Information AboutJackhammer |
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| construction | |
| cutting tools | |
| pneumatic tools | |
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. Pneumatic hose can be seen leading to the Compressor on the back of the truck. The operator is using his body weight to increase the effectiveness of the device.]] A pneumatic drill or '''jackhammer''' is a Portable percussive Drill , operated by Compressed Air and used to drill Rock , break up Pavement , etc. It works in the manner of a Hammer and Chisel , by jabbing with its bit, not by rotating it. (A drill, driven by compressed air, which rotates its cutting bit is called an Air-drill or, more familiarly, a windy-drill or Rotary Hammer .) The word ''jackhammer'' is used in North American English and in Australia , and ''pneumatic drill'' is used colloquially elsewhere in the English Speaking World , although ''(road) breaker'' is used in the trade. The portable Pneumatic jackhammer is impractical for use on walls and steep slopes as it relies on the Inertia of the Mass of its body to impel the bit into the work and manipulating that mass when it is not supported by the work is highly difficult. Besides, Gravity is required to bring the mass back into contact with the work after each blow. Though it is unhealthy practice, the operator may lean on the tool to assist but he is not really capable of overcoming the forces involved when he is not assisted by gravity. A technique developed by experienced laborers is the use of two man teams to overcome this obstacle of gravity. One laborer operates the hammer and the second assists by holding the hammer either on his shoulders or cradled in his arms. Both use their combined weight to push the bit into the workface. This method is commonly referred to as horizontal jackhammering. Another method is overhead jackhammering, requiring strength conditioning and endurance to hold a smaller jackhammer, called a rivet buster, over ones head for eight to ten hours a day. Its pneumatic hose connections are designed so that any hose end will connect with any hose end without the workman having to keep track of . HYDRAULIC OPERATION A Hydraulic jackhammer (on a much larger scale than the portable ones) may be fitted to mechanical Excavator s or Backhoe s and is widely used for roadwork, quarrying and general demolition or constructional groundwork. In Mining , it is possible to use this against a vertical wall as the machine can be jacked off the opposite wall of the Gallery or some comparable device. For reasons of safety, pneumatic tools are likely to be used underground on a Coal mine. Hydraulic breakers will usually use a hydraulic motor to drive a sealed pneumatic hammer system, as a hydraulic hammer would not only develop a poor striking speed but transfer unacceptable shock loads to the pump system. ELECTRO-MECHANICAL OPERATION While the term "jackhammer" is occasionally used to mean "pneumatic drill", the Electromechanical tool that performs the same function is normally the one called a "jackhammer" in Britain . This tool is useful where the work is light and not accessible from a Compressor . The Makita breaker pictured uses standard 25mm (1") points and chisels identical to the ones used in medium sized Pneumatic tools. It draws 1300W of power and weighs about 19 kg (about 42 pounds) with a point in it. This type and size of machine is commonly hired by amateurs for renovation type jobs. HEALTH The sound of the repeated hammer blows combined with the explosive exhaust of the air, makes pneumatic jackhammers dangerously noisy, emitting 100 Decibel s at two meters. Sound-blocking Earmuffs must be worn by the operator to prevent a form of Hearing damage of which Tinnitus is the main Symptom . As a result, most pneumatic jackhammers now have a Silencer around the barrel of the tool: it is the black part in the image below. Prolonged exposure to the very pronounced Vibration set up by the tool can lead to Blood -circulation failures in the Finger s, a condition known as White Finger . Using atheltic-tape to tape the fingers is not effective but seems to make some difference. Furthermore, pneumatic drill usage can predispose one to developing Carpal Tunnel Syndrome . TYPES OF JACKHAMMERS 90 lb 60 lb (most common) Rivet Buster (remenants from when rivets were used, effective tool) 35 lb 22 lb Chipping gun (small jackhammer with variable speed trigger) Small chipping gun BITS Spade - provides flat finish for concrete or edging in asphalt or dirt Flat tip - allows direction control or finer edge finish Point - general breaking Stake driver - drives form stakes Scrabbler - finshes surface smooth or for cleaning prior to bonding IMAGES |
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