Section 11: Bottom Mounted Stop Block; The Hytork Solution; Basic Stop Block Assembly - Emerson Hytork XL Series Installation, Operation And Maintenance Manual

Section 11: Bottom Mounted Stop Block

November 2022
Section 11:
11.1

The Hytork Solution

On the larger sizes of actuators, the adjustment is obtained by the addition of a simple
stop block that fits under the actuator. The actuator is manufactured with overtravel to
give -3° to +93° of movement and the bottom mounted stop block provides the required
adjustment of 10° at each end of the travel.
11.2

Basic Stop Block Assembly

1.
2.
3.
4.
5.
6.
The basic assembly of the stop block is now complete and ready for fitting to the
actuator/valve package.
20
Bottom Mounted Stop Block
Place the stop block body (refer to Figure 8, [a]) onto a flat clean surface with the
shallow recess on the underside with the two tapped holes facing towards you.
Place a small drop of loctite 222 on each of the four (4) dowel pins (refer to
Figure 8, [b]) and push them, with the points facing upwards, into the location
holes next to the four through holes that are used for fixing the block to the
actuator. The dowel pins must be pushed until they bottom in the location holes
which will leave the points projecting above the face of the block.
Assemble the lock nuts onto the stop bolts (refer to Figure 8, [c]), before screwing
them into the block. Screw the stop bolts into the two tapped holes in the block
(the plain turned ends of the stops go into the tapped holes) until the ends are just
visible in the center recess. If they protrude, they will not allow the stop quadrant
(refer to Figure 8, [d]) to be fitted.
Lightly grease the face of the recess in the block with LS2 grease or any
lithium-based grease. Fit the stop quadrant to the adaptor with the arrowhead
that is cast into the quadrant pointing towards thesingle indent drilled into the
block face. This single indent is on the center line of the block between the stops
and should be nearest to you (refer to Figure 8).
Screw in the right hand stop bolt "B" (refer to Figure 8) until it starts
to move the quadrant; then back off one complete turn and lightly tighten the
lock nut.
Rotate the quadrant until the arrowhead points towards the double indent.
Screw in the left hand stop bolt "A" (refer to Figure 8) until it starts to move the
quadrant then back off one complete turn and lightly tighten the lock nut.
Installation, Operation and Maintenance Manual
MAC050515 EN Rev. 0
Bottom Mounted Stop Block