Background of the Invention
1. Field of the Invention
The invention relates to a watertight protective device for holding a measuring or display device, and more particular to a protective device having a protective housing, the inside contour of which is shaped so conform with an the outer dimensions of a contained measuring or display device.
2. Description of the Related Art
Protective devices serve to hold measuring or display devices in a water- and dust-tight fashion, with the operation of the device not being adversely affected by the protective device. Known protective devices consist of flexible transparent protective sheaths with a pouch design that can be sealed to make them water- and dust-tight. Operation of a measuring or display device placed in the protective sheath is retained because of the flexibility of the sheath. To guarantee flexibility, such protective sheaths are made of a relatively thin plastic material so that the lifetime of such sheaths is limited in the frequently harsh operating conditions to which measuring devices are subjected. Under extreme operating conditions, there is frequently the risk that the measuring or display device will be damaged by external application of force since the thin sheath cannot withstand such external forces.
Another disadvantage of known protective sheaths is that even minor damage to the protective sheath surface is sufficient for water tightness to be no longer guaranteed. In addition, the protective sheath may prevent the measuring device from measuring the provided amount, since the measuring device is wholly contained within the protective sheath.
Summary of the Invention
Accordingly, it is an object of this invention to provide a protective device which is water-tight and dust-tight, and which will protect a contained display or measuring device against the external application of force.
To achieve this object, a protective device is provided having a protective housing made from a dimensionally stable material. The inside contour of the protective housing is shaped to conform with the outer dimensions of the display or measuring device so that there is essentially zero play between the protective device and the contained device. Additionally, the protective housing may have an operating area that is transparent and yields elastically to enable operation of the contained device.
By providing a protective device of this nature, the dimensionally unstable protective sheaths previously used may be replaced by a dimensionally stable housing in which, as the result of a suitable choice of materials, the operating and display elements of the inserted measuring or display device remain visible through the housing wall and can also be operated. The essentially zero-play accommodation of the measuring or display device offers optimum protection against external applications of force. The protective device so designed is largely insensitive to objects, especially those with sharp edges, that would have damaged the surface of conventional protective sheaths, since the wall thickness is much greater than the wall thickness of conventional protective sheaths. Thus, the lifetime of the protective device is increased.
In one embodiment, the inside contour of the protective device is shaped to conform with the contours of the measuring or display device it is designed to contain. By doing this, the outer dimensions of the protective device may be minimized while still performing the sealing and protecting functions.
To facilitate insertion and removal of the measuring or display device, it is preferable to form the housing from an upper part and a lower part which are releasably connected with each other. The connection of the lower housing part and the upper housing part can be formed from a circumferential groove mounted on either the upper or lower housing part and a circumferential rib formed on the other housing part. In operation, the rib engages the groove to join the upper housing part and the lower housing part. In this manner, a reliable seal may be formed between the two housing parts by using an elastically flexible material with a rib that is at least slightly larger than the groove. The sealing effect of the connection between the upper housing part and lower housing part can be additionally increased by providing sealing lips on the groove and/or rib.
Optionally, the upper housing part may be connected to the lower housing part by a hinge, for example a film hinge, which can prevent one of the two parts from being lost. Other types of hinges, such as pin hinges or living hinges may also be used.
To ensure complete operation of the measuring or display device placed in the protective device, an operating area may be provided on the protective device behind which the operating and/or display area of the measuring or display device is located. In one embodiment, the housing portion that serves as the operating area of the protective housing has a reduced wall thickness. In this manner, it is possible for an user to operate buttons on the measuring or display device, as long as the operating area is capable of sufficient elastic deformation by finger pressure. From a manufacturing standpoint, it is advantageous to form the operating area integral with the protective housing, and from the same material.
For example, transparent soft PVC can be used as the material for making the protective housing described above. When this material is used, a protective device can be obtained that is transparent not only in the operating area but everywhere. In addition, thermoplastic elastomers (TPE) or thermoplastic polyurethanes (TPU) can be used to make the protective housing.
