कलणारे ट्रक (यंत्र)

ह्या लेखाचा/विभागाचा इंग्रजी किंवा अमराठी भाषेतून मराठी भाषेत भाषांतर करावयाचे बाकी आहे. अनुवाद करण्यास आपलाही सहयोग हवा आहे. ऑनलाईन शब्दकोश आणि इतर सहाय्या करिता भाषांतर प्रकल्पास भेट द्या.

साचा:Global कलणारा ट्रक (टिपर/डंपर) हा माती, वाळू ,केरकचरा वाहून नेण्याच्या कामी येतो. या प्रकारच्या ट्रकमध्ये चालकाच्या मागे असलेला सामान भरण्याचा डबा हा तरलशास्त्राच्या धर्तीवर चालणाऱ्या दट्ट्यास जोडला असून त्याच्या मागील भागास बिजागऱ्या लावलेल्या असतात. समोरील भाग उचलला जातो व त्यातील सामग्री ही जमिनीवर पडते. जेथे बांधकाम सुरू असते त्या ठिकाणी जे कलणारे ट्रक वापरले जातात त्यास इंग्लंड व ऑस्ट्रेलियात डंपर ट्रक म्हणतात, तर रस्त्यावर चालणाऱ्या या प्रकारच्या वाहनास टिपर म्हणतात. मूलतः हे दोन्ही त्याच्या कार्याचे दृष्टीने एकच आहेत.

कलणारा ट्रकचा जनक रॉबर्ट .टी. मॉवहिने हा होय. सेंट जॉन ब्रुन्सविक या ठिकाणी, सन १९२० मध्ये साध्या ट्रकच्या मागे एक डबा जोडला. या ट्रकमध्ये उचलण्याचे उपकरण हे एका केबलला जोडलेले चक्र व रहाटयंत्र (Winch) असून, ही सर्व व्यवस्था चालकाच्या मागे एका खांबावर बसविण्यात आली होती. हा तारदोर (Cable) डब्याच्या समोरील भागास खाली जोडला होता आणि ट्रकच्या मागील भागास एका केंद्रकीले (Pivot)ला जोडला होता. चालक हा एका तरफेच्या साहाय्याने तो डबा उचलू वा ठेवू शकत असे.^[१][२] आजकाल बहुतक सर्व ट्रक हे तरलशास्त्रावरील उपकरणे वापरून चालतात. यामध्ये बांधकामांच्या सामानपुरवठ्याच्या साखळीशी संबंधित विशिष्ट कामे करण्यासाठी, अनेकविध प्रकारांची सरमिसळ करण्यात आलेली असते.

प्रमाणबद्ध कलणारा ट्रक म्हणजे यात ट्रकच्या चासीला (Chassis) डबा लावण्यात आलेला असतो. तो तरलशास्त्रीय धारकाने (Ram) ट्रकच्या समोरील भागास जोडलेला असून त्याचा पाठीमागील भाग बिजागऱ्यांनी एका धातूच्या चौकटीस जोडला असतो. पाठीमागचे दार असल्यास त्याच्या वरील भागास ते बिजागऱ्यांनी जोडून झुलत्या अवस्थेत ठेवता येते. त्याला वर उचलण्याची ट्रकांच्या काही प्रकारात वेगळी व्यवस्था असते.

अमेरिकेत अशा प्रकारच्या ट्रकला समोर एक आस (Axle) असतो आणि मागे एक वा अनेक आस असतात, त्या आंसास जोडचाके बसविलेली असतात. सामान्य वापराच्या ट्रकला सहा चाकी म्हणतात. दहा चाकीस मागे दोन आस असतात. सर्वात अजस्र ट्रकला मागील बाजूस सात आस असतात. सर्वात पुढील आस वळवण्याच्या कामासाठी असतो तर सर्वात मागील आसास इंजिनाची ताकद पुरवली जाते. सर्वात पुढील व सर्वात मागील आसादरम्यान असलेले सर्व आस हे ट्रकच्या चौकटीवरील वजनाचे वितरण समान व योग्य तऱ्हेने व्हावे यासाठी मदत करतात. यात वेगवेगळ्या देशाचे वेगवेगळे प्रकार आहेत.^{[notes १]}या ट्रकांचे संयुक्त वजन ३२ टन राहु शकते.^[३]

युरोपीय देशांमध्ये कलणाऱ्या ट्रकांना पुढे एक आस असतो तर मागील बाजूस अनेक आस असतात. मागच्या प्रत्येक ॲक्सलला दोन्हीकडे दोन-दोन चाके असतात. सहाचाकी, दहाचाकी आणि सोळाचाकी ट्रकांना मागे एक, दोन आणि तीन ॲक्सल असतात.^{[notes २]} युरोपियन देशांमध्ये या ट्रकांचे संयुक्त वजन हे ३२ टनांपर्यंत मर्यादित केलेले असते.^[४]

तोकडा चाकतळवा असलेले ट्रक हे अधिक क्षमतेच्या ट्रकपेक्षा जास्त हाताळण्यायोग्य असतात.

