Electrical measurement instruments, such as digital multimeters (DMMs), can often be configured to measure a variety of electrical parameters, such as voltage, current, and resistance. Many DMMs are able to switch between various sets of inputs, with each set of inputs or channels supporting most measurement functions of the DMM. Electrical measurement instruments, therefore, typically include an electrical switch for selecting between the various channels.
In some electrical measurement instruments, an external switch may be installed onto a printed circuit board (PCB) for selecting between channels. In other instruments a PCB of the electrical measurement instrument may be configured to form a switch. In general, such a PCB switch comprises a plurality of contacts on a surface of the PCB and one or more conductive springs configured to make electrical contact with one of the respective plurality of contacts when pressed there against. In order to place the electrical measurement instrument in a first state, at least one of the conductive springs is compressed against a first contact formed on the PCB. In order to place the electrical measurement instrument in a second state, the conductive spring is translated to a second position, which for example, presses the conductive spring in contact with a second contact. As the conductive spring moves across the PCB from the first contact to the second contact, the free end of the conductive spring scrapes along the surface of the first and second contacts as well as the PCB. Thus, in such switches, switching from one state to another state may cause wear to the conductive springs therein due to frictional forces applied to the conductive springs. The wear caused to the end of the conductive spring may also potentially damage the contacts and the PCB.
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 of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In accordance with aspects of the present disclosure, a switch assembly is provided. The switch assembly may include a substrate, a sliding plate, at least one conductive component, and an insulative body. The substrate may have at least one first conductive contact. The slide plate may be secured to the substrate and have a contoured surface. The at least one conductive component may be configured to electrically connect with the at least one first conductive contact when the at least one conductive component is in a first position. The insulative body may be configured to hold the at least one conductive component. The insulative body may be moveable along the contoured surface of the slide plate and configured to move the at least one conductive component from the first position to a second position. When the first conductive contact is in the second position, the conductive component is a distance away from the first conductive contact.
In accordance with aspects of the present disclosure, a switch assembly comprising a printed circuit board, a first conductive contact, and an insulative body is provided. The printed circuit board may include at least one slot. The at least one slot may have a first end and a second end. The first conductive contact may be provided at the first end of the at least one slot. The insulative body may include at least one conductive member that is configured to be positioned within the at least one slot and may be moveable within the at least one slot to selectively contact the first conductive contact.
In accordance with aspects of the present disclosure, a method of switching an electrical device from a first state to a second state is provided. The method may include compressing at least one conductive spring on a first respective conductive contact to place the electrical device in the first state. The conductive spring may being held by an insulative body. The method may further include sliding a portion of the insulative body along a contoured surface to move the at least one conductive spring from the first respective conductive contact to a second respective conductive contact. Sliding the portion of the insulative body along the contoured surface may reduce an amount at which the at least one conductive spring is compressed. The method may further include compressing the at least one conductive spring on the second respective conductive contact to place the electrical device in the second state.
In accordance with aspects of the present disclosure, a method of switching an electrical device from a first state to a second state may include moving a conductive member of the electrical device to a first position. The conductive member may be positioned in a slot formed in the printed circuit board. When the conductive member is in the first position, the conductive member electrically couples to a first conductive contact formed at a first end of the slot placing the electrical device in the first state. The method may further include moving the conductive member from the first position away from the first conductor contact to a second position placing the electrical device in the second state.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
While illustrative embodiments are illustrated and described below, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. In that regard, the detailed description set forth below, in connection with the appended drawings where like numerals reference like elements, is intended only as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Accordingly, various changes can be made therein without departing from the spirit and scope of the disclosure. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result.