Another embodiment provides for providing recesses, preferably on the side facing away from the operating area, that can serve to fasten the protective housing, including the measuring or display device accommodated therein, to a matching mount. In order to achieve greater resistance to twisting of the protective device and hence improved handling ability, at least one reinforcing strip may be provided. The reinforcing strip may be made of the same material as the protective housing or different material. The reinforcing strip offers greater protection for the measuring or display device located in the protective device against outside forces.
In order to connect a measuring or display device placed in the protective device with a measuring sensor or other peripheral device for example, an opening is provided in the protective device through which a plug can be guided in a watertight fashion and then connected with the measuring or display device.
The sealing effect in the vicinity of the opening can be ensured in an especially simple fashion by adapting the shape and size of the opening to the shape and size of the plug, so that the protective housing abuts the plug in the area of the opening over its entire surface and therefore forms a watertight seal. Optionally, a sealing lip may be located in the opening to provide a linear contact all the way around the plug that has been inserted or against the housing of the measuring or display device, thus producing a watertight seal. A lip of this nature is advantageous in that the plug can be inserted through the opening by the application of a low force.
A stand may be provided on the housing and connected to the housing by a hinge so that the hinge may be moved in and out (similar to a picture frame). In this manner, the stand may enable the measuring device, contained in the protective housing, to stand upright on a desk or other surface. Recesses may be provided on the housing and used to fasten the protective housing to a mount or to a rotatable stand.
An area of reduced wall thickness is preferably provided on the protective housing on a side that is opposite a removal opening. This area can be deformed by a user in order to shove the inserted measuring or display device toward the removal opening to remove it. The measuring and display device advantageously abuts the area of reduced wall thickness at a pusher .
Brief Description of the Drawings
The preferred embodiments of the present invention will now be described more specifically with reference to the attached drawings, wherein:
FIG. 1 is a cross-sectional view of one embodiment of a protective device according to this invention containing a measuring or display device;
FIGS. 2(a) and 2(c) are cross-sectional views of protective devices according to this invention;
FIGS. 2(b) and 2(d) are enlarged cross-sectional views of the encircled portions of FIGS. 2(a) and 2(c) respectively;
FIG. 3(a) is a cross-sectional view of a protective device according to this invention;
FIGS. 3(b) and 3(c) are cross-sectional views taken along lines X--X and Y--Y of FIG. 3(a) respectively;
FIG. 3(d) is an expanded, cross-sectional view of the watertight seal encircled in FIG. 3(a);
FIG. 4 is a perspective view of a lower housing part into which a measuring or display device has been partially inserted;
FIG. 5 is a front view of a protective device according to the invention with the measuring or display device inserted, with a upper housing part not being pushed completely onto a lower housing part as shown; and
FIG. 6 is a perspective view of a protective housing with the stand deployed. In these figures, unless stated to the contrary, the same reference numerals are used to mark the same parts and have the same meanings.
Detailed Description
As shown in FIGS. 1 to 3(d) the protective device according to this invention may include a protective housing 1 that has a lower housing part 2 and an upper housing part 4.
The protective housing 1 has an operating area 6 behind which an operating field 108 and a display field 106 of an inserted measuring or display device 100, not shown in cross section, are located. Operating area 6 is formed at a location in the protective housing corresponding to a display field 106 and formed to be elastically deformable under ordinary pressure from a finger 50. One way of forming the protective housing to be elastically deformable is to provide a reduced wall thickness in this area. Alternative ways of rendering this portion elastically deformable may include altering the chemical composition of the material in this portion of the device, such as by adding solvent, or by using a different material to form this portion of the protective housing. By providing an elastically deformable operating area 6, it becomes possible to operate a pushbutton 104 located on the device 100 through the protective housing 1.
As shown in FIG. 3d, the lower housing part 2 has a circumferential rib 12 that engages a circumferential groove 14 in the upper housing part 4 when the lower housing part 2 is connected to the upper housing part 4. A sealing lip 8 located in the circumferential groove 14 guarantees the watertightness of the protective housing in the corresponding areas.