राशिपातक (Dumper) हे अवजड मालाची वाहतूक करणारे एक यंत्र आहे. बांधकाम जगतात 'आर्टिक्यूलेटेड डंप ट्रक' ज्यास "युक" असेही म्हणतात, यात केबिन व डंप बॉक्स यामध्ये एक बिजागरी असते. पण तो सेमी ट्रेलर ट्रकपेक्षा वेगळा असतो. त्यात केबिन ही वेगळी करता येण्याजोगी नसून ती एकसंध असते. सुकाणू (Steering) हे तरलशास्त्रीय धारकाद्वारे संपूर्ण केबिनला तोलते. अवघड मार्गात याचा जास्त वापर करण्यात येतो. पण यास देखभालीचा खर्च बराच असतो.^[५]

A transfer dump is a standard dump truck which pulls a separate trailer which can also be loaded with aggregate (gravel, sand, asphalt, klinker, snow, wood chips, triple mix, etc.)

The second aggregate container, (B box)^[६] on the trailer, is powered by either an electric, pneumatic motor or hydraulic line,. It rolls on small wheels, riding on rails from the trailer's frame, into the empty main dump (A) box. This maximizes payload capacity without sacrificing the maneuverability of the standard dump truck. Transfer dumps are typically seen in the western United States because of the peculiar weight restrictions on western highways.

Another configuration seen is called a Triple Transfer Train, which consists of a B and C box. These are common on Nevada and Utah Highways but not in California. Depending on the axle arrangement, a Triple Transfer can haul up to 129,000 grams with a special permit in certain US states. The Triple Transfer usually costs a contactor about $105 an hour while a A/B config usually runs about $85 per hour (2007 stats).

Transfer dump trucks typically haul between 26 and 27 tons of aggregate per load, each truck is capable of 3-5 loads per day, generally speaking.

A truck and pup is very similar to a transfer dump. It consists of a standard dump truck pulling a dump trailer. The pup trailer, unlike the transfer, has its own hydraulic ram and is capable of self-unloading.

A Superdump is a straight dump truck equipped with a trailing axle, a liftable, load-bearing axle rated as high as 13,000 pounds. Trailing 11 to १३ फूट (४.० मी) behind the rear tandem, the trailing axle stretches the outer "bridge" measurement—the distance between the first and last axles—to the maximum overall length allowed. This increases the gross weight allowed under the federal bridge formula, which sets standards for truck size and weight. Depending on the vehicle length and axle configuration, Superdumps can be rated as high as 80,000 pounds GVW and carry 26 tons of payload or more. When the truck is empty or ready to offload, the trailing axle toggles up off the road surface on two hydraulic arms to clear the rear of the vehicle. Truck owners call their trailing axle-equipped trucks Superdumps because they far exceed the payload, productivity, and return on investment of a conventional dump truck. The Superdump and trailing axle concept was developed by Strong Industries of Houston, Texas.

A semi end dump is a tractor-trailer combination wherein the trailer itself contains the hydraulic hoist. A typical semi end dump has a 3-axle tractor pulling a 2-axle semi-trailer. The key advantage of a semi end dump is rapid unloading. A key disadvantage is that they are very unstable when raised in the dumping position limiting their use in many applications where the dumping location is uneven or off level.

A semi bottom dump (or "belly dump") is a 3-axle tractor pulling a 2-axle trailer with a clam shell type dump gate in the belly of the trailer. The key advantage of a semi bottom dump is its ability to lay material in a wind row (a linear heap). In addition, a semi bottom dump is maneuverable in reverse, unlike the double and triple trailer configurations described below. These trailers may be found either of the windrow type shown in the photo, or may be of the 'cross spread' type with the gates opening front to rear instead of left and right. The cross spread gates will actually spread gravel fairly evenly the width of the trailer. by comparison, the windrow gates leave a pile in the middle. The cross spreads jam and do not work well with larger materials. Likewise they are not suitable for use where spreading is not desired such as when hot asphalt paving material is being dumped in front of a paving machine.

Double and triple bottom dumps consist of a 2-axle tractor pulling one single-axle semi-trailer and an additional full trailer (or two full trailers in the case of triples). These dump trucks allow the driver to lay material in windrows without leaving the cab or stopping the truck. The main disadvantage is the difficulty in backing double and triple units.

The specific type of dump truck used in any specific country is likely to be closely keyed to the weight and axle limitations of that jurisdiction. Rock, dirt and other types of materials commonly hauled in trucks of this type are quite heavy, and almost any style of truck can be easily overloaded. Because of this, this type of truck is frequently configured to take advantage of local weight limitations to maximize the cargo. For example, within the United States, the maximum weight limit of 40 tons throughout the country, except for specific bridges with lower limits. Individual states, in some instances, are allowed to authorize trucks up to 52.5 tons. Most states that do so require that the trucks be very long, to spread the weight over more distance. It is in this context that double and triple bottoms are found within the US.

