The Pfaff-Silberblau S20 and S24 are hand-operated worm gear drives, designed as bolt-on gearbox accessories for the ZWW-L and ZWW wall-mounted rack & pinion jack ranges. The worm gear provides a reduction ratio between the operator's crank and the jack pinion shaft, substantially reducing the required hand effort at the cost of more crank rotations, and both models are self-locking when the crank is released — additional load holding alongside the jack's own load brake. S20 fits the ZWW-L light-duty range (25 mm shaft); S24 fits the ZWW heavy-duty range (36 mm shaft).
Key Features
- Reduction ratio 20:1 (S20) or 24:1 (S24): Substantially reduces required hand effort for heavy loads.
- Self-locking when released: Worm gear is self-locking, providing additional load holding alongside the jack's own load brake.
- Bolt-on installation: Mounts to ZWW-L or ZWW jack body via standard bolt pattern, connects to pinion shaft via coupling.
- Hand-operated via standard Pfaff cranks: See Pfaff Cranks product for compatible cranks.
- Motor drive integration: Available for combined manual/motor operation.
Technical Specifications
| Model |
Article No. |
Reduction Ratio |
Drive Torque (daNm) |
Input Shaft Dia. (mm) |
Application |
| S20 |
32626004 |
20:1 |
12 |
25 |
ZWW-L 300 to 1200 light-duty wall jacks |
| S24 |
32626020 |
24:1 |
36 |
36 |
ZWW 1500 to 10000 heavy-duty wall jacks |
Worm gear drives are bolt-on gearbox accessories for the ZWW-L and ZWW ranges, not standalone lifting equipment. Both are self-locking when the crank is released. Refer to the dimensional drawing for installation envelope.
CE & UKCA Marked | DIN 7355 Compliant | German Engineered
Pfaff-Silberblau is part of the Columbus McKinnon group, one of the world's largest manufacturers of motion technology and lifting equipment. This product is CE marked (EU Machinery Directive 2006/42/EC) and UKCA marked (UK Supply of Machinery (Safety) Regulations 2008), manufactured to DIN 7355 (Steel jacks acc. to DIN), and is supplied with a Declaration of Conformity. LOLER 1998 thorough examinations are required every 12 months by a competent person after initial certification.
More About This Product
The Pfaff-Silberblau S20 and S24 are hand-operated worm gear drives, designed as bolt-on gearbox accessories for the ZWW-L and ZWW wall-mounted rack & pinion jack ranges. The worm gear provides a reduction ratio between the operator's crank and the jack pinion shaft, substantially reducing the required hand effort at the cost of more crank rotations. Both models are self-locking when the crank is released, providing additional load holding alongside the jack's own load brake. S20 fits the ZWW-L light-duty range (25 mm shaft); S24 fits the ZWW heavy-duty range (36 mm shaft).
Suitable Applications
Used wherever a ZWW-L or ZWW jack needs to be operated with reduced hand effort. Applications: heavy industrial maintenance, sluice gate auxiliary drives, building services, automated systems requiring manual emergency drive.
Matched pumps, cylinders and accessories are needed to complete the circuit.
How to Use the Pfaff-Silberblau Worm Gear Drive S20 / S24
- Select correct gearbox: S20 for ZWW-L (25 mm shaft); S24 for ZWW (36 mm shaft).
- Mount the gearbox: Bolt to the jack body per the Operating Manual.
- Connect to pinion shaft: Engage the shaft coupling between gearbox output and jack pinion.
- Fit operating crank: Use a standard Pfaff crank matched to the gearbox input shaft.
- Operate the jack: Steady crank rotation. Hand effort significantly reduced vs direct operation.
- Self-locking action: When crank released, worm gear self-locks holding the load.
Warning:
The S20 and S24 are gearbox accessories, not standalone lifting equipment. System WLL is determined by the jack itself, not the gearbox. Do not exceed the jack's WLL.
Safety Information
- Verify the worm gear drive matches your jack (S20 for ZWW-L; S24 for ZWW).
- Jack determines system WLL, do not exceed jack rating.
- Inspect worm gear, shaft coupling, and crank engagement before each use.
- Lubricate annually per the Operating Manual.
- Remove from service if self-locking action fails.
Inspection and Maintenance
Periodic lubrication (annually under normal use; 6 months under heavy duty). Use the lubricant grade in the Operating Manual (typically gear oil ISO VG 220). Inspect at each LOLER examination. WOLFF Onsite provides spare parts and overhaul.
Optional Accessories
- Pfaff Cranks: Standard cranks for operating the worm gear input.
- ZWW-L jacks (for S20): See Pfaff ZWW-L Wall-Mounted Rack & Pinion Jack.
- ZWW jacks (for S24): See Pfaff ZWW Wall-Mounted Rack & Pinion Jack.
- Motor drive integration: Available on request for combined manual/motor operation.
Downloads
Frequently Asked Questions
Q: S20 or S24?
S20 (20:1, 12 daNm, 25 mm shaft) for ZWW-L 300-1200. S24 (24:1, 36 daNm, 36 mm shaft) for ZWW 1500-10000. Not interchangeable, different shaft sizes.
Q: How much effort reduction?
Approximately proportional to ratio. S20 (20:1) reduces effort 20x at the cost of 20x more rotations. S24 (24:1) reduces 24x at 24x more rotations.
Q: Is the worm gear self-locking?
Yes. When crank released, worm self-locks preventing reverse rotation. Combined with jack load brake provides highly secure load hold.
Q: Can I retrofit to an existing jack?
Yes, the worm gear is a bolt-on accessory. Field retrofit can be done by a competent person with standard tools.
Q: Does it affect the jack's WLL?
No, WLL is determined by the jack. The worm gear reduces hand effort but doesn't increase lifting capacity.
Q: Can the S20 or S24 worm gear drive be motor-driven?
Yes, motor drive integration is available on request. The motor connects to the worm gear's input shaft via a coupling, with the manual crank retained as emergency drive. Contact us for motor drive specification including three-phase electric drives and AUMA rotary drives.
Q: How often does the worm gear need lubrication?
Annually under normal industrial use, or every 6 months under heavy-duty use. The lubricant grade is specified in the Operating Manual (typically gear oil ISO VG 220). Lubrication is part of the standard LOLER examination procedure.
