Method and Apparatus for Creating Formed Elements Used to Make Wound Stents
A method for forming a wave form for a stent includes providing a length of a formable material from a supply of the formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member. The second forming member is positioned closer to the feeder than the first forming member. The length is about the length of a substantially straight portion of the wave form. The method also includes moving the first forming member in a second direction substantially perpendicular to the first direction to a position in contact with the formable material, and moving the second forming member in a third direction substantially opposite the second direction to wrap the formable material about a distal end of the first forming member.
Latest Medtronic Vascular, Inc. Patents:
This application claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 61/243,578, filed on Sep. 18, 2009, the entire content of which is incorporated herein by reference. This application also claims the benefit of priority from U.S. Provisional Patent Application Ser. Nos. 61/243,581, 61/243,582, 61/243,592, 61/243,597, and 61/243,600, all filed on Sep. 18, 2009, the entire contents of all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention is generally related to an apparatus and method for forming a wave form for a stent. More particularly, the present invention is related to an apparatus and method for forming the wave form from a formable material, such as a wire or a strip of material.
2. Background of the Invention
A stent is typically a hollow, generally cylindrical device that is deployed in a body lumen from a radially contracted configuration into a radially expanded configuration, which allows it to contact and support a vessel wall. A plastically deformable stent can be implanted during an angioplasty procedure by using a balloon catheter bearing a compressed or “crimped” stent, which has been loaded onto the balloon. The stent radially expands as the balloon is inflated, forcing the stent into contact with the body lumen, thereby forming a support for the vessel wall. Deployment is effected after the stent has been introduced percutaneously, transported transluminally, and positioned at a desired location by means of the balloon catheter.
Stents may be formed from wire(s) or strip(s) of material, may be cut from a tube, or may be cut from a sheet of material and then rolled into a tube-like structure. While some stents may include a plurality of connected rings that are substantially parallel to each other and are oriented substantially perpendicular to a longitudinal axis of the stent, others may include a helical coil that is wrapped or wound around a mandrel aligned with the longitudinal axis at a non-perpendicular angle.
Stent designs that are comprised of wound materials generally have complex geometries so that the final stents may be precisely formed. The small size and complexity of some stent designs generally makes its formation difficult. Wound stents are formed such that when unsupported, they create the desired stent pattern and vessel support. This process generally involves winding a source material around a supporting structure such as a rod or mandrel and creating a helical or spring-like wrap pattern. To provide greater support, along this wrapped element, geometries are formed into the source material to better support the tissue in between each wrap, usually of sinusoidal nature. A potential down side to a wrapped stent is that the ends of the stent are generally not perpendicular to the longitudinal axis of the stent, but rather terminate at a pitch angle induced by the helical wrapping.
SUMMARY OF THE INVENTIONEmbodiments of the present invention describe an apparatus and method for forming a wave form for a stent that provides formed geometries that can alter a pitch angle such that the wound stent terminates at a substantially perpendicular angle to the longitudinal axis of the stent. More specifically, the apparatus and method according to embodiments of the present invention allow for the amplitude and wavelength of any individual or half element of the wave form to be manipulated to provide the desired interwrap support.
According to an aspect of the present invention, there is provided a method for forming a wave form for a stent. The method includes providing a length of a formable material from a supply of formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member. The second forming member is positioned closer to the feeder than the first forming member. The method also includes moving a distal end of the first forming member across the axis in a second direction substantially perpendicular to the first direction to engage and deform the formable material while engaging the formable material with a distal end of the second forming member, moving the distal ends of the first and second forming members across the axis in a third direction that is substantially opposite the second direction to draw and form the formable material over the distal end of the second forming member, and disengaging the first forming member from the forming material. The method also includes moving the first forming member and the second forming member relative to each other so that the first forming member is positioned closer to the feeder than the second forming member, moving the distal end of the first forming member into engagement with the deformable material, and moving the distal ends of the first and second forming members across the axis in the second direction to draw and form the formable material over the distal end of the first forming member.
