HK1089071B - Circumferential trocar seal assembly - Google Patents

Description

Annular trocar seal assembly

Technical Field

The present invention relates to a trocar assembly. More particularly, the present invention relates to an annular trocar sealing structure.

Background

A trocar assembly is a surgical instrument used to gain access to a body cavity. Trocar assemblies typically include two main components: a trocar cannula and a trocar obturator which are composed of a trocar shell and a trocar cannula. The trocar cannula is passed directly through the skin to contact the body cavity, and the trocar obturator is inserted in the trocar cannula. Once the body cavity is accessed, laparoscopic or arthroscopic surgery as well as endoscopic procedures may be performed. To pierce the skin, the distal end of the trocar cannula is placed over the skin previously cut with a scalpel, and the trocar obturator is then used to pierce the skin and enter the body cavity. The sharp tip of the obturator is forced through the skin by applying pressure to the proximal end of the obturator until it enters the body cavity. The trocar cannula is inserted through the puncture formed by the trocar obturator and the trocar obturator is withdrawn leaving the trocar cannula as a path into the body cavity.

The proximal end portion of the trocar cannula is typically coupled to a trocar housing that defines a chamber having an open distal end portion in communication with a lumen defined by the trocar cannula. A trocar obturator or other elongated surgical instrument or tool extends axially into and is withdrawn from the trocar cannula through a proximal end portion of a chamber defined by the trocar housing.

Current trocar assemblies are typically designed with a sealing mechanism that is positioned within the chamber of the trocar housing. The sealing mechanism is typically a sealing gasket or pad through which an obturator or other instrument extends. The sealing mechanism seals the outer surface of the inserted instrument and thereby prevents fluid and insufflation gas from exiting through the trocar cannula or entering the body cavity. It is desirable that such seals provide excellent tear resistance, puncture resistance (resistance to snagging), and low friction relative to the inserted device, such as a rod, shaft, or cylinder.

The seal assembly is designed to maintain a seal prior to instrument insertion and after instrument removal. As a result, many trocar assemblies provide a dual seal system. That is, a top or proximal seal is used to seal around the tool/instrument when present and a flapper or duckbill seal is required below the top seal for sealing the trocar cannula when no instrument is present.

In contrast, other trocar assemblies employ a single sealing mechanism. Many of these trocar seal assemblies simply employ silicone seals having a slightly smaller aperture than the smallest tool/instrument used in conjunction with the trocar assembly. This type of seal is often referred to as a lip seal. Surgical instruments of different diameters are passed through the lip seal. As such, these seals are often required to provide a seal for the entire size range of instruments. Thus, the opening of these seals is small in diameter relative to the largest diameter instrument.

In fact, it is not uncommon to push the lip seal to a strain of 400%. By forcing these larger diameter instruments through the relatively smaller diameter lip seals, these larger diameter instruments experience a significant increase in the normal force acting on the instrument shaft. These increased forces can cause the surgeon to experience increased drag or pull on the insertion/movement of the instrument. There is also a need for the material properties of the seal to be such that it does not crack or tear when it is stretched to its limit. Accordingly, there is a need for an improved trocar seal assembly that overcomes the deficiencies of the prior art.

Disclosure of Invention

The present invention overcomes these deficiencies by providing a seal assembly that eliminates the hoop stress/high stress problems associated with prior art seal assemblies and provides a seal assembly that can be used both as a stand-alone sealing method (reducing the overall complexity of the trocar) and as a proximal seal assembly for a multiple seal system.

Accordingly, it is an object of the present invention to provide a seal assembly adapted for use in conjunction with a trocar assembly. The seal assembly includes a plurality of sealing sheets. Each sealing panel has a peripheral edge and a seaming edge. At least a first seal piece and a second seal piece are connected along their respective peripheral edges to form a first seal layer having a seam defined by a seam edge of the first seal piece and a seam edge of the second seal piece. At least a third seal segment and a fourth seal segment are connected along their respective peripheral edges to form a second seal layer having a seam defined by a seam edge of the third seal segment and a seam edge of the fourth seal segment. The seam of the first seal layer has a first longitudinal axis and the seam of the second seal layer has a second longitudinal axis, and the first seal layer is oriented relative to the second seal layer in a manner such that the first longitudinal axis is oriented at an included angle relative to the second longitudinal axis.

