Electrosurgical device

Abstract

Embodiments of the present invention provide an improved surgical instrument (1) with several improvements and advantages over the prior art. The surgical instrument (1) includes an end effector (14) capable of performing various operations, including grasping, cutting, sealing, and / or coagulating tissue, one of the operations being controlled by a handle (10) that is movable relative to the instrument (1) to move the end effector (14) between two states. The present invention provides a simplified locking mechanism for this movable handle (10). Specifically, the locking mechanism consists of a single, integrally formed component arranged to engage the handle (10) so that the end effector (14) is held in one state, leaving the user with one hand free to perform other functions of the instrument (1).Thus, in use, a user can use the surgical instrument (1) to grasp tissue between the end effector (14) by activating the end effector (14) using the handle (10), and then use the locking mechanism to lock the handle (10) in the end effector activation position so that the surgeon can remove his hand from the handle (10) and perform another task.

Description

Field of the invention

[0001] Embodiments of the present invention described herein relate to an electrosurgical device, and more particularly to electrosurgical forceps wherein a mechanical blade provides a tissue cutting function in combination with electrosurgical electrodes that provide a tissue coagulating or sealing action. Background of the invention and prior art

[0002] Electrosurgical instruments provide advantages over conventional surgical instruments because they can be used for the purpose of coagulating and sealing tissue. One such prior art arrangement is known from US 2015 / 223 870 A1, which describes an endoscopic bipolar forceps comprising a housing and a shaft, the shaft having an electrosurgical end effector assembly at its distal end, which includes two jaws for grasping tissue between them. Each jaw member is adapted to be connected to an electrosurgical energy source, thereby enabling the sealing of tissue held between the jaws. A drive assembly is housed in the housing to move the jaw members.A movable handle is also provided, so that movement of the handle actuates the control assembly to move the jaw members relative to each other. A knife channel is part of the end effector to allow forward and backward movement of a blade within the knife channel, in turn enabling tissue cutting.

[0003] Further prior art arrangements include the following: US 5 730 740 A, US 5 104 397 A, US 4 800 880 A, WO 98 / 14 124 A1, US 2012 / 0 109 186 A1, US 5 352 235 A, WO 2014 / 074 807 A1, US 7 846 161 B2, WO 2008 / 024 911 A2, US 5 776 130 A, US 6 039 733 A, US 6 179 834 B1, US 7 131 971 B2, US 7 766 910 B2, EP 2 628 459 A2, US 2014 / 0 221 999 A1, US 7 083 618 B2, US 2009 / 0 248 020 A1, US 2015 / 0 209 103 A1, US 5 797 938 A, US 7 101 373 B2, US 2015 / 0 331 443 A1 and US 2012 / 0 184 989 A1. Brief description of the invention

[0004] Embodiments of the present invention provide an improved surgical instrument with several improvements and advantages over the prior art. The surgical instrument includes an end effector capable of performing various operations, including grasping, cutting, sealing, and / or coagulating tissue, one of the operations being controlled by a handle that is movable relative to the instrument to move the end effector between two states. Embodiments of the present invention provide a simplified locking mechanism for this movable handle. Specifically, the locking mechanism consists of a single, integrally formed component arranged to engage the handle so that the end effector is held in one state, e.g.in a closed position, leaving the user with one hand free to perform other functions of the instrument. Thus, in use, a user can use the surgical instrument to grasp tissue between the end effector, activate the end effector using the handle, and then use the locking mechanism to lock the handle in the end effector activation position, allowing the surgeon to remove their hand from the handle and perform another task.

[0005] In view of the above, one aspect provides a surgical instrument comprising a handpiece, the handpiece comprising first and second handles, at least one of the handles being movable relative to the other between an open position in which the handles are spaced apart from each other and a closed position in which the handles are brought closer together, and an end effector movable between a first and a second state in response to relative movement of the at least one handle, the first handle comprising a snap-in fitting comprising: i) a body portion slidably disposed in a channel in the first handle, ii) a spring element formed integrally with the body portion for biasing the body portion in a direction within the channel, iii) a cam member present on the body portion, the cam member comprising first and second cam surfaces and a groove therebetween, iv) a locking bar extending from the body portion and movable by a user of the instrument between a first and a second position to manually slide the body portion within the channel of the first handle, wherein the second handle includes a cam follower engageable with the latching molding when the first and second handles are moved to their closed position, the cam follower engaging the first cam surface when the first and second handles are moved to their closed position, the cam follower being received in the groove when the first and second handles are in their closed position, the cam follower engaging the second cam surface when the first and second handles are moved to their open position, characterized in that the latching molding comprising the body portion, the spring element,the cam element and the locking rod, is formed as a single, one-piece molded component.

[0006] To operate the locking mechanism, the user simply moves the first and second handles to their closed position so that the cam follower passes through the first cam surface, and the body portion is pulled against the force of the spring element to hold the cam follower in the groove. The user is thus able to leave the end effector in the second state, freeing one hand to perform other functions. To release the locking mechanism, the user moves the first and second handles to the closed position, and the spring element slides the body portion up the channel to allow the cam element to engage the second cam surface. Thus, the single, integrally molded component and cam follower provide a simplified locking mechanism that is easy to assemble and operate in the instrument handpiece.

[0007] The latching molding may further include an override button, wherein the override button is integrally formed at a position on the body portion and is movable to change the position of the cam member to allow the cam follower to exit the groove and subsequently allow the first and second handles to return to their open positions. Thus, if the latching mechanism fails for any reason, the user would be able to release the first and second handles from the closed position.

[0008] Optionally, the cam element comprises a V-shaped molded protrusion, wherein the first and second cam surfaces are formed by opposite sides of the protrusion, and the groove is formed in the top surface of the V-shaped protrusion. Such a V-shape can be easily molded with the rest of the molded component.

[0009] The cam follower may comprise a pin, the pin being mounted on a cantilever extending from the second handle. As such, this pin may easily and smoothly traverse the first and second cam surfaces. The spring may comprise a curved member disposed at one end of the body portion. Such an arrangement may be easily formed integrally with the remainder of the body portion in a molding process. In some arrangements, the end effector comprises first and second jaws, wherein the first and second states of the end effector include open and closed positions of the jaws. For example, the end effector may be caused to move from an open to a closed position for grasping tissue.

[0010] The handpiece may further include a trigger operable to perform an action in addition to moving the end effector between its first and second states. In some embodiments, the trigger-operable action comprises longitudinal displacement of a mechanical cutting blade. For example, if the end effector is a pair of opposing jaws in a tissue-engaging position, a cutting blade may be actuated between the jaws to cut the tissue clamped therebetween.

[0011] As noted, the latching molding further comprises a locking bar, the locking bar extending from the housing and being movable by a user of the instrument between first and second positions to manually translate the body portion within the channel and thereby affect the actuation of the latching member. For example, the latching molding may be configured such that upon movement of the locking bar to its second position, the cam follower engages the second cam surface instead of the first cam surface when the first and second handles are moved to their closed positions. Additionally or alternatively, the latching molding may be configured such that the cam follower is never received in the groove when the locking bar is in its second position. In either case, the user may thus use the locking bar to manually override the latching mechanism.

[0012] As noted above, the locking bar is integrally formed on the body portion, thereby reducing the number of components that must be assembled into the handpiece of the instrument.

[0013] In a second aspect, a latching mechanism is provided for the handle of a surgical instrument such as one described herein, the handle having a housing and an actuating member movable relative to the housing between a first position and a second position for actuating an end effector, the latching mechanism comprising: a protruding member disposed on the actuating member; and a single, integrally formed latching molding received in the housing, the latching molding comprising: (i) a body portion slidably disposed in a channel in the housing, the body portion including guide means defining first and second paths and a groove therebetween, the projecting member being arranged, in use, to traverse the first path as the actuating member is moved from the first position to the second position and to traverse the second path as the actuating member is moved from the second position to the first position; (ii) a locking bar extending from the body portion and movable between a first and a second position by a user of the instrument to manually slide the body portion within the channel in the first handle; and (iii) a spring member for biasing the body portion in a direction in the channel such that the projecting member is received in the groove when the actuating member is in the second position.

[0014] Such an arrangement, as explained above, provides ease of use by the user as well as a simplified arrangement which is easy to assemble.

[0015] In a further aspect, an embodiment of the invention provides a surgical instrument comprising a handpiece comprising a first and a second handle, at least one of the handles being movable relative to the other between an open position in which the handles are spaced apart from each other and a closed position in which the handles are brought closer together, and an end effector movable between a first and a second state in response to the relative movement of the at least one handle, the first handle comprising a snap-in molding, which in turn comprises: i) a body portion slidably disposed in a channel in the first handle; ii) a spring element integrally formed with the body portion for biasing the body portion in a direction within the channel; iii) a cam member present on the body portion and comprising first and second cam surfaces and a groove therebetween; iv) a locking rod extending from the body portion and movable by a user of the instrument between a first and a second position to manually slide the body portion within the channel of the first handle; wherein the second handle includes a cam follower engageable with the latching molding when the first and second handles are moved to their closed positions, the cam follower engaging the first cam surface when the first and second handles are moved to their closed positions, the cam follower being received in the groove when the first and second handles are in their closed positions, the cam follower engaging the second cam surface when the first and second handles are moved to their open positions, the spring member and the locking rod extending in the same plane from the body portion.

[0016] Further aspects, features and advantages of embodiments of the invention will become apparent from the appended claims. Brief description of the drawings

