Specifications


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4000 Series Single-Acting Telescopic Cylinder Product Information

Double-acting telescopic cylinder  Lifting Capacities 

Single-Acting Telescopic Cylinders - 4000 Series
  Specific Operating Pressures
Plunger Diameter (in.)
Cross Sectional Area (Sq. In.)
1,500 PSI (lbs.)
1,800 PSI (lbs.)
2,000 PSI (lbs.)
2,500 PSI (lbs.)

2

3.14

4,710

5,672

6,280

7.850

3

7.06

10,590

12,708

14,120

17,650

4

12.56

18,840

22,608

25,120

31,400

5

19.63

29,445

35,334

39,260

49,075

6

28.27

42,405

50,886

56,540

70,675

7

38.48

57,720

69,264

76,960

Consult Factory

8

50.26

75,390

90,468

100,520

Consult Factory

8-1/4

53.50

80,250

96,300

107,000

Consult Factory

9-1/8

65.40

98,100

117,720

130,800

Consult Factory

9-3/4

74.50

111,750

134,100

149,000

Consult Factory

 

 Double-acting telescopic cylinder Model and Serial Number 

MN Single-Acting Telescopic

 

 The following is an example of Custom Hoists, Inc. model numbers:

Model Number Example for Single-Acting Telescopic

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.

Part number locator

 

 

Double-acting telescopic cylinder Fluid Displacements

Cylinder Size

Fill

Extend

Retract

32

.023

.032

.010

42

.032

.043

.013

43

.015

.032

.011

52

.043

.071

.016

53

.025

.057

.014

54

.015

.044

.013

62

.063

.105

.019

63

.036

.087

.018

64

.025

.073

.016

72

.088

.145

.023

73

.050

.125

.021

74

.035

.106

.019

75

.025

.091

.018

82

.111

.192

.026

83

.068

.169

.025

84

.046

.147

.023

85

.033

.128

.021

86

.025

.112

.020

 


 

Cylinder Size

Fill

Extend

Retract

8 1/4 3

.061

.150

.029

8 1/4 4

0.49

.134

.027

8 1/4 5

0.37

.115

.024

8 1/4 6

.024

.097

.022

92

.153

.251

.034

93

.073

.222

.031

94

.059

.197

.029

95

.046

.174

.026

96

.033

.155

.024

9 3/4 2

.159

.277

.048

9 3/4 3

.079

.240

.040

9 3/4 4

.065

.210

.035

9 3/4 5

.052

.185

.032

9 3/4 6

.039

.163

.029

 


 

Telescopic Fluid

Displacement Formula

To determine fluid displacement (in gallons) to fill a particular cylinder size, multiply desired cylinder stroke and "fill" factor from below chart. For fully extended displacement, multiply desired cylinder stroke and "extend" factor from below chart.

 

Example:
Model No. 85-4402-250
Fill: .033 x 250 = 8.3 gal.
Extend: .128 x 250 = 32.0 gal.

Note: Same formula used for single-acting and double-acting telescopic cylinders.

 

Double-acting telescopic cylinder Cylinder Operation  

Extending Cylinder

To Extend: High pressure oil from the pump is directed by the control valve through port (A)
to fill the cylinder. Any air in the hydraulic system will be trapped in the end of the cylinder (B)
and may be bled off through the bleeder valve (C). It is advisable to bleed air from the cylinder
on initial start up and on a weekly basis thereafter.

As the system pressure rises, the oil pushes on the bottom of the largest plunger (F)
forcing it to move out. The outside diameter or sealing area of the plunger (D)
determines the effective area.

As the plunger extends, the oil trapped between the plunger wall (E) is released through
internal port holes in the plunger. When the largest stage is fully extended, the next largest
will proceed to extend, etc.

To Retract: A single-acting telescopic cylinder must be retracted by gravity or
mechanical means.

 

Double-acting telescopic cylinder Normal Service Items 

Packing, wipers and bushings are considered normal service or replacement items.
These items are subject to contamination from external and internal foreign materials,
many of which are abrasive in nature, causing abnormal wear or damage to the parts,
to the extent replacements are required.

Cylinders may be subject to leaking oil past the seal for various reasons requiring
adjustment of the head/packing nuts. This is considered a normal installation and
field service adjustment to correct the leakage.

Warning!
Before making adjustments or repairs to the cylinder when mounted in the unit,
use strong, heavy, positive supports to hold the body from accidentally lowering which
can cause severe injury or death and/or damage to the unit and cylinder. Place control
valve in the lower position to insure the pressure is relieved in the cylinder. High pressure
can cause severe injury or death and/or damage to the unit and cylinder.

Procedure for adjusting headnuts on telescopic cylinders

A. For leaking cylinders

1. Loosen set screw(s) in headnut of leaking stage(s).

2. Tap headnut lightly around circumference with a hammer.

3. Using a chain wrench, back headnut off one half to one full turn.
\If plunger turns as you are turning the headnut, the plunger will have to be held,
preferably with a strap wrench.

