. Science of railways . Fig. Screw Jack. Fig. 2. Joyce Double Movement Screw Jack. for instant use in case of break-down on the road, andunless the screw portion is properly protected, theysoon rust and become unfit for service. Fig. 2 shows a double movement screw jack, whiclilifts twice as rapidly as a single s^rew, and, it isclaimed, requires no more power on account of therebeing no friction under the cap, as in the case of thelatter. 658 LOCOMOTIVE APPLIANCES. The rapid moving jack shown in Fig. 3 is so calledbecause, when the load is off, it can be raised immedi-ately to any de
. Science of railways . Fig. Screw Jack. Fig. 2. Joyce Double Movement Screw Jack. for instant use in case of break-down on the road, andunless the screw portion is properly protected, theysoon rust and become unfit for service. Fig. 2 shows a double movement screw jack, whiclilifts twice as rapidly as a single s^rew, and, it isclaimed, requires no more power on account of therebeing no friction under the cap, as in the case of thelatter. 658 LOCOMOTIVE APPLIANCES. The rapid moving jack shown in Fig. 3 is so calledbecause, when the load is off, it can be raised immedi-ately to any desired point, and when up can be asquickly let down, thus saving the tedious operation ofturning the screw up and down without load. Thetwo segmental nuts are supported on steel pinsmoving in angular slots, so as to allow them to movein and out of gear. To raise the screw to any desiredheight ^or work, it is only necessary to lift it by taking.
Size: 1154px × 2165px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, bookdecade1910, bookidscienceofrailway14kirk
