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SERVICES – Installation – Hydraulic Elevators

We install hydraulic elevators by a variety of manufacturers.

Commercial hydraulic elevators fall into two basic categories; conventional (or in-ground) and holeless. We only install the holeless variety. Years ago my father, my brother and I made a policy decision based upon the premise that the placing of a hydraulic cylinder in the ground where it could not be observed or maintained, and the accompanying exposure of ground water contamination, made in‑ground hydraulics an inferior choice.

All hydraulic elevators are raised by a column of oil that is forced into a cylinder by a motor driven pump through a control valve. While there have been many improvements over the years such as electronically controlled valves and variable frequency motor control, the system is effectively the same as it was forty years ago.

The actual lifting is done by a piston mounted within a casing or cylinder (jack assembly). Car speed, acceleration, deceleration and relief pressure are regulated by a control valve mounted between the pump and the cylinder or by a variable voltage variable frequency motor driving a pump at different speeds. When the motor turns the pump, the pump creates pressure which drives the piston and elevator up. To come down,  a valve is opened which allows the oil previously pumped into the casing to flow back into the reservoir, allowing the car and piston to come down .

In-ground elevators are so called because the cylinder goes down into the ground as far as the elevator travels up. This type of installation requires the drilling of a hole below the elevator. Typical installations today utilize a steel liner to prevent the hole from caving in, a PVC liner to protect the steel cylinder from electrolytic action and, normally, to contain a device or viscous substance that is intended to prevent the cylinder from chemical reactions, i.e. oxidation. As previously stated, RMR does not install this type of elevator. Due to the inability to observe and maintain the jack assembly after it is placed into the ground, we have determined that there is no need to expose our customer or our firm to the liability associated with an underground hydraulic oil leak.

Holeless elevators are so called because they do not use a conventional under cab piston/casing arrangement. Holeless elevators come in many different styles. The two predominant types are direct-acting and roped. Holeless hydraulic elevator equipment is typically more expensive than in-ground equipment; however, the additional expense is offset by the high cost of drilling a jack hole. The other benefit to hole add hyphen between hole and less less equipment is that there is no possibility of an environmental contamination.

Direct acting holeless elevators employ a piston that is connected directly to the steel that supports the elevator cab. Typically this requires either a cantilevered platform support or a second jack assembly mounted on the opposite side of the cab.. Also included in this category are telescopic jacks that have multiple pistons within a single jack assembly. Direct acting hydraulic elevators are only practical for a limited amount of travel.

Roped hydraulic elevators are more complicated as they employ an indirect attachment to the car. Roped hydraulic elevators utilize the same steel cables that support high rise elevators but in a 1:2 arrangement. (See Illustration) In this manner the cab will move two inches for every inch the piston travels. Roped hydraulic elevators are equally well suited to new installations, retrofits into an existing building, applications where drilling a hole for the jack assembly is impractical or in an application where travel is more than is practical for a direct acting hydraulic elevator.