Joyce worm gear machine screw jacks lift and precisely position loads (250 pounds to 250 tons). Upright or inverted jacks operate at full capacity in tension or compression. WJ and RWJ, single lead jacks are self-locking. DWJ and DRWJ, double lead jacks offer increased travel speed and require a brake or external locking device to hold position.
- Alloy steel input shafts
- Aluminum bronze wormgears
- Tapered or ball thrust bearings provide rugged reliability
- Double input shafts standard
- Protective boots available
- Anti-backlash devices available
- Customized mechanical jacks can be made to your specifications
- Custom finishes available
Parts list and exploded views are included in the O&M Manual. The serial number is attached to the product housing.
Boots and special finishes are available for Joyce Screw jacks. Choose from a variety of boot materials and designs for the jacks you select (translating, keyed, or KFTN). Joyce offers premium finishes, outdoor paint process, and custom finishes to meet your specifications. We have a hassle-free process for delivering what you need.
What you need to know to specify screw jacks in industrial application.
Jacks are rated based on their static thrust capacity from 250-pounds to 250-tons. But the selection of the best jack for the application requires further consideration.
- When jacks are loaded in compression one must consider the load carrying capacity of the lifting screw (column load). How high do you need to lift the load? Choose a jack whose lifting screw is stout enough to handle the load at full rise.
- Consider the travel speed of the DYNAMIC load. The speed at which the load will be moved is a limiting factor. How fast do you need to move the load? Sometimes double lead machine screw jacks or ball screw jacks are a better choice in a given application.
- How frequently will the jack need to move the load? Remember that heat builds up between the machine screw and nut during normal operation. Duty cycles for machine screw jacks must include periods of rest to dissipate that heat.
Which jack design is best for your application? Once loads, duty cycles, and travel speeds are established, designers must select which of the three jack design to use.
- Translating Design Jacks are most often selected. With this design, a driven input worm acts on an internal worm gear causing the lifting screw to extend or retract. Operation requires that rotation of the lifting screw be prevented. This rotation it restrained whenever two or more jacks are tied to the same load.
- Keyed Design Jacks are used any time rotation of the lifting screw is not restrained. For instance, when you must lift the jack to meet a load. This is how they work: A key, fixed to the jack housing and inserted into a keyway milled into the length of the lifting screw forces the lifting screw to translate without rotating.
- Keyed For Travelign Nut Design Jacks (KFTN) are another option. These jacks have a fixed length lifting screw that rotates. Loads are attached to a flanged “traveling” nut that translates up and down the length of the rotating screw. This type of jack is ideal for applications that cannot accommodate a screw protection tube or that require a flush mount
Take the work out of using screw jacks in systems
Tell us what you need or use our exclusive JAX® Online software (it’s free). We will put together complete systems with single or multiple screw jacks for you. The software is great because it calculates motor horsepower and shaft diameters and torques. Their are several common arrangements, but you can design your own.
Look for our next generation JAX® Online browser-based software soon.
Where are worm gear machine screw jacks used?
Worm gear machine screw jacks are the workhorses of the lifting industry, available in static capacities up to 250-tons. They are commonly used to lift, hold, and position loads. Examples include: Platform lifts, Damper adjustments, Ergonomic lifts, Maintenance lifts, Roll adjustments, Earth Station Antennas, Drilling equipment, Solar Trackers, Conveyor adjustments, Packaging equipment, Gate adjustments, Dam adjustment, and Mine door openers.
