Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-03-14
2003-12-02
Schuberg, Darren (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C360S097010, C165S121000, C403S024000, C248S581000
Reexamination Certificate
active
06657858
ABSTRACT:
FIELD OF THE INVENTION
The invention is related to a housing for data storage devices or for accommodating such data storage devices.
BACKGROUND OF THE INVENTION
To operate for example a personal computer, usually a computer system is required comprising a disc drive, a central processing unit, a floppy disc drive as well as other devices which are assembled within a cuboid shaped housing. Fans are usually installed in such housings, maintaining an air-flow through the housing to facilitate the cooling of electronic and mechanic components while the computer is operating.
The acoustic noise emitted by such computers is often perceived as unpleasant by computer users. Regarding the acoustic noises solely generated by the fans, these are located in a middle-frequency range and therefore act subjectively less disturbing as the high-frequency acoustics, which are radiated by the computer and the alternating mix-mode noises generated by the mixture of noises. The high-frequency sound involving frequencies that may extend up to 9 kHz or more, are mainly generated by the drive motor of the data storage device. The disc media is driven at high velocity by the drive motor. Even if the high-frequency noise radiated by the housing and through the air vents only has a relative low amplitude, it annoys due to its permanent presence and particularly in a room (i.e. large area office) where a number of such computers are in use with the according noise emission. In such rooms a permanent whistle and warble is audible, which impairs the health and labor capacity of those who are working in such environment.
Due to severe competition, PC's and workstations have strongly diminished in price value and are meanwhile considered as mass products. A warranty period of 36 months, is meanwhile at least granted by all large vendors world wide and treated as a usual practice. Due to the fast technological progress the purchase value of a computer declines within shortest time, long before the warranty period expires. This leads to the circumstance that manufacturers and suppliers proceed to carry the risk of RMA handling, despite the fact that the commodity has lost its value to a great extent. RMA cases are mainly caused by those computer components which contain moving mechanical or force-driven parts. The failure of the mass-storage-device, the disc drive, usually causes the greatest single damage for the user as well as the manufacturer or supplier. Modem disc drives are sensitive against shock and in some instances, due to elevated power consumption, also against overheating. Already slight shocks may lead to a head crash. Such shock influence caused by the user, onto a commonly constructed computer, are not provable for the manufacturer or supplier. Therefore such defects automatically lead to a warranty obligation.
The state-of-the-art technology provides a variety of single or even combined solutions for the noise-reduction of computer housings, the cooling of oscillating devices and shock absorption for sensitive devices. The following publications on the state-of-the-art are considered as known.
DE-GM 297 04 870, DE-OS 38 23 656, DE-GM 296 02 346, DE-OS 43 14 199 U.S. Pat. No. 5,192,143, U.S. Pat. No. 5,510,954, U.S. Pat. No. 5,596,483, U.S. Pat. No. 5,287,244 U.S. Pat. No. 5,214,459, U.S. Pat. No. 5,668,697, U.S. Pat. No. 5,654,875, U.S. Pat. No. 4,812,932, U.S. Pat. No. 5,235,482, U.S. Pat. No. 5,469,311, U.S. Pat. No. 5,638,895, U.S. Pat. No. 5,801,899
In the DE-GM 297 04 870 an extensive de-coupling of body-oscillation is achieved by suspending the disc drive in o-rings made of rubber-elastic materials and lining the inner sides of the computer housing with rubber-cork mats. The disadvantage here is, that depending on the type of disc drive model, cumbersome adjustments of the suspensions are to be taken care of. In addition it is uncertain whether a slipping of the device during transport is prevented under all circumstances. This type of suspension contradicts the emphasized manufacturer specifications regarding the firm assembly of a disc drive. A disc drive suspended within a 5¼ inch slot-frame is positioned in the immediate rear of the computer front lid of standard computer housings. Thereupon one has to permanently shut a front lid to fully reduce the noise. A disc drive suspended within a 5¼ inch slot-frame can only be cooled exclusively by a fan from the bottom or with tiny fans from the side. An air stream only blowing at the bottom is often not sufficient. For the purpose of secure cooling, disc drive manufacturers usually prescribe that an air stream has to be maintained above the top side as well as the bottom side. As no further passive cooling is provided for the disc drive, a failure of the fan will lead to overheating in most instances. This is particularly fatal when a computer is operating unattended and no immediate response is given to a system warning indicating fan failure. Even if a fan failure recognition invokes an automatic system shut-down, this is equivalent to a system failure which has to be repaired prior further operation. Eventually the application of cork-rubber mats does not meet the UL regulations regarding fire hazards in electric devices.
The DE-OS 43 14 199 describes an artifice for conductive cooling of oscillation attenuated devices which are mounted within a closed housing. It is uncertain if the here described method of cooling is sufficient enough to cool, disc drives dissipating up to 20 W, exclusively by thermal conductive heat-relief, with an appropriate magnitude. Computers are specified with an ambient operating temperature of 35° C. for the medium latitudes and 40° C. for the warmer regions. However, disc drives available in the mass market are only offered with a maximum specified surface temperature of 55-60° C. The specified thresh hold temperature for maximum life time is most often located 10-15° C. below the maximum rated temperatures. This signifies that for a long life time a very effective cooling has to be implemented. For reasons of extensive assembly requirements the here described method is unusable for the mass market in any instance. Furthermore disc drives may not be mechanically altered due to warranty considerations. An effective heat-relief by means of copper braiding, is only achieved by soldering or welding onto the disc drive.
In the U.S. Pat. No. 5,192,143 shock absorbers for disc drives are described. It is not evident if these shock absorbers also enhance an effective noise reduction. Furthermore it is doubtful that these shock absorbers are sufficient to safe guard a disc drive against a shock of 30 g applied onto the housing during continuos operation. A shock of 30 g is already reached when a computer gets hit by a vacuum cleaner. Regular 3½ inch disc drives are specified with a maximum shock stress of 10 g during operation. No concerns about cooling the disc drive are to be extracted from this publication.
The so far as best known state-of-the-art is described in the U.S. Pat. Nos. 5,510,945 and 5,596,483. However, the disadvantage here is the hermetically encapsulated disc drive. Thereupon an active or passive direct air cooling is not possible. Here, the cooling of the disc drive is exclusively only achieved by thermal conductive heat-relief. The necessary air vents on the deck of the computer does not conform with any housing standards. The guided air stream depends too much on the implemented components and is already warmed up prior to reaching the location of the described heat-sink. No redundant cooling is existing. Two or even more only very slowly rotating fans and a convection air-stream guided through the power supply, are in total only sufficient for a computer equipped with low-power components. The encapsulation of the disc drive restricts the cooling to such an extent, that this method is not applicable in conjunction with powerful disc drives (refer to c't magazine edition 19/1998, start page 136 on page 142). The here described cooling pouch filled with liquid is
Duong Hung Van
Hopen Anton J.
Smith & Hopen , P.A.
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