By Susan Witkowski
Whether it is a server, power supply, keyboard, fan tray or some other chassis configuration, there are two main aspects to consider when designing slides into electronic enclosures; the cabinet construction and the chassis – or drawer.
The attributes of these two components affect the overall enclosure configuration and the selection of slides, brackets and cable carriers.
Telescopic slides and brackets are often used to mount drawers into cabinets. Slides also provide the means to safely open drawers while giving access to critical contents. Finally, wire management or cable carriers must be added to protect wiring. Successfully combining these elements can be a significant challenge.
Often, integration problems can be traced back to cabinet configuration and related spacing issues. The following takes a systematic approach through the key aspects that influence a successful assembly.
Know the cabinet and the standard measures
Cabinets vary according to manufacture and intended use, displaying unique column shapes, thicknesses, materials and placement. These construction variances have a significant effect on the enclosure design. Be sure to obtain detailed specifications from your cabinet manufacturer.
Cabinets generally contain four or more rails (columns/uprights)
There are front rails, rear rails and optional mid-rails
There is no limitation on overall cabinet height
Most electronic cabinets are based on international standards and these dimensions are part of the equation that determines the available space for cabinet components.
The minimum opening width between cabinet rails is generally 450mm/17.72" for 19" wide cabinets.
Cabinet mounting rails carry a repetitive pitch pattern of mounting holes in a vertical sequence 15.87mm, 15.87mm, 12.70mm, 15.87mm (⅝", ⅝", ½", ⅝") and so forth.
The outside cabinet dimensions (footprint) are always greater than the cabinet mounting rail dimensions. The mounting rails are located inside the cabinet enclosure and components must be planned to fit within the rail dimensions
The actual distances between the width and depth of the mounting rails will vary according to manufacture.
Know the cabinet rail construction, rail configuration and mounting holes
Check if the cabinet has adjustable or non-adjustable mounting columns. Some cabinets include a mid-rail that may be adjustable. Rails come in an assortment of profiles and the shape affects the cabinet's internal available space and therefore the selection of components. Rails also have several kinds of mounting holes and locations. It is important to get the exact details on the type of mounting holes offered on the cabinet.
Chassis size
Chassis is the term for an electronic drawer. When designing the chassis be sure to include the slide and bracket dimensions when determining its width.
Vertical measurements are also critical to the installation. The minimum height of a chassis is based on a standard nominal unit increment of 44.45mm or 1U. The height of the chassis plus the space required between the drawers must be accounted for when planning the overall number of chassis to be installed. The vertical dimensions are further affected by the need to match the chassis relative to the spacing of the mounting holes on the rails and the positioning of the slides, brackets and cable carriers.
Know the slides
Selecting the correct slide is based on several factors including:
Anticipated chassis load
Distance of chassis travel required; slides offering full extension or over-travel provide the best access to chassis contents (illustration)
Cabinet depth
Slide-to-cabinet mounting bracketry
Required slide features, for example, locks, hold-in or out, disconnect
The mounting position of the slide on the chassis is affected by factors such as bracket alignment, pitch pattern, chassis contents and centre of gravity. Remember also that the smaller the slide profile the more space is available for the chassis.
Know how much working space is available
If some basic dimensions are known, the space available for the remaining components may be determined. For example, by knowing the slide width, bracket thickness and cabinet opening, the chassis width can be determined.
By identifying all of the component variables, planning a compatible assembly becomes much easier.
Accuride has evolved from beginnings in the 1960s making telescopic slides, Accuride is now at the forefront in the design and manufacture of access and movement
Source:www.isnare.com |
