Balanced magnetic switch

Abstract

A magnetic switch assembly detects movement between first and second members. The magnetic switch assembly includes a switch magnet shiftable between first and second positions in a housing for mounting on the first member, a biasing magnet, and an actuator magnet for mounting to the second member. When the first and second members are in an initial relative orientation, ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another, and the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position. When the first and second members are in a different relative orientation where the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position.

Description

BALANCED MAGNETIC SWITCHCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The current patent application is a non-provisional utility patent application which claims priority benefit of earlier-filed U.S. Provisional Application Ser. No. 63 / 735,483; titled “BALANCED MAGNETIC SWITCH”; and filed December 18, 2024. The Provisional Application is hereby incorporated by reference, in its entirety, into the current patent application.BACKGROUND OF THE INVENTION

[0002] Security alarm systems often use magnetic switches attached to doors, windows, or other shiftable barriers that serve as points of entry into a space. The magnetic switches are generally integrated with a system for detecting changes in states of the switches. One type of such switches is a reed switch. However, reed switches are vulnerable to unauthorized manipulation through the use of a defeat magnet. Specifically, an intruder can hold a relatively strong defeat magnet adjacent to a housing of a reed switch to hold a current state of the switch. Doing so, the intruder can then open the barrier to access the protected space without triggering the alarm system.

[0003] Current solutions for inhibiting this include the use of ball switches, such as those described in U.S. Pat. Nos. 5,332,992, 5,530,428, 5,673,021, 5,880,659, 5,977,873, 6,506,987, 6,603,378, 7,023,308, 7,291,794, and 7,825.801, which are hereby incorporated by reference into the present application. These switches typically include a pair of spaced apart switch elements with a shiftable body (e.g., a spherical ball) vertically movable within an upright housing between a first position where the ball is in simultaneous contact with both elements and a second position out of such simultaneous contact. An alarm circuit is operatively coupled with the switch elements so as to detect movement of the body. These switches represent a very significant advance in the art. The Magnasphere Corporation of Waukesha, Wis., has commercialized a series of magnetic switches of this type.

[0004] While magnetic ball switches of this type are greatly superior to reed switches, instances can arise when a very strong defeat magnet can be successfully used against alarm systems containing conventional magnetic ball switches. This may occur when a strong defeatmagnet is strategically placed so as to maintain the ball in its non-alarm switch state during the course of an illegal entry.

[0005] Thus, there is a need for an improved alarm system that further inhibits the ability of intruders to use increasingly stronger defeat magnets to cause an alarm system to fail. This background discussion is intended to provide information related to the present invention which is not necessarily prior art.SUMMARY OF THE INVENTION

[0006] Embodiments of the current invention address one or more of the above-mentioned problems and provide a distinct advance in the art of magnetic switches actuated by changing relative positions of magnets based on a change in magnetic field.

[0007] One embodiment of the invention is a magnetic switch assembly for detecting relative movement between first and second members. The magnetic switch assembly includes a housing, a switch magnet, a biasing magnet, and an actuator magnet. The housing is for mounting to the first member. The switch magnet is housed in the housing and is shiftable between a first position and a second position. The biasing magnet is for mounting to the first member. The actuator magnet is for mounting to the second member and is arranged so that when the first and second members are in an initial relative orientation, ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another.

[0008] The biasing magnet is selected and arranged so that the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position when the first and second members are in the initial relative orientation, and when the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position. This inhibits the use of a defeat magnet to bypass the magnetic switch assembly. If a defeat magnet of sufficient magnetic strength is positioned proximal to the switch magnet when the first and second members are in the initial relative orientation, the magnetic field of the defeat magnet shifts the magnetic switch to the second position. If the defeat magnet is positioned proximal to the switch magnet when the first and second members are in the different relative orientation, an intruder is less likely to be able to position and hold the defeat magnet in alocation that sufficiently simulates the magnetic field and strength of the actuator magnet so that the magnetic switch does not shift to the first position.

[0009] Another embodiment of the invention is a method of detecting relative movement between first and second members. The method includes securing a housing to the first member. The housing holds a switch magnet that is shiftable between first and second positions within the housing. The method further includes securing an actuator magnet to the second member; securing a biasing magnet to the first member at a location that is between the switch magnet and the actuator magnet when the first and second members are in an initial relative orientation and oriented so that ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another. The biasing magnet is selected and arranged so that the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position when the first and second members are in the initial relative orientation. When the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position. The method further includes detecting, via a circuit, a position of the switch magnet.

[0010] Another embodiment of the invention is a magnetic switch assembly for detecting relative movement between first and second members. The magnetic switch assembly includes a housing, a switch magnet, a biasing magnet, and an actuator magnet. The housing is for mounting to the first member. The switch magnet is housed within the housing and has a first magnetic pole and a second magnetic pole. The switch magnet is shiftable between a first position within the housing in which the first magnetic pole is oriented in a first direction and a second position within the housing in which the first magnetic pole is oriented in a second direction that is different than the first direction. The biasing magnet is for mounting to the first member and has first and second magnetic poles. The actuator magnet is for mounting to the second member and has first and second magnetic poles. The first magnetic pole of the actuator magnet has the same magnetic polarity as the first magnetic pole of the biasing magnet. The actuator magnet is selected and arranged so that when the first and second members are in an initial relative orientation, the first magnetic pole of the actuator magnet is proximal to the first magnetic pole of the biasing magnet and the second magnetic pole of the actuator magnet is distal to the first magnetic pole so that a magnetic field of the actuator magnet orients the first magnetic pole of the switch magnet in thefirst direction, and so that the second magnetic pole of the switch magnet is repelled by the second magnetic pole of the biasing magnet to shift the switch magnet to the first position. The biasing magnet is selected and arranged so that when the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position.

[0011] Another embodiment of the invention is a magnetic switch assembly for detecting positions of a first member relative to a second member. The magnetic switch assembly includes a housing, a switch magnet, a biasing magnet, and an actuator magnet. The housing is for mounting to the first member. The switch magnet is housed in the housing and is shiftable between a first position and a second position. The actuator magnet is for mounting to the second member and is arranged so that when the first and second members are in a first relative orientation wherein the actuator magnet is within a first threshold distance but beyond a second threshold distance from the switch magnet, ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another. The biasing magnet is selected and arranged so that when the first and second members are in the first relative orientation, the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position. When the first and second members are in the second relative orientation wherein the actuator magnet is beyond the first threshold distance from the switch magnet, the biasing magnet shifts the switch magnet to the second position. When the first and second members are in a third relative orientation wherein the actuator magnet is within the second threshold distance from the switch magnet, the actuator magnet shifts the switch magnet to the second position.

[0012] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the current invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.BRIEF DESCRIPTION OF DRAWINGS

[0013] Embodiments of the current invention are described in detail below with reference to the attached drawing figures, wherein:

[0014] FIG. 1 illustrates a preferred magnetic switch assembly in accordance with an embodiment of the invention, depicted in use for protecting a door;

[0015] FIG. 2; is a vertical sectional view depicting the construction and operation of the magnetic switch assembly of FIG. 1 when the door is closed;

[0016] FIG. 3 is a vertical sectional view similar to that of FIG. 2, but illustrating the operation of the magnetic switch assembly when the door is open;

[0017] FIG. 4 is a vertical sectional view similar to that of FIG. 2, but illustrating the operation of the magnetic switch assembly when the door is closed and a defeat magnet is positioned proximal to the magnetic switch assembly;

[0018] FIG. 5 is a vertical sectional view similar to that of FIG. 2, but illustrating the operation of the preferred magnetic switch when the door is open and the defeat magnet is positioned proximal to the magnetic switch assembly;

[0019] FIG. 6 is a vertical sectional view similar to that of FIG. 2, but illustrating the operation of the preferred magnetic switch when an actuator magnet is within a second threshold distance to the switch magnet;

[0020] FIG. 7 is a schematic depiction of an exemplary alarm system using the magnetic switch assembly of FIG. 1; and

[0021] FIG. 8 is a flowchart depicting exemplary steps of a method according to an embodiment of the present invention.

[0022] The drawing figures do not limit the current invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.DETAILED DESCRIPTION OF THE INVENTION

[0023] The following detailed description of the technology references the accompanying drawings that illustrate specific embodiments in which the technology can be practiced. The embodiments are intended to describe aspects of the technology in sufficient detail to enable those skilled in the art to practice the technology. Other embodiments can be utilized and changes canbe made without departing from the scope of the current invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the current invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0024] Turning to FIG. 1. a magnetic switch assembly 10 constructed in accordance with an embodiment of the invention is depicted shown in use with a first member 12, such as a door frame, and a second member 14, such as a door. However, the magnetic switch assembly 10 may be implemented on a window or any other shiftable barrier without departing from the scope of the present invention. The magnetic switch assembly 10 broadly comprises a first portion 16 containing housing with a switch magnet and a biasing magnet (discussed below), which may be secured to the door frame 12, and an actuator magnet 18, which may be secured to the door 14. The actuator magnet 18 may be positioned on the door frame 12, and the first portion 16 may be positioned on the door 14 without departing from the scope of the present invention. One or more appropriate electrical leads 20, 22 are operatively coupled with the magnetic switch assembly 10, as will be described below in more detail.