A side dump truck consists of a 3-axle tractor pulling a 2-axle semi-trailer. It has hydraulic rams which tilt the dump body onto its side, spilling the material to either the left or right side of the trailer. The key advantages of the side dump are that it allows rapid unloading and can carry more weight in western United States. In addition, it is almost immune to upset (tipping over) while dumping unlike the semi end dumps which are very prone to tipping over. It is, however, highly likely that a side dump trailer will tip over if dumping is stopped prematurely. Also, when dumping lose materials or cobble sized stone, the side dump can become stuck if the pile becomes wide enough to cover too much of the trailer's wheels. Trailers that dump at the appropriate angle (50° for example) avoid the problem of the dumped load fouling the path of the trailer wheels by dumping their loads further to the side of the truck, in some cases leaving sufficient clearance to walk between the dumped load and the trailer.

Off-road dump trucks ^[७] more closely resemble heavy construction equipment or engineering vehicles than they do highway dump trucks. They are used strictly off-road for mining and heavy dirt hauling jobs.

The term ‘Dump’ Truck is not generally used by the mining industry, or by the manufacturers that build these machines. The more appropriate US term for this strictly off road vehicle is, ‘Haul’ truck and the equivalent European term is 'Dumper'. The classification bottom and side for example, describes how the loaded material is discharged once loaded. In the case of the Haul truck illustrated, a Liebherr T 282B the load is discharged to the rear, designating this particular vehicle as an end dump.

Bottom dump normally describes a trailer that discharges its load by opening two clam shell doors under the load space, in some examples several trailers (road train) are pulled by one truck mainly these are on road machines. The only remaining example of what is described as a unitized bottom dump coal hauler is manufactured by Kress Corporation. This large capacity truck is used for the transportation of coal from a loading device (shovel) directly to a power station or bulk storage area.

The current largest off road haul trucks are the Liebherr T282B and the Caterpillar 797F, which both have payloads of 400 short tons. Even though these trucks are similar in capacity the Caterpillar is referred to as a mechanical truck since it uses a C175-20 20 cylinder diesel and big transmissions to power the rear wheels. The Liebherr is referred to as a Diesel-Electric Truck since it uses a diesel engine linked to an alternator that generates electricity which is converted to AC used to power two giant electric motors found on the rear wheel assemblies, similar to a locomotive (it is a series plug-in hybrid). Besides Liebherr and Caterpillar, Hitachi, Terex, Komatsu and others also fabricate such off road haul trucks in different capacities.

हिवाळ्यात बर्फवृष्टीमुळे सेवा देणाऱ्या वाहनांची रचना ही डंप ट्रकांसारखीच असते. बर्फावर पसरविण्यासाठीची रसायने याद्वारे वाहून नेली जातात.

Dump trucks are normally built for some amount of off-road or construction site driving; as the driver is protected by the chassis and height of the driver's seat, bumpers are either placed high or omitted for added ground clearance. The disadvantage is that in a collision with a standard car, the entire motor section or luggage compartment goes under the truck. Thus, passengers in the car could be more severely injured than would be common in a collision with another car. Several countries have made rules that new trucks should have bumpers approximately ४० सेंमी (२० इंच) above ground in order to protect other drivers better. There are also rules about how long the load or construction of the truck can go beyond the rear bumper to prevent cars that rear-end the truck from going under it.^[८]

यात लक्षात घेण्याजोगा सुरक्षेचा मुद्दा असा की रिता करण्यापूर्वी ट्रकला योग्य समपातळीवर राखले गेले पाहिजे. ट्रक रिकामा करतांना एकाचवेळी अचानकपणे होणारा वजनातील बदल व त्याचा मागचा भाग उचलला गेल्याने आवश्यक असा तोल न सांभाळता न आल्याने कधीकधी ट्रक घसरतात किंवा पलटतात.

त्यांच्या आकारामुळे व पायी कामगार त्यांच्या चालकाला (ट्रकच्या उंचीमुळे) दिसू न शकल्याने, विषेशतः मागे घेतांना ते अशा कामगारांना धोकादायक ठरू शकतात.^[९]मागचे दृष्य दाखविणारे आरसे (Rear View Mirrors) व वाहन मागे घेतेवेळी वाजणारा भोंगा (Alarm) याद्वारे हे धोके कमी होतात. चालकासमवेत एक कामगार असल्यासही हे धोके बरेच कमी होतात.^[१०]

अशा प्रकारचे ट्रक चालविण्याच्या प्रशिक्षणाची व्यवस्था एकतर कंपनीतर्फे किंवा प्रशिक्षण संस्थेतर्फे करण्यात येते.

• VRML Simulation of an Excavator, Tower Crane, and Dumptruck Archived 2007-12-14 at the Wayback Machine. from the National Institute of Standards and Technology
• A YouTube video of a dump truck raising and lowering it load tray