term ‘ proximal ” refers to that part or component closer to the user or operator , i . e . surgeon or physician , while the term “ distal ” refers to that part or component further away from the user . fig1 illustrates one type of surgical stapler that can incorporate the cam bar / pusher arrangement of the present disclosure . the surgical stapler 10 has a cartridge half section 12 , an anvil half section 14 , and handles 15 and 16 for facilitating clamping of the sections 12 and 14 . cartridge half section 12 has a channel 47 ( fig2 ) to receive cartridge 32 which includes a plurality of staples 60 and a plurality of staple pushers 36 to advance the staples 60 from the cartridge 32 through slots 52 . the staple firing mechanism includes a cam bar assembly which is advanced by distal advancement of manual firing lever 28 ( fig1 ). the cam bar assembly is slidable for longitudinal advancement in the cartridge 32 to advance the pushers 36 in a direction substantially transverse to the longitudinal axis of the stapler and substantially transverse to the direction of movement of the camming members . engagement of the pushers 36 by the cam members advances the staples 60 through the tissue and into contact with the anvil depressions ( pockets ) 22 ( fig5 ) of the anvil half section 14 . in the illustrated embodiment of fig2 , there are two staggered linear rows of staple slots 52 formed on either side of a knife slot 58 which guides a knife bar 50 with knife blade 51 between the rows of staples 60 . a different number of rows can be provided and a knife can optionally not be provided . a single staple 60 is positioned in each of the slots 52 . staple pushers 36 are aligned with each slot 52 so that preferably a single staple pusher 36 is positioned under the staple 60 retained in the slot 52 . the pushers 36 can optionally be attached to each other in groups of two offset oriented pusher pairs . more details of the stapler are disclosed in u . s . pat . no . 7 , 140 , 527 , issued nov . 28 , 2006 , and u . s . pat . no . 7 , 055 , 730 , issued jan . 6 , 2006 , the entire contents of each of these applications are incorporated herein by reference . with reference to fig2 and 3 , the cam member arrangement of the present disclosure will now be described . cam member support or sled 38 includes a pair of outer camming elements 39 a and a pair of inner camming elements 39 b . an upper pair of projecting ribs or teeth 56 a ( only one of which is shown in the view of fig3 ) are positioned on opposing sides of the support 38 . a lower pair of ribs or teeth 56 b ( only one of which is shown in the view of fig3 ) are positioned on opposing sides of the support 38 . the outer camming elements 39 a and inner camming elements 39 b are preferably axially staggered as shown , i . e . the inner camming elements 39 b are positioned slightly distally of outer camming elements 39 a . cam adjusting members 34 and 35 extend through slots 54 a 54 b , respectively in cartridge 32 and are biased upwardly ( toward tissue contacting surface 33 of cartridge 32 ) by springs 36 a , 36 b and 37 a , 37 b , respectively . cam adjusting member 35 has a projecting tab 35 a at a proximal end engageable with pivot arm 48 . cam adjusting member 34 has a projecting tab 34 a at a proximal end for engagement with pivot arm 42 . the opposite surface ( upper surface as viewed in the orientation of fig2 ) of cam adjusting member 35 has a tissue contacting surface 35 b with an extended planar surface forming a t - shape . similarly , the opposite surface of cam adjusting member 34 has a tissue contacting surface 34 b forming a t - shape . the surfaces 34 b , 35 b come into contact with and compress the tissue when the anvil and cartridge sections 14 , 12 are approximated to clamp tissue therebetween . the cam adjusting members 34 , 35 adjust in the distance they protrude from the slots 54 a , 54 b , depending on tissue thickness . this can be seen for example by comparing fig5 , 10 and 13 . when the tissue is relatively thin as shown in fig5 , the cam adjusting members 34 , 35 will protrude a distance x beyond the tissue contacting surface 33 of cartridge 32 . when encountering thicker tissue clamped between the cartridge and anvil sections 12 , 14 as in fig1 , the cam adjusting members 34 , 35 will protrude a shorter distance y from the tissue contacting surface 33 of the cartridge 32 . in fig1 , even thicker tissue is encountered such that the cam adjusting members 34 , 35 barely protrude from the slots 54 a , 54 b as the t - surfaces 34 b , 35 b are positioned on the tissue contacting surface 33 . as can be appreciated , as thicker tissue is encountered and clamped between the anvil 20 and cartridge 32 , the clamped tissue applies an inward force toward the cartridge 32 ( or downward as viewed in the orientation of fig5 , 10 and 13 ) on the t surface 34 b , 35 b of cam adjusting members 34 , 35 . such downward force causes pivot arms 42 , 41 and 48 , 40 to pivot to change the pusher contact position of the cam elements 39 a , 39 b as described in detail below . as can be appreciated , the terms upward and downward refer to the orientation of the stapler / components shown in the figures , it being understood that if the orientation of the stapler / components changes , the upward and downward references would likewise change . with reference to fig3 , 4 and 5 , pivot arm 42 has an outer region 42 a which is in contact with a lower surface of tab 34 a of camming element 34 . in the normal