Patent Application
20170263395
The present invention relates to switch cells and particularly relates to a switch cell apparatus having a non-electrical tactile feedback pad.
Automobiles represent a prime, but not an exclusive, example of the burgeoning market for electrical switches. A typical power seat in a modern automobile has multiple switches associated with it, e.g., one or more switch cells for adjusting forward/aft position, seat angle, lumbar support settings, etc. The tactile feel of the switches integrated into these switch cells represents a critical element of the “user experience.” Consequently, vehicle manufacturers, or the Original Equipment Manufacturers (OEMs) that supply them, often specify particular tactile curves for different switches, or for different switch functions, and for different switch applications, e.g., luxury or high-end applications versus economy or basic applications.
Switch cell manufacturers face significant challenges in controlling the number of switch designs needed to satisfy the varied and changing tactile feel requirements. Further complications arise in meeting the electrical requirements applicable to at least some types of switch cells. For example, so-called dome switches use a collapsible rubber dome or “pillow” as a movable switch contact, where the underside of the dome includes a carbon pad or other conductive material.
However, dome switches are, in general, not suitable for use in high current applications, such as where the switch cell will be used to switch current to the motors used for power seat adjustment. High-current switches commonly use “hard” switch contacts, i.e., sets of metallic contacts. While metallic switch contacts are well suited for switching the high currents associated with power seat motors, they tend to be loud and setting or controlling their tactile feel is challenging.
Embodiments of the present invention provide switch cells that use a non-electrical tactile feedback pad to adjust the tactile feel of the included switches. As a non-limiting advantage, separating the tactile feedback pad from the electrical switching operation allows the electrical contacts to be configured for high-current applications while relying on the tactile feedback pad to define or “tune” the tactile feel of the switch cell. Moreover, the same switch cell design may be used to meet a variety of tactile feel requirements, simply by installing different tactile feedback pads. That is, the same switch cell can be reconfigured to have a different tactile response curve simply by changing out the tactile feedback pad(s) used in the switch cell, without affecting the electrical characteristics of the switch cell.
According to some embodiments, a switch cell includes a housing assembly and a switch comprising first and second electrical contacts configured as a contact pair and supported within the housing assembly. The switch cell also includes a non-electrical tactile feedback pad separate from the switch and supported within the housing assembly. The tactile feedback pad has a configured compression force profile for imparting a desired tactile curve associated with actuation of the switch via an actuator assembly that is movably supported within the housing assembly. The actuator assembly comprises a first member extending to an exterior of the housing assembly and coupled to one or more interior members that are configured to actuate the switch while simultaneously compressing the tactile feedback pad when the first member is moved in a defined switch actuation direction.
Of course, the present invention is not limited to the above features and advantages. Those of ordinary skill in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
In the illustrated switch cell configuration, actuation of the switches 20 within the housing assembly 12 is accomplished via an actuator assembly 28 that is movably supported within the housing assembly 12. For example, the actuator assembly 28 may be configured as a joystick-like actuator that provides multi-axis actuation.
Here, the actuator assembly 28 comprises a first member 30 that extends to an exterior of the housing assembly 12 and is coupled to one or more interior members 32. The interior member(s) 32 are configured to actuate one or more of the switches 20 supported within the housing assembly 12 while simultaneously compressing the corresponding tactile feedback pad(s) 26 when the first member 30 is moved in a defined switch actuation direction. For example, if the first member 30 is moved or tilted towards the switch 20-1, the end 34-1 of a member 32-1 moves downward to actuate the switch 20-1 and, at the same time, the end 34-2 of the member 32-2 moves upward into compressive engagement with the tactile feedback pad 26-1. In other words, actuating the switch 20-1 compresses the tactile feedback pad 26-1. The same is true with respect to actuation of the switch 20-2 and the corresponding tactile feedback pad 26-2.
Consequently, while each switch 20 within the housing assembly 12 may contribute to a portion of the overall tactile feel experienced by a user when actuating the switch 20 via the actuator assembly 28, the overall tactile feel is established by the compression force profile of the tactile feedback pad 26 corresponding) the switch 20. That is, the tactile feedback pad 26 can be used to establish or tune the tactile feel, and a switch cell 10 that is otherwise the same as another switch cell 10 of the same design can exhibit markedly different tactile response curves simply by installing different tactile feedback pad(s) 26 in it.
Thus, in at least one embodiment, a switch cell 10 as contemplated herein includes first and second switches 20-1 and 20-2. Correspondingly, the one or more interior members of the switch actuation assembly 28 comprise opposing first and second actuator arms 32-1 and 32-2 that are configured to move in unison in opposing directions. According to the depicted configuration, moving the first member 30 in a first switch actuation direction causes the first actuator arm 32-1 to actuate the first switch 20-1 while simultaneously causing the second actuator arm 32-2 to compress a first non-electrical tactile feedback pad 26-1. Conversely, moving the first member 30 in an opposite, second switch actuation direction causes the second actuator arm 32-2 to actuate the second switch 20-2 while simultaneously causing the first actuator arm 32-1 to compress a second non-electrical tactile feedback pad 26-2.
