FAQ
* Input Torque: T=(F*p / 2*π*i*η) + To
* Input Power: P=F*V / 60*η, P=T*n/9550, V=n*p / 1000*i
* Worm Gear Ratio: I=(n / 1000*V)*p
* Travel Speed: V=n*p / i
* Hand Turnning Force: HF=T/R, HF=F*p / i*R*1000
To = Idling torque (Nm)
S = Stroke (mm)
L = Travels (mm) per turn of jack input shaft
HF = Hand turning force (kg)
R = Radius of hand wheels (m)
f1: factor for driven machine
| Load Characteristic | Example | Factor for driven machine (f1) |
| Uniform load, small inertia | Shifting device for switches, valves and conveyors | 1.0 < f1 ≤ 1.3 |
| Moderate shock load, medium inertia | Moving devices and elevators | 1.3 < f1 ≤ 1.5 |
| Heavy shock load, large inertia | Heavy trolleys and railway lifts | 1.5 < f1 ≤ 3.0 |
Ws: Total Equivalent Load Ws (N)
| Number Of Jacks In Arrangement | 1 | 2 | 3 | 4 | 5~8 |
| Arrangement Factor | 1 | 0.95 | 0.9 | 0.85 | 0.8 |
* Verification The Stability Of Screw: Pcr=fm*d4/L2 ensure Pcr>W*SF (SF=4)
Pcr = Critical load (N)
Verify the screw stability when the axial compression load exists. If the load is greater than the critical load, increase the sizes before calculation.
A = 2.5*104, B = 1*105, C = 2*105
Ball screw: the unit of %ED for a single screw jack is 10 minutes duty circle max. 50%ED; 30 minutes duty circle max. 30%ED; 60 minutes duty circle max. 20%ED.
Two screw jacks lift system, transmission efficiency 95%
Three screw jacks lift system, transmission efficiency 90%
Four screw jacks lift system, transmission efficiency 85%
Six screw jacks lift system, transmission efficiency 80%
Eight screw jacks lift system, transmission efficiency 80%
Notes: don’t ignore the bevel gearbox efficiency 98%.
Oil lubricant is better than grease. Less resistance at the start and high efficiency. Possible in high-speed operation Etc.
Normal operating conditions are -20ºC to 80ºC. Please consult sales@liftingmotion.com for applications that require temperatures outside this range.
- Machining precision level eight
- Radial play is 0.2mm
- Trapezoidal screw end play is 0.15mm
- Lifting screw outer diameter and sleeve diameter free tolerance is 0.2mm
- Worm shaft and gear play is ± 3 degrees for ratio N, and ± 5 degrees for ratio L
Stop nut are offered as options for screw jacks, and are not to be used as operating limits. Engaging the stop may prevent damage to your structure but will most likely damage the jack. To control jack or actuator travel, include limit switches in the system design. Including stops may increase the closed height of the jack and the length of the protection tube.
Closed height dimensions may increase when boots are added. Standard material is Neoprene coated nylon. Special boot material is available. Horizontal screw applications may require boot guides.
Our worm gear jacks are lubricated with 0# or 1# lithium grease prior to shipment. You can find more specific information from our Operation & Maintenance Manuals.
The travel Speeds of the screw actuators mainly depend on the input RPM, load, internal ratio and lead of the screw. Maximum allowable travel speeds for machine screw jacks are typically slower than ball screw jacks. Worm gear jacks have slower travel speeds than bevel gear jacks.
For our model NDLB high-speed screw actuator, it uses both ball screw and bevel gear, which make the speed quite fast. Pay attention that the input horsepower to these screw jacks should not exceed the hp rating shown in the specifications tables. Maximum RPM should not exceed 1500.
The worm gear actuators efficiency is low, so the duty cycle is also low at the rated load. If you reduce the load or increase model NO, the duty cycle can be increased. Talk to our engineering sales for more information.
Maximum input RPM may be slower than 1500 RPM depending on the dynamic load and other factors specific to the application. You can contact sales@liftingmotion.com and talk with an application engineer.
The load must be positioned axially. The standard screw jack is not designed for dynamic side loads. Static side loads are limited. Where side thrusts are present, the loads should be guided and let the guides take the side thrust especially when long travel length is involved. Even a small side load can exert great force on the housings and bearings and increase the operating torque. Contact sales@liftingmotion.com for technical assistance.
The duty cycle is the relationship between operation time and rest time. The allowable duty cycle for screw jack actuator is based upon several application variables such as load, speed, and temperature. Contact sales@liftingmotion.com and talk with an application engineer about your requirements.
The life of a machine screw actuator varies considerably due to extent of lubrication, or improper maintenance, eccentric loading, abrasive, chemical, overloading, excessive heat, , etc.
We warrant that its screw jack sold will be free of defects in material and workmanship in a period of 13month from the original date of receipt. During this period, Nuodun will repair or replace defective parts free of charge.
This warranty covers only normal use of the products. We will not repair or replace any parts that become unusable and show clear evidence of improper maintenance, eccentric loading, overloading, excessive heat, chemical or abrasive wear, tampering or abuse. Equipment and accessories not manufactured by Nuodun are warranted only to the extent the manufacturer warrants them, and only if the claimed defect arose during normal use, application and service. Equipment that has been altered or modified by anyone without our authorization is not warranted. Except as stated herein, Nuodun makes no other warranties, express or implied including warranties of merchantability and fitness for a particular purpose.