[0025] Turning to FIG. 2, in one or more embodiments, the first portion 16 includes an enclosure or mounting box 24 that houses the biasing magnet 30 and a switch magnet housing 26, which contains the switch magnet 28. The switch magnet housing 26 has a circumscribing annular wall 32, an integral concavo-convex wall 34, and a cover 36. Preferably, the annular wall 32 presents a circumscribing flange 38, and the annular wall 32 and concavo-convex wall 34 are integrally formed of a suitable electrically conductive material, such as stainless steel or the like. However, the switch magnet housing 26 may be differently shaped without departing from the scope of the present invention. The cover 36 includes an outboard flange 40 adapted to mate with flange 38, and a central nonconductive plug 42, which may be made of any suitable electrically nonconductive material, such as glass, ceramic, or the like. The switch magnet housing 26 further includes a first switch contact 44 which as shown extends through plug 42 to a point spaced apart from wall 34. The internal surfaces of the annular wall 32 and concavo-convex wall 34 serve as second contacts 46.

[0026] The switch magnet 28 is located within housing 26 and is shiftable within the housing 26 between a first position and a second position. In the first position, the switch magnet 28 simultaneously touches both the contacts 44, 46. In one or more embodiments, when in thesecond position, the switch magnet 28 is not simultaneously contacting both contacts 44, 46 (depicted in FIGS. 3-5). This enables the position of the switch magnet 28 to be detected by way of the contacts 44, 46. However, other means may be used to detect a position of the switch magnet 28 without departing from the scope of the present invention. Additionally, it is foreseen that the switch magnet 28 and contacts 44, 46 can be positioned in different arrangements and have different shapes without departing from the scope of the present invention. For example, the contacts 44, 46 can be arranged so that both contacts 44, 46 are contacted by the switch magnet 28 when the switch magnet 28 is in the second position, and when the switch magnet 28 is in the first position, the switch magnet 28 is out of simultaneous contact with the contacts 44, 46.

[0027] In one or more embodiments, the switch magnet 28 comprises permanent magnet material so that the switch magnet 28 produces a magnetic field with first and second magnetic poles. For example, in one or more embodiments, the switch magnet 28 includes a first portion 48 having a first magnetic polarity (such as magnetic North or South), and a second portion 50 having a second magnetic polarity opposite to the first magnetic polarity. The permanent magnet material may include neodymium, samarium cobalt, an appropriate samarium-cobalt alloy with a thin (usually about 25.4 microns to about 50.8 microns) outer coating of nickel for wear purposes, neodymium iron boron, and / or the like. Preferred configurations of switch magnet 28 include substantially spherical balls.

[0028] The biasing magnet 30 is associated with the first portion 16. In the illustrated embodiment, the biasing magnet 30 is secured in the enclosure 24 between the switch magnet housing 26 and the actuator magnet 18 when the first and second members 12, 14 are in their initial proximal relative orientation. In one or more embodiments, the biasing magnet 30 comprises permanent magnet material so that the biasing magnet 30 produces a magnetic field with first and second magnetic poles. For example, in one or more embodiments, the biasing magnet 30 includes a first portion 54 having a first magnetic polarity (such as North or South), and a second portion 56 having a second magnetic polarity opposite to the first magnetic polarity. The biasing magnet 30 may be oriented so that the first portion 54 extends away from the switch magnet 28, and the second portion 56 extends toward the switch magnet 28. As illustrated, the enclosure 24 may be positioned within an appropriately sized recess in frame 12. However, such a mounting arrangement is not essential.

[0029] The actuator magnet 18 is mounted to door 14, preferably along a vertical edge thereof near the top of the door 14. When the door 14 is closed relative to frame 12, or in the initial relative orientation, it will be seen that the actuator magnet 18 is directly in juxtaposition to enclosure 24. Obviously, when the door 14 is opened (depicted in FIG. 3), the actuator magnet 18 is shifted away from the enclosure 24 to a different relative orientation wherein the actuator magnet 18 is remote from the switch magnet 28.