A plug 102 from the measuring or display device 100 is brought out through an opening 18 in upper housing part 4. A circumferential sealing lip in the vicinity of the plug opening 18 guarantees a watertight feedthrough of plug 102 through the protective housing 1. Depending on the design of the measuring or display device 100, a sealing lip 28 abuts the measuring or display device 100 in a watertight fashion, or does so with respect to plug 102, as shown by FIGS. 2(b) and 2(d). In the embodiment shown in FIG. 2(b), the housing of the measuring or display device 100 abuts the plug 102 in a watertight fashion.
FIG. 3(b) illustrates a cross-sectional view of the protective housing 1 along a section line X--X in FIG. 3(a) to better show the relationship between the groove 14 of the upper housing part 4 and the sealing rib 12 of the lower housing part 2 in a top view. FIG. 3(b) also shows the sealing forces F that results between the groove 14 and the rib 12 of the lower housing part 2. The upper housing part 4, groove 14 and rib 12 are designed so that the sealing forces F in each case are the greatest at the middles of the four sides, and taper off toward the corners. The lengths of the force arrows symbolize the sealing forces F produced by the groove 14 and rib 12 in a quantitative manner.
FIG. 3(c) is an enlarged cross-sectional view taken along line Y--Y in FIG. 3(a) and clearly shows the contours of plug 102, which in this embodiment is made approximately rectangular, and also shows the contours of the opening 18 of the upper housing part 4. The contour of the opening 18 may be formed by sealing lip 28. The dimensions of the plug 102 are slightly larger than the dimensions of the plug opening 18, so that when the plug 102 is inserted into the measuring or display device 100, the upper housing part 4 abuts the plug 102 in a watertight fashion in the vicinity of the plug opening 18. As indicated by FIG. 3(c), the greater size of plug 102 with respect to the opening 18 or sealing lip 28 is at a maximum in the middle of each of the four sides of the rectangular plug 102 and decreases toward the corners. This ensures that the sealing forces are greatest at the middle of each of the sides and decrease toward the corners.
As shown especially in FIGS. 1, 2(a), 2(c) and 3(a), the lower housing part 2 has an area 24 of reduced wall thickness adjacent a pusher 26 designed as a projection on a side that is opposite a removal opening. The measuring and display device 100 inserted in the lower housing part abuts the pusher 26. The area 24 is designed so that it is deformable by an user by the application of external force to push the measuring or display device a short distance out of the lower housing part 2 when the upper housing part 4 has been removed. This facilitates removal of the measuring or display device 100 from the protective housing 1.
FIG. 6 is a perspective view of an embodiment of a protective housing according to the invention that has a stand 22 on the side of the protective housing opposite the operating area 6. The stand may be configured to be capable of being folded in or out by means of a hinge 23. In the unfolded state, the stand 22 allows the protective housing 1 to stand on a surface, with operating area 6 in the deployed state preferably being tilted at an angle with respect to the surface to facilitate operation of the measuring or display device 100. Preferably, the stand 22 has rubber projections 25 or similar devices at its lower end to generate friction between the stand 22 and the surface.
As is particularly clear from FIGS. 4 to 6, reinforcing strips 10 are located on the protective housing. These strips increase the resistance of the protective housing to twisting and also serve to protect the measuring or display device 100 located inside the protective housing against the application of external forces. As is also evidence from FIG. 4, recesses 20 may be provided on the side 16 facing away from the operating area 6 to fasten the protective housing 1 to a mount (not shown). Preferably, two of the recesses 20 may also be used to attach the protective housing to a stand 22.
It should be pointed out that upper housing part 4 and lower housing part 2 do not necessarily need to have the shape and size shown in the figures. Rather, any parts may be used as upper housing part 4 and lower housing part 2 that produce a similar protective housing 1 when assembled. For example, protective housing 1 can be divided to form two shell halves which mate to contain the measuring or display device 100.
It is understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the scope and spirit of this invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but rather that the claims be construed as encompassing all the features of patentable novelty that reside in the present invention, including all features that would be treated as equivalents thereof by those skilled in the art which this invention pertains.
This application claims priority from German Patent Application No. 296 12 454.0, the content of which is hereby incorporated by reference.