Patent Application
20130093545
The present invention generally relates to magnetically operated switches, and more particularly relates to a magneto-resistance quadrupole magnetic coded switch.
Various types of switches have been implemented to provide protection to both systems and personnel. Such switches, when provided, ensure that electrical power is available to at least certain portions of a system only when certain components are in predetermined positions with respect to each other. For example, one or more switches may be included in a system to ensure that separately driven parts of the system do not collide with each other.
Such switches may also be used to provide electrical power to energize one portion of a system only when a second portion is out of the path of a first portion. These switches may also be used to ensure that a machine or system operator is not within the vicinity of certain parts of a machine or system, such as in cutting, grinding, forging, or punching machines or systems, before power is made available to drive these parts.
The above-described switches have been variously implemented and configured. In many instances, these switches are mechanically or magnetically operated devices. While reliable, presently known mechanically and magnetically operated switches do exhibit certain drawbacks. For example, presently known mechanically and magnetically operated switches may be readily overridden by an operator in the interest of faster machine or system operation.
Hence there is a need for a tamper resistant switch and/or a switch that is not readily overridden, to ensure adequate levels of safety margin for machines and machine operators. The instant invention addresses at least this need.
In one embodiment, a quadrupole magnetic coded switch includes a switch housing, an actuator housing, a first pair of actuator dipole magnets, a first pair of switch dipole magnets, and a pair of first magneto-resistance (MR) sensors. The actuator housing is movable relative to the switch housing. The first pair of actuator dipole magnets is coupled to the actuator housing and is movable therewith, and the first pair of switch dipole magnets is coupled to the switch housing. The first pair of actuator dipole magnets and the first pair of switch dipole magnets are arranged to generate a first quadrupole magnetic field. Each of the first MR sensors is disposed within the switch housing and is configured to vary in resistance in response to relative movement of the actuator housing and the switch housing.
In another embodiment, a magneto-resistance quadrupole magnetic coded switch system includes a switch housing, an actuator housing, a first pair of actuator dipole magnets, a first pair of switch dipole magnets, a pair of first magneto-resistance (MR) sensors, and processing circuitry. The actuator housing is movable relative to the switch housing. The first pair of actuator dipole magnets is coupled to the actuator housing and is movable therewith. The first pair of switch dipole magnets is coupled to the switch housing. The first pair of switch dipole magnets and the first pair of actuator dipole magnets are arranged to generate a first quadrupole magnetic field. Each of the first MR sensors is disposed within the switch housing and is configured to vary in resistance in response to relative movement of the actuator housing and the switch housing. The processing circuitry is coupled to the first MR sensors and is configured, in response to variations in the resistance of the first MR sensors, to supply one or more switched output signals.
Furthermore, other desirable features and characteristics of the magneto-resistance quadrupole magnetic coded switch will become apparent from the subsequent detailed description, taken in conjunction with the accompanying drawings and this background.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Thus, any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. 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.
A functional schematic diagram of an embodiment of a quadrupole magnetic coded switch is depicted in
The switch assembly 104 includes a switch housing 112, plural pairs of dipole magnets 114, which are referred to herein as pairs of switch dipole magnets, and plural pairs of magneto-resistive (MR) sensors 116. The pairs of switch dipole magnets 114 are each coupled to the switch housing 112 and, in the depicted embodiment, includes three pair of switch dipole magnets—a first pair of switch dipole magnets 114-1 (SM1, SM2), a second pair of switch dipole magnets 114-2 (SM3, SM4), and a third pair of switch dipole magnets 114-3 (SM5, SM6). It will be appreciated that in other embodiments the switch assembly 104 could be implemented with more or less than this number of pairs of switch dipole magnets 114. As with the actuator dipole magnets 108, although the switch dipole magnets 114 are preferably implemented using permanent magnets, electromagnets could also be used.
No matter the specific number of pairs of actuator dipole magnets 108 and pairs of switch dipole magnets 114, each of these dipole magnets 108, 114, as is generally known, includes a north pole (N) and a south pole (S). The actuator and switch dipole magnets 108, 114 also each include a magnetic axis 110, which is defined herein as a line that extends through the center of the magnets 108, 114 and through the north (N) and south (S) poles thereof. As
Before proceeding further, it is noted that the actuator assembly 102 is preferably movable relative to the switch assembly 104. Thus, in most embodiments the actuator housing 106 is coupled to a movable portion of a particular device, system, or machine such as, for example, a machine guard, a door, or any one of numerous other movable portions. Concomitantly, the switch housing 112 is preferably coupled to a stationary portion of the same particular device, system, or machine as the actuator housing 106.
The pairs of MR sensors 116 are disposed within the switch housing 112. As will be described momentarily, each MR sensor 116 is configured to vary in resistance in response to the relative movement of the actuator housing 106 and the switch housing 112, and more specifically based on the relative strength of the quadrupole magnetic fields. Although the number of MR sensors 116 may vary, in the depicted embodiment the switch assembly 104 includes three pair of MR sensors 116—a pair of first MR sensors 116-1 (S1, S2), a pair of second MR sensors 116-2 (S3, S4), and a pair of third MR sensors 116-3 (S5, S6)—with each pair of MR sensors 116 being associated with one pair of actuator dipole magnets 108 and one pair of switch dipole magnets 114. In particular, the pair of first MR sensors 116-1 is associated with the first pair of actuator dipole magnets 108-1 and the first pair of switch dipole magnets 114-1, the pair of second MR sensors 116-2 is associated with the second pair of actuator dipole magnets 108-2 and the second pair of switch dipole magnets 114-2, and the pair of third MR sensors 116-3 is associated with the third pair of actuator dipole magnets 108-3 and the third pair of switch dipole magnets 114-3.