[0030] In one or more embodiments, the actuator magnet 18 comprises permanent magnet material so that the actuator magnet 18 produces a magnetic field with first and second magnetic poles. For example, in one or more embodiments, the actuator magnet 18 includes a first portion 58 having a first magnetic polarity (such as North or South), and a second portion 60 having a second magnetic polarity opposite to the first magnetic polarity. The actuator magnet 18 may be oriented so that the first portion 58 extends towards the biasing magnet 30 and the second portion 60 extends away from the biasing magnet 30 when the first and second members 12, 14 are in the initial relative orientation.

[0031] In one or more embodiments, the ends 58, 54 of the actuator magnet 18 and the biasing magnet 30 that are proximal to one another when the first and second members 12, 14 are in the initial relative orientation have the same magnetic polarity. In other words, the first end 54 of the biasing magnet 30 has the same magnetic polarity as the first end 58 of the actuator magnet 18. For example, the actuator magnet 18 and the biasing magnet 30 may both have their North magnetic poles proximal to one another when the first and second members 12, 14 are in the initial relative orientation with their South magnetic poles being distal from one another, or vice versa. In one or more embodiments, the actuator magnet 18 and the biasing magnet 30 are aligned with one another so that they extend along a shared imaginary axis.

[0032] The actuator magnet 18, switch magnet 28, and biasing magnet 30 are selected and arranged so that when the first and second members 12, 14 are in the initial relative orientation, the magnetic field of the actuator magnet 18 causes the switch magnet 28 to rotate to magnetically align with the actuator magnet 18. For example, if the first end 58 of the actuator magnet 18 is the North magnetic pole, it causes the North magnetic pole of the switch magnet 28, which may be the first portion 48 in this example, to be in the same orientation, e.g., facing away from the actuator magnet 18 and proximal to the cover 36. As a result, the South magnetic pole of the switch magnet 28, which may be the second portion 50, is repelled by the second end 56 of thebiasing magnet 30, which may be the South magnetic pole of the biasing magnet 30, to shift the switch magnet 28 to the first position when the first and second members 12, 14 are in the initial relative orientation. Thus, the first portion 48 of the switch magnet 28 having the first magnetic pole (or North pole in the example) is oriented in a first direction when the switch magnet 28 is in the first position, and the first portion 48 of the switch magnet 28 and therefore the first magnetic pole is oriented in a second direction that is different than the first direction when the switch magnet 28 is in the second position. In one or more embodiments, the first direction is opposite to the second direction.

[0033] Turning to FIG. 3, when the first and second members 12, 14 are in a different relative orientation wherein the actuator magnet 18 is remote from the switch magnet 28, the biasing magnet 30 shifts the switch magnet 28 to the second position. This is due to the relatively stronger magnetic field of the actuator magnet 18 no longer causing the switch magnet 28 to align therewith, thereby allowing the switch magnet 28 to freely rotate. As a result, the magnetic field of the biasing magnet 30 attracts the switch magnet 28 and causes it to rotate so that the first portion 48 having the first magnetic pole of the switch magnet 28 faces the second direction. This causes the switch magnet 28 to shift to the second position.

[0034] Turning to FIG. 4, actuator magnet 18, switch magnet 28, and biasing magnet 30 are selected and arranged so that when a defeat magnet 62 is placed within a threshold distance to the switch magnet 28, the switch magnet 28 shifts to the second position. If the portion 64 of the defeat magnet 62 proximal to the switch magnet 28 has the same magnetic polarity as the portion 58 of the actuator magnet 18 that is also proximal to the switch magnet 28, the added magnetic field increases the strength, or magnetic flux density, of the composite magnetic field proximal to the switch magnet 28, thereby causing it to shift from the first position (depicted in FIG. 2) to the second position, as depicted in FIG. 4.

[0035] If the portion 64 of the defeat magnet 62 proximal to the switch magnet 28 is the opposite magnetic polarity as the portion 58 of the actuator magnet 18 that is also proximal to the switch magnet 28, the defeat magnet 62 at least partially cancels the magnetic field of the actuator magnet 18 so that magnetic flux density proximal to the switch magnet 28 no longer causes the switch magnet 28 to align with the magnetic field of the actuator magnet 18, thereby allowing the switch magnet 28 to rotate and shift from the first position (depicted in FIG. 2) to the second position, as depicted in FIG. 4 due to the attractive magnetic force of the biasing magnet 30. Inboth instances, this enables an alarm circuit to detect the presence of the defeat magnet 62 based on the position of the switch magnet 28.