| MODEL | CPTY | 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.) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| WJ250 | 250 lbs. | 1/2 | .125 pitch STUB ACME |
5:1 | 40 | 1 | .025W* | .018W* @ 500 RPM | 23.0 | .050W* | 1.2 | 0.1 |
| WJ500 | 500 lbs. | 5/8 | .125 pitch/.250 lead STUB ACME |
5:1 | 20 | 1 | .041W* | .030W* @ 500 RPM | 27.2 | .079W* | 1.3 | 0.1 |
| WJ1000 | 1,000 lbs. | 5/8 | .125 pitch STUB ACME |
5:1 | 40 | 1 | .030W* | .021W* @ 500 RPM | 19.9 | .059W* | 1.3 | 0.1 |
| WJ51 | 1 ton | 3/4 | .200 pitch ACME 2C |
5:1 | 25 | 3 | .038W* | .026W* @ 500 RPM | 25 | .075W* | 6 | 0.3 |
| WJ201 | 1 ton | 3/4 | .200 pitch ACME 2C |
20:1 | 100 | 3 | .017W* | .009W* @ 500 RPM | 15.9 | .075W* | 6 | 0.3 |
| (R)WJT62 | 2 ton | 1 | .250 pitch ACME 2C |
6:1 | 24 | 4 | .041W* | .028W* @ 500 RPM | 24.2 | .098W* | 15 | 0.3 |
| (R)WJT122 | 2 ton | 1 | .250 pitch ACME 2C |
12:1 | 48 | 4 | .025W* | .015W* @ 500 RPM | 22.0 | .098W* | 15 | 0.3 |
| (R)WJT242 | 2 ton | 1 | .250 pitch ACME 2C |
24:1 | 96 | 4 | .018W* | .009W* @ 500 RPM | 18.3 | .098W* | 15 | 0.3 |
| (R)WJT252 | 2 ton | 1 | .250 pitch ACME 2C |
25:1 | 100 | 4 | .015W* | .0085W* @ 500 RPM | 17.0 | .098W* | 15 | 0.3 |
| D(R)WJ62 | 2 ton | 1 | .250 pitch .500 lead ACME 2C |
6:1 | 12 | 4 | .057W* | .039W* @ 500 RPM | 33.7 | .139W* | 15 | 0.3 |
| D(R)WJ122 | 2 ton | 1 | .250 pitch .500 lead ACME 2C |
12:1 | 24 | 4 | .035W* | .022W* @ 500 RPM | 30.5 | .139W* | 15 | 0.3 |
| D(R)WJ242 | 2 ton | 1 | .250 pitch .500 lead ACME 2C |
24:1 | 48 | 4 | .025W* | .013W* @ 500 RPM | 25.4 | .139W* | 15 | 0.3 |
| WJ63 | 3 ton | 1 | .250 pitch ACME 2C |
6:1 | 24 | 6 | .040W* | .029W* @ 500 RPM | 24.3 | .098W* | 17 | 0.4 |
| WJ123 | 3 ton | 1 | .250 pitch ACME 2C |
12:1 | 48 | 6 | .025W* | .016W* @ 500 RPM | 22.2 | .098W* | 17 | 0.4 |
| WJ243 | 3 ton | 1 | .250 pitch ACME 2C |
24:1 | 96 | 6 | .017W* | .009W* @ 500 RPM | 18.5 | .098W* | 17 | 0.4 |
| WJ253 | 3 ton | 1 | .250 pitch ACME 2C |
25:1 | 100 | 6 | .0155W* | .009W* @ 500 RPM | 17.8 | .098W* | 17 | 0.4 |
| DWJ63 | 3 ton | 1 | .250 pitch .500 lead ACME 2C |
6:1 | 12 | 6 | .055W* | .041W* @ 500 RPM | 33.8 | .139W* | 17 | 0.4 |
| DWJ123 | 3 ton | 1 | .250 pitch .500 lead ACME 2C |
12:1 | 24 | 6 | .034W* | .022W* @ 500 RPM | 30.7 | .139W* | 17 | 0.4 |
| DWJ243 | 3 ton | 1 | .250 pitch .500 lead ACME 2C |
24:1 | 48 | 6 | .024W* | .013W* @ 500 RPM | 25.6 | .139W* | 17 | 0.4 |
| WJT65 | 5 ton | 1 ½ | .375 pitch STUB ACME |
6:1 | 16 | 10 | .065W* | .044W* @ 300 RPM | 23.0 | .151W* | 32 | 0.7 |