It is another object of the present invention to provide a trocar assembly including a trocar cannula having a proximal end and a distal end, the trocar assembly further including a trocar housing coupled to the proximal end of the trocar cannula for receiving and guiding an obturator therethrough. The trocar housing includes an open proximal end portion defining an opening for the seal assembly. The seal assembly is constructed as follows.

(1) The present invention relates to a seal assembly adapted for use in conjunction with a trocar assembly, the seal assembly comprising: a plurality of sealing panels, each sealing panel including an arcuate peripheral edge and a seam edge, each sealing panel further including an extended corner portion having a shape and size capable of joining with an adjacent sealing panel, wherein the corner portion is tapered to facilitate joining with an adjacent sealing panel; at least a first seal piece and a second seal piece are joined together along their respective peripheral edges to form a first seal layer having a seam defined by a seam edge of the first seal piece and a seam edge of the second seal piece; at least a third seal segment and a fourth seal segment joined together along their respective peripheral edges to form a second seal layer having a seam defined by a seam edge of the third seal segment and a seam edge of the fourth seal segment; wherein the seam of the first seal layer has a first longitudinal axis and the seam of the second seal layer has a second longitudinal axis, and the first seal layer is oriented relative to the second seal layer such that the first longitudinal axis is angularly oriented relative to the second longitudinal axis.

(2) The seal assembly of item (1), wherein the first longitudinal axis is oriented at about 90 degrees relative to the second longitudinal axis.

(3) The seal assembly of item (1), wherein the seam edge of each sealing panel is straight.

(4) The seal assembly according to item (1), wherein the seam edge of each sealing panel is S-shaped.

(5) The seal assembly of item (1), wherein the corner portion of each sealing sheet is tapered on one side as it extends towards the tip of the corner portion and a matching taper is formed along the underside of each sealing sheet to facilitate coupling of adjacent sealing sheets during formation of the sealing layer.

(6) The seal assembly of item (1), wherein the first sealant layer and the second sealant layer are substantially flat.

(7) The seal assembly of item (1), wherein the peripheral edge of each sealing disc defines an arc of 200 and 220 degrees.

(8) The seal assembly of item (1), wherein the first and second seal layers are substantially conical in shape.

(9) The seal assembly according to item (1), wherein each sealing plate is an elastomer of a cross-linked polymer.

(10) The present invention also relates to a trocar assembly comprising: a trocar cannula including a proximal end and a distal end; and a trocar housing coupled to the proximal end of the trocar cannula for receiving and guiding the obturator therethrough, the trocar housing having an open proximal portion defining an opening for the sealing assembly; the seal assembly includes: a plurality of sealing panels, each sealing panel including a peripheral edge and a seaming edge; at least a first seal piece and a second seal piece are joined together along their respective peripheral edges to form a first seal layer having a seam defined by a seam edge of the first seal piece and a seam edge of the second seal piece; at least a third seal segment and a fourth seal segment joined together along their respective peripheral edges to form a second seal layer having a seam defined by a seam edge of the third seal segment and a seam edge of the fourth seal segment; wherein the seam of the first seal layer has a first longitudinal axis, the seam of the second seal layer has a second longitudinal axis, and the first seal layer is oriented relative to the second seal layer in a manner such that the first longitudinal axis is oriented at an angle relative to the second longitudinal axis.

(11) The trocar assembly of claim (10) wherein the first longitudinal axis is oriented at about 90 degrees relative to the second longitudinal axis.

(12) The trocar assembly of claim (10) wherein the seam edge of each sealing flap is straight.

(13) The trocar assembly of claim (10) wherein the seam edge of each sealing flap is S-shaped.

