Patent Application
20100066026
This invention relates to mechanical seals, and more particularly, to sympathetic seals used in electronic devices.
Seals used to protect components used in portable electronic devices are commonly used in order to protect an inner portion of the device from water, moisture and other outside elements. One type of seal most often used in these devices is a compression-type seal. Compression seals are probably the oldest and most common seal type where sealing is accomplished by tightening the seal along its edge such that it is compressed onto another mating surface. Compression seals, or gland seals, are used in such applications as compression packing, gaskets, and fluid sealing type devices. Compression packing seals often work to seal any number of fluids, including water, acids, solvents, gases, oil, and other chemicals, in a range of varying conditions, such as temperature and pressure. Thus, compression seals are a broad category that is manufactured in a wide array of shapes, sizes, and constructions using many different types of materials.
Prior art
Still another type of seal commonly used in the prior art is “lip” seal. A lip seal comprises a flexible lip that rubs against an edge in a housing to prevent the leakage or ingress of both fluids and dirt. For proper installation, the seal lip typically points toward the medium being contained. Thus, the sealing orientation and direction is an important consideration depending on the type of application. The orientation and direction can be internal, external, symmetric, or axial. As with the compression seal, the lip seal may be press-fit into a housing bore with the sealing lip contacting another surface such that the lip seal may seal axially against a housing or machine component.
Prior art
Thus, before selecting either a compression or lip seal, it is important to understand a number of specific parameters that can affect performance, such as the size of the cross section that is to be sealed, the media and its specific qualities, the type of electronic equipment, and the temperature and pressure of the media being sealed. Once these variables have been determined, the proper seal can be selected.
As will be appreciated by those skilled in the art, drawbacks for the standard compression type seal as seen in
The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to a sympathetic seal system for use in an electronic device. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.
Thus, an important aspect of the invention is that the compression surface 511 is angled outwardly with respect the direction of seal compression such that the compression surface 511 biases a sympathetic seal 525 (described hereinafter). When in compression, the sympathetic seal 525 moves in an outward manner from the interior of the internal cavity when the lower housing 501 and upper housing 516 are mated. Hence, an angular notch 510 that is formed at the intersection of the angular wall 509 and the compression surface 511 operate to bias the sympathetic seal into a substantially fixed position. A lateral wall 513 extends from the compression surface 511 toward the outside wall 503 such that an inner wall 515 is formed extending from the lateral wall 513.
Similarly, the upper housing 516 includes an inner mating surface 517 which substantially abuts the outer mating surface 507 when in an assembled state. The sidewall 521 is substantially orthogonal to the inner mating surface 517 where an outside wall 523 also extends orthogonally from the sidewall 521 forming an outer face of the upper housing 516. In order to form a watertight seal between the lower housing 501 and upper housing 516, the upper housing 516 comprises a sympathetic seal 525 which is overmolded around the perimeter of the upper housing 516. When not in compression, the sympathetic seal 525 has a substantially truncated conical shape in cross section that comprises a wide end 527 that is joined with the inner mating surface 517 and a truncated end 529. The truncated end 529 is used to mate within the angular notch 510.
As described herein, the seal 525 is manufactured of silicone or like material and is generally referred to as “sympathetic” in view of its existence and operation through an affinity, interdependence, or mutual association with various biasing components in the lower housing 501. In other words, the sympathetic seal 525 operates as a system in combination with the angular wall 509 and compression surface 511 used in the lower housing 510 for enabling the seal to operate more effectively as inward submersion pressure is increased. Hence, as the high pressure or “fluid” side of the sympathetic seal 25 is increased this acts to simultaneously increase the seal loading forces against the sealing surfaces, such as compression surface 511. Although some lip seals can operate in a similar “sympathetic” manner, the present invention is advantageous since it can be accomplished with much less tooling and overall complexity.
In order to provide a watertight seal and prevent water or other fluids from entering the cavity 618 when subjected to submersion pressures, the sympathetic seal 605 is positioned within the angular notch 611. This acts to deform lower edge 607 and side edge 609 of the sympathetic seal 605. The sympathetic seal 605 deforms in a manner in order to prevent water or other fluids from extending substantially beyond the angular notch 611. This occurs in view of the substantially tight seal made between lower edge 607 and the compression surface 613 as well as between the side edge 609 and the angular wall 615. As seen in
Further, the invention may also comprise a plastic outer skin 619 which covers the lower housing 601 and upper housing 603. The plastic outer skin 619 is a “sealed alloy endoskeleton” concept such that the lower housing 601 and upper housing 603 are castings that are encased in a skin 619 manufactured from durable plastic or other synthetic materials that does not form a seal per se but rather serves to protect the casting structures from vibration and shock. The plastic skin 619 also comprises ergonomic advantages to the electric equipment such as a two-way portable transceiver, such that it provides improved hold, grip and overall controllability when operating the device.
Although specific embodiments of the present invention have been described, those of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.
