# Patent

## Title
Method of manufacturing an electrosurgical forceps

## Abstract

A method for manufacturing a jaw assembly configured for use with an electrosurgical forceps is provided. A seal plate with an inwardly facing tab member extending along a peripheral edge thereof is formed. A cavity defined along the inwardly facing tab member of the seal plate is formed. Subsequently, the seal plate is overmolded to a jaw housing. The cavity is configured to receive an insulative substrate therein to facilitate securing the seal plate to the jaw housing.

## Background
BACKGROUND
1. Technical Field
The present disclosure relates to an electrosurgical forceps and, more particularly, to a method of manufacturing an end effector assembly including jaw members with seal plates having inwardly facing tab members formed thereon to facilitate overmolding the seal plates to respective jaw housings of the jaw members.
2. Description of Related Art
Electrosurgical forceps are well known in the medical arts. For example, an electrosurgical endoscopic forceps is utilized in surgical procedures, e.g., laparoscopic surgical procedure, where access to tissue is accomplished through a cannula or other suitable device positioned in an opening on a patient. The endoscopic forceps, typically, includes a housing, a handle assembly including a movable handle, a drive assembly, a shaft and an end effector assembly attached to a distal end of the shaft. Typically, the endoscopic forceps utilizes both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue. In particular, the jaw members operably communicate with the drive assembly to manipulate tissue, e.g., grasp and seal tissue and the jaw members have respective seal plates secured to the jaw housing of the respective jaw members to seal tissue.
As is conventional in the endoscopic forceps art, the seal plates are, typically, secured to the respective jaw housing of the respective jaw members via an overmolding process. In particular, a peripheral edge of the seal plate(s) is bent or folded downwards and, subsequently, bent or folded outwards providing a thin lip or tab (referred to in the art as a “pinch trim”) that is overmolded to the jaw housing. As can be appreciated, this results in a thin section of the overmolding that may deform at the high temperatures that are typically associated with an electrosurgical procedure, e.g., an electrosurgical sealing procedure. This deformation of the overmolding may lead to delamination of the of the seal plate from the jaw housing. The delamination of the seal plate from the jaw housing may increase the likelihood of flexure of the jaw members and/or seal plates, which, in turn, may increase the likelihood of the seal plates inadvertently coming into contact with one another resulting in arcs developing therebetween.
In addition to the foregoing, one or more wires are typically secured to the seal plates of the respective jaw members to provide electrosurgical energy thereto. In particular, one (in the case of monopolar endoscopic forceps configurations) or two (in the case of bipolar endoscopic forceps configurations) wires are secured to the seal plates on the respective jaw members via a crimping process. This crimping process is complex and increases manufacturing costs of the electrosurgical instrument. Moreover, this crimping process, e.g., a crimp-on terminal that is positioned on one or both of the seal plates and connects to the respective jaw wire, takes up a large amount of space in the relatively limited space of the jaw members.
SUMMARY
In view of the foregoing, there exists a need in the art for a method of manufacturing an end effector assembly including jaw members with seal plates having inwardly facing tab members formed thereon to facilitate overmolding the seal plates to respective jaw housings of the jaw members.
Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user.
An aspect of the present disclosure provides method for manufacturing a jaw assembly configured for use with an electrosurgical forceps. A seal plate with an inwardly facing tab member extending along a peripheral edge thereof is formed. In certain instances, a jaw wire may be welded to the seal plate. Subsequently, the seal plate is overmolded to a jaw housing. Forming the seal plate may include forming a cavity defined along the inwardly facing tab member of the seal plate. In this instance, the cavity may be configured to receive an insulative substrate therein to facilitate securing the seal plate to the jaw housing.
The insulative substrate may be made from plastic. Forming the seal plate may include forming one or more apertures thereon. In this instance, the aperture(s) is configured to receive the insulative substrate therein such that during the overmolding process of the jaw housing an insulative stop member is formed on the seal plate. The insulative stop member may include a generally arcuate configuration. Forming the seal plate may include forming a plurality of notches along the inwardly facing tab member of the seal plate.
An aspect of the present disclosure provides a method for manufacturing jaw members configured for use with an electrosurgical forceps. One or more of a pair of seal plates is stamped from a sheet metal. The stamped seal plates are formed with an inwardly facing tab member extending along a peripheral edge thereof. In certain instances, a jaw wire may be welded to each of the seal plates. The seal plates are positioned into respective mold cavities. An insulative substrate is introduced into the respective mold cavities. The insulative substrate is allowed to harden in the respective mold cavities to form respective jaw housings with seal plates secured thereto. Forming the seal plates may include forming a cavity defined along the inwardly facing tab member of the seal plate. In this instance, the cavity may be configured to receive the insulative substrate therein to facilitate securing the seal plates to the respective jaw housing. The jaw housings are removed from the respective mold cavities to form a pair of jaw members. The insulative substrate may be made from plastic.
Forming the seal plates may include forming one or more apertures thereon. The aperture(s) may be configured to receive the insulative substrate therein such that during the overmolding process of the respective jaw housing an insulative stop member is formed on the seal plate. The insulative stop member may include a generally arcuate configuration. Forming the seal plates may include forming a plurality of notches along the inwardly facing tab member of the seal plate.
An aspect of the present disclosure provides a method for manufacturing jaw members configured for use with an electrosurgical forceps. A pair of seal plates is stamped from sheet metal. The stamped seal plates may be formed with an inwardly facing tab member extending along a peripheral edge thereof, and one or more apertures thereon. A cavity defined along the inwardly facing tab member of the seal plate is formed. The seal plates are positioned into respective mold cavities. An insulative substrate is introduced into the respective mold cavities. The insulative substrate is allowed to harden in the respective mold cavities to form respective jaw housings with seal plates secured thereto. The cavities are defined along the inwardly facing tab members of the seal plates and are configured to receive the insulative substrate therein to facilitate securing the seal plates to a respective jaw housing. The aperture(s) is configured to receive the insulative substrate therein such that an insulative stop member is formed on the seal plate. The jaw housings is removed from the respective mold cavities to form a pair of jaw members.



