Patent GB-1495211-A (GB)
Title: Three-stage surgical instrument
IPC: A61B17/068
Filed: 1975-10-14
Abstract: 1495211 Surgical staplers UNITED STATES SURGICAL CORP 14 Oct 1975 [18 Oct 1974] 42054/75 Heading A5R A hand-held, three-stage surgical instrument 10 is arranged to operate a staple-carrying cartridge (34), Fig. 1 (not shown) mounted on the nose 26 of the body 12, for, in successive stages, clamping, ligating and dividing organic tubular structures. The cartridge includes anvils (5) and a movable wrap (9) between which the structure is clamped, the wrap in this clamping position being controlled by a saddle 24, the cartridge also including pusher elements for urging two staples towards the anvils and crimping them, which elements are controlled by a saddle 22, and a structure-dividing knife which is controlled by a saddle 20, all saddles extending from the nose 26. Saddles 20, 22, 24 are integral with a knife rod 28, a pusher sleeve 30 and a wrap sleeve 32 respectively. A trigger 16 is pivotally mounted to the body 12 by a pin 42 and has at one end a bell crank 44 with a pin 46 supporting rollers 48 in a recess 50 of a pivotally mounted rear link 52. Clockwise rotation of link 52, effected by actuation of the trigger, is limited by a set screw 102 on the link abutting a stop 106 and counter-clockwise rotation is limited by a similar set screw 100 abutting a stop 104. The rear link 52 is pivotally connected to a forward link 56 which is pivotally connected to a thrust block 60 by a pin 62. Actuation of the trigger causes the thrust block to move in the direction of arrow 140, against the bias of a return spring 76 which seats in the forward end of the block. The block is fixed relative to sleeve 30 by a retainer 64 so the sleeve also moves in this direction. Sleeve 30 is coupled to the wrap sleeve 32 by shifter dogs (124) Fig. 9 (not shown) on sleeve 32 mounted in windows (126) and movable radially relative to sleeve 32, extending into an annular channel (108), Fig. 9, on the outer face of sleeve 30. The dogs may subsequently extend into a complementary channel 116 in a wall of the body 12 @ couple sleeve 32 thereto. A nose 136 of a stop 132 in the nose 26 provides an abutment for saddle 24 to limit the forward motion of this saddle and wrap sleeve 32. During initial movement in the direction of arrow 140 sleeves 32 and 30 and knife rod 28, with their saddles, move together, saddle 20 being carried with the pusher sleeve 30. From the position in Fig. 2 to just before that of Fig. 6 (not shown) dogs (124) project into channel (108) but as saddle 24 abuts the nose 136 they project into channel 116 so the pusher sleeve and knife rod continue motion with the thrust block, Fig. 6. A knife actuating lever 80 is pivotally mounted to the trigger by a pin 82 and is biased, by a spring 84, to the Fig. 2 position. Lever 80 has a contact pad 86 and a cam follower 88 guided by the camming surface 53 of link 52, thus the lever 80 moves counter-clockwise. A follower 92 threaded onto the rear of the knife rod moves with the thrust block faster than the lever 80 moves, until pin 58 reaches the position 58' in Fig. 7. The end 96 of pusher sleeve 30 serves as a retainer for a knife return spring 98 which urges saddles 20 and 22 towards each other. Subsequently the saddle 20 is driven away from saddle 22 to divide the structure, Fig. 7. Fig. 5 (not shown) illustrates a clutch mechanism (150) including a cam block (152) cooperating with thrust block 60, having an inclined surface (156) facing a thrust bar (158) with a spacing (160) and a cam roller (162) therebetween, the movement of the roller being confined by a notch (172) in the thrust bar, the roller preventing the thrust bar from returning to its relaxed position, Fig. 5, until completion of a thrust stroke. When cartridge 34 is associated with the instrument 10 the stroke of saddle 22 is less than that shown in Fig. 7 and the stroke limitation is absorbed by the collapse of a set of Belleville washers 68, located in the thrust block 60, as a retainer 64 is moved toward the rear of the instrument by pusher sleeve 32. The clutch mechanism ensures completion of the operation once the first stage is commenced.