(14) The trocar assembly of claim 10 wherein each sealing flap includes an extended angular portion shaped and sized to be attachable to the respective sealing flap.

(15) The trocar assembly of claim (14) wherein the angled portion of each sealing flap is tapered to facilitate connection of adjacent sealing flaps during formation of the sealing layer.

(16) The trocar assembly of claim (10) wherein the first and second sealing layers are substantially flat.

(17) The trocar assembly of claim 10 wherein the peripheral edge of each sealing flap is substantially semicircular.

(18) The trocar assembly of claim (10) wherein the first and second sealing layers are substantially conical.

(19) The trocar assembly of claim 10 wherein each sealing disc is an elastomer of a cross-linked polymer.

Other objects and advantages of this invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings which illustrate some embodiments of this invention.

Drawings

Fig. 1 is an exploded view of a trocar assembly according to the present invention.

Fig. 2 is an exploded view of a trocar assembly according to the embodiment disclosed in fig. 3, 4 and 5.

Figure 3 is an exploded perspective view of the first and second sealing sheets according to the present invention.

Fig. 4 is a perspective view of a sealing layer composed of the first and second sealing sheets shown in fig. 3.

Fig. 5 is a cross-sectional view of the sealing layer according to fig. 4.

Figure 6 is an exploded perspective view of another embodiment of the first and second sealing sheets.

Fig. 7 is a perspective view of a sealing layer composed of the first and second sealing sheets shown in fig. 6.

Fig. 8 is a cross-sectional view of the sealing layer according to fig. 7.

Fig. 9 is an exploded perspective view of an alternative embodiment of a sealing layer comprised of first and second sealing sheets according to another embodiment.

Figure 10 is an exploded perspective view of the first and second sealing sheets according to figure 9.

FIG. 11 is a cross-sectional view of the sealant layer taken along line 11-11 of FIG. 9.

FIG. 12 is a perspective view of a sealing layer according to another embodiment.

Figure 13 is an exploded perspective view of the first and second sealing sheets according to figure 12.

FIG. 14 is a cross-sectional view of the sealing layer taken along line 14-14 of FIG. 12.

FIG. 15 is a perspective view of a sealing layer according to yet another embodiment.

Figure 16 is an exploded perspective view of the first and second sealing sheets according to figure 15.

FIG. 17 is a cross-sectional view of the sealant layer taken along line 17-17 of FIG. 15.

Detailed description of the preferred embodiments

Detailed embodiments of the present invention are described herein. However, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention.

Referring to fig. 1, 2, 3, 4 and 5, a seal assembly 10 for a trocar assembly 12 is disclosed. By reducing the likelihood of tenting occurring, the seal assembly 10 provides improved tear resistance. As will be appreciated by those skilled in the art, bulging occurs when the seal is stretched and thinned, such as by an instrument, through the seal, thereby providing a weakened area that is easily punctured. The seal assembly 10 of the present invention is adapted for use with a variety of trocar assemblies 12, as will be appreciated by those skilled in the art.

The conventional construction of the trocar assembly 12 forms no part of the present invention other than the seal assembly 10 according to the present invention. For example and by way of explanation of the seal assembly 10 of the present invention, trocar assembly 12 may take a variety of forms without departing from the spirit of the present invention.

With this in mind, by way of example, the trocar assembly 12 includes a trocar cannula 14, a trocar obturator 16, and a trocar housing 18. The trocar cannula 14 defines a lumen having an open distal portion and an open proximal portion. The proximal end portion extends into and is secured within the distal end portion of the trocar housing 18. The trocar housing 18 has an open proximal end portion that defines an opening 20. The opening 20 is equipped with a proximal seal assembly 10 constructed in accordance with the present invention as will be described in detail below. The opening 20 is also equipped with a duckbill seal assembly 22 positioned below the proximal seal assembly 10. Although the present seal assembly 10 is disclosed as a proximal seal assembly 10 forming part of a dual seal system, the present seal assembly may also be used in a single seal system without departing from the spirit of the present invention.