[0036] Additionally, if an intruder breaks open the door 14 with the defeat magnet 62 in place, as depicted in FIG. 5, it would be difficult to select and position the defeat magnet 62 in a manner that simulates the actuator magnet 18, thereby keeping the switch magnet 28 in the second position.

[0037] FIG. 2 depicts the actuator magnet 18 within a first threshold distance to the switch magnet 28, and FIG. 3 depicts the actuator magnet 18 beyond the first threshold distance to the switch magnet 28. Turning to FIG. 6, in some embodiments the switch assembly 10 may act as a double-throw switch in that when the actuator magnet 18 is within a second threshold distance of the switch magnet 28 (which is a shorter distance than the first threshold distance), the switch magnet 28 shifts to the second position. This is due to the magnetic field of the actuator magnet 18 overcoming the biasing force of the biasing magnet 30, thereby attracting the switch magnet 28 to the second position. Thus, when the actuator magnet 18 shifts back beyond the second threshold distance, the switch magnet 28 shifts back to its first position (as depicted in FIG. 2), and when the actuator magnet 18 shifts beyond the first threshold distance from the switch magnet 28, the switch magnet 28 shifts to its second position (as depicted in FIG. 3).

[0038] This enables detecting multiple positions of the second member 14 relative to the first member 12: a first relative orientation of the second member 14 in which the actuator magnet 18 is closer than the first threshold distance to the switch magnet 28 but farther than the second threshold distance (as depicted in FIG. 2); a second relative orientation of the second member 14 in which the actuator magnet 18 is located beyond the first threshold distance from the switch magnet 28 (as depicted in FIG. 3); and a third relative orientation of the second member 14 in which the actuator magnet 18 is within the second threshold distance to the switch magnet 28 (as depicted in FIG. 6). This enables detecting when the second member 14 is within an upper- and lower-bounded range of distances relative to the first member 12. Specifically, when at the first relative orientation of the second member 14, the first and second threshold serve as proxies for the upper and lower bounds, respectively, of the range of distances between the first and second members 12, 14. It is foreseeable that this operation of the switch assembly 10 may be used in any number of applications without departing from the scope of the present invention.

[0039] The materials used in fabricating the actuator magnet 18 and biasing magnet 30 can be varied, so long as the operational principles of the switch assembly 10 are maintained. For example, and in preferred forms, the actuator magnet 18 and biasing magnet 30 may be formed of a permanently magnetized material. Suitable materials include samarium-cobalt, an appropriate samarium-cobalt alloy, neodymium, neodymium iron boron, and / or the like. As explained in more detail hereafter, the goal in selecting the materials for the actuator magnet 18, switch magnet 28, and biasing magnet 30 is to ensure that the switch magnet 28 may be appropriately magnetically shifted when the door 14 is moved between the closed and open positions thereof.

[0040] In one or more embodiments, the switch magnet 28 has a magnetic flux density that is less than a magnetic flux density of the biasing magnet 30. Additionally, the biasing magnet 30 may have a magnetic flux density that is less than a magnetic flux density of the actuator magnet 18. In one or more embodiments, the magnetic flux density of the switch magnet 28 may be 0.24 to 0.27 Tesla (T). In one or more embodiments, the magnetic flux density of the switch magnet 28 may be 0.2547 T. In one or more embodiments, the magnetic flux density of the biasing magnet 30 may be 0.435 to 0.465 T. In one or more embodiments, the magnetic flux density of the biasing magnet 30 may be 0.452 T. In one or more embodiments, the magnetic flux density of the actuator magnet 18 may be 0.565 to 0.595 T, and in one or more embodiments, the magnetic flux density of the actuator magnet 18 may be 0.5790 T.

[0041] Additionally, in one or more embodiments, the actuator magnet 18, switch magnet 28, and biasing magnet 30 are spaced in accordance with their respective magnetic strengths to achieve the operational principles of the assembly 10. In one or more embodiments, a distance between the biasing magnet 30 and the switch magnet 28 when located in the second position and / or between the biasing magnet 30 and the switch magnet housing 26 may be 0.7 to 0.8 centimeters (cm). In one or more embodiments, this distance may be 0.762 cm. In one or more embodiments, a distance between the biasing magnet 30 and the actuator magnet 18 when the first and second members 12, 14 are in the initial relative orientation may be 3.7 to 3.9 cm, and in one or more embodiments this distance may be 3.81 cm. In one or more embodiments, the threshold distance between the defeat magnet 62 and the biasing magnet 30 is shorter than the distance between the biasing magnet 30 and the actuator magnet 18 when the first and second members are in the initial relative orientation.