[0017] Embodiments of the invention will now be further described by way of example only and with reference to the accompanying drawings, in which like reference numerals refer to like parts and in which: Fig. 1 is a side view of an electrosurgical instrument according to an embodiment of the present invention; Fig. 2 is a side view of a handle of the electrosurgical instrument according to the embodiment of the present invention; Fig. 3 is an exploded view of an electrosurgical instrument according to the embodiment of the present invention; Fig. 4 a cross-sectional view of the clamping mechanism of the electrosurgical instrument from Fig. 3 in open arrangement; Fig. 5a a cross-sectional view of the clamping mechanism of the electrosurgical instrument of Fig. 3 in closed arrangement; Fig. 5b a cross-sectional view of the clamping mechanism of the electrosurgical instrument of Fig. 3 in a closed arrangement with tissue clamped therein; Fig. 6 a cross-sectional view of a part of the clamping mechanism of the electrosurgical instrument of Fig. 3 shows; Fig. 7 a perspective view of the clamping mechanism of the electrosurgical instrument of Fig. 3 shows; Fig. 8a-f the assembly of a part of the electrosurgical instrument from Fig. 3 show; Fig. 9a-b Cross-sectional views of a part of the electrosurgical instrument from Fig. 3 are; Fig. 10a-c a blade guide part of the electrosurgical instrument made of Fig. 3 show; Fig. 11 a locking part of the electrosurgical instrument made of Fig. 3 shows; Fig. 12 a blade angle alignment part of the electrosurgical instrument from Fig. 3 shows; Fig. 13a-b Cross-sectional views of the blade angle alignment part of the electrosurgical instrument from Fig. 3 show; Fig. 14a-b a blade angle control wheel part of the electrosurgical instrument from Fig. 3 show; Fig. 15a-b the rotational movement of the blade angle control wheel of the electrosurgical instrument Fig. 3 show; Fig. 16a-d the rotational movement of the end effector of the electrosurgical instrument Fig. 3 show; Fig. 17 a cross-sectional view of the electrosurgical instrument from Fig. 3 and illustrates a wiring path; Fig. 18a-b show details of an electrical wiring path used in the electrosurgical instrument of Fig. 3 is used; Fig. 19 shows further details of an electrical wiring path used in the electrosurgical instrument of Fig. 3 is used; Fig. 20a-b Side views of part of the cutting mechanism of the electrosurgical instrument from Fig. 3 are; Fig. 21 is a cross-sectional view of a portion of the cutting mechanism of the electrosurgical instrument of Fig. 3 is; Fig. 22 is a cross-sectional view of another part of the cutting mechanism of the electrosurgical instrument of Fig. 3 shows; Fig. 23 a partially transparent perspective view of the cutting mechanism of the electrosurgical instrument of Fig. 3 is; Fig. 24a-c the assembly of a part of the cutting mechanism of the electrosurgical instrument from Fig. 3 show; Fig. 25a-c Cross-sectional views of the cutting mechanism and the clamping mechanism of the electrosurgical instrument from Fig. 3 show; Fig. 26a-f are cross-sectional views illustrating the operation of the locking mechanism of the electrosurgical instrument of Fig. 3 illustrate; Fig. 27 is a diagram showing the cutting mechanism of the electrosurgical instrument Fig. 3 illustrates; Fig. 28a-b are line drawings showing the cutting mechanism of the electrosurgical instrument from Fig. 3 illustrate; Fig. 29a-b a blade angle alignment part of the electrosurgical instrument from Fig. 3 show; Fig. 30 is a perspective view of a portion of the clamping mechanism of the electrosurgical instrument of Fig. 3 is; Fig. 31 a partial cross-sectional view of the cutting mechanism and the clamping mechanism of the electrosurgical instrument of Fig. 3 is; Fig. 32 a partial cross-sectional view of the cutting mechanism and the clamping mechanism of the electrosurgical instrument of Fig. 3 is; Fig. 33 the blade angle control wheel part and the electrode control switch of the electrosurgical instrument Fig. 3 shows; Fig. 34 the blade angle control wheel part of the electrosurgical instrument Fig. 3 shows; Fig. 35a-b show the handle of the electrosurgical instrument of Fig. held by users with different sized hands; Fig. 36a-c the rotational movement of the end effector of the electrosurgical instrument Fig. 3 show; Fig. 37 the rotational movement of the blade angle control wheel of the electrosurgical instrument Fig. 3 shows; Fig. 38 is a schematic perspective view of an example of an end effector; Fig. 39 is an enlarged perspective view of a portion of the end effector of Fig. 38 is; Fig. 40 is a schematic cross-sectional view of a part of the end effector of Fig. 38 is; Fig. Figure 41 is a schematic perspective view of an alternative end effector; Fig. 42 is an enlarged perspective view of a portion of the end effector of Fig. 41 is, Fig. 43 a schematic cross-sectional view of a part of the end effector of Fig. 41 is, Fig. 44 is a schematic cross-sectional view of part of another alternative end effector; Fig. 45 is an illustration of an electrosurgical system including a generator and an instrument according to embodiments of the invention; Fig. 46 furthermore a locking part of the electrosurgical instrument from Fig. 3 shows and Fig. 47a-e the distal end of the in the electrosurgical instrument from Fig. 3 used cutting blade. Description of the embodiments

[0018] An embodiment of the invention will now be described. First, a brief overview of the overall embodiment will be given, followed by detailed descriptions of specific aspects thereof. 1. Overview of the structure of the instrument

[0019] Fig. Figure 1 shows an electrosurgical instrument 1 according to an example of the present invention. The instrument 1 includes a proximal handle portion 10, an outer shaft 12 extending in a distal direction from the proximal handle portion, and a distal end effector assembly 14 attached to a distal end of the outer shaft. The end effector assembly 14 may, for example, be a set of opposing jaws arranged to open and close and include one or more electrodes disposed on or as their opposing inner surfaces, which, in use, have terminals for receiving a radio frequency (RF) electrosurgical signal for sealing or coagulating tissue.The jaws are further provided with a slot or other opening in the opposing inner surfaces through which a mechanical cutting blade or the like can protrude upon activation by the user. In use, the handle 10 is activated by the user in a first manner to clamp tissue between the jaws 14 and in a second manner to supply RF current to the electrodes to coagulate the tissue. The jaws 14 may be curved so that the active elements of the instrument 1 are always visible. This is important in vessel sealing devices used to operate on body regions that make it difficult for the user to view the device during use. The handle 10 may be activated by the user in a third manner to cause the blade to protrude between the jaws 14, thereby cutting tissue clamped therebetween.After completing the required cutting and sealing, the user can release the tissue from the jaws 14.

[0020] The handle 10 comprises, as in Fig. 2, a housing 20 made of two shell moldings 300, 302, which accommodates all components required for the actuation and rotation of the clamping jaws 14, the coagulating and cutting of tissue. The shell moldings in the assembled device are ultrasonically welded after the internal components have been arranged inside them. The handle 10 comprises a clamping handle 22 for clamping tissue between the clamping jaws 14, a trigger 24 for cutting the tissue, a switch 26 for activating and deactivating the RF supply to the electrodes in the clamping jaws 14 for coagulating tissue, and a rotary wheel 28 for rotating the clamping jaws 14 to reach tissue at different angles. The handle 10 is constructed so that the instrument 1 and all its functions can be operated with just one hand, with all operating mechanisms being easily accessible.

[0021] Fig. Figure 3 shows all of the features of instrument 1 required to perform its functions, including those housed in the two shell moldings 300, 302 of the housing 20. To clamp tissue between the jaws 14, a clamping mechanism is actuated using the clamping handle 22. The clamping handle 22 further includes a collar ring 304, which includes a hinge 306 that acts as a pivot point about which the clamping handle 22 rotates. The hinge 306 may, for example, be two outwardly directed pins that engage corresponding moldings 308 formed integrally with the shell moldings 300, 302 to provide an anchor point about which the clamping handle 22 rotates. The clamping mechanism further includes a collar ring molding 310, a spring 312, and an inner molding 314, as shown in Fig. 4 to 7, all of which are arranged along a drive shaft 316.

[0022] The collar ring 304 includes a keyhole opening 318 in which the collar ring molding 310 is received. The opening 318 has a larger diameter at the top than at the bottom, with the collar ring molding 310 being arranged to be received in the lower part of the opening 318, as Fig. 8a. When assembled, the collar ring molding 310 fits easily through the larger part of the opening 318 so that the collar ring 304 is received between two flanges 800, 802, as Fig. 8b-c show. As Fig. As shown in Figure 8d, the collar ring 304 is then pushed upward to engage the smaller portion of the keyhole opening 318 with the collar ring molding 310. Once the hinge 306 is connected to the hinge moldings 308 within the housing 20, the collar ring molding 310 is retained in the lower portion of the opening 318, where it can rotate freely within the opening 318.

[0023] The collar ring molding 310, the spring 312 and the inner molding 314 are, as in Fig. 6, are held between protruding elements 600, 602 such that they cannot move axially beyond these protruding elements 600, 602. In this regard, the protruding elements 602 at the proximal end of the drive shaft 316 are compressible to allow the drive shaft 316 to pass through a channel 604 in the proximal end of the inner mold part 314. The drive shaft 316 is pushed through the channel 604 until it reaches an opening 606, at which point the protruding elements 602 are no longer compressed so that they lie flush against the walls of the drive shaft 316. Instead, the protruding elements 602 fan out and press against the walls of the opening 606 so that the width of the protruding elements 602 extends beyond the diameter of the channel 604. Consequently, the drive shaft 316 cannot be retracted through the channel 604 and is locked.

[0024] The spacing between the protruding elements 600, 602 is selected such that the spring 312 is at least partially compressed between the collar ring molding 310 and the inner molding 314. This pre-compression is essential to ensure that the correct clamping load is applied when the clamping mechanism is activated, as described in more detail below. Both the collar ring molding 310 and the inner molding 314 include cavities 608, 610 into which the spring 312 extends. In particular, a substantial portion of the length of the collar ring molding 310 accommodates the spring 312. This arrangement allows for a longer spring 312, which is important to ensure that the spring 312 never reaches its block length during use.

[0025] The main body of the drive shaft 316 lies within the outer shaft 12, with the distal end of the drive shaft 316 being connected to both the distal end of the outer shaft 12 and the clamping jaws 14. The drive shaft 316 moves axially within the outer shaft 12, and by this axial movement, the clamping jaws 14 are moved from an open to a closed position, as shown in Fig. 4 and Fig. 5a. The drive shaft 316 is coupled to the jaws 14, for example, by a drive pin 400 in a cam slot 402, with movement of the drive pin 400 in the cam slot 402 moving the jaws 14 between the open and closed positions. The connection between the drive shaft 316, the outer shaft 12, and the jaws 14 is such that rotational movement of the drive shaft 316 is transmitted to the outer shaft 12 and the jaws 14.

[0026] The outer shaft 12 and the drive shaft 316 are connected at a further point by a shaft member 320. The shaft member 320 is received in a socket 322 of the housing 20, thus connecting the outer shaft 12 to the housing 20. The outer shaft 12 is secured to the shaft member 320 by any suitable means, such as snap-in projections 900 that cooperate with corresponding grooves 902 in the shaft member 320, as shown in Fig. 9b. The drive shaft 316 is guided through an opening (not shown) adapted to the T-shaped cross section of the drive shaft 316 through the body portion of the waveform part 320, as shown by Fig. 10a. The shaft-shaped part 320 is arranged so that it can rotate freely in the socket 322. The shaft-shaped part 320 can, for example, comprise cylindrical flange elements 904, 906 that rotate in concentric mating surfaces 908, 910 provided in the shell-shaped parts 300, 302. Thus, the shaft-shaped part 320 rotates with the drive shaft 316, which in turn transmits this rotational movement to the outer shaft 12 and the clamping jaws 4. The shaft-shaped part 320 thus functions as a rotational guide and axial guide for the drive shaft 316.

[0027] The clamp handle 22 includes a latching element 324 arranged to cooperate with a latching molding 326 provided in the proximal end 328 of the housing 20. The latching molding 326 may be engaged by any suitable means, such as a molding pin 330 formed integrally with one of the shell moldings 300, 302, as shown in Fig. 3, or simply by the molding walls 1100, which are formed integrally with the shell molding 300, as in Fig. 11, are held in place. When the clamping handle 22 is directed toward the housing 20 to close the clamping jaws 14, the latching element 324 enters the housing 20 through an opening 1102 and engages the latching molding 326 to hold the clamping handle 22 in this position. As shown in Fig. 26a to 26f, the locking molding 326 includes a two-way spring 1104 and a cam path 1106 along which the locking element 324 moves. As shown in Fig. 46, the latching mechanism may also include an override component 4600 to allow the user to manually release the latching element 324 if it becomes stuck, as well as a locking component 4602 to disable the latching mechanism entirely. The override component 4600 and the locking component 4602 may be provided on the latching molding 326 or integrated into the interior of the housing 20.

[0028] As described above, the handle 10 further comprises a rotary wheel 28, wherein the rotary wheel 28 is arranged to enclose the inner mold part 314. For this purpose, the rotary wheel 28 and the inner mold part 314 have interlocking elements 1200, 1202, as shown in Fig. 12. These interlocking elements 1200, 1202 connect in such a way that the rotary wheel 28 and the inner mold part 314 rotate together, while still allowing axial movement of the inner mold part 314 within the rotary wheel 28, as shown in Fig. 13a-b. Thus, rotation of the rotary wheel 28 causes the inner mold part 314 to rotate, which consequently causes the drive shaft 316 and the collar ring mold part 310 to rotate. For stability reasons, the rotary wheel 28 includes cylindrical surfaces 1204 that slide in rotation on inner mating surfaces (not shown) formed integrally with the shell mold parts 300, 302.

[0029] To enable a user to rotate the jaws 14, the housing 20 has two openings 332, 334 through which notched portions 336 of the rotary wheel 28 protrude. The two openings 332, 334 are located opposite each other on either side of the handle and are trapezoidal in shape. In particular, the trapezoidal openings have parallel sides that are at right angles to the longitudinal axis of the handle, and one of the parallel sides may be longer than the other, with the longer side at the front end of the opening and the shorter side at the rear end of the opening. The notched portions 336 are chamfered in a suitable manner so that they fit the user's thumb or fingers. To this end, the notched portions 336 are cut at an angle to the plane of rotation, as shown in Fig. 14a-b. In particular, the angle of the beveled part of the notched sections should substantially correspond to the angle of the outer housing in the area of ​​the rotary wheel 28.