According to an aspect of the present invention, there is provided a method for forming a wave form for a stent. The method includes providing a length of a formable material from a supply of formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member. The second forming member is positioned closer to the feeder than the first forming member. The length is about the length of a substantially straight portion of the wave form. The method also includes moving the first forming member in a second direction substantially perpendicular to the first direction to a position in contact with the formable material, and moving the second forming member in a third direction substantially opposite the second direction to wrap the formable material about a distal end of the first forming member.
According to an aspect of the present invention, there is provided a method for forming a wave form for a stent that includes providing a length of a formable material from a supply of formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member. The second forming member is positioned closer to the feeder than the first forming member. The method includes moving the first forming member into contact with the formable material and across the axis in a second direction substantially perpendicular to the first direction, and folding the formable material over the second forming member by moving the second forming member and the first forming member in a third direction substantially opposite the second direction and moving the second forming member and the first forming member in a fourth direction substantially opposite the first direction.
According to an aspect of the present invention, there is provided a forming apparatus configured to form a wave form for a stent out of a formable material. The wave form includes a plurality of substantially straight portions and a plurality of curved portions. The apparatus includes a feeder constructed and arranged to receive a supply of the formable material and provide the formable material along an axis, and a first forming member configured to be movable along two orthogonal axes. The first forming member includes a first elongated portion having a first engaging surface at a distal end of the first elongated portion. The first engaging surface is configured to engage a first side of the formable material. The apparatus also includes a second forming member configured to be movable along the two orthogonal axes. The second forming member includes a second elongated portion having a second engaging surface at a distal end of the second elongated portion. The second engaging surface is configured to engage a second side of the formable material that is opposite the first side. The apparatus also includes a controller in communication with the feeder, the first forming member, and the second forming member. The controller is configured to control movement of the first and second forming members to control a length of each substantially straight portion of the wave form and to control a wavelength within the wave form.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and use of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
The forming apparatus 10 also includes a first forming member 20 and a second forming member 30. The first forming member 20 includes an elongated, or finger-like, portion 22 that has an engaging surface 24 at a distal end thereof. The engaging surface 24 is configured to engage the formable material 12 on one side thereof and deform the formable material 12 into a desired shape, as discussed in further detail below.
Similar to the first forming member 20, the second forming member 30 includes an elongated, or finger-like, portion 32 that has an engaging surface 34 at a distal end thereof. The engaging surface 34 is configured to engage the formable material 12 on a side that is opposite the side of the formable material 12 that is engaged by the engaging surface 24 of the first forming member 20. As illustrated in
The first forming member 20 and the second forming member 30 may be moved relative to the feeder 14 by actuators 26, 36, respectively, that are schematically illustrated in
In operation, the first forming member 20 is initially positioned on one side of the axis AX, and the second forming member 30 is initially positioned on the opposite side of the axis AX relative to the first forming member 20 such that the engaging surface 24 of the first forming member 20 and the engaging surface 34 of the second forming member 30 face each other, as illustrated in
As illustrated in
As illustrated in
The first forming member 20 then moves in the second direction SD towards the formable material 12, engages the formable material 12 with the engaging surface 24, as illustrated in
Similar to the movement of the first forming member 20 that is represented in
The second forming member 30 then moves in the third direction TD towards the formable material 12, as illustrated in
Similar to the movement of the first forming member 20 illustrated in
The first forming member 20 then moves in the second direction SD towards the formable material 12, as illustrated in
Similar to the movement of the second forming member 30 that is represented in
The second forming member 30 then moves in the third direction TD towards the formable material 12, as illustrated in
The method continues to repeat itself, as illustrated by
As illustrated in
Next, the formable material 12 is provided (i.e., drawn or fed) in the first direction FD by the feeder 14 as the first forming member 20 is moved in the first direction FD at substantially the same rate that the formable material 12 is being provided, and the second forming member 30 is positioned closer to the feeder 14 than the first forming member 20, as illustrated in
As illustrated in
Although the illustrated embodiment shows the wave form being generated on one side of the axis AX, in another embodiment, the positioning of the first and second forming members 20, 30 may be adjusted so that the first and second forming members 20, 30 alternate as to which member is located the closest to the feeder 14 when the formable material 12 is being deformed.