[0042] While the present disclosure provides exemplary values or parameters for the magnetic flux densities and spacing of the magnets, these values and parameters may be adjusted without departing from the scope of the present invention.

[0043] In one or more embodiments, the magnetic switch assembly 10 optionally includes one or more magnetic ferrous shunts around the switch magnet 28 to isolate the switch magnet 28 from other magnetic sources. In one or more embodiments, the magnetic ferrous shunts may be positioned on surfaces of the switch magnet housing 26 and / or the enclosure 24 that face away from the switch magnet 28 and / or the biasing magnet 30. For example, the shunts may be positioned on interior or exterior surfaces of the enclosure 24 except for the surfaces between the biasing magnet 30 and the actuator magnet 18.

[0044] FIG. 7 illustrates a conventional hookup of the switch assembly 10 within an alarm circuit 66. The alarm circuit 66 is configured to detect when the switch magnet 28 is in the first position and / or second position. In particular, the switch magnet housing 26 is electrically coupled with a conventional alarm control 68, that is lead 22 is operatively coupled with the first contact 44 and lead 20 is coupled with the second contact 46, with both leads connected to the control 68. The alarm circuit 66 in the illustrated embodiment is configured so that when door 14 is closed, the switch magnet 28 is in the first position (as depicted in FIG. 2), and no alarm signal is generated. However, when the door 14 is opened, or a defeat magnet 62 is positioned proximal to the switch magnet 28, the switch magnet 28 is shifted to the second position (as depicted in FIGS. 3-5), and an alarm signal is generated. An alarm bell 70 or similar output device is typically connected with control 68.

[0045] It will thus be appreciated that if an intruder uses the defeat magnet 62 in an attempt to defeat switch assembly 10 while the door 14 is closed, the switch magnet 28 is moved because of the magnetic attraction between such external magnet to the FIG. 4 position. Specifically, the defeat magnet 62 placed adjacent frame 12 in proximity to switch assembly 10 when door 14 is closed will have the effect of shifting the switch magnet 28 to the second position out of simultaneous contact with switch elements 44, 46. Consequently, any such attempt to defeat the switch assembly 10 will immediately set off the alarm 70.

[0046] The flow chart of FIG. 8 depicts the steps of an exemplary method 800 of detecting relative movement between first and second members. In some alternative implementations, the functions noted in the various blocks may occur out of the order depicted in FIG. 8. For example,two blocks shown in succession in FIG. 8 may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order depending upon the functionality involved. In addition, some steps may be optional. For ease of reference,

[0047] Referring to step 802, securing the first portion to the first member. This step may include positioning the switch magnet housing containing the switch magnet within the enclosure. The first portion may be positioned proximal to an edge of a frame, or the like, so that it is proximal to the second member.

[0048] Referring to step 804, the actuator magnet is secured to the second member. The actuator magnet may be secured to the second member so that it is proximal to the first portion when the first and second members are in the initial relative orientation. The actuator magnet may be positioned so that it extends along an imaginary axis extending through the switch magnet when the switch magnet is in the second position.

[0049] Referring to step 806, the biasing magnet is secured to the first member at a location that is between the switch magnet and the actuator magnet when the first and second members are in the initial relative orientation. The biasing magnet is oriented so that ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another when the first and second members are in the initial relative orientation. The biasing magnet and switch magnet housing may be positioned at a distance from one another. The distance may be 0.7 to 0.8 cm or preferably around 0.762 cm. The biasing magnet and the actuator magnet may be secured so that when the first and second members are in the initial relative orientation, the actuator magnet is 3.7 to 3.9 cm from the biasing magnet, and preferably about 3.81 cm. The biasing magnet may be positioned on the first member so that it extends along a shared axis with the actuator magnet when the first and second members are in the initial relative orientation.

[0050] Referring to step 808, detecting, via the alarm circuit, a position of the switch magnet. This step may include connecting the electrical leads to the alarm circuit, and detecting when the switch magnet simultaneously contacts both contacts of the switch magnet housing.