[0030] The rotary wheel 28 also comprises at least one stop element 1500 for limiting the degree of rotation, as in Fig. 5a-b. The stop element 1500 interacts with stop parts 1502, 1504, which are formed integrally with the housing 20. When the rotary wheel 28 is rotated, the stop element 1500 is blocked by the stop parts 1502, 1504, thereby preventing further rotation. The stop parts 1502, 1504 can, for example, limit the rotation of the rotary wheel to 270°. Similarly, the wave-shaped part 320 also includes a stop element 1600, which interacts with stop parts 1602, 1604, which are formed integrally with the housing 20, as shown in Fig. 16a-d. The stop element 1600 of the wave-forming part 320 and its corresponding stop part 1602, 1604 are aligned with respect to the stop element 1500 of the rotary wheel 28 and its corresponding stop parts 1502, 1504 such that rotation is restricted to the same extent. This means that when the rotary wheel 28 rotates, the radial point at which the stop element 1500 is blocked on the rotary wheel 28 coincides with the radial point at which the stop element 1600 is blocked on the wave-forming part 320. In Fig. 15b and Fig. 16a, the clamping jaws 14 were, for example, moved from a neutral orientation (which is Fig. 16b) is rotated 90° counterclockwise. This freedom of rotation means that the user can capture tissue from different angles without having to rotate the entire instrument 1.

[0031] As described above, the switch 26 is provided to activate or deactivate the RF signal 26 supplied to the electrodes in the jaws 14 via a suitable circuit, such as two ingress-protected switches on a small printed circuit board (PCB) 338. As Fig. As can be seen in Figure 17, the PCB 338 is connected to a connecting cable 1700 to receive the RF output from a generator (not shown) and to electrical leads 1702, 1704 to supply the RF current to the electrodes in the clamp jaws 14, such as a lead for the active electrode and a lead for the counter electrode. As shown in Fig. 17 and Fig. As shown in Figures 18a-b, the leads 1702, 1704 are wrapped beneath and around the shaft member 320 before entering a guide slot 1800 in the interior cavity 1802 of the shaft member 320 and extending down the outer shaft 12. Wrapping the leads 1702, 1704 around the shaft member 320 in this manner holds the leads 1702, 1704 in a compact arrangement to allow for easy assembly while allowing the drive shaft 316 to rotate. The leads 1702, 1704 are unwound and rewound with the rotation of the drive shaft 316. In addition, one of the shell moldings 300 also includes two molded compartments 1900, 1902 arranged in series to receive the line contacts 1904, 1906 that connect the active lines and return lines 1702, 1704 to the line 1908, 1910 of the intrusion-protected switches 338.The opposing shell molding 302 includes corresponding rib portions (not shown) to retain the contacts 1904, 1906 within the compartments 1900, 1902. Consequently, the two lead contacts 1904, 1906 are longitudinally separated such that only one contact can pass through each compartment 1900, 1902, thereby providing a physical barrier between each compartment 1904, 1906 and each lead. This prevents the risk of insulation damage to one of the leads caused by the contacts 1904, 1906 and, at the same time, protects the contacts 1904, 1906 themselves from fluids passing up the outer shaft 12 and into the housing 20.

[0032] With reference to the cutting mechanism, a blade 340 for cutting tissue clamped between the jaws 14 is provided in a central path 342 along the length of the drive shaft 316. The mechanism for actuating the blade 340 along the path 342 and between the jaws 14 is actuated via the trigger 24. The trigger 24 actuates a control assembly consisting of a trigger molding 344, a blade control molding 346, a blade collar ring molding 348, a tension spring 350, and a blade molding 352. The control assembly is arranged between the wave molding 320 and the handle collar ring 304 of the clamping mechanism. As shown in Fig. 20a-b, the drive assembly functions as an offset slider-crank mechanism by which the force exerted by the user on the trigger 24 is converted into axial movement of the blade molding 352 along the drive shaft 316, which in turn drives the fixed blade 340.

[0033] As from Fig. 21, Fig. 22 and Fig. 23, the blade molding 352 is arranged to be received in the blade collar ring molding 348. As Fig. 22, the blade collar ring molding 348 includes a lip edge 2200 that engages a recess 2202 extending around the periphery of the blade molding 352. As Fig. 23, the blade molding 352 has a T-shaped opening 2300 for receiving the drive shaft 316 and the blade 340. The blade molding 352 further includes an inner cutout 2100, as Fig. 21 shows, for the proximal end of the blade 340, wherein the end of the blade 2102 is shaped to fit the inner cutout 2100 of the blade molding 352 to allow easy assembly, as in Fig. 24a-c. The blade molding 352 is rotationally isolated from the blade collar ring molding 348, allowing the two moldings to rotate concentrically. Consequently, the blade molding 352 is capable of rotating with the drive shaft 316.

[0034] The clamping jaws 14 can be curved, as described above. To allow the blade 340 to be slid around the curve while retaining sufficient cutting ability, the frictional force of the cutting blade 340 in the curved path must be minimized. The frictional force is a product of the coefficient of friction of the blade 340 in the path 342 and the force exerted by the bending of the blade 340 on the walls of the path 342. This frictional force can be reduced, for example, by adding a low-friction coating to both sides of the blade and / or, preferably, weakening the blade 340 to grade the flexibility of the distal end of the blade so that it can bend along the path 342 while remaining rigid in the direction of the cutting force. The preferred weakening can be achieved, for example, by providing one or more openings 354 in the distal end, as shown in Fig. 3 and Fig. 47a-c, or by graduating the thickness of the blade 340, as in Fig. 47d. Alternatively, as shown in Fig. 47e, patterned laser cutouts 4712 or chemical etching may be applied in the distal end to control the bending stiffness along the blade length, wherein the spacing of such cutouts may be constant or may increase gradually from the distal to the proximal end.

[0035] During use, blood and tissue may accumulate in the distal end of the instrument 1. In particular, blood and tissue may cause the blade 340 to become lodged inside the drive shaft 316. Therefore, the distal end of the drive shaft 316 may include cut-out portions 1000, 1002 to reduce the surface of the drive shaft 316 to which blood and tissue may adhere, as shown in Fig. 10b-c. The cut-out sections may, for example, be such that the distal end comprises two side walls without a base or such that the distal end comprises a base with forked side walls. 2. Operating the instrument

[0036] After describing the overall design of the device, the overall operation of electrosurgical instrument 1 in use will now be explained. This is followed by a further detailed description of the design and operation of specific aspects of the device.

[0037] As explained above, the handle 10 of the electrosurgical instrument is arranged to i) clamp tissue between a set of jaws 14, ii) lock the jaws in place (if the user so desires), iii) deliver an RF signal to electrodes in the jaws 14 to coagulate the tissue clamped between them, and iv) move a blade 340 between the jaws 14 to cut the tissue clamped between them. The handle 10 can also rotate the jaws 14 to allow the user to clamp tissue at different angles without having to rotate the entire handle 10. Consequently, the tissue clamped between the jaws can be sealed using the same electrosurgical instrument before or during cutting. Furthermore, this effect can be achieved by the instrument with one-handed operation by the surgeon. 2.1 Clamping mechanism

[0038] To clamp tissue between the clamping jaws 14, the user pushes the clamping handle 22 toward the proximal end 328 of the housing 20 until the locking element 324 engages the locking molding 326 within the housing 20. This movement causes the control handle 22 to pivot about its joint 306, as shown in Fig. 8e-f, and pushes the edge of the collar ring 304 against the flange 800 to move the collar ring molding 310, the spring and the inner molding 314 along the drive shaft 316 in the proximal direction, as shown in Fig. 4 and Fig. 5a. As described above, the inner mold 314 is secured to the drive shaft 316 by means of protruding elements 602. Thus, when the inner mold 314 is axially retracted, the drive shaft 316 is also axially moved, causing the pin 400 to move into the cam slot 402 of the jaws 14, thereby closing the jaws 14. Thus, the load from the control handle 22 is transferred to the drive shaft 316 via the spring mechanism of the collar ring mold 310, spring 312, and the inner mold 314.

[0039] If tissue is clamped between the clamping jaws 14, as in Fig. As shown in Figure 5b, the spring 312 acts to limit the force acting on the tissue. Once the axial movement of the collar ring molding 310, spring 312, and inner molding 314 is complete and the collar ring 304 continues to press against the flange 800, the threshold compression force of the spring 312 is finally reached, so that the spring 312 begins to compress between the collar ring molding 310 and the inner molding 314. If the spring 312 compresses further, the control handle 22 can be moved to the locked position without exerting any further force on the clamped tissue. This means that the load of the control handle 22 is no longer transferred to the drive shaft 316, but is effectively absorbed by the spring 312. Thus, the spring 312 ensures that the correct amount of load is transferred to the clamping jaws 14.Without the spring 312, actuation of the trigger handle 22 results in a continued increase in the force transmitted to the drive shaft 316 and subsequently to the jaws 14 and the tissue. This could cause mechanical damage to the tissue if the user continues to press the trigger handle 22 to engage the latching element 324.

[0040] As explained above, the cavities 608, 610 in the collar ring molding 310 and the inner molding 314 cooperate to provide a larger spring 312. This allows for a greater spring stroke, so that the spring 312 is not compressed to its deflection length during use. Once the spring 312 reaches its deflection length, it would no longer absorb the force exerted by the control handle 22, and the force would be retransmitted to the clamping jaws 14. 2.2 Locking mechanism

[0041] If tissue is clamped between the clamping jaws 14, the clamping jaws 14 can be locked in a closed position by engaging the locking element 324 on the control handle with the locking molding 326 inside the housing 20, as shown in Fig. 26a-f. As the latching element 324 enters the housing 20 through the opening 1102, the latching element 324 engages the latching molded part 326, whereby the molded part 326 is pushed downward in the housing 20 and thereby extends the spring 1104. As shown in Fig. 26b-c, the latching element 324 moves upwardly along the side of the cam path 1106 until it reaches its maximum position. At this point, the control handle 22 can no longer be compressed, and the spring 1104 pulls the latching molding 326 inside the housing 20 upwardly again, so that the latching element 324 is inserted into the V-shaped compartment of the cam path 1106 to hold the control handle 22 in the compressed position and the clamping jaws 14 in the closed position, as shown in Fig. 26d.

[0042] In this locked position, the user's hand is free to operate the other functions of instrument 1, as explained below.

[0043] To release the latching element 324 from the housing 20 and to open the clamping jaws 14, the user must push the control handle 22 towards the housing 20 to release the latching element 324 from the compartment of the cam path 1106, as shown in Fig. 26e. The force of the spring 1104 pulls the latching molding 326 further up into the housing 20 so that the latching element 324 moves in the opposite direction down the side of the cam path 1106, as shown in Fig. 26e-f, and moved back out of the opening 1102. The locking molding 326 then returns to its original position inside the housing 20. 2.3 Cutting mechanism

[0044] When the clamping jaws 14 are in a closed position, the user may wish to cut the tissue clamped between them. To cut the tissue, a blade 340 is advanced between the clamping jaws 14 by actuating the control assembly.

[0045] The control assembly is a three-pivot arrangement that functions as a slider-crank mechanism. If the user pulls the trigger 24 back toward the housing 20, as shown in Fig. 25b-c, the trigger molding 344 is levered about a pivot point A which is anchored to the housing 20, such as in the form of outwardly directed pins 358 which engage with corresponding moldings 356 which are integral with the shell moldings 300, 302 of Fig. 3. This causes the pivot point B connecting the trigger molding 344 and the control molding 346 to be pushed past its central position, thereby translating the blade collar ring 348, the blade molding 352, and the blade 340 along the drive shaft 316 with a force sufficient to allow the blade 340 to cut the trapped tissue. In this regard, the load exerted on the trigger 24 is transmitted via the trigger molding 344 and the control molding 346 to the blade collar ring 348 and the blade molding 352. As the pivot point B moves past the center point to its extended position, the speed at which the blade collar ring 348 and the blade molding 352 are translated along the drive shaft 316 increases, thereby increasing the force acting on the blade 340.This increases the force with which the blade 340 cuts into the tissue without the user exerting additional force on the trigger 24.