The following discussion provides examples of one or more switch assemblies and methods of using the same. Generally described, one or more embodiments of the present disclosure are directed to switch assemblies and methods for switching a switch assembly from one state to another, such as switching from a closed state to an open state and/or vice versa. In some examples, a switch assembly may be configured to switch from one state to another by moving a conductive component, such as such as a spring, bar, member, etc., from a first conductive contact located on a substrate, such as a printed circuit board (PCB), to a second conductive contact located on the substrate. As will be described in more detail below, embodiments of the present disclosure may be configured to reduce wear on the switch assemblies' conductive components, including the conductive component and conductive contacts, as well as associated components of the switch, when moving the conductive component (i.e., switching) from the first conductive contact to the second conductive contact. For instance, in one embodiment, the conductive component, such as a spring, member, rod, bar, etc., moves within a slot in the PCB, thereby eliminating contact between the conductive component and the surface of the PCB. In another embodiment, friction forces and/or other forces applied to the conductive component and/or the PCB are reduced as the conductive component moves across the PCB surface from a first conductive contact to a second conductive contact.
Although the switch assemblies may be shown and described in reference to electrical measurement instruments, it should be appreciated that the methods and assemblies described herein may be used in any electrical device or the like requiring the use of an electrical switch. Furthermore, although the examples illustrated herein are directed to double throw switches, it is to be appreciated that the switch assemblies may apply to any number of throws, including a single throw switch. In examples of single throw switches, the switch assembly may be in a closed state when a conductive spring is in contact with the single conductive contact allowing current to flow therethrough, or in an open state when the conductive spring is separate from the single conductive contact preventing current from flowing therethrough. It will be further appreciated that the electrical switches described herein apply to any number of poles.
Turning now to
As best shown in
Referring to
The switch assembly 100 further includes a slide plate 104 having first and second surfaces 122 and 124, as best shown in FIGS. 2 and 3A-3C. In the embodiment shown, the second surface 124 of the slide plate 104 interfaces with and may be secured to the second surface 114 of the PCB 102. The first surface 122 of the slide plate 104, on the other hand, may include one or more contours 128, the purpose of which will be described later in more detail.
As briefly described above, the switch body 106 is movable between a first position, such as the position illustrated in
Returning now to
Each of the conductive springs 136 are positioned within the switch body 106 in a manner that allows the conductive springs 136 to be placed in electrical communication or electrical connection with two adjacent conductive contacts 118 when the switch body 106 is moved to the first or second position. For instance, the second end 140 of each conductive spring 136 may be configured to contact a first respective conductive contact 118 when the switch body 106 is in a first position, such as the position in
The switch body 106 may further include one or more insulative members 144. The insulative members 144 may be positioned between each adjacent conductive spring 136 so as to assist in electrically isolating each conductive spring 136. The insulative members 144 may be formed integral with the switch body 106 as illustrated in
Returning now to
As assembled, the retaining arms 108 hold the switch body 106 on or adjacent the first surface 112 of the PCB 102, while still allowing the switch body 106 to move along the first surface 112 of the PCB 102 between first and second positions. Additionally, the retaining arms 108 are capable of applying a suitable force to slide plate 104 to counteract the biasing force applied to the PCB 102 via the conductive springs 136. In the embodiment shown, the lip 148 of the retaining arms 108 may be configured to slide along the first surface 122 of the slide plate 120. In that regard, each lip 148 of the retaining arms 108 may be configured to slide along a corresponding contour 128 when the switch assembly 100 is moved from a first position to a second position. As each lip 148 slides along a corresponding contour 128, the amount of force applied by the conductive springs 136 on the first surface 112 of the PCB 102 is reduced in relation to the geometry of the contour. This reduction in force applied to the switch body 104 corresponds to a reduction in the amount each conductive spring 136 is compressed.
An example of an operation of switching the switch assembly 100 from a first position as illustrated in
As the switch body 106 moves from the first position to the second position, the lip 148 of the retaining arms 108 slides along the contours 128 of the sliding plate 104 as illustrated by the intermediate position in
From the description set forth above, it should be appreciated that as the second end 140 of a conductive spring 136 slides along the first surface 112 of the PCB 102, including along a portion of the conductive contacts 118, the resulting force being applied to the second end 140 is also reduced as the contour 128 path is followed. In that regard, frictional and/or other forces applied to the second end 140 of the conductive spring 136 are also reduced. In some embodiments, this may reduce wear to the second end 140 of the conductive spring 136. Similarly, the frictional and/or other forces applied to the PCB 102 and/or the conductive contacts 118 may be reduced. In some embodiments, this may reduce wear and/or damage incurred by the PCB 102 and/or the conductive contact 118.
