Two stage telescopic jack units (TJ and TJR series) consist of upper and lower pistons, a cylinder, and a head bearing and packing gland for each piston. The lower piston is fitted with an additional packing gland at the lower end which rides against the internally honed cylinder.
Three stage telescopic jack units (TJ3 series) consist of upper, intermediate, and lower pistons, a cylinder, and a head bearing and packing gland for each piston. The intermediate and lower pistons are fitted with additional packing glands at their lower ends which ride against the internally honed cylinder and lower piston.
The telescopic jacks have a synchronous design where all pistons raise and lower at the same speed and at the same time.
Telescopic jacks are provided in one section only (no multi-section) and are designed for “guided” applications only where the frame to which the jack unit is attached is rigidly supported and guided. In some applications a guided stabilizer may be required on the upper head to meet code requirements.
Two stage telescopic jacks are available from 1.6” to 4.5” upper piston diameter, in a wide range of wall thicknesses. They are designed for in-ground and holeless or partial in-ground applications, cantilever or dual systems, and can be used on residential systems.
Three stage telescopic jacks are available from 1.6” to 2.5” upper piston diameter. They are designed for only holeless applications, cantilever or dual systems, and can be used on residential systems.
The jacks are designed to operate at temperatures up to 150°F (65°C). Recommended operating temperature is 65° to 95°F (18° to 35°C).
All EECO jack units are designed and manufactured in accordance with ASME A17.1. Cylinders and pistons are manufactured from ASTM A 53, grade B, steel pipe, ERW or seamless as required; or from equivalent steel tubing.
All steel parts are fabricated and machined from high strength carbon steel. All welding is in accordance with the requirements of Part 8 of ASME A17.1.
Standard TJ Series Jack Units
The jack heads are designed for ease of disassembly when repacking. An oil collection groove is provided and arrangement is included to connect an oil drain line to catch and reclaim oil that collects in the groove (it is necessary for the piston to carry a film of oil through the packing in order to provide smooth and quiet operation). The external packing gland arrangement consists of a “pressure balanced” “U” type seal, a phenolic bearing and a wiper ring. Recommended hydraulic fluid is 32 grade turbine oil, 150 SSU. A biodegradable oil is acceptable if it meets the same specifications.
The upper end of the piston is fitted with a drilled and tapped plate, to receive a standard bolt for attachment to the platen plate (special mounting arrangements can be provided). The bottom of the piston is closed with a steel plate and is fitted with a stop ring to prevent the piston from leaving the cylinder. The piston is ground and polished to a surface finish of 15 to 20 micro-inches. Allowable variation in diameter after polishing is ± .015”.
Jack units manufactured for in-ground or partial in-ground installations are furnished with a safety bulkhead and seamless steel pipe cap at the bottom of the cylinder. Standard pit supports are welded to the cylinder for mounting to pit channels when required (various designs can be provided to suit any requirement). Holeless units include a flat steel mounting plate, all in accordance with ASME A17.1. Bleeder plugs are included to purge air from the jack unit. A threaded or grooved oil line connection is provided. All cylinders are thoroughly cleaned, inspected, and tested for oil leaks; and then painted with a heavy coat of an anti-corrosive material..
EECO can provide optional types of cylinder protection beyond the standard coating material, including: