# US 4,395,503 A · Antenna grout replacement system

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- Number: US 4,395,503 A
- Document ID: US4395503A
- Status: Granted
- Kind: A
- Application number: 06/233,271
- Filed: 1981-02-10
- Granted: 1983-07-26
- Earliest claimed: 1981-02-10
- Assignees: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
- Inventors: Charles E. McClung
- Web page: https://patentgrep.com/patent/US4395503A

## CPC

- H01Q 3/08: for varying two co-ordinates of the orientation
- C04B 26/14: Polyepoxides
- C08K 3/36: Silica
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

An epoxy grout suitable for use in mounting and positioning bearing runner plates used in hydrostatic bearing assemblies for rotatably mounting large radio telescope structures to stationary support pedestals. The epoxy grout may be used in original mountings or may be used as part of a replacement system for repairing cavities in existing grout resulting from grout deterioration. The epoxy grout has a relatively short work life and cure time even in the presence of hydraulic oil. The epoxy grout cures without shrinking or sagging to form a grout which is sufficiently strong and durable to provide a grout especially well-suited for use under the high pressure loading and close tolerance requirements of large hydrostatic bearing assemblies.

## Claims

### Claim 1

A fast-curing, non-sagging, oil-compatible, support grout consisting essentially of between 10-20% by weight of epoxy resin; 80-90% by weight of inert, inorganic filler having a mesh size below 10, less than 5% by weight of colloidal silica thickening agent and a fast curing agent for said epoxy resin in an amount effective to cure said epoxy resin in less than one minute to a rigid, cured state which is dimensionally stable under high loads and high pressures.

### Claim 2 (depends on 1)

A support grout according to claim 1 in which the curing agent is triethylene tetramine.

### Claim 3 (depends on 1)

A grout according to claim 1 in which the inert, inorganic filler is selected from graded sand or pebbles.

### Claim 4 (depends on 3)

A grout according to claim 3 in which the cured grout has a compressive strength of at least about 22,000 psi.

### Claim 5 (depends on 1)

A support grout in accordance with claim 1 wherein said grout consists of between about 14-17% by weight epoxy resin, less than 2% by weight colloidal silica and between about 83-86% by weight inert filler.

### Claim 6 (depends on 5)

A support grout according to claim 5 wherein said epoxy resin is a Bis-Phenol A epoxy resin and said inert filler is sand aggregate.

### Claim 7 (depends on 6)

A support grout according to claim 6 wherein said curing agent is an amine.

### Claim 8 (depends on 6)

A support grout according to claim 6 wherein, said epoxy resin has an equivalent weight of between about 175 and 200 and has a viscosity of between about 10,000 and 18,000 cps.

### Claim 9 (depends on 8)

A support grout according to claim 8 consisting essentially of about 82.1 percent by weight inert filler, 2.00 percent by weight colloidal silica, 14.10 percent by weight epoxy resin, and 1.80 percent by weight curing agent.