As illustrated in
After the portion of the wave form has been formed, as illustrated in
It has been found that the method of creating the wave form that is illustrated in
The steps illustrated in the embodiment of
For example, the controller 16 may be programmed with the desired wave form and corresponding signals may be communicated to the feeder 14 and the actuators 26, 36 that move the first and second forming members 20, 30, so that the first and second forming members 20, 30 are moved relative to the feeder 14 and the formable member 12 accordingly. The forming apparatus 10 uses multi-axis motions to deform the formable material 12 and create a specific wave form or stent pattern that creates a stent having substantially perpendicular ends when wound about mandrel or other suitable structure. In an embodiment, the forming apparatus uses a multi-slide to create the multi-axis motions, but it is not necessary to use a multi-slide to create such motions. Other arrangements are contemplated to be within the scope of the invention.
The formable material 12 may be a wire or strip material that plastically deforms when deformed by the first and second forming members 20, 30 so that the wave form generally holds its shape after being formed. By adjusting the shape and size of the first and second forming members 20, 30, the relative motions of the first and second forming members 20, 30 in relation to each other, the formable material 12, and the feed rate or draw rate and/or movement of the feeder 14, various amplitudes, periods, and shapes may be created within the wave form to form the overall desired shape for the stent.
Embodiments of the stents made using the method and apparatus discussed above may be formed from a wire or a strip of suitable material. In certain embodiments, the stents may be formed, i.e., etched or cut, from a thin tube of suitable material, or from a thin plate of suitable material and rolled into a tube. Suitable materials for the stent include but are not limited to stainless steel, iridium, platinum, gold, tungsten, tantalum, palladium, silver, niobium, zirconium, aluminum, copper, indium, ruthenium, molybdenum, niobium, tin, cobalt, nickel, zinc, iron, gallium, manganese, chromium, titanium, aluminum, vanadium, and carbon, as well as combinations, alloys, and/or laminations thereof. For example, the stent may be formed from a cobalt alloy, such as L605 or MP35N®, Nitinol (nickel-titanium shape memory alloy), ABI (palladium-silver alloy), Elgiloy® (cobalt-chromium-nickel alloy), etc. It is also contemplated that the stent may be formed from two or more materials that are laminated together, such as tantalum that is laminated with MP35N®. The stents may also be formed from wires having concentric layers of different metals, alloys, or other materials. Embodiments of the stent may also be formed from hollow tubes, or tubes that have been filled with other materials. The aforementioned materials and laminations are intended to be examples and are not intended to be limiting in any way.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of members described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
Claims
1. A method for forming a wave form for a stent, the method comprising:
- providing a length of a formable material from a supply of the formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member, the second forming member being positioned closer to the feeder than the first forming member;
- moving a distal end of the first forming member across the axis in a second direction substantially perpendicular to the first direction to engage and deform the formable material while engaging the formable material with a distal end of the second forming member;
- moving the distal ends of the first and second forming members across the axis in a third direction that is substantially opposite the second direction to draw and form the formable material over the distal end of the second forming member;
- disengaging the first forming member from the forming material;
- moving the first forming member and the second forming member relative to each other so that the first forming member is positioned closer to the feeder than the second forming member;
- moving the distal end of the first forming member into engagement with the deformable material; and
- moving the distal ends of the first and second forming members across the axis in the second direction to draw and form the formable material over the distal end of the first forming member.
2. The method according to claim 1, wherein the distal ends of the first and second forming members each comprise an engaging surface for engaging the formable member, and wherein each engaging surface is shaped to form a curved portion between two substantially straight portions in the wave form.
3. The method according to claim 1, wherein an amount of movement of the distal ends of the first and second forming members relative to the axis substantially determines a length of a substantially straight portion of the wave form.
4. The method according to claim 1, further comprising
- disengaging the second forming member from the forming material;
- moving the first forming member and the second forming member relative to each other so that the second forming member is positioned closer to the feeder than the first forming member;
- moving the distal end of the second forming member into engagement with the deformable material; and
- moving the distal ends of the first and second forming members across the axis in the third direction to draw and form the formable material over the distal end of the second forming member.
5. The method according to claim 1, wherein the providing comprises drawing a length of the formable material with the first forming member and/or the second forming member.