position , the cam adjustment element 34 is in its upward position with surface 34 furthest from the tissue contacting surface 33 of cartridge 32 due to the biasing force of springs 36 a , 36 b . first pivot arm 42 engages second pivot arm 41 which is attached to , or alternatively in abutment with , the sled 38 at inner region 41 b . when surface 42 a of tab 34 forces inner region 42 a of pivot arm 42 downwardly , pivot arm 42 pivots about pin 42 c ( counterclockwise as viewed in fig5 ). such pivotal movement causes inner region 42 d to engage outer region 41 d of second pivot arm 41 , causing arm 41 to pivot about pin 41 c ( clockwise as viewed in fig5 ) so that inner region 41 b is forced in a direction toward the sled 38 ( downwardly as viewed in the orientation of fig5 ). such movement of inner region 41 b forces sled 38 in a direction away from the tissue contacting surface 33 ( downwardly as viewed in fig4 and 5 ). this changes the plane in which the sled 38 travels to contact the staple pushers 36 . ribs 56 a , 56 b of sled 48 are forced out of the upper retaining or locking recesses 49 a , 49 b formed in the inner wall of cartridge 32 and are moved to engage different ( lower ) retaining recesses at a different “ level ” of the sled 38 . similarly , with reference to fig3 and 5 , first pivot arm 48 has an outer region 48 a which is in contact with a surface of tab 35 a of cam adjustment member 35 . in the normal position , cam adjustment member 35 is in its upward position with tissue engagement surface 35 b furthest from tissue contacting surface 33 of cartridge 32 due to the biasing force of springs 37 a , 37 b . first pivot arm 48 engages second pivot arm 40 which is attached to , or alternatively in abutment with , the sled 38 at inner region 40 b . when outer region 48 a is forced downwardly by tab 34 a , first pivot arm 48 is pivoted about pin 48 c ( clockwise as viewed in fig5 ) such that inner region 48 c engages outer region 40 d of second pivot arm 40 . this forces arm 40 to pivot about pin 40 c ( counterclockwise as viewed in fig5 ), causing inner region 40 b to apply a downward force to sled 38 , thereby forcing sled 38 in a direction away from the tissue contacting surface 33 ( downwardly as viewed in fig5 ). this , in conjunction with pivot arms 41 , 42 changes the plane in which the sled 38 travels to contact the staple pushers 36 . ribs 56 a , 56 b are forced out of the retaining or locking recesses 46 a , 46 b and 49 a , 49 b formed in the inner wall of cartridge 32 and moved to engage different ( lower ) locking recesses e . g . recesses 46 c , 46 d and 49 c , 49 d . this different position is shown in fig1 . in fig1 , the first pivot arms 48 , 41 have pivoted even further , due to the force of the thicker tissue on cam adjusting members 34 , 35 , causing respective second pivot arms 41 , 40 to pivot further , applying an additional force on the sled 38 , thereby forcing it further from tissue contacting surface 33 than in fig1 , with the ribs 56 a , 56 b engaging lower recesses 46 e , 46 f and 49 e , 49 f of the cartridge 32 . as can be appreciated , when the sled 38 is closer to the tissue contacting surface 33 , ( for thinner tissue ) the camming elements 39 a , 39 b are closer to the staple pushers 36 so that their advancement will force the staples further out from the respective slots 52 into engagement with the anvil . this is shown in fig6 , 8 and 9 where the staple 60 forms a smaller tissue enclosure area , e . g . a tighter b shape . when the sled 38 is further from the staple pushers 36 due to thicker tissue , the camming elements 39 a , 39 b are further from the staple pushers 36 , due to the changed position ( level ) of the sled 38 , and thus the angled camming surfaces contact the pushers 36 at a different ( lower ) region . thus , the staples 60 will form with a larger tissue enclosure space as shown in fig1 and 12 . when even thicker tissue is encountered , the camming elements 39 a , 39 b will be located even a further distance from staple pushers 36 , contacting the pushers at a still lower region , so that the staples 60 will form an even larger tissue enclosure area to accommodate the thicker tissue . this is illustrated in fig1 and 15 . stated another way , the angled camming surfaces 55 a , 55 b of the camming elements 39 a , 39 b will contact a different curved contacting region of the staple pushers 36 , depending on the position ( level ) of sled 38 with respect to the pushers 36 of cartridge 32 . fig1 - 18 illustrate an alternate embodiment of the present disclosure for adjusting the plane of the sled and camming elements . in this embodiment , a linkage mechanism is provided to adjust the “ level ” of the sled in response to tissue thickness . more specifically , a sled 138 has a pair of outer camming elements 139 a and a pair of inner camming elements 139 b , having respective angled camming surfaces 155 a , 155 b , configured for engagement with staple pushers to advance staples out of the cartridge in the same manner as described above with the embodiment of fig1 - 15 . the linkage mechanism includes a rocker arm 162 , a pivot arm 160 with an arcuate region 161 and a connector 165 . rocker 162 has a transverse aperture 162 a to receive locking pin 164 which also extends through opening 165 a in connector 165 . the curved outer surface 165 b of connector 165 is seated within arcuate region 161 of pivot arm 160 . curved end 162 b of rocker 162 is received within opening 134 c of tab 134 