[0046] The wave-shaped part 320 acts as a stop point for the blade collar ring 348 and the blade shaped part 352. Consequently, the pivot point B always remains above the other two pivot points A, C with respect to the drive shaft 316.

[0047] During actuation of the trigger 24, the force exerted on the trigger 24 is sufficient to overcome the compression force of the tension spring 350, so that the tension spring 350 extends along the same plane as the drive shaft 316 to allow axial movement of the blade collar ring 348 and the blade molding 352. Upon release of the trigger 24, the tension spring 350 is compressed again to retract the drive assembly to its original position. The tension of the tension spring 350 is sufficient to retract the blade 340 through thick tissue without user intervention. 2.4 Shaft rotation

[0048] During use, the user may need to access tissue from different angles without having to move the entire instrument 1. For this reason, the clamping jaws 14 are advantageously rotatable with respect to the handle 10 by means of the rotary wheel 28. This is particularly advantageous when the clamping jaws 14 are on a curved path, such as the one shown in Fig. 16a-d. As explained above, the rotary wheel 28 is connected to the inner mold part 314 via interlocking elements 1200, 1202, so that the inner mold part 314 rotates with the rotary wheel 28. Since the end of the drive shaft 316 is connected to the inner mold part 314, the drive shaft 316 also rotates, which in turn also rotates the clamping jaws 14 at their opposite end.

[0049] To enable this rotational movement without impairing the function of the clamping mechanism, the collar ring molding 310 is rotationally isolated in the handle collar ring 304 so that the collar ring molding 310 also rotates with the drive shaft 316. Similarly, the blade molding 352 is rotationally isolated in the blade collar ring 348 to enable rotation of the drive shaft 316 without impairing the function of the cutting mechanism.

[0050] To transmit the rotational movement to the outer shaft 12, the shaft member 320 is rotationally isolated in its socket 322. As described above, the shaft member 320 acts as a rotation guide to control the rotational movement relative to the shaft 316 along the entire length of the instrument 1. In addition, the active lines and return lines 1702, 1704 are arranged within the housing 20 to prevent damage to these lines 1702, 1704 by the rotating components. As described above, the lines 1702, 1704 are wound around the shaft member 320 to accommodate the extent of rotation of the drive shaft 316. Consequently, the lines 1702, 1704 are unwound and rewound around the shaft member 320 as it rotates. 2.5 Electrode activation

[0051] With the jaws 14 in a closed position, the user may wish to coagulate and seal the tissue clamped between them. To this end, the user initiates electrode activation using switch 26 on the housing 20, which is conveniently located for easy access by the user while operating the device with one hand. This delivers an RF signal to the electrodes in the jaws 14 to coagulate and seal the tissue. The RF signal may have a pure or mixed waveform, depending on the desired effect.

[0052] After an overview of the structure and operation of the entire device, further detailed descriptions of the structure and operation of certain aspects of it follow. 3. Structure and operation of the clamping mechanism

[0053] As described above, the proximal handle portion 10 of the electrosurgical instrument 1 includes a first mechanism for actuating an aspect of a distal end-effector assembly 14 such that the end-effector assembly 14 transitions between a first and a second state. The end-effector assembly 14 may, for example, be a set of opposing jaws 14 arranged to be opened and closed. The mechanism used to trigger the movement of these jaws 14 is the so-called clamping mechanism, which includes a control handle 22 and two barrel-shaped molded parts 310, 314 with a spring 312 compressed therebetween, all elements being arranged along an elongated rod 316 extending between the jaws 14 and the handle 10, as shown in Fig. 4 and Fig. 5a-b.

[0054] As from Fig. As can be seen in Figure 8a, the control handle 22 comprises a collar ring 304 in which the collar ring molding 310 is received. The collar ring 304 includes an opening 318 shaped like a keyhole or the number 8. The opening 318 consists of two adjacent openings 804, 806, with the upper opening 804 having a larger diameter than the lower opening 806.

[0055] The collar ring molding 310 is a cylindrical or barrel-shaped component with two flange portions 800, 802 spaced longitudinally apart. The diameter of the proximal flange 800 is larger than that of the upper and lower openings 804, 806. The diameter of the distal flange 802 is smaller than the upper opening 804 but larger than the lower opening 806.

[0056] During assembly, the collar ring molding 310 is first inserted through the upper opening 804, as shown in Fig. 8b-c. Since the distal flange 802 is smaller than the upper opening 804, it passes through it easily, while the proximal flange 800 is large enough to prevent the collar ring molding 310 from being fully advanced through the upper opening 804. As shown in Fig. 8d, the collar ring 304 is then pushed upward to engage the lower opening 806 with the collar ring molding 310.

[0057] After assembly, the collar ring molding 310 remains within the lower opening 806 of the collar ring 304 and is arranged so that its two flanges 800, 802 are present on both sides of the collar ring 304, as shown in Fig. 8e. Because the lower opening 806 has a smaller diameter than both flanges 800, 802, the collar ring molding 310 cannot be removed by simply pushing it through the lower opening 806. In contrast, the body portion of the collar ring molding 310 between the two flanges 800, 802 has a slightly smaller diameter than the lower opening 806. Thus, the collar ring molding 310 is sufficiently loosely received in the lower opening 808 to allow rotational movement.

[0058] As from Fig. As can be seen in Figure 8e, the longitudinal distance between the two flanges 800, 802 is only slightly larger than the thickness of the collar ring 304, so that the collar ring fits snugly between the flanges 800, 802. This ensures that the movement of the control handle 22 is transmitted directly to the collar ring molding 310 and subsequently to the other components of the clamping mechanism. This is particularly important to ensure that the clamping jaws 14 respond to the movement of the control handle 22 and that there is no delayed reaction between the actuation of the control handle 22 and the movement of the clamping jaws 14.

[0059] Once the collar ring molding 310 and the control handle 22 have been assembled, the remaining components can be assembled.

[0060] The drive shaft 316 is an elongated rod having one or more protruding elements 602 disposed at its proximal end, as shown in Fig. 6. The protruding elements 602 are flexible extensions that fan out from the surface of the drive shaft 316. This means that the protruding elements 602 are deformable so that they can be pressed flush against the surface of the drive shaft 316, but return to their original position upon release of any resistive force. This allows the drive shaft 316 to be easily pushed through all components of the clamping mechanism during assembly, as described below.

[0061] The collar ring molding 310 has an internal cavity divided into two parts. The first part is a narrow channel or slot 607 for receiving the drive shaft 316, with the distal end of the collar ring molding 310 including an opening 311, as shown in Fig. 3, which fits the T-shaped cross-section of the drive shaft 316. The diameter of the channel 607 is just slightly wider than the drive shaft 316 to provide a tight fit for better stability. Upon insertion of the drive shaft 316, the protruding elements 602 are pressed flat to allow the drive shaft to be pushed fully through.

[0062] The second portion is a chamber 608 sufficiently large to accommodate one end of the spring 312. The chamber 608 may extend over any suitable portion of the length of the collar ring molding 310. For example, the length of the chamber 608 may be approximately 25% of the length of the collar ring molding 310 up to 75% of the length of the collar ring molding 310.

[0063] The chamber 608 is substantially larger than the collar ring molding channel 607, so that when the drive shaft 316 is pushed through the collar ring molding 310, the protruding elements 602 extend outward again into their original structure when they reach the chamber 608.

[0064] The collar molding 310 and control handle 22 assembly is slid along the drive shaft 316 until the collar molding 310 reaches a second set of protruding elements 600. These protruding elements 600 have a greater width than the opening 311 on the collar molding 310 to provide a barrier that prevents the collar molding 310 from moving further along the drive shaft 316. To this end, the protruding elements 600 must be sufficiently rigid that the collar molding 310 cannot be pushed past them by applying force or pushing the protruding elements 600 inward.

[0065] The drive shaft 316 is then pushed through the center of the spring 312. The spring 312 preferably has a diameter only slightly larger than that of the drive shaft 312 to provide a closer fit between the spring 312 and the drive shaft 316. The spring 312 is then pushed along the drive shaft 316 until the end of the spring 312 fills the collar ring molding chamber 608.

[0066] The inner mold part 314 is a cylindrical or barrel-shaped component with an interior cavity divided into two sections. The first section is a chamber 610 in which one end of the spring 312 is received such that the spring 312 is partially enclosed by the collar ring mold part 310 and the inner mold part 314. The second section is a narrow channel or slot 603 for receiving the proximal end of the drive shaft 316. The channel 603 is divided into two parts 604, 606. The first part of the channel 604 is shaped to allow the drive shaft 316 to pass therethrough, flattening the flexible extensions 602 in the process. To this end, the diameter of the first channel part 604 is only slightly larger than that of the drive shaft 316 to provide a tight fit.The tight fit of the drive shaft 316 in both the collar ring molding channel 607 and the inner molding channel 603 means that the drive shaft 316 is held firmly in place. This increases the stability of the drive shaft 316 within the housing 20, which is particularly important for ensuring maximum control of the end effector 14.

[0067] The second portion of the channel 606 provides a shoulder 605 into which the protruding elements 602 can extend. Consequently, when the drive shaft 316 passes through the channel 604 and into the second channel portion 606, the flattened protruding elements 602 fan out back to their original uncompressed position. After the protruding elements 602 engage the shoulder 605 of the second channel portion 606, the drive shaft 316 cannot be retracted through the first channel portion 604 and is thus retained within the inner mold portion 314. To achieve this, the diameter of the second channel portion 606 must be sufficiently wide so that the protruding elements 602 extend beyond the diameter of the first channel portion 604. To achieve this snap-in connection, a protruding element 602 is only required on one side of the drive shaft 316.

[0068] This snap connection is configured such that any axial movement of the inner mold part 314 is transmitted to the drive shaft 316. Similarly, any rotational movement of the inner mold part 314, for example, by the rotary wheel 28 formed around the inner mold part 314, is also transmitted to the drive shaft 316.

[0069] To complete the assembly of the clamping mechanism, the drive shaft 316 is simply pushed through the collar ring molding 310, the spring 312 and finally the inner molding 314 until the protruding elements 602 snap into the second channel portion 606.

[0070] Once arranged along the drive shaft 316, the collar ring molding 310, the spring 312, and the inner molding 314 are arranged such that the spring 312 is partially enclosed by the collar ring molding 310 and the inner molding 314. By providing the collar ring molding chamber 608 and the inner molding chamber 610, wherein a substantial portion of the spring 312 can be received, a longer spring 312 can be used without requiring additional space within the handle 10. The larger the collar ring molding chamber 608 and the inner molding chamber 610, the longer the spring 312. In addition, the distance between the protruding elements 600, 602 means that the ends of the spring 312 are compressed by the end walls 612, 614 of the collar ring molding chamber 608 and the inner molding chamber 610, respectively, so that the spring 312 experiences an initial pre-compression during installation.This is important to ensure that the correct load is applied to the clamping jaws 14 when the handle 22 is operated to activate the clamping mechanism.

[0071] In addition, the inner mold part 314 may be received in another barrel-shaped mold part, such as the rotary wheel 28, as shown in Fig. 13a-b. Here, the inner mold part 314 rotates with the rotary wheel 28, but is free to move axially in the inner cavity 1300 of the rotary wheel 28 between a first position, as in Fig. 13a, and a second position as shown in Fig. 13b. Consequently, the rotation of the wheel 28 rotates the inner mold part 314, which in turn rotates the drive shaft 316 and the clamping jaws 14.

