Apparatus for gripping and holding diagnostic cassettes
View Patent ↗The apparatus is a mechanism for acquiring, holding, and enabling the movement of a cassette-shaped article, such as a reagent or sample cassette, which may be part of an automated diagnostic analyzer, such that the apparatus can tolerate a significant degree of cassette misplacement and/or misalignment during the acquisition maneuver. The mechanism furthermore enables simultaneous two-dimensional movement of the acquiring gripper jaws such that the inter-jaw distance decreases at the same time as movement in an upward vertical direction is provided while the jaw movement is adequately smooth so as not to disturb the physical state of the sample.
1. An apparatus for gripping a cassette-shaped article comprising;
a support housing;
a linear actuator movable along an x-axis relative to the support;
a set of jaws for gripping the cassette-shaped article, each jaw having a proximal end and a distal end, the distal end being adapted for gripping the cassette-shaped article;
a movable node located at the proximal end of each jaw for connecting each jaw to the linear actuator;
a fixed node relative to the support located between the proximal and distal end of each jaw for connecting each of the jaws to the support, wherein the fixed node is indirectly located on the jaws and is connected to the jaws via linkage and a movable node on the jaws; and wherein movement of the linear actuator provides motion to the movable node in an x- and y-axis thereby rotating the jaws around the fixed node resulting in the jaws opening and closing; and
a sector gear linkage having a toothed side and a linkage extending away from the toothed side, the end of the linkage opposite the sector gear linkage connected to the movable node; and a rack on the linear actuator, wherein the sector gear linkage teeth and the rack teeth are engaged and where movement of the rack rotates the sector gear linkage imparting motion to the linkage which imparts motion to the jaws through the movable node.
2. An apparatus according to claim 1 , wherein the linear actuator comprises a motor and a rotatable lead screw driven by said motor.
3. An apparatus for gripping a cassette-shaped article comprising;
a support housing;
a linear actuator movable along an x-axis relative to the support;
a set of jaws for gripping the cassette-shaped article, each jaw having a proximal end and a distal end, the distal end being adapted for gripping the cassette-shaped article;
a movable node located at the proximal end of each jaw for connecting each jaw to the linear actuator;
a fixed node relative to the support located between the proximal and distal end of each jaw for connecting each of the jaws to the support, wherein the fixed node is indirectly located on the jaws and is connected to the jaws via linkage and a movable node on the jaws; and wherein movement of the linear actuator provides motion to the movable node in an x- and y-axis thereby rotating the jaws around the fixed node resulting in the jaws opening and closing;
a set of registration dowels;
a compliance block; and
a spring;
wherein acquisition of the cassette is guided by the registration dowels and the movement of the cassette-shaped article is guided by the compliance block and spring allowing for possible misalignment of the apparatus relative to the cassette-shaped article.
4. An apparatus according to claim 3 , further wherein the set of registration dowels are attached to the bottom of the housing near the distal end of each of the jaws and which are positioned to be capable of being abutted by the cassette-shaped article once the cassette-shaped article has been acquired, wherein the compliance block is located at the upper end of the housing and the spring is placed under the compliance block, enabling the housing to deflect.
5. An apparatus for gripping a diagnostic cassette comprising:
a housing,
a servo motor,
a rotatable lead screw driven by said motor,
a rack nut,
a sector gear linkage, and
a set of jaws,
wherein the application of electromotive force to the servo motor causes rotation of the lead screw in a first direction which imparts linear motion to the rack nut in a first direction resulting in rotational movement of the sector gear linkage in the opposite direction producing an inward rotation of the set of jaws to a predetermined point which allows the diagnostic cassette to be gripped by the jaws, and
wherein upon gripping the cassette, the set of jaws are retracted upward into the housing.
6. A method for gripping a cassette-shaped article comprising;
providing a support housing;
providing a linear actuator movable along an x-axis relative to the support;
providing a set of jaws for gripping the cassette-shaped article, each jaw having a proximal end and a distal end, the distal end being adapted for gripping the cassette-shaped article;
providing a movable node located at the proximal end of each jaw for connecting each jaw to the linear actuator;
providing a fixed node relative to the support located between the proximal and distal end of each jaw for connecting each of the jaws to the support, wherein the fixed node is indirectly located on the jaws and is connected to the jaws via linkage and a movable node on the jaws;
positioning the housing to be located above the cassette-shaped article to be gripped;
moving the linear actuator which provides motion to the movable node in an x- and y-axis thereby rotating the jaws around the fixed node resulting in the jaws closing and acquiring the cassette-shaped article; and
a sector gear linkage having a toothed side and a linkage extending away from the toothed side, the end of the linkage opposite the sector gear linkage connected to the movable node; and a rack on the linear actuator, wherein the sector gear linkage teeth and the rack teeth are engaged and where movement of the rack rotates the sector gear linkage imparting motion to the linkage which imparts motion to the jaws through the movable node.
7. A method according to claim 6 , further comprising
providing a set of registration dowels, attached to the bottom of the housing near the distal end of each of the jaws capable of being abutted by the cassette-shaped article once the cassette-shaped article has been acquired,
providing a compliance block, located at the upper end of the housing, and a spring, placed under the compliance block, enabling the housing to slightly tilt,
wherein acquisition of the cassette is guided by the registration dowels and the movement of the cassette-shaped article is guided by the compliance block and spring allowing for possible misalignment of the apparatus relative to the cassette-shaped article.