Patent Application
20140311818
One aspect of the invention relates to audio speaker grilles and covers. Another relates to methods for mounting a speaker grille to an underlying panel or surface such as found in a vehicle or wall in which a speaker opening is formed.
Audio equipment generates sound that is transmitted to a listener from its source through intervening media. Such media include speaker grilles and covers (interchangeably referred to herein as “grilles” or “covers”) that are engineered for protection, ease of installation, visual appearance and sound transmissivity without sacrificing fidelity. Often, added protection is achieved at the expense of sound quality.
Conventional grille covers have been made in plastic. They are detachably mounted on or secured to a substrate panel or frame through tabs or other spring and hook attachment methods. Attachment methods that become weakened in use over time can lead to unfavorable buzzing noises, squeaks or rattles that interfere with acoustic properties.
Some grilles are made from expanded metal. Expanded metal patterns are traditionally created by saw tooth blades. These blades typically have a repeating unit of length referred to as the LWD (long way diamond) whose angles and flat dimensions are defined to create a pattern with desired characteristics. These blades expand the metal by taking an indexed amount of material called the strand width (SW) and subsequently shearing and stretching material over a lower striker bar until it conforms to the shape of the blade. When the blade is square to the striker bar and SW is constant, a uniform pattern is created which most would identify as standard expanded metal whose appearance is uniform over the entire surface.
Before filing this application, the following U.S. Patents were considered: Nos. 5,652,413; 5,565,659; and 4,974,698.
One aspect of the disclosure comprehends a grille for covering an aperture in a panel that supports audio equipment attached to a back face of the panel, the grille being installed upon a front face of the panel. The grille comprises a formed sheet of pierced and expanded sheet material that has a major axis (A-A) running parallel to a direction in which the sheet is introduced to a forming machine and a minor axis (B-B) that extends orthogonally to the major axis (A-A). The formed sheet has a central generally planar or domed portion with surface discontinuities selected from the group consisting of swirls, stiffening furrows and ridges running substantially parallel to the major axis (A-A) and combinations thereof
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
As exemplified in
One aspect of several embodiments of the disclosed product is that the grilles are relatively stiff in one direction (e.g., A-A), yet compliant in another (“anisotropic”) (e.g., B-B). Most embodiments are longer in one direction than in another direction. As a frame of reference, a major axis (A-A) (
Skips 18 are created in a forming step perpendicularly to the direction in which feed stock is introduced to a forming machine. In general the skips 18 are oriented parallel to the minor axis. One row is shown in
If present, the ridge lines 20 (
Depending on the parameters of machining, localized surface discontinuities in speaker grilles can be created by material discontinuities that are referred to herein as “skips” 18. Such features are created by momentarily interrupting the feed rate of stock as it passes through or under a perforation tool that penetrates at a relatively constant rate or by altering the periodicity with which the tool perforates stock that is introduced to the tool at a relatively uniform feed rate.
Such skips 18 typically lie along a linear path and extend over the entire width of the feed stock as shown in
The skips 18 alter the visual appearance of the grille, which takes on different hues or appearances depending on the vantage point of the observer and the light that is incident on the grille 10. They thus enhance the appearance of the grille without reducing its ability to allow sound to pass there through with minimal distortion.
In some embodiments, the skips lie in an arcuate path 24. This effect is produced by altering the feed rate across the width of the feed stock. For example, a feed rate along one edge of the stock may be (X) cm/sec, but the feed rate along the opposite edge may be (X±ΔX) cm/sec. This creates a visually attractive swirl appearance, in which adjacent cells 18 in the expanded material trace an arcuate or curvilinear path. This effect can be prepared not only by changing the feed rate across the width of incoming feed stock in order to create different patterns, but also by altering the impact timing of multiple teeth along a row of teeth in a tool as they penetrate feed stock that passes at a uniform throughput rate.