BRIEF DESCRIPTION OF THE DRAWING
Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein:
FIG. 1 is a perspective view of an endoscopic electrosurgical forceps utilizing an end effector including jaw members manufactured according to an embodiment of the present disclosure;
FIG. 2 is a cross-sectional view of a pair of opposing seal plates of the jaw members depicted in FIG. 1 with a corresponding jaw housings illustrated in phantom;
FIG. 3 is a plan view of the lower seal plate depicted in FIG. 2 illustrating a connection point between the seal plate and a jaw wire of the endoscopic electrosurgical forceps;
FIG. 4 a plan view of a seal plate configured for use with the jaw members depicted in FIG. 1 according to an embodiment of the present disclosure;
FIG. 5 is a cross-sectional view of the seal plate depicted in FIG. 4 taken along line segment 5-5 with the corresponding jaw housing illustrated in phantom; and
FIG. 6 is a plan view of a seal plate configured for use with the jaw members depicted in FIG. 1 according to another embodiment of the present disclosure.



DETAILED DESCRIPTION
Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
Turning now to FIG. 1, an electrosurgical endoscopic forceps 10 (forceps 10) is provided having a longitudinal axis “A-A” defined therethrough, a housing 20, a handle assembly 30, a rotating assembly 70, a trigger assembly 80 and an end effector assembly 100. Forceps 10 further includes a shaft 12 having a distal end 14 configured to mechanically engage end effector assembly 100 and a proximal end 16 that mechanically engages housing 20. Forceps 10 also includes electrosurgical cable 610 that connects forceps 10 to a generator (not shown) or other suitable power source. Alternately, forceps 10 may be configured as a battery powered instrument. Cable 610 includes one or more wires 611 (one wire shown in the drawings) extending therethrough that has sufficient length to extend through shaft 12 in order to provide electrical energy to one or both of the jaw members 110 and 120 of end effector assembly 100.
Continuing with reference to FIG. 1, end effector assembly 100 is designed as a unilateral assembly, e.g., where jaw member 120 is fixed relative to shaft 12 and jaw member 110 is moveable about pivot 103 relative to shaft 12 and fixed jaw member 120. However, end effector assembly 100 may alternatively be configured as a bilateral assembly, e.g., where both jaw member 110 and jaw member 120 are moveable about a pivot 103 relative to one another and to shaft 12. In some embodiments, a knife assembly (not explicitly shown) is disposed within shaft 12 and a knife channel (not explicitly shown) is defined within one or both jaw members 110, 120 to permit reciprocation of a knife blade (not explicitly shown) therethrough, e.g., via an activation of trigger 82 (FIG. 1) of trigger assembly 80.
Other than jaw member 110 being movable and jaw member 120 being stationary, jaw members 110 and 120 are identical to one another. In view thereof, and unless otherwise noted, jaw member 120 is described in detail hereinafter.
Turning now to FIG. 2, jaw member 120 is illustrated including a jaw housing 124 (shown in phantom). Jaw housing 124 may be made from any suitable material including, but not limited to, plastic (e.g., thermoplastic, thermosetting plastic, etc.), ceramic material, etc. In the illustrated embodiment, jaw housing 124 is made from thermosetting plastic that serves as an insulative substrate, described in more detail below. In certain instances, it may prove advantageous to provide an exterior portion of the jaw housing 124 that is made from metal and an interior portion (e.g., a portion that is configured to support the seal plate 122 thereon) of the jaw housing 124 that made from plastic. In this instance, the interior portion serves as an insulative barrier between the seal plate 122 and the exterior portion of the jaw housing 124.
