The suction valve ball is within the chamber and opens with each draw of the plunger. When the plunger moves forward, it pushes the oil through a discharge check valve into the cylinder. When the plunger pulls back, it draws oil out of the reservoir through a suction check valve into the pump chamber. Oil is used since it is self lubricating and stable. Hydraulic jacks are often used to lift elevators in low and medium rise buildings.Ī hydraulic jack uses a liquid, which is incompressible, that is forced into a cylinder by a pump plunger. Use of jacks not designed for a specific vehicle requires more than the usual care in selecting ground conditions, the jacking point on a vehicle, and to ensure stability when the jack is extended. Hydraulic jacks are typically used for shop work, rather than as an emergency jack to be carried with the vehicle. In 1851, inventor Richard Dudgeon was granted a patent for a "portable hydraulic press" – the hydraulic jack, a jack which proved to be vastly superior to the screw jacks in use at the time. In 1838 William Joseph Curtis filed a British patent for a hydraulic jack. The working principle of a hydraulic jack The first attestation in the Oxford English Dictionary of jack in the sense 'a machine, usually portable, for lifting heavy weights by force acting from below' is from 1679, referring to 'an Engine used for the removing and commodious placing of great Timber.' Jackscrew Scissor jack From here, the word was 'applied to things which in some way take the place of a lad or man, or save human labour'. The personal name Jack, which came into English usage around the thirteenth century as a nickname form of John, came in the sixteenth century to be used as a colloquial word for 'a man (of low status)' (much as in the modern usage 'jack of all trades, master of none'). Industrial jacks can be rated for many tons of load. Jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons). The most common form is a car jack, floor jack or garage jack, which lifts vehicles so that maintenance can be performed. A mechanical jack employs a screw thread for lifting heavy equipment. A jack is a mechanical lifting device used to apply great forces or lift heavy loads.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |