This is a 3 stage helical gearbox with a planetary gear attached in final stage. Helical Gear box could be 35:1 ratio to 120: 1 Ration possible for minimum 25Kw to 5 Kw power rating while final stage is 3.3 Ratio, totally 115:1 to 375:1ratio gearbox is possible. The planetary gear RIM gear should be attached in to the drum for final torque delivery. Total Gearbox Center Distance is 550mm

1. RAJANI HOIST & CRANES PRESENTS
Crane Gearbox
Helical/Planetary train
Book
6

2. This is a promotional package, Strictly Not for Commercial purpose
M U L T I S T A G E H E L I C A L C U M P L A N E T A R Y D E S I G N , C A L C U L A T I O N S & A P P L I C A T I O N
Crane duty gearbox Design proposal
DOUBLE GEAR
Transmission Elements
Powered by
 Double Gear transmission elements
#7 Muthumari chetty street. Mannady,Broadway,Chennai, INDIA
Mob +91-9791222047
E-mail: ceo.doublegear@gmail.com, www.doublegear.co.in
Over 20 years, DOUBLE GEAR has earned a nationally recognized reputation for
expertise in power transmission engineering and automation, cranes, hoist and crane duty
modular gearbox design would helps engineers and manufacturers to construct robust
infrastructures without any complications and completely tested & trusted.

3. i
WELCOME
Good Morning, I am Nagarajan from INDIA doing material handling
equipment manufacturing, supplying and exporting, I always used to dream
something innovative way to develop concepts and ideas in my field of
engineering
So for I have designed various components for the cranes, For example
gearboxes, Electrical wire rope Hoists, electrical safety circuits and accessories.
Among these, my Drum rope guide design, Cross pulling prevention
Mechanisms, hypocycloid limit switches are very famously accepted in my
colleagues organizations
This time I have developed new design for gearboxes, It is very innovative idea
for carne applications particularly for driving Rope drum application. Normally
Drums are driven by Center shaft/ bull gear with pinion, which consume more
power and make the gearbox stressful. The reason is the driven element is
getting load from outer circumference, while driving element is laboring from
center of the load. This might make the torque depletion
By arranging The final stage Planetary method, The generated torque is evenly
distributed to the all parts of the rotating part with Ring gear attached inside the
drum and more safe from single shaft/pinion failure
Comparing to conventional method by attaching Bull Gear with pinion, it is
very compact and efficient , I would like to share my concept with you for
further developments and improvements. I like to hear your valuable opinions,
please share if you like this
Thanks
Nagarajan.B +91 9791222047 ( CEO)
rajanihoistandcranes@gmail.com
Thursday, May 9, 2019

4. ii
SECTION 1 Basic idea
Picture showing how the Gear box has been assembled
This is a 3 stage helical gearbox with a planetary gear attached in final stage.
Helical Gear box could be 35:1 ratio to 120: 1 Ration possible for minimum
25Kw to 5 Kw power rating while final stage is 3.3 Ratio, totally 115:1 to 375:1
ratio gearbox is possible. The planetary gear RIM gear should be attached in to
the drum for final torque delivery. Total Gearbox Center Distance is 550mm

5. iii
SECTION 2 Data Sheet of the helical part
Picture shows the Data Sheets of the Helical Gears manufacturing details
This data sheets shows the design, calculations and Gear manufacturing
details. The total gearbox design follows DIN 3990 method B drafting.
Gearbox has been split in to 140+190+220=550mm. Blank OD, Gear
cutting Details and Quality inspection details are given. Please see below
topic for further details

6. iv
SECTION 3 Gear Design Details
A close look of the Gear Finishing
The strength calculation (tooth fracture, pitting, wear and temperature
safeties) The strength calculations are carried out according to norms
(DIN 3990, ISO 6336, etc.). it is maintained 15 Degree helix left for Gears
and The same Right angle for pinion to balanced operation
Furthermore, it is necessary to have some knowledge about gear
technology, as you have to interpret the results. In general, one can say
that, according to DIN 3990, part 11 (Industrial gear boxes), a safety
factor for the root of 1.4 and a safety factor for Hertzian stress of 1 is
sufficient. But we maintain 1.5 Service factors

7. v
• Application Factor (service factor)
The application factor considers uncertainties in load and impacts. It is
always larger than or equal as 1. A hint for the factor can be found in the
following table and more comprehensive information is available in DIN
3990, DIN 3991 or ISO 6336.
Working
condition of
the Driving
Force
Working condition of the driven
machine
Uniform Moderate Medium Heavy
Uniform 1 1.25 1.5 1.75
Moderate
Impact 1.1 1.35 1.6 1.85
Medium
Impact 1.25 1.5 1.75 2
Heavy Impact 1.5 1.75 2 2.25
• Tooth thickness deviations (backlash)
The geometry of the gears is calculated for backlash free state. To prevent
the gears from jamming, the tooth thickness is manufactured slightly
smaller (than the theoretical value). This decrease of the tooth thickness is
called tooth thickness deviation. The upper tooth thickness deviation
represents the maximal allowable thickness and the lower the minimal.
Tolerance according DIN 3967
Centre Distance
Optimizing the centre distance regarding balanced sliding At a
predetermined addendum modification factor for gear, the centre distance
is calculated with this option, to compensate for balanced sliding of the
gear pair. The calculation is carried out with automatic tip radius reduction
according DIN 3960 Tolerance according to ISO (z.B. js6)

8. vi
SECTION 4 Gear Quality Control method
Picture shows how Gears and pinions are meshing
All gears and pinions are having Addendum modification factor for
balances sliding for noiseless operation.the proposal represents the
addendum modification required for balanced specific sliding between
pinion and wheel
While Gears and Pinions are manufacturing, Span measurement over the
no of teeth is strictly maintained according to the Addendum
modifications and Center Distance. If the gears are designed for profile
grounding,

9. vii
A close look of the Specific Sliding
Specific sliding is shown as condition of sliding where
engaged flanks slides to transfer the rotation except
area of pitch point
Sliding velocity is the relative velocity in a transverse plane of a
common contact point between mating gear teeth. As shown in
Figure it is the vectorial difference between the two rolling
velocities that are tangential to the tooth profiles and
perpendicular to the line of action. See references AGMA ( 2005)
and ISO ( 2007) for gear nomenclature and definitions of terms.

10. viii
SECTION 5 How the Drum and Gearbox is connected
Picture Shown Rope drum connected in to the Gearbox
The planetary Rim gear is fastened in to the Drum inside. While the
Carrier is fixed with Gearbox Housing, The planet Gears will rotate ring
gears subsequently drum will rotate on the speed of Sun gear to Rim Gear
ratio
Drum Rotation always Same direction to Motor Shaft rotation
Due to 3 stage and Planetary gears

11. ix
Picture Shown Open View
Advantages:
• Drum Circumference Evenly get Torque
• Easy to maintenance For Serving
• Consuming Less Power
• More Compact for larger size drums
Disadvantages (I feel some improvements requires)
1. More moving parts
2. Unique Ring gears required for Different OD Drums
3. Manufacturing Cost Slightly increased

12. x
The actual performances of this Design could be justified after
manufactured and tested, Engineers, amateurs and friends Please give
your suggestions and opinions for improvements
I have future plans for implementing energy saving alpha starting
gearboxes, Rapide Speed Gearboxes and compressors for Cross travel
also. Definitely I would share my experience. Stay touched
Please Note: This a prototype proposal. Still not verified & tested, If you
like it, Please request me, I will send you manufacturing Drawings and
specifications. Try to do improve yourself and share your experience &
knowledge
Thanks For Reading
Nagarajan
CEO, Rajani Hoist and cranes
BANGALORE , INDIA
Saturday, May 11, 2019