WO2012052871A1

WO2012052871A1 - A waterproof device

Info

Publication number: WO2012052871A1
Application number: PCT/IB2011/054444
Authority: WO
Inventors: Xiang Wang; Martin Mason
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-10-18
Filing date: 2011-10-10
Publication date: 2012-04-26

Abstract

This invention provides a device comprising a housing with an opening at its corner, defined by a first and a second sidewall and a top wall, the first sidewall comprising a first slope; a lid to seal the opening, comprising a first, a second, a third and a fourth edge, the first edge comprising a second slope corresponding to the first slope, and the third edge comprising a first tab; a fastening means to fasten the housing and the lid to one another; and a sealing layer to seal the housing and the lid. When the lid is fitted to the housing, retaining forces along 3 orthogonal directions are generated simultaneously.

Description

A WATERPROOF DEVICE

Technical field

The invention relates to a waterproof device, and particularly to a device with a sealing configuration.

Background of the invention

Waterproofness is a requirement for many devices. For example, appliances intended to be used in or likely to be exposed to wet environments, are waterproof sealed to protect the electrical components within. In most cases the profile to be sealed is generally two- dimensional. As shown in FIG. 1 , the device 100 comprises two profiles 1 10 and 120 to be sealed, wherein the profile 1 10 lies within one plane and the profile 120 lies in two intersecting planes intersecting at a small angle. In these circumstances, a press force along the normal direction of the main plane, the direction D in FIG. 1 for example, will suffice for sealing.

Walters discloses, in U.S. Pat. Pub. No. 2007/0139915, a casing for a portable device having a case that defines an internal compartment, a cover for covering the compartment opening and a layer that is overmolded over the case, in which the overmolded layer seals the opening in conjunction with the cover.

However, in many cases, the profile to be sealed is preferably situated on a corner of a device due to space or structure limitations. For example, for a handheld battery-powered medical device 200 as shown in figure 2, the battery 250 is too big to be placed along the X direction. If the battery 250 is placed at locations other than the corner, the printed circuit boards (PCB) 260 inside need to be cut to an odd shape to make room for the battery 250, and this will add to the difficulty in terms of the PCB layout. The same problems are encountered in many other electrical devices.

Summary of the invention It would therefore be desirable to achieve a waterproof device providing retaining forces acting simultaneously along 3 orthogonal directions to seal an opening with a three- dimensional profile. It would also be advantageous to achieve a waterproof device having a sealing component on a corner thereof so that the internal space of the device is utilized efficiently.

To better address one or more of these concerns, in one embodiment of the present invention, there is provided a device comprising:

a housing having an opening at a corner thereof, the opening being defined by a first and a second sidewall and a top wall, the first sidewall comprising a first slope;

a lid, intended to be fitted to the housing to seal the opening, the lid comprising a first, a second, a third and a fourth edge, the first edge comprising a second slope corresponding to the first slope, and the third edge comprising a first tab;

a fastening means, configured to fasten the housing and the lid to one another; and a sealing layer, configured to seal the housing and the lid, the sealing layer being made of a soft material relative to the material of the housing and the lid,

wherein, when the lid is fitted to the housing by pushing it along a first direction, the first and second slopes are in engagement with one another to generate a first retaining force along a second direction perpendicular to the first direction, the first tab is inserted beneath the top wall to generate a second retaining force along a third direction perpendicular to the first and the second direction, and the fastening means generate a third retaining force along the first direction and a fourth retaining force along the third direction.

The basic idea is to generate retaining forces acting simultaneously along 3 orthogonal directions during and after fitting the lid to the housing. By cooperation between the inclined surfaces of the lid and the housing, and by cooperation between the first tab and the top wall, and the fastening means, the sealing layer between the complete periphery of the opening and the complete periphery of the lid is deformed, resulting in a three-dimensional sealing.

In another embodiment of the present invention, the sealing layer is molded over the periphery of one of the lid and the opening so that the sealing layer is secured to one of the lid and the opening, and the possibility of sealing failure caused by misalignment of the sealing layer between the housing and the lid is eliminated.

In another embodiment of the present invention, the fastening means comprises a first portion in the second sidewall of the housing and a second portion at the third end of the lid. In one example, the first portion is a screw hole and the second portion is a through hole permitting a screw to be passed through and to be subsequently driven into the screw hole. In one example, the screw hole and the through hole are positioned in an inclined direction relative to a normal of the top wall so that the third sealing force and the fourth sealing force are generated simultaneously between the screw hole and a rod of the screw.

In another embodiment of the present invention, the sealing layer further comprises an extension portion configured to plug and seal the through hole after the screw is driven into the screw hole, so that penetration of water through any seam between the screw hole and the screw is prevented. Furthermore, the extension portion exerts a press force on the screw, resulting from friction between a peripheral surface of the extension portion and an inner surface of the through hole, thereby preventing the screw from loosening.