6. A method for forming a wave form for a stent, the method comprising:
- providing a length of a formable material from a supply of the formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member, the second forming member being positioned closer to the feeder than the first forming member, the length being about the length of a substantially straight portion of the wave form;
- moving the first forming member in a second direction substantially perpendicular to the first direction to a position in contact with the formable material; and
- moving the second forming member in a third direction substantially opposite the second direction to wrap the formable material about a distal end of the first forming member.
7. The method according to claim 6, further comprising moving the first forming member and/or the second forming member to adjust a wavelength of a portion of the wave form.
8. The method according to claim 7, wherein the first forming member and the second forming member are moved closer to one another to shorten the wavelength of the portion of the wave form.
9. The method of claim 6, further comprising
- moving the first forming member in the third direction and the second forming members in the second direction to disengage the first and second forming members from the formable material;
- moving the first forming member in a direction opposite the first direction and towards the feeder so that the first forming member is positioned closer to the feeder than the second forming member;
- moving the distal end of the first forming member into engagement with the deformable material;
- providing a second length of the formable material along the axis in the first direction while moving the first forming member in the first direction; and
- moving the second forming member in the third direction to wrap the formable material about the distal end of the first forming member.
10. The method according to claim 9, wherein the length and the second length are substantially the same.
11. The method according to claim 9, wherein the length and the second length are different.
12. The method according to claim 9, wherein the providing the second length of the formable material comprises drawing the formable material with the first forming member and/or the second forming member.
13. A method for forming a wave form for a stent, the method comprising:
- providing a length of a formable material from a supply of the formable material in a feeder along an axis in a first direction in between a first forming member and a second forming member, the second forming member being positioned closer to the feeder than the first forming member;
- moving the first forming member into contact with the formable material and across the axis in a second direction substantially perpendicular to the first direction; and
- folding the formable material over the second forming member by moving the second forming member and the first forming member in a third direction substantially opposite the second direction and moving the second forming member and the first forming member in a fourth direction substantially opposite the first direction.
14. The method according to claim 13, further comprising
- moving the first forming member so that the first forming member is positioned closer to the feeder than the second forming member;
- drawing a length of the formable member from the feeder with the first forming member and the second forming member; and
- folding the formable material over the first forming member by moving the first forming member and the second forming member in the second direction and moving the first forming member and the second forming member in the fourth direction.
15. The method according to claim 13, wherein the second forming member and the first forming member are moved in the third direction and then are moved in the fourth direction sequentially.
16. The method according to claim 13, wherein the second forming member and the first forming member are moved in the third direction and in the fourth direction simultaneously.
17. A forming apparatus configured to form a wave form for a stent out of a formable material, the wave form comprising a plurality of substantially straight portions and a plurality of curved portions, the apparatus comprising:
- a feeder constructed and arranged to receive a supply of the formable material and to provide the formable material along an axis;
- a first forming member configured to be movable along two orthogonal axes, the first forming member comprising a first elongated portion having a first engaging surface at a distal end of the first elongated portion, the first engaging surface being configured to engage a first side of the formable material;
- a second forming member configured to be movable along the two orthogonal axes, the second forming member comprising a second elongated portion having a second engaging surface at a distal end of the second elongated portion, the second engaging surface being configured to engage a second side of the formable material that is opposite the first side; and
- a controller in communication with the feeder, the first forming member, and the second forming member, the controller being configured to control movement of the first and second forming members to control a length of each substantially straight portion of the wave form and to control a wavelength within the wave form.
18. The forming apparatus according to claim 17, further comprising a first actuator in communication with the controller and configured to move the first forming member, and a second actuator in communication with the controller and configured to move the second forming member.
19. The forming apparatus according to claim 17, wherein the formable material is a wire.
20. The forming apparatus according to claim 17, wherein the formable material is a strip of material.
Type: Application
Filed: Jan 26, 2010
Publication Date: Mar 24, 2011
Applicant: Medtronic Vascular, Inc. (Santa Rosa, CA)
Inventor: Erik Griswold (Penngrove, CA)
Application Number: 12/693,574
International Classification: B21F 3/02 (20060101); B21F 45/00 (20060101); B21F 1/04 (20060101);