20 Ton Ball Screw Jacks
Joyce 20-ton ball screw worm gear jacks lift and precisely position loads. Upright or inverted, these jacks operate at full capacity in tension or in compression and are available in Translating and KFTN designs. Standard WB820, and WB2420 jacks are highly efficient and require a brake or other external locking device to hold position.
WB820 jacks feature:
- 2 1/4” diameter lifting screw
- Standard lead, 0.5”
- Available in several internal gear set ratios
- Ductile iron housing
- Steel protection tube
- Ball screw, alloy steel
- Input shaft (worm), 4140 CDS
Sample Part Number:
Click on the part number to reveal additional informaton about jack designs and shaft codes.
|1-Ton Standard||2-Ton Standard||2-Ton Reverse Base Standard||5-Ton Standard||10-Ton Standard||10-Ton Heavy Duty||20-Ton Standard||30-Ton Standard||50-Ton Standard|
|1-Ton Heavy Duty||2-Ton High Lead||2-Ton Reverse Base High Lead||5-Ton High Lead||10-Ton Standard High Lead||10-Ton Heavy Duty High Lead||50-Ton Reverse Base|
Important Note: *Not self-locking, may lower under load. Brake motors or external locking systems are required.
H: indicates High lead (2-ton, 5-ton and 10-ton only).
R: Reverse Base Jack (2-ton and 50-ton only).
K=Keyed for Non Rotation**
*Standard trunnion mounts available on 2-ton through 20-ton jacks.
**Keyed for non-rotation is not a standard option. Contact Joyce/Dayton with your requirements.
Ball Screw Jack Rise
Rise is travel expressed in inches and not the actual screw length.
Left Side Shaft Code
Right Side Shaft Code
Optional Shaft Codes
Screw Stops and Boots
Screw stops are optional on ball screw jacks. When specified, the closed height of the jack and/or the protection tube length may be increased. When boots are added to ball screw jacks, the closed height of the jack may be increased.
POTC=0-10V w/2 switches*
POTD=4-20MA w/2 switches*
*Optional IP65 rating available
Encoders and Electronic Limit Switches
ELS2=2 Position Electronic Switch
ELS4=4 Position Electronic Switch
ELS6=6 Position Electronic Switch
Motor for Systems and Direct Drive
- All standard motors are 3-phase, 208-230/460 VAC or 230/460 VAC. Other motor options are available. Specify the appropriate motor size from the chart on the right.
- Refer to the "Additional Options" chart on the preceding page as needed.
- Brake motors (M2) are recommended for jacks that are not self-locking, and jacks with double lead screws.
- If the motor frequency will be varied to provide a "soft" start an inverter duty motor may be required.
MMA A (Motor code from chart above)
Standard motor adapters are aluminum
Mechanical Limit Switches
LA (Models) 1(Number of DPDT Switches) 3(Available Positions)
Number of DPDT Switches
NOTE: Will always be 0 for LS7 models
|LS8-402||LA||Left Side Shaft Options|
|LS9-503||LD||Right Side Shaft Options|
These positions are not standard. Contact Joyce/Dayton with your requirements.
- X=Standard Jack, no additional options
- S=Additional Specification Required (comment as necessary)
- A=Split Nut
- A90=A90 Design
- A95=A95 Design
- B=Protective Boot
- D=Dual Protective Boot
- F1=Do Not Paint
- F2=Epoxy Paint
- F3=Outdoor Paint Process
- M1=Less Motor
- M2=Brake Motor
- M3=Single Phase Motor (120VAC)
- M4=50Hz Motor
- H1=High Temperature Operation
- H2=Food Grade
- Specify as many options as needed
|Model||Capacity||Screw Diameter (inches)||Thread Pitch/Lead||Worm Gear Ratio||Worm Shaft Turns for 1" Travel||Tare Torque (Inches Lbs.)||Starting Torque (Inches Lbs.)||Operating Torque (Inches Lbs.)||Efficiency Rating % Approx||Screw Torque (Inches Lbs.)||Worm Holding (Inch Lbs.)||Ball Nut Life at Rated Load (Inch Screw Travel x 1000)||Basic Jack Weight (Lbs.)||Jack Weight
per Inch Travel(Lbs.)
|WB820||20 ton||2 1/4||0.5||8:1||16||40||.024W*||.020W* @
|WB2420||20 ton||2 1/4||0.5||24:1||48||40||.012W*||.009W* @
Important Note: Ball Screw Jacks are not self-locking. Brake motors or external locking systems are required.
(R): Reverse Base Jack.
*W: Load in pounds.
Tare Torque: Initial torque to overcome seal and normal assembly drag. (This value must be added to starting torque or operating torque values.)
Starting Torque: Torque value required to start moving a given load (dissipates to operating torque values once the load begins moving).
Operating Torque: Torque required to continuously raise a given load at the input RPM listed. NOTE: If your actual input RPM is 20% higher or lower than the listed RPM, please refer to our JAX program to determine actual torque values at your RPM.
Screw Torque: Torque required to resist screw rotation (Translating Design Jacks) and traveling nut rotation (Keyed for Traveling Nut Design Jacks).
Worm Holding Torque: Torque required to prevent input shaft (worm) from backdriving.
Lead: The distance traveled axially in one rotation of the lifting screw.
Pitch: The distance from a point on a screw thread to a corresponding point on the next thread, measured axially.