[0051] The method 800 may include additional, less, or alternate steps and / or device(s), including those discussed elsewhere herein. For example, the method 800 may include placing one or more magnetic ferrous shunts on surfaces of the housing facing away from the biasing magnet to magnetically isolate the switch magnet from magnetic fields other than the actuator magnet and biasing magnet.

[0052] Throughout this specification, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the current invention can include a variety of combinations and / or integrations of the embodiments described herein.

[0053] Although the present application sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this patent and equivalents. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical. Numerous alternative embodiments may be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.

[0054] As used herein, the phrase “and / or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing or excluding components A, B, and / or C, the composition can contain or exclude A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0055] The present description also uses numerical ranges to quantify certain parameters relating to various embodiments of the invention. It should be understood that when numerical ranges are provided, such ranges are to be construed as providing literal support for claim limitations that only recite the lower value of the range as well as claim limitations that only recite the upper value of the range. For example, a disclosed numerical range of about 10 to about 100 provides literal support for a claim reciting “greater than or equal to about 10” (with no upper bounds) and a claim reciting “less than or equal to about 100” (with no lower bounds).

[0056] Furthermore, unless otherwise specified, any directional references (e.g., upper, lower, above, below, etc.) are used herein solely for the sake of convenience and should beunderstood only in relation to each other. For instance, a component might in practice be oriented such that faces referred to as “upper” and “lower” are sideways, angled, inverted, etc. relative to the chosen frame of reference.

[0057] Throughout this specification, plural instances may implement components, operations, or structures described as a single instance. Although individual operations of one or more methods are illustrated and described as separate operations, one or more of the individual operations may be performed concurrently, and nothing requires that the operations be performed in the order illustrated. Structures and functionality presented as separate components in example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein.

[0058] As used herein, the terms “comprises.” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0059] The patent claims at the end of this patent application are not intended to be construed under 35 U.S.C. § 112(f) unless traditional means-plus-function language is expressly recited, such as “means for” or “step for” language being explicitly recited in the claim(s).

[0060] Although the technology has been described with reference to the embodiments illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the technology as recited in the claims.

[0061] Having thus described various embodiments of the technology, what is claimed as new and desired to be protected by Letters Patent includes the following:

Claims

CLAIMS1. A magnetic switch assembly for detecting relative movement between first and second members, the magnetic switch assembly comprising: a housing for mounting to the first member; a switch magnet housed in the housing and shiftable between a first position and a second position; a biasing magnet for mounting to the first member; and an actuator magnet for mounting to the second member and arranged so that when the first and second members are in an initial relative orientation, ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another, wherein the biasing magnet is selected and arranged so that the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position when the first and second members are in the initial relative orientation, and when the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position.

2. The magnetic switch assembly of claim 1, further comprising a circuit configured to detect when the switch magnet is in the first position.

3. The magnetic switch assembly of claim 2, wherein the housing comprises a pair of electrically conductive contacts in electrical communication with the circuit and operable to simultaneously contact the switch magnet when the switch magnet is in the first position.

4. The magnetic switch assembly of claim 1 , wherein the biasing magnet is selected and located so that when a defeat magnet is placed within a threshold distance to the switch magnet, the switch magnet shifts to the second position.

5. The magnetic switch assembly of claim 4, wherein the switch magnet has a magnetic flux density that is less than a magnetic flux density of the biasing magnet, and the biasing magnet has a magnetic flux density that is less than a magnetic flux density of the actuator magnet.

6. The magnetic switch assembly of claim 5. wherein the magnetic flux density of the switch magnet is 0.24 to 0.27 Tesla (T), the magnetic flux density of the biasing magnet is 0.435 to 0.465 T, and the magnetic flux density of the actuator magnet is 0.565 to 0.595 T.

7. The magnetic switch assembly of claim 4, wherein a distance between the biasing magnet and the switch magnet in the second position is 0.7 to 0.8 centimeters (cm), a distance between the biasing magnet and the actuator magnet when the first and second members are in the initial relative orientation is 3.7 to 3.9 cm, and the threshold distance is shorter than the distance between the biasing magnet and the actuator magnet when the first and second members are in the initial relative orientation.

8. The magnetic switch assembly of claim 1, wherein the switch magnet comprises at least one of neodymium or samarium cobalt.

9. The magnetic switch assembly of claim 8, wherein the switch magnet is spherically shaped.

10. The magnetic switch assembly of claim 1, wherein the switch magnet has a first magnetic pole and a second magnetic pole opposite to the first magnetic pole, the first magnetic pole is oriented in a first direction when the switch magnet is in the first position, and the first magnetic pole is oriented in a second direction that is different than the first direction when the switch magnet is in the second position.

