13-09-2014, 02:33 PM
DESIGN AND FABRICATION FABRICATION OF MOTORIZED MOTORIZED
SCREW JACK FOR A FOUR WHEELER PROJECT REPORT
DESIGN AND FABRICATION.pdf (Size: 753.98 KB / Downloads: 33)
INTRODUCTION
Power screws are used to convert rotary motion into
translatory motion.
• A screw jack is an example of a power screw in which a small
force applied applied in a horizontal horizontal plane is used to raise or lower a
large load.
• The principle on which it works is similar to that of an inclined
plane.
FORMS OF THREADS
• Two popular types of threads used for power screws are
square and I.S.O metric trapezoidal.
• There is a special type of thread called acme thread. In acme
thread, the thread angle is 29°.
• Another type of thread used is called buttress thread. It
combines the advantages of square and trapezoidal threads.
MOTORIZED SCREW JACK
• The motorized screw jack has been developed to cater to the
needs of small and medium automobile automobile garages garages.
• In most of the garages the vehicles are lifted by using screw
jack. This needs high man power and skilled labor
WORKING PRINCIPLE
• The screw jack moves the screw upward, so that the vehicle
lifts from ground.
• The vehicle is lifted by using the lifting platform at the top of
the screw jack.
• The lead‐acid battery is used to drive the d.c motor.
• The motor draws power supp yl from the battery.
• The d.c motor shaft is connected to the spur gear.
• The lifting and uplifting is done by changing the battery
supply to the motor.
SCREW JACK
• A screw jack is a portable device consisting of a screw
mech i an sm used to raise or lower the l d oa .
• The principle on which the screw jack works is similar to that
of an inclined plane.
• Typically this is used to change a tire although other
maintenance is sometimes performed.
• There are mainly two types of jacks
(i) Hydraulic
(ii) Mhil ec anical
• A hydraulic jack consists of a cylinder and piston mechanism
MECHANICAL JACKS
Scissor Jacks
• A scissor jack is a device constructed with a cross‐hatch
mechanism, much like a scissor, to lift up a vehicle for repair
or storage.
• It typically typically works in just a vertical vertical manner.
• The jack opens and folds closed, applying pressure to the
bottom supports along the crossed pattern to move the lift.
• When closed, they have a diamond shape
BATTERIES
• In isolated systems away from the grid, batteries are used
for storage storage of excess solar energy which can be converted converted
into electrical energy.
• To be economically attractive the storage of solar electricity
requires a battery with a particular combination of properties:
1. Low cost
2. Long life
3. High reliability
4. High overall efficiency
5. Low discharge
6. Minimum maintenance
SPUR GEAR
The spur g , ears which are designed to transmit motion and
power between parallel shafts, are the most economical
gears in the power transmission industry.
Design considerations for a gear drive
• In the design of a gear drive, the following following data is usually usually
given:
1. The power to be transmitted,
2. The speed of the driving gear,
3. The speed of the driven gear or the velocity ratio, and
4. The centre distance.
CONCLUSION
• Screw Jacks are the ideal product to push, pull, lift, lower and
position loads of any g thin from a couple of kilograms to
hundreds of tonnes.
• The need has long existed for an improved portable jack for
aut ti omo ve vehi l c es.
• The main requirement of a motorized screw jack is stability. It
should be easily controllable by a switch so that j g ackin can
be done from a position of safety. It should also be easily
movable either to a position underneath the axle of the
vehicle vehicle or some other reinforced reinforced support support surface surface designed designed to
be engaged by a jack.
• Thus, the product has been developed considering all the
above requirements.