The trocar obturator 16 slidably and movably extends within the trocar cannula 14 and is inserted into the trocar housing 18 and trocar cannula 14 through the proximal seal assembly 10, the duckbill seal assembly 22 and the opening 20 of the trocar housing 18. An obturator handle 24 is provided at the proximal end of the trocar obturator 16 and defines a sharp point or blade (not shown) at its distal end. As is well known in the art, the seal assembly 10 cooperates with a trocar obturator 16 or another surgical instrument extending through the trocar cannula 14 to sealingly engage the outer surface of the trocar cannula, thereby preventing fluid from flowing therethrough via the trocar housing 18.

With reference to various embodiments according to the present invention, the proximal seal assembly 10 is assembled from a plurality of overlapping sealing sheets 26a, 26b, 26a ', 26 b', thereby minimizing leakage between the seal assembly 10 and the shaft, shaft or collar of various instruments inserted. Specifically, four seal plates 26a, 26b, 26a ', 26 b' are arranged to form a seal body 28 of the seal assembly 10. Although four sealing sheets are employed according to the preferred embodiment of the present invention, the seal assembly may ultimately be made with a different number of sealing sheets without departing from the spirit and scope of the present invention.

Referring to fig. 2, a preferred embodiment of the present seal assembly 10 is disclosed. The seal assembly 10 employs several radially oriented sealing sheets 26a, 26b, 26a ', 26 b' which fold about the shaft of the inserted instrument. According to the proposed embodiment, the circumferential stress is reduced by replacing the single hole in the prior art lip seal with a plurality of annularly positioned sealing sheets 26a, 26b, 26a ', 26 b'. These sealing sheets 26a, 26b, 26a ', 26 b' provide a seal similar to that provided by the circular holes of prior art lip seals when opened with a circular probe. While the resulting design is both easy to shape and easy to inspect, it also employs beveled edge features for wrapping the instrument shaft.

As will be discussed in more detail below, the seal assembly 10 of the present invention employs a series of interlocking sealing sheets 26a, 26b, 26a ', 26 b'. The preferred embodiment disclosed herein employs four sealing sheets 26a, 26b, 26a ', 26 b', although the use of more than four sealing sheets does not depart from the spirit of the present invention. All four sealing sheets 26a, 26b, 26a ', 26 b' are individually formed and then assembled to form the final configuration.

By providing a single seal assembly 10 having multiple layers, i.e. having sealing sheets 26a, 26b, 26a ', 26 b' overlapping each other in a manner to form a through hole, the circumferential stress of the seal assembly 10 of the present invention is reduced. These layers form the area of contact with the inserted probe. The sum of the contact areas provides contact around the entire diameter of the insertion instrument. Without probe insertion, the sealing sheets 26a, 26b, 26a ', 26 b' remain in contact with each other, leaving no air passage for the seal assembly 10.

The proximal seal assembly 10 is constituted by a seal body 28, the seal body 28 being constituted by two seal layers 34, 34 ' constituted by a pair of seal sheets 26a, 26b, 26a ', 26b ', respectively. Once the two seal layers 34, 34 'are properly constructed, the second seal layer 34' is placed under the first seal layer 34 and the seal seam 36 'of the second seal layer 34' is rotated 90 ° from the seal seam 36 of the first seal layer 34. In this manner, the seal seams 36, 36 'of the first and second seal layers 34, 34' form a double seam seal, thereby providing an improved annular seal in the trocar housing 18.

The holes 37, 37 ' are formed along the peripheral edges 35a, 35b, 35a ', 35b ' of the respective sealing sheets 26a, 26b, 26a ', 26b ' and are spaced apart so as to enable the holes 37, 37 ' to be aligned when the sealing layers 34, 34 ' are properly aligned and rotated 90 degrees. In this manner, the male (male) and female (female) clamping rings 44, 46 are positioned on opposite sides of the juxtaposed first and second sealant layers 34, 34'. The male clamping ring 44 includes a series of connection prongs (prong)45 that extend through the holes 37, 37 'of the seal layers 34, 34' and connect with notches 47 formed in the female sealing ring 46. In this manner, the seal body 28, which is comprised of the first and second seal layers 34, 34', is securely positioned between the male and female retainer rings 44, 46 and ultimately supported for connection of the trocar housing 18.