Continuing with reference to FIG. 2, jaw member 120 includes electrically conductive tissue sealing plate 122. Seal plate 122 may be made via any suitable manufacturing process including a machining process, a stamping process or the like. In the illustrated embodiment seal plate 122 is made via a stamping process and, subsequently, overmolded to jaw housing 124. A stamping or machine press (not shown) may be utilized to cut or “punch” sheet-metal to a desired configuration. Subsequently, the stamping press is utilized to shape the “punched” sheet-metal into one or more suitable configurations by deforming it with a die or other suitable device (not shown). The aforementioned stamping process may include a variety of other sheet-metal manufacturing processes, such as, for example, blanking, embossing, bending, flanging, and coining.
In accordance with the instant disclosure, the seal plate 122 is formed with an inwardly facing tab member 126 (FIG. 2) that extends along a peripheral edge 128 of the seal plate 122 (FIGS. 2 and 3). Inwardly facing tab member 126 is configured to facilitate securing the seal plate 122 to the jaw housing 124 during a manufacturing process of the jaw member 120. In particular, a cavity or channel 130 (FIG. 2) is defined along the inwardly facing tab 126 member and is configured to receive the liquid thermosetting plastic therein. More particularly, during manufacture of the jaw member 120, seal plate 122 is positioned within a mold cavity (not explicitly shown) that is configured to support the seal plate 122 therein and shaped to correspond to a desired jaw housing configuration. Subsequently, liquid thermosetting plastic is introduced into the mold cavity to form the jaw housing 124. The cavity 130 of the inwardly facing tab member 126 is configured to receive the liquid thermosetting plastic therein such that when the thermosetting plastic cures, the seal plate 122 firmly secures to the formed jaw housing 124.
The liquid thermosetting plastic may be heated and/or mixed prior to being introduced into the mold cavity. A “single-shot” or “two-shot” injection molding process may be utilized to introduce the liquid thermosetting plastic into the mold cavity.
Jaw member 110 includes an opposing electrically conductive tissue sealing plate 112 including an inwardly facing tab member 127 that extends along a peripheral edge 129 of the seal plate 112 (FIG. 2). Similar to that of cavity 130 of inwardly facing tab member 126, a cavity 131 of the inwardly facing tab member 127 facilitates securing the seal plate 112 to a jaw housing 114 (FIG. 2).
With reference to FIG. 3, wire 611 is operably coupled to the seal plate 122. More particularly, and unlike conventional forceps that utilize a crimping process to couple a jaw wire to a seal plate, wire 611 of the forceps 10 is coupled to the seal plate 122 via a spot welding process, ultrasonic welding process or the like. One of these welding processes e.g., spot welding, is utilized to secure wire 611 to the seal plate 122 prior to the seal plate 122 being positioned within the mold cavity. As can be appreciated, this overcomes the aforementioned drawbacks described above with respect to conventional forceps. That is, the spot welding process is an inexpensive and relatively easy manufacturing method that secures the wire 611 to the seal plate 122, as opposed to the crimping process that typically utilizes crimp-on terminals to secure wires to the seal plates of conventional forceps. The aforementioned spot welding process may be utilized to secure another wire (not explicitly shown) to the seal plate 112.
In embodiments, it may prove advantageous to provide one or more insulative or non-conductive stop members on one or both of the seal plates 112 and 122. In accordance with the present disclosure, either of seal plates 112 or 122 may be formed with one or more apertures 132 of suitable configuration (FIG. 4). For illustrative purposes, six (6) apertures 132 are shown formed on seal plate 122. Apertures 132 are configured to receive the liquid thermosetting plastic therein such that during the manufacturing process of the jaw housing 124, an insulative stop member(s) 134 forms on the seal plate 122 of the jaw member 120 (FIG. 5). In particular, during the molding process of the jaw housing 124, the liquefied thermosetting plastic seeps or flows through the apertures 132 and cures on a seal surface of the seal plate 122 as the jaw housing 124 cures. In the illustrated embodiment, the cured stop members 134 include a generally arcuate configuration having a dimple or mushroom like profile (as best see in FIG. 5), although other configurations are contemplated.