These and other features, aspects, and advantages of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief description of the drawings

The above and other objects, characteristics and merits of the present invention will become more apparent from the following detailed description considered in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a device having a profile to be sealed substantially in one plane;

Fig. 2 is a perspective view of a device to be sealed in the corner;

Fig. 3 is a perspective view of a waterproof device according to one embodiment of the invention;

Fig. 4a is a perspective view of the embodiment of Fig. 3 illustrating the lid 320 being fitted to the housing 310;

Fig. 4b is a top view of the embodiment of Fig. 3 illustrating the lid 320 fitted to the housing 310;

Fig. 4c is a sectional view taken along line A-A of Fig. 4b;

Fig. 5 is a perspective view of a waterproof device according to another embodiment of the invention;

Fig. 6 is a perspective view of a waterproof device according to another embodiment of the invention,

wherein same or analogous reference numerals are used to represent same or analogous features/devices (modules) throughout the figures.

Detailed description of the embodiments

Reference will now be made to embodiments of the invention, one or more examples of which are illustrated in the figures. The embodiments are provided by way of explanation of the invention, and are not to be construed as a limitation of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield a still further embodiment. It is intended that the present invention encompasses these and other modifications and variations as come within the scope and spirit of the invention.

Fig. 3 illustrates an exemplary device 300 according to one embodiment of the invention. The device 300 includes a housing 310 configured for accommodating functional components, such as the printed circuit boards 260 as shown in Fig. 2, for example. The housing 310 includes an opening 314 allowing access to the interior of the device 300, for example, for the purpose of changing the components inside. For example, when the device 300 is a handset device, the opening 314 permits access to a battery compartment of the device 300 where batteries are received. And the opening 314 is arranged at a corner of the housing 310, for the benefit of a convenient PCB layout, for example. The device 300 also includes a lid 320 that is intended to be fitted to the housing 310 to cover the opening 314 so that the components within the device 300 are covered and protected, as will be described in greater detail later. The device 300 further includes a fastening means 330 configured to fasten the housing 310 and the lid 320 to one another once the lid 320 is fitted to the housing 310, and a sealing layer 340 configured to form a seal between the housing 310 and the lid 320. As discussed, the device 300 is well suited for applications where sealing at a corner of a device is desired. It should be appreciated, however, that a device 300 in accordance with one embodiment of the invention is not limited to the use according to said embodiment. The housing 310 is made of any suitable material known in the art of encapsulation applications. And the housing 310 may take on various configurations, but generally includes four sidewalls, a top wall and a bottom wall. Still referring to Fig. 3, the opening 314 of the housing 310 is defined through a first sidewall 31 1 , a second sidewall 312 and a top wall 313 of the housing 310. The first sidewall 31 1 includes at least one inwardly extending first slope

315 to generate a first retaining force which retains the sealing in a direction substantially perpendicular to the first sidewall 31 1 , as will be described in detail later. In the embodiment illustrated in Fig. 3, the first sidewall 311 includes two first slopes 315. However, one or more than two first slopes may also be provided. For example, the first sidewall 311 may include one slope 315 in the middle. Desirably, the first retaining force is evenly applied to the lid 320 to generate a homogenous sealing. In this regard, the first sidewall 31 1 includes three first slopes 315 evenly distributed along the first sidewall 311.

The lid 320 may be made of the same material as the housing 310. And the lid 320 may take on any configuration suitable for covering the opening 314 once the lid is fitted to the housing 310, but generally includes a first edge 321 , a second edge 322, a third edge 323 and a fourth edge 324. The first edge 321 includes at least one second slope 325 corresponding to the at least one first slope 315 on the first sidewall 311 , and the third edge 323 includes a first tab 326 to generate a second retaining force which retains the sealing in a direction substantially perpendicular to the top wall 313 of the housing 310, as will be described below.

The process of generating a sealing between the housing 310 and the lid 320 will now be described with reference to Figs. 4a-4c. Fig. 4a is a perspective view of the embodiment of Fig. 3, illustrating the lid 320 being fitted to the housing 310. Firstly, the lid 320 is placed at a first location relative to the opening 314, for example the location as shown in Fig. 4a, where the first slopes 315 adjoin respective second slopes 325. Then the lid 320 is pushed along the direction Y denoted by the arrow in Fig. 4a as the second slopes 325 engage and slide along respective first slopes 315. As a result, the fourth edge 324 of the lid 320 is pressed against the corresponding periphery of the opening 314 along the direction X denoted by the arrow in Fig. 4a. In such a process, the first slopes 315 exert the first retaining force on the lid 320 via the second slopes 325. As will be understood by the person skilled in the art, the mutual force between the first and second slopes is perpendicular to the surfaces thereof, and the force exerted on the second slopes 325 can be decomposed into a force in the direction X, i.e. the first retaining force, and a force in the direction opposite to the direction Y. The angle of the first and the second slopes can be designed to generate the first retaining force of proper value.