Fig. 2 illustrates an embodiment wherein the sealing assembly 10 is provided with sealing layers 34, 34 ' comprising sealing sheets 26a, 26b, 26a ', 26b '. According to this embodiment, no central hole is left for the sealing discs 26a, 26b, 26a ', 26 b'. It is believed that this arrangement provides the best seal before and after insertion of the rod. However, according to an alternative embodiment, an optional clearance opening 127(clearance opening) may also be utilized, as shown in fig. 6, 7 and 8.

In practice, when a device such as a rod or shaft is inserted through the seal assembly 100, the overlapping pieces of the first and second seal layers 34, 34' are both deflected downward and surround the inserted device. This deflection creates a cat-eye effect (cat-eye effect) on the first sealing layer 34, leaving a gap between the insert means and the first and second sealing sheets 26a, 26b constituting the first sealing layer 34. Since the seam 36 ' of the second seal layer 34 ' is rotated 90 degrees from the seam 36 of the first seal layer 34, the second seal layer 34 ' makes up for the gap between the inserted device and the sealing sheets 26a, 26b of the first seal layer 34, forming an annular seal around the inserted device.

Various embodiments of the present invention have been devised as will be described more fully below. Various embodiments describe various applications of the inventive concept including planar sealing panels with straight seam edges, planar sealing panels with S-shaped seam edges, tapered sealing panels with straight sealing seams, and tapered sealing panels with S-shaped seam edges.

While the seal assembly 10 of the present invention is particularly suited for use with a trocar assembly, it will be understood by those skilled in the art that the seal assembly of the present invention may also be used for different functions without departing from the spirit of the present invention.

Referring to fig. 3, 4 and 5, a preferred embodiment of the sealing layer 34 is disclosed. Which is the same as the sealing layer 34 disclosed with reference to fig. 2. Each sealing flap 26a, 26b according to the present embodiment is semicircular and planar with a straight seam edge 38a, 38 b. As shown in fig. 3, and as described in detail below, the use of the direct seam edges 38a, 38b creates a sealed seam 36 formed along a substantially straight line.

Referring to fig. 3, 4 and 5, each of these planar sealing sheets 26a, 26b comprises a substantially flat semicircular disc having a substantially circular peripheral edge 35a, 35b and a straight seam edge 38a, 38b defining a straight sealing seam 36. In accordance with the preferred embodiment of the present invention, the peripheral edge 35a, 35b of each sealing flap 26a, 26b defines an arc of approximately 200 and 220 degrees. The peripheral edges 35a, 35b also include a series of holes 37 that serve as a means of attaching the sealing sheets 26a, 26 b. The sealing sheets 26a, 26b also include respective radially extending tapered angled portions 30a, 30b (tapered angled sections) for connecting adjacent sealing sheets 26a, 26b, respectively. The angled portions 30a, 30b are each tapered on one side. A matching taper 32a, 32b is also formed along the underside of each seal 26a, 26b opposite the angled portion 30a, 30 b. The angled portions 36a, 36b of the sealing sheets 26a, 26b provide increased contact between the assembled sealing sheets.

As described above, the radially extending angular portions 30a, 30b are tapered (tapered) as they extend toward their distal ends. The underside of each sealing flap 26a, 26b opposite the angled portion 30a, 30b is similarly formed with a taper 32a, 32b that matches the taper of the angled portion 30a, 30 b. In this manner, the angled portion 30a of the first seal fin 26a is disposed in the matching taper 32b along the underside of the second seal fin 26b, and the angled portion 30b of the second seal fin 26b is disposed in the matching taper 32b along the underside of the first seal fin 26 a. The mating tapers 32a, 32b allow for the formation of a first seal layer 34 without unwanted ridges or flanges along its underside due to the coupling of the first seal piece 26a and the second seal piece 26 b.

