Stationary batteries are specifically designed for float applications, that is, as standby power in the event of a power failure. Stationary batteries are usually maintained at a full-state-of-charge and in a ready-to-use condition typically by floating at a constant preset voltage. Standby batteries are used for standby or operational power in the communications field, utilities, for emergency lighting in commercial buildings and uninterruptible power supplies.
Uninterruptible power supplies are systems that back-up computers and communication networks. Sealed lead-acid cells and/or batteries may comprise the power source. The uninterruptible power source allows for the orderly shutdown of computers when there is a sudden interruption in the primary electrical source, such as during a power outage, and provides back-up power for communications networks. The uninterruptible power supply also will accommodate short, or intermittent, losses in power. When there is a power interruption, the batteries in the uninterruptible power system can be subject to rapid discharge.
The sealed lead-acid stationary cells and/or batteries used for industrial applications where the power requirements are high and quite demanding are typically comprised of from several to a large number of individual sealed lead-acid cells connected to one another to form a battery with the desired capacity and power requirements. The individual sealed lead-acid cells may be connected in series, in parallel or in suitable combinations of series and parallel to form a battery with the desired capacity and power requirements. External connections are typically made between the negative and positive terminal posts of the respective cells.
Because of space considerations, these large capacity cells need to be placed on racks, cabinets or the like in an attempt to minimize the space requirements. Still further, the face of the cells including the cell terminals and terminal connections must be properly covered to prevent accidental human contact and electrical shorting. For Zone 4 applications, i.e. locations where high seismic conditions can occur, there are even further stringent requirements that must be met to insure that the cells are properly covered and adequately secured in the racks should such high seismic conditions occur. A complicating factor is that although the cells must be properly covered, they also demand routine monitoring and maintenance. Accordingly, the cell covers must be periodically removed to permit access to the cells.
To satisfy these diverse requirements, the cell tray cover systems currently being used, insofar as it can be ascertained, may include metal hardware or plastic spring action supports to secure the cell covers to the rack and tray assembly. Unfortunately, both the metal hardware and plastic spring action supports present major drawbacks. For example, the metal hardware (i.e. "nuts and bolts") requires a number of tools for installation and removal, and since the hardware is electrically conductive, the risk of electrical shock is necessarily exacerbated. Additionally, the metal hardware requires insulation with electrically nonconductive material after installation has been performed. The installation and removal of the hardware is also cumbersome since tools, which may also be electrically conductive, are required.
The plastic spring action supports, which serve to clip the cover onto the cell tray assembly, may offer some improvements over the metal hardware, although still not entirely effective. The plastic supports typically used do not provide the necessary strength and rigidity to support larger sized covers. Consequently, the plastic supports may allow the cell cover to sag and in some cases to even fall off of the cell tray assembly. Insofar as applicants are aware, the plastic spring supports in use lack universality. It is therefore the case that different sized plastic spring supports are used with different sized covers. Still further, a cover utilizing the plastic spring supports may also be cumbersome to install or remove.
It is accordingly a principal object of the present invention to provide a cell tray assembly and cover system for standby applications which effectively and efficiently minimizes the likelihood of accidental contact with cells and batteries during installation and removal of the cover supports.
Another object of the present invention provides a cover system that may be readily attached to, and removed from, a cell tray assembly so as to provide enhanced flexibility in use.
Yet another object of the present invention provides a cover system that may be used with a wide variety of cell and battery applications.
A further object is to provide a cell tray assembly and cover system which is cost-effective and which can be readily manufactured.
Another object of the present invention lies in the provision of such a system which satisfies the requirements for use in high seismic areas, specifically UBC Zone 4 applications.
These and other objects and advantages of the present invention will be apparent from the following descriptions and drawings. While the present invention may be used with any batteries or cells that satisfy the requirements of the particular application, it will be described herein in conjunction with sealed lead-acid cells (often termed "VRLA" cells, i.e., valve-regulated lead-acid).