Alternatively, unit cell size of a skip can be varied from one edge to another edge across a given roll or width of feed stock. This is enabled by providing punching tools with teeth or punches of different dimensions across the width of the metal stock. Thus, it is possible to prepare a sheet of expanded metal having edges in which the hole spacing adjacent to one edge is more densely packed than hole spacing at the opposite edge.
For analysis, a given skip can be considered as a unit cell having for example four edges that are defined by strands of material which are connected at their ends to form in one example a quadrilateral cell with edges a-b, b-c, c-d and d-a. It will be appreciated that the invention is not so limited. Some cells may have two edges (slits or slots), three edges or more than four edges. Further, the unit cell 18 may not emerge from the tool as planar. For instance the edge a-b may have a different inclination to a reference plane than one or more of the other edges. Similarly for the sizes of edges in a given cell.
In addition to skips, ribs 20 can optionally be prepared that extend generally parallel to a major axis (A-A) of the speaker grille cover. If present, the ribs can be separated by furrows or valleys 22. The ribs strengthen the grille cover's resistance to bending forces applied along their length. In this sense, the grille becomes anisotropic. Not only do such features influence the structural characteristics of the formed grille but also they influence its visual characteristics without significant detrimental effect on acoustic properties.
Skips and/or ribs or skips alone may also extend to the underlying attachment tabs 14 (
In one embodiment, the speaker grille 10 of the present invention is manufactured from a sheet of mild steel or plastic. The sheet is passed through a forming tool (
As mentioned earlier, expanded metal patterns are traditionally created by saw tooth blades. These blades typically have a repeating unit of length referred to as the LWD (long way diamond) whose angles and flat dimensions are defined to create a pattern with desired characteristics. These blades expand the metal by taking an indexed amount of material called the strand width (SW) and subsequently shearing and stretching material over a lower striker bar until it conforms to the shape of the blade. When the blade is square to the striker bar and SW is constant, a uniform pattern is created which most would identify as standard expanded metal whose appearance is uniform over the entire surface.
One aspect of this disclosure incorporates a fade pattern. It was found that a variety of looks could be created maintaining the blade square to the striker bar but varying the SW in a pattern that may or may not repeat. A nearly infinite sequence of SW changes can be programmed into the feed system which changes the amount of material that is metered out per unit expansion. This results in areas of variable density in the feed (SW) direction. These areas of variable density create an appearance that is different from traditional expanded metal.
Another aspect of this disclosure includes a fan pattern. A fan pattern is created by setting the blade at an angle relative to the striker bar. For a constant strand width pattern, one side of the material will expand at a faster rate relative to the other. The expanded material appears to “fan” out from the expansion tool.
Combinations of the above are also anticipated.
One attribute of the speaker grille covers that are manufactured following the disclosed practices is that they have a visual appeal without sacrificing acoustic properties. When exposed to light they have alternating translucency and opacity depending on their orientation to illumination or the vantage point of the observer. Several embodiments create a unique appearance by changing the plane of formation and/or density of apertures or cells per unit dimension (e.g. per square inch).
Thus an otherwise bland structural grille can be transformed into a visually appealing yet functional object that allows sound to pass there through without sacrificing acoustic quality.
In one embodiment, there are two stages of attachment: 1) deflection of an attachment feature, such as a holding tab 14; and 2) after the deflected tab 14 is lowered into an aperture defined in the supporting panel 16, snapping the tab into place on an undersurface 26 of the panel. The attachment features include optional locking mechanisms and optional gripping mechanisms.
During the manufacturing step it is thought that some work hardening occurs at ambient temperatures in the edge 12 and tabs 14 that extend therefrom that are respectively turned downwardly and deflected backwardly from the plane of the grille. Additionally (
By practicing the techniques disclosed herein, it is possible to create speaker grille covers 10 that not only offer an enhanced visual appearance, but have audio characteristics that are substantially unchanged by the visual enhancements enabled by skips or swirls caused by changes in the spacing between or relative orientation of adjacent cells in the expanded metal. The inventors have found that high-frequency sound and bass tones are transmitted with good fidelity.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