In practice, and referring to fig. 3, 4 and 5, two sealing sheets 26a, 26b are joined in overlying relationship to form a first sealant layer 34. Thus, the first seal layer 34 is formed to define a complete circular perimeter with a straight seal seam 36 extending between the first seal flap 26a and the second seal flap 26 b. As will be described in detail below, the shape of the seam edges 38a, 38b of the sealing panels 26a, 26b ultimately defines the shape of the sealing seam 36 extending between the first and second sealing panels 26a, 26b that make up the first sealing layer 34.

As previously mentioned, the inventive concept can be implemented by employing various seal layer structures without departing from the spirit of the invention. Some of these concepts are disclosed below. As it is believed that those skilled in the art will understand the manner in which the seal layers are assembled in the same manner as described above with reference to fig. 2, the details of construction of the overall seal assembly are not repeated herein, and the following disclosure focuses on the construction of a single seal layer.

Referring to fig. 6, 7 and 8, another embodiment according to the present invention is disclosed. This embodiment is substantially similar to the embodiment disclosed with reference to fig. 3, 4 and 5, but includes a central void opening 127. Each sealing flap 126a, 126b according to the present embodiment is semi-circular and planar with straight seam edges 138a, 138 b. As shown in fig. 7, and as described in detail below, the use of straight seam edges 138a, 138b creates a sealed seam 136 that is formed along a substantially straight line.

Referring to fig. 6, 7 and 8, each of these planar sealing sheets 126a, 126b comprises a substantially flat semicircular disc having a substantially circular peripheral edge 135a, 135b and a straight seam edge 138a, 138b defining a straight sealing seam 136. Each sealing flap 126a, 126b also includes a central void recess 127a, 127b that ultimately defines a central void opening 127.

In accordance with a preferred embodiment of the present invention, the peripheral edge 135a, 135b of each sealing disc 126a, 126b defines an arc of approximately 200 and 220 degrees. The peripheral edges 135a, 135b also include a series of holes 137 that serve as a means for attaching the sealing sheets 126a, 126 b. The sealing sheets 126a, 126b also include radially extending tapered horns 130a, 130b, respectively, that connect adjacent sealing sheets 126a, 126b in the same manner as described above. The angled portions 130a, 130b are tapered on one side, respectively. A matching taper 132a, 132b is also formed along the underside of each sealing disc 126a, 126b opposite the angled portion 130a, 130 b. The angled portions 130a, 130b of the sealing sheets 126a, 126b provide increased contact between the assembled sealing sheets 126a, 126 b.

In practice, and referring to fig. 6, 7 and 8, two sealing sheets 126a, 126b are joined in a stacked relationship to form a first sealant layer 134. Thus, the first seal layer 134 is formed to define a complete circular perimeter with a straight seal seam 136 extending between the first seal piece 126a and the second seal piece 126 b. As will be described in detail below, the shape of the seam edges 138a, 138b of the sealing panels 126a, 126b ultimately defines the shape of the sealing seam 136 extending between the first and second sealing panels 126a, 126b that comprise the first sealing layer 134.

Another embodiment is disclosed with reference to fig. 9, 10 and 11 and relates to a sealing layer 234 formed of planar sealing sheets 226a, 226b having S-shaped seam edges 238a, 238 b. As shown in FIG. 10, and as described in more detail below, the use of S-shaped seam edges 238a, 238b creates a substantially S-shaped sealing seam 236. Each planar sealing piece 226a, 226b comprises a substantially flat semi-circular disc having a substantially circular peripheral edge 235a, 235b and an S-shaped edge that ultimately defines a seam edge 238a, 238 b. Finally, a seal employing two such sealing layers 224 as described above forms a seal assembly having an S-cut sealed seam 236.

