industrial acids, chemicals, solvents, and gases. During the assembly pro- 

 cedure of the motor units, several grades of those anaerobic adhesives and 

 sealants were used as sealants, fasteners, and locking materials. 



2.2.6 Bearings 



By using Kaydon Reali-Slim ball bearings, the outside housing diameters 

 could be minimized because of the thin cross section of these bearings. The 

 Type X bearing was chosen because of its ability to resist radial thrust and 

 moment loads in any combination. A pair of FAG Angular Contact ball bearings 

 holds the motor shaft in position. The chosen bearing (7000-series) is de- 

 signed for medium to high speeds, and with a contact angle of 25 degrees it 

 can carry heavy and radial loads combined with medium thrust loads in one 

 direction. Because of the thin cross section of the bearing, the supporting 

 housing parts could be minimized. 



2.3 STRUCTURE ELEMENTS 



The motor units which drive the manipulator joints are connected to the 

 arm structure elements by lightweight laminated glass-fiber parts with epoxy. 

 resins. A washcoat 5 to 10 mils thick prevents intrusion of water. No pig- 

 ments have been used in the layup process to allow easy visual inspection of 

 the parts. The laminate design is capable of withstanding hydrostatic pres- 

 sure of 1000 psi . The structure part which connects shoulder and elbow joints 



3 

 is filled with 32-1 b/ft syntactic foam to provide buoyancy underwater. Use 



of glass-fiber-based epoxy resin has the following advantages: 



- Light weight (has 30% weight saving over aluminum). 



- Insulated (no electrolytic reaction with aluminum parts). 



- Noncorrosivity. 



- Easily manufactured. 



- High flexural strength (65 000 psi min). 



15 



