Molded insulating hinge for bipolar instruments

• US 20040193153A1
• Filed: 09/29/2003
• Published: 09/30/2004
• Est. Priority Date: 04/06/2001
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: Harvilla, Dennis J., Sartor, Joe Don
• Granted Patent: US 7,103,947 B2
• Time in Patent Office: Days
• US Class Current: 606/48
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
• CPC Class Codes: A61B 2017/2939 Details of linkages or pivot points
• CPC Class Codes: A61B 2018/126 bipolar
• CPC Class Codes: Y10T 29/24 Hinge making or assembling
• CPC Class Codes: Y10T 29/49888 Subsequently coating
• CPC Class Codes: Y10T 29/4998 Combined manufacture including applying or shaping of fluent material

Abstract

An electrosurgical instrument includes a pair of first and second elongated shafts each having an end effector attached to a distal end thereof and a handle. The handle is movable from a first position wherein the end effectors are disposed in spaced relation relative to one another to a second position wherein the end effectors are closer relative to one another. Each of the elongated shafts includes a hinge plate which mounts atop a pivot assembly for effecting movement of the end effectors relative to one another. The instrument also includes a hinge assembly made from an overmold composition which encapsulates and secures the hinge plates and the pivot assembly. The overmold composition is made from an electrically insulating material which insulates the end effectors from one another.

Claims

1. An electrosurgical instrument comprising:

of first and second elongated shafts each having an end effector attached to a distal end thereof and a handle, said handle being movable from a first position wherein the end effectors are disposed in spaced relation relative to one another to a second position wherein the end effectors are closer relative to one another;

each of said elongated shafts including a hinge plate which mounts atop a pivot assembly which effects movement of the end effectors relative to one another; and

a hinge assembly made from an overmold composition which, when cured, encapsulates said hinge plates, said overmold composition of said hinge assembly being made from an electrically insulating material which insulates each of said end effectors from one another.

2. An electrosurgical instrument according to claim 1 wherein said pivot assembly includes a pivot pin integrally associated with a first of said hinge plates and a pivot hole formed within a second of said hinge plates, said pivot pin being made from an electrically insulating material.

3. An electrosurgical instrument according to claim 1 wherein said pivot assembly includes a pivot pin integrally associated with a first of said hinge plates and a pivot hole formed within a second of said hinge plates, said overmold composition of said hinge assembly when cured being disposed between said pivot pin and said pivot hole to electrically insulate each of said hinge plates from one another.

4. An electrosurgical instrument according to claim 1 wherein said overmold composition of said hinge assembly includes materials selected from the group consisting of polyamides, nylon, arcylanitride-butane nitro styrene acetyl, polyesters, syndiotactic-polystryrene (SPS), polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyphthalamide (PPA), polymide, polyethylene perephthalate (PET), polyamide-imide (PAI), acrylic (PMMA), polystyrene (PS and HIPS), polyether sulfone (PES), aliphatic polyketone, acetal (POM) copolymer, polyurethane (PU and TPU), nylon with polyphenylene-oxide dispersion and acrylonitrile styrene acrylate.

5. An electrosurgical instrument according to claim 4 wherein said overmold composition of said hinge assembly includes lubricating materials selected from the group consisting of silicon, molybdenum disulfide and light olefins.

6. An electrosurgical instrument according to claim 1 wherein said hinge assembly includes a retention tab which secures said hinge assembly between said hinge plates.

7. An electrosurgical instrument according to claim 4 wherein said pivot assembly includes a pivot pin integrally associated with a first of said hinge plates and a pivot hole formed within a second of said hinge plates, said pivot pin including a reinforcing portion disposed therein which permits said overmold composition of said hinge assembly to extrude through said pivot pin to form a retention tab for securing said hinge assembly between said hinge plates.

8. An electrosurgical instrument according to claim 1 wherein said hinge assembly includes a stop member for limiting the movement of said end effectors relative to one another.

9. A method of forming a hinge assembly comprising the steps of:

providing a pair of first and second elongated shafts each having an end effector attached to a distal end thereof, a handle and a hinge plate, said handle effecting movement of the end effectors relative to one another;

mounting said elongated shafts to a die block;

introducing an overmold composition into said die block to encapsulate at least a portion of said hinge plates; and

curing said overmold composition to form said hinge assembly.

10. A method according to claim 9 wherein prior to said curing step, the method further includes the step of:

selectively positioning at least one spacer between said end effectors to maintain a gap distance between said end effectors during the curing step.

11. A method according to claim 9 wherein said overmold composition of said introducing step includes materials selected from the group consisting of polyamides, nylon, arcylanitride-butane nitro styrene acetyl, polyesters, syndiotactic-polystryrene (SPS), polybutylene terephthalate (PBT), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyphthalamide (PPA), polymide, polyethylene perephthalate (PET), polyamide-imide (PAI), acrylic (PMMA), polystyrene (PS and HIPS), polyether sulfone (PES), aliphatic polyketone, acetal (POM) copolymer, polyurethane (PU and TPU), nylon with polyphenylene-oxide dispersion and acrylonitrile styrene acrylate.

12. A method according to claim 9 wherein said overmold composition of said introducing step includes lubricating materials selected from the group consisting of silicon, molybdenum disulfide and light olefins.