It will be appreciated that the MR sensors 116 may be implemented using any one of numerous types of MR sensors. For example, the MR sensors 116 may be implemented using AMR (anisotropic magneto-resistance) sensors or GMR (giant magneto-resistance) sensors. In the depicted embodiments, however, the MR sensors 116 are each implemented using AMR sensors, which may be either single-axis or two-axis AMR sensors. Embodiments of single-axis and two-axis AMR sensors 200, 300 are depicted in
The exemplary single-axis AMR sensor 200 that is depicted in
The depicted AMR sensor 200 includes four resistive elements, with opposing resistive elements (e.g., 202-1 and 202-3, 202-2 and 202-4) being identical. The AMR sensor 200 additionally includes two input terminals 208-1, 208-2 and two output terminals 212-1, 212-2. Preferably, an electric power source 214, such as a regulated DC voltage source, is coupled across the two input terminals 208-1, 208-1. Thus, if a positive magnetic field is applied in the magnetic sensitive axis 204, meaning a magnetic field in the magnetic sensitive axis 204 and in the direction in which arrow 204 is pointing, then resistive elements 202-1 and 202-3 will increase in resistance and resistive elements 202-2 and 202-4 will decrease in resistance. As a result, the voltage magnitude across the output terminals 212-1, 212-2 will increase, and have a positive polarity. Conversely, if a negative magnetic field is applied in the magnetic sensitive axis 204, meaning a magnetic field in the magnetic sensitive axis 204 and in the direction opposite that which arrow 204 is pointing, then resistive elements 202-1 and 202-3 will decrease in resistance and resistive elements 202-2 and 202-4 will increase in resistance. As a result, the voltage magnitude across the output terminals 212-1, 212-2 will also increase, but have a negative polarity.
The exemplary two-axis AMR sensor 300 depicted in
In the embodiment depicted in
It will be appreciated that the embodiment depicted in
In some embodiments, the switch 100 may additionally include a plurality of interposed MR sensors 502, one associated with each pair of MR sensors 116. Thus, for the embodiments depicted in
The quadrupole magnetic coded switches depicted in FIGS. 1 and 4-6 and described above are each preferably coupled to processing circuitry that is configured, in response to the variations in the resistance of the MR sensors 116, to supply one or more switched output signals. It will be appreciated that the processing circuitry may be variously implemented. One particular implementation of the processing circuitry, in accordance with one embodiment, is depicted in
The depicted processing circuitry 700 includes signal conditioning circuitry 702, logic circuitry 704, and solid state switching circuitry 706. The signal conditioning circuitry 702 is coupled to receive the output signals supplied from each of the MR sensors 116. As may be appreciated, the output signals from the MR sensors 116 are representative of the variations in the resistances of the MR sensors 116, which are in turn representative of the relative proximities of the actuator housing 102 and the switch housing 104. The signal conditioning circuitry 702 is configured to amplify and filter the output signals, and implement suitable threshold or comparison functions to supply logic-level signals (e.g., logic-level HIGH/logical “1” or logic-level LOW/logical “0”) to the logic circuitry 704.
Before describing the remainder of the processing circuitry 700, it was noted above that the MR sensors 116 may be variously disposed within the switch housing 112. For example, the magnetic sensitive axis 204 of each MR sensor in a pair of MR sensors 116 may be disposed in the same direction or in opposite directions. The disposition of the MR sensors may be varied so that its associated output signal, after being processed by the signal conditioning circuitry 702 will be either a logic-level HIGH signal or a logic-level LOW signal when the actuator housing 106 and the switch housing 112 are moved toward, and are within a first predetermined distance of, each other, and will be the opposite logic-level signal when the actuator housing 106 is moved away from, and is a second predetermined distance from, the switch housing 112.
Turning now to the logic circuitry 704, this circuitry receives the logic-level signals from the signal processing circuitry 702 and, implementing any one or combinations of Boolean operations (e.g., AND, OR, NAND, NOR, etc.), supplies switch signals to the solid state switching circuitry 706. The Boolean operations that the logic circuitry 704 implements may vary, and may be selected to supply a first binary output from the logic circuitry 704 when the actuator housing 106 and the switch housing 112 are moved toward, and are within the first predetermined distance of, each other, and supply a second binary output when the actuator housing 106 is moved away from, and is the second predetermined distance from, the switch housing 112.
The solid state switch circuitry 706 is coupled to receive the switch signals and is configured, in response thereto, to selectively turn a plurality of solid state switches ON or OFF. In one particular embodiment, the solid state switches are implemented using MOSFFETs. As such, each of the MOSFETs is placed into a conductive or non-conductive state in response to the switch signals it receives, to thereby supply the one or more switched output signals.
While at least one exemplary embodiment has been presented in the foregoing detailed description, 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 road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention.