The stop members 134 function similar to that of stop members that are typically associated with conventional forceps. That is, the stop members 134 may provide a specific gap distance between the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping configuration. Moreover, the stop members 134 may function to prevent the seal plates 112 and 122 from touching one another during the transmission of electrosurgical energy to the jaw members 110 and 120. In embodiments, the gap distance may range from about 0.001 inches to about 0.0016 inches. Unlike conventional stop members that are typically glued to seal plates via one or more suitable adhesives, and which are prone to becoming dislodged from the seal plates under high shear forces, the stop members 134 of the instant disclosure are formed with the jaw housing 124 and, thus, are permanently affixed to the seal surface of the seal plate 122. Therefore, the likelihood of the stop members 134 becoming dislodged from the seal surface of the seal plate 124 is diminished, if not eliminated.
In embodiment, where each of the seal plates 112 and 122 includes stop members 134, the stop members 134 on the seal plates 112 and 122 may be in vertical registration with one another.
In certain embodiments, after the jaw housing 124 and/or stop members 134 have cured, a buffing machine or the like may be utilized to smooth out rough edges that may have formed during the curing process.
In use, tissue may be positioned between the jaw members 110 and 120. Subsequently, electrosurgical energy is transmitted to the seal plates 112 and 122 via wires 611. The unique configuration of the seal plates 112, 122 including the respective inwardly facing tab members 127, 126 associated therewith overcome the aforementioned drawbacks typically associated with conventional forceps. That is, the inwardly facing tab members 127, 126 including the respective cavities 131, 130 defined therein provides a greater point of contact between the jaw housings 114, 124 and seal plates 112, 122, and, thus, the likelihood of the seal plates 112, 122 delaminating adjacent the point of contact between the seal plates 112, 122 and jaw housings 114, 124 is diminished, if not eliminated.
From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in certain instances, it may prove advantageous to secure the seal plates 112 and 122 to the respective jaw housing 114, 124 of the jaw members 110 and 120 via a different securement method.
With reference to FIG. 6 a plan view of a seal plate according to an alternate embodiment is shown designated as a seal plate 222. Seal plate 222 is similar to that of seal plate 122, however, unlike seal plate 122 that includes an inwardly facing tab member 126, seal plate 222 includes an outwardly facing tab member 226. Unlike conventional seal plates that utilize outwardly facing tab members, outwardly facing tab member 226 includes one or more notches 228. Notches 228 allow for local, thicker wall section (not explicitly shown) that adds strength to the jaw housing (not explicitly shown). As with the cavity 130 defined in the inwardly facing tab member 126, the notches 228 of the outwardly facing tab member 226 are configured to receive the liquid thermosetting plastic therein. When the liquid thermosetting plastic cures, the seal plate 222 is firmly secured to the jaw housing. (from the invention disclosure, it is not readily apparent where the notches are located on the seal plate)
The unique configuration of the seal plate 222 including the outwardly facing tab member 226 associated therewith overcomes the aforementioned drawbacks typically associated with conventional forceps. That is, the outwardly facing tab member 226 including the notches 228 defined therein provide a greater point of contact between the jaw housing and seal plate 222, and, thus, the likelihood of the seal plate 222 delaminating adjacent the point of contact between the seal plate 222 and jaw housing is diminished, if not eliminated.
In another embodiment, one or both of the inwardly facing tab members 126, 127 may include one or more of the notches 228 thereon.
While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