Notably, the first and second electrical contacts 22, 24 of each switch 20 may be a pair of metallic contacts adapted for switching currents in excess of one Ampere. This feature makes the switch cell 10 well suited for high-current applications, which stands as an additional advantage on top of the advantageous ability to tailor the tactile feel of the switch cell 10 via tactile feedback pad(s) 26, which may be made removable or at least interchangeable between switch cells 10 of the same design.
In at least some embodiments, the one or more interior members 32 are configured in a rocker arm arrangement. The interior members 32 of the rocker arm arrangement include at least the first actuator arm 32-1 extending within the interior of the housing assembly 12 and an opposing second actuator arm 32-2 extending within the interior of the housing assembly 12. The first actuator arm 32-1 has a first end 34-1 positioned between a first switch 20-1 and a second non-electrical tactile feedback pad 26-2. The second actuator arm 32-2 has a second end 34-2 positioned between a second switch 20-2 and a first non-electrical tactile feedback pad 26-1.
Here, “between” can be understood as the rocker arm end 34-1 (or 34-2) having a tactile feedback pad 26-1 (or 26-2) above it and having an electrical contact 22 or 24 for the switch 20-1 (or 20-2) below it. Of course, the terms “above” and “below” are not intended to be limiting and are used merely to establish a convenient frame of reference with respect to the switch orientation seen in
One also sees that a member 44 formed here as a disk includes or carries a number of tactile feedback pads 26, e.g., one tactile feedback pad 26 for each switch 20 included in the switch cell 10. The four switches 20 implemented in this embodiment are formed using a common normally-closed terminal 46, a set of four movable springs 48, a set of four movable arms 50 with contact pills, a set of four hooks 52, and a set of four contact terminals 54.
The member 44 comprises, for example, a disk made of elastomeric or other resilient material. In one such embodiment, each tactile feedback pad 26 comprises a collapsible dome formed within the resilient member 44. In another embodiment, each tactile feedback pad 26 comprises a thickened section of the member 44. The tactile feedback pad 26 thus operates as a soft stop for limiting the travel of the actuator assembly 28.
Implementing the tactile feedback pads 26 via the member 44 allows a switch cell manufacturer to build or reconfigure a given switch cell 10 with a particular tactile feedback response, or with a particular set of tactile feedback responses for multiple included switches 20, simply by selecting or changing the member 44. The same switch cell 10 can be imbued with different tactile feedback responses merely by selecting the appropriate member 44. Moreover, it should be understood that in cases where the member 44 carries more than one tactile feedback pad 26, two or more of those tactile feedback pads 26 may have different compression force profiles i.e., they may provide different tactile feel response curves.
Still further, any one or more of the tactile feedback pads 26 carried by the member 44 may have a “snap” actuation or a non-snap actuation, where a snap actuation has a markedly non-linear compression force profile that results in higher initial resistance, followed by sharp or step-change lowering of resistance as the tactile feedback pad 26 is compressed beyond a certain point or amount. In this regard, the tactile feedback pads 26 can be formed as domes or pillows in the member 44, or merely as thickened areas of the member 44, or the entire member 44 may be formed such that it has a broad, possibly continuous area or region where any point is suitable for use as a tactile feedback pad 26.
Regardless of the particulars by which the tactile feedback pad(s) 26 are implemented in the member 44, in one or more embodiments the member 44 is configured to isolate a lower interior portion of the housing assembly 12, when it is installed within the housing assembly 12. The member 44 thereby provides at least one of sound isolation and water resistance for the switch(es) 20 positioned within the lower interior portion of the housing assembly 12. Thus, as a further advantage in some embodiments, the member 44 not only serves as a carrier for the tactile feedback pad(s) 26, it reduces switching sounds and provides fluid and/or contamination resistance for the switches) 20. Correspondingly, in at least some embodiments, the switch cell 10 is configured such that the tactile feedback pad 26 is installable in and removable from the housing assembly 12 independent of the switch(es) 20.
The overall tactile curve exhibited by a switch 20 in the switch cell 10 can be understood as the sum of two tactile curves: the tactile curve of each of the switch 20, and the tactile curve of the corresponding tactile feedback pad 20. The curve associated with tactile feedback pad 26 may, however, be dominant.
Note that in this example, the 0.75 mm mark represents the point of contact closure for the switch 20, and the 1.50 mm mark represents the hard stop limit of the switch 20. One sees that the tactile response curve of the tactile feedback pad 26 dramatically softens or otherwise masks the hard stop exhibited by the bare switch 20. In other words, one of the several advantages gained by use of the tactile feedback pad 26 is that it imparts a “soft stop” characteristic to the overall switch cell 10, as the user encounters the travel limit of the switch 20.
Further, the actuator knobs or appendages that are typically fastened to the first member 30 of the switch actuator assembly 28 in a finished installation may be asymmetrical and may include shapes other than squares, cylinders or spheres, Accordingly, the tactile feedback pad 26 may be designed with different tactile curves corresponding to different actuator movement directions, in order to balance the feel experienced by the user for the different actuation directions, or to impart distinctively different tactile feel to different actuation directions and/or different adjustment functions.
Notably, modifications and other embodiments of the disclosed inventions) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. For example, a sliding rather than a rocking actuator may be used in the switch cell 10, with the sliding actuator sliding into engagement with one or more tactile feedback pads 26 when a switch 20 is actuated.
Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