[0072] After all components have been assembled, the control handle 22 can be installed in the housing 20. For this purpose, the control handle 22 is connected to the housing at its hinge 306. The hinge 306 can, for example, be two outwardly extending pins that mate with corresponding hinge moldings 308 formed integrally with the shell moldings 300, 302. This provides an anchor point around which the control handle 22 can rotate.

[0073] Thus, the arrangement described above provides a mechanism for actuating the end effector assembly 14 that can be easily and safely assembled without any additional components.

[0074] In use, the user pushes the control handle 22 toward the proximal end 328 of the housing 20, thereby rotating the control handle 22 about its pivot 306. In doing so, the collar ring 304 presses against the proximal flange 800, thereby moving the collar ring molding 310 longitudinally. This longitudinal movement displaces the spring 312, the inner molding 314, and the drive shaft 316 back toward the proximal end of the handle portion 10, as shown in Fig. 5a. Since the drive shaft 316 is connected to the jaws 14, for example, by a pin 400 and cam slot 402 arrangement, the jaws 14 are moved from the open to the closed position. The load from the control handle 22 is transmitted to the drive shaft 316 via the spring mechanism of the collar ring molding 310, spring 312, and inner molding 314. This spring mechanism is particularly important because it limits the load acting on any tissue clamped between the jaws 14.

[0075] When the control handle 22 is pressed, the collar ring molding 310, the spring 312 and the inner molding 314 continue their axial movement until either the inner molding 314 reaches its most proximal position so that the clamping jaws 14 are completely closed, as shown in Fig. 5a, or the clamping jaws 14 cannot be closed further due to tissue 500 being clamped between them, as in Fig. 5b, in which case the control handle 22 is not fully actuated, so that it is held in place by the latching element 324. If the user continues to press the control handle 22 and the collar ring 304 continues to push against the flange 800, the threshold compression force of the spring 312 is finally reached, so that the spring 312 begins to be compressed between the collar ring molding part 310 and the inner molding part 314, as shown in Fig. 5b can be seen.

[0076] If the spring 312 is further compressed, the trigger handle 22 can be moved to the locked position without exerting any further force on the clamped tissue 500. This means that the load of the trigger handle 22 is no longer transferred to the drive shaft 316, but is effectively absorbed by the spring 312. Thus, the spring 312 ensures that the correct amount of load is transferred to the jaws 14. Without the spring 312, actuation of the trigger handle 22 continues to increase the load exerted on the drive shaft 316 and, consequently, on the jaws 14 and the tissue 500. This could result in mechanical damage to the tissue 500 when the user pushes the trigger handle 22 to engage the latching element 324.

[0077] For this reason, pre-compression of spring 312 is important to ensure that spring 312 takes over the load of handle 22 once inner molding 314 reaches its axial limit position. Similarly, a longer spring 312 allows for a greater spring stroke, so that spring 312 is not fully compressed to its block length during use. Once spring 312 reaches its block length, it would no longer absorb the force exerted by control handle 22, and the force would be retransmitted to jaws 14.

[0078] To hold the jaws 14 in their closed position, the locking element 324 on the control handle 22 must be engaged with the locking molding 326 inside the proximal end 328 of the housing 20, as shown in Fig. 26a-f.

[0079] Fig. 11 shows that the snap-in molding 326 is a single, integrally molded component including a body portion 1108, a spring member 1104, and a cam path 1106. The proximal end 328 of the housing 20 has parallel walls 1100 defining a channel 1110 in which the body portion 1108 is received. The width of the channel 1110 is selected such that the body portion 1108 is retained within the channel 1110, yet is still able to slide up and down within the channel 1110 during use, as described below. To this end, the snap-in molding 326 is preferably made of a low-friction material, such as polytetrafluoroethylene (PTFE), to allow the body portion 1108 to easily slide within the channel 1110 without sticking.For further stability in the channel 1112, a shaped pin 330 may be provided in the housing 20 which engages a cam slot 331 provided on the body portion 1108, as shown in FIG. Fig. 46 shown.

[0080] The spring 1104 is disposed at the end of the body portion 1108 and is arranged to bias the body portion 1108 upwardly within the channel 1110 toward the distal end of the housing 20. The spring 1104 may have any suitable construction; for example, the spring 1104 may have a curved shape or a loop shape, as shown in Fig. 11. The cam path 1106 is a protruding molded part formed on the body portion 1108. The cam path 1106 includes a first cam surface 1112, a groove 1114, and a second cam surface 1116 to form a V-shaped molded part.

[0081] The latching element 324 consists of an arm 1118 extending from the bottom of the control handle 22. The arm 1118 has a pin 1120 disposed at its end and adapted to travel along the cam path 1106.

[0082] In use, the latching element 324 is inserted into the housing 20 through an opening 1102. The pin 1120 engages the latching molding 326 so that the body portion 1108 is pulled downward in the channel 1110, thereby extending the spring 1104. As shown in Fig. 26b-c, the pin 1120 extends along the side of the first cam surface 1112 until it reaches the top of the "V." At this point, the control handle 22 can be depressed no further, and the spring 1104 pulls the body portion 1108 upward again within the channel 1110, causing the pin 1110 to enter the groove 1114, thereby holding the control handle 22 in the depressed position and the jaws 14 in the closed position, as shown in Fig. 26d shown.

[0083] To engage the control handle 22, the user simply needs to activate the control handle in the fully depressed position, wait until the pin 1110 engages the groove 1114, and then release the control handle 22. In this engaged position, the user's hand is free to perform other functions of the instrument 1, such as actuating the cutting mechanism using the trigger 24, rotating the clamping jaws 14 using the rotary wheel 28, or actuating the electrodes in the clamping jaws 14 using the switch 26.

[0084] To release the locking element 324 from the housing 20 and open the clamping jaws 14, the user must push the control handle 22 once more towards the housing 20. This releases the pin 1120 from the groove 1114, as shown in Fig. 26e. When the pin 1120 exits the groove 1114, the force of the preloaded spring 1104 pulls the body portion 1108 back up in the channel 1110 so that the pin runs along the side of the second cam surface 1116, as shown in Fig. 26e-f. When the pin 1120 reaches the bottom of the second cam surface 1116, it pushes the body portion 1108 further upward within the channel 1110, allowing the pin 1120 to exit the opening 1102. The body portion 1108 can then return to its original position within the channel 1110.

[0085] To release the control handle 22, the user simply needs to push the control handle 22 toward the proximal end of the housing 20 and then allow the control handle 22 to return to its original open position.

[0086] Furthermore, the latching molding 324 may include an override button 4600 integrally formed on the body portion 1108, as shown in Fig. 46, wherein the override button 4600 is engaged to change the position of the cam path 1106 such that the pin 1120 automatically exits the groove 1114 and releases the trigger handle 22. Thus, if the latching mechanism were to fail for any reason, the user would be able to release the trigger handle 22 to open the jaws 14.

[0087] The body portion 1108 may further be provided with an integrated locking bar 4602 to allow the user to release the entire locking mechanism, wherein the locking bar 4602 is movable between a first and a second position to manually slide the body portion 1108 within the channel 1110. When the locking bar 4602 is in the first position, the body portion 1108 is in its normal position, so the locking mechanism operates as above. The user can then move the locking bar 4602 to its second position, which moves the body portion 1108 upwardly within the channel 1110, allowing the pin 1120 to pass only through the second cam surface 1116, thereby preventing it from engaging the groove 1114.

[0088] Such a latching mechanism is also suitable for many end effector assemblies. For example, such a latching element can be provided on the trigger 24 for the cutting mechanism to hold the cutting blade 340 in the activated position.

[0089] Upon release of the locking element 324, the control handle 22 can be moved back to its original position. In doing so, the collar ring 304 releases the load exerted on the proximal flange 800 and pushes against the distal flange 802, thereby pulling the collar ring molding 310 back to its original axial position. Consequently, the spring 312, the inner molding 314, and the drive shaft 316 are also axially retracted, which in turn returns the jaws 14 to the open configuration. 4. Arrangement and operation of the cutting mechanism

[0090] Various features and aspects related to the structure and operation of the cutting mechanism will now be described. As described above, the proximal handle portion 10 of the electrosurgical instrument 1 includes a second mechanism for actuating another aspect of a distal end-effector assembly 14. For example, the end-effector assembly 14 may be a set of opposed jaws 14 and a blade 340, with the distal end of the blade 340 arranged to slide between the jaws 14 to cut tissue clamped between these jaws 14. The mechanism used to initiate movement of the blade 340, which is arranged in a central track 341 of the drive shaft 316, is called the cutting mechanism.The cutting mechanism includes a drive arm 2000, a blade drive molding 346, a blade collar ring molding 348, a blade molding 352, and a tension spring 350, all coupled together to form a 3-pivot point slider crank mechanism, as shown in FIG. Fig. 20a-b and Fig. 31 and Fig. 32 shown.

[0091] The drive arm 2000 is formed from a trigger 24 and the trigger molding 344, wherein the trigger 24 is a finger-gripping element for triggering the cutting mechanism and the trigger molding 344 is a collar ring with a C-shaped side profile and an opening 364 through which the drive shaft 316 is inserted. The point at which the trigger 24 and the trigger molding 344 meet provides a pivot point A about which the drive arm 2000 is rotated. This first pivot point A is anchored to the housing 20, for example, by means of outwardly facing pins 358 connected to corresponding moldings 356 formed integrally with the shell moldings 300, 302.

[0092] The distal end of the drive arm 2000, i.e., the end of the trigger molding 344, is pivotally connected to the blade drive molding 346 to form a second pivot point B. The blade drive molding 346 is an H-shaped frame with two parallel arms and a strut between them. Thus, the parallel arms of the blade drive molding 346 are pivotally connected to the trigger molding 344 at one end, for example, by means of outwardly facing pins 366 and mating connectors 368. At the opposite end, the parallel arms of the blade drive molding 346 are also pivotally connected to the blade collar ring molding 348 to form a third pivot point C, for example, by means of outwardly facing pins 372 and mating connectors 370.

[0093] As in Fig. As shown in Figures 21 to 23, the blade collar ring molding 348 is a cylindrical or barrel-shaped component having a chamber 2104 in which the blade molding 352 sits, the blade molding 352 being a cylindrical or barrel-shaped component having a body portion 362 that fits into the chamber 2104 of the blade collar ring molding 348. The blade molding 352 further includes a flange 360 ​​having a diameter that is larger than that of the chamber 2104 so that the flange 360 ​​abuts against the distal lip edge 2200 of the blade collar ring molding 348, as shown in Fig. 22. Consequently, the flange 360 ​​ensures that the correct end of the blade molding 352 is inserted into the blade collar ring molding.

[0094] The body portion 362 is provided with a small groove 2202 around its periphery to provide a shoulder that engages the distal nose 2200, so that the blade molding 352 and the blade collar ring molding 348 are connected to each other via a snap-fit ​​connection. The distal lip edge 2200 mates with the groove 2202 to retain the blade molding 352 within the blade collar ring molding 348 while allowing the blade molding 352 to rotate freely within the chamber 2104. Thus, the blade molding 352 and the blade collar ring molding 348 are free to rotate concentrically.

[0095] Once the blade collar ring molding 348 and the blade molding 352 are assembled, the blade 340 can be assembled as shown in Fig. 24a-c. In this regard, the blade molding 352 includes a T-shaped opening 2300 extending along its length and shaped to receive both the blade 340 and the drive shaft 316, as shown in Fig. 23 shown.

[0096] The proximal end of the blade 340 includes an engagement element 2102 that extends further than the general profile of the remainder of the blade 340, that is, it does not lie in the same axial plane. As shown in Fig. As shown in Figure 24c, the body portion 362 further includes a recess 2100 in which the engagement element 2102 is retained. To facilitate positioning, the proximal end of the blade 340 is cut at a first point opposite the engagement element 2102 to provide a beveled edge 2400 and is cut at a second point adjacent the engagement element 2102 to provide a recessed portion 2402. Thus, the proximal end of the blade 340 has an L-shaped profile.