As discussed, a sealing layer 340 is provided between the housing 310 and the lid 320 for the purpose of sealing. The sealing layer 340 is generally made from elastic materials, such as thermoplastic elastomer, and is soft relative to the housing 310 and the lid 320, so that compression deformation occurs substantially in the sealing layer 340. As the second slopes 325 slide along the first slopes 315, the portion of the sealing layer 340 between the fourth edge 324 and the corresponding periphery of the opening 314 is squeezed. Once the sealing layer 340 is squeezed, the tendency of the sealing layer 340 to maintain its original shape creates a seal. In other words, sealing in the X direction is brought about.

It is to be noted that the hardness of the sealing layer 340 may be designed according to specific applications. In one embodiment, the device 300 is used in high pressure applications and a relatively large sealing force is required. In this regard, sealing material of relatively large hardness is desirable. In another embodiment, sealing material of relatively small hardness is used in low pressure applications. Further, the sealing layer 340 can be fixed to one of the housing 310 and the lid 320 in any suitable manner. For example, the sealing layer 340 can be provided in a groove machined into the periphery of one of the opening 314 and the lid 320. Alternatively, the sealing layer 340 can be molded on the periphery of one of the opening 314 and the lid 320, so that sealing failure due to inadvertent misalignment between the sealing layer 340 and the housing 310 or the lid 320 is prevented.

In the embodiment illustrated in Fig. 4a, the first and second slopes are defined by protrusions. As illustrated, the first slopes 315 are defined by generally wedge-shaped protrusions extending from the inner surface of the first sidewall 31 1 to the interior of housing 310. And the second slopes 325 are defined by generally L-shaped protrusions located on the first edge 321 of the lid 320. Any suitable shapes of the protrusions are possible. In one example, the relatively short rib of the L-shaped protrusion is omitted. Furthermore, other suitable configurations of the first and second slopes are also possible. The first slopes 315 may be defined by grooves formed in the first sidewall 311. In this case, the protrusions where the second slopes 325 reside are received by the grooves in the first sidewall 31 1 during fitting of the lid 320 to the housing 310. The configuration by which the first slopes 315 are in engagement with the second slopes 325 is not a limiting factor.

The process of generating a sealing in the direction X is described above. Now, the sealing-generating process in the directions Y and Z will be described with reference to Figs. 4b- 4c, wherein Fig. 4b is a top view of the embodiment of Fig. 3, illustrating the lid 320 fitted to the housing 310 and Fig. 4c is a sectional view taken along line A-A of Fig. 4b.

As is shown in Fig. 4c, the first tab 326 on the third edge 323 engages under the top wall 313 when the lid 320 is being fitted to the housing 310 and is biased in the direction Z, i.e., toward the bottom wall of the housing 310. The top wall 313 thus exerts the second retaining force on the lid 320 via the first tab 326. To facilitate said engagement of the first tab 326 under the top wall 313, the first tab 326 may include a slope such that friction between the first tab 326 and the top wall 313 is decreased.

As will be understood by the person skilled in the art, as the lid 320 is being pushed in the direction Y, both the first retaining force and the second retaining force increase. When the third edge 323 butts against the corresponding periphery of the opening 314, the first and the second retaining forces reach their maximum. At this point, the housing 310 and the lid 320 are fastened together by the fastening means 330, thereby effecting sealing in the direction Y and the direction Z. More specifically, the fastening means 330 exerts a third retaining force on the lid 320 along the direction Y, which keeps the third edge 323 of the lid 320 in abutment against the corresponding periphery of the opening 314, as a result of which the portion of the sealing layer 340 therebetween is kept squeezed resulting in sealing in the direction Y. At the same time, the fastening means 330 exerts a fourth retaining force on the lid 320 at the second edge 322 opposite the third edge 323. The fourth retaining force and the second retaining force jointly keep the lid 320 fixed relative to the housing in the direction Z, so that the portion of the sealing layer 340 between the first and the second edge of the lid 320 and the periphery of the opening 314 is kept squeezed, resulting in sealing in the direction Z. In such a way, three-dimensional sealing on a corner of a device is achieved.