| WJT125 | 5 ton | 1 ½ | .375 pitch STUB ACME |
12:1 | 32 | 10 | .041W* | .025W* @ 300 RPM | 20.6 | .151W* | 32 | 0.7 |
| WJT245 | 5 ton | 1 ½ | .375 pitch STUB ACME |
24:1 | 64 | 10 | .029W* | .015W* @ 300 RPM | 16.7 | .151W* | 32 | 0.7 |
| WJT255 | 5 ton | 1 ½ | .250 pitch ACME 2C |
25:1 | 100 | 10 | .022W* | .011W* @ 300 RPM | 13.4 | .131W* | 32 | 0.7 |
| DWJ65 | 5 ton | 1 ½ | .250 pitch .500 lead ACME 2C |
6:1 | 12 | 10 | .072W* | .050W* @ 300 RPM | 26.8 | .171W* | 32 | 0.7 |
| DWJ125 | 5 ton | 1 ½ | .250 pitch .500 lead ACME 2C |
12:1 | 24 | 10 | .045W* | .028W* @ 300 RPM | 23.9 | .171W* | 32 | 0.7 |
| DWJ245 | 5 ton | 1 ½ | .250 pitch .500 lead ACME 2C |
24:1 | 48 | 10 | .033W* | .017W* @ 300 RPM | 19.6 | .171W* | 32 | 0.7 |
| WJ810 | 10 ton | 2 | .500 pitch ACME 2C |
8:1 | 16 | 20 | .061W* | .043W* @ 200 RPM | 23.1 | .195W* | 43 | 1.3 |
| WJ2410 | 10 ton | 2 | .500 pitch ACME 2C |
24:1 | 48 | 20 | .030W* | .018W* @ 200 RPM | 18.8 | .195W* | 43 | 1.3 |
| WJ2510 | 10 ton | 2 | .250 pitch ACME 2C |
25:1 | 100 | 20 | .024W* | .014W* @ 200 RPM | 11.3 | .161W* | 43 | 1.3 |
| DWJ810 | 10 ton | 2 | .333 pitch .666 lead ACME 2C |
8:1 | 12 | 20 | .070W* | .062W* @ 200 RPM | 31.9 | .228W* | 43 | 1.3 |
| DWJ2410 | 10 ton | 2 | .333 pitch .666 lead ACME 2C |
24:1 | 36 | 20 | .035W* | .026W* @ 200 RPM | 25.9 | .228W* | 43 | 1.3 |
| WJ815 | 15 ton | 2 ¼ | .500 pitch ACME 2C |
8:1 | 16 | 30 | .069W* | .047W* @ 200 RPM | 21.1 | .210W* | 59 | 1.4 |
| WJ2415 | 15 ton | 2 ¼ | .500 pitch ACME 2C |
24:1 | 48 | 30 | .036W* | .020W* @ 200 RPM | 16.6 | .210W* | 59 | 1.4 |
| WJ2515 | 15 ton | 2 ¼ | .250 pitch ACME 2C |
25:1 | 100 | 30 | .026W* | .015W* @ 200 RPM | 10.2 | .178W* | 59 | 1.4 |
| DWJ815 | 15 ton | 2 ¼ | .333 pitch .666 lead ACME 2C |
8:1 | 12 | 30 | .079W* | .058W* @ 200 RPM | 34.4 | .244W* | 59 | 1.4 |
| DWJ2415 | 15 ton | 2 ¼ | .333 pitch .666 lead ACME 2C |
24:1 | 36 | 30 | .041W* | .025W* @ 200 RPM | 27.0 | .244W* | 59 | 1.4 |
| WJ820 | 20 ton | 2 ½ | .500 pitch ACME 2C |
8:1 | 16 | 40 | .075W* | .051W* @ 200 RPM | 19.6 | .227W* | 77 | 1.9 |
| WJ2420 | 20 ton | 2 ½ | .500 pitch ACME 2C |
24:1 | 48 | 40 | .039W* | .022W* @ 200 RPM | 15.4 | .227W* | 77 | 1.9 |
| WJ2520 | 20 ton | 2 ½ | .250 pitch ACME 2C |
25:1 | 100 | 40 | .029W* | .016W* @ 200 RPM | 9.4 | .194W* | 77 | 1.9 |
| DWJ820 | 20 ton | 2 ½ | .375 pitch .750 lead ACME 2C |
8:1 | 10.67 | 40 | .088W* | .061W* @ 200 RPM | 24.5 | .272W* | 77 | 1.9 |
| DWJ2420 | 20 ton | 2 ½ | .375 pitch .750 lead ACME 2C |