In accordance with a preferred embodiment of the present invention, the peripheral edges 235a, 235b of each sealing flap 226a, 226b define an arc of approximately 200 and 220 degrees. The peripheral edges 235a, 235b also include a series of holes 237 that serve as a means for attaching the sealing panels 226a, 226 b. The sealing sheets 226a, 226b also include radially extending tapered horns 230a, 230b, respectively, that connect adjacent sealing sheets 226a, 226b in the same manner as described above. A matching taper 232a, 232b is also formed along the underside of each sealing flap 226a, 226b opposite the angled portion 230a, 230 b. The angled portions 230a, 230b of the sealing sheets 226a, 226b provide increased contact between the assembled sealing sheets 226a, 226 b.

In practice, and referring to the drawings, two sealing sheets 226a, 226b are joined in overlying relationship to form a first sealant layer 234. Thus, the first sealing layer 234 is formed to define a complete circular perimeter, and an S-shaped sealing seam 236 extends between the first sealing flap 226a and the second sealing flap 226 b. As will be described in detail below, the S-shape of the seam edges 238a, 238b of each sealing panel 226a, 226b ultimately defines the shape of the sealing seam 236 extending between the first and second sealing panels 226a, 226b that form the first sealing layer 234.

A further embodiment is disclosed with reference to fig. 12, 13 and 14. This embodiment relates to a sealing layer 334 consisting of conical sealing sheets 326a, 326b with straight seam edges 338a, 338 b. As shown in the figures, and as described in more detail below, the use of the direct seam edges 338a, 338b creates a substantially straight sealed seam 336. Each conical sealing flap 326a, 326b comprises a conical structure extending only around a part of the circle. Thus, the conical sealing fins 326a, 326b can be considered to form a "half cone". Each of the half cones includes a flat, substantially circular outer peripheral edge 335a, 335b and a straight seam edge 338a, 338 b.

In accordance with a preferred embodiment of the present invention, the peripheral edge 335a, 335b of each sealing flap 326a, 326b defines an arc of approximately 200 and 220 degrees. The peripheral edges 335a, 335b also include a series of holes 337 that serve as a means for attaching the sealing panels 326a, 326 b. The sealing tabs 326a, 326b also include radially extending tapered horns 330a, 330b, respectively, that are attached adjacent sealing tabs 326a, 326b in the same manner as described above. A matching taper 332a, 332b is also formed along the underside of each sealing flap 326a, 326b opposite the angled portion 330a, 330 b. The angled portions 330a, 330b of the sealing sheets 326a, 326b provide increased contact between the assembled sealing sheets 326a, 326 b.

In practice, and referring to the figures, two sealing sheets 326a, 326b are joined in a stacked relationship to form a first sealant layer 334. Thus, the first seal layer 334 is formed to define a complete cone, and a straight seal seam 336 extends between the first seal flap 326a and the second seal flap 326 b. As described below, the shape of the seam edges 338a, 338b of the sealing panels 326a, 326b ultimately defines the shape of the sealing seam 336 extending between the first and second sealing panels 326a, 326b that comprise the first sealing layer 334.

A further embodiment is disclosed with reference to fig. 15, 16 and 17, which relates to a sealing layer 434 consisting of conical sealing sheets 426a, 426b with S-shaped seam edges 438a, 438 b. The conical nature of this embodiment reduces the likelihood of seal eversion when the instrument is withdrawn and provides a natural "lead" toward the conical seal assembly.

As shown in fig. 15, 16 and 17, and as described in more detail below, a further embodiment of a sealing layer 434 formed by sealing sheets 426a, 426b is disclosed. The use of the S-shaped seam edges 438a, 438b creates a substantially S-shaped sealing seam 436. Referring to the figures, each conical sealing piece 426a, 426b comprises a conical structure that extends around only a portion of a circle. Thus, the conical seal piece can be considered to constitute a "half cone". Each of the half cones includes a flat, substantially circular outer peripheral edge 435a, 435b and an S-shaped edge defining a seaming edge 438a, 438 b.

