20 Ton Machine Screw Jacks
WJ820, WJ2420, WJ2520, DWJ820, DWJ2420
Joyce 20-ton worm gear machine screw jacks lift and precisely position loads. Upright or inverted, these jacks operate at full capacity in tension or compression and are available in Translating, Keyed for non-rotation and KFTN designs. WJ, single lead jacks are self-locking. DWJ, double lead jacks offer increased travel speed and require a brake or external locking device to hold position.
- 2 1/2” diameter lifting screw
- Available in a variety ratios and leads
- Single lead WJ - .500” lead, ACME 2C
- Double lead DWJ - .375” pitch/ .750” lead, ACME 2C
- Numeric ratio, 100 TPI, .250” lead, ACME 2C
- Screw material – Cold Drawn Steel (CDS)
- Ductile iron housing
- Lifting screw, cold drawn steel (CDS)
- Input shaft (worm), CDS
- Aluminum bronze internal wormgear
- Aluminum bronze Traveling Nut (KFTN)
Sample Part Number:
Click on the part number to reveal additional informaton about jack designs and shaft codes.
|Miniature||1-Ton||2-Ton||2-Ton Reverse Base||3-Ton||5-Ton||10-Ton||15-Ton||20-Ton|
|25-Ton||30-Ton||35-Ton||50-Ton||50-Ton Reverse Base||75-Ton||100-Ton||150-Ton||250-Ton|
Important Note: *Not self-locking, may lower under load. Brake motors or external locking systems are recommended.
D: Double Lead Screw
R: Reverse Base Jack, (only available on 2-ton and 50-ton jacks).
K=Keyed for Non Rotation
* Standard trunnion mounts available on 2-ton through 20-ton jacks.
Machine 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 machine screw jacks. When specified, the closed height of the jack and/or the protection tube length may be increased. When boots are added to machine screw jacks, the closed height of the jack may be increased.
Note: Contact Joyce/Dayton for availability and options.
POTC=0-10V w/2 switches*
POTD=4-20MA w/2 switches*
*Optional IP65 rating available
Encoders and Electronic Liit Switches
ELS2=2 Position Electronic Switch
ELS4=4 Position Electronic Switch
ELS6=6 Position Electronic Switch
Motor for Systems and Direct Drives
- 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||SCRW DIAM (INCH)||THRD PITCH/ LEAD||WORM GEAR RATIO||WORM SHAFT TURNS FOR 1" TRAVEL||TARE TORQUE (INCH LBS.)||STARTING TORQUE (INCH LBS.)||OPERATING TORQUE (INCH LBS.)||EFFICIENCY
RATING % APPROX.
|SCREW TORQUE (INCH LBS.)||BASIC JACK WEIGHT (LBS).||JACK WEIGHT PER INCH TRAVEL (LBS.)|
|WJ820||2 ½||.500 pitch
|8:1||16||40||.075W*||.051W* @ 200 RPM||19.6||.227W*||77||1.9|
|WJ2420||2 ½||.500 pitch
|24:1||48||40||.039W*||.022W* @ 200 RPM||15.4||.227W*||77||1.9|
|WJ2520||2 ½||.250 pitch
|25:1||100||40||.029W*||.016W* @ 200 RPM||9.4||.194W*||77||1.9|
|DWJ820||2 ½||.375 pitch
.750 lead ACME 2C
|8:1||10.67||40||.088W*||.061W* @ 200 RPM||24.5||.272W*||77||1.9|
|DWJ2420||2 ½||.375 pitch
.750 lead ACME 2C
|24:1||32||40||.026W*||.025W* @ 200 RPM||19.3||.272W*||77||1.9|
Important Note: Series DWJ double lead screw jacks are not self-locking. Brake motors or external locking systems are recommended.
(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).
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.