24:1 | 32 | 40 | .046W* | .026W* @ 200 RPM | 19.3 | .272W* | 77 | 1.9 |
| WJ1125 | 25 ton | 3 ⅜ | .666 pitch STUB ACME |
11:1 | 16 | 50 | .088W* | .055W* @ 200 RPM | 18.3 | .313W* | 164 | 3.1 |
| WJ3225 | 25 ton | 3 ⅜ | .666 pitch STUB ACME |
32:1 | 48 | 50 | .053W* | .025W* @ 200 RPM | 13.5 | .313W* | 164 | 3.1 |
| DWJ1125 | 25 ton | 3 ⅜ | .562 pitch 1.125 lead ACME 2C |
11:1 | 9.5 | 50 | .106W* | .067W* @ 200 RPM | 25.1 | .384W* | 164 | 3.1 |
| DWJ3225 | 25 ton | 3 ⅜ | .562 pitch 1.125 lead ACME 2C |
32:1 | 28.5 | 50 | .063W* | .030W* @ 200 RPM | 18.6 | .384W* | 164 | 3.1 |
| WJ1130 | 30 ton | 3 ½ | .666 pitch ACME 2C |
11:1 | 16 | 60 | .088W* | .055W* @ 200 RPM | 18.3 | .313W* | 164 | 3.0 |
| WJ3230 | 30 ton | 3 ½ | .666 pitch ACME 2C |
32:1 | 48 | 60 | .052W* | .025W* @ 200 RPM | 13.5 | .313W* | 164 | 3.0 |
| DWJ1130 | 30 ton | 3 ½ | .5625 pitch 1.125 lead ACME 2C |
11:1 | 9.5 | 60 | .107W* | .067W* @ 200 RPM | 25.1 | .384W* | 164 | 3.0 |
| DWJ3230 | 30 ton | 3 ½ | .5625 pitch 1.125 lead ACME 2C |
32:1 | 28.5 | 60 | .064W* | .030W* @ 200 RPM | 18.6 | .384W* | 164 | 3.0 |
| WJ1135 | 35 ton | 3 ¾ | .666 pitch ACME 2C |
11:1 | 16 | 70 | .093W* | .057W* @ 200 RPM | 17.4 | .328W* | 240 | 3.4 |
| WJ3235 | 35 ton | 3 ¾ | .666 pitch ACME 2C |
32:1 | 48 | 70 | .055W* | .026W* @ 200 RPM | 12.9 | .328W* | 240 | 3.4 |
| (R)WJT1150 | 50 ton | 4 ½ | .666 pitch ACME 2C |
11:1 | 16 | 100 | .095W* | .063W* @ 150 RPM | 15.8 | .378W* | 387 | 6.1 |
| (R)WJT3250 | 50 ton | 4 ½ | .666 pitch ACME 2C |
32:1 | 48 | 100 | .050W* | .027W* @ 150 RPM | 12.4 | .378W* | 387 | 6.1 |
| WJ1175 | 75 ton | 5 | .666 pitch ACME 2C |
11:1 | 16 | 155 | .107W* | .067W* @ 150 RPM | 14.8 | .418W* | 610 | 6.5 |
| WJ3275 | 75 ton | 5 | .666 pitch ACME 2C |
32:1 | 48 | 155 | .056W* | .028W* @ 150 RPM | 11.7 | .418W* | 610 | 6.5 |
| WJ12100 | 100 ton | 6 | .750 pitch ACME 2C |
12:1 | 16 | 205 | .112W* | .072W* @ 90 RPM | 13.9 | .495W* | 1010 | 10.0 |
| WJ36100 | 100 ton | 6 | .750 pitch ACME 2C |
36:1 | 48 | 205 | .059W* | .031W* @ 90 RPM | 10.8 | .495W* | 1010 | 10.0 |
| WJ12150 | 150 ton | 7 | 1.00 pitch ACME 2C |
12:1 | 12 | 300 | .134W* | .084W* @ 90 RPM | 15.7 | .595W* | 1350 | 12.2 |
| WJ36150 | 150 ton | 7 | 1.00 pitch ACME 2C |
36:1 | 36 | 300 | .070W* | .037W* @ 90 RPM | 12.1 | .595W* | 1350 | 12.2 |
| WJ50250 | 250 ton | 9 | 1.00 pitch ACME 2C |
50:1 | 50 | 500 | .036W* @ 60 RPM | 8.8 | .711W* | 3415 | 21.0 |
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.