1. A method of molding an article, said method comprising the steps of:
providing a mold, said mold including a mold channel having an opening therein;
sliding a mold plate in a direction parallel to said mold channel and into a first position within said mold, wherein in said first position said mold plate extends through said opening and into said channel to create an undercut feature in said article;
placing a material within said mold to create said article;
molding said article from said material, wherein said molding of said article includes heating said material in said mold and rotating said mold;
sliding said mold plate in a direction parallel to said mold channel and into a second position within said mold, wherein in said second position said mold plate does not extend into said channel through said opening; and
removing said molded article from said mold, said article containing an undercut feature.
2. The method of claim 1 wherein said mold plate has an edge portion, said edge portion having a mold edge and a recessed edge; and
wherein in said first position said mold edge extends through said opening into the mold channel to create said undercut feature and in said second position said recessed edge is in alignment with, and does not extend through, said opening such that a molded article having an undercut feature may be removed from said mold channel.
3. The method of claim 1 wherein said mold has a plurality of adjacent mold channels to create a plurality of molded features in an article.
4. The method of claim 1 wherein said mold channel has a plurality of openings in said channel to create a series of undercut features in a molded article.
5. A method of molding an article, said method comprising the steps of:
providing a mold, said mold including a mold channel defined by opposed first and second sidewalls, at least one of said sidewalls having an opening therein;
selecting between a first position in which a mold plate extends through said opening in one of said sidewalls into said channel and towards the other of said sidewalls to create an undercut feature in said article and a second position in which said mold plate does not extend through said opening and into said channel so that an undercut feature is not created in said article;
placing a material within said mold to create said article;
molding said article from said material, said step of molding said article including heating said material in said mold and rotating said mold; and
removing said molded article from said mold.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system for determining linear position, the system comprising:
a magnet having a first magnetic pole and a second magnetic pole, wherein the first magnetic pole and the second magnetic pole define an axis of the magnet; and
a magnetoresistive sensor comprising a magnetoresistive sensor structure that includes a Wheatstone bridge circuit including a plurality of anisotropic magnetoresistors, the magnetoresistive sensor structure defining a plane that, in the system, is oriented out-of-plane with the axis of the magnet,
wherein, in operation, the magnet travels, with respect to the magnetoresistive sensor, along a substantially linear path of travel that is substantially parallel to the plane defined by the sensor structure, such that the sensor operates in a saturation mode when the magnet is located along a given portion of the path of travel and, when operating in the saturation mode, the magnetoresistive sensor produces an electrical signal that corresponds with a linear position of the magnet along the given portion of the path of travel, the electrical signal approximates a third order polynomial and includes only a single mid-point crossing as the magnet travels along the given portion of the path of travel in a single direction.
2. The system of claim 1, wherein the plane defined by the sensor structure is substantially perpendicular to the axis of the magnet.
3. The system of claim 1, wherein the path of travel is arranged along a line that is a first distance from an approximate center of the magnetoresistive sensor structure in a first Cartesian coordinate axis and a second distance from the first Cartesian coordinate axis in a second Cartesian coordinate axis.
4. The system of claim 3, wherein the first distance is measured in the plane defined by the magnetoresistive sensor structure and the second distance is measured along a line that is orthogonal to the plane defined by the magnetoresistive sensor structure.
5. The system of claim 1, wherein the plurality of magnetoresistors comprise ferrous materials.
6. The system of claim 1, wherein the Wheatstone bridge circuit comprises four magnetoresistors arranged in a diamond-shaped pattern, wherein each side of the diamond-shaped pattern includes a single one of the four resistors.
7. The system of claim 1, further comprising signal conditioning circuitry for receiving the electrical signal from the magnetoresistive sensor and converting the electrical signal to a linear position of the magnet along the given portion of the path of travel.
8. A system for determining linear position, the system comprising:
a magnet having a first magnetic pole and a second magnetic pole, wherein the first magnetic pole and the second magnetic pole define an axis of the magnet; and
a plurality of magnetoresistive sensors, each of the plurality of magnetoresistive sensors including a magnetoresistive sensor structure that includes a Wheatstone bridge circuit including a plurality of anisotropic magnetoresistors, each magnetoresistive sensor structure defining a respective plane, the defined planes of the magnetoresistive sensor structures being oriented out-of-plane with the axis of the magnet in a substantially coplanar fashion with one another, the plurality of magnetoresistive sensors being arranged along a first line and having substantially the same angular orientation with respect to one another,
wherein, in operation:
the magnet travels, with respect to the magnetoresistive sensors, along a substantially linear path of travel that is substantially parallel to (i) the respective planes defined by the sensor structures and (ii) the first line;
at least one of the magnetoresistive sensors of the plurality operates in a saturation mode when the magnet is located along a particular portion of the path of travel; and
when operating in the saturation mode, the magnetoresistive sensors each produce an electrical signal that corresponds with a linear position of the magnet along the particular portion of the travel path, each electrical signal approximating a third order polynomial and having only a single mid-point crossing as the magnet travels, in a single direction, along the particular portion of the path of travel corresponding with each respective electrical signal.
9. The system of claim 8, wherein the planes defined by the sensor structures are substantially perpendicular to the axis of the magnet.
10. The system of claim 8, wherein the path of travel is arranged along a second line, the second line being a first distance from the first line in a first Cartesian coordinate axis and a second distance from the first Cartesian coordinate axis in a second Cartesian coordinate axis.
11. The system of claim 8, further comprising signal conditioning circuitry for receiving the respective electrical signals from the plurality of magnetoresistive sensors and determining a linear position of the magnet along the particular portion of the path of travel based on the electrical signals.
12. A method for detecting linear position comprising:
providing a magnet having a first magnetic pole and a second magnetic pole, wherein the first magnetic pole and the second magnetic pole define an axis of the magnet;
providing a magnetoresistive sensor comprising a magnetoresistive sensor structure that includes a Wheatstone bridge circuit including a plurality of anisotropic magnetoresistors, the magnetoresistive sensor structure defining a plane that is oriented out-of-plane with the axis of the magnet; and
receiving an electrical signal produced by the magnetoresistive sensor, the electrical signal corresponding with a linear position of the magnet along a given portion of a path of travel, the path of travel being substantially parallel with the plane, wherein the magnetoresistive sensor operates in a saturation mode when the magnet is located along the given portion of the path of travel and wherein the electrical signal produced by the magnetoresistive sensor approximates a third order polynomial and includes only a single mid-point crossing as the magnet travels along the given portion of the path of travel in a single direction.
13. The method of claim 12, wherein the plane defined by the sensor structure is substantially perpendicular to the axis of the magnet.
14. The method of claim 12, wherein the electrical signal produced by the magnetoresistive sensor comprises an analog signal and the method further comprises:
amplifying the analog signal;
converting the analog signal to a digital value; and
determining the linear position of the magnet along the given portion of the path of travel based on the digital value.