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| Double-Acting Telescopic Cylinder Product Information |
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 Specifications |
# of Stages |
3 |
Largest Moving Stage Diameter |
6" |
Stroke (A) |
118.13" |
Closed (B) |
58.50" |
Ext. (C) |
176.63" |
Base Mount (D) |
3.00" |
Base Mount (E) |
2.56" |
Plunger Mount (F) |
3.94" |
Plunger Mount (G) |
2.56" |
Dry Wt. (lbs.) |
330 | |
| Lifting Capacities |
| Double-Acting Telescopic Cylinders |
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Specific Operating Pressures |
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Bore (Piston)
Diameter (in.) |
Cross Sectional Area (Sq. In.) |
Plunger
Diameter (in.) |
Cross Sectional Area (Sq. In.) |
1,500 PSI
(lbs.) |
1,800 PSI
(lbs.) |
2,000 PSI
(lbs.) |
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2-1/2 |
4.90 |
2 |
3.14 |
7,350 |
8,820 |
9,800 |
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3-1/2 |
9.62 |
3 |
7.06 |
14,340 |
17,316 |
19,240 |
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4-1/2 |
15.90 |
4 |
12.56 |
23,850 |
28,620 |
31,800 |
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5-1/2 |
23.75 |
5 |
19.63 |
35,625 |
42,750 |
47,500 |
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6-1/2 |
33.18 |
6 |
28.27 |
49,770 |
59,724 |
66,360 |
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7-1/2 |
44.17 |
7 |
38.48 |
66,255 |
79,506 |
88,340 |
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8-1/2 |
56.74 |
8 |
50.26 |
85,110 |
102,132 |
113,480 |
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9-3/4 |
74.50 |
9-1/8 |
65.39 |
111,170 |
134,100 |
149,000 |
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10-1/2 |
86.59 |
9-3/4 |
74.50 |
129,885 |
155,862 |
173,180 | |
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| Model and Serial Number |
MN Double-Acting Telescopic |
The following is an example of Custom Hoists, Inc. model numbers:
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Locator |
Custom Hoists, Inc. model numbers and serial numbers are either stamped on the O.D. of the cylinder body (manufactured prior to 8-99) or stamped on a metal plate which is welded to the O.D. of the cylinder body (manufactured after 8-99). Using these model numbers will eliminate misunderstandings when placing orders or requesting information.
Model number and serial number stamped in body or on a name plate.
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| Cylinder Operation |
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Extending
To Extend:
High pressure oil is directed by the control valve into extend port (A). The oil passes through an inner (transfer) tube in the smallest plunger to the base of the cylinder. The pressure acts on the effective area of the largest piston (F) and extends all stages to the first plunger stop. The next stage then begins to extend. The effective area of each stage is figured from the inside diameter of the next largest stage. Each stage extends in its turn to the plunger stop.
Oil trapped between the plungers escapes through internal port holes (C) in each plunger and returns to tank through retract port (B).
Retracting
To Retract:
High pressure oil is directed by the control valve into retract port (B). The pressure is applied to the effective area of the smallest plunger (D) which retracts first. Each stage from the smallest to the largest retracts in its turn. The effective area for retracting each stage is the area of the plunger (D). Oil inside the cylinder is forced out of extend port (A). Because of the area differential between the retract side and extend side the flow into retract port (B) must be multiplied by this differential to determine the flow out of port. It may be necessary to install a dump-to-tank valve to speed up the retracting cycle. |
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| Safety Precautions |
WARNING!
Rollover or lateral tilt can cause severe injury or death and/or damage to the unit and cylinder.
- The hydraulic cylinder will not prevent the unit from rollover or lateral tilt. The cylinder is strictly a lifting device and is not a structural member of the unit. Cylinders are not to be used as a means of stabilizing the unit.
- The hydraulic cylinder mounted in the unit should be free to find its own trajectory line of extension and retraction so as not to cause improper sequencing and excessive wear to the plungers and internal components. Misalignment could cause the unit to upset. On longer stroke cylinders mounted horizontally, supports should be added to the center of the extended cylinder to increase the column strength of the cylinder.
- The hydraulic cylinder will not withstand lateral pressure when the unit is leaning. Only activate the cylinder when the tractor and trailer are in a straight line (not jack-knifed). Do not activate the cylinder while on unlevel or soft ground, or during heavy crosswinds. Doing so may cause the unit to upset.
- Do not activate the cylinder while personnel or equipment are alongside or behind the unit.
- On roll-off units, if the container is not loaded evenly, the lift cylinder(s) may mis-stage which could cause the unit to upset and/or damage the cylinder when the plungers attempt to correct themselves.
- On roll-off units, lower the container with the control valve partially open (avoid lowering the container with the control valve completely open) to prevent pressure build-up in the reeving cylinders as gravity pulls the container to the ground.
WARNING!
Shock pressure can cause severe injury or death and/or damage to the unit and cylinder.
- Do not extend the cylinder until it has been fully retracted. A partially extended cylinder with pressure relieved may drift out of position. When the cylinder is later extended, the out of position plunger will reposition rapidly and possibly cause high pressure trapped oil on the retract side of the cylinder. On roll-off units, do not pull a container onto the hoist until the lift cylinder(s) are completely extended.
- On roll-off units, care must be taken if a unit is moved with the lift cylinders extended. Avoid sudden stops or jolts.
- Check the cylinder operation to ensure the plungers extend in sequence with the largest diameter plunger moving first, then the next largest, etc. When retracting, the smallest plunger should move first, then the next smallest, etc. Mis-staging could cause the unit to upset and/or damage the cylinder due to excessive pressure build-up.
WARNING!
Over pressurizing the cylinder can cause severe injury or death and/or damage to the unit and cylinder.
- Do not operate the cylinder at pressures greater than 2000 P.S.I. unless otherwise approved in writing by Custom Hoists, Inc.
- Hydraulic hoses should be checked regularly and replaced if worn out or damaged.
NOTICE!
Do not operate a packer/ejector cylinder with a mis-aligned blade. This can cause excessive lateral loading to the cylinder which could cause internal damage.
If the hydraulic system uses quick disconnects or holding/lock type valves, make sure they are properly connected. If not, oil may become trapped in the cylinder which could cause internal damage.
A double-acting telescopic cylinder normally requires at least 15 G.P.M. oil flow to retract properly. Make sure the hydraulic pump is developing the required flow.
Most double-acting telescopic cylinders will bleed themselves of air. On a new cylinder installation, cycle the cylinder approximately ten times to the complete extend and retract positions with no load against it to remove the entrapped air.
The hydraulic oil should be checked and changed regularly to avoid contamination leading to internal cylinder damage.
Grease the pin mountings regularly. |
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