Design of a universal portable electric drill . the armature pinion v/hich screws into the shaft. The inner race of the upper bearing is clamped with a screw and washer in the end of the shaft. The dimensions and capacitiesof these bearings are as follows: Upper Armature BearingNo. 300 Outside diameter, 35 m mBore, 10 m mWidth, 11 m mBalls , 9 inch Radial load capacity, 100 pounds,at 2000 RPM - the maximumspeed at which this bearingis rated by 43 Lower Armature BearingNo. 301 Outside diameter, 37 m m Bore , 12 m m Width, 12 m m Balls, 10 i inch Radial load capacity, 110 poundsat
Design of a universal portable electric drill . the armature pinion v/hich screws into the shaft. The inner race of the upper bearing is clamped with a screw and washer in the end of the shaft. The dimensions and capacitiesof these bearings are as follows: Upper Armature BearingNo. 300 Outside diameter, 35 m mBore, 10 m mWidth, 11 m mBalls , 9 inch Radial load capacity, 100 pounds,at 2000 RPM - the maximumspeed at which this bearingis rated by 43 Lower Armature BearingNo. 301 Outside diameter, 37 m m Bore , 12 m m Width, 12 m m Balls, 10 i inch Radial load capacity, 110 poundsat 2000 RPM - the maximumspeed at v;hich this bearingis rated by the manufacturer The radial load on these bearings is not over 20^ of the ratedcapacity at normal load but experience has taught that the speedat which they operate in this type of machine necessitates a verygenerous factor of safety. The bearings on the compound shaft and spindle are of theplain bronze type. The bearing loads throughout the machine canbe analyzed as in Figure » 44 The bearing loads are as follows: Upper -^^fmature Bearing, 1 lb. Lower -^rmature Bearing, lbs. Upper Compound Bearing, lbs. Lower Corapounn Bearing, lbs. Spindle Bearing, 350 lbs. The rubbing areas, pressures and rubbing velocities are asfollows; Upper Compound Bearing, 7/l6 x 11/16 area, .3 aq. , lbs. per gq, i^i^Rubbing velocity, 176 ft. per min. Lower Compound Bearing, 7/l6 x 1 area, .438 sq. , 87 lbs. per sq. velocity, 176 ft. per min. Spindle Bearing 15/16 x 2-1/8 long. Projected area, 2 sq, in. Pressure, 175 lbs. per sq. in. Rubbing velocity, 85 ft. per will be noticed that with grease lubrication these bearingpressures are very liberal. Experience has shown that it payswell to be liberal in this respect. The use of smaller bearingswould shorten the life of the tool with practically no reductionin cost. —-] 45 The thrust bearing ia mo
Size: 2246px × 1113px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttheses, bookyear1920