In accordance with a preferred embodiment of the present invention, the peripheral edge 435a, 435b of each sealing flap 426a, 426b defines an arc of approximately 200 and 220 degrees. The peripheral edges 435a, 435b also include a series of holes 437 that serve as a means for attaching the sealing panels 426a, 426 b. The sealing sheets 426a, 426b also include radially extending tapered horns 430a, 430b, respectively, that connect adjacent sealing sheets 426a, 426b in the same manner as described above. A matching taper 432a, 432b is also formed along the underside of each sealing flap 426a, 426b opposite the angled portion 430a, 430 b. The angled portions 430a, 430b of the sealing blades 426a, 426b provide increased contact between the assembled sealing blades 426a, 426 b.

In practice, two sealing panels 426a, 426b are joined in a superposed relationship along their respective peripheral edges 435a, 435b to form a first sealing layer 434. The first seal layer 434 so formed defines a complete cone, and a seal seam 436 extends between the first seal panel 426a and the second seal panel 426 b. As described below, the shape of the seam edges 438a, 438b of each sealing panel 426a, 426b ultimately defines the shape of the sealing seam 436 extending between the first and second sealing panels 426a, 426b that make up the first sealing layer 434.

The conical nature of the seal assembly reduces the likelihood of seal eversion upon withdrawal of the instrument. The seal upset can lead to binding of the instrument when it is removed from the trocar, which can be cumbersome during withdrawal. The conical feature also provides a natural guide toward the center of the seal assembly. This guides the insertion of the instrument toward the center of the seal assembly and reduces the likelihood of puncture through the seal at a location toward the conical periphery.

According to a preferred embodiment of the invention, the sealing disc is made of an elastomer or a cross-linked polymer, such as, but not limited to, silicone or polyisoprene. However, those skilled in the art will appreciate that other materials may be employed without departing from the spirit of the present invention.

While the preferred embodiment has been illustrated and described, it is to be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all structural modifications and variations falling within the spirit and scope of the invention, as defined in the appended claims.

Claims (9)

1. A seal assembly adapted for use in conjunction with a trocar assembly, the seal assembly comprising:

a plurality of sealing panels, each sealing panel including an arcuate peripheral edge and a seam edge, each sealing panel further including an extended corner portion having a shape and size capable of joining with an adjacent sealing panel, wherein the corner portion is tapered to facilitate joining with an adjacent sealing panel;

at least a first seal piece and a second seal piece are joined together along their respective peripheral edges to form a first seal layer having a seam defined by a seam edge of the first seal piece and a seam edge of the second seal piece;

at least a third seal segment and a fourth seal segment joined together along their respective peripheral edges to form a second seal layer having a seam defined by a seam edge of the third seal segment and a seam edge of the fourth seal segment;

wherein the seam of the first seal layer has a first longitudinal axis and the seam of the second seal layer has a second longitudinal axis, and the first seal layer is oriented relative to the second seal layer such that the first longitudinal axis is angularly oriented relative to the second longitudinal axis.

2. The seal assembly of claim 1, wherein the first longitudinal axis is oriented 90 degrees relative to the second longitudinal axis.

3. The seal assembly of claim 1, wherein the seam edge of each sealing flap is straight.

4. The seal assembly of claim 1, wherein the seam edge of each sealing flap is S-shaped.

5. The seal assembly of claim 1, wherein the horn of each sealing segment is tapered on one side as it extends toward the tip of the horn and a matching taper is formed along the underside of each sealing segment to facilitate coupling of adjacent sealing segments during formation of the seal layer.

6. The seal assembly of claim 1, wherein the first sealant layer and the second sealant layer are flat.

7. The seal assembly of claim 1, wherein the peripheral edge of each sealing disc defines an arc of 200 and 220 degrees.

8. The seal assembly of claim 1, wherein the first seal layer and the second seal layer are conical in shape.

9. The seal assembly of claim 1, wherein each sealing disc is an elastomer composed of a cross-linked polymer.