… of course you have to use a lift. This is an obvious truth, but in this article we will not deal with the well-known small lifts, thanks to which you can, e.g. replace the wheel on the road, but we will present the most popular types and versions of professional workshop equipment, as well as the drive used in them.
The most popular type of workshop hoists are the so-called Two-column. The vehicle is lifted on them thanks to two pairs of arms, placed on trolleys moving vertically in the column guides. At the ends of the arms there are so-called paws, i.e. brackets, which slide under the car floor plate (in most constructions, the arms can be extended using special extension cords mounted between them and the paws). Thanks to their location, the car can be raised and lowered with complete relief of both its wheels and suspension. An unquestionable advantage of two-column lifts is the ability to operate vehicles with very low suspension and low ground clearance.
Symmetrical and asymmetrical
Two-column lifts are offered in the two versions mentioned above. In the symmetrical version, all four lift arms have the same length. In turn, the asymmetrical version has one long and one short arm on each column. Thanks to this asymmetrical solution, these lifts ensure a more even distribution of the lifted masses than is the case with the symmetrical variety. This is particularly important because in the case of cars, their heaviest components, such as the engine or transmission, are not symmetrical, and are most often located at the front or rear axle of the vehicle.
Electromechanical or electrohydraulic?
Two-column lifts also differ in the type of drive used in them. Older versions have electromechanical, which is implemented by a screw mechanism. How it’s working? The rotational movement of the screw is converted into the longitudinal (in this case vertical) feed of the nut attached to the trolley. The disadvantage of lifts with electromechanical drive is, above all, their loud operation, as well as the need for frequent maintenance work. Electrohydraulic lifters are much better in this respect. In their case, the so-called the phenomenon of multiplication of the lifting force, carried out by a hydraulic transmission consisting of a pump and piston cylinders placed vertically in columns. The most common are jacks equipped with two cylinders driven by a common hydraulic pump. To ensure even lifting of the trolleys on both columns, it is necessary to place a synchronization beam between them. Depending on the version of the lift, it can be placed on top of the columns or at the bottom of them.
Advantages and disadvantages
Which lift version is better? In the case of a synchronization beam located at the bottom of the columns, their advantage is their lower height, i.e. the possibility of using them in small workshop rooms or servicing larger vehicles, such as delivery vans, e.g. campers. In turn, the inconvenience is the need to drive the vehicle over the beam. The most important advantage of jacks with upper synchronization beam is their stability. What is going on? For these versions, no strong foundations are necessary, as is the case with bottom beam constructions. In addition, the upper location of the synchronization beam allows you to operate cars with a very low clearance. Just like the version with a lower beam, also the upper beam is not without flaws. Due to its location, the most serious is the difficult operation of taller vehicles, as well as the need to have a high workshop room – on average in the range of 4-5 meters.