a of cam adjusting element 134 . similarly , pivot arm 170 has an arcuate region 171 . rocker 172 has a transverse aperture 172 a to receive locking pin 174 which also extends through opening 175 a in connector 175 . the curved outer surface 175 b of connector 175 is seated within arcuate region 171 of pivot arm 170 . curved end 172 b of rocker 172 is received within an opening of a tab of a second cam adjusting member ( not shown ) identical to cam adjusting member 134 . sled 138 has ribs or teeth 156 a , 156 b on opposing sides which are identical in structure and function to the ribs 56 a , 56 b of sled 38 of fig2 and engages locking recesses in the cartridge to retain the sled in its radial position in the same manner as described above with sled 38 . in use , sled 138 is automatically adjustable based on the tissue thickness . this occurs as the cam adjusting members are forced away from the tissue contacting surface of the cartridge when encountering thicker tissue ( in the same manner as described above for cam adjusting members 34 , 35 ). when forced away from the tissue contacting surface of the cartridge , they apply an inward force ( downwardly in the orientation of fig1 - 18 ) on rockers 162 ( and rocker 172 ), causing it to pivot as seen in fig1 . note fig1 and 18 show movement of one of the linkage mechanisms ( rocker 162 , pivot arm 160 , etc . ), it being understood that rocker 172 , pivot arm 170 and connector 175 of the other linkage mechanism operates in a similar manner . this pivoting of the rocker 162 forces connector 165 upwardly , forcing the end 167 of pivot arm 160 upwardly so that it rotates clockwise about the support pin 174 so the inner end 169 ( attached to or abutting sled 138 ) applies a downward force on the sled 138 . for brevity , only the two extreme positions of the sled 138 are shown , with fig1 showing the sled 138 in its uppermost position , closest to the tissue contacting surface of the cartridge for thinner tissue , and fig1 showing the sled 138 in its lowermost position , furthest from the tissue contacting surface of the cartridge to adjust for thicker tissue . note spring 170 , connector 175 , and rocker 172 act in a similar manner to adjust the position of the sled 18 , applying a force on a second region of the sled by end 179 ( fig1 ) of pivot arm 170 which is attached to or in abutment with sled 138 . as can be appreciated with reference to the figures , the difference in location or “ level ” of the sled 38 , 138 , i . e . position on different planes , enables the instrument to automatically adjust to tissue of different thickness . that is , the tissue thickness itself dictates the position of the cam adjustment members which in turn controls the position of the sled 38 , 138 . the position of the sled 38 , 138 in turn affects the extent of deployment of the staples 60 due to the varied position of the angled camming surfaces of the camming members 39 a , 39 b , 139 a , 139 b which contact the staple pushers . accordingly , the extent of staple deployment is automatically determined by the tissue thickness . it should be appreciated that although three discrete positions of the sled are illustrated , a different number of positions are contemplated , including an infinite number of variations of the planes of the sled . it should be appreciated that the adjustable planes for the camming elements of the present disclosure can also be used with other staplers , including , but not limited to other linear staples and endoscopic linear staplers . this cam arrangement can be used for example with the endoscopic surgical stapler 200 of fig1 , which has an elongated tubular portion 212 , an anvil assembly 214 pivotally mounted at a distal end portion of the elongated tubular portion 212 and a cartridge assembly 220 . the anvil and cartridge assemblies 214 , 220 are moved into approximation to clamp tissue therebetween . a handle 230 is squeezed to clamp the anvil and fire the staples in the manner disclosed in u . s . pat . nos . 5 , 762 , 256 and 5 , 865 , 361 , the entire contents of which are incorporated by reference . although described for fastener applying apparatus for firing staples formed by an anvil , the camming elements of this disclosure could also be used in fastener applying apparatus for firing two part fasteners . while the above description contains many specifics , these specifics should not be construed as limitations on the scope of the present disclosure , but merely as illustrations of various embodiments thereof . therefore , the above description should not be construed as limiting , but merely as exemplifications of various embodiments . those skilled in the art will envision other modifications within the scope and spirit of the disclosure .
a surgical fastener applying apparatus comprising a cartridge section having a cartridge containing a plurality of fasteners and an anvil section having an anvil for receiving the fasteners when advanced from the cartridge . the cartridge and anvil sections clamp tissue therebetween . a cam member is slidable within the cartridge section to fire the fasteners , and is movable from a first position defining a first distance from the anvil to a second position defining a second different distance from the anvil . a cam adjusting member is operably associated with the cam member and moves the cam member from the first position to the second position in response to a thickness of tissue clamped between the anvil and cartridge sections .