Apparatus for detecting limits of travel
AssigneeGerber Scientific, Inc.
InventorDavid J. Logan
Life of this patent
Estimating the term…
Abstract
A motor driven plotter has a plotting head which is translated in two coordinate directions over the work surface of a plotting table. The plotting head is mounted on a first carriage which moves in one coordinate direction and a second carriage is mounted on the first for movement in the second coordinate direction. The limits of both carriages in each coordinate direction are directed by means of a pull cord suspended in a rectangular pattern from the first carriage. A cord portion or segment is intersected and extended by a contact at each limit of travel in the coordinate directions. A switch connected to the cord produces a limit signal when the cord is extended.
Claims12
A machine producing relative movements between a tool and a workpiece comprising:
- a work table for holding a workpiece;
- a work tool for operating upon the workpiece on the table;
- first movable means connected between the work table and tool for moving the tool and workpiece relative to one another in one coordinate direction between two opposite limits of travel;
- second movable means connected between the work table and tool for moving the tool and workpiece relative to one another in another coordinate direction between another two opposite limits of travel;
- limit detecting means for detecting relative movement of the tool and workpiece at each of said limits of travel and producing a limit signal including a pull cord suspend at a plurality of spaced points to form a plurality of interconnected and angularly disposed cord segments, a plurality of cord contacts disposed to intersect and change the length of at least one cord segment at each of said limits of travel, and a switch connected with the pull cord and actuated to produce the limit signal by extension of any one of the cord segments at a limit of travel.
In a machine having first and second carriages for positioning a tool over the work surface of a table having predefined limits, the first carriage being movable in a first coordinate direction between opposite limits of the table work surface and the second carriage being mounted on the first and movable in the second coordinate direction between other opposite limits of the table work surface, the tool being mounted on the second carriage for movement in both coordinate directions, an improved limit detecting apparatus comprising:
- a nonelastic cord suspended from at least four points and forming a plurality of interconnected, angularly arranged cord sections extending generally parallel to the work surface of the table, two sections extending at angles to the second coordinate direction, and at least one section extending at an angle to the first coordinate direction, first means responsive to movement of the first carriage at one limit of the work surface for intersecting and lengthening said other section and thereby pulling the nonelastic cord;
- second means responsive to movement of the second carriage on the first at another limit of the work surface for intersecting and lengthening one of said two sections and thereby pulling the nonelastic cord;
- and third means responsive to movement of the second carriage on the first at still another limit of the work surface for intersecting and lengthening the other of said two sections and thereby pulling the cord;
- and switching means connected with the cord and responsive to any pulling of the cord for tripping the switch and providing a limit signal.
A machine producing relative movements between a tool and a workpiece comprising:
- a work tool and a work table for holding a workpiece as it is operated upon by the tool;
- means for moving the tool and the workpiece mounted on the table relative to one another in at least one coordinate direction between two opposite limits of travel;
- and limit detecting means for detecting relative movement of the tool and workpiece at said limits of travel and producing a limit signal, said detecting means including a pull cord suspended to form a plurality of interconnected cord segments associated with the opposite limits of travel, means connected with and resiliently tensioning the suspended pull cord and a plurality of cord contacts associated with the limits of travel for engaging respectively cooperative cord segments and pulling the cord in opposition to the resilient tension as relative movement takes place between the tool and workpiece at the associated limits of travel, the detecting means also including a switch means connected to the pull cord for actuation and generation of a limit signal when any segment of the cord is intercepted and pulled by a contact at a limit of travel.
Dependencies are inferred from the claim text.