11. The magnetic switch assembly of claim 10, wherein the first direction is opposite to the second direction.

12. A method of detecting relative movement between first and second members, the method comprising: securing a housing to the first member, the housing holding a switch magnet that is shiftable between first and second positions within the housing; securing an actuator magnet to the second member; securing a biasing magnet to the first member at a location that is between the switch magnet and the actuator magnet when the first and second members are in an initial relative orientation and oriented so that ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another, the biasing magnet is selected and arranged so that when the first and second members are in the initial relative orientation the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position, and when the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position; and detecting, via a circuit, a position of the switch magnet.

13. The method of claim 12, further comprising placing one or more magnetic ferrous shunts on surfaces of the housing facing away from the biasing magnet.

14. A magnetic switch assembly for detecting relative movement between first and second members, the magnetic switch assembly comprising: a housing for mounting to the first member; a switch magnet housed within the housing and having a first magnetic pole and a second magnetic pole, the switch magnet being shiftable between a first position within the housing in which the first magnetic pole is oriented in a first direction and a second position within the housing in which the first magnetic pole is oriented in a second direction that is different than the first direction; a biasing magnet for mounting to the first member and having first and second magnetic poles; and an actuator magnet for mounting to the second member and having first and second magnetic poles, the first magnetic pole of the actuator magnet having the same magnetic polarity as the first magnetic pole of the biasing magnet, the actuator magnet being selected and arranged so that when the first and second members are in an initial relative orientation, the first magnetic pole of the actuator magnet is proximal to the first magnetic pole of the biasing magnet and the second magnetic pole of the actuator magnet is distal to the first magnetic pole so that a magnetic field of the actuator magnet orients the first magnetic pole of the switch magnet in the second direction, and so that the second magnetic pole of the switch magnet is repelled by the second magnetic pole of the biasing magnet to shift the switch magnet to the first position, wherein the biasing magnet is selected and arranged so that when the first and second members are in a different relative orientation wherein the actuator magnet is remote from the switch magnet, the biasing magnet shifts the switch magnet to the second position.

15. The magnetic switch assembly of claim 14, wherein the biasing magnet is selected and located so that when a defeat magnet is placed within a threshold distance to the switch magnet, the switch magnet shifts to the second position.

16. The magnetic switch assembly of claim 15, wherein the switch magnet has a magnetic flux density that is less than a magnetic flux density of the biasing magnet, and the biasing magnet has a magnetic flux density that is less than a magnetic flux density of the actuator magnet.

17. The magnetic switch assembly of claim 16, wherein the magnetic flux density of the switch magnet is 0.24 to 0.27 Tesla (T), the magnetic flux density of the biasing magnet is 0.435 to 0.465 T, and the magnetic flux density of the actuator magnet is 0.565 to 0.595 T.

18. The magnetic switch assembly of claim 15, wherein a distance between the biasing magnet and the switch magnet in the second position is 0.7 to 0.8 centimeters (cm), a distance between the biasing magnet and the actuator magnet when the first and second members are in the initial relative orientation is 3.7 to 3.9 cm.

19. The magnetic switch assembly of claim 14, wherein the switch magnet comprises at least one of neodymium or samarium cobalt.

20. The magnetic switch assembly of claim 19, wherein the switch magnet is spherically shaped.21 . A magnetic switch assembly for detecting positions of a first member relative to a second member, the magnetic switch assembly comprising: a housing for mounting to the first member; a switch magnet housed in the housing and shiftable between a first position and a second position; a biasing magnet for mounting to the first member; and an actuator magnet for mounting to the second member and arranged so that when the first and second members are in a first relative orientation wherein the actuator magnet is within a first threshold distance but beyond a second threshold distance from the switch magnet, the ends of the actuator magnet and the biasing magnet having the same magnetic polarity are proximal to one another, wherein the biasing magnet is selected and arranged so that: when the first and second members are in the first relative orientation, the switch magnet is magnetically aligned with the actuator magnet and is repelled by the biasing magnet to shift the switch magnet to the first position, when the first and second members are in a second relative orientation wherein the actuator magnet is beyond the first threshold distance from the switch magnet, the biasing magnet shifts the switch magnet to the second position, and when the first and second members are in a third relative orientation wherein the actuator magnet is within the second threshold distance from the switch magnet, the actuator magnet shifts the switch magnet to the second position.

Images