Metal Frames for Raising Storage Cases Above Floor Surfaces
Extensive series of storage units often are used to house natural history collections. Typically, these units rest on floor surfaces, or on wooden frames if there is a need for leveling floor irregularities. It is not unusual for organic and inorganic materials to accumulate between and under these storage units, providing refuge and nutrients for insect pests. By positioning storage units above floor surfaces, debris can be removed with periodic house-keeping measures. In turn, the absence of debris accumulation can be more effective in solving pest problems than the use of toxic chemicals. Raising storage cases above floor surfaces can provide other benefits, such as protection from floods.
Stephen L. Williams
Natural Science Research Lab.
Museum of Texas Tech Univ.
4th Street and Indiana Avenue
Lubbock, TX 79409 USA
Tel (806) 742-2486
Fax (806) 742-1136
Stephen L. Williams
One method of raising storage units above floor level has been described by Williams and McLaren (1990). In this case, frames are constructed of U-shaped steel channels and supplementary hardware (Fig. 1). The variety of supplementary hardware makes it possible to customize any type of rack for storage purposes.
Figure 1. Metal frame used for raising storage cases above floor surfaces.
The channel has a continuous slot with a pair of inward turned lips on one side. Special nut and bolt assemblies fit inside the channel and make it possible to connect other frame components.
The legs for the frame consist of a base, head, and an interconnecting stud constructed of die-cast aluminum. The stud includes a threaded portion which accommodates a square nut that provides a mechanism for adjusting the height of the frame. If the height range is inappropriate other stud sizes are available.
Each frame for a series of storage units has two primary channels that extend the length of the row of cases to be raised. To facilitate handling of assembled frames, the length of the channels probably should not exceed 4-5 meters. Shorter sections of the channel are positioned between and perpendicular to the two primary channels to provide stability to the frame and support for individual storage units.
The depth of the frame should be about 20cm less than the depth of the case so that the front and back of the case hang over the frame (Fig. 1). This allows easier positioning of cases, prevents the leg-assemblies from being exposed, and provides a better barrier against insects by making doorways to cases less accessible. If cases are set back-to-back, two longer pieces of channel can be used on the ends to connect the two rows of frames together. Sufficient space should be allowed between the two frames to keep the leg bases from overlapping.
Materials Tools Supplies
- Aluminum frame supports (legs)
- Flat washers, 3/8in
- Heavy hammer
- Hex head cap screws, 3/8in x 1in
- Lever or crowbar
- Nuts, hexagonal
- Socket wrench
- Steel channel, U-shaped
- Tape measure
- Obtain the parts of the frame and position them in the work area.
- With channel slots up, bolt the head of the leg assembly to the connecting channels (Fig. 2).
Figure 2. Enlargement of leg parts.
- Assemble the periphery of the frame first, followed by the inter-connecting parts.
- After the frame is assembled, flip it over and place it in the desired position on the floor.
- Starting with the corners, lift the frame and insert the assembled base and stud of the leg into the head that is bolted to the frame. It may be helpful to pre-set the adjustable nut on the stud at a specified distance (for example, 2cm) from the top, particularly for the corner and middle legs.
- After all of the legs are placed under the frame, position the entire structure in its permanent location on the floor (Fig. 3).
Figure 3. Fully assembled frame ready for use.
- With the frame in its desired position, level the entire structure using the adjustments on the legs. It may be more effective to level the ends first, followed by the primary channels.
Because longer sections of the channel will tend to sag, it will be necessary to provide appropriate support about every two meters before any effort at leveling the entire frame is attempted.
- After the sides of the frame are leveled, level the interconnecting metal channel.
- After assembly, positioning, and leveling are completed, place the cases on the frame. Empty cases before placement.
- As cases are installed, make minor adjustments of the legs to insure the best position for the cases.
- Check alignment of doors and space between the cases. When adjustments are necessary it is more effective to use a lever to raise the loaded frame and then manually adjust the level of the nut that controls the frame height.
The metal frames described above were selected over other possibilities because of competitive costs, maximum versatility, and quality materials.
If properly constructed, the frames can easily accommodate the weight of single- or double-stacked storage units. However, care should be taken to provide enough leg supports over the floor area so that the weight capacity of the floor is not exceeded.