The fastening means 330 may include any manner of fastening components. For example, in one embodiment, the fastening means includes a snap-fit configuration. Specifically, a resilient shoulder formed on second edge 322 of the lid 320 flexes and engages under a ledge formed on the outer surface of the housing 310 upon pressing the lid 320 onto the housing 310. In the embodiment illustrated in Fig. 4c, the fastening means 330 includes a screw hole 431 defined in the second sidewall 312 of the housing 310 and a through hole 432 defined in the lid 320 permitting a screw to be passed through and to be subsequently driven into the screw hole 431 so as to fasten the housing 310 and the lid 320 to one another. In the illustrated embodiment, the screw hole 431 and the through hole 432 are positioned in an inclined direction relative to the normal of the top wall 313 so that the force exerted on the lid

320 by the shaft of the screw is inclined to the normal of the second sidewall 312 and can be decomposed into a force in the direction Z and a force in the direction Y. However, it is not necessary for the screw hole 431 and the through hole 432 to be inclined. As one alternative, the screw hole 431 and the through hole 432 are perpendicular to the top wall 313. In this case, the screw head exerts a force on the lid 320 in the direction Z and the screw shaft exerts a force on the lid 320 in the direction Y.

In the embodiment in which the fastening means 330 is composed of a screw hole 431 and a through hole 432, the sealing layer 340 may include an extension portion 541 , shown in Fig.5, configured to plug and seal the through hole 432 after mounting the screw so as to prevent penetration of water through a seam, if any, between the screw hole 431 and the screw. Furthermore, the extension portion 541 exerts a press force on the screw, resulting from friction between a peripheral surface of the extension portion 541 and an inner surface of through hole 432, preventing the screw from loosening.

In another embodiment of the invention, the lid 320 further includes two second tabs 627 on the fourth edge 324 thereof, as shown in Fig. 6, configured to provide a fifth retaining force along the direction Z which may be subsidiary to the second and the fourth retaining forces. However, one or more than two second tabs may also be provided along the fourth edge 324.

In one embodiment, the waterproof device 300 shown in Fig. 3 is used in a portable, battery-powered device. The housing 310 and the lid 320 retain one or more batteries in the device and jointly provide a waterproof sealing in a closed position.

It should be readily appreciated by the person skilled in the art that various modifications and variations can be made to the embodiments of the invention illustrated and described herein without departing from the scope and spirit of the invention. It is intended that such modifications and variations be encompassed by the appended claims.

Claims

1 . A device (300), comprising: a housing (310), comprising an opening (314) at a corner thereof, the opening being defined by a first and a second sidewall (311 , 312) and a top wall (313), the first sidewall

(31 1) comprising a first slope (315);

a lid (320), intended to be fitted to the housing (310) to cover the opening (314), the lid (320) comprising a first (321), a second (322), a third (323) and a fourth edge (324), the first edge comprising a second slope (325) corresponding to the first slope (315), and the third edge comprising a first tab (326);

a fastening means (330), configured to fasten the housing (310) and the lid (320) to one another; and

a sealing layer (340), configured to seal the housing (310) and the lid (320), the sealing layer being made of soft material relative to the material of the housing (310) and the lid (320),

wherein, when the lid (320) is fitted to the housing (310) by pushing it along a first direction (Y), the first slope (315) and the second slope (325) are in engagement with one another to generate a first retaining force along a second direction (X) perpendicular to the first direction (Y), the first tab (326) is inserted beneath the top wall (313) to generate a second retaining force along a third direction (Z) perpendicular to the first direction (Y) and the second direction (X), and the fastening means (330) generates a third retaining force along the first direction (Y) and a fourth retaining force along the third direction (Z).

2 . The device of claim 1 , wherein the sealing layer (340) is molded over the periphery of one of the lid (320) and the opening (314).

3. The device of claim 1, wherein the fastening means (330) comprises a first portion

(431) in the second sidewall (312) of the housing (310) and a second portion (432) on the second edge (322) of the lid (320).

4 . The device of claim 3, wherein the first portion (431) is a screw hole, and the second portion (432) is a through hole permitting a screw to be passed through and to be subsequently driven into the screw hole.

5 . The device of claim 4, wherein the screw hole and the through hole are positioned in an inclined direction relative to a normal of the top wall (313).

6 . The device of claim 4, wherein the sealing layer (340) further comprises an extension portion (541) configured to plug and seal the through hole after mounting the screw.

7 . The device of claim 1, wherein the sealing layer (340) is based on a thermoplastic elastomer.

8 . The device of claim 1 , wherein the lid (320) further comprises at least one second tab

(627) on the fourth edge (624) thereof, configured to provide a fifth retaining force along the third direction (Z).

9 . The device of claim 1 , wherein the first tab (326) has a slope configured to facilitate inserting the tab (326) beneath the top wall (313).

10 . A portable, battery-powered device, comprising the device of claim 1, wherein the housing and the lid are configured to retain a battery in the device and jointly provide a waterproof sealing in a closed position.