Medium Duty Racks
A & J Manufacturing Company offers a medium duty electronic equipment rack/cabinet, Series 150, with a large variety of equipment installation kits. These basic installation kits are shock and vibration qualified and are also interchangeable between the light duty and heavy duty rack cabinets. The standard medium duty rack-cabinet is 72 inches high, 22.3 inches wide, and 26 inches deep with a partial bottom panel, full top panel and is of modular bolted-together construction. The 150 Series rack-cabinet uses the A & J 6500 extrusion that has a slightly greater section modulus than the 2500 extrusion, which enables the rack to support medium to heavy equipment payloads in a shock and vibration environment.
The 150 Series section modulus enables the open frame rack to support a six hundred pound (600#) payload and a nine hundred pound (900#) payload in the enclosed cabinet. The successful performance of the rack-cabinet with these payloads can best be achieved if the center of gravity (CG) can be kept dimensionally at or below the middle of the rack and about the center axis. A variety of the medium duty racks/cabinets have been qualified to meet the requirements of MIL-S-901 shock and MIL-STD-167-1 vibration and environmental test methods of MIL-STD-810. A summary of the test reports is listed in Section III and copies of the reports are available upon request. The 150 Series rack is also recognized as a military standard and has been assigned National Stock Numbers.
|Model Number||Height of Rack (Inches)|
The rack/cabinet has a front and rear nineteen (19) inch panel width. The rack-cabinet has two (2) front RETMA Bars, which have the standard EIA panel mounting hole pattern, and a vertical T-Nut slot. Two backup bars containing the T-Nut slots are located in the rear. A rear EIA hole pattern is optional. A & J uses the four (4) T-Nut slots for the majority of the electronics kit mounting/interface to the rack/cabinet. The T-Nut slot dimensions from front to rear and side to side are maintained throughout the standard lines of light, medium, and heavy duty rack-cabinets to facilitate the interchangeability of installation kits. See Section V Alphabetical and VI Numerical for kit numbers and features. The use of the T-Nut slot provides infinite vertical adjustments without the necessity of drilling mounting holes in the rack-cabinet. The RETMA Bar EIA holes have stainless steel treaded inserts that may be removed and replaced when stripped or worn. A continuous integral EMI/RFI gasket groove is contained in all frame members. RETMA bars, and backup bars enable the rack-cabinet to be configured at any time to meet this requirement.
An X-Brace is included as a standard feature in all 150 Series delivered racks and cabinets to provide torsional stiffness and to keep the vertical columns from “bowing.” If the rack or cabinet payload distribution is maintained as suggested, a deck mounted and free standing configuration without sway bracing can be achieved. A clear area of one-half (.5) inch should be maintained all around the rack for free excursion under potential shock conditions. If racks or other cabinets are adjacent, they should be fastened together at the top, using the A & J cabinet joining kit. Half inch (.5) diameter CRES high strength bolts should be used when mounting or installing the rack on a foundation. If the weight distribution results in a higher center of gravity or excessive payload, an additional X-Brace or sway brace should be considered. When the fragility of the electronic components demand shock and vibration attenuation, the medium duty rack may be configured for an isolation system.
The bolted together construction provides the capability of disassembly of the rack-cabinet for passage through narrow openings and passageways and around tight corners. The rack-cabinet may be reassembled and still maintain its original structural integrity. When reassembling the rack-cabinet, the following type tools and torque values should be observed together with an application of component adhesive to the joining bolts:
|Bolt Size||APEX Tool Number||Torque Value(Inch Pound)||Adhesive Type (or Equivalent)|