[0097] In order to arrange the blade 340 in the arrangement of blade molding 352 and blade collar ring molding 348, the blade 340 is aligned at an angle to the longitudinal axis of the instrument 1 opposite the T-shaped opening 2300 such that the engagement element 2102 and the beveled edge 2400 can be introduced into the inner cavity 2404 of the blade molding 352, as in Fig. 24a-b. Then, the blade 340 is pulled downward in line with the longitudinal axis to press the engagement element 2102 into the recess 2100, as shown in Fig. 24c. Thus, the engagement element 2102 is effectively engaged with the shoulder 2406 of the blade molding 352, thereby retaining the proximal end of the blade 340 within the internal cavity 2404.

[0098] The drive shaft 316 can then be inserted through the T-shaped opening 2300 with the blade 340 received in the central track 342 as shown by Fig. 22 and Fig. 23. Thus, longitudinal movement of the assembly of blade collar ring molding 348 and blade molding 352 along drive shaft 316 displaces blade 340 along path 342.

[0099] To complete the blade trigger assembly, a tension spring 350 extends between the blade collar ring molding 348 and the drive arm 2000, for example, by means of hooks 2002, 2004.

[0100] When in use, the user pulls the trigger 24 back to the housing 20 as shown in Fig. 25b-c, such that the drive arm 2000 is pivoted about the first pivot point A. This forces the second pivot point B forward in the distal direction, causing the drive molding 346 to force the assembly of blade collar ring molding 348 and blade molding 352 along the drive shaft. The load exerted on the trigger 24 is therefore transferred via the trigger molding 344 and the drive molding 346 to the blade collar ring molding 348 and the blade molding 352. Because the proximal end of the blade 340 is retained in the blade molding 352, as described above, the blade 340 slides along the central track 342 with the assembly of the blade collar ring molding 348 and the blade molding 352. Because the blade molding 352 is rotationally isolated within the blade collar ring molding 348, the drive shaft 316 can also be rotated without affecting the operation of the cutting mechanism.

[0101] The operation of the mechanism is optimized to provide a good mechanical advantage at the beginning of the path of the blade 340, when the user's finger is extended and less powerful, and also at the end of the path of the blade 340, where more forces act against the path of the blade 340, such as the force of the spring 350, friction within the track 342, and the force required to penetrate thick tissue. As can be seen from Fig. As can be seen in Figure 27, a constant force is exerted by the user on the trigger 24. The mechanism converts this trigger force into a high output force of the blade 340, which decreases as the blade 340 is translated along the path 342 and increases again when the blade 340 reaches the jaws 14. Therefore, when the pivot point B moves from its retracted position to its extended position, as shown in Fig. 28a-b, such that β > 90°, the speed at which the blade collar ring 348 and the blade molding 352 are translated along the drive shaft 316 increases, thereby increasing the force of the blade 340. Thus, the mechanism is capable of advancing the blade 340 with sufficient force to effectively cut the tissue clamped between the jaws 14 without the user having to apply additional force to the trigger 24.

[0102] Furthermore, the cutting mechanism may require the blade 340 to move around a curved set of jaws 14, which increases the frictional forces acting against the path of the blade 340. The frictional force is a product of the coefficient of friction of the blade 340 within the path 342 and the force due to the flexion that the blade 340 exerts on the walls of the path 342.

[0103] To reduce this frictional force, the lateral flexibility of the distal end of the blade may be graded. Such graded flexibility may be achieved, for example, by preferably weakening the blade 340 such that it is able to bend along the path 342 while remaining rigid in the direction of the cutting force. A preferred weakening may be achieved, for example, by providing one or more openings or one or more slots 354 in the distal end, as shown in Fig. 47a. Such openings may be of constant or varying size or shape, depending on the required degree of flexibility. For example, in Fig. 47b, two adjacent openings 4702, 4704 of different sizes are provided, with the larger opening 4702 providing a higher degree of flexibility than the smaller opening 4704. As a further example, in Fig. 47c, three openings 4706, 4708, 4710 of varying size and shape are provided, with the largest opening 4706 being the most distal to provide increased flexibility in this region. A preferred weakening may be further achieved by graduating the thickness of the blade 340 such that the distal end of the blade 340 is beveled 4700, as shown in Fig. 47d shown.

[0104] Alternatively, patterned laser cuts 4702 or chemical etchings in the distal end may be used to control the flexural strength over a length of the blade 340, as shown in Fig. 47e, whereby the distance between such cuts can be constant or increase gradually from the distal to the proximal end.

[0105] Preferably, the blade 340 is divided into at least three regions of varying flexibility, for example, a distal region, a middle region, and a proximal region, with the distal region having greater lateral flexibility than the middle region, and the middle region having greater flexibility than the proximal region. For example, the distal region may be formed from a beveled end 4700 to provide the greatest degree of flexibility; the middle region may be formed from an opening 354 to provide a relatively lesser degree of flexibility; and the proximal region may be formed from a solid rod to provide even less flexibility, as in Fig. 47a. In another, in Fig. In the example shown in Figure 47b, the distal region includes a large opening 4702 to provide the greatest degree of flexibility; the middle region includes a smaller opening 4704 to provide reduced flexibility; and the proximal region is again a solid rod with the least degree of flexibility. The distal region, the middle region, and the proximal region can be obtained using any suitable combination of the preferred weakening described above.

[0106] Another way to reduce the frictional force due to the curved path is to apply a low-friction coating to at least one side of the distal end of the blade 340. For example, the blade may be coated, for example, using physical vapor deposition (PVD) or chemical vapor deposition (CVD) processes with a low-friction or non-stick material, such as a PTFE composite or other low-friction polymer composite. 5. Drainage openings

[0107] Various further features and aspects relating to the structure of the drive shaft 316 will now be described. As described above, the drive shaft 316 is an elongated rod having a T-shaped cross-section, as shown in Fig. 10a. The drive shaft 316 includes a slot or track 342 along its length, which is adapted to receive another elongated member, such as the cutting blade 340 used in the cutting mechanism described above. In use, the cutting blade 340 is caused to slide along the length of the drive shaft 316 to displace the distal end of the cutting blade 340 between the jaws 14 to cut tissue clamped therebetween.

[0108] Over time, blood and tissue can accumulate in the distal end of the instrument 1, particularly along the length of the outer shaft 12 and the drive shaft 316. This accumulation of blood and tissue can cause the blade 340 to stick in the drive shaft 316, reducing the functionality of the instrument 1, particularly the cutting mechanism. To prevent this, portions of the distal end of the drive shaft 318 are cut out to reduce the contact area between the drive shaft 316 and the blade 340, and thus the surface area to which blood and tissue can stick.

[0109] These cut-out sections can create openings such as those in Fig. 10b-c, such that the distal end of the drive shaft 316 includes a base support with bifurcated sidewalls. The cutout portions may also extend to the base of the drive shaft 316 such that the distal end includes bifurcated sidewalls and an open bottom. To maximize the amount of drainage provided by these openings 1000, 1002, the openings preferably constitute more than 50% of the depth of the drive shaft 316.

[0110] Thus, these openings 1000, 1002 provide drainage openings between the central track 342 and the exterior of the drive shaft 316. 6. Rotary wheel and switch

[0111] Various further features and aspects relating to the operation of the thumbwheel 28 (also referred to herein as the rotary wheel) will now be described. The thumbwheel 28 is provided to allow the user to rotate the outer shaft 12 upon which the end effector assembly 14 is mounted. To reduce the required space and thus create a more compact instrument, the internal volume 1300 of the thumbwheel 28 is also used to provide movement space for the inner molded part 314, which forms part of the clamping mechanism described above. With such an arrangement, a more compact mechanism can be obtained.

[0112] In more detail, the rotary wheel 28 (also referred to herein as the thumbwheel) comprises a tooth-like plastic wheel having a plurality of notched portions 336 arranged around its outer diameter. The thumbwheel 28 has the appearance of a gear, with the notched, cut-out portions arranged to ergonomically accommodate a user's thumb. In this regard, and as shown in Fig. 13a, Fig. 13b, especially in Fig. 14a, the notched portions, when in use, are at an angle to the rotational plane of the adjustment wheel, so that, in general, the adjustment wheel or rotary wheel 28 has a slightly frustoconical shape that is wider at an end distal to the user than at the end proximal to the user. The notched portions 336 each extend from the distal edge of the adjustment wheel to the proximal edge and are curved or saddle-like in shape to accommodate a user's thumb when in use. As detailed in Fig. 14a, the angular shape of the notched portions 336 to provide the frustoconical shape of the rotary wheel 28 generally matches the angle of the body portion of the instrument. Fig. In Figure 14a, the dashed lines illustrate the angular shape of the notches 336 around the edge of the wheel 28, which can be considered tangent to the angle of the instrument's outer walls at the point around the wheel, and particularly the portion of the instrument's outer walls immediately in front of the wheel in a distal direction. Such an arrangement, in which the angled notches of the outer edge of the rotary wheel match the angle of the instrument's wall around the wheel, provides a comfortable and ergonomic shape that is easy to use by the surgeon.

[0113] With respect to the number of notched portions 336 around the outer diameter of the wheel 28, as shown in one embodiment, eight notched portions are evenly spaced around the outer diameter of the wheel. In other embodiments, a fewer or greater number of notched portions may be used, for example, as few as six or seven, or as many as nine or ten. If a larger wheel 28 is to be employed, a greater number of notched portions 336 may be included; conversely, if a smaller wheel is to be employed, the number of portions may be fewer. In this regard, the actual size of each notched portion 336 should typically remain the same, as the notched portions are ergonomically selected to comfortably accommodate a user's thumb.

[0114] Regarding the positioning of the adjusting wheel 28 within the instrument, as shown in Fig. 2, the rotary or adjusting wheel 28 is positioned vertically aligned below the switch 26 and is spaced from the adjusting wheel in a direction orthogonal to a longitudinal axis, which is defined, for example, by the longitudinal direction of the drive shaft 316. In particular, the hand switch 26 lies directly on an axis orthogonal to this longitudinal axis and which also passes through the adjusting wheel 28. Furthermore, as shown in Fig. 14a and Fig. 14b, the switch 26 is relatively large and extends above the setting wheel from one side of the upper surface of the instrument to the other. The switch 26 is curved in nature, generally to match the curved upper surface of the outer wall of the instrument, and has ridges, grooves, or other raised projections on its outer surface to assist the user in grasping the switch for depressing it with their thumb. The surface area of ​​the switch 26 is relatively large, namely more than 3 cm. 2 or even 5 cm 2This provides a large surface area to allow ergonomic activation by the user. The vertical orientation of switch 26 directly above control wheel 28 also allows ergonomic activation. As explained elsewhere, switch 26, when in use, serves to cause an RF coagulation signal to be delivered to the end effector for coagulating tissue therein.

[0115] Regarding the ergonomics of the switch and the adjustment wheel, Fig. 35a and Fig. 35b shows two corresponding representations of different users with hands of different sizes. As shown, the switch 26, because it has a relatively large surface area, is easy to operate by users with hands of different sizes while simultaneously operating the clamp handle 22 (and the blade trigger 24, if desired).

