Support tripod

A tripod has an adjustable top plate that supports an equipment foot. The support legs each comprise paired plates. Interposed between the paired plates is a damping material. The damping material damps the tripod and inhibits resonance from passing through the tripod to the supported equipment.

FIELD OF THE INVENTION 
The invention relates to a damped support tripod and leveling stand. 
BACKGROUND AND BRIEF SUMMARY OF THE INVENTION 
In a cleanroom environment, such as in semiconductor manufacture, there is 
typically a raised floor supported on a concrete sub-floor. The sub-floor 
is usually characterized by `pop outs` or large circular holes for utility 
requirements. An exemplary cleanroom can have a 24" high raised-floor over 
a concrete sub-floor. The sub-floor can have a grid of 14" diameter holes 
or pop-outs on 24" spacing. 
The installation of various semiconductor fabrication, inspection and 
process equipment in a cleanroom environment having a raised floor 
requires special consideration regarding the support of such equipment. 
Typically, such equipment is either too massive or too vibration sensitive 
to be placed directly on the lightweight raised floor. A structural 
support is required to "bridge" the floor height. The support must be a 
stiff, non-resonant structure having a high load capacity, thereby 
extending the rigidity of the concrete subfloor to the height of the 
raised cleanroom floor. 
Supports, such as concrete blocks and welded steel frame structures have 
been used, but lack of portability, cost and the need to design a frame 
structure for each piece of supported equipment are among their drawbacks. 
Tripod leveling stands supporting a damped support plate have also been 
used to support the equipment. 
Regardless of the support used, an opening is formed in the raised floor in 
order that the equipment foot can directly engage the support. 
It is desirable that there be positioning flexibility in the structural 
supports to allow for alignment of the support directly underneath the 
equipment feet (point load). It is also desirable that the integrity of a 
"flow through" design in a cleanroom be maintained by maximizing any air 
flow between the cleanroom and the space defined by the raised floor and 
the sub-floor. 
The invention embodies a rigid support tripod that satisfies the objectives 
of rigidity, non-resonance, flexibility and high load capacity. The tripod 
has a top plate that supports an equipment foot. The tripod is configured 
such that it can allow the equipment to be mounted in any configuration 
over the sub-floor, regardless of pop-out locations. The tripod is 
adjustable such that the top plate can be made co-planar with the surface 
of the raised floor. Further, the top plate is dimensioned such that it 
mates with the opening in the raised floor to maintain the rectangular 
grid pattern of the raised floor. 
Broadly the invention comprises a tripod for equipment support. The tripod 
has damped adjustable legs. The top plate is moveable such that it can be 
positioned to match the opening formed in the raised floor.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
Referring to FIGS. 1 and 2, tripods 10 are shown supporting a load in a 
cleanroom environment. The cleanroom is partially shown and comprises a 
sub-floor 12 having knock-outs 14. A raised floor 16 is spaced above the 
sub-floor 12 and is characterized by openings 18. 
Three identical plates are used for the assembly of a tripod 10. Referring 
to FIG. 3, one of the three plates, plate 20a, is shown. The plate 20a 
comprises an upper edge 22a and a lower edge 24a. A wall 26a is joined to 
two mirror image leg sections 28a. The depending outer portions of the 
legs 28a are turned to form flanges 30a. The leg sections 28a are 
apertured at 32a. 
As shown in FIGS. 4 and 5, the tripod 10 comprises three assembled plates 
20a, 20b and 20c, together with other components. Prior to assembling the 
tripod 10, a strip of damping material 34 is sandwiched between the leg 
sections 28 of the plates 20a, 20b and 20c. Specifically, the damping 
material 34 is placed between the opposed legs 28a-28b; 28b-28c and 
28c-28a. 
A suitable damping material would be a viscoelastic elastomer such as butyl 
rubber or a commercial thermoplastic damping pad. This material would have 
a dynamic loss modulus of 10.sup.10 Dynes/cm.sup.2 at 100-1000 Hz 
(typically). The damping material is shown as a looped strip. Any 
geometric configuration can be used, parallel strips, sinusoidal, 
circular, etcetera. Also, the damping material need not be in the form of 
a strip. It can be uniform or non-uniform pieces of any geometric 
configuration arrayed between the legs in a uniform or non-uniform 
pattern. 
The plates 20a, 20b and 20c are bolted together as shown by bolts 36. Feet 
38 are secured, such as by welding, to the lower edges 24 of the legs 28. 
Set screws 40 are threaded into the feet 38. 
A base plate 42 is secured to the upper edges 22 of the plates 20, such as 
by welding. The base plate 42 is characterized by a tapped hole 44. A 
rectangular top plate 46, having an aperture 48, is rotatably secured to 
the base plate 42 by a threaded fastener 50, e.g. a flathead screw. 
Friction pads 52 are sandwiched between the top plate 46 and the base 
plate 42. 
In use, when it is known which equipment is to be supported in the 
cleanroom, and more particularly where the point contacts of the equipment 
will be located, openings are formed in the raised floor at these 
locations. Referring to FIGS. 1 and 2, assuming the top plate 46 is a 12" 
square, then 12" openings 18 are formed in the raised floor 16. The feet 
38 of the tripod 10 are set on the sub-floor 12 spanning any knockouts 14. 
The top plate 46 is rotated until it is aligned with the square opening 18 
formed in the raised floor 16 and then fixed or locked into position. The 
set screws 40 are used to locate the top plate 46 in the opening 18. These 
steps are repeated for the total number of tripods required. Then the 
equipment is placed on the support plates of the tripods. 
The foregoing description has been limited to a specific embodiment of the 
invention. It will be apparent, however, that variations and modifications 
can be made to the invention, with the attainment of some or all of the 
advantages of the invention. Therefore, it is the object of the appended 
claims to cover all such variations and modifications as come within the 
true spirit and scope of the invention.