## Claims

1. A method for manufacturing a jaw member configured for use with an electrosurgical forceps, comprising:
forming a seal plate defining a central longitudinal axis and a sealing surface;
forming a cavity opposite the sealing surface by bending a peripheral edge of the seal plate substantially perpendicular to the sealing surface to define a tab and bending a portion of the tab toward the longitudinal axis substantially parallel to the sealing surface, wherein forming the cavity includes forming the cavity between the tab and another portion of the seal plate; and
securing the seal plate to a jaw housing by receiving an insulative substrate within the cavity during an overmolding process to form the jaw member configured for use with an electrosurgical forceps.

2. The method according to claim 1, wherein forming the seal plate includes forming at least one aperture thereon.

3. The method according to claim 2, wherein the at least one aperture is configured to receive the insulative substrate therein such that during the overmolding process of the jaw housing an insulative stop member is formed on the seal plate.

4. The method according to claim 3, wherein the insulative stop member includes a generally arcuate configuration.

5. The method according to claim 1, further comprising welding a wire to the seal plate.

6. The method according to claim 1, wherein the insulative substrate is made from plastic.

7. A method for manufacturing jaw members configured for use with an electrosurgical forceps, comprising:
stamping at least one pair of seal plates from sheet metal, each of the seal plates defining a central longitudinal axis and a sealing surface;
forming, on each of the seal plates, a cavity opposite the sealing surface by bending a peripheral edge of each of the seal plates substantially perpendicular to the sealing surface to define a tab and bending a portion of the tab toward the central longitudinal axis substantially parallel to the sealing surface, wherein forming the cavity includes forming the cavity between the tab and another portion of the seal plate;
positioning the seal plates into respective mold cavities;
introducing an insulative substrate into the respective mold cavities such that the insulative substrate is received within the respective formed cavity;
allowing the insulative substrate to harden in the respective mold cavities to form respective jaw housings with respective seal plates secured thereto, wherein the respective formed cavity is configured to receive the insulative substrate therein to facilitate securing the respective seal plate to the respective jaw housing; and
removing the jaw housings from the respective mold cavities to form at least a pair of jaw members configured for use with an electrosurgical forceps.

8. The method according to claim 7, wherein forming the seal plates includes forming at least one aperture thereon.

9. The method according to claim 8, wherein the at least one aperture is configured to receive the insulative substrate therein such that during an overmolding process of the respective jaw housing an insulative stop member is formed on the seal plate.

10. The method according to claim 9, wherein the insulative stop member includes a generally arcuate configuration.

11. The method according to claim 7, further comprising welding a wire to each of the seal plates.

12. The method according to claim 7, wherein the insulative substrate is made from plastic.

13. A method for manufacturing jaw members configured for use with an electrosurgical forceps, comprising:
stamping at least one pair of seal plates from sheet metal, each of the seal plates defining a central longitudinal axis and a sealing surface;
forming, on each of the seal plates, a cavity opposite the sealing surface by bending a peripheral edge of each of the seal plates substantially perpendicular to the sealing surface to define a tab and bending a portion of the tab toward the central longitudinal axis substantially parallel to the surface, wherein forming the cavity includes forming the cavity between the tab and another portion of the seal plate;
positioning the seal plates into respective mold cavities;
introducing an insulative substrate into each of the respective mold cavities such that the insulative substrate is received within the respective formed cavity;
allowing the insulative substrate to harden in the respective mold cavities to form respective jaw housings with respective seal plates secured thereto, wherein each formed cavity is configured to receive the insulative substrate therein to facilitate securing the respective seal plates to the respective jaw housings, and wherein the at least one aperture is configured to receive the insulative substrate therein such that an insulative stop member is formed on the seal plate; and
removing the jaw housings from the respective mold cavities to form a pair of jaw members configured for use with an electrosurgical forceps.