[0116] Back to Fig. 12, as previously described, the adjusting wheel 28 has an internal cavity 1300 which, in use, is received within the inner mold part 314. As previously described, the inner mold part 314 includes an internal mold chamber 610 and has a T-shaped severed portion 1208 therein through which the drive shaft 316 is received and secured, as previously described. The inner mold part 314 is snap-fitted into the internal cavity of the wheel 28, and flanges 1206, as in Fig. 12 and Fig. 29a and Fig. 29b, are provided around the outer edge of the cylindrical inner cavity 1300 of the adjusting wheel 28 to hold the inner mold part 314 in place within the cavity once it is inserted therein. The inner cavity 1300 of the adjusting wheel 28 is further provided with locking elements 1200 that interact with corresponding locking elements 1202 provided around the outer periphery of the inner cylindrical mold part 314. The respective locking elements 1200 and 1202 include corresponding raised step portions that fit side-by-side circumferentially around the inner surface of the cavity 1300 when the adjusting wheel 28 and the inner cylindrical mold part 314 are in the correct rotational alignment with respect to one another.The respective locking elements 1200 and 1202 are provided so that, in use, the inner cylindrical molding 314 can slide from side to side within the interior cavity of the wheel 28, but cannot rotate within the wheel 28. Instead, the interacting locking elements 1202 and 1200 act such that the inner molding 314 rotates with the rotating wheel 28 when the latter is rotated. In this way, any torque imparted to the rotating wheel 28 by the user 28 is transferred to the inner molding 314 and then to the drive shaft 316 to rotate the drive shaft supporting the end effector. Fig. 29a and Fig. 29b show the inner mold part 314 inserted into the inner cavity of the adjusting wheel 28 and illustrate how the inner mold part 314 can slide axially within the inner cavity 1300 of the wheel 28.

[0117] Fig. 13a and Fig. 13b further illustrate in greater detail how the inner mold member 314 is capable of moving within the inner cavity 1300 of the wheel 28. As described above, the drive shaft 316 passes through the T-shaped opening 1208 in the inner mold member 314 and is secured therein via projecting snap, locking, or latching elements 602 provided on the end of the drive shaft. The latching or locking elements 602 are in the form of spring-loaded metal engagement elements that are also capable of passing through the T-shaped opening 1208 within the inner mold member 314 and are then received within a second channel portion 606 of the inner mold member, forming a cavity that allows the spring engagement elements to spring apart, thereby securing the drive shaft within the inner mold member.The inner mold part 314 is then pressed into the inner cavity of the adjusting wheel 1208 and held in place by the snap-engaging projections 1206, as described above. The inner mold part can move axially within the inner cavity 1300 to engage the inner surface of the distal wall of the wheel 28, as shown in FIG. Fig. 13a, or, at its opposite end of extension, into abutment against the engagement elements 1206 on the distal edge of the wheel. Thus, the inner mold part 314 is provided with a degree of axial sliding movement within the cavity of the adjusting wheel 28 required as part of the mechanism for controlling the force applied by the user to material contained within the jaws, as described above.

[0118] The snap-fit ​​nature of the inner molded part 314 in the inner cavity of the adjusting wheel 28 greatly improves the assembly of the device, making assembly of the device significantly easier and therefore cheaper. To position the adjusting wheel in the housing, as shown in Fig. As shown in Figure 33, the outer distal wall 1310 of the adjusting wheel 28 is concentric with and flush with an inner support wall 1320 provided as a projection from the housing of the device. This also allows for easy and accurate assembly and positioning of the wheel 28 within the housing. 7. Rotation control of the drive shaft

[0119] As explained above, the shaft 12 with the end effector 14 thereon is rotatable to allow the end effector to be moved to desired rotational positions for cutting and coagulating tissue. However, to prevent the wiring connections to the end effector from being overstressed by excessive rotation of the shaft in one direction, causing the wiring to become coiled, twisted, or subjected to excessive stress, a mechanism for controlling the rotation of the shaft 12 is required, specifically to limit the extent of rotation and thus prevent excessive stress on the wiring. Furthermore, positive control of the rotation of the shaft 12 improves the ergonomic experience of using the instrument and enhances the user's perception of quality.

[0120] To provide rotation control of the shaft in one embodiment, an arrangement shown in Fig. 15a and Fig. 15b and Fig. 16a to 16d. With respect to Fig. 15, the adjusting wheel 28 is provided with notched portions 36 on its proximal surface (i.e., rear surface facing the user) with a ring 1506 projecting slightly from the proximal surface concentrically aligned with the axis of the wheel 28. The ring 1506 rests, in use, on guide stop members 1502 and 1504, which are projections from the inner surface of the outer housing that project upwardly to contact the outer periphery of the ring 1506. The stop member 1502 is smaller than the stop member 1504 due to their positioning on the housing with respect to the axis of the ring, but both stop members 1502 and 1504 have angled upper guide surfaces 1510 and 1512, respectively (see Fig. 15a) which are in contact with the outer peripheral surface of the ring 1506, which forms part of the adjusting wheel, and help to support and guide the adjusting wheel during its rotation.

[0121] In addition to providing a guiding function, the stop members 1502 and 1504 also function as a stop member to prevent rotation of the adjusting wheel beyond the angular position of the stop members. To this end, the ring 1506 is provided with a rectangular stop projection 1500 extending radially therefrom. When the adjusting wheel 28 is rotated, the stop projection 1500 abuts against corresponding stop surfaces 1514 and 1516 of the stop members 1502 and 1504. The stop surfaces are angled to be parallel to the rectangular stop projection 1500 when the stop position is angularly positioned to abut against it.

[0122] The stop members 1502 and 1504 arranged as described above are positioned and of such a length that they provide a known amount of rotation of the wheel 28 from the stop member 1500 to the stop element 1502. In the presently described and in Fig. 15a and Fig. In the arrangement shown in Figure 15b, the stop members 1502 and 1504 are positioned on the housing with a spacing therebetween to allow the thumbwheel to rotate 270° from stop to stop. The extent of rotation can be easily varied by increasing or decreasing the spacing between the stop members, with the stop members being adjusted accordingly in terms of the length and angle of the guide and stop surfaces to substantially normally meet the thumbwheel and the stop members, respectively. For example, the stop members can be positioned and shaped to provide an angular rotation of the thumbwheel between 250° and 300°.

[0123] The above describes the rotation control applied to the adjusting wheel (and then, via the adjusting wheel, the shaft). Fig. 16a to 16d show another rotation control mechanism applied to the shaft at the opposite end of the shaft using the waveform member 320. Here, the waveform member is provided with a rectangular stop member 1600 projecting therefrom. The inner surface of the outer housing is further provided with corresponding shaped stop members 1602 and 1604, shown in the form of a step-like member, which provide corresponding stop surfaces that present corresponding parallel stop surfaces to the rectangular stop member 1600 at corresponding angular positions of the waveform member 320. In the example shown, the shaped stop members are positioned on the housing and present corresponding stop surfaces to the stop member 1600 to allow 270° of rotation of the shaft 12, translating the end effector from stop to stop.In further embodiments, the molded stop portions 1602 and 1604 may be positioned to provide stop surfaces to the stop element 1600 at other rotational angular positions of the molded portion 320 to provide a greater or lesser degree of rotation, for example, from 180° to 360°, or more preferably from 250° to 300°, or most preferably 270°.

[0124] The corresponding rotation control mechanisms provided in the adjusting wheel 28 and in the shaft-forming part 320 can be provided independently of one another, i.e., they do not both have to be provided in a particular embodiment, but rather only one or the other can be provided to provide rotation control of the shaft. However, it is advantageous in terms of operation and qualitative perception of the device if both rotation control mechanisms are provided in one device and are aligned such that they provide stopping of rotation at the correspondingly same points in both directions of rotation. Such an arrangement means that the rotation of the shaft is stopped independently at both ends of the handle section 10, and it becomes very difficult for a user to force further undesired rotation of the shaft beyond the permitted limits set by the stops.

[0125] An alternative rotation control mechanism is in Fig. 36 and Fig. 37 shown. Fig. Figure 36 again shows the waveform part 320, but here the part is provided with a ring 3220 on which are mounted a primary rectangular stop element 3202 extending radially therefrom and secondary position marker elements 3204, 3206, and 3208 arranged substantially equiangularly around the ring, preferably in orthogonal positions. The secondary position marker elements 3204, 3206, and 3208 form small raised projections that are not large enough to engage the stop surfaces 3212 and 3214.

[0126] The stop surfaces 3212 and 3214 are provided as integral molded parts with the outer housing and are positioned here to allow rotation of the waveform part 320 by 180°. In this regard, the stop element 320 comes into contact with the stop surfaces 3212 and 3214 at the ends of the rotation range to prevent further rotation of the waveform part. Thus, as in Fig. 36a to 36c, the shaft member 320 carrying the shaft 12 can rotate through 180° to allow rotational positioning of the end effector as desired.

[0127] Further provided is a sprung projection 3216 comprising a resilient projection of substantially triangular cross-section extending upwardly from the molding-forming stop surface 3214 so that its tip contacts the outer peripheral surface of the ring 3220. The secondary position markers in the form of small, raised projections press against the tip of the sprung projection when the wave-forming part 320 rotates, causing the tip of the sprung projection to move from its rest position to allow the corresponding projection to move past the tip.The effect of this is to provide some user feedback, as the user must apply more force to move the mechanism past the rotational positions where the raised protrusions contact the tip of the spring-loaded protrusion, as sufficient force must be provided for the tip of the spring-loaded protrusion to flex in order for the protrusion to move past the tip. The result is that the user perceives an increase in the force required to rotate the shaft beyond the rotational positions of the raised protrusions, and thus an intuitive indication of the rotational position of the shaft and, hence, of the end effector becomes available to the user. Such a haptic feedback mechanism therefore allows for user-friendly and simple operation of the device.

[0128] Fig. 37 shows the corresponding setting wheel 28 for the mechanism in Fig. 36. Here, the thumbwheel is also provided with respective small stops 3222 arranged orthogonally at 90° intervals around the thumbwheel. A similar mechanism can be provided for the spring-loaded projection 3216 extending from the housing to provide similar haptic feedback as in the case of the shaft-forming part 320. In such an arrangement, haptic feedback regarding the rotational position of the shaft is provided from both ends of the handle, thus improving user perception of the device. 8. Wiring

[0129] At this point, further features and aspects relating to the wiring within the handle 2 will be described. As described above, the switch button 26 is provided to enable and disable the RF signal for operating the electrodes in the end effector assembly 14 via a suitable circuit, for example, via two intrusion-protected switches on a small printed circuit board (PCB) 338. As in Fig. 17, the PCB 338 is connected to a connecting cord 1700 for receiving the RF output from a generator (not shown) and electrical wiring 1702, 1704 for providing the RF current to the electrodes in the jaws 14, for example, one wire for the active electrode and one for the counter electrode.

[0130] In the arrangement, the wiring 1702, 1704 is guided from the electrodes down the outer shaft 12, along the drive shaft 316 and up to the shaft forming part 320, as shown by Fig. 17. As shown in Fig. As shown in Figure 9b, the shaft member 320 is a cylindrical or barrel-shaped component with an opening 912 at the distal end to receive the outer shaft 12. The outer shaft 12 is secured to the shaft member 320, for example, by snap-engagement projections 900 that cooperate with corresponding grooves 902 in the shaft member 320. Consequently, when the shaft member 320 rotates, the outer shaft 12 rotates with it. The shaft member 320 further includes a further opening 914 at the proximal end, the opening 914 having a T-shape to receive the drive shaft 316, which extends through the internal cavity 1802 of the shaft member 320 and down the length of the outer shaft 12. Thus, the drive shaft 316 is able to slide within the shaft portion 320 and the outer shaft 12, but any rotational movement of the drive shaft 316 is transmitted to the shaft portion 320 and subsequently the outer shaft 12.

[0131] As in Fig. As shown in Figure 18a, the electrode wires 1702, 1704 are guided from the inner cavity 1802 through an opening 1800 in the wall of the waveform member 320 before being wrapped over and around the body portion 1804 of the waveform member 320. Wrapping the wires 1702, 1704 around the waveform member 320 in this manner keeps the wires 1702, 1704 in a compact arrangement to prevent the wires 1702, 1704 from interfering with the assembly of the rest of the instrument 1. Furthermore, the winding of the wires 1702, 1704 around the waveform part 320 means that when the waveform part 320 rotates with the drive shaft 316, the wires 1702, 1704 roll up and down with the rotation without the wires 1702, 1702 being overstretched and thereby short-circuited. In particular, the winding of the wires 1702, 1704 in this particular manner allows up to 270° of rotation, as described with respect to Fig. 15a-b and Fig. 16a-d.