4. Cycle cylinder two or three times to reset vee ring packing.

5.Tighten headnut one half turn farther than it was loosened.

6. Tighten set screw(s).

B. For mis-sequencing cylinders:

1. Loosen set screw in headnut on stage that is sticking.

2. Tap headnut lightly around circumference with a hammer.

3. Using a chain wrench, back off headnut one half turn.

4. Cycle cylinder. If cylinder still mis-stages, turn headnut another half turn.

5. Cycle cylinder. If cylinder still mis-stages, tighten the headnut on the next stage that
is extending. If plunger turns as you are turning the headnut, the plunger will have to be
held, preferably with a strap wrench.

6. Tighten set screw(s).

C.  (a) Instructions for Self-Bleed Type Hydraulic Cylinders

After installation, cycle the cylinder approximately 5 times to remove air.  If erratic operation occurs,
continue to cycle until cycle is smooth.  Cylinder will continue to bleed itself during use. 
Special considerations:
While the typical 5 cycles is usually sufficient; it may take several more cycles to bleed out enough air
to eliminate erratic operation.  Not all systems are the same and considerably more cycles may be needed
upon installation.

If air pressure is being used to aid in cylinder installation such as to raise mounting to attachment position,
it is best to remove air pressure before cycling cylinder.

Older systems may be susceptible to air being induced; make certain that there is no part of the system
that can allow air to be drawn into the system.

Avoid hose routing that will cause air to be trapped.  Large loops in the hose routing will be
areas for air to collect.  Also, it may be more difficult to bleed if the reservoir is far from the cylinder and
positioned very low with respect to the cylinder.

Always allow adequate air space in hydraulic reservoir per system recommendations.

Upon initial installation it may be necessary to allow time for the air to dissipate from the oil in the reservoir.
Check oil level periodically to avoid reservoir being drained during cylinder cycle.


C.  (b) Bleeding air from Single-Acting Telescopic Cylinders

1. Empty the dump body of any material.

2. Remove the cover plate from the doghouse of the dump body to access the
cylinder bleeder valve.

3. Fully extend the cylinder, raising the empty dump bed.

4. Lower the dump bed to within one foot from the frame.

5. Turn the bleeder valve in a counterclockwise direction. This opens the valve and
allows the air to escape from the cylinder.

6. When a steady stream of oil comes from the bleeder, turn the valve in a clockwise
direction until it is closed.

NOTE: For consistent operation of telescopic cylinders, it is advisable to bleed the
air from the cylinder weekly.
If these procedures fail to correct the problem, contact the factory or an authorized
service center for further instructions.

 

Double-acting telescopic cylinder 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 dump body or trailer 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, free of any lateral loading of the plungers.
    Misalignment of the top or bottom mountings, or mounting pins too tight,
    may cause scoring of the plungers, leaking, or improper sequencing which
    could cause the unit to upset.

  • 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 dump body or trailer.

  • The operator should stay at the controls during the entire dumping operation.
    If the body starts to lean, the operator should immediately lower the
    dump body or trailer. It is important to slowly position the cylinder control valve
    into the hold position to avoid subjecting the cylinder to high pressure.

  • Do not overload the unit. The load must be distributed evenly during loading
    or unloading to avoid rollover and lateral tilt. Loads stuck while the cylinder is
    partially or completely extended increases the hazard of rollover and lateral tilt.
    Lower the dump body or trailer entirely with the cylinder control valve partially
    open (avoid lowering the dump body or trailer with the cylinder control
    valve completely open). Then unload the dump body or trailer manually or
    with an alternative mechanical aid.

WARNING!
Shock pressure can cause severe injury or death
and/or damage to the unit and cylinder.

  • Do not use the cylinder to loosen loads stuck in the dump body or trailer.
    Lower the dump body or trailer entirely with the cylinder control valve partially open
    (avoid lowering the dump body or trailer with the cylinder control valve completely open).
    Then unload the dump body or trailer manually or with an alternative mechanical aid.

  • Do not move the truck and jam the brakes while the cylinder is partially or
    fully extended to loosen loads stuck in the dump body or trailer. Lower the
    dump body or trailer entirely with the cylinder control valve partially open
    (avoid lowering the dump body or trailer with the cylinder control valve completely open).
    Then unload the dump body or trailer manually or with an alternative mechanical aid.

  • Do not move the truck until the dump body or trailer is lowered completely.

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.

WARNING!

Worn or damaged hydraulic hoses can cause severe injury or death
and/or damage to the unit and cylinder.

  • Hydraulic hoses should be checked regularly and replaced if worn out or damaged.

NOTICE!
Do not drive the unit while the P.T.O. or hydraulic pump is engaged.
The hydraulic oil should be checked and changed regularly to avoid contamination
leading to internal cylinder damage. A damp to light film of oil on each plunger
indicates a good cylinder operation. A small accumulation of oil may be noticed on
the plunger at the head nuts after many cycles. This should not be mistaken for
packing leakage. It is advisable to bleed air from the cylinder weekly to free entrapped air.
This will result in a smoother operation. Grease the pin mountings regularly.





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