When the switch body 106 reaches the second position as illustrated by
In an alternative embodiment, the slide plate 104 may be secured to the first surface 112 of the PCB 102. In this alternative embodiment, the slide plate 104 may be provided between the switch body 106 and the PCB 102. In particular, the second surface 124 of the slide plate 104 may be secured to the first surface 112 of the PCB 102, and the inner surface 134 of the switch body 106 may be on or adjacent the first surface 122 of the slide plate 104. In this embodiment, the switch body 106 may be configured to slide along the first surface 122 of the sliding plate 104. However, it will be appreciated that the contours on the first surface 122 of the slide plate 104 may be convex. As such, the convex contour portions reduce the forces applied to the PCB 102 and each conductive spring 136.
In other alternative embodiments, a cam or pivot arm may be utilized to reduce an amount of force applied to the PCB 102 by the conductive springs. That is, the cam or pivot arm may be coupled to the switch body 106 causing the switch body 106 to move away from the first surface 112 of the PCB 102 thereby reducing the amount of force being applied to the surface thereof by the conductive springs 136. In yet another alternative embodiment, the contour 128 on the slide plate 104 may be integral with the first surface 112 or the second surface 114 of the PCB 102.
Turning now to
As best shown in
The switch assembly 200 further includes pairs of conductive contacts 218, each pair being associated with an opening 272. In the embodiment shown, respective conductive contacts 218 may be formed at each end of the openings 272. That is, a conductive contact 218 may be formed at the first end 274 of each opening 272, and a conductive contact 218 may be formed at the second end 276 of each opening 272. The conductive contacts 218 may be constructed of any material or materials configured to allow electrons to flow therethrough. It will be appreciated that the conductive contacts 218 may be in electrical connection with other components (not shown) on the PCB 202 via traces (not shown) formed within the PCB 202. In one embodiment, the conductive contacts 218 are made of copper and plated with a noble metal, such as gold. In some embodiments, one or more edges of the conductive contacts 218 may be beveled.
Still referring to
In embodiments of the present disclosure, the one or more conductive members 236 may be any conductive member configured to electrically connect with a corresponding conductive contact 218 when a portion of the conductive member 236 abuts the conductive contact 218. In one embodiment, the conductive members 236 may be a spring. Non-limiting examples of the conductive members 236 may include a leaf spring, a C-shaped spring, a coil spring, or any spring or member configured to make suitable electrical contact with the conductive contacts 218. In other embodiments, the conductive members are bars, rods, etc. In one embodiment, the conductive members 236 are copper conductive members, which may or may not be plated with a noble metal, such as gold.
When assembled, as illustrated in
In some embodiments of the present disclosure, the switch body 206 may be manually actuated between first and second positions. In other embodiments, an actuator, such as actuator 130 as described in reference to
Similarly, as the actuator 130 causes the switch body 206 to move to a second position, i.e. towards the conductive contacts 218 located at the second end 276 of the opening 272, the conductive members 236 move within the corresponding openings 272 until the conductive members 236 make physical contact with the conductive contacts 218 at the second end 276 of the opening 272. When the switch assembly 200 is in the second position and a portion of each conductive member 236 is in electrical connection with a corresponding conductive contact 218, the switch assembly 200 is placed in a second state. As will be clear to those skilled in the art, the illustrated switch assembly 200 may be modified for any number of poles. In that regard, any number of slots and any number of conductive contacts may be employed based on the intended purpose of the switch assembly.
Various principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the claimed subject matter.
Number | Name | Date | Kind |
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4057520 | Schwartz | Nov 1977 | A |
4871885 | Kamada | Oct 1989 | A |
4975547 | Nakayama et al. | Dec 1990 | A |
6841749 | Radosavljevic et al. | Jan 2005 | B1 |
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Number | Date | Country |
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WO 2009116364 | Sep 2009 | WO |
Entry |
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European Search Report mailed Nov. 21, 2012, issued in European Application No. 11178130.8, filed Aug. 19, 2011. |
Number | Date | Country | |
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20120217146 A1 | Aug 2012 | US |