[0132] The electrical wiring 1702, 1704 is then routed along the top of the housing 20. In this regard, one of the shell moldings 300 is provided with two compartments 1900, 1902 arranged side by side to receive the wire contacts 1904, 1906 that connect the active and return wires 1702, 1704 to the wiring 1908, 1910 of the intrusion-resistant switches 338. All electrical wires 1702, 1704, 1908, 1910 are routed into and around the compartments 1900, 1902, such that only one contact 1904, 1906 is accommodated in each compartment 1900, 1902. Routing of the wires may be facilitated by guide sections 1912, 1914, 1916 that guide a set of wires 1702, 1910 around the exterior of compartments 1900, 1902. In each compartment, the respective active wire 1702 is longitudinally aligned with wire 1908, and the return wire 1704 is longitudinally aligned with wire 1910.

[0133] Consequently, the two wire contacts 1904, 1906 are longitudinally separated so that only one contact can pass through each compartment 1900, 1902, thereby providing a physical barrier between each contact 1904, 1906 and the wiring. This eliminates the risk of insulation damage to one of the wires by the contacts 1904, 1906 themselves.

[0134] The wires 1702, 1704, 1908, 1708 are all inserted into their respective compartments 1900, 1902 via small openings 1918, 1920, 1922, 1924 in the compartment walls. Preferably, the dimensions of the openings 1918, 1920, 1922, 1924 are such that only one electrical wire can pass through. The opposing shell molding 302 also includes corresponding rib members (not shown) to retain the contacts 1904, 1906 in the compartments 1900, 1902, forming a substantially sealed housing. This is important to minimize the permeability of the compartments 1900, 1920 to protect the contacts 1904, 1906 from any fluid that could penetrate down the outer shaft 12 and into the housing 20, which would cause a short-circuit of the contacts 1904, 1906. 9. End effector arrangements

[0135] Exemplary end effector arrangements that can be used with the device will now be described. The examples to be described are mentioned only for the sake of completeness, and it is understood that other end effector designs can be used with the instrument, provided they are capable of being driven by the drive shaft 316. That is, embodiments of the invention are not limited to the specific end effectors described herein, but other end effector designs can also be used.

[0136] Fig. 38 to 44 show exemplary instruments in which electrically conductive stop elements are arranged on one or both of the sealing electrodes. With respect to Fig. 38, an end effector, generally designated 3801, comprises an upper jaw 3802 pivotally connected to a lower jaw 3803 about a pivot point 3804. Flanges 3805 are provided at the proximal end of the upper jaw 3802, while flanges 3806 are provided at the proximal end of the lower jaw 3803. The flanges 3805 and 3806 each have slots 3807 through which a drive pin 3808 extends, such that proximal and distal movement of the drive pin 3808 (via a drive mechanism (not shown)) causes the jaws 3802, 3803 to pivot between an open and a closed position.

[0137] A metallic clamp 3809 is provided on the inner surface of the upper jaw 3802, while a metallic clamp 3810 is provided on the inner surface of the lower jaw 3803. When the jaws 3802, 3803 pivot to their closed positions, the metallic clamps 3809, 3810 come close to each other to grasp tissue (not shown) between them.

[0138] The upper clamp 3809 has a generally planar surface, except for an elongated depression (in Fig. 38 not visible) running along its length. The lower clamping piece 3810 has a corresponding recess 3811, wherein the recesses in the clamping pieces 3809, 3810 accommodate the longitudinal movement of a cutting blade (not shown). The lower clamping piece 3810 is further provided with a plurality of metallic stop elements 3812 arranged along the length of the clamping piece and on both sides of the recess 3811. The stop elements 3812 will now be described with reference to Fig. 39 and Fig. 40 will be described in more detail.

[0139] Each metallic stop element 3812 consists of the upper bulge of a stop element 3813 received in an insulating element 3814 so as to enclose the stop element, isolating it from the rest of the clamping piece 3810. Each insulating element 3814 and stop element 3813 is disposed in a corresponding opening 3851 provided in the clamping piece 3810, so that the upper portion of the insulating element forms an insulating ring 3816 around each stop element 3812.

[0140] When the clamping jaws 3802, 3803 are moved to their closed position (as in Fig. 40), the stop elements 3812 contact the upper clamp 3809, maintaining a separation between the upper and lower clamps of between 20µm and approximately 350µm (0.00079 inches to approximately 0.014 inches). In use, an electrosurgical coagulation voltage is applied between the clamps 3809, 3810, and the separation between the clamps ensures effective sealing of tissue grasped between the jaws 3802, 3803. At the same time, electrical shorting between the clamps is prevented because the stop elements 3812 are electrically insulated so that they do not carry the same electrical potential as the rest of the clamp 3810.The metallic stop elements 3812 are rigid, allowing consistent separation of the surfaces of the clamping pieces, while it is feasible for the electrical potential of the stop elements 3813 to be monitored to detect when they contact the upper clamping piece 3809 to indicate the closing of the clamping jaws.

[0141] Fig. 41 to 43 show an alternative arrangement in which the metallic stop elements 3812 are mounted directly on the lower clamping piece 3810, without the insulating elements surrounding the stop elements. In this arrangement, insulating elements 3817 are provided on the upper clamping piece 3809 in corresponding relationship to each of the stop elements. In this manner, when the jaws 3802, 3803 are closed, the insulating elements 3817 ensure that no electrical shorting occurs between the upper clamping piece 3809 and the lower clamping piece 3810. The metallic stop elements 3812 ensure that the appropriate separation of the jaws is maintained during the application of electrosurgical energy to seal tissue grasped between the jaws.

[0142] Fig. 44 finally shows a further alternative in which the metallic stop elements 3812 are again mounted directly on the lower clamping piece 3810. In this arrangement, a metallic counter-holder 3818 is arranged opposite each stop element, wherein each metallic counter-holder 3818 is surrounded by an insulating element 3819 in order to be insulated from the rest of the upper clamping piece 3809. When the clamping jaws are closed, metal-to-metal contact occurs between the stop elements 3812 and the metallic counter-holders 3818, wherein the insulation of the counter-holders ensures that electrical short-circuiting between the clamping pieces 3809, 3810 is again prevented. Here, too, the electrical potential of each of the metallic counter-holders can be monitored to detect when they assume the potential of the lower clamping piece, which indicates the closing of the clamping jaws. 10. Electrosurgical system

[0143] With reference to Fig. 45, the instrument 1 is provided, in use, to be connected to an electrosurgical generator 4500 having a controllable radio frequency (RF) source therein (not shown) which, in use, generates an RF coagulation signal that coagulates or seals tissue when applied thereto via the electrodes of the end effector of the instrument 1. The electrosurgical generator 4500 includes control input switches 4504 and 4502 to respectively allow the generator to be turned on and off and to allow controlling the power of the RF coagulation signal delivered to the instrument 1. In this respect, the electrosurgical generator 4500 is conventional.

[0144] The instrument 1, in use, is connected to the generator 4500 by a control and power supply line 4506, which includes separate electrical lines to allow delivery of an RF signal to the end effector of the instrument 1 via the previously described internal wiring, and further to allow receipt of a control signal from the switch 26 of the instrument 1 to cause the electrosurgical generator to output an RF coagulation signal for the instrument 1. In use, the surgeon activates the generator via an on / off switch 4504 and selects the coagulation or sealing signal strength to be generated by the internal RF source using knobs 4502.During a surgical procedure with the instrument, when a sealing or coagulation RF signal is required at the end effector, the surgeon controls the generator to generate such a signal by pressing the instrument's switch 26. The generated RF signal is then passed to the end effector via electrical leads 4506. That is, pressing the switch 26 in use causes the delivery of an RF coagulation or sealing signal to the appropriate electrodes contained in the end effector. 11. Summary

[0145] In light of the above, embodiments of the invention therefore provide an advanced electrosurgical forceps instrument that allows for simple and ergonomic one-handed operation by the user, provides rotational flexibility of the end effector, controls the force applied by the end effector to the grasped tissue to prevent excessive force from being applied, and allows for convenient mechanical cutting of the grasped tissue while simultaneously providing electrosurgical coagulation or sealing of the tissue. Furthermore, the instrument was designed to be easily and inexpensively assembled while simultaneously providing a compact instrument thanks to efficient use of the available space in its internal activation mechanism.

[0146] Various further modifications to the above-described embodiments, whether by addition, elimination, or substitution, will be apparent to those skilled in the art to provide additional embodiments, each of which, in its entirety, is within the scope of the appended claims.

Claims

[1] A locking mechanism for the handle (10) of a surgical instrument (1), the handle (10) comprising a housing (20) and an actuating element movable with respect to the housing (20) between a first and a second position to actuate an end effector (14), the locking mechanism comprising: a protruding element (324) arranged on the actuating element; and a single, integrally formed snap-in molding (326) disposed in the housing (20), the snap-in molding (326) comprising: i) a body portion (1108) slidably disposed in a channel (1110) in the housing (20), the body portion (1108) comprising guide means defining first and second paths and a groove (1114) therebetween, the projecting member (324) being arranged, in use, to traverse the first path when the actuating member is moved from the first position towards the second position and to traverse the second path when the actuating member is moved from the second position towards the first position; ii) a locking rod (4602) extending from the body portion (1108) and movable between a first and a second position by a user of the surgical instrument (1) to manually slide the body portion (1108) within the channel (1110) in the handle (10); and iii) a spring element (1104) for biasing the body portion (1108) in the channel (1110) in a direction such that the projecting element (324) is received in the groove (1114) when the actuating element is in the second position. [2] The latching mechanism of claim 1, wherein the latching molding (326) further comprises an override button (4600), the override button (4600) being integrally formed in a position on the body portion (1108) and movable to change the position of the guide means to allow the protruding member (324) to exit the groove (1114) and consequently to allow the actuating member to return to the first position. [3] A latching mechanism according to claim 1 or 2, wherein the guide means comprises a substantially V-shaped molded projection (1106), the first and second paths being formed by opposite sides of the projection (1106). [4] The locking mechanism according to claim 3, wherein the groove (1114) is formed in the top of the V-shaped projection (1106). [5] A latching mechanism according to any one of the preceding claims, wherein the projecting member (324) comprises a pin (1120). [6] The latching mechanism of claim 5, wherein the pin (1120) is mounted on a cantilever arm (1118) extending from the actuator. [7] A latching mechanism according to any one of the preceding claims, wherein the spring element (1104) comprises a curved element arranged at one end of the body portion (1108). [8] A latching mechanism according to any preceding claim, wherein the latching molding (326) is such that when the locking bar (4602) is moved to its second position, the protruding member (324) engages the second path instead of the first path when the actuating member is moved to its second position. [9] The latching mechanism of claim 8, wherein the latching molding (326) is such that the protruding member (324) is never received in the groove (1114) when the locking bar (4602) is in its second position. [10] Surgical instrument (1), comprising: a handle (10) having a housing (20) and an actuating element movable relative to the housing (20) between a first and a second position; an end effector (14) movable between a first and a second state in response to the relative movement of the actuating element; and a locking mechanism according to one of claims 1 to 9. [11] Surgical instrument according to claim 10, wherein the end effector (14) comprises a first and a second clamping jaw (14). [12] A surgical instrument according to claim 11, wherein the first and second states of the end effector (14) comprise an open and a closed position for the jaws (14). [13] A surgical instrument according to any one of claims 10 to 12, wherein the handle (10) further comprises a trigger (24) operable to produce an effect in addition to movement of the end effector (14) between its first and second states. [14] A surgical instrument according to claim 13, wherein the effect actuatable by the trigger (24) comprises the longitudinal displacement of a mechanical cutting blade (340).

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